A new microbiological problem in intensive care units: environmental contamination by MRSA with reduced susceptibility to glycopeptides.

The present study evaluated the percentage of methicillin-resistant Staphylococcus aureus strains with reduced susceptibility to glycopeptides in four intensive care units (ICU) by means of environmental sampling of air and representative surfaces. The total bacterial count was taken and possible S. aureus strains were subsequently isolated. To assess methicillin resistance, an antibiogram was performed on the colonies that were positive to the coagulase test. A standard E-test was then carried out on the colonies that developed, in order to evaluate glycopeptide resistance, and any heterogeneous resistance was confirmed by means of a macromethod E-test. The antibiogram performed on the colonies of S. aureus revealed that 85.7% of all air samples were positive for MRSA, and that 64.3% of all the samples proved to be heterogeneously resistant to glycopeptides. Methicillin resistance was recorded in 41.0% of surface samples, and 32.5% of all samples proved positive for hGISA.

A problem of hospital hygiene: the presence of aspergilli in hospital wards with different air-conditioning features.

A total of 1,030 microbiological samples were taken in 3 hospital wards with different air-conditioning features: no conditioning system (ward A), a conditioning system equipped with minimum efficiency reporting value (MERV) filters (ward B), and a conditioning system thoroughly maintained and equipped with high-efficiency particulate air (HEPA) filters (absolute) (ward C). The air in each ward was sampled, and the bacterial and fungal concentrations were determined by active and passive methods. The concentration of fungi on surfaces was also determined. Active sampling showed positive samples in wards A and B only, with average values of 0.50 colony-forming units (CFU)/m(3) (95% CI, 0.30 to 0.70) in A and 0.16 CFU/m(3) (95% CI, 0.13 to 0.20) in B. Passive sampling was positive only in ward A (mean, 0.14 CFU/cm(2)/h; 95% CI, 0.13 to 0.15). Aspergillus was found in 27% and 22% of sampled surfaces in wards A and B, respectively, but in no samples from ward C. The most commonly found species was A. fumigatus (76% of cases in A and 34% of cases in B). The results show that the use of air-conditioning systems markedly reduces the concentration of aspergilli in the environment. Proper maintenance of these systems is clearly fundamental if their efficacy is to be ensured.

Evaluation of environmental contamination by glutaraldehyde in an outpatient facility for digestive endoscopy in an Italian hospital.

The potential harmful effects of glutaraldehyde on human health are well known, and in recent years various new substitutes for this compound have been proposed for the disinfection and thorough sterilization of medical instruments. Nevertheless, glutaraldehyde is still widely used in hospital environments. In order to evaluate environmental contamination by glutaraldehyde vapours, the rooms of a hospital out-patient department of digestive endoscopy were monitored in 2005; a total of 52 samples were taken. The mean environmental concentration of glutaraldehyde was 3.7+/-7.4 microg/m(3). The number of efficacious air exchanges per hour was 6.3 v/h in all of the environments monitored. The study revealed that, in a hospital setting, adequate structural and functional planning, combined with responsible management on the part of the personnel and constant careful checking of the results obtained can minimize the risk of occupational exposure to glutaraldehyde.

Evaluation of the risk of infection through exposure to aerosols and spatters in dentistry.

BACKGROUND: Many dental procedures produce extensive aerosols and splatters that are routinely contaminated with microorganisms. METHODS: Air containing blood-bearing aerosols and surfaces contaminated by sedimenting blood particulate was sampled in 5 different dental cubicles. To assess contamination by blood particulate, the concentration of hemoglobin (Hb) in the air and on the sedimentation surfaces was determined. RESULTS: The mean concentration of Hb in the air aspirated in the 5 cubicles was 0.14 +/- 0.23 microg/m(3), corresponding to a blood volume of 8.7 x 10(-4) microL/m(3). Similarly, the mean concentration of blood particulate sedimented on surfaces was calculated and found to be 1.56 microL/m(2). In 80% of the cubicles monitored, 100% positivity to the Hb determination test was recorded in all of the surface samples. CONCLUSIONS: The results obtained revealed contamination of both air and surfaces by blood particulate. Moreover, with the exception of those obtained in 1 cubicle, all of the samples of sedimenting particulate analyzed were positive for the presence of Hb.