Antimicrobial Susceptibility of Clinically Relevant Gram-Positive Anaerobic Cocci Collected over a Three-Year Period in the Netherlands

Abstract

The susceptibility of 14 species of 115 Gram-positive anaerobic cocci (GPAC) was determined for 14 antibiotics. To assure correct identification, strains were genotypically identified by fluorescence in situ hybridization and sequencing. Susceptibility differences (MIC 50 and MIC 90 ) for penicillin G, clindamycin, tigecycline, levofloxacin, amoxicillin-clavulanic acid, cefoxitin, ertapenem, meropenem, metronidazole, and doxycycline were found for the three clinically most relevant GPAC species: Finegoldia magna, Parvimonas micra, and Peptoniphilus harei.

Antibiotic susceptibility profiles of anaerobic pathogens in The Netherlands

“…Remarkably, in this study P. harei showed the highest resistance for clindamycin (Table 3, 21%) which is in contrast to previous studies in which no resistance to clindamycin was found [5,8]. P. harei clindamycin resistance increased from about 10% in 2011 and 2012 to 40% in 2013.…”

“…The proportions of the other prevalent species within this group are similar. The proportion of the most prevalent GPAC strains F. magna, P. micra and P. harei are comparable with previous data [5,8]. It is difficult to compare the proportion of P. harei with other studies, because it is difficult to identify this species with phenotypic methods [9].…”

“…P. harei clindamycin resistance increased from about 10% in 2011 and 2012 to 40% in 2013. In previous studies [5,15] no clindamycin resistant P. micra strains were encountered. The search in our database yielded 3 isolates, out of 69, of clindamycin resistant P. micra strains.…”

“…The antimicrobial resistance among non-Bacteroides fragilis species has been shown to be greater than among B. fragilis [4]. Also among the Grampositive anaerobic cocci (GPAC) the antibiotic resistance differs between Finegoldia magna, Parvimonas micra and Peptoniphilus harei [5]. The identification of anaerobic strains was, until recently, time consuming and not always unambiguous.…”

Gram-positive anaerobic cocci – commensals and opportunistic pathogens

“…However, the type strain of P. asaccharolyticus (ATCC 14963) is not representative of the species and a low DNA-DNA homology between clinical isolates and the type strain was described. Thus, a number of type strains were reidentified using 16S rRNA gene sequencing and the closest relative for the strains was P. harei (Veloo et al, 2011a). Peptoniphilus harei and P. asaccharolyticus share the same biochemical features and it was concluded that the isolates of P. asaccharolyticus were misidentified.…”