Antimicrobial resistance and prevalence of resistance genes in intestinal Bacteroidales strains

Abstract

OBJECTIVE:This study examined the antimicrobial resistance profile and the prevalence of resistance genes in Bacteroides spp. and Parabacteroides distasonis strains isolated from children's intestinal microbiota.METHODS:The susceptibility of these bacteria to 10 antimicrobials was determined using an agar dilution method. β-lactamase activity was assessed by hydrolysis of the chromogenic cephalosporin of 114 Bacteriodales strains isolated from the fecal samples of 39 children, and the presence of resistance genes was tested using a PCR assay.RESULTS:All strains were susceptible to imipenem and metronidazole. The following resistance rates were observed: amoxicillin (93%), amoxicillin/clavulanic acid (47.3%), ampicillin (96.4%), cephalexin (99%), cefoxitin (23%), penicillin (99%), clindamycin (34.2%) and tetracycline (53.5%). β-lactamase production was verified in 92% of the evaluated strains. The presence of the cfiA, cepA, ermF, tetQ and nim genes was observed in 62.3%, 76.3%, 27%, 79.8% and 7.8% of the strains, respectively.CONCLUSIONS:Our results indicate an increase in the resistance to several antibiotics in intestinal Bacteroides spp. and Parabacteroides distasonis and demonstrate that these microorganisms harbor antimicrobial resistance genes that may be transferred to other susceptible intestinal strains.

Detection of integron-associated gene cassettes and other antimicrobial resistance genes in enterotoxigenic Bacteroides fragilis

“…Similar to previous reports [37], tetracycline resistance in ETBF strains is most likely associated with the presence of tet(Q). The nimE gene was positively associated with metronidazole resistance in ETBF as reported previously [24,38].…”

“…Two nim-negative strains expressing high levels of resistance to metronidazole have been detected in this study. As reported previously in Bacteroides there many other mechanism for metronidazole resistance [37]. Similarly, the b-lactam resistance was not demonstrated by all bla TEM bearing strains suggesting the presence of other resistance mechanisms.…”

First Hungarian case of an infection caused by multidrug-resistant Bacteroides fragilis strain

“…The susceptibility of isolates of the B. fragilis group has been demonstrated to vary for individual species, by geographic location and medical institutions [3][4][5][6][7][8][9][10][11][12][13][14]. In vitro antimicrobial susceptibility testing results have been shown to be relevant to determining patient outcome, even in the presence of mixed infections.…”

“…The most frequently used antibiotics against this group of microorganisms are clindamycin, cephamycins, betalactam/beta-lactamase inhibitors, fourth-generation fluorquinolones, nitroimidazoles and carbapenems. Over the last years, increasing resistance of these bacteria to several antibiotics has been reported from different countries [3][4][5][6][7][8][9][10][11][12][13][14]. In Hungary, multi-drug resistance has not been reported among Bacteroides spp.…”

Emerging Metronidazole Resistance in Anaerobes and Mapping Their Susceptibility Behaviour

“…However, in the past few years, metronidazole resistance among obligate anaerobes is a matter of concern as intermediate or highlevel resistance to metronidazole have been reported (Alauzet et al, 2010). 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).…”