Antimicrobial Resistance among Acinetobacter species and Evaluation of Risk Factors

Background: Acinetobacter has gained importance as an emerging multi drug resistant nosocomial pathogen among non fermenting aerobic gram negative bacteria, especially in intensive care units. This organism is contributing to increased morbidity and mortality with strong propensity to colonize and disseminate among humans and environmental sources.
Materials and Methods: A retrospective observational study was conducted from February 2013 to December 2013. Various clinical specimens received in microbiology laboratory from inpatients and outpatients were studied including their antimicrobial resistance pattern. A total of 111 Acinetobacter species isolates were included in the study. Associated risk factors were recorded from the clinical data which included demographic characteristics of the patient along with the indoor department, period of stay in ICU and hospital, presence of indwelling devices, antimicrobial therapy, surgical interventions, focal or generalized infections and underlying chronic morbid diseases.
Results: In current study maximum number of Acinetobacter was from urine specimen (57.66%) followed by blood (25.23%). Among inpatients highest percentage of isolates was recovered from general surgical ward (26.88%) followed by intensive care units (24.73%). The number of MDR & XDR isolates recovered was 21(18.92%) & 11(10%) respectively. Imipenem, Meropenem and Doxycycline remained efficacious drugs against Acinetobacter infections with resistance rates of 18.02%, 30.63% and 36.94% respectively. The study revealed focal/generalized infections, indwelling devices, duration of stay in ICU & hospital, mechanical ventilation as significant risk factors in decreasing order for acquisition of MDR and XDR Acinetobacter but according to the statistical analysis only Diabetes mellitus was found to be significant (p value 0.019) whereas all other factors remained insignificant ( p value > 0.05).
Conclusion: Prolonged usage of indwelling devices & medical equipments in critically ill patients along with longer duration of hospitalization can facilitate colonization and infection with Acinetobacter which is otherwise a low virulence pathogen. Strict compliance of disinfection policy and infection control programme with rational use of antibiotics especially carbapenems in Acinetobacter infections shall help in curtailing drug resistant strains from further dissemination.