Prevalence of multidrug-resistant Salmonella enteric serotype typhi and paratyphi A of human cases from the Tiruchirappalli district, India, and their associated virulent markers

Abstract

Aim The study sought to determine the multidrug resistance (MDR) of Salmonella enterica typhi and paratyphi A isolates in correlation with the presence of virulent markers detected by a PCR-based approach. Methods Blood and stool samples were collected from suspected cases and further confirmation was done serologically and bacteriologically. The isolated strains were clustered using RAPD analysis. The multidrug resistance pattern of the isolates was checked against a panel of antibiotics and screened for the presence of biochemical and molecular virulent markers including fimA and stn by PCR methods. Results In total 368 suspected cases were identified. The geographical distribution showed 84 cases from the north zone (Lalgudi), 110 from the south zone (Palakarai), 91 from the east zone (Mattur and Tiruverambur) and 83 from the west zone (Petavaithalai). Among the 368 suspected cases, 349 (94.8%) and 177 (48.13%) cases were confirmed as typhoid fever serologically and bacteriologically, respectively. The clinical sample culturing yielded 144 isolates, of which 117 were S. typhi and 27 were S. paratyphi A. Both S. typhi and S. paratyphi A showed an absolute resistance pattern (100%) against chloramphenicol, erythromycin and tetracycline with next higher incidence of resistance against nalidixic acid and streptomycin. Irrespective of the presence of biochemical markers, all MDR strains showed the presence of fimA and stn. Conclusion No resistance pattern was observed for ceftriaxone, cephotaxime and co-trimoxazole. Thus, in this regard, the above-mentioned antibiotics can be used for the effective treatment of typhoid fever in this study locality. Molecular fingerprinting led to the hypothesis of diverse routes of Salmonella transmission and a putative high virulence potential for the isolates characterized.

Prevalence of Multidrug-Resistant (MDR) Salmonella enteritidis in Poultry and Backyard Chicken from Tiruchirappalli, India

“…Such an outbreak implied that the animal products that are locally available would have been contaminated with S. typhi envisaging a transmission to humans through the consumption of contaminated animal products (Sathiamoorthi et al, 2011). Thus, one such possible route of transmission can be attributed to the use of poultry chicken from the retail outlets of Tiruchirappalli.…”

“…The strains were streaked on the agar plates and incubated for 18-48 h at 37°C for the formation of halo zones around the colonies. The enzyme activities were measured by subtracting the diameter of the colony from the total zone diameter as described earlier (Sathiamoorthi et al, 2011).…”