Fernanda Perdelli

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.

The impact of aerators on water contamination by emerging gram-negative opportunists in at-risk hospital departments

OBJECTIVE Our aim was to evaluate the impact of aerators on water microbiological contamination in at-risk hospital departments, with a view to quantifying the possible risk of patient exposure to waterborne microorganisms. DESIGN We analyzed the microbiological and chemical-physical characteristics of hot and cold water in some critical hospital departments. SETTING Two hospitals in northern Italy. METHODS We took 304 water samples over a 1-year period, at 3-month intervals, from taps used by healthcare personnel for handwashing, surgical washing, and the washing of medical equipment. We analyzed heterotrophic plate counts (HPCs) at 36°C and 22°C, nonfastidious gram-negative bacteria (GNB-NE), and Legionella pneumophila. RESULTS The percentages of positivity and mean values of HPCs at 22°C, HPCs at 36°C, and GNB-NE loads were significantly higher at outlet points than in the plumbing system. In particular, GNB-NE positivity was higher at outlet points than in the plumbing system in both the cold water (31.58% vs 6.58% of samples were positive) and hot water (21.05% vs 3.95%) supplies. Our results also revealed contamination by L. pneumophila both in the plumbing system and at outlet points, with percentages of positive samples varying according to the serogroup examined (serogroups 1 and 2-14). The mean concentrations displayed statistically significant (P < .001) differences between the outlet points (27,382.89 ± 42,245.33 colony-forming units [cfu]/L) and the plumbing system (19,461.84 ± 29,982.11 cfu/L). CONCLUSIONS These results reveal a high level of contamination of aerators by various species of gram-negative opportunists that are potentially very dangerous for immunocompromised patients and, therefore, the need to improve the management of these devices.

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.

Factors affecting individual exposure to NO2 in Genoa (northern Italy).

The individual exposure to nitrogen dioxide (NO2) of 89 volunteers living in Genoa, a large port city of northern Italy, was investigated with personal passive diffusion tubes in February-March 2000. The data were related to NO2 concentration in the kitchen and bedroom as measured by static samplers. Volunteers included students, workers and housewives living in three areas of Genoa differing by street traffic and industrial plant location. The kitchen samples showed higher (47.00+/-16.5 microg/m3) NO2 concentrations than those from the bedroom (24.78+/-9.8 microg/m3); overall indoor NO2 concentrations were lower in the Eastern area of Genoa, where outdoor pollution is lower. Students were the volunteer group with the lowest exposure rate (24.9+/-7.8 microg/m3 vs. 44.3+/-10.1 microg/m3 for workers and 40.0+/-13.4 microg/m3 for housewives). This difference is related to the fact that students spend more time indoors, where pollution levels are lower. The main household characteristics which were shown to affect personal NO2 exposure were (a) the presence of a chimney equipped with an active aspiration device in the kitchen and (b) the heating system.

Legionella pneumophila in healthcare facilities

Legionella pneumophila are gram-negative bacteria found in freshwater environments; they can survive as intracellular parasites of free-living protozoa and within biofilms in building water systems. L. pneumophila multiply at temperatures between 25 and 42°C, with an optimal growth temperature of 35°C. There are 16 serogroups of L. pneumophila. In Europe, approximately 70% of Legionella infections are caused by L. pneumophila serogroup 1 and 20–30% by other serogroups. These bacteria cause respiratory disease (legionellosis) in humans when a susceptible host inhales aerosolized water containing the bacteria or aspirates water containing the bacteria. Legionellosis classically presents as two distinct clinical entities: Legionnaires’ disease, a severe multisystem disease involving pneumonia, and Pontiac fever, a self-limited flu-like illness. Urine antigen tests and cultures of sputum or bronchoalveolar lavage are the most suitable clinical laboratory tests for Legionella. The new macrolide antibiotics, such as clarithromycin and azithromycin, show more effective in-vitro activity and a better intracellular and tissue penetration than erythromycin, as do the quinolones. Hospitals represent ideal locations for Legionnaires’ disease transmission: at-risk individuals are present in large numbers; plumbing systems are frequently old and complex, favouring multiplication of the organism; and water temperatures are often reduced to prevent scalding of patients. Safe water is vital to ensure patient safety and reduce costs where waterborne infections cause increasing morbidity, mortality, treatment costs, longer hospital stays and compensation claims. The WHO has developed Water Safety Plans for preventing or controlling the risks through system assessment, monitoring, surveillance and management/communication, so that health outcomes can be improved, that is a systematic approach is required to secure microbial safety.

Environmental and personal monitoring of exposure to urban noise and community response

Noise exposure of a population sample living in a city in northern Italy (Genoa) was assessed by measuring the noise in the area as well as with personal sound detectors. Sampling was conducted during a standard day and covered a period of time spent out-of-doors, at work (service sector) and at home. Ambient noise at home and at work was assessed with sound-level meters, personal exposure levels were assessed with personal sound-level/dosimeters. Information regarding each environment was obtained with an interview including also a subjective judgement on traffic intensity and noise levels. The mean individual equivalent continuous sound level (Leq) of recorded noise was 74.5 dB(A) for 24 h and 63.9 dB(A) at night. A further distinction was made between noise exposure at home (Leq 74.4), work (Leq 74.0) and during city transfers (Leq 79.3). Leq values for individual hours, Leq daytime (Leq, d), Leq nighttime (Leq, n) and Leq day-night (Ldn) indices calculated in the different environments, i.e. at work, home and out-of-doors, are reported here. Individual noise levels have then been compared with environmental data and with subjective noise exposure judgement.

Long-term decline of radiocesium concentration in seafood from the Ligurian Sea (Northern Italy) after Chernobyl

The activity of 137Cs, 134Cs and 40K in tissues from fish, molluse and shellfish of the Ligurian sea was measured during 1987-1988. The mean annual concentrations in 1987 were 5.92 +/- 4.1 Bq/kg (wet tissue) for 137Cs and 2.7 +/- 1.5 Bq/kg for 134Cs and 2.46 +/- 1.82 and 0.33 +/- 0.57 Bq/kg respectively in 1988. The mean value of 40K activity was 138.6 +/- 22.1 Bq/kg. Contamination was significantly higher in the littoral area up to 1000 m from the coast (8.39 +/- 7.6 and 1.74 +/- 2.08 Bq/kg respectively versus 2.91 +/- 1.87 and 0.58 +/- 0.59 Bq/kg respectively in the open sea). The common octopus (Octopus vulgaris) had the highest radioactivity values and could be utilized as an indicator of radioactivity pollution. There were no significant differences regarding the trophic level, the seafood phylum, or the east and west Ligurian sea areas. Long-term reduction in the sea habitat was estimated at about 200 days for 137Cs and 110 days for 134Cs, reflecting differences in the physical half-life of these radionuclides. These values were lower than those found in terrestrial foodstuff and could have reflected dilution of the contaminants in the open sea. The effective dose equivalent for the Ligurian population of radiocesium originating from seafood was estimated at 1.3 microSv in 1987 and 0.5 microSv in 1988. These va ues represent 0.8 and 0.3% respectively of the annual dose (180 microSv/year) due to 40K intake with the diet.

Increased Blood Lead Levels in Runners Training in Urban Areas

In an attempt to examine the hypothesis of whether physical activity causes increased uptake of lead in humans, blood lead levels were measured in 231 individuals. Included in the study were subjects who lived in Northern Italy and who practiced noncompetitive running in urban areas or along the countryside. The mean values (1.25 +/- 0.27 mumol/l) measured in a group of 28 runners who trained at tracks and on roads of a large town, characterized by heavy traffic and high atmospheric lead levels, were slightly higher than those recorded in a group of 10 runners of the same town who trained mostly in a rural environment (0.99 +/- 0.29 mumol/l) and, with a striking and significant difference, in a comparable group of 182 nonrunners (0.46 +/- 0.22 mumol/l). These background figures were similar to those found in 11 runners who lived in a smaller, less polluted urban area who trained in country roads (0.40 +/- 0.11 mumol/l). Blood lead levels were correlated significantly with the intensity and frequency of the running practice and were unrelated to smoking habits.

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.