Eur Arch Otorhinolaryngol (2015) 272:1457–1463 DOI 10.1007/s00405-015-3535-7
LARYNGOLOGY
Clinical and biochemical characteristics of patients with Fusobacterium necrophorum-positive acute tonsillitis Ann Marlene Gram Kjærulff • Marianne Kragh Thomsen Therese Ovesen • Tejs Ehlers Klug
•
Received: 13 November 2014 / Accepted: 29 January 2015 / Published online: 10 February 2015 Ó Springer-Verlag Berlin Heidelberg 2015
Abstract Fusobacterium necrophorum (FN) is the predominant pathogen in peritonsillar abscesses, which is a relatively frequent complication of acute tonsillitis. The study aimed to explore if FN is a significant pathogen in acute tonsillitis, examine the prevalence of FN in acute tonsillitis patients, and describe the clinical and biochemical characteristics of FN-positive patients. A 6-month prospective study was conducted in a Danish general practice with eight physicians. One hundred acute tonsillitis patients and 100 healthy controls aged 15–40 years were included in the study. The prevalence of FN was (non-significantly) higher among acute tonsillitis patients (16 %) compared to healthy individuals (9 %) (P = 0.199). This trend was border significant for patients aged 15–29 years (24 vs 9 %) (P = 0.050). Significantly, more FN-positive patients were men (75 %) compared to patients growing other bacteria (17 %) or mixed oral flora (27 %) (P \ 0.001). Centor scores, individual clinical symptoms, and infection markers were similar between patient growing FN and mixed oral flora. FN is possibly a significant and prevalent pathogen in acute tonsillitis
A. M. G. Kjærulff (&) T. Ovesen T. E. Klug Department of Otorhinolaryngology, Head and Neck Surgery, Aarhus University Hospital, Noerrebrogade 44, 8000 Aarhus C, Denmark e-mail: [email protected] T. Ovesen e-mail: [email protected] T. E. Klug e-mail: [email protected] M. K. Thomsen Department of Clinical Microbiology, Aarhus University Hospital, Brendstrupga˚rdsvej 100, 8200 Aarhus N, Denmark e-mail: [email protected]
among teenagers and young adults. Patients with FNpositive acute tonsillitis do not seem to be more clinically or biochemically affected than patients without growth of bacterial pathogens. Keywords Acute tonsillitis Fusobacterium necrophorum Clinical characteristics Biochemical parameters C-reactive protein, procalcitonin
Introduction Acute tonsillitis is a common reason for consultation in general practice. The most frequent bacterial pathogen in acute tonsillitis is group A streptococcus (GAS), which is recovered from 11 to 26 % of cases [1–3]. At present, antibiotic treatment is only recommended in cases of acute tonsillitis with a positive test for GAS [culture or streptococcal rapid antigen detection test (RADT)] [4]. The clinical characteristics of patients with GAS-positive acute tonsillitis are well described. Centor’s criteria (oral temperature C38.3 °C, tonsillar exudate, absence of cough, and enlarged cervical lymph nodes) are commonly used to estimate the probability of GAS infection in patients with acute tonsillitis [5, 6] and thus guide clinicians if a RADT should be performed (generally recommended in patients who meet 2–4 of Centor’s criteria). The reliability of the RADT is high (sensitivity 83–94 % and specificity 97–100 %) and the test result is available within a few minutes [6, 7]. However, the RADT only provides information concerning GAS and the widespread diagnostic reliance on this test by (Danish) general practitioners may leave other bacterial pathogens undetected and untreated, which may be one of the reasons for the very high incidence rate of peritonsillar abscess in Denmark [8].
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Fusobacterium necrophorum (FN) is known to be the cause of Lemierre’s syndrome [9]. Recent studies from our institution document that FN is also the most prevalent pathogen in peritonsillar abscess development [8, 10]. Both Lemierre’s syndrome and peritonsillar abscess are complications of acute tonsillitis and it is therefore likely that FN can also be of pathogenic importance in uncomplicated acute tonsillitis. A few previous studies suggest that FN may be an important pathogen in acute tonsillitis among teenagers and young adults (in 5–15 % of cases) [2, 3, 11]. However, no studies have characterized FN-positive patients with acute tonsillitis. Furthermore, the prevalence of FN among patients with acute tonsillitis is unknown. The aims of the current study were to 1. investigate if FN is a significant pathogen in uncomplicated acute tonsillitis. 2. explore the prevalence of FN in acute tonsillitis patients in a Danish general practice. 3. characterize (clinically and biochemically) FN-positive patients with acute tonsillitis.
Methods Study population This prospective study was performed at Skoedstrup general practice (with eight physicians) in the period between August 27, 2012 and March 5, 2013. All observations and tests were performed by the corresponding author at the time of consultation. Informed consent was obtained from all individual participants included in the study. A screening log was recorded including all patients with sore throat during the period of recruitment. Only patients with acute tonsillitis who met the inclusion criteria were asked to participate in the study. The inclusion criteria were: (1) age between 15 and 40 years, (2) subjective and objective signs of acute tonsillitis fulfilling one or more of the Centor´s criteria (temperature C38.3 °C, tonsillar exudate, enlarged cervical lymph nodes, and absence of cough), (3) no antibiotic treatment within the past month, (4) no other infections within the past month, (5) no recurrent acute tonsillitis without a 3-month intermediate healthy period, (6) no suspicion of peritonsillar abscess, and (7) no previous tonsillectomy. The diagnosis of acute tonsillitis was based on typical symptoms (sore throat and pain on swallowing) and clinical findings of tonsillar exudate or hyperemia. To make bacteriological comparisons, 100 equally aged, healthy individuals (controls), who sought consultation for non-infectious reasons, were also included in the study.
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None of the controls had subjective or objective signs of infection at the time of consultation, were previously tonsillectomized, or were treated with antibiotics or had an infection within the past month. The study was approved by the Danish Ethics Committee (ID: 1-10-72-321-12) and the Danish Data Protection Agency (ID: 2007-58-0010). Data were registered at ClinicalTrials.gov (ID: NCT01657968). Microbiological specimens Two swabs were simultaneously rubbed at the tonsillar surfaces and the posterior pharyngeal mucosa of all patients. The cotton swab was used for the RADT (Alere Test Pack ? Plus with on-board controls), and the charcoal impregnated cotton swab was transported to the Department of Clinical Microbiology in Stuart’s transport medium (SSI Diagnostica, Hilleroed, Denmark). Similarly, a tonsillar surface and posterior pharyngeal mucosa swab for bacterial culture was obtained from the healthy controls. The median time between tonsillar swabbing and cultivation was 4 h. Five percent blood agar, chocolate agar, and specific Fusobacterium agar plates (all from SSI Diagnostica, Hilleroed, Denmark) were used for microbiological culture. The swab was semi-quantitatively applied to the various plates using a dilution streak technique. The first quadrant of the plate was streaked using the swab and each successive quadrant was streaked using a new bacteriologic loop to dilute the number of bacteria in each quadrant. We assumed that the semi-quantitatively growth of bacteria was correlated with the amount of bacteria present on the swab. The blood agar plates and the chocolate agar plates were incubated in a CO2-enriched atmosphere, whereas the Fusobacterium agar plates were incubated anaerobically. All agar plates were incubated at 35 °C for a maximum of 72 h. In previous studies of tonsillar microbiology, FN was recovered from 58 % of non-abscessed, acutely inflamed tonsils when the plates were incubated for 72 h. Hence, this time period seems sufficient to detect FN from tonsillar specimens. The plates were inspected for growth of GAS, group C/G hemolytic streptococci, FN, Arcanobacterium hemolyticum, and Corynebacterium diphtheriae. Identification was performed by standard methods including MALDI-TOF MS (Bruker Daltonic, Germany). FN was detected based on colony morphology with beta-hemolysis and the smell of butyric acid and fluorescence of a chartreuse color in ultraviolet light. Light to moderate growth of viridans streptococci, Neisseria species, Lactobacillus species, coagulase-negative staphylococci, Prevotella species, and Fusobacterium non-necrophorum alone or in mixture were reported as ‘‘mixed oral flora’’.
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Biochemical parameters Total recruitment: 195 patients (69 men)
The PCT measurement was based on the Elecsys BRHAMS PCT test (Cobas e601 module on a Cobas 6000). Analysis of CRP, WBC, and ANC levels were carried out daily at the Department of Clinical Biochemistry.
Not aged between 15 and 40 years: 71 patients
Statistical methods The Student’s t test and the analysis of variance (ANOVA) were used for comparisons of normally distributed data. The normality of the data was assessed using histograms and quantile–quantile (QQ) plots. The Kruskal–Wallis test was used for the non-normally distributed data. For statistical analyses of binary data, the Fisher exact test and the Chi square test (v2 test) were used. Statistical significance was assumed at P \ 0.05.
Centor score < 1: 8 patients Antibiotic treatment within the past month: 6 patients Recurrent acute tonsillit within the past 3 month: 2 patients Suspicion of a peritonsillar abscess: 1 patient
Results During the 6-month study period, a total of 195 patients with sore throat consulted the general practice. The reasons for non-inclusion of 95 sore throat patients are illustrated in Fig. 1. One hundred patients with acute tonsillitis (31 males) (patient group) and 100 healthy individuals (32 males) (control group) were included in the study. The mean ages of the patient group and the control group were 28 years and 29 years, respectively (range 15–40 years). The median duration of symptoms before consultation was three days (range 1–21 days). FN was recovered from 16 % of patients and 9 % of controls. This difference was statistically insignificant (P = 0.199; Fisher’s exact test). GAS was more frequently isolated from patients (26 %) than healthy controls (3 %) (P \ 0.001). No significant difference in the detection rates of group C/G streptococci between patients (10 %) and controls (6 %) was found (P = 0.435). There was a strong trend towards a higher FN isolation rate among patients aged 15–29 years (24 %) compared to patients aged 30–40 years (10 %) (P = 0.054; Fisher’s exact test) (Table 1). FN was detected with equal prevalence in healthy individuals aged 15–29 years (9 %) and 30–40 years (8 %) (P = 0.734). The prevalence of FN among acute tonsillitis patients aged 15–29 years (24 %) was (almost significantly) higher than among healthy controls aged 15–29 years (9 %) (P = 0.050). However, no difference in semi-quantitative growth of FN was found between patients and controls aged 15–29 years (P = 0.745). No significant difference was found between FN recovery rates between patients aged 30–40 years
Rejected to participate: 3 patients Missing evaluation: 4 patients
Total study inclusion: 100 patients (31 men)
Fig. 1 Flow chart illustrating the causes for exclusion of patients
Table 1 Recovery rates of Fusobacterium necrophorum in 100 patients with acute tonsillitis and 100 healthy individuals stratified by age Age (years)
Acute tonsillitis patients (%)
Healthy controls (%)
Pa
15–29
24
9
0.050
30–39
10
8
0.745
All
16
9
0.199
a
Fisher’s exact test
(10 %) and equally aged healthy controls (8 %) (P = 1.000). Patients with growth of FN was significantly more frequently males (75 %) compared to patients with beta-
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hemolytic streptococci (17 %) (P \ 0.001; Fisher’s exact test) or mixed oral flora (27 %) (P \ 0.001) (Table 2). No association between smoking behavior and recovery of FN compared to other bacteria was found among acute tonsillitis patients (P = 1.000; Fisher’s exact test) or healthy controls (P = 0.592). No significant differences in the prevalence of anamnestic fever (P = 1.000; Fisher’s exact test), tonsillar exudate (P = 0.754), enlarged cervical lymph nodes (P = 1.000), or absence of cough (P = 0.756) were found between FN-positive patients and patients with mixed oral flora. Only one patient (with mixed oral flora) had an oral temperature above 38.3 °C (Table 2). FN-positive patients (excluding patients co-infected with FN and beta-hemolytic streptococci) had only marginally, and statistically insignificantly, higher mean values of PCT (P = 0.180; Kruskal–Wallis test), CRP (P = 0.178; t test), WBC (P = 0.184; t test), and ANC (P = 0.830; t test) compared to patients with mixed oral flora. Patients with growth of both FN and beta-hemolytic streptococci had markedly higher mean values of PCT, CRP, WBC, ANC, Centor score, and semi-quantitative bacterial growth compared to patients with mixed oral flora. However, this trend of higher clinical and biochemical parameters was based on relatively few patients and did not reach statistical significance (PCT (P = 0.844; Kruskal–Wallis test), CRP (P = 0.206; t test), WBC (P = 0.154; t test), ANC (P = 0.927; t test), Centor score (P = 0.917; Fisher’s exact test), and semi-quantitative bacterial growth (P = 0.581; Fisher’s exact test). No significant differences in the mean values of PCT (P = 0.817; Kruskal–Wallis test), CRP (P = 0.646; t test), WBC (P = 0.816; t test), and ANC (P = 0.251; t test) were found between patients growing FN and group C/G streptococci (Table 2). No statistically significant difference in Centor scores was found between patients with FN and mixed oral flora (P = 0.190; Fisher’s exact test). All FN-positive patients with Centor score 3 had moderate or heavy growth of FN (3?/4?). No correlation between the mean values of PCT, CRP, WBC, or ANC and Centor score or heaviness of FN growth was found (Table 3).
Discussion Previous studies from our institution have documented that FN is the predominant pathogen in peritonsillar abscesses, which is the most frequent complication of acute tonsillitis [8, 10]. Other studies indicate that FN may also play a role in acute tonsillitis [3, 11, 12]. While previous studies have analyzed the findings in
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throat swabs sent from general practitioners for bacterial culture, the current study is the first to prospectively collect throat specimens for culture from well-defined patients and to characterize FN-positive patients with acute tonsillitis. We aimed to compare the clinical and biochemical characteristics of FN-positive acute tonsillitis patients with healthy controls and sore throat patients with other bacterial findings to further substantiate a role of FN in uncomplicated acute tonsillitis and to explore possible indicators of FN-infection. Batty et al. detected FN in seven of 49 (14 %) patients with tonsillitis (including quinsy), but did not compare this finding with culture results from healthy controls [2]. Aliyu et al. [11], using PCR, detected FN DNA in ten of 100 swabs from sore throat patients (two FN-positive patients also had growth of beta-hemolytic streptococci), but in none of 100 controls (mean age 40 years). Jensen et al. [12] detected the presence of FN DNA on 29 (48 %) swabs from patients with non-streptococcal acute tonsillitis, which was significantly more than in the control swabs (21 %). Lastly, Eaton et al. [13] detected FN in 28 of 502 (5.6 %) cultures from tonsillar surface swabs from patients with tonsillitis, but did not compare these findings with culture results from healthy controls. Using conventional culture methods and specific FN agar plates, we detected FN in 16 % of tonsillar surface swabs from acute tonsillitis patients aged 15–40 years and in 9 % from equally aged healthy controls. This trend for higher FN isolation rate among patients with acute infection was statistically insignificant (P = 0.199). In designing the study and the number of patients needed to show the proposed difference in FN isolation rates, we underestimated the frequency of FN colonization in healthy individuals. Hence, the study may be underpowered to reveal a possible difference in FN isolations rates. Another possible inexpediency in our study design is the fact that we included patients aged 15–40 years. A very recent study of patients with peritonsillar abscess showed that FN is much more prevalent in patients aged 15–24 years than patients with other ages [14]. Similar findings have been done in patients with Lemierre’s syndrome [9]. The current study underscores this trend of FN affecting teenagers and young adult most frequently. FN was isolated (almost) significantly more frequently among patients aged 15–29 years (24 %) compared to equally aged healthy controls (9 %). On the contrary, patients aged 30–40 years and equally aged controls had similar FN recovery rates (10 vs 8 %). Our findings in healthy subjects confirm that FN can be part of the normal oropharyngeal flora and stress that the detection of FN in tonsillar surface swabs should be interpreted with caution. Another limitation of the study is that viral etiology was conceived in patients without recovery of the defined
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Table 2 Clinical and biochemical characteristics of 100 patients with acute tonsillitis stratified by bacterial findings Variables
Fusobacterium necrophorum
Fusobacterium necrophorum ? betahemolytic streptococcus
Group A streptococcus
Group C/G streptococcus
Mixed oral floraa
No of patients
12
4
26
10
48
No of men
9 (75 %)
3 (75 %)
3 (12 %)
3 (30 %)
13 (27 %)
Pb
Pc
Patient data
Age (years)
26 (15–36)
No of smokers
2 (17 %)
29 (24–35) 0 (0 %)
33 (18–40) 5 (19 %)
25 (16–38) 0 (0%)
27 (15–39) 7 (15 %)
0.001d
0.005e
f
0.593g
d
1.000e
h
0.001 0.565
4 (1–21)
3 (2–4)
3 (1–14)
3 (1–6)
5 (1–21)
0.043
0.569h
Per-oral temperature (°C)
36.8 (36.5–37.0)
37.3 (36.6–37.9)
37.1 (36.9–37.3)
37.0 (36.6–37.3)
36.7 (36.5–36.8)
0.004f
0.472g
Positive streptococcal antigen testi
0 (0 %)
3 (75 %)
23 (88 %)
0 (0 %)
2 (4 %)
\0.001d
1.000e
0.03 (0.02–0.40)
0.18 (0.02–0.38)
0.04 (0.02–0.09)
0.04 (0.02–0.75)
0.03 (0.02–0.51)
0.189h
0.180h
12 (6–28)
43 (7–284)
24 (15–38)
6 (2–17)
6 (4–8)
\0.001f
0.178g
f
Symptom duration (days) Clinical tests
Infection markers Procalcitonin (lg/l) C-reactive protein (mg/l) 9
White blood cell count (10 /l)
8.9 (7.2–10.7)
13.4 (6.6–20.3)
10.9 (9.6–12.1)
9.2 (7.1–11.4)
7.7 (6.8–8.5)
\0.001
0.184g
Absolute neutrophil count (109/ l)
5.0 (3.3–6.7)
8.5 (0.1–17.0)
8.4 (7.2–9.5)
6.6 (4.1–9.0)
4.8 (4.0–5.7)
\0.001f
0.830g
6 (50 %)
0 (0 %)
2 (8 %)
2 (20 %)
22 (46 %)
0.004d
1.000e
19 (40 %)
d
0.185e
d
Total Centor score Score 1 Score 2
2 (17 %)
2 (50 %)
10 (38 %)
6 (60 %)
0.333
Score 3
4 (33 %)
2 (50 %)
14 (54 %)
2 (20 %)
7 (15 %)
0.007
0.206e
Score 4
0 (0 %)
0 (0 %)
0 (0 %)
0 (0 %)
0 (0 %)
–
–
0 (0 %)
0 (0 %)
0 (0 %)
0 (0 %)
1 (2 %)
0.859d
1.000e
d
0.754e
d
0.756e
d
1.000e
Distribution of Centor’s criteria Oral temperature C38.3 °C Tonsillar exudate Absence of cough Enlarged cervical lymph nodes
6 (50 %) 7 (58 %) 9 (75 %)
4 (100 %) 4 (100 %) 2 (50 %)
21 (81 %) 22 (85 %) 21 (81 %)
5 (50 %) 5 (50 %) 10 (100 %)
21 (44 %) 25 (52 %) 34 (71 %)
0.012 0.028
0.225
Means (CI 95 %) are given for age, oral temperature, C-reactive protein, white blood cell count, and absolute neutrophil count. Medians (range) are given for symptom duration and procalcitonin a Mixed oral flora refers to light to moderate growth of viridans streptococci, Neisseria species, Lactobacillus species, coagulase-negative staphylococci, Prevotella species, and Fusobacterium non-necrophorum alone or in mixture b
All pathogens
c
Fusobacterium necrophorum vs mixed oral flora
d
Chi square test
e
Fisher’s exact test
f
Analyse of variance (ANOVA)
g
Student’s t test
h i
Kruskal–Wallis test Microbiological culture results were used as standard of reference
bacterial tonsillar pathogens, but no viral studies were performed to confirm that belief. We found no differences in Centor score and the individual symptoms and findings between patients growing FN, group C/G streptococci, and mixed oral flora. Hence, the Centor score does not seem to be useful to estimate the likelihood of FN-positive acute tonsillitis.
We found no differences in the mean values of PCT, CRP, WBC, and ANC between patients growing FN and mixed oral flora. Hence, infection markers were not useful in the detection of FN-positive acute tonsillitis. Furthermore, the infection markers were only modestly affected by the clinical infection in both patients with growth of FN, group C/G streptococci, and mixed oral flora, which may
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Table 3 Associations between Centor score, semi-quantitative growth, and infection markers in patients with Fusobacterium necrophorumpositive acute tonsillitis Semi-quantitative growth
Infection markers
?1
?2
?3
?4
Procalcitonin (lg/l)
C-reactive protein (mg/l)
White blood cell count (9109/l)
Absolute neutrophil count (9109/l)
Centor score 2
–
1 (50 %)
0 (0 %)
1 (50 %)
0.02 (0.02–0.02)
3 (0–29)
7.0 (0.3–13.7)
3.6 (0–15.7)
Centor score 3
–
0 (0 %)
2 (50 %)
2 (50 %)
0.2 (0–0.4)
25 (0–59)
10.7 (6.9–14.4)
4.3 (0–9.7)
Centor score 4
–
–
–
–
–
–
–
–
Procalcitonin (lg/ l)
–
0.05 (0–0.45)
0.12 (0–0.42)
0.07 (0–0.13)
C-reactive protein (mg/l)
–
16 (0–154)
26 (0–53)
17 (1–33)
White blood cell count (9109/l)
–
9.1 (0–28.5)
9.2 (6.3–12.1)
8.8 (4.8–12.7)
Absolute neutrophil count (9109/l)
–
6.2 (0–26.3)
5.4 (0.7–10.2)
4.4 (1.4–7.4)
Infection markers
Means (CI 95 %) are given for C-reactive protein, white blood cell count, and absolute neutrophil count Median (range) is given for procalcitonin
reflect the relatively localized tonsillar infection. In a previous study from our institution, we found that FN-positive patients with peritonsillar abscess had significantly higher mean levels of CRP and ANC compared to peritonsillar abscess patients with other bacterial findings [8]. In two case reports of patients with FN-positive acute tonsillitis, high levels of CRP (121 mg/l) [15] and WBC (10–16 9 109/l) [15, 16] were found. However, the two patients were admitted to hospital whereas our patients were primary consultations in general practice without any patients being referred to hospital. We found no correlations between the mean levels of infection markers, the Centor score, and the (semi-) quantitative growth of FN. Furthermore, unlike two previous studies using real-time PCR, we found no difference in quantitative growth of FN between patients and controls [11, 12]. Interestingly, we found highly elevated infection markers, heavy semi-quantitative growth patterns, and high Centor scores in patients with co-finding of FN and beta-hemolytic streptococci. Previous studies have pointed to synergism between FN and other bacteria (including group C/G streptococci) [12, 17]. However, Gehrt et al. [18] noted that isolation of FN in acute tonsillitis patients was negatively correlated with the detection of GAS. It has been proposed that the interaction of FN with other microorganisms increases the permeability of the tissue which facilitates the penetration of FN and thus provides access to anaerobic growth conditions in the deeper layers of tissue [3]. We found that male acute tonsillitis patients were significantly more often FN positive compared to females.
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Hagelskjaer et al. [19] noted that FN-positive acute tonsillitis was observed more often in females than in males among teenagers under the age of 17 years, whereas males dominated in older age groups. Eaton et al. [13] isolated FN most frequently in tonsillitis patients aged 10–29 years, and observed a higher FN incidence rate among girls aged 10–19 years compared to boys at the same age. Furthermore, males were more frequently infected with FN in the age group 20–29 years. Similarly, the incidence rate of peritonsillar abscess was significantly higher in girls aged 13–14 years compared to boys at the same age, but subsequently males had higher incidence rates than females and this was statistically significant for the age groups 20–29 years and 40–49 years [14]. Amess et al. [3] found an equal male/female ratio among patients with FN-associated sore throat. A recent study from our institution found that smoking was associated with significantly increased risk of peritonsillar abscess in both males and females of all age, and that there was no difference in the microbiological flora between smokers and non-smokers [20]. In the current study, we found no association between individual bacteria and smoking habits in patients with acute tonsillitis.
Conclusion The current study stresses that FN is a part of the normal oropharyngeal flora and that culture results regarding FN
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should be interpreted with caution. We found a strong trend for higher isolation rates of FN in younger (15–29 years) patients with acute tonsillitis compared to equally aged healthy controls, and FN is likely to be a significant and prevalent pathogen among young adults with uncomplicated acute tonsillitis. This finding seems clinically very important as these teenagers and young adults are at the highest risk of abscess development with FN and timely diagnosis and antibiotic treatment may avoid suppurative complications. The Centor score, individual symptoms and clinical findings, infection markers, and semi-quantitative growth patterns do not seem to be of value in the detection of FN-positive patients with acute tonsillitis. Acknowledgments The authors are thankful to Skoedstrup general practice, 8541 Skoedstrup, Denmark for providing facilities available in the recruitment of patients. Conflict of interest of interest.
The authors declare that they have no conflict
Ethical approval All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
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1463 6. McIsaac WJ, Kellner JD, Aufricht P, Vanjaka A, Low DE (2004) Empirical validation of guidelines for the management of pharyngitis in children and adults. JAMA 291(13):1587–1595 7. Bourbeau PP (2003) Role of the microbiology laboratory in diagnosis and management of pharyngitis. J Clin Microbiol 41(8):3467–3472 8. Ehlers Klug T, Rusan M, Fuursted K, Ovesen T (2009) Fusobacterium necrophorum: most prevalent pathogen in peritonsillar abscess in Denmark. Clin Infect Dis 49(10):1467–1472 9. Hagelskjaer LH, Prag J, Malczynski J, Kristensen JH (1998) Incidence and clinical epidemiology of necrobacillosis, including Lemierre’s syndrome, in Denmark 1990–1995. Eur J Clin Microbiol Infect Dis 17(8):561–565 10. Klug TE, Henriksen J-J, Fuursted K, Ovesen T (2010) Significant pathogens in peritonsillar abscesses. Eur J Clin Microbiol Infect Dis 30(5):619–627 11. Aliyu SH, Marriott RK, Curran MD, Parmar S, Bentley N, Brown NM, Brazier JS, Ludlam H (2004) Real-time PCR investigation into the importance of Fusobacterium necrophorum as a cause of acute pharyngitis in general practice. J Med Microbiol 53(Pt 10):1029–1035 12. Jensen A, Hagelskjaer Kristensen L, Prag J (2007) Detection of Fusobacterium necrophorum subsp. funduliforme in tonsillitis in young adults by real-time PCR. Clin Microbiol Infect 13(7):695–701 13. Eaton C, Swindells J (2014) The significance and epidemiology of Fusobacterium necrophorum in sore throats. J Infect 69(2):194–196 14. Klug TE (2014) Incidence and microbiology of peritonsillar abscess: the influence of season, age, and gender. Eur J Clin Microbiol Infect Dis. doi:10.1007/s10096-014-2052-8 15. Fourage M, Bourguignat C, Fermond B, Delobel P (2013) A recurrent tonsillitis. Lancet 381(9862):266 16. Centor RM, Geiger P, Waites KB (2010) Fusobacterium necrophorum bacteremic tonsillitis: 2 cases and a review of the literature. Anaerobe 16(6):626–628 17. Brook I (2005) The association of anaerobic bacteria with infectious mononucleosis. Anaerobe 11(6):308–311 18. Gehrt B, Jensen A, Kristensen LH, Prag J (2009) Can anaerobic culture of throat swabs prevent Lemierre’s syndrome? Ugeskr Laeg 171(12):991–992 19. Hagelskjaer Kristensen L, Prag J (2008) Localised Fusobacterium necrophorum infections: a prospective laboratory-based Danish study. Eur J Clin Microbiol Infect Dis 27(8):733–739 20. Klug TE, Rusan M, Clemmensen KKB, Fuursted K, Ovesen T (2013) Smoking promotes peritonsillar abscess. Eur Arch Otorhinolaryngol. doi:10.1007/s00405-013-2474-4
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LARYNGOLOGY
Clinical and biochemical characteristics of patients with Fusobacterium necrophorum-positive acute tonsillitis Ann Marlene Gram Kjærulff • Marianne Kragh Thomsen Therese Ovesen • Tejs Ehlers Klug
•
Received: 13 November 2014 / Accepted: 29 January 2015 / Published online: 10 February 2015 Ó Springer-Verlag Berlin Heidelberg 2015
Abstract Fusobacterium necrophorum (FN) is the predominant pathogen in peritonsillar abscesses, which is a relatively frequent complication of acute tonsillitis. The study aimed to explore if FN is a significant pathogen in acute tonsillitis, examine the prevalence of FN in acute tonsillitis patients, and describe the clinical and biochemical characteristics of FN-positive patients. A 6-month prospective study was conducted in a Danish general practice with eight physicians. One hundred acute tonsillitis patients and 100 healthy controls aged 15–40 years were included in the study. The prevalence of FN was (non-significantly) higher among acute tonsillitis patients (16 %) compared to healthy individuals (9 %) (P = 0.199). This trend was border significant for patients aged 15–29 years (24 vs 9 %) (P = 0.050). Significantly, more FN-positive patients were men (75 %) compared to patients growing other bacteria (17 %) or mixed oral flora (27 %) (P \ 0.001). Centor scores, individual clinical symptoms, and infection markers were similar between patient growing FN and mixed oral flora. FN is possibly a significant and prevalent pathogen in acute tonsillitis
A. M. G. Kjærulff (&) T. Ovesen T. E. Klug Department of Otorhinolaryngology, Head and Neck Surgery, Aarhus University Hospital, Noerrebrogade 44, 8000 Aarhus C, Denmark e-mail: [email protected] T. Ovesen e-mail: [email protected] T. E. Klug e-mail: [email protected] M. K. Thomsen Department of Clinical Microbiology, Aarhus University Hospital, Brendstrupga˚rdsvej 100, 8200 Aarhus N, Denmark e-mail: [email protected]
among teenagers and young adults. Patients with FNpositive acute tonsillitis do not seem to be more clinically or biochemically affected than patients without growth of bacterial pathogens. Keywords Acute tonsillitis Fusobacterium necrophorum Clinical characteristics Biochemical parameters C-reactive protein, procalcitonin
Introduction Acute tonsillitis is a common reason for consultation in general practice. The most frequent bacterial pathogen in acute tonsillitis is group A streptococcus (GAS), which is recovered from 11 to 26 % of cases [1–3]. At present, antibiotic treatment is only recommended in cases of acute tonsillitis with a positive test for GAS [culture or streptococcal rapid antigen detection test (RADT)] [4]. The clinical characteristics of patients with GAS-positive acute tonsillitis are well described. Centor’s criteria (oral temperature C38.3 °C, tonsillar exudate, absence of cough, and enlarged cervical lymph nodes) are commonly used to estimate the probability of GAS infection in patients with acute tonsillitis [5, 6] and thus guide clinicians if a RADT should be performed (generally recommended in patients who meet 2–4 of Centor’s criteria). The reliability of the RADT is high (sensitivity 83–94 % and specificity 97–100 %) and the test result is available within a few minutes [6, 7]. However, the RADT only provides information concerning GAS and the widespread diagnostic reliance on this test by (Danish) general practitioners may leave other bacterial pathogens undetected and untreated, which may be one of the reasons for the very high incidence rate of peritonsillar abscess in Denmark [8].
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Fusobacterium necrophorum (FN) is known to be the cause of Lemierre’s syndrome [9]. Recent studies from our institution document that FN is also the most prevalent pathogen in peritonsillar abscess development [8, 10]. Both Lemierre’s syndrome and peritonsillar abscess are complications of acute tonsillitis and it is therefore likely that FN can also be of pathogenic importance in uncomplicated acute tonsillitis. A few previous studies suggest that FN may be an important pathogen in acute tonsillitis among teenagers and young adults (in 5–15 % of cases) [2, 3, 11]. However, no studies have characterized FN-positive patients with acute tonsillitis. Furthermore, the prevalence of FN among patients with acute tonsillitis is unknown. The aims of the current study were to 1. investigate if FN is a significant pathogen in uncomplicated acute tonsillitis. 2. explore the prevalence of FN in acute tonsillitis patients in a Danish general practice. 3. characterize (clinically and biochemically) FN-positive patients with acute tonsillitis.
Methods Study population This prospective study was performed at Skoedstrup general practice (with eight physicians) in the period between August 27, 2012 and March 5, 2013. All observations and tests were performed by the corresponding author at the time of consultation. Informed consent was obtained from all individual participants included in the study. A screening log was recorded including all patients with sore throat during the period of recruitment. Only patients with acute tonsillitis who met the inclusion criteria were asked to participate in the study. The inclusion criteria were: (1) age between 15 and 40 years, (2) subjective and objective signs of acute tonsillitis fulfilling one or more of the Centor´s criteria (temperature C38.3 °C, tonsillar exudate, enlarged cervical lymph nodes, and absence of cough), (3) no antibiotic treatment within the past month, (4) no other infections within the past month, (5) no recurrent acute tonsillitis without a 3-month intermediate healthy period, (6) no suspicion of peritonsillar abscess, and (7) no previous tonsillectomy. The diagnosis of acute tonsillitis was based on typical symptoms (sore throat and pain on swallowing) and clinical findings of tonsillar exudate or hyperemia. To make bacteriological comparisons, 100 equally aged, healthy individuals (controls), who sought consultation for non-infectious reasons, were also included in the study.
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None of the controls had subjective or objective signs of infection at the time of consultation, were previously tonsillectomized, or were treated with antibiotics or had an infection within the past month. The study was approved by the Danish Ethics Committee (ID: 1-10-72-321-12) and the Danish Data Protection Agency (ID: 2007-58-0010). Data were registered at ClinicalTrials.gov (ID: NCT01657968). Microbiological specimens Two swabs were simultaneously rubbed at the tonsillar surfaces and the posterior pharyngeal mucosa of all patients. The cotton swab was used for the RADT (Alere Test Pack ? Plus with on-board controls), and the charcoal impregnated cotton swab was transported to the Department of Clinical Microbiology in Stuart’s transport medium (SSI Diagnostica, Hilleroed, Denmark). Similarly, a tonsillar surface and posterior pharyngeal mucosa swab for bacterial culture was obtained from the healthy controls. The median time between tonsillar swabbing and cultivation was 4 h. Five percent blood agar, chocolate agar, and specific Fusobacterium agar plates (all from SSI Diagnostica, Hilleroed, Denmark) were used for microbiological culture. The swab was semi-quantitatively applied to the various plates using a dilution streak technique. The first quadrant of the plate was streaked using the swab and each successive quadrant was streaked using a new bacteriologic loop to dilute the number of bacteria in each quadrant. We assumed that the semi-quantitatively growth of bacteria was correlated with the amount of bacteria present on the swab. The blood agar plates and the chocolate agar plates were incubated in a CO2-enriched atmosphere, whereas the Fusobacterium agar plates were incubated anaerobically. All agar plates were incubated at 35 °C for a maximum of 72 h. In previous studies of tonsillar microbiology, FN was recovered from 58 % of non-abscessed, acutely inflamed tonsils when the plates were incubated for 72 h. Hence, this time period seems sufficient to detect FN from tonsillar specimens. The plates were inspected for growth of GAS, group C/G hemolytic streptococci, FN, Arcanobacterium hemolyticum, and Corynebacterium diphtheriae. Identification was performed by standard methods including MALDI-TOF MS (Bruker Daltonic, Germany). FN was detected based on colony morphology with beta-hemolysis and the smell of butyric acid and fluorescence of a chartreuse color in ultraviolet light. Light to moderate growth of viridans streptococci, Neisseria species, Lactobacillus species, coagulase-negative staphylococci, Prevotella species, and Fusobacterium non-necrophorum alone or in mixture were reported as ‘‘mixed oral flora’’.
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Biochemical parameters Total recruitment: 195 patients (69 men)
The PCT measurement was based on the Elecsys BRHAMS PCT test (Cobas e601 module on a Cobas 6000). Analysis of CRP, WBC, and ANC levels were carried out daily at the Department of Clinical Biochemistry.
Not aged between 15 and 40 years: 71 patients
Statistical methods The Student’s t test and the analysis of variance (ANOVA) were used for comparisons of normally distributed data. The normality of the data was assessed using histograms and quantile–quantile (QQ) plots. The Kruskal–Wallis test was used for the non-normally distributed data. For statistical analyses of binary data, the Fisher exact test and the Chi square test (v2 test) were used. Statistical significance was assumed at P \ 0.05.
Centor score < 1: 8 patients Antibiotic treatment within the past month: 6 patients Recurrent acute tonsillit within the past 3 month: 2 patients Suspicion of a peritonsillar abscess: 1 patient
Results During the 6-month study period, a total of 195 patients with sore throat consulted the general practice. The reasons for non-inclusion of 95 sore throat patients are illustrated in Fig. 1. One hundred patients with acute tonsillitis (31 males) (patient group) and 100 healthy individuals (32 males) (control group) were included in the study. The mean ages of the patient group and the control group were 28 years and 29 years, respectively (range 15–40 years). The median duration of symptoms before consultation was three days (range 1–21 days). FN was recovered from 16 % of patients and 9 % of controls. This difference was statistically insignificant (P = 0.199; Fisher’s exact test). GAS was more frequently isolated from patients (26 %) than healthy controls (3 %) (P \ 0.001). No significant difference in the detection rates of group C/G streptococci between patients (10 %) and controls (6 %) was found (P = 0.435). There was a strong trend towards a higher FN isolation rate among patients aged 15–29 years (24 %) compared to patients aged 30–40 years (10 %) (P = 0.054; Fisher’s exact test) (Table 1). FN was detected with equal prevalence in healthy individuals aged 15–29 years (9 %) and 30–40 years (8 %) (P = 0.734). The prevalence of FN among acute tonsillitis patients aged 15–29 years (24 %) was (almost significantly) higher than among healthy controls aged 15–29 years (9 %) (P = 0.050). However, no difference in semi-quantitative growth of FN was found between patients and controls aged 15–29 years (P = 0.745). No significant difference was found between FN recovery rates between patients aged 30–40 years
Rejected to participate: 3 patients Missing evaluation: 4 patients
Total study inclusion: 100 patients (31 men)
Fig. 1 Flow chart illustrating the causes for exclusion of patients
Table 1 Recovery rates of Fusobacterium necrophorum in 100 patients with acute tonsillitis and 100 healthy individuals stratified by age Age (years)
Acute tonsillitis patients (%)
Healthy controls (%)
Pa
15–29
24
9
0.050
30–39
10
8
0.745
All
16
9
0.199
a
Fisher’s exact test
(10 %) and equally aged healthy controls (8 %) (P = 1.000). Patients with growth of FN was significantly more frequently males (75 %) compared to patients with beta-
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hemolytic streptococci (17 %) (P \ 0.001; Fisher’s exact test) or mixed oral flora (27 %) (P \ 0.001) (Table 2). No association between smoking behavior and recovery of FN compared to other bacteria was found among acute tonsillitis patients (P = 1.000; Fisher’s exact test) or healthy controls (P = 0.592). No significant differences in the prevalence of anamnestic fever (P = 1.000; Fisher’s exact test), tonsillar exudate (P = 0.754), enlarged cervical lymph nodes (P = 1.000), or absence of cough (P = 0.756) were found between FN-positive patients and patients with mixed oral flora. Only one patient (with mixed oral flora) had an oral temperature above 38.3 °C (Table 2). FN-positive patients (excluding patients co-infected with FN and beta-hemolytic streptococci) had only marginally, and statistically insignificantly, higher mean values of PCT (P = 0.180; Kruskal–Wallis test), CRP (P = 0.178; t test), WBC (P = 0.184; t test), and ANC (P = 0.830; t test) compared to patients with mixed oral flora. Patients with growth of both FN and beta-hemolytic streptococci had markedly higher mean values of PCT, CRP, WBC, ANC, Centor score, and semi-quantitative bacterial growth compared to patients with mixed oral flora. However, this trend of higher clinical and biochemical parameters was based on relatively few patients and did not reach statistical significance (PCT (P = 0.844; Kruskal–Wallis test), CRP (P = 0.206; t test), WBC (P = 0.154; t test), ANC (P = 0.927; t test), Centor score (P = 0.917; Fisher’s exact test), and semi-quantitative bacterial growth (P = 0.581; Fisher’s exact test). No significant differences in the mean values of PCT (P = 0.817; Kruskal–Wallis test), CRP (P = 0.646; t test), WBC (P = 0.816; t test), and ANC (P = 0.251; t test) were found between patients growing FN and group C/G streptococci (Table 2). No statistically significant difference in Centor scores was found between patients with FN and mixed oral flora (P = 0.190; Fisher’s exact test). All FN-positive patients with Centor score 3 had moderate or heavy growth of FN (3?/4?). No correlation between the mean values of PCT, CRP, WBC, or ANC and Centor score or heaviness of FN growth was found (Table 3).
Discussion Previous studies from our institution have documented that FN is the predominant pathogen in peritonsillar abscesses, which is the most frequent complication of acute tonsillitis [8, 10]. Other studies indicate that FN may also play a role in acute tonsillitis [3, 11, 12]. While previous studies have analyzed the findings in
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throat swabs sent from general practitioners for bacterial culture, the current study is the first to prospectively collect throat specimens for culture from well-defined patients and to characterize FN-positive patients with acute tonsillitis. We aimed to compare the clinical and biochemical characteristics of FN-positive acute tonsillitis patients with healthy controls and sore throat patients with other bacterial findings to further substantiate a role of FN in uncomplicated acute tonsillitis and to explore possible indicators of FN-infection. Batty et al. detected FN in seven of 49 (14 %) patients with tonsillitis (including quinsy), but did not compare this finding with culture results from healthy controls [2]. Aliyu et al. [11], using PCR, detected FN DNA in ten of 100 swabs from sore throat patients (two FN-positive patients also had growth of beta-hemolytic streptococci), but in none of 100 controls (mean age 40 years). Jensen et al. [12] detected the presence of FN DNA on 29 (48 %) swabs from patients with non-streptococcal acute tonsillitis, which was significantly more than in the control swabs (21 %). Lastly, Eaton et al. [13] detected FN in 28 of 502 (5.6 %) cultures from tonsillar surface swabs from patients with tonsillitis, but did not compare these findings with culture results from healthy controls. Using conventional culture methods and specific FN agar plates, we detected FN in 16 % of tonsillar surface swabs from acute tonsillitis patients aged 15–40 years and in 9 % from equally aged healthy controls. This trend for higher FN isolation rate among patients with acute infection was statistically insignificant (P = 0.199). In designing the study and the number of patients needed to show the proposed difference in FN isolation rates, we underestimated the frequency of FN colonization in healthy individuals. Hence, the study may be underpowered to reveal a possible difference in FN isolations rates. Another possible inexpediency in our study design is the fact that we included patients aged 15–40 years. A very recent study of patients with peritonsillar abscess showed that FN is much more prevalent in patients aged 15–24 years than patients with other ages [14]. Similar findings have been done in patients with Lemierre’s syndrome [9]. The current study underscores this trend of FN affecting teenagers and young adult most frequently. FN was isolated (almost) significantly more frequently among patients aged 15–29 years (24 %) compared to equally aged healthy controls (9 %). On the contrary, patients aged 30–40 years and equally aged controls had similar FN recovery rates (10 vs 8 %). Our findings in healthy subjects confirm that FN can be part of the normal oropharyngeal flora and stress that the detection of FN in tonsillar surface swabs should be interpreted with caution. Another limitation of the study is that viral etiology was conceived in patients without recovery of the defined
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Table 2 Clinical and biochemical characteristics of 100 patients with acute tonsillitis stratified by bacterial findings Variables
Fusobacterium necrophorum
Fusobacterium necrophorum ? betahemolytic streptococcus
Group A streptococcus
Group C/G streptococcus
Mixed oral floraa
No of patients
12
4
26
10
48
No of men
9 (75 %)
3 (75 %)
3 (12 %)
3 (30 %)
13 (27 %)
Pb
Pc
Patient data
Age (years)
26 (15–36)
No of smokers
2 (17 %)
29 (24–35) 0 (0 %)
33 (18–40) 5 (19 %)
25 (16–38) 0 (0%)
27 (15–39) 7 (15 %)
0.001d
0.005e
f
0.593g
d
1.000e
h
0.001 0.565
4 (1–21)
3 (2–4)
3 (1–14)
3 (1–6)
5 (1–21)
0.043
0.569h
Per-oral temperature (°C)
36.8 (36.5–37.0)
37.3 (36.6–37.9)
37.1 (36.9–37.3)
37.0 (36.6–37.3)
36.7 (36.5–36.8)
0.004f
0.472g
Positive streptococcal antigen testi
0 (0 %)
3 (75 %)
23 (88 %)
0 (0 %)
2 (4 %)
\0.001d
1.000e
0.03 (0.02–0.40)
0.18 (0.02–0.38)
0.04 (0.02–0.09)
0.04 (0.02–0.75)
0.03 (0.02–0.51)
0.189h
0.180h
12 (6–28)
43 (7–284)
24 (15–38)
6 (2–17)
6 (4–8)
\0.001f
0.178g
f
Symptom duration (days) Clinical tests
Infection markers Procalcitonin (lg/l) C-reactive protein (mg/l) 9
White blood cell count (10 /l)
8.9 (7.2–10.7)
13.4 (6.6–20.3)
10.9 (9.6–12.1)
9.2 (7.1–11.4)
7.7 (6.8–8.5)
\0.001
0.184g
Absolute neutrophil count (109/ l)
5.0 (3.3–6.7)
8.5 (0.1–17.0)
8.4 (7.2–9.5)
6.6 (4.1–9.0)
4.8 (4.0–5.7)
\0.001f
0.830g
6 (50 %)
0 (0 %)
2 (8 %)
2 (20 %)
22 (46 %)
0.004d
1.000e
19 (40 %)
d
0.185e
d
Total Centor score Score 1 Score 2
2 (17 %)
2 (50 %)
10 (38 %)
6 (60 %)
0.333
Score 3
4 (33 %)
2 (50 %)
14 (54 %)
2 (20 %)
7 (15 %)
0.007
0.206e
Score 4
0 (0 %)
0 (0 %)
0 (0 %)
0 (0 %)
0 (0 %)
–
–
0 (0 %)
0 (0 %)
0 (0 %)
0 (0 %)
1 (2 %)
0.859d
1.000e
d
0.754e
d
0.756e
d
1.000e
Distribution of Centor’s criteria Oral temperature C38.3 °C Tonsillar exudate Absence of cough Enlarged cervical lymph nodes
6 (50 %) 7 (58 %) 9 (75 %)
4 (100 %) 4 (100 %) 2 (50 %)
21 (81 %) 22 (85 %) 21 (81 %)
5 (50 %) 5 (50 %) 10 (100 %)
21 (44 %) 25 (52 %) 34 (71 %)
0.012 0.028
0.225
Means (CI 95 %) are given for age, oral temperature, C-reactive protein, white blood cell count, and absolute neutrophil count. Medians (range) are given for symptom duration and procalcitonin a Mixed oral flora refers to light to moderate growth of viridans streptococci, Neisseria species, Lactobacillus species, coagulase-negative staphylococci, Prevotella species, and Fusobacterium non-necrophorum alone or in mixture b
All pathogens
c
Fusobacterium necrophorum vs mixed oral flora
d
Chi square test
e
Fisher’s exact test
f
Analyse of variance (ANOVA)
g
Student’s t test
h i
Kruskal–Wallis test Microbiological culture results were used as standard of reference
bacterial tonsillar pathogens, but no viral studies were performed to confirm that belief. We found no differences in Centor score and the individual symptoms and findings between patients growing FN, group C/G streptococci, and mixed oral flora. Hence, the Centor score does not seem to be useful to estimate the likelihood of FN-positive acute tonsillitis.
We found no differences in the mean values of PCT, CRP, WBC, and ANC between patients growing FN and mixed oral flora. Hence, infection markers were not useful in the detection of FN-positive acute tonsillitis. Furthermore, the infection markers were only modestly affected by the clinical infection in both patients with growth of FN, group C/G streptococci, and mixed oral flora, which may
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Table 3 Associations between Centor score, semi-quantitative growth, and infection markers in patients with Fusobacterium necrophorumpositive acute tonsillitis Semi-quantitative growth
Infection markers
?1
?2
?3
?4
Procalcitonin (lg/l)
C-reactive protein (mg/l)
White blood cell count (9109/l)
Absolute neutrophil count (9109/l)
Centor score 2
–
1 (50 %)
0 (0 %)
1 (50 %)
0.02 (0.02–0.02)
3 (0–29)
7.0 (0.3–13.7)
3.6 (0–15.7)
Centor score 3
–
0 (0 %)
2 (50 %)
2 (50 %)
0.2 (0–0.4)
25 (0–59)
10.7 (6.9–14.4)
4.3 (0–9.7)
Centor score 4
–
–
–
–
–
–
–
–
Procalcitonin (lg/ l)
–
0.05 (0–0.45)
0.12 (0–0.42)
0.07 (0–0.13)
C-reactive protein (mg/l)
–
16 (0–154)
26 (0–53)
17 (1–33)
White blood cell count (9109/l)
–
9.1 (0–28.5)
9.2 (6.3–12.1)
8.8 (4.8–12.7)
Absolute neutrophil count (9109/l)
–
6.2 (0–26.3)
5.4 (0.7–10.2)
4.4 (1.4–7.4)
Infection markers
Means (CI 95 %) are given for C-reactive protein, white blood cell count, and absolute neutrophil count Median (range) is given for procalcitonin
reflect the relatively localized tonsillar infection. In a previous study from our institution, we found that FN-positive patients with peritonsillar abscess had significantly higher mean levels of CRP and ANC compared to peritonsillar abscess patients with other bacterial findings [8]. In two case reports of patients with FN-positive acute tonsillitis, high levels of CRP (121 mg/l) [15] and WBC (10–16 9 109/l) [15, 16] were found. However, the two patients were admitted to hospital whereas our patients were primary consultations in general practice without any patients being referred to hospital. We found no correlations between the mean levels of infection markers, the Centor score, and the (semi-) quantitative growth of FN. Furthermore, unlike two previous studies using real-time PCR, we found no difference in quantitative growth of FN between patients and controls [11, 12]. Interestingly, we found highly elevated infection markers, heavy semi-quantitative growth patterns, and high Centor scores in patients with co-finding of FN and beta-hemolytic streptococci. Previous studies have pointed to synergism between FN and other bacteria (including group C/G streptococci) [12, 17]. However, Gehrt et al. [18] noted that isolation of FN in acute tonsillitis patients was negatively correlated with the detection of GAS. It has been proposed that the interaction of FN with other microorganisms increases the permeability of the tissue which facilitates the penetration of FN and thus provides access to anaerobic growth conditions in the deeper layers of tissue [3]. We found that male acute tonsillitis patients were significantly more often FN positive compared to females.
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Hagelskjaer et al. [19] noted that FN-positive acute tonsillitis was observed more often in females than in males among teenagers under the age of 17 years, whereas males dominated in older age groups. Eaton et al. [13] isolated FN most frequently in tonsillitis patients aged 10–29 years, and observed a higher FN incidence rate among girls aged 10–19 years compared to boys at the same age. Furthermore, males were more frequently infected with FN in the age group 20–29 years. Similarly, the incidence rate of peritonsillar abscess was significantly higher in girls aged 13–14 years compared to boys at the same age, but subsequently males had higher incidence rates than females and this was statistically significant for the age groups 20–29 years and 40–49 years [14]. Amess et al. [3] found an equal male/female ratio among patients with FN-associated sore throat. A recent study from our institution found that smoking was associated with significantly increased risk of peritonsillar abscess in both males and females of all age, and that there was no difference in the microbiological flora between smokers and non-smokers [20]. In the current study, we found no association between individual bacteria and smoking habits in patients with acute tonsillitis.
Conclusion The current study stresses that FN is a part of the normal oropharyngeal flora and that culture results regarding FN
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should be interpreted with caution. We found a strong trend for higher isolation rates of FN in younger (15–29 years) patients with acute tonsillitis compared to equally aged healthy controls, and FN is likely to be a significant and prevalent pathogen among young adults with uncomplicated acute tonsillitis. This finding seems clinically very important as these teenagers and young adults are at the highest risk of abscess development with FN and timely diagnosis and antibiotic treatment may avoid suppurative complications. The Centor score, individual symptoms and clinical findings, infection markers, and semi-quantitative growth patterns do not seem to be of value in the detection of FN-positive patients with acute tonsillitis. Acknowledgments The authors are thankful to Skoedstrup general practice, 8541 Skoedstrup, Denmark for providing facilities available in the recruitment of patients. Conflict of interest of interest.
The authors declare that they have no conflict
Ethical approval All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
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