Salmonella typhi: Antibiotic sensitivity pattern in Dubai, United Arab Emirates

Objective: Drug resistant typhoid fever is a major clinical problem. The object of this study was to determine the sensitivity pattern of various drugs used for treatment of typhoid fever.
Methodology: This was a hospital based descriptive study, conducted from April 2007- May 2009 at the Infectious Diseases Unit and Medical wards, Rashid hospital Dubai, UAE. Only those patients whose blood culture yielded Salmonella typhi were included in the study. The antibiotic susceptibility testing was performed on pure culture by two available methods; broth dilution by VITEK II automated Microbiology system and Disc Diffusion technique. The results were interpreted using Clinical and Laboratory Standards Institute (CLSI) standards. Sensitivity results were reported as sensitive or resistant based on CLSI criteria.
Results: A total of 118 patients fulfilled the inclusion criteria with the mean age + SD 29.2+7.9 years, 86.4% were males and 13.5% females. Most (94.9%) of the patients were expatriates and belong to the developing countries. The history of recent travel (within a month) to endemic areas was positive in 79.6%. The sensitivity pattern showed that the resistance rate was highest for Nalidix acid (71.5%), followed by Chloramphenicol (37.5%), Ampicillin (34.8%), Co-trimaxazole (30.7%), Augmentin (14%) and Ciprofloxacin (6%). Among the sixty four S.typhi tested for Chloramphenicol sensitivity; 30.2% isolates were found to be multi-drug resistant (i.e. resistant to Chloramphenicol, Ampicillin and Co-trimaxazole). Whereas, all the S.typhi isolates were sensitive to third generation Cephalosporins, Amikacin, Gentamycin, Tazocin and Meropenem.
Conclusion: In this study, we observed that the significant percentage of S.typhi is still resistant to the primary drugs. Whereas, the Quinolones and third generation Cephalosporins are potentially effective drugs against S.typhi, however, the increasing resistance to the Quinolones is a matter of concern.