Staphylococcus aureus Bacteraemia in a Tropical Setting: Patient Outcome and Impact of Antibiotic Resistance

Background: Most information on invasive Staphylococcus aureus infections comes from temperate countries. There are considerable knowledge gaps in epidemiology, treatment, drug resistance and outcome of invasive S. aureus infection in the tropics. Methods: A prospective, observational study of S. aureus bacteraemia was conducted in a 1000-bed regional hospital in northeast Thailand over 1 year. Detailed clinical data were collected and final outcomes determined at 12 weeks, and correlated with antimicrobial susceptibility profiles of infecting isolates. Principal Findings: Ninety-eight patients with S. aureus bacteraemia were recruited. The range of clinical manifestations was similar to that reported from temperate countries. The prevalence of endocarditis was 14%. The disease burden was highest at both extremes of age, whilst mortality increased with age. The all-cause mortality rate was 52%, with a mortality attributable to S. aureus of 44%. Methicillin-resistant S. aureus (MRSA) was responsible for 28% of infections, all of which were healthcare-associated. Mortality rates for MRSA and methicillin-susceptible S. aureus (MSSA) were 67% (18/27) and 46% (33/71), respectively (p = 0.11). MRSA isolates were multidrug resistant. Only vancomycin or fusidic acid would be suitable as empirical treatment options for suspected MRSA infection. Conclusions: S. aureus is a significant pathogen in northeast Thailand, with comparable clinical manifestations and a similar endocarditis prevalence but higher mortality than industrialised countries. S. aureus bacteraemia is frequently associated with exposure to healthcare settings with MRSA causing a considerable burden of disease. Further studies are required to define setting-specific strategies to reduce mortality from S. aureus bacteraemia, prevent MRSA transmission, and to define the burden of S. aureus disease and emergence of drug resistance throughout the developing world. © 2009 Nickerson et al

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

BACKGROUND: Invasive 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. METHODS: A 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 FINDINGS: A 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. CONCLUSIONS: Drainage 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

The effects of a three-week use of lumbosacral orthoses on trunk muscle activity and on the muscular response to trunk perturbations

<p>Abstract</p> <p>Background</p> <p>The effects of lumbosacral orthoses (LSOs) on neuromuscular control of the trunk are not known. There is a concern that wearing LSOs for a long period may adversely alter muscle control, making individuals more susceptible to injury if they discontinue wearing the LSOs. The purpose of this study was to document neuromuscular changes in healthy subjects during a 3-week period while they regularly wore a LSO.</p> <p>Methods</p> <p>Fourteen subjects wore LSOs 3 hrs a day for 3 weeks. Trunk muscle activity prior to and following a quick force release (trunk perturbation) was measured with EMG in 3 sessions on days 0, 7, and 21. A longitudinal, repeated-measures, factorial design was used. Muscle reflex response to trunk perturbations, spine compression force, as well as effective trunk stiffness and damping were dependent variables. The LSO, direction of perturbation, and testing session were the independent variables.</p> <p>Results</p> <p>The LSO significantly (<it>P </it>< 0.001) increased the effective trunk stiffness by 160 Nm/rad (27%) across all directions and testing sessions. The number of antagonist muscles that responded with an onset activity was significantly reduced after 7 days of wearing the LSO, but this difference disappeared on day 21 and is likely not clinically relevant. The average number of agonist muscles switching off following the quick force release was significantly greater with the LSO, compared to without the LSO (<it>P </it>= 0.003).</p> <p>Conclusions</p> <p>The LSO increased trunk stiffness and resulted in a greater number of agonist muscles shutting-off in response to a quick force release. However, these effects did not result in detrimental changes to the neuromuscular function of trunk muscles after 3 weeks of wearing a LSO 3 hours a day by healthy subjects.</p

Timely effective antibiotic therapy and procedures for infectious source control significantly improved outcome.

<p>Administration of an effective antibiotic on the same day as the positive culture was taken significantly reduced all-cause mortality (p<0.001), as did undergoing a procedure for infectious source control (p<0.001).</p

The range of sites of infection in patients and outcome associated with each clinical presentation.

*<p>¹p value for the comparison between all-cause deaths and survivors.</p>*<p>²Site of deep abscesses were muscle (n = 20), retroperitoneal space (n = 7), parotid gland (n = 7), liver (n = 3), lung (n = 2), epidural space (n = 2), eye (n = 2), oropharynx (n = 2) and spleen (n = 1).</p>*<p>³Other skin and soft tissue infections includes: necrotising fasciitis (n = 9), bedsore(s) (n = 6), pustules and carbuncles (n = 5), infected wound from trauma (n = 3), infected wound from tophi (n = 2), gangrene (n = 2), cellulitis (without other skin or soft tissue lesion) (n = 2) and infection of exfoliated skin following a severe drug reaction (n = 2).</p>*<p>⁴Orthopaedic material includes: internal fixation metalwork (n = 8) and a hip replacement (n = 1).</p>*<p>⁵Intravenous devices were peripheral cannulas (n = 4), central catheters (n = 3) and an umbilical catheter (n = 1).</p>*<p>⁶Endocarditis from transthoracic echocardiographic evidence of vegetations (n = 7); 1 case clinically but died prior to echocardiogram.</p>*<p>⁷Other infections include: urinary tract infection (n = 3), tenosynovitis (n = 2), Lemierre's syndrome (n = 1) and corneal ulcer (n = 1).</p>*<p>⁸Post-operative infections include: mediastinitis (n = 4; 3 following mitral valve replacement and 1 after coronary artery bypass graft), meningitis from infected bone flap surgical wound (n = 1) and abdominal wound (n = 1).</p

Significant risk factors for mortality from <i>S. aureus</i> infection from multiple logistic regression analysis.

*<p>¹95% confidence intervals.</p>*<p>²p value from Likelihood ratio test.</p