title: High rate of non-susceptibility to metronidazole and clindamycin in anaerobic isolates: Data from a clinical laboratory from Karachi, Pakistan.
abstract: Due to increasing resistance amongst anaerobic pathogens periodic surveillance of resistance has been recommended in regional/local settings. Anaerobic antimicrobial susceptibility testing is not routinely performed in many laboratories in Pakistan, hence absence of local data may lead to inappropriate empirical therapy in serious cases. 121 clinically significant anaerobic strains (26/121; 21% bacteremic isolates) were isolated and saved from 2010 to 2011. Susceptibility testing against metronidazole, clindamycin, co-amoxiclav, meropenem, piperacillin/tazobactam, linezolid and gatifloxacin was performed by determining minimum inhibitory concentrations (MICs). A high proportion of non-susceptible strains to metronidazole (10% of 121 isolates) and clindamycin (12% of 121 isolates) was seen, most noticeable in Bacteroides fragilis. Three Bacteroides species strains were non-susceptible to both metronidazole and clindamycin. One strain of Clostridium species was fully resistant to metronidazole and had intermediate resistance to clindamycin. No resistance to any of the other tested antibiotics was seen. Resistance to metronidazole was higher in bacteremic vs. non bacteremic isolates (p = value 0.07). In our setting where there is a high usage of empirical metronidazole and clindamycin for the treatment of serious anaerobic infections clinicians should be aware of increased resistance to these agents. Periodic surveillance of resistance to anti-anaerobic drugs especially metronidazole and clindamycin should be performed to generate antibiogram and guide appropriate empiric therapy.
authors: Department of Pathology Microbiology, Aga Khan University, Karachi, Pakistan.
authors: Sadia Omer
authors: SO
authors: Sheikh
authors: Department of Pathology Microbiology, Aga Khan University, Karachi, Pakistan. Electronic address: kausar.jabeen@aku.edu.
authors: Kauser
authors: K
authors: Jabeen
authors: Department of Pathology Microbiology, Aga Khan University, Karachi, Pakistan.
authors: Saba
authors: S
authors: Qaiser
authors: Department of Pathology Microbiology, Aga Khan University, Karachi, Pakistan.
authors: Syed Tanwir
authors: ST
authors: Ahsan
authors: Department of Pathology Microbiology, Aga Khan University, Karachi, Pakistan.
authors: Erum
authors: E
authors: Khan
authors: Department of Pathology Microbiology, Aga Khan University, Karachi, Pakistan.
authors: Afia
authors: A
authors: Zafar
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001421:Bacteria, Anaerobic / Q000145:classification / Q000187:drug effects* / Q000302:isolation & purification; D001424:Bacterial Infections / Q000453:epidemiology* / Q000382:microbiology*; D002648:Child; D002675:Child, Preschool; D002981:Clindamycin / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D008297:Male; D008795:Metronidazole / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D010154:Pakistan / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D008795:Metronidazole; D002981:Clindamycin
keywords: Anaerobe; Anaerobic infections; Antimicrobial resistance; Pakistan; Susceptibility testing