Acinetobacter baumannii Infections and Antibiotic Resistance in Hospitalized Patients in an Education and Research Hospital: A Six-Year Analysis

Abstract

Introduction: Acinetobacter baumanii causes difficulties in the treatment of nosocomial infections due to increasing resistance worldwide. With an increase in resistant infections, the use of colistin has come to the fore. We aimed to investigate the antimicrobial resistance profile of A. baumanii strains isolated from clinical specimens as hospital-acquired colonizations and infection agents and to evaluate the clinical and microbiologic responses and adverse effects of antibiotic regimens used in patients who were isolated because of having infectious agents. Materials and Methods: A retrospective descriptive study of 326 adult patients with nosocomial A. baumannii colonizations and infections was conducted between January 2012 and December 2017 in Niğde Education and Research Hospital. In addition, a total of 212 adult patients who received at least 72 hours of antimicrobial therapy were evaluated. Standard and automated methods were used to identify isolated strains and antibiotic susceptibility. The antimicrobial susceptibility profile change over the 6-year period was evaluated. Adverse effects, and clinical and microbiologic response were evaluated in patients receiving antimicrobial therapy. Analysis of the variables was performed using SPSS 22.0 (IBM Corporation, Armonk, New York, United States). Results: When antimicrobial resistance rates were examined, it was seen that imipenem (99.7%), ampicillin sulbactam (81.6%), cefoperazone sulbactam (60.3%), netilmicin (89.4%), tobramycin (88.4%), gentamicin (83.1%), amikacin (91.6%) and tigecycline (33.7%) had resistance rates; colistin resistance was not detected in the isolates. Resistance rate to other antibiotic groups was 100%. The resistance rates of ampicillin sulbactam, cefoperazone sulbactam, gentamicin, amikacin, and tigecycline were found to be statistically significant (p< 0.05). There were no significant differences in terms of nephrotoxicity, and clinical and microbiologic response among patients in whom colistin was used in combination with carbapenem, ampicillin/sulbactam, cefoperazone/sulbactam, and tigecycline (p> 0.05). Conclusion: In accordance with the global data, antimicrobial resistance rate in A. baumanii isolates was found to be high in our study. Treatment regimens in which colistin is used with other antimicrobial agents have no superiority in terms of efficacy and adverse effects. There is a clear need for new and effective antimicrobial agents in the treatment of resistant A. baumanii infections.