CLSI based antibiogram profile and the detection of MDR and XDR strains of Acinetobacter baumannii isolated from urine samples

Background: Acinetobacter baumannii is an emerging nosocomial pathogen causing serious complications due to the propensity of its multi-drug resistant property. Due to the indiscriminate and wide-spread use of antibiotics, A. baumannii strains emerge as MDR-Ab, XDR-Ab and in recent years pan-DR-Ab strains. Routine therapy incorporates the application of fewer antibiotics and antibiotic surveillance data is not monitored frequently. This study is thus an attempt to screen for the frequency of antibiotic resistance profile against different classes of antibiotics as per CLSI guidelines. Methods: Phenotypically and genotypically characterized 73 A. baumannii strains were utilized for the antibiogram profile using Group A, B, and U antibiotics as per CLSI recommendations using standard Kirby Bauer disc diffusion method. Interpretations of susceptible, intermediate and resistance were recorded by measuring zone diameter criteria. Results: Group A antibiogram profile showed highest non-susceptibility (n=73) (100%) to ampicillin-sulbactam, ceftazidime and imipenem followed by 82.19%, 79.45%, 67.12%, 56.16% and 49.31% non-susceptible isolates against ciprofloxacin, gentamicin, meropenem, tobramycin, and levofloxacin respectively. Group B antibiogram profile showed 100% non-susceptibility piperacillin-tazobactam and to amikacin, 91.78% (n=67) resistance against ceftriaxone. Among the cyclines, 19.71% and 6.84% of isolates were resistant to doxycycline and minocycline respectively. Under Group U, 76.71% showed resistance against tetracycline. The frequency of MDR (71.23%) and XDR (39.72%) A. baumannii isolates were detected. Conclusion: Periodical antibiotic surveillance is essential to curb the menace of the emergence of MDR and XDR A. baumannii in the hospital environment thus improving the patient care by the administration of alternate drug of choice or by combination therapy.