Paolo Orlando

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.

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.

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.

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.

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.

An overview of carbapenem-resistant Klebsiella pneumoniae: epidemiology and control measures

The emergence and dissemination of carbapenem resistance among Enterobacteriaceae, especially Klebsiella pneumoniae, constitute a serious threat to public health, since carbapenems are the agents of last resort in the treatment of life-threatening infections caused by drug-resistant Enterobacteriaceae. In K. pneumoniae, carbapenem resistance was first reported a decade ago and has subsequently emerged in several countries. One particular group of transmissible plasmid-encoded carbapenemase enzymes, designated K. pneumoniae carbapenemase (KPC), confers carbapenem resistance to K. pneumoniae strains and is rapidly spreading worldwide. In addition to KPC-producing K. pneumoniae, several different metallo-&bgr;-lactamase-producing strains have been identified. These include New Delhi metallo-&bgr;-lactamase, Verona integron-encoded metallo-&bgr;-lactamase and imipenemase metallo-&bgr;-lactamase. Finally, class D carbapenemases, including oxacillin-type carbapenemases, also occur in K. pneumoniae. Carbapenem-resistant K. pneumoniae (CRKP) can cause several types of healthcare-associated infections, including pneumonia, bloodstream infections, wound or surgical site infections, urinary tract infections and meningitis, and is associated with high mortality rates. Multifactorial intervention, including hand hygiene, contact precautions, patient and staff cohorting, minimizing invasive device use, promoting antimicrobial stewardship, screening, active surveillance testing and chlorhexidine bathing, may be an effective strategy for reducing the nosocomial transmission of CRKP. Moreover, the rapid notification of clinical infection whenever CRKP are identified from clinical specimens allows the timely implementation of control measures.

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.

The role of the environment in the spread of emerging pathogens in at-risk hospital wards

Infections in hospital high-risk environments due to emerging pathogens as Pseudomonas aeruginosa, Burkholderia cepacia, Stenotrophomonas maltophilia or heterogeneous glycopeptide-intermediate Staphylococcus aureus are responsible for a high mortality rate. The severity of these infections is due to bacterial virulence factors, their resistance to multiple antibiotics and the associated difficulty in treating infections. Although resistance to a single antimicrobial agent or class is troublesome, of greater concern is the development of resistance to multiple agents or classes, which severely limits treatment options. This is a major public health problem and a cause of substantial morbidity and mortality among hospitalized patients, especially in at-risk wards. The hospital environment can act as a reservoir of these microorganisms. The main reservoirs identified in hospital settings are water, medical devices that are not thoroughly cleaned/disinfected or dried, contaminated solutions, hands, colonized or infected patients, air and surfaces. To better prevent nosocomial infections related to emerging pathogens, the control of the hospital environment, the strict application of hand disinfection and other recommended procedures, and the investigation of potential cross-transmission in the hospital setting are needed.