Frequency of typhoidal and non-typhoidal salmonella species and detection of their drugs resistance patterns.

BACKGROUND: To determine the prevalence of typhoidal and non-typhoidal Salmonella species in Hamadan City, west of Iarn and detection of antibiotic susceptibility patterns of isolates.
METHODS: In a cross-sectional descriptive study, 296 Salmonella species including 192 strains of typhoidal Salmonella and 104 strains of non- typhoidal Salmonella were examined for serotyping and determining of antibiotic susceptibility. The strains were collected from patients referred to cilinical centers in Hamadan during 2001 to 2004. They were serotyped and then tested for their antibiotic susceptibility patterns, using Stokes disc diffusion method for 8 antibiotics.
RESULTS: Among 296 samples, 64.8% were typhoidal and 35.2% were non-typhoidal Salmonella species. Typhoidal Salmonella species were as follows: S. typhi 45.6%, S. paratyphi B 8.1%, S. paratyphi C 7.1% and S. paratyphi a 4.7%. Non-typhoidal Salmonella species were as follows: S.typhimurium 21.2%, S.enteritidis 4.4%, S. species 2.1%, S. cholerasuis 1.7%, S. arizona 1.3%, S. agona 1.1%, S. thompson 0.7%, S.muenchen, S.lexington and S. hirschfeldii 0.35%. A proportion of strains ( > 60%) were resistance to cefotaxime and ampicillin. Resistance to ciprofloxacin and amikacin was very low ( < 15%). S.typhimurim (100%), S. typhi (95.7%) S. paratyphi B (89.2%) and S. enteitidis (60%) showed multi-drug resistance.
CONCLUSION: S. typhi and S. typhimurium were the most predominant serotypes in this area. Most of the Salmonella species isolated from patients were resistant to beta-lactam antibiotics and co-trimoxazole, whereas, most of them were sensitive to ciprofloxacin, gentamicin and amikacin. As the prevalence of multidrug-resistant serovar Typhi increases, newer, more expensive, and less readily available antimicrobial agents will be required for the treatment of typhoid.