Typhoid in Laos: An 18-Year Perspective

Abstract

Although typhoid is endemic to Southeast Asia, very little is known about the disease in Laos. Typhoid vaccination is not included in the national immunization program. Although sanitation has improved, one million people still do not have access to basic clean water sources. We describe the epidemiology and antimicrobial susceptibility patterns of Salmonella enterica serovar Typhi (S. Typhi) infection in Laos based on isolates accrued over 18 years at Mahosot Hospital, Vientiane. All blood cultures collected from patients presenting with fever submitted to the Microbiology Laboratory at Mahosot Hospital (February 2000-December 2018) were included. This included patients from Vientiane and four provincial hospitals and one typhoid outbreak investigation. A total of 913 (1.5%) of 60,384 blood cultures were positive for S. Typhi. The majority of isolates with data available (712/898, 79.3%) were susceptible to all antibiotics tested, with 59 (6.5%) multidrug-resistant (MDR) isolates, mostly from one outbreak. Of 854 isolates, 12 (1.4%) were fluoroquinolone resistant. Patient admissions peaked between March and June at the end of the dry season. Although there are key limitations, these data give the first detailed epidemiological evidence of typhoid in Laos. However, estimates will be greatly influenced by access to blood culture services and health-seeking behavior. Although typhoid multidrug resistance and fluoroquinolone resistance are not currently major issues in Laos, continued surveillance and improved antibiotic stewardship are necessary to forestall worsening of the situation. Cost-effectiveness analysis is needed to inform decisions regarding typhoid vaccine introduction.

Salmonella Typhi and Salmonella Paratyphi prevalence, antimicrobial susceptibility profile and factors associated with enteric fever infection in Bahir Dar, Ethiopia

“…Typhi and S . Paratyphi A isolates in the present study were resistant for cotrimoxazole which was comparable with studies in Nigeria 36 , and Laos 33 but higher than study in India 30 , 42 . This variation might be due to study period and setting difference.…”

“…Though the MDR level of S . Typhi in the present study was comparable with a study in Bangladesh (64.28%) 41 , it was higher than many previous studies in Ethiopia 19 , and elsewhere such as Egypt, Nigeria, Asian countries, India, and Laos 28 , 32 , 33 , 36 , 42 which reported 0 to 29%. Similarly the MDR level of S .…”

“…But the prevalence of EF in the present study was higher than a study done in Ethiopia 18 , India 12 , 29 , 30 , Fiji 13 , and Nepal 15 reporting 2.7%, 0.22–1.24%, 0.7%, and 2.5% respectively. Similarly lower TF prevalence than the present study was reported by previous studies done in Cameroon (2.5%), Asian countries (2%), India (0.14%), and Laos (1.5%) 29 , 31 – 33 . This could be due to variations in S .…”

“…The resistance level for chloramphenicol in both isolated bacteria in the present study was comparable with previous studies 19 but higher than previous reports for S . Typhi 16 , 28 , 30 , 33 , 36 , 41 , 42 and S . Paratyphi 16 , 36 , 42 .…”

Estimation of Incidence of Typhoid and Paratyphoid Fever in Vientiane, Lao People’s Democratic Republic

“…In a parallel study, we used the data from blood cultures received at Mahosot Hospital, Vientiane, from diverse parts of Laos, to provide a minimal estimate of inpatient culturepositive typhoid incidence, with the most recent annual incidence in 2018 of 0.59 cases per 100,000 persons in the community. 11 However, because of limitations of access to Mahosot Hospital from remote areas and few blood culture services outside Vientiane, this estimate of annual incidence of hospitalized typhoid is likely to be a substantial underestimate of the true incidence of the disease in the community.…”