Gianluca Ottria

Fungal Contamination in Hospital Environments

OBJECTIVES To assess the degree of fungal contamination in hospital environments and to evaluate the ability of air conditioning systems to reduce such contamination. METHODS We monitored airborne microbial concentrations in various environments in 10 hospitals equipped with air conditioning. Sampling was performed with a portable Surface Air System impactor with replicate organism detection and counting plates containing a fungus-selective medium. The total fungal concentration was determined 72-120 hours after sampling. The genera most involved in infection were identified by macroscopic and microscopic observation. RESULTS The mean concentration of airborne fungi in the set of environments examined was 19 +/- 19 colony-forming units (cfu) per cubic meter. Analysis of the fungal concentration in the different types of environments revealed different levels of contamination: the lowest mean values (12 +/- 14 cfu/m(3)) were recorded in operating theaters, and the highest (45 +/- 37 cfu/m(3)) were recorded in kitchens. Analyses revealed statistically significant differences between median values for the various environments. The fungal genus most commonly encountered was Penicillium, which, in kitchens, displayed the highest mean airborne concentration (8 +/- 2.4 cfu/m(3)). The percentage (35%) of Aspergillus documented in the wards was higher than that in any of the other environments monitored. CONCLUSIONS The fungal concentrations recorded in the present study are comparable to those recorded in other studies conducted in hospital environments and are considerably lower than those seen in other indoor environments that are not air conditioned. These findings demonstrate the effectiveness of air-handling systems in reducing fungal contamination.

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.

Spread of multidrug carbapenem-resistant Acinetobacter baumannii in different wards of an Italian hospital

BACKGROUND Multidrug-resistant Acinetobacter baumannii (MDRAB) is an important cause of hospital acquired infection. We describe a 7-month outbreak of a MDRAB infection involving various wards of an Italian hospital and an investigation of the possible source of the infection was conducted. METHODS A baumannii was isolated from various biological samples from 22 colonized or infected patients, and was identified and characterized for its antibiotic sensitivity. Typing of A baumannii was performed by multilocus sequence typing (MLST). Investigation of the outbreak involved extensive microbiological sampling of the environment. RESULTS In 50% of cases the infection occurred in the ICU. Invasive procedures were performed in 63.6% of patients. The strain isolated proved to be resistant to all the antibiotics tested, including carbapenems, and displayed the same allelic profile in all patients. None of the 141 samples taken during environmental monitoring showed positivity for A baumannii. CONCLUSION The results of the present study reveal the importance of strict adherence to control measures by all health care personnel and highlight the fact that regular staff training and frequent revision of control measures are essential to the successful management of an outbreak.

Multidrug-resistant Acinetobacter baumannii outbreak: an investigation of the possible routes of transmission

OBJECTIVES To establish the possible sources and routes of transmission of a multidrug-resistant Acinetobacter baumannii outbreak involving 22 patients. STUDY DESIGN Descriptive, retrospective study. METHODS An environmental investigation was undertaken, monitoring surfaces, air and water. Reconstruction of the spread of the infection took several factors into account such as intrahospital movements of patients and healthcare personnel, hospitalization of patients in the same ward and in chronologically compatible periods, and length of stay. A. baumannii clinical samples were typed using the Multilocus Sequence Typing scheme. RESULTS The outbreak originated from a patient admitted to the sub-intensive care unit, and the infection subsequently spread to other wards. The allelic profile proved to be the same for all the clinical isolates. Environmental monitoring yielded negative results for A. baumannii. CONCLUSIONS The results suggest that this epidemic spread through cross-transmission involving healthcare workers.

Chemical Characterisation of the Coarse and Fine Particulate Matter in the Environment of an Underground Railway System: Cytotoxic Effects and Oxidative Stress—A Preliminary Study

Background: Exposure to the particulate matter produced in underground railway systems is arousing increasing scientific interest because of its health effects. The aim of our study was to evaluate the airborne concentrations of PM10 and three sub-fractions of PM2.5 in an underground railway system environment in proximity to platforms and in underground commercial areas within the system, and to compare these with the outdoor airborne concentrations. We also evaluated the metal components, the cytotoxic properties of the various fractions of particulate matter (PM) and their capacity to induce oxidative stress. Method: We collected the coarse fraction (5–10 µm) and the fine fractions (1–2.5 µm; 0.5–1 µm; 0.25–0.5 µm). Chemical characterisation was determined by means of spectrometry. Cytotoxicity and oxidative stress were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and Reactive Oxygen Species (ROS) assessment. Results: The concentrations of both PM10 and PM2.5 proved to be similar at the three sampling sites. Iron and other transition metals displayed a greater concentration at the subway platform than at the other two sites. The 2.5–10 µm and 1–2.5 µm fractions of PM from all three sampling sites determined a greater increase in ROS; the intensity of oxidative stress progressively declined as particle diameter diminished. Moreover, ROS concentrations were correlated with the concentrations of some transition metals, namely Mn, Cr, Ti, Fe, Cu, Zn, Ni and Mo. All particulate matter fractions displayed lower or similar ROS values between platform level and the outdoor air. Conclusions: The present study revealed that the underground railway environment at platform level, although containing higher concentrations of some particularly reactive metallic species, did not display higher cytotoxicity and oxidative stress levels than the outdoor air.

Evaluation of contamination by blood aerosols produced during various healthcare procedures

This study aimed to quantify the blood content of aerosols produced during dental, maxillofacial and autopsy procedures and to identify those activities which involve the greatest risk of infection due to exposure to blood-containing aerosols. A total of 132 air samples were taken in several dental cubicles, a maxillofacial operating theatre and an autopsy room. The concentration of haemoglobin (Hb) in the samples was quantified and, for each day of sampling, the concentration of blood/m(3) of air aspirated (muL blood/m(3) air) was calculated. Hb was detected in 38.64% of samples. The mean concentration of Hb in the samples was 0.10+/-0.19 microg Hb/m(3) of aspirated air, with a range of 0-0.72 microg Hb/m(3). No statistically significant differences in the concentration of blood aerosol per m(3) of aspirated air were noted among the three types of activity analysed (P>0.05). Although there is, as yet, no concrete proof of the risk of infection through blood-containing aerosols, minimising the production and dispersal of aerosols and spatters is strongly recommended.

Epidemiology, management, and outcome of carbapenem-resistant Klebsiella pneumoniae bloodstream infections in hospitals within the same endemic metropolitan area

In the last decade, carbapenem-resistant Klebsiella pneumoniae (CR-Kp) has become endemic in several countries, including Italy. In the present study, we assessed the differences in epidemiology, management, and mortality of CR-Kp bloodstream infection (BSI) in the three main adult acute-care hospitals of the metropolitan area of Genoa, Italy. From January 2013 to December 2014, all patients with CR-Kp BSI were identified through the computerized microbiology laboratory databases of the three hospitals. The primary endpoints of the study were incidence and characteristics of CR-Kp BSI in hospitals within the same endemic metropolitan area. Secondary endpoints were characteristics of CR-Kp BSI in hospitals with and without internal infectious diseases consultants (IDCs) and 15-day mortality. During the study period, the incidence of healthcare-associated CR-Kp BSI in the entire study population was 1.35 episodes per 10,000 patient-days, with substantial differences between the three hospitals. Patients admitted to the two hospital with internal IDCs were more likely to receive post-susceptibility test combined therapy including carbapenems (77% vs. 26%, p<0.001), adequate post-susceptibility test therapies (86% vs. 52%, p<0.001), and post-susceptibility therapies prescribed by an infectious diseases specialist (84% vs. 14%, p<0.001). Overall, the crude 15-days mortality was 26%. In the final multivariable model, only septic shock at BSI presentation was unfavorably and independently associated with 15-days mortality (odds ratio [OR] 6.7, 95% confidence intervals [CI] 2.6-17.6, p<0.001), while a protective effect was observed for post-susceptibility test combined therapies including a carbapenem (OR 0.11, 95% CI 0.03-0.43, p=0.002). Mortality of CR-Kp remains high. Differences in the incidence of CR-Kp BSI were detected between acute-care centers within the same endemic metropolitan area. Efforts should be made to improve the collaboration and coordination between centers, to prevent further diffusion of CR-Kp.

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 μg/m3. 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.