Reduction in the incidence of MRSA with use of alcohol-based hand rub solutions and gloves.

Methicillin-resistant Staphylococcus aureus (MRSA) is highly contagious. It is spread by direct contact with MRSA-infected people or objects. Healthcare workers' hands are the most common vehicle for the transmission of healthcare-associated pathogens from patient to patient and within the healthcare environment. The present study aimed to investigate the correlation between the incidence of MRSA among Staphylococcus aureus recovered from clinical culture and the use of alcohol-based hand rub solutions or gloves and antimicrobial use density (AUD). All data were examined every 6 months between January 2005 and June 2008. The increasing use of alcohol-based hand rub solutions was correlated with a decreasing incidence of recovery of MRSA from clinical cultures (r(2) = 0.58). A statistically significant (P < 0.05) correlation (r(2) = 0.68) was observed between glove use and the incidence of MRSA. On the other hand, we did not find any correlation between the AUD of each antibiotic group and the incidence of MRSA. Thus, we suggest that it is important to use not only alcohol-based hand rubs, but also gloves, because MRSA is transmitted from patient to patient by the hands of healthcare workers.

Safety analysis of liposomal amphotericin B in adult patients: anaemia, thrombocytopenia, nephrotoxicity, hepatotoxicity and hypokalaemia.

Liposomal amphotericin B (L-AmB), which was developed to reduce side effects, has been shown to have a better safety profile than both the deoxycholate and lipid complex forms of amphotericin B; however, the frequency of major side effects is still unclear. Thus, the aim of the present study was to assess retrospectively the frequency of L-AmB-induced anaemia, thrombocytopenia, nephrotoxicity, hepatotoxicity and hypokalaemia as well as the relationship between daily dose of L-AmB and these side effects. A low red blood cell (RBC) count (post-/pre-treatment) and anaemia were observed in 7 and 10 of 21 adult patients, respectively. Thrombocytopenia was observed in 11 of 19 adult patients. Doses of L-AmB that are estimated to cause side effects of a low RBC count, anaemia and thrombocytopenia with 50% probability are 4.0, 3.3 and 3.0mg/kg/day, respectively. Nephrotoxicity was observed in 6 of 22 patients. Variations of total bilirubin, γ-glutamyl transpeptidase, aspartate aminotransferase and alanine aminotransferase used as indices of hepatotoxicity were observed in 6, 7, 8 and 8 of 22 patients, respectively. Hypokalaemia was observed in 4 of 9 patients; however, nephrotoxicity, hepatotoxicity and hypokalaemia were not caused in a dose-dependent manner. In conclusion, the present analyses showed that L-AmB dose-dependently induced anaemia and thrombocytopenia in adult patients. It is important to pay attention to causing anaemia and thrombocytopenia when patients are receiving L-AmB at doses of >3.3mg/kg/day and >3.0mg/kg/day, respectively.

An initial dosing method for teicoplanin based on the area under the serum concentration time curve required for MRSA eradication.

Teicoplanin is a glycopeptide antibacterial agent that has a long serum half-life and therefore takes time to achieve steady-state conditions. An appropriate initial dosing is needed for teicoplanin to promptly reach an effective serum trough concentration. However, little information is available on tailoring the initial dosing for patients with various characteristics. The objective of this study was to develop a nomogram for determining teicoplanin initial dose to promptly reach an effective trough concentration (≥ 13 µg/mL). A logistic regression analysis was performed to test whether the area under the concentration time curve (AUC) is a significant predictor of microbiological response (persistence 0; eradication 1). The study included 24 adult patients with methicillin-resistant Staphylococcus aureus infections [minimal inhibitory concentration (MIC) for the isolates was <2 µg/mL). Each AUC was estimated using individual dose, creatinine clearance (CL(cr)), and body weight data. The target value, which gives about a 0.9 microbiological eradication probability, was 750 µg h/mL for AUC from zero to 24 h (AUC(0-24 h)). Using published population pharmacokinetic parameters, the dose required to achieve the AUC(0-24 h) target was calculated as dose (mg) = 750 × (0.00498 × CL(cr) (mL/min) + 0.00426 × body weight (kg). For various combinations of CL(cr) and body weight, we checked the calculated doses using a therapeutic drug monitoring (TDM)-supporting software and developed a nomogram. The nomogram would be useful for initial dose adjustment to promptly reach an effective serum trough concentration and avoid adverse events of teicoplanin.

Higher linezolid exposure and higher frequency of thrombocytopenia in patients with renal dysfunction.

The major adverse event associated with linezolid treatment is reversible myelosuppression, mostly thrombocytopenia. Recent studies have reported that the incidence of linezolid-induced thrombocytopenia was higher in patients with renal failure than in patients with normal renal function, although the underlying mechanisms of this toxicity are still unknown. The present study thus aimed to investigate the relationship between renal function and linezolid exposure as well as the effects of drug exposure on thrombocytopenia. A statistically significant (P<0.01) strong correlation (r=0.933) was observed between linezolid clearance and creatinine clearance. A negative correlation (r=-0.567) was also shown between linezolid clearance and blood urea nitrogen, although the correlation was not statistically significant. In thrombocytopenic patients, the trough concentration was 14.4-35.6 mg/L and the area under the plasma linezolid concentration-time curve for 24h (AUC(24h)) was 513.1-994.6 mg h/L; in non-thrombocytopenic patients, drug exposure was relatively low (6.9 mg/L and 7.2mg/L for trough concentration and 294.3 mg h/L and 323.6 mg h/L for AUC(24h)). These results provide a pharmacokinetic explanation for the mechanism of the adverse event that renal dysfunction increased linezolid trough concentration and AUC and that higher drug exposure induced thrombocytopenia.

Determination of teicoplanin trough concentration target and appropriate total dose during the first 3 days: a retrospective study in patients with MRSA infections.

An initial loading procedure has been recommended to enable teicoplanin to promptly reach an effective serum concentration for the treatment of methicillin-resistant Staphylococcus aureus (MRSA). This study aimed to retrospectively evaluate the pharmacokinetics and pharmacodynamics of teicoplanin to determine the therapeutic target for the teicoplanin trough concentration and an appropriate dosing method during the first 3 days. The mean trough concentrations were 13.2 mg/L for patients with eradication of MRSA. Moreover, logistic regression analysis showed that the teicoplanin trough concentration was 13 mg/L to achieve MRSA eradication with a probability of 89.0%. The rates of achieving >or=13 mg/L in or=36 mg/kg (total dose during the first 3 days) groups were 9.1, 48.4 and 87.5%, respectively. These results suggest that the administration of >or=36 mg/kg during the first 3 days is appropriate to promptly obtain a trough concentration target of >or=13 mg/L for the initial treatment of MRSA infections.

Correlation between meropenem and doripenem use density and the incidence of carbapenem-resistant Pseudomonas aeruginosa.

Optimal use of carbapenems is an important issue in the prevention of resistance in Pseudomonas aeruginosa. In this study, we investigated the correlation between antimicrobial use density (AUD) of carbapenems and imipenem/cilastatin (IPM/CS) or meropenem (MEPM) susceptibility of P. aeruginosa strains. The AUD of five carbapenems [IPM/CS, panipenem/betamipron, biapenem, MEPM and doripenem (DRPM)] was examined every 6 months between 2006 and 2008. The AUD was calculated using the defined daily doses methodology developed by the World Health Organisation. A minimum inhibitory concentration of IPM/CS or MEPM of < or =4 mg/L was considered to be sensitive. There was a significant negative correlation between MEPM susceptibility and the total AUD of MEPM and DRPM [r=-0.823, 95% confidence interval (CI) -0.035 to -0.980; P=0.044]. Furthermore, there was a significant correlation between MEPM susceptibility and IPM/CS susceptibility (r=0.839, 95% CI 0.084 to 0.981; P=0.037). Cross-resistance was therefore investigated and only 5.6% of MEPM-insensitive strains were susceptible to IPM/CS, although 43.3% of IPM/CS-insensitive strains were susceptible to MEPM. These results suggest that curtailing the use of MEPM and DRPM may curb the emergence not only of MEPM-resistant strains but also IPM/CS-resistant strains.