Antibiotic sensitivity of theBacteroides fragilis group in Europe

Abstract

Rates of resistance to 12 antibiotics were determined for 1,289 isolates of Bacteroides fragilis group submitted in 1988-1989 by 22 laboratories in 15 European countries. There was no resistance to metronidazole (breakpoint 8 mg/l) and only one isolate was resistant to chloramphenicol (breakpoint 8 mg/l). Resistance was uncommon for imipenem (0.3% at greater than 4 mg/l), amoxicillin/clavulanate (1% at greater than 8 mg/l), cefoxitin (3% at greater than 32 mg/l), mezlocillin (6% at greater than 64 mg/l) and clindamycin (9% at greater than 4 mg/l). Resistance was the rule for ampicillin (93% at greater than 4 mg/l), ciprofloxacin (56% at greater than 4 mg/l) and tetracycline (64% at greater than 4 mg/l). Bacteroides fragilis, the commonest species, was generally the most sensitive: resistance of this organism was uncommon for cefotetan (4% at greater than 32 mg/l) and ceftazidime (12% at greater than 32 mg/l) to which the other species were more often resistant. There were small but significant differences between laboratories and countries for many of the antibiotics. Regionally the most striking differences were for clindamycin where resistance in Bacteroides fragilis was most common in the South and for tetracycline where resistance in Bacteroides fragilis, Bacteroides thetaiotaomicron and Bacteroides uniformis was least common in the North.

Antimicrobial resistance in human oral and intestinal anaerobic microfloras

“…In previous studies, B. ovatus and then B. fragilis were the most frequently isolated anaerobic resistant strains from intestinal microfloras (1,12). The antimicrobial susceptibility of the B. fragilis group in the present study correlates well with those found in recent investigations in Canada and Europe (12,16).…”

Susceptibility patterns and characterization of beta-lactamases in clinical isolates ofBacteroids fragilis

“…Since therapy for anaerobic infection is often required before the results of susceptibility tests are available and regional differences in resistance patterns have been well documented (2,3,4,20,21), the results of periodic susceptibility studies are useful as a guide in the empiric choice of agents for a correct treatment. This study confirms the reports of other investigators (20,21) that the following drugs are active against the majority of Bacteroides fragilis strains: metronidazole, imipenem and the combination of a betalactam drug and a beta-lactamase inhibitor such as amoxicillin/clavulanate.…”

“…Among anaerobes pathogenic for humans, Bacteroides fragilis is the member most commonly encountered clinically (1), In recent years the literature has reported an increasing resistance of Bacteroidesfragilis to antimicrobial agents as well as differences in the rates of resistance among strains isolated in different geographical areas (2)(3)(4). Therefore, periodic surveillance using simple and reliable methods is essential for the knowledge of resistance patterns in any specific country.…”

The value of MALDI-TOF MS for the identification of clinically relevant anaerobic bacteria in routine laboratories

“…From resistance surveillance it is known that species determination may be extremely important for routine laboratories in the case of Bacteroides isolates, as significant differences in resistance rates to antibiotics can be observed among the different species (Snydman et al, 2007;Phillips et al, 1992;Hedberg et al, 2003;Nagy et al, 2011b). On the other hand, only B. fragilis isolates belonging to division II can harbour the cfiA gene, responsible for carbapenem resistance.…”