Detection of Biofilm Formation, Motility and Underlying Conditions and Their Association with the Antibiotic Resistance Pattern in Acinetobacter Species Isolated from Different Clinical Samples in a Tertiary Care Centre in North Eastern Part of Bihar

Abstract

Introduction: Acinetobacter baumannii complex (ABC) has become a vexing problem in clinical medicine causing different types of health care associated infections in association with use of contact lenses after eye surgery.

Aims and Objectives: The primary aim of the study was to try to assess the association of biofilm formation, motility and underlying clinical conditions to the antibiotic resistance pattern in Acinetobacter species isolated from different clinical samples in a Tertiary Care Centre in north eastern part of Bihar.

Materials and Methods: Clinical samples were collected from patients with symptomatic clinical infections at least 48h after hospital after collection of essential demographic data like gender, age, underlying diseases, risk factors and duration of hospital stay. Identification of Acinetobacter baumannii was done using standard biochemical methods, Vitek 2 AES and use of primers. Motility testing was done using two methods, viz: (1) Crystal Violet, and (2) TTC dyes. Biofilm detection was done using measurement of absorbance of bacteria after pre-treatment using standard dyes and placing & drying them on 96-well polystyrene microtiter plates. Antibiotic susceptibility was detected, recorded and analyzed using the Vitek 2 AES.

Results: 25% of the strains showed surface motility by TTC method. Twitching motility was seen in 5% of the isolates by CV method and 16.6% by TTC method whereas 87.5% strains were non-motile by CV method and 83.3% strains were non-motile by the TTC method. 62.5% resistance to imipenem followed by 48.5% to ceftazidime, 43.9% to trimethoprim / sulfamethoxazole and 42.8% to meropenem. 54.2% strains that were colistin resistant were biofilm producers as compared to 45.7% strains that were non-biofilm producing.

Conclusion: It can be concluded that the Acinetobacter baumannii isolates showed a wide spectrum of multidrug resistance, leaving little treatment options using a combination of colistin and tigecycline remains crucial for treating multidrug-resistant Acinetobacter baumannii until new therapeutic options become available.

Keywords: Biofilm, motility, Antibiotic resistance, Acinetobacter baumannii complex