Detection of invA Gene by PCR and Identification with Susceptibility Pattern Evaluation by VITEK 2 of Salmonella Isolates

Abstract

Abstract Typhoidal and non-typhoidal Salmonella is a healthcare concern all over the world, particularly in South Asia with great disease incidents. This study aims to identify and antimicrobial susceptibility testing of hospital wastewater in Dhaka city. Total 134 Salmonellaisolates were identified using cultural characteristics, automated biochemical test, and PCR for invA gene detection. Biochemical identification and Antimicrobial Susceptibility Test (AST) were performed through VITEK 2. Essential Agreement (EA) and Categorical Agreement (CA) were worked out according to the CLSI breakpoint. We also measured Very Major Error (VME), Major Error (ME), and Minor Error (mE). Seven Salmonella serotypes were identified through VITEK 2 ID-GN card and invAgene detection. S. Typhimurium, S. Paratyphi, S. Enteritidis, S. Enterica, and S. Typhi were most predominant, while S. Gallinarum and S. Arizonae were less common serovar. Among 136 isolates, 134 (98.5%) were correctly identified to the species level. Accordingly, 47% (64 out of 136), 29% (39 out of 136), 10.29% (14 out of 136), and 12.5% (17 out of 136) isolates were identified within the excellent, very good, good, and acceptable levels. Moreover, we found that 87% of isolates (116 out of 134) exerted at least resistance to one antibiotic. Of 134 tested isolates, there were 7 serotypes that showed Very Major Error (VME). The final Major Error (ME) and Minor Error (mE) shown organisms were 15 and 67. Overall 98.86% Essential Agreement (EA)and 95.95% Categorical Agreement (CA)was calculated for microbes versus antimicrobial agent. The most common resistance pattern of multi-resistant serovares was to ampicillin, chloramphenicol, sulphonamide, and trimethoprim. The study implies that the VITEK 2 system recounts an accurate, acceptable, and reliable result. Ongoing research is a matter of concern for emerging multi-drug resistance of Salmonella serovares and helpful evidence for healthcare provider.