Biofilm formation by carbapenem-resistant Enterobacteriaceae strains isolated from surveillance cultures in Intensive Care Unit patients: A significant problem

Background: Carbapenem-resistant Enterobacteriaceae (CRE) is a serious global public health threat. Antibiotic overuse, improper sanitation and unhygienic practices lead to large scale carriage and rapid spread. Biofilm formation by these strains can lead to far reaching consequences. Material and Method: This is a prospective hospital based study planned for a period of 3 months including all patients admitted to 14 bedded Trauma ICU of a tertiary care hospital in Rajasthan. Rectal swabs were collected from admitted patients and carriage of carbapenem resistant enterobacteriaceae looked for as per CDC guidelines. Screening of the Enterobacteriaceae colonies for carbapenemase production was done by Modified Hodge test. Carbapenem-resistant isolates were also tested for Metallobetalactamase production by phenotypic disc confirmatory test. Biofilm formation testing was done by Tissue culture plate method. Results: A total of 73 patients were screened and 27 CRE isolates were obtained, carriage rate being 37%. A high level of resistance was seen to aminoglycosides, fluoroquinolones and cephalosporins. 100% sensitivity was however seen to Colistin, Tigecycline and Fosfomycin. 5 out of 27 strains showed a positive MHT test. Metallo beta lactamase (MBL) production was seen in 21/25 strains as tested by meropenem and meropenem-edta discs. Of the 27 CRE isolates tested for biofilm production, 13 (48.15%) were found positive. Conclusion: The current study finds out the prevalence of CRE carriage and the biofilm forming potential of these strains among critically ill patients and stresses upon urgent need for stringent infection control measures.