The present study examined the anti-biofilm efficacy of two short-chain antimicrobial peptides (AMPs), namely, indolicidin and cecropin A (1-7)-melittin (CAMA) against biofilm-forming multidrug-resistant enteroaggregative Escherichia coli (MDR-EAEC) isolates. The typical EAEC isolates re-validated by PCR and confirmed using HEp-2 cell adherence assay was subjected to antibiotic susceptibility testing to confirm its MDR status. The biofilm-forming ability of MDR-EAEC isolates was assessed by Congo red binding, microtitre plate assays and hydrophobicity index; broth microdilution technique was employed to determine minimum inhibitory concentrations (MICs) and minimum biofilm eradication concentrations (MBECs). The obtained MIC and MBEC values for both AMPs were evaluated alone and in combination against MDR-EAEC biofilms using crystal violet (CV) staining and confocal microscopy-based live/dead cell quantification methods. All the three MDR-EAEC strains revealed weak to strong biofilm-forming ability and were found to be electron-donating and weakly electron-accepting (hydrophobicity index). Also, highly significant (P < 0.001) time-dependent hydrodynamic growth of the three MDR-EAEC strains was observed at 48 h of incubation in Dulbecco’s modified Eagle’s medium (DMEM) containing 0.45% D-glucose. AMPs and their combination were able to inhibit the initial biofilm formation at 24 h and 48 h as evidenced by CV staining and confocal quantification. Further, the application of AMPs (individually and combination) against the preformed MDR-EAEC biofilms resulted in highly significant eradication (P < 0.001) at 24 h post treatment. However, significant differences were not observed between AMP treatments (individually or in combination). The AMPs seem to be an effective candidates for further investigations such as safety, stability and appropriate biofilm-forming MDR-EAEC animal models.

Cholera caused by Vibrio cholerae is a major public health problem among developing countries. The present study is designed to understand the occurrence of V. cholerae using conventional as well as molecular tools and antibiotic susceptibility testing of the isolated strains of V. cholerae from Muttil panchayat in district Wayanad of Kerala, India. This study was undertaken for a period of 12 months i.e., from April 2014 to March 2015. Out of 60 water samples collected from stream, 38 (63.3 %) were found positive for V. cholerae by conventional methods and among these, 21 (35 %) samples were found positive by PCR. However, none of the water samples (well water, household drinking water and pipeline water) yielded V. cholerae. The presence of V. cholerae was observed in the soil and stream from residential area and were also isolated from fish samples as well as from human stool samples. The antibiotic susceptibility testing of the isolates of V. cholerae obtained from different types of samples exhibited 100 % resistance to the antibiotics under study except for doxycycline. Furthermore, on correlating the physical parameters of the water samples collected with the isolation of V. cholerae, it was found that optimum temperature, increased pH and salinity in the present study favoured the survival of V. cholerae, along with high biochemical oxygen demand values of the water samples. The present study provides a baseline data to devise rapid and reliable molecular detection methods for V. cholerae and thereby attaining concrete molecular epidemiological surveillance.

We explored and evaluated for the first time colorimetric nitrocefin assay in conjunction with the double disc test and PCR assay. We suggested the use of nitrocefin assay for rapid screening of ESBL-production by Enteroaggregative Escherichia coli.

Seaf Seafoods are prone to bacterial contamination and could cause health risk to consumers. The present study was aimed to detect the occurrence of Listeria monocytogenes and Salmonella spp. in seafood collected from different retail markets in Kalpetta, Vythiri and Chundale areas of Wayanad district, Kerala. A total of 80 seafood samples (36 fish, 13 prawn, 08 squid, 11 crabs and 12 mussels) were screened by cultural method to isolate and identify L. monocytogenes and Salmonella spp. Molecular identification of isolates was carried out by Polymerase Chain Reaction P The results revealed that L. monocytogenes was recovered from six (7.5%) seafood samples three from fish, one each from prawn, squid and mussel, whereas Salmonella spp. was detected in four (5%) samples which included two from fish, one each from squid and mussel. Prevalence of L. monocytogenes and Salmonella spp. in raw seafood may pose health risk for consumers.