Defining the burden of morbidity and mortality due to invasive Staphylococcus aureus disease and the impact of drug resistance in Thailand

Abstract

A retrospective study of Staphylococcus aureus bacteraemia in a provincial hospital in northeast Thailand established that S. aureus was responsible for considerable morbidity and mortality. A prospective study of 270 patients with invasive S. aureus infection in the same hospital showed that the range of clinical manifestations was broad and comparable to that in developed countries. All-cause and S. aureus-attributable mortality rates were 26% and 20%, respectively. Multiple logistic regression analysis revealed that age, underlying cardiac disease and respiratory infection were risk factors for all-cause and S. aureus-attributable mortality, while abscesses and procedures for infectious source control were associated with survival. Patients infected by Panton-Valentine Leukocidin (PVL) gene-positive isolates had a strong survival advantage compared with patients infected by PVL gene-negative isolates. Evaluation of the patient sub-set with bacteraemia (n=98) demonstrated that the prevalence of endocarditis was similar to developed countries (14%), but that the all-cause and attributable mortality rates were considerably higher (52% and 44%, respectively). Methicillin-resistant S. aureus (MRSA) was responsible for 28% of bacteraemias, all of which were healthcare-associated. MRSA were multidrug resistant, and the proportion of MRSA-infected patients with bacteraemia prescribed an effective antimicrobial prior to culture results becoming available was low (15%). A subset of 73 patients with severe sepsis due to S. aureus bacteraemia was examined to consider why death occurred and how, by drawing on the ‘Surviving Sepsis Campaign’ guidelines, these might be prevented. Key findings were that the core elements of the guidelines were within the current resource capability of the hospital. A prospective study of rates of MRSA carriage and acquisition in 2 intensive care units demonstrated high rates of transmission and low compliance with hand-washing. In summary, S. aureus disease is an important pathogen in provincial Thailand and is probably responsible for a significant burden of disease across resource-restricted Asia.