Epidemiology and risk factors for endemic typhoid fever in Uzbekistan

Abstract

Summarybackground To investigate the risk factors for infection with endemic typhoid fever in the Samarkand region of Uzbekistan.methods Case-control study of culture-confirmed bloodstream infection with Salmonella Typhi.Patients were compared to age-matched community controls. Salmonella Typhi isolates were tested for antimicrobial susceptibility.results We enrolled 97 patients and 192 controls. The median age of patients was 19 years. In a conditional regression model, consumption of unboiled surface water outside the home [adjusted odds ratio (aOR) ¼ 3.0, 95% confidence interval (CI) ¼ 1.1-8.2], use of antimicrobials in the 2 weeks preceding onset of symptoms (aOR ¼ 12.2, 95% CI 4.0-37.0), and being a student (aOR ¼ 4.0, 95% CI 1.4-11.3) were independently associated with typhoid fever. Routinely washing vegetables (aOR 0.06, 95% CI 0.02-0.2) and dining at a tea-house (aOR 0.4, 95% CI 0.2-1.0) were associated with protection against illness. Salmonella Typhi resistant to ampicillin, chloramphenicol, and trimethoprimsulfamethoxazole was identified in 6 (15%) of 41 isolates tested.conclusions Endemic typhoid fever in Uzbekistan is transmitted by contaminated water. Recent use of antimicrobials also increased risk of infection. Targeted efforts at improving drinking water quality, especially for students and young adults, are likely to decrease transmission of typhoid fever. Measures to decrease the unnecessary use of antimicrobials would be expected to reduce the risk of typhoid fever and decrease the spread of multiple drug-resistant Salmonella Typhi.

Antibiotic resistance among Salmonella enterica serovars Typhi and Paratyphi A in Pakistan (2001-2006)

“…However, typhoid fever in endemic settings has been linked with high-dose exposure from multiple sources and therefore the possibility of an extra-familial source cannot be excluded in such cases [37]. Prior antimicrobial usage is reported to be a risk factor for typhoid [37,38]. However, the impact of such antimicrobials on the resistance pattern of the infecting organisms needs to be considered.…”

The Burden of Enteric Fever

“…While living in a crowded household was independently associated with typhoid fever [13], routinely washing vegetables [14] and using a latrine for defecation [12] has been found to be protective. Overcrowding probably represents a greater opportunity for person-to-person transmission within households.…”

“…Interestingly, while prior antimicrobial use has been shown in multiple epidemiological studies to increase the risk of infection with both antibioticresistant and drug-sensitive serotypes of S. Typhi [14,16,17], two recent case-control studies in Turkey and Bangladesh failed to show such a link [12,13]. It is postulated that, in addition to providing a selective advantage to resistant S. Typhi strains, antimicrobial exposure can lead to prolonged alterations in gastro-intestinal flora and a decreased barrier to bacterial colonisation, lowering the dose of Salmonella necessary to cause infection [18,19].…”

Typhoid fever: a review

“…42 Again, the habit of washing vegetables and compulsory use of sanitary latrine for defecation have been found to prevent typhoid. 41,43 In a case-control study in Indonesia, paratyphoid fever was found to be associated with consumption of food from street vendors. 44 Excessive antibiotic use causes an increased risk of infection with both drug-resistant and drug-sensitive serotypes of S. typhi, 43,45,46 Interestingly, two recent casecontrol studies in Turkey and Bangladesh failed to show such a link.…”

“…41,43 In a case-control study in Indonesia, paratyphoid fever was found to be associated with consumption of food from street vendors. 44 Excessive antibiotic use causes an increased risk of infection with both drug-resistant and drug-sensitive serotypes of S. typhi, 43,45,46 Interestingly, two recent casecontrol studies in Turkey and Bangladesh failed to show such a link. 41,42 Prolonged antimicrobial use can cause changes in gastro-intestinal flora and a decreased barrier to bacterial colonisation, facilitating Salmonella infection.…”