Antimicrobial susceptibility of Bacteroides fragilis group isolates in Europe: 20 years of experience

Abstract

The susceptibilities of 824 Bacteroides fragilis group isolates against nine antibiotics were evaluated in a Europe-wide study involving 13 countries. Species determination, by different methods, was carried out on all but one isolate. Resistance rates were evaluated according to species and geographical areas via CLSI and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints. The present data were compared with those obtained 10 and 20 years ago at a European level. High-level resistance (MIC ≥ 64 mg/L) to ampicillin was observed in 44.5% of the strains, which is a significant increase relative to 20 years ago (16%). Piperacillin/tazobactam was more active than amoxicillin/clavulanic acid (3.1% and 10.4% resistance, respectively), again with a resistance increase relative to earlier studies. Dramatic increases in resistance were observed for cefoxitin, clindamycin and moxifloxacin, with rates of 17.2%, 32.4% and 13.6%, respectively. The lowest resistances were found for imipenem, metronidazole and tigecycline (1.2%, <1% and 1.7%). Nonsusceptible strains to imipenem and metronidazole were more resistant to other anti-anaerobic drugs. Differences were detected between geographical areas, with higher resistance rates for moxifloxacin in Scandinavian countries (21.4%) than in Mediterranean countries (5.4%), whereas, for clindamycin, the resistance rates were higher in Mediterranean (41.8%) and lower in Scandinavian countries (22.5%). Piperacillin/tazobactam resistance was also higher in Scandinavian countries.

The First Metronidazole-Resistant Bacteroides Species Isolated at Marmara University Hospital: Bacteroides thetaiotaomicron

“…Farklı ülkelerden bildirilen metronidazole dirençli Bacteroides türlerinin oranı %1'in altındadır 3,5 . Ülkemizde sınırlı sayıda yapılmış çalışma bulunmaktadır.…”

“…Direnç genlerinin saptanması için, bakteri DNA'sı izole edilmiş, NIM3-F (5'ATG TTC AGA GAA ATG CGG CGT AAG CG-3') ve NIM5-R (5'-GCT TCC TTG CCT GTC ATG TGC TC-3') primerleri kullanılarak PCR ile nim geni amplifiye edilmiştir Çalışılan kökenin metronidazol MİK değeri 16 mg/L'dir. Metronidazol "MİK 16 mg/L" değeri CLSI kriterlerine göre ara değerde (intermediate), EUCAST kriterlerine göre ise dirençli (> 4 mg/L) grubunda yer almaktadır 5,6 . Kökenin, diğer antibiyotiklerden ampisilin ve klindamisine dirençli, ancak ampisilin-sulbaktam ve karbapenemlere duyarlı olduğu gösterilmiştir.…”

“…Bu bakteriler karbapenemler, beta-laktam/beta-laktamaz inhibitörleri ve nitroimidazol gibi sınırlı sayıda antibiyotiklere duyarlıdırlar 2 . Ancak son zamanlarda bazı ülkelerde nadiren de olsa nitroimidazollere dirençli kökenler rapor edilmiştir [2][3][4][5] .…”

Emerging Metronidazole Resistance in Anaerobes and Mapping Their Susceptibility Behaviour

“…These species can also be resistant to a number of other antimicrobial agents such as beta-lactam agents (imipenem and cefoxitin), tetracycline and clindamycin (Boente et al, 2010;Nakano et al, 2011). Metronidazole resistance has been reported in Europe (Nagy et al, 2011;Hartmeyer et al, 2012), United states of America (USA) (Schapiro et al, 2004) and Africa (Buta et al, 2010).…”

“…5-nitroimidazole resistance genes, nimA to E, have been identified to confer reduced susceptibility to 5-nitroimidazole antibiotics on species of the B. fragilis group (Hartmeyer et al, 2012). The nim genes encode a 5-nitroimidazole reductase (Nagy et al, 2011).…”