Eur J Clin Microbiol Infect Dis (2015) 34:1533–1537 DOI 10.1007/s10096-015-2382-1
ARTICLE
Burkholderia gladioli infection isolated from the blood cultures of newborns in the neonatal intensive care unit F. Zhou 1 & H. Ning 2 & F. Chen 1 & W. Wu 1 & A. Chen 1 & J. Zhang
3
Received: 13 February 2015 / Accepted: 31 March 2015 / Published online: 30 April 2015 # Springer-Verlag Berlin Heidelberg 2015
Abstract Burkholderia gladioli was described as a plant pathogen, and it is a rare cause of infection in humans that is primarily associated with human pulmonary infections, such as chronic granulomatous disease and cystic fibrosis. The neonatal respiratory system is not fully developed and cannot expel bacterial aerosol properly. A total of 2,676 newborns in the neonatal intensive care unit were retrospectively analysed in Putian City, Fujian Province, China, from 2011 to 2014. All of the blood samples were tested for C-reactive protein (CRP), procalcitonin (PCT) and white blood cell (WBC). B. gladioli infections were determined and analysed using a blood culture system. Antibiotic susceptibility testing was performed using the K-B method. Of the 2,676 participants, 87 (3.25 %) had a positive B. gladioli blood culture that occurred >72 h after birth, including a premature group (54.0 %, asphyxia [vs. * J. Zhang [email protected] F. Zhou [email protected] H. Ning [email protected] F. Chen [email protected] W. Wu [email protected] A. Chen [email protected] 1
Department of Clinical Laboratory, Fujian Medical University Teaching Hospital, First Hospital of Putian, Putian 351100, China
2
The Workers and Staff Hospital of HangZhou Steel Group Corp., Hangzhou 310022, China
3
The People’s Hospital of Yuxi, Yuxi, Yunnan 653100, China
9.20 %], fever [vs. 13.80 %], pneumonia [vs. 6.90 %] and hyperbilirubinaemia [vs. 8.05 %]) and newborns with necrotising enterocolitis (NEC) (vs. 5.75 %). The mean±standard deviation (SD) of the CRP level was 12.31±0.26 mg/L and that of the PCT level was 1.53±0.21 ng/ml in the 87 B. gladioli-infected newborns. Most of the B. gladioli isolates were sensitive to many antimicrobial agents and did not lead to serious consequences. All of the B. gladioli-infected newborns were unhealthy, especially the premature infants. B. gladioli might be a causative bacteraemia agent in neonates, it appears to have pathogenic potential in newborns and its sensitivity to antibiotics may be a beneficial factor.
Introduction Burkholderia gladioli is a Gram negative, non-fermenting rod that is closely related to the Pseudomonas genus. Additionally, it grows on MacConkey agar and on basal media at 35 °C [1]. B. gladioli has been described for a decade, during which time it has spread to more plants and has occasionally infected humans [2, 3]. Although reports of human infections are rare, the cocovenenans pathovar of B. gladioli appears to be responsible for the majority of human infection cases [4, 5], and its lethality was shown to be especially high in newborns that were severely immunocompromised or premature [6]. B. gladioli can easily be neutralised by human antibodies and complement factors; therefore, most healthy people are protected from infection [7, 8]. In the clinical laboratory, B. gladioli has been isolated from blood cultures. The absence of protective serum factors in unhealthy newborns leads to B. gladioli infections and an increased mortality rate in unhealthy newborns. In this study, we collected 2,676 blood samples from newborns in neonatal wards from June 2011 to June 2014, and a total of 139 newborns had a
1534
Eur J Clin Microbiol Infect Dis (2015) 34:1533–1537
positive blood culture at their initial admission. Most of the 139 neonates were unhealthy or premature; 87 (3.25 % of the total blood samples) of the 139 newborns had a positive B. gladioli blood culture that occurred >72 h after birth. We analysed the serum C-reactive protein (CRP) and procalcitonin (PCT) levels of these 87 newborns, compared the CRP and PCT biomarker results, and found that the levels of CRP and PCT were above the normal levels, and the 87 newborns may be infected by B. gladioli. Fortunately, B. gladioli is drug-sensitive, and it did not lead to serious consequences.
Table 2
The primary diagnoses of the 87 newborns Total (n)
%
Premature
47
Asphyxia/premature + asphyxia
5/3
54.0 9.20
Fever/premature + fever Pneumonia/premature + pneumonia
8/4 4/2
13.80 6.90
Hyperbilirubinaemia NEC
7 5
8.05 5.75
Premature + congenital heart disease
2
2.30
Total
87
100
Methods
NEC necrotising enterocolitis
Participants and hospital settings
undergone, antibiotic susceptibility, and treatment outcomes. Vaginal cultures from the neonate’s mothers were also collected. Nosocomial sepsis was defined as a bloodstream infection that occurred >72 h after NICU admission. We defined the infection-specific mortality as within 14 days of a positive blood culture result.
The study was conducted in Putian City, Fujian Province, China, from June 2011 through June 2014. All newborns were born and inpatients in the newborn wards of the First Hospital of Putian City, a 1,200-bed tertiary care government hospital. The subjects were recruited consecutively using convenience sampling in the neonatal intensive care unit (NICU). Our NICU was composed of three separate units that had 60 beds, with an average of 1,300 annual admissions. We evaluated prospectively collected data from all of the newborns that were admitted to the NICU during the 3-year study period. The purpose and methods of the study were explained to all of the participants’ parents. The Fujian Medical University Teaching Hospital, First Hospital of Putian ethics committee approved the study, and we obeyed the Declaration of Helsinki informed consent procedures, which were carried out individually. Additionally, written consent was obtained from all of the parents before any procedures were performed. Clinical characteristics The clinical characteristics included gestational age, birth weight, NICU admission date, gender, invasive procedures
Bacterial isolates and antimicrobial susceptibility testing The antibiotic choices in our NICU were piperacillin and cefoperazone. The patients were treated until the blood culture results were obtained. During antibiotic treatment of the neonates, liver function, renal function and acute-phase reactants were monitored weekly. Arterial blood was collected by the nurses, using sterilised needles, and it was transferred to the laboratory within 2 h. All of the 2,676 specimens were coded with a unique identification number that was assigned to each newborn. The B. gladioli bloodstream infection determinations were conducted using the BACTEC™ FX (BD) blood culture system. When we found a positive blood culture, all of the B. gladioli strains were tested on blood agar that was inoculated at 35 °C. The extracted bacterial liquids were shipped and analysed on the VITEK 2 Compact platform. All of the blood samples were tested for CRP and PCT levels using a BN™ II
Table 1 Demographics of the study cohort Gestational age (weeks) Birth weight (g) Hours until a positive culture was observed Obtained (h) Mode of delivery
a
Positive culture (n=139)
Positive rate (%)
72 h (Table 1). Of the 87 newborns, the primary diagnoses were congenital anomalies, prematurity with respiratory distress syndrome and pneumonia (Table 2). The inborn neonates with uninfected B. gladioli were not meaningfully different to the infected neonates. Only two newborns died, and the deaths were a result of severe congenital diseases. The mortality rate was 1.44 % (2.30 %). The premature group (54.0 %) had significantly higher rates of the following compared with the other groups: asphyxia (vs. 9.20 %), fever (vs. 13.80 %), pneumonia (vs. 6.90 %), hyperbilirubinaemia (vs. 8.05 %) and necrotising enterocolitis (NEC) (vs. 5.75 %) (p
ARTICLE
Burkholderia gladioli infection isolated from the blood cultures of newborns in the neonatal intensive care unit F. Zhou 1 & H. Ning 2 & F. Chen 1 & W. Wu 1 & A. Chen 1 & J. Zhang
3
Received: 13 February 2015 / Accepted: 31 March 2015 / Published online: 30 April 2015 # Springer-Verlag Berlin Heidelberg 2015
Abstract Burkholderia gladioli was described as a plant pathogen, and it is a rare cause of infection in humans that is primarily associated with human pulmonary infections, such as chronic granulomatous disease and cystic fibrosis. The neonatal respiratory system is not fully developed and cannot expel bacterial aerosol properly. A total of 2,676 newborns in the neonatal intensive care unit were retrospectively analysed in Putian City, Fujian Province, China, from 2011 to 2014. All of the blood samples were tested for C-reactive protein (CRP), procalcitonin (PCT) and white blood cell (WBC). B. gladioli infections were determined and analysed using a blood culture system. Antibiotic susceptibility testing was performed using the K-B method. Of the 2,676 participants, 87 (3.25 %) had a positive B. gladioli blood culture that occurred >72 h after birth, including a premature group (54.0 %, asphyxia [vs. * J. Zhang [email protected] F. Zhou [email protected] H. Ning [email protected] F. Chen [email protected] W. Wu [email protected] A. Chen [email protected] 1
Department of Clinical Laboratory, Fujian Medical University Teaching Hospital, First Hospital of Putian, Putian 351100, China
2
The Workers and Staff Hospital of HangZhou Steel Group Corp., Hangzhou 310022, China
3
The People’s Hospital of Yuxi, Yuxi, Yunnan 653100, China
9.20 %], fever [vs. 13.80 %], pneumonia [vs. 6.90 %] and hyperbilirubinaemia [vs. 8.05 %]) and newborns with necrotising enterocolitis (NEC) (vs. 5.75 %). The mean±standard deviation (SD) of the CRP level was 12.31±0.26 mg/L and that of the PCT level was 1.53±0.21 ng/ml in the 87 B. gladioli-infected newborns. Most of the B. gladioli isolates were sensitive to many antimicrobial agents and did not lead to serious consequences. All of the B. gladioli-infected newborns were unhealthy, especially the premature infants. B. gladioli might be a causative bacteraemia agent in neonates, it appears to have pathogenic potential in newborns and its sensitivity to antibiotics may be a beneficial factor.
Introduction Burkholderia gladioli is a Gram negative, non-fermenting rod that is closely related to the Pseudomonas genus. Additionally, it grows on MacConkey agar and on basal media at 35 °C [1]. B. gladioli has been described for a decade, during which time it has spread to more plants and has occasionally infected humans [2, 3]. Although reports of human infections are rare, the cocovenenans pathovar of B. gladioli appears to be responsible for the majority of human infection cases [4, 5], and its lethality was shown to be especially high in newborns that were severely immunocompromised or premature [6]. B. gladioli can easily be neutralised by human antibodies and complement factors; therefore, most healthy people are protected from infection [7, 8]. In the clinical laboratory, B. gladioli has been isolated from blood cultures. The absence of protective serum factors in unhealthy newborns leads to B. gladioli infections and an increased mortality rate in unhealthy newborns. In this study, we collected 2,676 blood samples from newborns in neonatal wards from June 2011 to June 2014, and a total of 139 newborns had a
1534
Eur J Clin Microbiol Infect Dis (2015) 34:1533–1537
positive blood culture at their initial admission. Most of the 139 neonates were unhealthy or premature; 87 (3.25 % of the total blood samples) of the 139 newborns had a positive B. gladioli blood culture that occurred >72 h after birth. We analysed the serum C-reactive protein (CRP) and procalcitonin (PCT) levels of these 87 newborns, compared the CRP and PCT biomarker results, and found that the levels of CRP and PCT were above the normal levels, and the 87 newborns may be infected by B. gladioli. Fortunately, B. gladioli is drug-sensitive, and it did not lead to serious consequences.
Table 2
The primary diagnoses of the 87 newborns Total (n)
%
Premature
47
Asphyxia/premature + asphyxia
5/3
54.0 9.20
Fever/premature + fever Pneumonia/premature + pneumonia
8/4 4/2
13.80 6.90
Hyperbilirubinaemia NEC
7 5
8.05 5.75
Premature + congenital heart disease
2
2.30
Total
87
100
Methods
NEC necrotising enterocolitis
Participants and hospital settings
undergone, antibiotic susceptibility, and treatment outcomes. Vaginal cultures from the neonate’s mothers were also collected. Nosocomial sepsis was defined as a bloodstream infection that occurred >72 h after NICU admission. We defined the infection-specific mortality as within 14 days of a positive blood culture result.
The study was conducted in Putian City, Fujian Province, China, from June 2011 through June 2014. All newborns were born and inpatients in the newborn wards of the First Hospital of Putian City, a 1,200-bed tertiary care government hospital. The subjects were recruited consecutively using convenience sampling in the neonatal intensive care unit (NICU). Our NICU was composed of three separate units that had 60 beds, with an average of 1,300 annual admissions. We evaluated prospectively collected data from all of the newborns that were admitted to the NICU during the 3-year study period. The purpose and methods of the study were explained to all of the participants’ parents. The Fujian Medical University Teaching Hospital, First Hospital of Putian ethics committee approved the study, and we obeyed the Declaration of Helsinki informed consent procedures, which were carried out individually. Additionally, written consent was obtained from all of the parents before any procedures were performed. Clinical characteristics The clinical characteristics included gestational age, birth weight, NICU admission date, gender, invasive procedures
Bacterial isolates and antimicrobial susceptibility testing The antibiotic choices in our NICU were piperacillin and cefoperazone. The patients were treated until the blood culture results were obtained. During antibiotic treatment of the neonates, liver function, renal function and acute-phase reactants were monitored weekly. Arterial blood was collected by the nurses, using sterilised needles, and it was transferred to the laboratory within 2 h. All of the 2,676 specimens were coded with a unique identification number that was assigned to each newborn. The B. gladioli bloodstream infection determinations were conducted using the BACTEC™ FX (BD) blood culture system. When we found a positive blood culture, all of the B. gladioli strains were tested on blood agar that was inoculated at 35 °C. The extracted bacterial liquids were shipped and analysed on the VITEK 2 Compact platform. All of the blood samples were tested for CRP and PCT levels using a BN™ II
Table 1 Demographics of the study cohort Gestational age (weeks) Birth weight (g) Hours until a positive culture was observed Obtained (h) Mode of delivery
a
Positive culture (n=139)
Positive rate (%)
72 h (Table 1). Of the 87 newborns, the primary diagnoses were congenital anomalies, prematurity with respiratory distress syndrome and pneumonia (Table 2). The inborn neonates with uninfected B. gladioli were not meaningfully different to the infected neonates. Only two newborns died, and the deaths were a result of severe congenital diseases. The mortality rate was 1.44 % (2.30 %). The premature group (54.0 %) had significantly higher rates of the following compared with the other groups: asphyxia (vs. 9.20 %), fever (vs. 13.80 %), pneumonia (vs. 6.90 %), hyperbilirubinaemia (vs. 8.05 %) and necrotising enterocolitis (NEC) (vs. 5.75 %) (p
