In vitro susceptibility of the Bacteroides fragilis group in community hospitals

File, Thomas M.; Thomson, Richard B.; Tan, James S.; Salstrom, Sara‐Jane; Jacobs, George A.; Johnson, Lynette; Tan, Lulu

doi:10.1016/0732-8893(86)90035-0

Cited by 10 publications

(8 citation statements)

References 8 publications

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“…My results are in agreement with most of the reports. However, the ceftizoxime MIC50 and MIC90 of c4 and 32 ,g/ml, respectively, for the B. fragilis group were considerably lower than the 32 and >128 ,ug/ml reported by File et al (16) but in agreement with the 4 and 16 ,ug/ml reported by Thomsberry (34) and the 2 and 16 ,ug/ml of Aldridge et al…”

Section: Fekete Et Al (15) Demonstrated a Marked Reduction Insupporting

confidence: 68%

“…The percent susceptible at a <16-tLg/ml breakpoint for the individual species of the bile-resistant group from this study and the reports of Aldridge et al (1) (32) or even from different hospitals in the same area (5,16). It is noteworthy that most of the resistant strains in the report of File et al (16) came from smaller community hospitals and not the large institution in their study.…”

Section: Fekete Et Al (15) Demonstrated a Marked Reduction Inmentioning

confidence: 38%

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National Committee for Clinical Laboratory Standards agar dilution susceptibility testing of anaerobic gram-negative bacteria

Brown

1988

Antimicrob Agents Chemother

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One hundred nine recent clinical isolates of anaerobic gram-negative bacteria were tested in triplicate by the National Committee for Clinical Laboratory Standards agar dilution procedure for their susceptibility to 32 antimicrobial agents. All isolates were inhibited by imipenem, but there were significant numbers of strains resistant to other beta-lactam drugs, and therefore the in vitro response to these antimicrobial agents cannot be predicted. This was particularly true for the bile-resistant or Bacteroides fragilis group. P-Lactamase production was detected in 82% of the bacteroides with the nitrocefin test. Clavulanic acid combined with amoxicihlin and ticarcillin and sulbactam combined with ampicillin resulted in synergistic activity against all I8-lactamase-positive organisms. Ceftizoxime was the most active of the cephalosporins. Two percent of the isolates were resistant to chloramphenicol and metronidazole. Clindamycin resistance was detected in 38% of the B. fragilis group, which is a marked increase from the 4% detected 10 years ago at this institution.Susceptibility testing of anaerobic bacteria has been accepted and recommended during the last few years (4,27,31). This change is attributable to the development of a standardized reference method (26) and convenient-to-use broth microdilution systems. Another major factor has been the recognition during the last decade of resistance among anaerobic bacteria. Prior to 1980, a few drugs were believed to be effective against almost all anaerobic bacteria. However, resistance to most of the traditionally used antimicrobial agents and most of the newer beta-lactam antibiotics has been increasingly reported (27,31,37). Furthermore, Cuchural and Tally (10) have found that resistance varies with geographical area and even from time to time within the same institution.The purpose of this study was to examine a large variety of antimicrobial agents by the reference agar dilution method.The bacteria tested were recent clinical isolates of the most commonly occurring anaerobic gram-negative bacteria. Nine years ago at this institution, the first clinical isolates of the Bacteroides fragilis group resistant to clindamycin were detected by the agar dilution technique (8). I was interested in comparing the results for current clinical isolates with results from the previous study and in examining newer antimicrobial agents.MATERIALS AND METHODS Microorganisms. One hundred nine recent clinical isolates of anaerobic gram-negative bacteria were isolated from specimens submitted to the clinical microbiology laboratory at Hutzel Hospital in the Detroit Medical Center. Strains were tested from August 1986 to March 1987. Species identification was performed by standard methods, including gas-liquid chromatography (17), bile resistance, lipase production, and the API 20A test system (Analytab Products, Inc., Plainview, N.Y.). Seventy of the strains were bileresistant species of Bacteroides and were identified as B. fragilis (n = 24), B. distasonis (n = 14), B. vulgatus (...

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Section: Fekete Et Al (15) Demonstrated a Marked Reduction Insupporting

confidence: 68%

Section: Fekete Et Al (15) Demonstrated a Marked Reduction Inmentioning

confidence: 38%

National Committee for Clinical Laboratory Standards agar dilution susceptibility testing of anaerobic gram-negative bacteria

Brown

1988

Antimicrob Agents Chemother

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“…They have generally lower MICs against members of the family Enterobacteraceae than does cefoxitin (4), and cefmetazole has improved activity against S. aureus (15). Although cefotetan and cefmetazole are as effective as cefoxitin against B. fragilis, they are less active against the other members of the B. fragilis group (1,(12)(13)(14)16).…”

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

“…B. fragilis group organisms produce a potent cephalosporinase, and their susceptibilities to expanded-and broad-spectrum cephalosporins are not uniform (1). B. fragilis is the most susceptible, while Bacteroides thetaiotaomicron and other B. fragilis group members are more resistant (1,12,14). The purpose of this study was to evaluate several expanded-spectrum cephalosporins advocated as single-agent therapy for the prophylaxis and management of polymicrobial infections.…”

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confidence: 99%

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Use of cephalosporins for prophylaxis and therapy of polymicrobial infection in mice

Brook

1993

Antimicrob Agents Chemother

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Cefoxitin, cefotetan, and cefmetazole were compared in 10-day therapy of intra-abdominal and subcutaneous infections caused by three organisms: Bacteroidesfragilis and Bacteroides thetaiotaomicron combined with either Escherichia colt or Staphylococcus aureus. Intra-abdominal infection was caused by B. fragilis plus B.thetaiotaomicron plus E. coil. Therapy was initiated immediately before inoculation or was delayed for 8 h. Mortality was 14 of30 (47%) for saline-treated mice, and all survivors developed abscesses. Immediate therapy reduced mortality and the percentage of mice with abscesses (in survivors), respectively, to 17 and 20%o with cefoxitin, 0 and 13% with cefotetan, and 0 and 17% with cefmetazole, and the numbers of all bacteria were reduced by all the cephalosporins. Delayed therapy reduced mortality and abscess formation, respectively, to 20 and 8% of mice with cefoxitin, 10 and 93% with cefotetan, and 7 and 96% with cefmetazole. B. thetaiotaomicron survived in all abscesses treated with cefotetan and cefmetazole. Subcutaneous abscesses were caused by each organism alone or in combinations of one aerobe (S. aureus or E. coli) and one or two Bactetoides species. Early therapy reduced the numbers of all bacteria independent of their in vitro susceptibility. All agents reduced the number of each Bacteroides species with either E. coli or S. aureus.However, when therapy was delayed, cefotetan and cefmetazole were less effective than cefoxitin against B. thetaiotaomicron. Cefotetan was the most active agent against E. coli, and cefmetazole was the most effective against S. aureus. These data illustrate the efficacy of all tested cephalosporins in the prophylaxis of polymicrobial infections.Bacteroides fragilis group organisms mixed with Escherichia coli are frequently isolated from intra-abdominal (i.a.) infections that originate from the gut flora (5, 15). These organisms mixed with Staphylococcus aureus are often recovered from skin and soft tissue infections around rectalvulvovaginal and oral areas (8). The B. fragilis group consists of several subspecies that were elevated to full species level (11).The rates of recovery of the different species of the B.fragilis group differ for various infection sites. The distribution ofB. fragilis group species can affect the management of these infections because of the different antimicrobial susceptibilities of the various group members. B. fragilis group organisms produce a potent cephalosporinase, and their susceptibilities to expanded-and broad-spectrum cephalosporins are not uniform (1). B. fragilis is the most susceptible, while Bacteroides thetaiotaomicron and other B. fragilis group members are more resistant (1,12,14). The purpose of this study was to evaluate several expanded-spectrum cephalosporins advocated as single-agent therapy for the prophylaxis and management of polymicrobial infections. Their abilities to prevent and treat mixed infections caused by two members of the B. fragilis group and either E. coli or S. aureus were tested in i.a. and su...

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Belgian collaborative study of the in-vitro susceptibility of the Bacteroides fragilis group

Glupczynski

1988

Eur J Epidemiol

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The antimicrobial susceptibility of clinical isolates of the Bacteroides fragiIis group .obtained from nine large Belgian university and community hospitals was studied. Of the ,~-lactam anti,biotics tested, none were active against 100% of the isolates. Piperacillin was active against 93% of the strains at a breakpoint of 64 l~g/ml. The percentage of isolates inhibited at 16 l~g/ml (and 32 v.g/ml) for the 7-alpha-methoxy antibiotics was: cefoxitin 84 [94]; latamoxef 87 [93]; and cefotetan 64 [79]. B. fragilis tended to be more susceptible to all ~t-lactams than the .other members of the group.Among the non ~-lactam anti~biotics, the resistance rate for minocycline, doxycycline, clindamycin and erythromycin (at a breakpoint of 4 l~g/ml) were 1%, 4%, 14% and 34%, respectively. Like the i~-lactams, clindamycin was less active against non B. fragilis species of the group.Chloramphenicol, metronidazole and tinidazole were still active against 100% of the isolates at their breakpoint values (8 lxg/ml).

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In vitro susceptibility of the Bacteroides fragilis group in community hospitals

Cited by 10 publications

References 8 publications

National Committee for Clinical Laboratory Standards agar dilution susceptibility testing of anaerobic gram-negative bacteria

National Committee for Clinical Laboratory Standards agar dilution susceptibility testing of anaerobic gram-negative bacteria

Use of cephalosporins for prophylaxis and therapy of polymicrobial infection in mice

Belgian collaborative study of the in-vitro susceptibility of the Bacteroides fragilis group

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