Journal of Antimicrobial Chemotherapy (1990) 26, 549-559
Assessment of the interaction between ciprofloxacin and teicoplanin in vitro and in neutropenic patients C. S. Lewin", S. M. Kelsey*, R. Paton", A. C. Newland* and S. G. B. Amyesr*
The interactions of ciprofloxacin and teicoplanin were investigated against methicillin-sensitive and methicillin-resistant Staphylococcus aureus and Staph. epidermidis isolated during a clinical trial of the efficacy of this combination. In-vitro studies of the combination of ciprofloxacin and teicoplanin found no evidence of any antagonism between these two drugs in terms of inhibition of bacterial multiplication, as determined by Fractional Inhibitory Concentration Indices, and lethality. Ginical use of teicoplanin plus ciprofloxacin as empirical therapy in 29 febrile neutropenic patients revealed an overall response rate of 75%. Response rate for staphylococcal infections, which accounted for 53% of isolated pathogens, was 80%. No serious adverse drug reactions were seen. Our results show that both in vitro, and in the treatment of febrile neutropenic patients, teicoplanin plus ciprofloxacin is an effective anti-staphylococcal combination. Introduction Ciprofloxacin is often used in combination with a second agent when empirically treating febrile episodes in neutropenic patients, primarily to increase anti-staphylococcal and anti-streptococcal activity. The addition of the second drug may prevent the emergence of resistant organisms during therapy. The combination of ciprofloxacin with either benzylpenicillin or vancomycin has been effective in treating febrile episodes in neutropenic patients (Smith et al., 1988; Kelsey et al., 1990). Teicoplanin is a glycopeptide antibiotic structurally similar to vancomycin acting by inhibiting the polymerisation of peptidoglycan. Teicoplanin, in common with vancomycin, possesses good anti-staphylococcal and anti-streptococcal activity (Williams & Gruneberg, 1984; Greenwood, 1988). However, initial studies suggest that teicoplanin possesses some advantages over vancomycin in terms of its toxicological and pharmacokinctic properties (Buniva etal., 1988; Smith et al., 1989). In view of the increasing prevalence of Gram-positive organisms as a primary cause of fever and morbidity in neutropenic patients in recent years (Klastersky, 1986), primarily due to the use of long term indwelling central venous catheters, teicoplanin would appear to have potential for use in combination with ciprofloxacin when treating febrile episodes in immunocompromised patients. If two antibacterial agents are to be used successfully in combination no antagonism must occur. It was therefore decided to investigate the interactions of ciprofloxacin and teicoplanin against staphylococci by the MIC chequerboard technique. The bactericidal activity of an antibacterial (or combination 549 0305-7453/90/100549+ 11 $02.00/0
© 1990 The British Society for Antimicrobial Chemotherapy
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'Department of Bacteriology, Medical School, University of Edinburgh, Teviot Place, Edinburgh EH8 9AG;bDepartment of Haematology, The London Hospital, Whitechapel, London El IBB, UK
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C. S. Lewin et al.
of antibacterial agents) is particularly important when treating immunocompromised patients. Therefore, the effect of teicoplanin on the bactericidal activity of ciprofloxacin was also investigated as some antibacterials, which MIC studies indicate have no interaction with the 4-quinolones, can affect their bactericidal activities (Lewin & Smith, 1989). A clinical study, to investigate the use of teicoplanin and ciprofloxacin in combination for the empirical treatment of febrile neutropenic patients was also performed. The efficacy of this combination in treating Gram-positive infections in these patients is reported.
Ciprofloxacin (Bayer UK) and teicoplanin (Merrell Dow, UK) were dissolved in sterile distilled water. The laboratory strains Staphylococcus aureus NCTC6751, Staph. aureus E3T and Staph. epidermidis SK360 (Lewin & Amyes, 1989) were used. Clinical isolates of methicillin-sensitive staphylococci were obtained from the Royal Infirmary Edinburgh. Methicillin-resistant Staph. aureus (MRSA) isolates were obtained from St Thomas' Hospital, London. The Staph. epidermidis strains were isolated during the clinical study at the London Hospital. Minimum inhibitory concentrations Minimum inhibitory concentrations (MICs) and fractional inhibitory concentrations (FICs) were determined by the serial dilution method in Isosensirest agar (Oxoid, UK) with an inoculum of 104cfu. The MIC was taken to be the lowest drug concentration that inhibited bacterial growth after an overnight incubation of the plates at 37°C. The FIC was taken as the proportion of the MIC of the test drug, in the presence of the other, to give no visible growth and the FIC Index was the sum of the FICs of the two drugs at maximum interaction. An FIC Index of < 0-7 was taken as synergy, 0-7-< 1-5 as addition, 1-5—2-0 as indifference and > 2 0 as antagonism. Determination of antibacterial effects of mixtures of ciprofloxacin and teicoplanin The antibacterial effects of ciprofloxacin and teicoplanin alone, and in combination, against staphylococci in nutrient broth were determined as previously described (Lewin el al., 1989). Survival was estimated by viable counting on nutrient agar. Patients and methods for clinical study A clinical study of the efficacy of teicoplanin plus ciprofloxacin in treating febrile episodes in neutropenic patients was carried out at the London Hospital, Whitechapel. The study was passed by the local ethical committee and all patients gave informed consent. Neutropenic patients with haematological malignancy who became febrile ( >38-5°C once or >380°C twice 2 h apart, not associated with blood products) were treated empirically with a combination of teicoplanin and ciprofloxacin. Neutropenia was defined as a total neutrophil count of less than 1-Ox lO'/litre. Patients with a history of allergy to the study drugs, or who had received broad-spectrum antibiotics in the previous five days, were excluded from the study. Ciprofloxacin (200 mg) was given intravenously 12-hourIy as a 100 ml infusion over 30min. Teicoplanin was administered as a slow intravenous bolus injection at a dose of 6 mg/kg body weight 12-hourly
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Materials and methods
Interaction of teicopUnin and dproBoxadn
551
Results The MICs of teicoplanin and ciprofloxacin for two laboratory strains, Staph. aureus E3T and Staph. aureus NCTC6751, and three clinical isolates of Staph. aureus from the Royal Infirmary, Edinburgh, were determined. All five strains were sensitive to both drugs (Table I). The FICs of mixtures of ciprofloxacin and teicoplanin against these isolates were also determined and the indices were all between 1 and 2, the mean index being 1-3 (Table I). This indicates that at best there was an additive effect between the two drugs while at worst indifference occurred. However, no antagonism (FIC index > 2 0 ) was detected with mixtures of these two drugs. Six MRSA were also examined. There was no difference in the susceptibilities of the MRSAs to ciprofloxacin and teicoplanin as compared to the methicillin-sensitive Staph aureus (MSSA) isolates (Table I). As with the MSSA, the FIC indices of the MRSA were all between 1 and 2 (mean FIC index, 1-4) indicating that although no synergy occurred between these two compounds neither was there any antagonism (Table I). Hence, the combination of teicoplanin and ciprofloxacin should be effective against both MSSA and MRSA. Nine Staph. epidermidis, the laboratory strain Staph. epidermidis SK36O and eight strains of Staph. epidermidis isolated during the clinical trial at the London Hospital were investigated. The MIC of teicoplanin for all the strains was slightly higher than that observed for the Staph. aureus (Table I). The MIC of ciprofloxacin of most of the
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for two doses followed by 6mg/kg every 24 h thereafter. All patients received gut decontamination with oral co-trimoxazole 960 mg twice daily and colistin 1 -5 megaunits twice daily, and an oral antifungal agent. These drugs were continued during the febrile episode. Full haematological, biochemical and microbiological assessment was made at entry to the study and at regular intervals during therapy. Relevant microbiological assessment was repeated on cessation or modification of study antibiotic therapy. Patients were reviewed daily and initial evaluation was made at 72 h of treatment. Antibiotics were continued until the patient had been apyrexial for 72 h. Antibiotic therapy was changed or modified if either (a) a pathogen resistant to both study antibiotics was isolated; (b) deterioration in the patients clinical state was thought to be infectionrelated; (c) there was no clinical improvement after 72 h therapy. Febrile episodes were classified as microbiologically documented, clinically documented or pyrexia of unknown origin (PUO). Evaluation of response to antibiotic therapy was made at 72 h and at either discontinuation or modification of therapy. There were four categories of clinical response; (1) complete resolution—disappearance of all infection-related symptoms and signs; (2) improvement—disappearance of fever with persistence of other signs of infection, or resolution of signs of infection with persistent fever; (3) failure—little or no improvement in signs or symptoms of infection such that modification of antibiotic therapy was required, or withdrawal of one or both study drugs due to drug-induced toxicity; (4) indeterminate—any patient dying a noninfective death before evaluation of antibiotic therapy could be performed. Microbiologically documented infections were classified at final evaluation as either eradicated, persistent, or indeterminate if follow-up cultures could not be obtained. Superinfections were defined as presence of a new organism judged to be causing an infectious process during, or at the end, of study drug therapy.
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Table L Minimum inhibitory concentrations (MIC) and fraction inhibitory concentration (FIC) indices of ciprofloxacin and teicoplanin
Bacterial strain
MIC (mg/1) ciprofloxacin teicoplanin
FIC index
0-5 10 10 20 10
0-12 0-25 0-5 0-5 0-25
20 1-25 1-5 10 1O
Methicillin-resistant Staph. aureus S113 MRSA 1 MRSA6 MRSA 23 MRSA 25 MRSA 27
0-5 20 10 10 20 0-5
0-5 05 0-5 0-25 0-5 05
20 10 1-25 10 10 20
Methicillin-sensitive coagulase-negative staphylococci Staph. epidermidis SK360 Staph. epidermidis-B6&3 Staph. epidermidis B9226 Staph. epidermidis B70 Staph. epidermidis B567 Staph. epidermidis B566 Staph. epidermidis B280 Staph. epidermidis B47 Staph. epidermidis B603
40 40 40 10 40 80 80 80 20
025 025 025 025 05 05 025 20 05
1-5 1-5 10 075 10 10 1-5 1-5 075
isolates was similar to that observed for the Staph. aureus isolates. The FIC indices of mixtures of the two drugs were between 0-75 and 1-5 indicating an additive effect. Hence all 20 of the staphylococcal isolates tested were sensitive to both ciprofloxacin and teicoplanin and mixtures of the two drugs were found to be either additive or indifferent. With the 4-quinolones, MICs only provide information on the inhibition of bacterial multiplication. Ciprofloxacin not only inhibits bacterial multiplication but is bactericidal to staphylococci in nutrient broth (Figure 1). Ciprofloxacin displayed a biphasic response against Staph. aureus E3T and Staph. epidermidis SK36O, with an optimum killing concentration of 3 mg/1 for both species (Figure 1). The bactericidal activity of teicoplanin was also investigated against both of these species in nutrient broth. Teicoplanin was also found to be bactericidal to both species over three hours at clinically achievable concentrations (Figure 2). However, teicoplanin did not display a biphasic response: the degree of kill was concentration dependent. The bactericidal activity of mixtures of teicoplanin and ciprofloxacin against these two species was then investigated by observing the effect of increasing teicoplanin concentrations on the bactericidal activity of a static concentration of ciprofloxacin against Staph. aureus E3T and Staph. epidermidis SK360 in nutrient broth.
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Methicillin-sensitive Staph. aureus NCTC 6571 E3T 10B14 10B33 10B57
Interaction of teicoplanin and dprofloxadn
553
1000
I 10 Ciprofloxacin (mg/L)
100
Figure 1. Tbe effect of ciprofloxacin on the survival of Staph. aureus E3T ( # ) and Siaph epulermidis SK36O (O) 'n nutrient broth. Slaph. aureus E3T and Slaph. tpidermidis SKJ60 were exposed to various concentrations of ciprofloxacin in nutrient broth. After 3 h incubation at 37°C, percentage survival was estimated by viable counting on nutrient agar.
When teicoplanin was added to ciprofloxacin at its optimum killing concentration of 3 mg/1 no reduction in the amount of kill occurred as the teicoplanin concentration in the mixture increased (Figure 3). If anything, the bactericidal activity increased as the concentration of teicoplanin in the mixture rose. The effect of increasing concentrations of ciprofloxacin on the bactericidal of a clinically achievable teicoplanin concentration 10 mg/1 was also determined. Teicoplanin (10 mg/1), on its own, was bactericidal and a slight increase in the bactericidal activity of the mixtures occurred as the concentration of 4-quinolone in the mixtures rose (Figure 4). Hence, there does not appear to be a reduction in the bactericidal activity of mixtures of ciprofloxacin and teicoplanin as the amount of kill observed with mixtures of the two drugs was no less than that observed when either drug was used alone. Results of the clinical study Twenty nine febrile, neutropenic patients were treated with teicoplanin and ciprofloxacin in the 12 months up to December 1989. Twenty-eight were evaluated for efficacy; one patient withdrew consent after one day of therapy. Mean patient age was 33 ±12 years and mean duration of therapy with trial antibiotics was 7±3 days. None of the patients in this study suffered from renal impairment. There were 18 (64%) microbiologically documented infections (all bacteraemias), three (11%) clinically documented infections (throat, chest, Hickman line skin entry site) and seven (25%) PUOs. Nineteen primary pathogens were isolated from the 18 microbiologically documented infective episodes. 15 (79%) were Gram-positive organisms of which ten (53%) were Staph. epidermidis (Table II).
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•I
554
C. S. Lewin el at.
100
Figure 2. The effect of teicoplanin on the survival of Staph. aureus E3T ( • ) and Slaph epidermidis SK.360 (O) in nutrient broth. Staph. aureus E3T and Slaph. epidermidis SK.360 were exposed to various concentrations of teicoplanin in nutrient broth. After 3 h incubation at 37°C, percentage survival was estimated by viable counting on nutrient agar.
At final clinical evaluation of therapy, 20 (71%) of the 28 febrile episodes had resolved, one (4%) had improved and six (21%) failed to resolve. One patient could not be evaluated clinically because of coexistent cytomegalovirus pneumonia. Three patients (11%) responded with concomitant recovery of their neutrophil count to 1 x 109/!. When the 17 clinically evaluated, microbiologically documented infections were considered separately 13 (76%) clinically resolved, one (6%) improved and three (18%) had failed to resolve. Two failures were in episodes where the primary pathogen was Staph. epidermidis; one of these developed an Aspergillus fumigatus pneumonia which caused deterioration of his clinical state while the other patient required modification of therapy after 96 h because of persistent fever but subsequently responded to a second line antibiotic combination of vancomycin and ceftazidime. For Gram-positive infections, therefore, clinical resolution of fever occurred in 12 (80%) cases with only two cases (13%) failing to respond (Table II). A similar response rate (80%) was seen for staphylococcal infections. Microbiological evaluation of documented infections revealed that infecting pathogens were eradicated in 11 (61%) episodes while only two (11%) persisted. Follow up cultures were not obtained in five cases (28%) making outcome indeterminate. The persisting organism in one case was Candida tropicalis and in the other Enterobacter cloacae. No Gram-positive organisms were documented to have persisted following study antibiotic therapy (Table II).
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I 10 Tetcoplanln (mg/L)
Interaction of tekoplanin and dprofloxacin
555
100
100
Figure 3, The influence of teicoplanin on the survival of Slaph. aweus E3T ( • ) and Slaph. epidermidis SK.360 (O) treated with a fixed concentration of dprofloxadn. Staph. aweus E3T and Slaph. epidermidis SK.360 were exposed to dprofloxadn (3 mg/1) alone or in the additional presence of various concentrations of teicoplanin, in nutrient broth. After 3 h incubation at 37°C, percentage survival was estimated by viable counting on nutrient agar. 100
01 I Clprofloiocln (mg/l)
10
Figure 4. The influence of dprofloxadn on the survival of Slaph. aureus E3T ( • ) and Slaph. epidermidis SK360 (O) treated with a fixed concentration of teicoplanin. Slaph. aureus E3T and Staph. epidermidis SK36O were exposed to tekoplanin (10 mg/0 alone or in the additional presence of various concentrations of dprofloxadn, in nutrient broth. After 3 h incubation at 37°C, percentage survival was estimated by viable counting on nutrient agar.
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I 10 Teicoplanin (mg/l)
1
14°
19
Total
"One Sir. sanguis infection was clinically unevaluable (see text).
0 0 0 0 1 0 0 0
8 2 1* 1 0 1 1 0 3
2 0 0 0 0 0 0 1
Clinical treatment results failed resolved improved
10 2 2 1 1 1 1 1
No. of cases
Staph. epidermidis Enterococcus sp. Streptococcus sanguis Str. viridans Escherichia coli Pseudomonas spp. Enterobacter cloacae C. tropkalis
Bacterial Strain
13
0
8 1 1 1 1 1 0
eradicated
2
0 0 0 0 0 0 1 1
4
2 1 1 0 0 0 0 0
Microbiological results indeterminate persisted
Table II. Clinical and microbiological outcome for all microbiologically documented infections
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2 &
(A
P
Interaction of tefcopJanln and dprofloxacln
557
Discussion The interaction of ciprofloxacin and teicoplanin against staphylococci, including isolates from a clinical trial, was investigated and no antagonism could be found between the two drugs in terms of the FIC indices. In agreement with the results of other investigators (Watt, 1989) the two drugs, in combination, were either additive or indifferent. The mixture of teicoplanin and ciprofloxacin was found to be as effective against MRSA as it was against MSSA. This is particularly significant considering the high levels of ciprofloxacin resistance reported in MRSA (Hawkey, 1989; Schaefler, 1989; Lewin, Allen & Amyes, 1990) as the combination of ciprofloxacin with teicoplanin may serve to prevent the emergence of resistant organisms. Investigation of the bactericidal activity of mixtures of the two drugs again found no evidence to indicate any antagonism of the killing activity against staphylococci. Hence these in-vitro studies could not find any evidence of antagonism occurring between these two classes of drugs suggesting that the combination of ciprofloxacin and teicoplanin should be effective clinically. Our preliminary clinical investigations suggest that ciprofloxacin and teicoplanin in combination are effective in treating staphylococcal infections in neutropenic patients. Our data reveal that, when used empirically, 80% of Gram-positive infections resolved with this regimen and 75% of febrile episodes overall either resolved or improved. This response rate corresponds favourably with that of 80% obtained when teicoplanin was used in a triple regimen with amikacin and ceftazidime to treat febrile neutropenic patients after chemotherapy (Del Favero et al., 1987). In our study only two Gram-positive infections, both caused by Staph. epidermidis, failed to resolve with teicoplanin and ciprofloxacin, although in only one case was clinical failure possibly due to persistence of staphylococcal bacteraemia. Previous studies using antibiotic regimens containing teicoplanin to treat staphylococcal infection have recorded failure rates of 8% in immunocompetent hosts (Lewis, Garaud & Parenti, 1988) and 10% for neutropenic hosts (Menichetti et al., 1988); failure of clinical response in these studies correlates poorly with in-vitro sensitivity of the pathogens to teicoplanin and, in many cases, is associated with eradication of the isolated organism. No severe antibiotic-associated adverse reactions were recorded in our study. In
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There were two documented superinfections in patients while receiving teicoplanin and ciprofloxacin. One patient developed aspergillus pneumonia and another a Candida spp. pneumonia. Two further patients had recrudescences of fever while receiving study antibiotics, which only resolved when amphotericin B was administered intravenously although no superinfecting pathogens were isolated. A further patient grew Staph. epidermidis from Hickman line blood 12 h after stopping teicoplanin suggesting persisting line colonization with this organism despite therapy. However, in no case were Hickman lines removed because of infection. AH infections that were thought to be line-associated were treated with antibiotics only. Adverse reactions, possibly related to antibiotic therapy, were noted in seven (24%) cases. Five of these were mild (less than twice normal) rises in liver aspartate and alanine transaminases. One patient developed mild hyperbilirubinaemia and one a rise in serum liver transaminases up to five times the upper limit of normal. In no case did toxicity lead to worsening of the patient's condition or necessitate withdrawal of study antibiotics.
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particular, no nephrotoxicity was observed. Mild, transient derangement of liver transaminase levels, as seen in 24% of our patient group, have previously been recorded following administration of teicoplanin (Lewis et at., 1988) without clinical sequelae. We conclude that teicoplanin with ciprofloxacin is an effective antibacterial combination against staphylococci both in vitro and in neutropenic patients. This provides a useful, nontoxic regimen for the empirical treatment of fever in the immunocompromised host. Acknowledgements
References Buniva, G., Del Favcro, A., Bernareggi, A., Patoia, L. & Palumbo, R. (1988). Pharmacokinetics of MC-tcicoplanin in healthy volunteers. Journal of Antimicrobial Chemotherapy 21, Suppl. A, 23-8. Del Favero, A., Menichetti, F., Guerciolini, R., Bucaneve, G., Baldelli, F., Aversa, F. et al. (1987). Prospective randomized clinical trial of teicoplanin for empiric combined antibiotic therapy in febrile, granulocytopenic acute leukemia patients. Antimicrobial Agents and Chemotherapy 31, 1126-9. Greenwood, D. (1988). Microbiological properties of teicoplanin. Journal of Antimicrobial Chemotherapy 21, Suppl. A, 1-13. Hawkey, P. M. (1989). Where are we now with ciprofloxacin? Journal of Antimicrobial Chemotherapy 24, 477-80. Kelsey, S. M., Wood, M. E., Shaw, E., Jenkins, G. C. & Newland, A. C. (1990). A comparative study of intravenous ciprofloxacin and benzylpenicillin versus nctilmicin and piperacillin for the empirical treatment of fever in neutropenic patients. Journal of Antimicrobial Chemotherapy 25, 149-57. Klastersky, J. (1986). Concept of empiric therapy with antibiotic combinations. American Journal of Medicine 80, Suppl. 5C, 2-12. Lewin, C. S., Allen, R. A. & Amyes, S. G. B. (1990). Potential mechanisms of resistance to the modern fluorinated 4-quinolones. Journal of Medical Microbiology 31, 153-61. Lewin, C. S. & Amyes, S. G. B. (1989.The bactericidal activity of DR-3355, an optically active isomer of ofloxacin. Journal of Medical Microbiology 30, 227-31. Lewin, C. S., Howard, B. M. A., Ratcliffe, N. T. & Smith J. T. (1989). 4-Quinolones and the SOS response. Journal of Medical Microbiology 29, 139-44. Lewin, C. S. & Smith, J. T. (1989). Interactions of the 4-quinolones with other antibacterials. Journal of Medical Microbiology 29, 221-7. Lewis, P., Garaud, J-J. & Parenti, F. (1988). A multicentre open clinical trial of teicoplanin in infections caused by Gram-positive bacteria. Journal of Antimicrobial Chemotherapy 21, Suppl. A, 61-7. Menichetti, F., Del Favero, A., Bucaneve, G., Aversa, F., Baldelli, F., Felicini, R. et al. (1988). Teicoplanin in empirical combined antibiotic therapy of bacteraemias in bone marrow transplant patients. Journal of Antimicrobial Chemotherapy 21, Suppl. A, 105-11. Schaefler, S. (1989). Methicillin-resistant strains of Staphylococcus aureus resistant to quinolones. Journal of Clinical Microbiology 27, 335-6. Smith, G. M., Leyland, M. J., Farrell, I. D. & Geddes, A. M. (1988). A clinical, microbiological and pharmacokinetic study of ciprofloxacin plus vancomycin as initial therapy of febrile episodes in neutropenic patients. Journal of Antimicrobial Chemotherapy 21, 647-55.
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We should like to thank the Clinical and Biomedical Research Committee of the Scottish Home and Health Department for grant no. K/MRS/50/C1135 and Merrell Dow Pharmaceuticals for their support of this investigation.
Interaction of teicoplanin and dprofioxadn
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Smith, S. R., Chcesbrough, J., Spearing, R. & Davies, J. M. (1989). Randomized prospective study comparing vancomycin with teicoplanin in the treatment of infections associated with Hickman catheters. Antimicrobial Agents and Chemotherapy 33, 1193-7. Watt, B. (1989). Interaction of teicoplanin with other antimicrobial agents against Gram-positive aerobes. Journal of Antimicrobial Chemotherapy 23, 657-8. Williams, A. H. & Gruneberg, R. N. (1984). Teicoplanin. Journal of Antimicrobial Chemotherapy 14, 441-5. {Received 16 January 1990; revised version accepted 4 June 1990)
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Assessment of the interaction between ciprofloxacin and teicoplanin in vitro and in neutropenic patients C. S. Lewin", S. M. Kelsey*, R. Paton", A. C. Newland* and S. G. B. Amyesr*
The interactions of ciprofloxacin and teicoplanin were investigated against methicillin-sensitive and methicillin-resistant Staphylococcus aureus and Staph. epidermidis isolated during a clinical trial of the efficacy of this combination. In-vitro studies of the combination of ciprofloxacin and teicoplanin found no evidence of any antagonism between these two drugs in terms of inhibition of bacterial multiplication, as determined by Fractional Inhibitory Concentration Indices, and lethality. Ginical use of teicoplanin plus ciprofloxacin as empirical therapy in 29 febrile neutropenic patients revealed an overall response rate of 75%. Response rate for staphylococcal infections, which accounted for 53% of isolated pathogens, was 80%. No serious adverse drug reactions were seen. Our results show that both in vitro, and in the treatment of febrile neutropenic patients, teicoplanin plus ciprofloxacin is an effective anti-staphylococcal combination. Introduction Ciprofloxacin is often used in combination with a second agent when empirically treating febrile episodes in neutropenic patients, primarily to increase anti-staphylococcal and anti-streptococcal activity. The addition of the second drug may prevent the emergence of resistant organisms during therapy. The combination of ciprofloxacin with either benzylpenicillin or vancomycin has been effective in treating febrile episodes in neutropenic patients (Smith et al., 1988; Kelsey et al., 1990). Teicoplanin is a glycopeptide antibiotic structurally similar to vancomycin acting by inhibiting the polymerisation of peptidoglycan. Teicoplanin, in common with vancomycin, possesses good anti-staphylococcal and anti-streptococcal activity (Williams & Gruneberg, 1984; Greenwood, 1988). However, initial studies suggest that teicoplanin possesses some advantages over vancomycin in terms of its toxicological and pharmacokinctic properties (Buniva etal., 1988; Smith et al., 1989). In view of the increasing prevalence of Gram-positive organisms as a primary cause of fever and morbidity in neutropenic patients in recent years (Klastersky, 1986), primarily due to the use of long term indwelling central venous catheters, teicoplanin would appear to have potential for use in combination with ciprofloxacin when treating febrile episodes in immunocompromised patients. If two antibacterial agents are to be used successfully in combination no antagonism must occur. It was therefore decided to investigate the interactions of ciprofloxacin and teicoplanin against staphylococci by the MIC chequerboard technique. The bactericidal activity of an antibacterial (or combination 549 0305-7453/90/100549+ 11 $02.00/0
© 1990 The British Society for Antimicrobial Chemotherapy
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'Department of Bacteriology, Medical School, University of Edinburgh, Teviot Place, Edinburgh EH8 9AG;bDepartment of Haematology, The London Hospital, Whitechapel, London El IBB, UK
550
C. S. Lewin et al.
of antibacterial agents) is particularly important when treating immunocompromised patients. Therefore, the effect of teicoplanin on the bactericidal activity of ciprofloxacin was also investigated as some antibacterials, which MIC studies indicate have no interaction with the 4-quinolones, can affect their bactericidal activities (Lewin & Smith, 1989). A clinical study, to investigate the use of teicoplanin and ciprofloxacin in combination for the empirical treatment of febrile neutropenic patients was also performed. The efficacy of this combination in treating Gram-positive infections in these patients is reported.
Ciprofloxacin (Bayer UK) and teicoplanin (Merrell Dow, UK) were dissolved in sterile distilled water. The laboratory strains Staphylococcus aureus NCTC6751, Staph. aureus E3T and Staph. epidermidis SK360 (Lewin & Amyes, 1989) were used. Clinical isolates of methicillin-sensitive staphylococci were obtained from the Royal Infirmary Edinburgh. Methicillin-resistant Staph. aureus (MRSA) isolates were obtained from St Thomas' Hospital, London. The Staph. epidermidis strains were isolated during the clinical study at the London Hospital. Minimum inhibitory concentrations Minimum inhibitory concentrations (MICs) and fractional inhibitory concentrations (FICs) were determined by the serial dilution method in Isosensirest agar (Oxoid, UK) with an inoculum of 104cfu. The MIC was taken to be the lowest drug concentration that inhibited bacterial growth after an overnight incubation of the plates at 37°C. The FIC was taken as the proportion of the MIC of the test drug, in the presence of the other, to give no visible growth and the FIC Index was the sum of the FICs of the two drugs at maximum interaction. An FIC Index of < 0-7 was taken as synergy, 0-7-< 1-5 as addition, 1-5—2-0 as indifference and > 2 0 as antagonism. Determination of antibacterial effects of mixtures of ciprofloxacin and teicoplanin The antibacterial effects of ciprofloxacin and teicoplanin alone, and in combination, against staphylococci in nutrient broth were determined as previously described (Lewin el al., 1989). Survival was estimated by viable counting on nutrient agar. Patients and methods for clinical study A clinical study of the efficacy of teicoplanin plus ciprofloxacin in treating febrile episodes in neutropenic patients was carried out at the London Hospital, Whitechapel. The study was passed by the local ethical committee and all patients gave informed consent. Neutropenic patients with haematological malignancy who became febrile ( >38-5°C once or >380°C twice 2 h apart, not associated with blood products) were treated empirically with a combination of teicoplanin and ciprofloxacin. Neutropenia was defined as a total neutrophil count of less than 1-Ox lO'/litre. Patients with a history of allergy to the study drugs, or who had received broad-spectrum antibiotics in the previous five days, were excluded from the study. Ciprofloxacin (200 mg) was given intravenously 12-hourIy as a 100 ml infusion over 30min. Teicoplanin was administered as a slow intravenous bolus injection at a dose of 6 mg/kg body weight 12-hourly
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Materials and methods
Interaction of teicopUnin and dproBoxadn
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Results The MICs of teicoplanin and ciprofloxacin for two laboratory strains, Staph. aureus E3T and Staph. aureus NCTC6751, and three clinical isolates of Staph. aureus from the Royal Infirmary, Edinburgh, were determined. All five strains were sensitive to both drugs (Table I). The FICs of mixtures of ciprofloxacin and teicoplanin against these isolates were also determined and the indices were all between 1 and 2, the mean index being 1-3 (Table I). This indicates that at best there was an additive effect between the two drugs while at worst indifference occurred. However, no antagonism (FIC index > 2 0 ) was detected with mixtures of these two drugs. Six MRSA were also examined. There was no difference in the susceptibilities of the MRSAs to ciprofloxacin and teicoplanin as compared to the methicillin-sensitive Staph aureus (MSSA) isolates (Table I). As with the MSSA, the FIC indices of the MRSA were all between 1 and 2 (mean FIC index, 1-4) indicating that although no synergy occurred between these two compounds neither was there any antagonism (Table I). Hence, the combination of teicoplanin and ciprofloxacin should be effective against both MSSA and MRSA. Nine Staph. epidermidis, the laboratory strain Staph. epidermidis SK36O and eight strains of Staph. epidermidis isolated during the clinical trial at the London Hospital were investigated. The MIC of teicoplanin for all the strains was slightly higher than that observed for the Staph. aureus (Table I). The MIC of ciprofloxacin of most of the
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for two doses followed by 6mg/kg every 24 h thereafter. All patients received gut decontamination with oral co-trimoxazole 960 mg twice daily and colistin 1 -5 megaunits twice daily, and an oral antifungal agent. These drugs were continued during the febrile episode. Full haematological, biochemical and microbiological assessment was made at entry to the study and at regular intervals during therapy. Relevant microbiological assessment was repeated on cessation or modification of study antibiotic therapy. Patients were reviewed daily and initial evaluation was made at 72 h of treatment. Antibiotics were continued until the patient had been apyrexial for 72 h. Antibiotic therapy was changed or modified if either (a) a pathogen resistant to both study antibiotics was isolated; (b) deterioration in the patients clinical state was thought to be infectionrelated; (c) there was no clinical improvement after 72 h therapy. Febrile episodes were classified as microbiologically documented, clinically documented or pyrexia of unknown origin (PUO). Evaluation of response to antibiotic therapy was made at 72 h and at either discontinuation or modification of therapy. There were four categories of clinical response; (1) complete resolution—disappearance of all infection-related symptoms and signs; (2) improvement—disappearance of fever with persistence of other signs of infection, or resolution of signs of infection with persistent fever; (3) failure—little or no improvement in signs or symptoms of infection such that modification of antibiotic therapy was required, or withdrawal of one or both study drugs due to drug-induced toxicity; (4) indeterminate—any patient dying a noninfective death before evaluation of antibiotic therapy could be performed. Microbiologically documented infections were classified at final evaluation as either eradicated, persistent, or indeterminate if follow-up cultures could not be obtained. Superinfections were defined as presence of a new organism judged to be causing an infectious process during, or at the end, of study drug therapy.
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Table L Minimum inhibitory concentrations (MIC) and fraction inhibitory concentration (FIC) indices of ciprofloxacin and teicoplanin
Bacterial strain
MIC (mg/1) ciprofloxacin teicoplanin
FIC index
0-5 10 10 20 10
0-12 0-25 0-5 0-5 0-25
20 1-25 1-5 10 1O
Methicillin-resistant Staph. aureus S113 MRSA 1 MRSA6 MRSA 23 MRSA 25 MRSA 27
0-5 20 10 10 20 0-5
0-5 05 0-5 0-25 0-5 05
20 10 1-25 10 10 20
Methicillin-sensitive coagulase-negative staphylococci Staph. epidermidis SK360 Staph. epidermidis-B6&3 Staph. epidermidis B9226 Staph. epidermidis B70 Staph. epidermidis B567 Staph. epidermidis B566 Staph. epidermidis B280 Staph. epidermidis B47 Staph. epidermidis B603
40 40 40 10 40 80 80 80 20
025 025 025 025 05 05 025 20 05
1-5 1-5 10 075 10 10 1-5 1-5 075
isolates was similar to that observed for the Staph. aureus isolates. The FIC indices of mixtures of the two drugs were between 0-75 and 1-5 indicating an additive effect. Hence all 20 of the staphylococcal isolates tested were sensitive to both ciprofloxacin and teicoplanin and mixtures of the two drugs were found to be either additive or indifferent. With the 4-quinolones, MICs only provide information on the inhibition of bacterial multiplication. Ciprofloxacin not only inhibits bacterial multiplication but is bactericidal to staphylococci in nutrient broth (Figure 1). Ciprofloxacin displayed a biphasic response against Staph. aureus E3T and Staph. epidermidis SK36O, with an optimum killing concentration of 3 mg/1 for both species (Figure 1). The bactericidal activity of teicoplanin was also investigated against both of these species in nutrient broth. Teicoplanin was also found to be bactericidal to both species over three hours at clinically achievable concentrations (Figure 2). However, teicoplanin did not display a biphasic response: the degree of kill was concentration dependent. The bactericidal activity of mixtures of teicoplanin and ciprofloxacin against these two species was then investigated by observing the effect of increasing teicoplanin concentrations on the bactericidal activity of a static concentration of ciprofloxacin against Staph. aureus E3T and Staph. epidermidis SK360 in nutrient broth.
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Methicillin-sensitive Staph. aureus NCTC 6571 E3T 10B14 10B33 10B57
Interaction of teicoplanin and dprofloxadn
553
1000
I 10 Ciprofloxacin (mg/L)
100
Figure 1. Tbe effect of ciprofloxacin on the survival of Staph. aureus E3T ( # ) and Siaph epulermidis SK36O (O) 'n nutrient broth. Slaph. aureus E3T and Slaph. tpidermidis SKJ60 were exposed to various concentrations of ciprofloxacin in nutrient broth. After 3 h incubation at 37°C, percentage survival was estimated by viable counting on nutrient agar.
When teicoplanin was added to ciprofloxacin at its optimum killing concentration of 3 mg/1 no reduction in the amount of kill occurred as the teicoplanin concentration in the mixture increased (Figure 3). If anything, the bactericidal activity increased as the concentration of teicoplanin in the mixture rose. The effect of increasing concentrations of ciprofloxacin on the bactericidal of a clinically achievable teicoplanin concentration 10 mg/1 was also determined. Teicoplanin (10 mg/1), on its own, was bactericidal and a slight increase in the bactericidal activity of the mixtures occurred as the concentration of 4-quinolone in the mixtures rose (Figure 4). Hence, there does not appear to be a reduction in the bactericidal activity of mixtures of ciprofloxacin and teicoplanin as the amount of kill observed with mixtures of the two drugs was no less than that observed when either drug was used alone. Results of the clinical study Twenty nine febrile, neutropenic patients were treated with teicoplanin and ciprofloxacin in the 12 months up to December 1989. Twenty-eight were evaluated for efficacy; one patient withdrew consent after one day of therapy. Mean patient age was 33 ±12 years and mean duration of therapy with trial antibiotics was 7±3 days. None of the patients in this study suffered from renal impairment. There were 18 (64%) microbiologically documented infections (all bacteraemias), three (11%) clinically documented infections (throat, chest, Hickman line skin entry site) and seven (25%) PUOs. Nineteen primary pathogens were isolated from the 18 microbiologically documented infective episodes. 15 (79%) were Gram-positive organisms of which ten (53%) were Staph. epidermidis (Table II).
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•I
554
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100
Figure 2. The effect of teicoplanin on the survival of Staph. aureus E3T ( • ) and Slaph epidermidis SK.360 (O) in nutrient broth. Staph. aureus E3T and Slaph. epidermidis SK.360 were exposed to various concentrations of teicoplanin in nutrient broth. After 3 h incubation at 37°C, percentage survival was estimated by viable counting on nutrient agar.
At final clinical evaluation of therapy, 20 (71%) of the 28 febrile episodes had resolved, one (4%) had improved and six (21%) failed to resolve. One patient could not be evaluated clinically because of coexistent cytomegalovirus pneumonia. Three patients (11%) responded with concomitant recovery of their neutrophil count to 1 x 109/!. When the 17 clinically evaluated, microbiologically documented infections were considered separately 13 (76%) clinically resolved, one (6%) improved and three (18%) had failed to resolve. Two failures were in episodes where the primary pathogen was Staph. epidermidis; one of these developed an Aspergillus fumigatus pneumonia which caused deterioration of his clinical state while the other patient required modification of therapy after 96 h because of persistent fever but subsequently responded to a second line antibiotic combination of vancomycin and ceftazidime. For Gram-positive infections, therefore, clinical resolution of fever occurred in 12 (80%) cases with only two cases (13%) failing to respond (Table II). A similar response rate (80%) was seen for staphylococcal infections. Microbiological evaluation of documented infections revealed that infecting pathogens were eradicated in 11 (61%) episodes while only two (11%) persisted. Follow up cultures were not obtained in five cases (28%) making outcome indeterminate. The persisting organism in one case was Candida tropicalis and in the other Enterobacter cloacae. No Gram-positive organisms were documented to have persisted following study antibiotic therapy (Table II).
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I 10 Tetcoplanln (mg/L)
Interaction of tekoplanin and dprofloxacin
555
100
100
Figure 3, The influence of teicoplanin on the survival of Slaph. aweus E3T ( • ) and Slaph. epidermidis SK.360 (O) treated with a fixed concentration of dprofloxadn. Staph. aweus E3T and Slaph. epidermidis SK.360 were exposed to dprofloxadn (3 mg/1) alone or in the additional presence of various concentrations of teicoplanin, in nutrient broth. After 3 h incubation at 37°C, percentage survival was estimated by viable counting on nutrient agar. 100
01 I Clprofloiocln (mg/l)
10
Figure 4. The influence of dprofloxadn on the survival of Slaph. aureus E3T ( • ) and Slaph. epidermidis SK360 (O) treated with a fixed concentration of teicoplanin. Slaph. aureus E3T and Staph. epidermidis SK36O were exposed to tekoplanin (10 mg/0 alone or in the additional presence of various concentrations of dprofloxadn, in nutrient broth. After 3 h incubation at 37°C, percentage survival was estimated by viable counting on nutrient agar.
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I 10 Teicoplanin (mg/l)
1
14°
19
Total
"One Sir. sanguis infection was clinically unevaluable (see text).
0 0 0 0 1 0 0 0
8 2 1* 1 0 1 1 0 3
2 0 0 0 0 0 0 1
Clinical treatment results failed resolved improved
10 2 2 1 1 1 1 1
No. of cases
Staph. epidermidis Enterococcus sp. Streptococcus sanguis Str. viridans Escherichia coli Pseudomonas spp. Enterobacter cloacae C. tropkalis
Bacterial Strain
13
0
8 1 1 1 1 1 0
eradicated
2
0 0 0 0 0 0 1 1
4
2 1 1 0 0 0 0 0
Microbiological results indeterminate persisted
Table II. Clinical and microbiological outcome for all microbiologically documented infections
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2 &
(A
P
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Discussion The interaction of ciprofloxacin and teicoplanin against staphylococci, including isolates from a clinical trial, was investigated and no antagonism could be found between the two drugs in terms of the FIC indices. In agreement with the results of other investigators (Watt, 1989) the two drugs, in combination, were either additive or indifferent. The mixture of teicoplanin and ciprofloxacin was found to be as effective against MRSA as it was against MSSA. This is particularly significant considering the high levels of ciprofloxacin resistance reported in MRSA (Hawkey, 1989; Schaefler, 1989; Lewin, Allen & Amyes, 1990) as the combination of ciprofloxacin with teicoplanin may serve to prevent the emergence of resistant organisms. Investigation of the bactericidal activity of mixtures of the two drugs again found no evidence to indicate any antagonism of the killing activity against staphylococci. Hence these in-vitro studies could not find any evidence of antagonism occurring between these two classes of drugs suggesting that the combination of ciprofloxacin and teicoplanin should be effective clinically. Our preliminary clinical investigations suggest that ciprofloxacin and teicoplanin in combination are effective in treating staphylococcal infections in neutropenic patients. Our data reveal that, when used empirically, 80% of Gram-positive infections resolved with this regimen and 75% of febrile episodes overall either resolved or improved. This response rate corresponds favourably with that of 80% obtained when teicoplanin was used in a triple regimen with amikacin and ceftazidime to treat febrile neutropenic patients after chemotherapy (Del Favero et al., 1987). In our study only two Gram-positive infections, both caused by Staph. epidermidis, failed to resolve with teicoplanin and ciprofloxacin, although in only one case was clinical failure possibly due to persistence of staphylococcal bacteraemia. Previous studies using antibiotic regimens containing teicoplanin to treat staphylococcal infection have recorded failure rates of 8% in immunocompetent hosts (Lewis, Garaud & Parenti, 1988) and 10% for neutropenic hosts (Menichetti et al., 1988); failure of clinical response in these studies correlates poorly with in-vitro sensitivity of the pathogens to teicoplanin and, in many cases, is associated with eradication of the isolated organism. No severe antibiotic-associated adverse reactions were recorded in our study. In
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There were two documented superinfections in patients while receiving teicoplanin and ciprofloxacin. One patient developed aspergillus pneumonia and another a Candida spp. pneumonia. Two further patients had recrudescences of fever while receiving study antibiotics, which only resolved when amphotericin B was administered intravenously although no superinfecting pathogens were isolated. A further patient grew Staph. epidermidis from Hickman line blood 12 h after stopping teicoplanin suggesting persisting line colonization with this organism despite therapy. However, in no case were Hickman lines removed because of infection. AH infections that were thought to be line-associated were treated with antibiotics only. Adverse reactions, possibly related to antibiotic therapy, were noted in seven (24%) cases. Five of these were mild (less than twice normal) rises in liver aspartate and alanine transaminases. One patient developed mild hyperbilirubinaemia and one a rise in serum liver transaminases up to five times the upper limit of normal. In no case did toxicity lead to worsening of the patient's condition or necessitate withdrawal of study antibiotics.
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particular, no nephrotoxicity was observed. Mild, transient derangement of liver transaminase levels, as seen in 24% of our patient group, have previously been recorded following administration of teicoplanin (Lewis et at., 1988) without clinical sequelae. We conclude that teicoplanin with ciprofloxacin is an effective antibacterial combination against staphylococci both in vitro and in neutropenic patients. This provides a useful, nontoxic regimen for the empirical treatment of fever in the immunocompromised host. Acknowledgements
References Buniva, G., Del Favcro, A., Bernareggi, A., Patoia, L. & Palumbo, R. (1988). Pharmacokinetics of MC-tcicoplanin in healthy volunteers. Journal of Antimicrobial Chemotherapy 21, Suppl. A, 23-8. Del Favero, A., Menichetti, F., Guerciolini, R., Bucaneve, G., Baldelli, F., Aversa, F. et al. (1987). Prospective randomized clinical trial of teicoplanin for empiric combined antibiotic therapy in febrile, granulocytopenic acute leukemia patients. Antimicrobial Agents and Chemotherapy 31, 1126-9. Greenwood, D. (1988). Microbiological properties of teicoplanin. Journal of Antimicrobial Chemotherapy 21, Suppl. A, 1-13. Hawkey, P. M. (1989). Where are we now with ciprofloxacin? Journal of Antimicrobial Chemotherapy 24, 477-80. Kelsey, S. M., Wood, M. E., Shaw, E., Jenkins, G. C. & Newland, A. C. (1990). A comparative study of intravenous ciprofloxacin and benzylpenicillin versus nctilmicin and piperacillin for the empirical treatment of fever in neutropenic patients. Journal of Antimicrobial Chemotherapy 25, 149-57. Klastersky, J. (1986). Concept of empiric therapy with antibiotic combinations. American Journal of Medicine 80, Suppl. 5C, 2-12. Lewin, C. S., Allen, R. A. & Amyes, S. G. B. (1990). Potential mechanisms of resistance to the modern fluorinated 4-quinolones. Journal of Medical Microbiology 31, 153-61. Lewin, C. S. & Amyes, S. G. B. (1989.The bactericidal activity of DR-3355, an optically active isomer of ofloxacin. Journal of Medical Microbiology 30, 227-31. Lewin, C. S., Howard, B. M. A., Ratcliffe, N. T. & Smith J. T. (1989). 4-Quinolones and the SOS response. Journal of Medical Microbiology 29, 139-44. Lewin, C. S. & Smith, J. T. (1989). Interactions of the 4-quinolones with other antibacterials. Journal of Medical Microbiology 29, 221-7. Lewis, P., Garaud, J-J. & Parenti, F. (1988). A multicentre open clinical trial of teicoplanin in infections caused by Gram-positive bacteria. Journal of Antimicrobial Chemotherapy 21, Suppl. A, 61-7. Menichetti, F., Del Favero, A., Bucaneve, G., Aversa, F., Baldelli, F., Felicini, R. et al. (1988). Teicoplanin in empirical combined antibiotic therapy of bacteraemias in bone marrow transplant patients. Journal of Antimicrobial Chemotherapy 21, Suppl. A, 105-11. Schaefler, S. (1989). Methicillin-resistant strains of Staphylococcus aureus resistant to quinolones. Journal of Clinical Microbiology 27, 335-6. Smith, G. M., Leyland, M. J., Farrell, I. D. & Geddes, A. M. (1988). A clinical, microbiological and pharmacokinetic study of ciprofloxacin plus vancomycin as initial therapy of febrile episodes in neutropenic patients. Journal of Antimicrobial Chemotherapy 21, 647-55.
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We should like to thank the Clinical and Biomedical Research Committee of the Scottish Home and Health Department for grant no. K/MRS/50/C1135 and Merrell Dow Pharmaceuticals for their support of this investigation.
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Smith, S. R., Chcesbrough, J., Spearing, R. & Davies, J. M. (1989). Randomized prospective study comparing vancomycin with teicoplanin in the treatment of infections associated with Hickman catheters. Antimicrobial Agents and Chemotherapy 33, 1193-7. Watt, B. (1989). Interaction of teicoplanin with other antimicrobial agents against Gram-positive aerobes. Journal of Antimicrobial Chemotherapy 23, 657-8. Williams, A. H. & Gruneberg, R. N. (1984). Teicoplanin. Journal of Antimicrobial Chemotherapy 14, 441-5. {Received 16 January 1990; revised version accepted 4 June 1990)
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