Typhoid Fever in Africa: Emerging Flouroquinolone Resistance S KARIUKI 1,3, G REVATHI 2, J MUYODI 1, J MWITURIA 1, A MUNYALO 1, S MIRZA 3, CA HART 3 1 Centre for Microbiology Research, KEMRI, Kenya, 2 Department of Medical Microbiology, Kenyatta National Hospital, Kenya, 3 Department of Medical Microbiology and Genito-Urinary Medicine, Liverpool, UK.

Introduction Salmonella Typhi : cause >10 million cases, 600,000 deaths / year, mainly in developing countries. Comprise 8-10% of all Salmonella serotype isolations in Kenya. MDR S. Typhi increasingly reported in Africa; chloramphenicol, ampicillin or cotrimoxazole increasingly ineffective.

Methods Between 1999 – 2000: 140 S. Typhi from blood cultures of adults (104) and children (36). 3 different regions of the country.

Methods Identification by serotype and phage type Antibiotic susceptibility testing - MIC using E- test method Plasmid isolation and in-vitro conjugation tests Genomic DNA characterisation by PFGE

Methods PCR PCR of RepHI1A replicon, present in IncHI plasmids PCR of gyrA, gyrB, parC and parE genes within QRDR Digestion with 5 U of Hinf I – determine HinfI mutations in gyrA site

RESULTS Antimicrobial susceptibility Only 19/140 (13.7%) fully susceptible to all drugs tested. 82.3% were MDR Strains high MICs Ampicillin,chloramphenicol, tetracycline, (MICs > 256µg/ml), streptomycin (MIC > 1024µg/ml) and cotrimoxazole (MIC> 32µg/ml)

RESULTS MICs for Quinolones n=140

RESULTS Phenotypes and Genotypes of S. Typhi

RESULTS PCR of QRDR No resultant mutations observed after sequencing PCR products of high Quinolone MIC strains.

Plasmids Resistance encoded on a 110-kb self- transferable plasmid of incHI1 incompatibility group. Increase in MICs of the quinolones had not resulted from any significant mutation

Inc groups of S. Typhi M 365 bp

Genotypes of S. Typhi M

Conclusions Prior to 1991, all S. Typhi were fully susceptible to Abs Resistance 1 st seen 1992, at 25% 1997 at 68% steadily rising to 76% by 2002.

CONCLUSIONS Two main genotypes in circulation – both S and R strains. Nal R and Cipro high MIC strains (47%) have 10X MIC of sensitive strains Rx failures already being observed even within sensitive MIC bracket.

References 1. Kariuki S, Revathi G, Muyodi J, Mwituria J, Munyalo A, Mirza S, Hart CA. Characterization of multidrug-resistant typhoid outbreaks in Kenya. J Clin Microbiol Apr;42(4): Kariuki S, Gilks C, Revathi G, Hart CA. Genotypic analysis of multidrug-resistant Salmonella enterica Serovar typhi, Kenya. Emerg Infect Dis Nov-Dec;6(6): Kariuki S, Hart CA. Global aspects of antimicrobial-resistant enteric bacteria. Curr Opin Infect Dis Oct;14(5):