Anna Maria Spagnolo

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.

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.

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.

Serological and molecular identification of Legionella spp. isolated from water and surrounding air samples in Italian healthcare facilities

BACKGROUND Legionella is an intracellular microorganism living in natural and artificial aquatic environments. Although its transmission to humans is linked to the inhalation of contaminated aerosols, there is no validated air sampling method for the control and prevention of the disease. The aim of the present study was to provide more information on the distribution of Legionella spp. in indoor environments and to determine whether the same Legionella strains are isolated from air and water samples. METHODS Ten healthcare facilities located in seven regions of Italy were enrolled. The serological typing of Legionella spp. from water samples and the surrounding air by active and passive sampling was assessed using polyvalent and monovalent antisera. Subsequently, the strains identified as Legionella pneumophila (Lpn) underwent molecular typing by sequence-based typing (SBT) using seven genes (flaA, pilE, asd, mip, mompS, proA, and neuA). The allelic profile number was assigned using the European Working Group for Legionella Infections-SBT database. RESULTS Lpn serogroup 6 was the most prevalent serogroup; it was found simultaneously in the air and water samples of three different healthcare facilities. In the remaining seven hospitals, Lpn serogroups 1, 6, 7, 9, and 12 were isolated exclusively from water samples. The molecular investigation showed that Lpn strains in the water and air samples of each positive healthcare facility had the same allelic profile. Strains, identified as sequence types (STs) 728 and ST 1638+ST 1324, were isolated in two respective healthcare facilities, and a new strain, identified as ST 1989, was obtained in one healthcare facility. CONCLUSION The application of the SBT method allowed to verify the homology among Legionella strains from water samples and the surrounding air. The results showed that the same Lpn strains were present in the air and water samples, and a new Legionella strain was identified.

Evaluation of Legionella Air Contamination in Healthcare Facilities by Different Sampling Methods: An Italian Multicenter Study

Healthcare facilities (HF) represent an at-risk environment for legionellosis transmission occurring after inhalation of contaminated aerosols. In general, the control of water is preferred to that of air because, to date, there are no standardized sampling protocols. Legionella air contamination was investigated in the bathrooms of 11 HF by active sampling (Surface Air System and Coriolis®μ) and passive sampling using settling plates. During the 8-hour sampling, hot tap water was sampled three times. All air samples were evaluated using culture-based methods, whereas liquid samples collected using the Coriolis®μ were also analyzed by real-time PCR. Legionella presence in the air and water was then compared by sequence-based typing (SBT) methods. Air contamination was found in four HF (36.4%) by at least one of the culturable methods. The culturable investigation by Coriolis®μ did not yield Legionella in any enrolled HF. However, molecular investigation using Coriolis®μ resulted in eight HF testing positive for Legionella in the air. Comparison of Legionella air and water contamination indicated that Legionella water concentration could be predictive of its presence in the air. Furthermore, a molecular study of 12 L. pneumophila strains confirmed a match between the Legionella strains from air and water samples by SBT for three out of four HF that tested positive for Legionella by at least one of the culturable methods. Overall, our study shows that Legionella air detection cannot replace water sampling because the absence of microorganisms from the air does not necessarily represent their absence from water; nevertheless, air sampling may provide useful information for risk assessment. The liquid impingement technique appears to have the greatest capacity for collecting airborne Legionella if combined with molecular investigations.

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.

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.