Invasive Salmonella infections among children in Bintulu, Sarawak, Malaysian Borneo: a 6-year retrospective review

BACKGROUND: Invasive Salmonella infections result in significant morbidity and mortality in developing countries. In Asia, typhoid and paratyphoid fever are reported to be the major invasive Salmonella infections, while invasive non-typhoidal Salmonella (iNTS) infections are believed to be uncommon. Data from Sarawak, in Malaysian Borneo, are limited. METHODS: A retrospective study identifying all children aged < 15 years with invasive Salmonella infections from 2011 to 2016 was conducted in Bintulu Hospital in Sarawak. Population incidences, clinical and bacterial characteristics were examined. RESULTS: Forty-four patients were identified during the 6-year study period: 43 had iNTS infection and 1 had typhoid fever. The average annual iNTS incidence was 32.4 per 100,000 children aged < 5 years. None of the children had malaria or HIV infection, and only 7% were severely malnourished. Salmonella Enteritidis and Salmonella Java were the commonest NTS serovars identified. Pneumonia was the most common manifestation of iNTS disease, present in 20 (47%) children. Other manifestations included gastroenteritis, fever without a source, septic arthritis and meningitis. Salmonella Enteritidis was identified in 76% of those with pneumonia, significantly more frequently than in children with other manifestations. Over 25% of children with iNTS developed severe disease and nearly 10% suffered long term morbidity or mortality. While 78% of Salmonella Java isolates were multi-drug resistant, nearly all other isolates were susceptible to most antimicrobials, including ampicillin. CONCLUSIONS: Bintulu Division in Sarawak observed a very high incidence of childhood iNTS infections. Enteric fever was uncommon. The epidemiology of invasive Salmonella infections in Malaysian Borneo differs considerably from that of neighbouring countries in Asia.