Core genome multi-locus sequence typing as an essential tool in a high-cost livestock-associated meticillin-resistant Staphylococcus aureus CC398 hospital outbreak.

BACKGROUND: Livestock-associated meticillin-resistant Staphylococcus aureus (LA-MRSA) clonal complex (CC) 398 may be transmitted and cause morbidity and mortality in hospitals. The economic cost of stopping hospital transmission of LA-MRSA CC398 is poorly described. Early detection of transmission may limit the extent of the intervention. AIM: To evaluate core genome multi-locus sequence typing (cgMLST) for detecting transmission chains and to estimate the costs for interventions to prevent further spread after discovery of hospital transmission of LA-MRSA CC398. METHODS: Five patients were involved in two episodes of transmission of LA-MRSA CC398 in a hospital. Standard interventions including MRSA screening of patients and healthcare workers were initiated. Whole genome sequences of the five isolates and 17 epidemiologically unrelated MRSA CC398 isolates from other hospitalized patients were analysed by single nucleotide polymorphism (SNP) comparisons and cgMLST. The economic costs of constraining transmission were calculated from relevant sources. FINDINGS: The five isolates suspected to be involved in hospital transmission clustered with ≤2 SNPs in the draft genome sequences with some distance to other isolates. cgMLST allocated the five isolates to the same type, which was different from all but two of the sporadic isolates. Furthermore, cgMLST separated the five transmission isolates from all other isolates. The economic costs of the outbreak interventions exceeded €11,000 per patient. CONCLUSION: LA-MRSA CC398 is transmittable in hospitals, and intervention against transmission may reach considerable costs. cgMLST is useful in surveillance of hospital transmission of LA-MRSA.

Whole-genome sequencing for identification of the source in hospital-acquired Legionnaires' disease.

Acquisition of Legionnaires' disease is a serious complication of hospitalization. Rapid determination of whether or not the infection is caused by strains of Legionella pneumophila in the hospital environment is crucial to avoid further cases. This study investigated the use of whole-genome sequencing to identify the source of infection in hospital-acquired Legionnaires' disease. Phylogenetic analyses showed close relatedness between one patient isolate and a strain found in hospital water, confirming suspicion of nosocomial infection. It was found that whole-genome sequencing can be a useful tool in the investigation of hospital-acquired Legionnaires' disease.

Effect of magnesium infusion on bleeding time in healthy male volunteers.

Intravenous magnesium has proved to be valuable in the treatment of cardiac arrhythmias and eclampsia, but the specific mode of action is not established. In this study the effect of magnesium sulphate (MgSO4) infusion on bleeding time and endogenous prostacyclin (PGI2) production in healthy male volunteers was investigated. Thirty-five males (age 18-30 years) randomized in a double-blind, placebo-controlled, cross-over study were investigated. MgSO4 was given as a bolus (8 mmol, 12 min) followed by continuous infusion (8 mmol in 108 ml saline, 120 min). Control was equal volumes of physiological saline. Heart rate, blood pressure and bleeding time (according to Ivy) were recorded as well as blood concentrations of magnesium and creatinine. Urine PGI2 was analysed as the stable metabolite 6-keto-prostaglandin F1alpha (6-keto-PGF1alpha). Treatment with MgSO4 did not affect bleeding time (MgSO4; 8.4+/-3.5 vs. control 8.0+/-2.7 min) nor the production of PGI2 (MgSO4; 1.2 microg 6-keto-PGF1alpha/g creatinine vs. control; 1.1 microg 6-keto-PGF1alpha/g creatinine). Intravenous infusion of MgSO4 does not affect the PGI2/platelet axis in healthy male volunteers. Studies in patients with endothelium dysfunction and/or concomitant drug therapy are required before the anti-thrombogenic effect of MgSO4 in vivo is discarded.