Factors Predicting and Reducing Mortality in Patients with Invasive Staphylococcus aureus Disease in a Developing Country

Emma K Nickerson,Janjira Thaipadungpanit,Arkhom Arayawichanont,Weera Mahavanakul,Pramot Srisamang,Gumphol Wongsuvan,Aunchalee Thanwisai,Direk Limmathurosakul,Sharon J Peacock,Krupal R Shah,Premjit Amornchai,Vanaporn Wuthiekanun,Nicholas P Day

doi:10.1371/journal.pone.0006512

Abstract

BackgroundInvasive Staphylococcus aureus infection is increasingly recognised as an important cause of serious sepsis across the developing world, with mortality rates higher than those in the developed world. The factors determining mortality in developing countries have not been identified.MethodsA prospective, observational study of invasive S. aureus disease was conducted at a provincial hospital in northeast Thailand over a 1-year period. All-cause and S. aureus-attributable mortality rates were determined, and the relationship was assessed between death and patient characteristics, clinical presentations, antibiotic therapy and resistance, drainage of pus and carriage of genes encoding Panton-Valentine Leukocidin (PVL).Principal FindingsA total of 270 patients with invasive S. aureus infection were recruited. The range of clinical manifestations was broad and comparable to that described in developed countries. All-cause and S. aureus-attributable mortality rates were 26% and 20%, respectively. Early antibiotic therapy and drainage of pus were associated with a survival advantage (both p<0.001) on univariate analysis. Patients infected by a PVL gene-positive isolate (122/248 tested, 49%) had a strong survival advantage compared with patients infected by a PVL gene-negative isolate (all-cause mortality 11% versus 39% respectively, p<0.001). Multiple logistic regression analysis using all variables significant on univariate analysis revealed that age, underlying cardiac disease and respiratory infection were risk factors for all-cause and S. aureus-attributable mortality, while one or more abscesses as the presenting clinical feature and procedures for infectious source control were associated with survival.ConclusionsDrainage of pus and timely antibiotic therapy are key to the successful management of S. aureus infection in the developing world. Defining the presence of genes encoding PVL provides no practical bedside information and draws attention away from identifying verified clinical risk factors and those interventions that save lives.

Highlights

Staphylococcus aureus is increasingly recognised as an important cause of serious sepsis in the developing world, where the associated mortality far exceeds that in developed countries [1,2,3]
Drainage of pus and timely antibiotic therapy are key to the successful management of S. aureus infection in the developing world
Factors associated with poor outcome from S. aureus infection in the developed world include increasing age [6,8], underlying co-morbidities [9], antimicrobial resistance [10], complicated bacteraemia [11], lack of source control [8] including non-removal of intravenous catheters [12], under-dosing of penicillinase antibiotics for methicillin-susceptible S. aureus (MSSA) [8], and delayed antibiotic therapy [13]

Summary

Introduction

Staphylococcus aureus is increasingly recognised as an important cause of serious sepsis in the developing world, where the associated mortality far exceeds that in developed countries [1,2,3]. Factors associated with poor outcome from S. aureus infection in the developed world include increasing age [6,8], underlying co-morbidities [9], antimicrobial resistance [10], complicated (disseminated) bacteraemia [11], lack of source control [8] including non-removal of intravenous catheters [12], under-dosing of penicillinase antibiotics for methicillin-susceptible S. aureus (MSSA) [8], and delayed antibiotic therapy [13]. The factors determining mortality in developing countries have not been identified

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