Antimicrobial resistance pattern of Salmonella enterica servars in Southern Delhi

Abstract

Background: Enteric fever is predominantly caused by serovars Typhi and Paratyphi of Salmonella enterica . Recently upsurge in multidrug resistant typhoid fever has become a major public health concern in developing countries. This study was conducted to determine the sensitivity pattern of S. Typhi and S. Paratyphi in Southern Delhi. Methods: A total of 98 Salmonella species were isolated over a period of two years between March 2012 – March 2014. Diagnosis of patients was based on clinical features, blood culture and serology. Blood samples were collected and incubated in BacT alert 3D system. Identification was done and antibiotic susceptibility was done by conventional methods and cross checked by Vitek 2 compact system. Results: Of the 98 isolates 87 (88.7 %) were S. Typhi and 11 (11.22%) were S. Paratyphi. Out of 87 samples from which S. Typhi was isolated (68) 78% were male and (19) 21.8% were female patients and they belonged to all age groups. Fever was present in all patients. In this study high resistance was found for both S. Typhi and S. Paratyphi respectively for third generation cephalosporins ( 35.6%, 54.5%), good  sensitivity  for macrolides (90.8% & 100%) and average sensitivity for ofloxacin (81.6% & 63.7%).  Ampicillin and chloramphenicol shows lesser resistance i.e. (11.5% & 18.1%) and (12.6% and 27.2%). 3.5% and 0% resistance was found for imipinem and  tigecycline was found 100% sensitive for both S. Typhi and S. Paratyphi, used rarely in treatment of typhoid fever. None of the strains were found sensitive to all drugs. Conclusion: Typhoid bacilli keeps changing its antimicrobial susceptibility pattern. Currently newer drugs like tigecyclline, imipenem and macrolide are showing great response. Primary drugs are showing less resistance may be due to their infrequent usage whereas cephalosporins are showing high resistance towards typhoid bacilli. For better treatment it is important to know the recent susceptibility trend of the area.