Anaerobic Bacteraemia Revisited: Species and Susceptibilities

Abstract

Introduction: This retrospective study was performed to evaluate the frequency of anaerobic bacteraemia over a 10-year period, and to provide updated antibiotic susceptibilities for the more clinically relevant anaerobes causing blood stream infection. Materials and Methods: Data were retrieved from the laboratory information system for the period 2003 to 2012. During this time, blood cultures were inoculated in Bactec™ Plus vials (BD, USA) and continuously monitored in the Bactec™ 9000 blood culture system (BD, USA). Anaerobic organisms were identified using commercial identification kits, predominantly API 20 A (bioMérieux, France) supplemented with Vitek ANC cards (bioMérieux, France) and AN-Ident discs (Oxoid, United Kingdom). A representative subset of isolates were retrieved from 2009 to 2011 and antimicrobial susceptibilities to penicillin, amoxicillin-clavulanate, clindamycin, imipenem, moxifloxacin, piperacillin-tazobactam and metronidazole were determined using the Etest method. Results: Anaerobes comprised 4.1% of all positive blood culture with 727 obligate anaerobes recovered over the 10-year period, representing a positivity rate of 0.35%. The only significant change in anaerobe positivity rates occurred between 2003 and 2004, with an increase of 0.2%. The Bacteroides fragilis group (45%) were the predominant anaerobic pathogens, followed by Clostridium species (12%), Propioniobacterium species (11%) and Fusobacterium species (6%). The most active in vitro antibiotics were imipenem, piperacillin-tazobactam, amoxicillin-clavulanate and metronidazole, with susceptibilities of 95.0%, 93.3%, 90.8% and 90.8% respectively. Resistance was high to penicillin, clindamycin and moxifloxacin. However, there were apparent differences for antibiotic susceptibilities between species. Conclusion: This study indicates that the anaerobes comprise a small but constant proportion of bloodstream isolates. Antibiotic resistance was high to some antibiotics, but metronidazole, the beta-lactam/beta-lactamase inhibitors and carbapenems retained good in vitro activity. Key words: Antibiotic resistance, Bacteroides

Antimicrobial Susceptibility Profile of Rare Anaerobic Bacteria

“…Often piperacillin/tazobactam is reported as 100% susceptible. Our piperacillin/tazobactam resistance rate of 2/12 isolates is similar to the one reported by Ng, Lily et al ( 2015) [30].…”

“…presented with resistance to penicillin, moxifloxacin, and clindamycin. These findings can be supported by other surveillance studies [14,15,30]. Often piperacillin/tazobactam is reported as 100% susceptible.…”

Anaerobic Gram-Negative Bacteria: Role as a Reservoir of Antibiotic Resistance

“…The literature survey showed an even higher resistance rate in Prevotella, i.e., up to 40% in Europe, 50% in both US and Asia, and highest in Kuwait, around 89% [15]. In Fusobacterium spp., the resistance rates of Asian countries such as Taiwan (31%) [24] and Singapore (44%) [25] are similar to ours; however, a ≤15% resistance has been reported from the rest of the world. Clindamycin, which was earlier believed to be a drug of choice for infections above the diaphragm, now calls for attention, since Prevotella and Fusobacterium are usual isolates of orodental and other above-diaphragm infections.…”

Pathogenesis diagnosis of a pediatric patient suffering from multi-organ abscesses

“…The mNGS result of plasma verified bloodstream infection. In fact, there were literature reports for anaerobic bacteraemia ( Bacteroides fragilis was the predominant anaerobic pathogen, followed by Clostridium species and Propionibacterium species), liver and kidney abscesses caused by anaerobe ( Clostridium clostridioforme ), and renal abscess caused by anaerobe ( Peptostreptococcus asaccharolyticus ) [ 2 – 4 ]. This patient had no special past history, and did not suffer from oral and gastrointestinal infections.…”