Concomitant detection of biofilm and metallo-beta-lactamases production in gram-negative bacilli.

ABSTRACT

Carbapenems are mainstay of treating serious multidrug resistant gram-negative biofi lm-based infections. However, recent emergence of metallo-beta-lactamases (ML) producing gram-negative bacilli in different parts of world may be related to gain of virulence factors associated with biofi lm production. Objectives: To explore the association of ML and biofi lm production in various gramnegative bacilli. Materials and Methods: In this study, 110 non-repetitive ceftazidime resistant gram-negative bacilli were evaluated for biofi lm and ML production. Biofi lm forming ability of isolates obtained from various specimens was tested by the tube method. Disks of ceftazidime (30 g) and ceftazidime with ethylenediaminetetraacetic acid (30 g + 750 g, prepared in house) for ML detection were used. Chi-square test was used to study the association between biofi lm and ML production. P value <0.05 was considered signifi cant. Results: 88 (80%) bacilli had shown biofi lm producing ability. The association of biofi lm and ML was signifi cant in cases of non-fermenters as compared to enterobacteriaceae members. Conclusion: The particular combination of virulence factors (biofi lm and ML) in bacteria may be a species specifi c effect which needs to be investigated at molecular level in detail. This may help in designing newer therapies based on interference with biofi lm formation and thus countering clinical episodes of antibiotic resistance.