BackgroundMost 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.MethodsA 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 FindingsNinety-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.

We describe and validate a novel PCR assay to detect the pandemic hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA) lineage ST 239. Results based on previously uncharacterized isolates from a hospital in northeast Thailand support the view that at least 90% of HA-MRSA isolates in mainland Asia correspond to ST 239 or close relatives.Methicillin-resistant Staphylococcus aureus (MRSA) strains constitute a considerable health and resource burden in the hospital environment. Although there is currently a paucity of data (17), the evidence available suggests a high frequency of methicillin resistance throughout mainland Asia (9,14). Two recent papers have used multilocus sequence typing (MLST) to characterize hospital-acquired MRSA (HA-MRSA) isolates from nine Asian countries from Saudi Arabia to the Philippines (4, 15). These data suggest that at least 90% of the cases of HA-MRSA within a region accounting for Ͼ60% of the world's population can be accounted for by a single clonal subgroup, ST 239. This genotype has also been detected in 26 countries outside of Asia, corresponding to the EMRSA-1, -4, -7, -9, and -11, Brazilian (1), Portuguese, Hungarian (8), and Viennese clones, although in many countries, it has recently been replaced by other clones (1,5,7,8,13,16,(18)(19)(20).The global dissemination of this clone is consistent with heightened transmissibility, and two recent reports noted an association between ST 239 and increased virulence (2, 10). ST 239 has evolved through a large-scale recombination event involving the import of ϳ20% of the genome from CC 30 (ST 30-like), while the remaining 80% (genomic backbone) corresponds to CC 8 (ST 8-like) (21). As these two lineages are unrelated (6), this mosaic structure provides the means to develop a rapid, accurate, and sensitive PCR-based assay. We designed two pairs of discriminatory nonredundant primers based on two variable genes, one of which (SA2003) lies within the ST 8-like backbone, while the other (SA0317) lies within the ST 30-like imported region (21) (Fig. 1). As the primers were designed to amplify products of different sizes (220 bp for SA2003 and 484 bp for SA0317), it is possible to identify cases where both products are amplified from a single PCR. The presence of both amplicons of the predicted sizes indicates the presence of both the ST 30-and ST 8-like sequences in the hybrid genome of ST 239.The primer sequences used were ST 239/ST 30-like specific primers 5Ј-TCGCACTCTCGTTGAACA-3Ј (SA0317Forward) and 5Ј-AAATCCGCTTCGACAAACATT (SA0317Reverse) (Fig. 1) and ST 239/ST 8-like specific primers 5Ј-CACTTTAAATA CTGACGAAAAT-3Ј (SA2003Forward) and 5Ј-TTGAAAAT TGATCATTCAGCAA-3Ј (SA2003Reverse).Heteroduplex PCR was carried in a 25-l mixture consisting of 1ϫ PCR buffer, 1.5 mM MgCl 2 , 0.2 mM deoxynucleoside triphosphate, 0.7 M of each of the four primers, 1.25 U of HotStart Taq DNA polymerase, and 2.5 l of DNA. PCR conditions were 95°C for 15 min; 30 cycles of 95°C for 30 s, 55°C for 30 s, and 72°C for 30 s; and 72°C for 7 min. Figu...

Methicillin-resistant Staphylococcus aureus (MRSA) transmission in the hospital setting has been a frequent subject of investigation using bacterial genomes, but previous approaches have not yet fully utilised the extra deductive power provided when multiple pathogen samples are acquired from each host. Here, we used a large dataset of MRSA sequences from multiply-sampled patients to reconstruct colonisation of individuals in a high-transmission setting in a hospital in Thailand. We reconstructed transmission trees for MRSA. We also investigated transmission between anatomical sites on the same individual, finding that this either occurs repeatedly or involves a wide transmission bottleneck. We examined the between-subject bottleneck, finding considerable variation in the amount of diversity transmitted. Finally, we compared our approach to the simpler method of identifying transmission pairs using single nucleotide polymorphism (SNP) counts. This suggested that the optimum threshold for identifying a pair is 39 SNPs, if sensitivities and specificities are equally weighted.

BackgroundThe Surviving Sepsis Campaign (SSC) guidelines describe best practice for the management of severe sepsis and septic shock in developed countries, but most deaths from sepsis occur where healthcare is not sufficiently resourced to implement them. Our objective was to define the feasibility and basis for modified guidelines in a resource-restricted setting.Methods and FindingsWe undertook a detailed assessment of sepsis management in a prospective cohort of patients with severe sepsis caused by a single pathogen in a 1,100-bed hospital in lower-middle income Thailand. We compared their management with the SSC guidelines to identify care bundles based on existing capabilities or additional activities that could be undertaken at zero or low cost. We identified 72 patients with severe sepsis or septic shock associated with S. aureus bacteraemia, 38 (53%) of who died within 28 days. One third of patients were treated in intensive care units (ICUs). Numerous interventions described by the SSC guidelines fell within existing capabilities, but their implementation was highly variable. Care available to patients on general wards covered the fundamental principles of sepsis management, including non-invasive patient monitoring, antimicrobial administration and intravenous fluid resuscitation. We described two additive care bundles, one for general wards and the second for ICUs, that if consistently performed would be predicted to improve outcome from severe sepsis.ConclusionIt is feasible to implement modified sepsis guidelines that are scaled to resource availability, and that could save lives prior to the publication of international guidelines for developing countries.

Background:The Surviving Sepsis Campaign (SSC) guidelines describe best practice for the management of severe sepsis and septic shock in developed countries, but most deaths from sepsis occur where healthcare is not sufficiently resourced to implement them. Our objective was to define the feasibility and basis for modified guidelines in a resource-restricted setting. Methods and Findings:We undertook a detailed assessment of sepsis management in a prospective cohort of patients with severe sepsis caused by a single pathogen in a 1,100-bed hospital in lower-middle income Thailand. We compared their management with the SSC guidelines to identify care bundles based on existing capabilities or additional activities that could be undertaken at zero or low cost. We identified 72 patients with severe sepsis or septic shock associated with S. aureus bacteraemia, 38 (53%) of who died within 28 days. One third of patients were treated in intensive care units (ICUs). Numerous interventions described by the SSC guidelines fell within existing capabilities, but their implementation was highly variable. Care available to patients on general wards covered the fundamental principles of sepsis management, including non-invasive patient monitoring, antimicrobial administration and intravenous fluid resuscitation. We described two additive care bundles, one for general wards and the second for ICUs, that if consistently performed would be predicted to improve outcome from severe sepsis. Conclusion:It is feasible to implement modified sepsis guidelines that are scaled to resource availability, and that could save lives prior to the publication of international guidelines for developing countries.