Characterization of Multidrug-Resistant Typhoid Outbreaks in Kenya

Abstract

We characterized by antibiotic susceptibility, plasmid analysis, incompatibility grouping, and pulsed-field gel electrophoresis (PFGE) of XbaI-and SpeI-digested DNA 102 Salmonella enterica serovar Typhi (serovar Typhi) isolated from recent outbreaks of typhoid in three different parts of Kenya. Only 13.7% were fully susceptible, whereas another 82.4% were resistant to each of the five commonly available drugs: ampicillin, chloramphenicol, and tetracycline (MICs of >256 g/ml); streptomycin (MIC, >1,024 g/ml); and cotrimoxazole (MIC of >32 g/ml). Resistance to these antibiotics was encoded on a 110-kb self-transferable plasmid of IncHI1 incompatibility group. The MICs of nalidixic acid (MIC, 8 to 16 g/ml) and ciprofloxacin (MIC of 0.25 to 0.38 g/ml) for 41.7% of the 102 serovar Typhi isolates were 5-and 10-fold higher, respectively, than for sensitive strains. Amplification by PCR and sequencing of the genes coding for gyrase (gyrA and gyrB) and topoisomerase IV (parE and parC) within the quinolone resistance-determining region revealed that the increase in the MICs of the quinolones had not resulted from any significant mutation. Analysis of genomic DNA from both antimicrobial agent-sensitive and multidrug-resistant serovar Typhi by PFGE identified two distinct subtypes that were in circulation in the three different parts of Kenya. As the prevalence of multidrugresistant serovar Typhi increases, newer, more expensive, and less readily available antimicrobial agents will be required for the treatment of typhoid in Kenya.

Typhoid fever in sub-Saharan Africa: Challenges of diagnosis and management of infections

“…Since the first report of MDR serovar Typhi outbreaks, which occurred in Kenya in 1997 to 1999 [18] when the prevalence of the MDR phenotype was 50 to 65%, our current hospital-based surveillance has shown that only 13.7% isolates were fully susceptible to all drugs tested, while 75-82% of S. Typhi from blood cultures and CSF are MDR with particularly high MICs of ampicillin, chloramphenicol, tetracycline, (MICs > 256µg/ml), streptomycin (MIC > 1024µg/ml) and cotrimoxazole (MIC> 32µg/ml) [7]. In all the isolates showing this multidrug resistance phenotype, a self-transferable large plasmid approximately 110 kb of incompatibility group HI1 was associated with encoding the resistance.…”

“…A breakdown in the portable water system in a South African suburb caused an outbreak of typhoid , causing illness in nearly 4,000 persons as well as several deaths [6]. In Kenya, multidrug-resistant (MDR) S. Typhi strains in adults and school-age children were previously associated with sporadic outbreaks in resource-poor settings [7].…”

Investigation of an outbreak of Salmonella Typhi in Battalgazi district, Malatya-Turkey

“…Multiple antibioticresistant strains for primary drugs (ampicillin, chloramphenicol, co-trimoxazole and tetracycline) have been reported in many countries (4,10,15,17,19). In this study, isolated strains were mostly sensitive with no ESBL ones.…”

“…This bacterium is endemic in many parts of world causing typhoid fever (2,4,7,11,18). Typhoid fever is a severe and life-threatening systemic illness transmitted via the fecal-oral route and is a major cause of morbidity and mortality worldwide.…”

Variabilidade genética de amostras de Salmonella Typhi isoladas de surto e de casos esporádicos ocorridos em Belém, Brasil

“…Chandel e Chaudhry (2) encontraram um único clone entre amostras de S. Typhi isoladas na Índia durante cinco anos. Outros autores, como Kariuki et al (8) , também relataram a presença de um surto de febre tifóide no Quênia; já Thong et al (20) observaram aumento da diversidade genética de isolados de S. Typhi na Nova Guiné de 1992 a 1999.…”