Culture dependent and independent detection of multiple extended beta-lactamase producing and biofilm forming Salmonella species from leafy vegetables

Abstract

The current study aimed to determine the presence of extended-spectrum beta-lactamase (ESBL) producing Salmonella species isolated from green leafy vegetables in coastal India through a rapid culture-independent method. Salmonella sp. from leaf samples were preliminarily screened for the presence of ESBL genes such as blaCTX-M, blaSHV, blaTEM and blaOXA . The multidrug resistance pattern was determined by the disk diffusion test and the susceptibility of the species was evaluated against 12 antimicrobials from four different classes. The highest rates of resistance were against Penicillin G (100%) and Ampicillin (100%) followed by Amoxicillin (80%) respectively. In contrast, all the bacteria showed sensitivity to Ciprofloxacin. In this study, high rates of multidrug resistance and ESBL production were observed in Salmonella species. All the isolates also exhibited swimming and swarming motility along with the ability to produce biofilms. Culture independent analysis carried out with the leaf samples revealed a presence of a high number of tested ESBL genes in all four samples with a significantly high number in coriander leaf samples. Results indicate that the currently developed method is a good alternative to existing screening techniques owing to its rapid and efficient differentiation of ESBLs. • High rates of multidrug resistance and ESBL production were observed in Salmonella species. • Salmonella species showed swimming and swarming motility along with the ability to produce biofilms. • Culture independent analysis revealed a presence of a high number of tested ESBL genes in coriander leaf samples.