Biofilm Producing Multidrug Resistant Acinetobacter baumannii: An Emerging Challenge

Aim: To study the quantitative method for biofilm formation and examine the correlation between biofilm formation and antibiotic resistance among the clinical isolates of Acinetobacter baumannii. Materials and Methods: A total of 72 A. baumannii isolates from different clinical specimens were processed and confirmed by conventional microbiological methods. Antimicrobial susceptibility testing was performed by Kirby Bauer disc diffusion method using six antibiotics. Biofilm formation was studied by microtitre plate assay. Results: Forty five (62.5%) of 72 isolates produced biofilm. Resistance to ampicillin-sulbactam was least. 36.1% isolates were resistant to imipenem, 66.6% to ceftazidime, 72.2% to ciprofloxacin, 80.5% to amikacin and 84.7% to piperacillin. Biofilm formers showed greater resistance to ampicillinsulbactam, amikacin, ciprofloxacin and ceftazidime as compared to imipenem and piperacillin. In all 65 (90.3%) isolates showed multiple drug resistance. Correlation between multidrug resistance and biofilm formation was analysed statistically and p-value was found to be significant (p-value = 0.0004; p-value <0.05 is significant by Chi -Square Test). Conclusion: The study concludes that there a positive correlation between biofilm formation and multiple drug resistance in A. baumannii.