Vancomycin therapeutics and monitoring: a contemporary approach.

Vancomycin remains a clinically useful antibiotic despite the advent of several alternative drugs. Optimising vancomycin therapy with therapeutic drug monitoring is widely recommended. The aim of therapeutic drug monitoring is to help the clinician to achieve target pharmacodynamic parameters in the case of vancomycin, an area under the concentration time curve/minimum inhibitory concentration ratio of ≥400. Vancomycin monitoring methods can be categorised into four categories: empiric trough concentrations; linear regression analysis (one-compartment model), population methods and Bayesian estimation procedures. Although the empiric trough concentrations and population methods are easy to use and require minimal resources, there are large differences in the published vancomycin model parameters. This demonstrates that there is great variance in pharmacokinetic parameters between the models and a single vancomycin model cannot be applied to all patient populations. The linear regression and Bayesian methods recommended more accurate dosage regimens; however, they require additional resources such as information technology and healthcare personnel with background training in pharmacokinetics. The Bayesian methods offered additional advantages such as calculation of doses based on a single-serum concentration and optimisation of the patient's previous pharmacokinetic data to determine subsequent dosage regimens. Computerised programs, utilising the Bayesian estimation procedures, are able to achieve target concentrations in a greater percentage of patients earlier in the course of therapy than the empiric trough concentrations and population methods. We recommend the use of these programs providing there is appropriate expertise available to make appropriate recommendations.

Increases in Australian cutaneous abscess hospitalisations: 1999-2008.

Staphylococcus aureus is the most common cause of skin and soft tissue infections (SSTIs). Such infections have increased in several countries recently and at a time when community-associated methicillin-resistant S. aureus (CA-MRSA) strains have emerged globally. We examined changes in Australian hospitalisations for the treatment of cutaneous abscesses between 1999 and 2008, a period when increased numbers of CA-MRSA infections were being reported. National hospitalisation data for cutaneous abscess treatment (1999-2008) were examined. Hospitalisation numbers were collated and age-specific admission rates calculated and examined for changes over time. Yearly admissions for the treatment of cutaneous abscesses increased by 48%, from 8,849 (1999-2000) to 13,126 (2007-2008). The crude annual hospitalisation rate per 100,000 population rose from 46 to 62 respectively. However, increases in admission rates were limited to the 10 to 54 years age range. Incidence rate ratios (IRRs) for final versus baseline year admission rates for these age groups ranged from 1.36 (95% confidence interval [CI] 1.04-1.78) for those aged 10-14 years to 1.64 (95% CI 1.26-2.12) for those aged 45-49 years; p<0.05. Increases in hospitalisation for cutaneous abscess treatment have occurred in Australia during the last decade. Research into the underlying causes and prevention of these infections is a public health priority.

Influenza-associated bacterial pathogens in patients with 2009 influenza A (H1N1) infection: impact of community-associated methicillin-resistant Staphylococcus aureus in Queensland, Australia.

BACKGROUND: Secondary bacterial pneumonia due to community onset methicillin-resistant Staphylococcus aureus (MRSA) has become a highly publicised cause of influenza-associated death. There is a risk that case reports of fatal outcomes with post-influenza MRSA pneumonia may unduly influence antibiotic prescribing. AIMS: The aim of this study was to demonstrate the incidence of community-onset MRSA pneumonia in 2009 H1N1 influenza patients. METHODS: The microbiology records of patients positive for influenza A (H1N1) in 2009 were reviewed for positive blood or respiratory tract cultures and urinary pneumococcal antigen results within a Queensland database. Patients with such positive results within 48 h of hospital admission and a positive H1N1 influenza result in the prior 6 weeks were included. RESULTS: In 2009, 4491 laboratory-confirmed pandemic influenza A (H1N1) infections were detected. Fifty patients (1.1% of the H1N1 cohort) who were hospitalised with H1N1 and who had a bacterial respiratory tract pathogen were identified. Streptococcus pneumoniae (16 patients; 32%), Staphylococcus aureus (13 patients; 26%) and Haemophilus influenzae (9 patients; 18%) were the most commonly cultured organisms. Of the cohort of 4491 patients, MRSA was detected in only two patients, both of whom were admitted to intensive care units and survived after prolonged admissions. CONCLUSIONS: Influenza-associated community-onset MRSA pneumonia was infrequently identified in the 2009 H1N1 season in Queensland, despite community-onset MRSA skin and soft tissue infections being very common. Although post-influenza MRSA pneumonia is of great concern, its influence on empiric-prescribing guidelines should take into account its incidence relative to other secondary bacterial pathogens.

The gene encoding human glutathione synthetase (GSS) maps to the long arm of chromosome 20 at band 11.2.

Two forms of glutathione synthetase deficiency have been described. While one form is mild, causing hemolytic anemia, the other more severe form causes 5-oxo-prolinuria with secondary neurological involvement. Despite the existence of two deficiency phenotypes, Southern blots hybridized with a glutathione synthetase cDNA suggest that there is a single glutathione synthetase gene in the human genome. Analysis of somatic cell hybrids showed the human glutathione synthetase gene (GSS) to be located on chromosome 20, and this assignment has been refined to subband 20q11.2 using in situ hybridization.