Patrizia Laurenti

Legionella Infection Risk from Domestic Hot Water

We investigated Legionella and Pseudomonas contamination of hot water in a cross-sectional multicentric survey in Italy. Chemical parameters (hardness, free chlorine, and trace elements) were determined. Legionella spp. were detected in 33 (22.6%) and Pseudomonas spp. in 56 (38.4%) of 146 samples. Some factors associated with Legionella contamination were heater type, tank distance and capacity, water plant age, and mineral content. Pseudomonas presence was influenced by water source, hardness, free chlorine, and temperature. Legionella contamination was associated with a centralized heater, distance from the heater point >10 m, and a water plant >10 years old. Furthermore, zinc levels of <20 μg/L and copper levels of >50 μg/L appeared to be protective against Legionella colonization. Legionella species and serogroups were differently distributed according to heater type, water temperature, and free chlorine, suggesting that Legionella strains may have a different sensibility and resistance to environmental factors and different ecologic niches.

Prospective 3-year surveillance for nosocomial and environmental Legionella pneumophila: implications for infection control.

OBJECTIVES To perform a 3-year, prospective surveillance program for legionnaires disease (LD) in a large university hospital in Rome, and to assess the usefulness of the hospital water monitoring program in predicting the risk of nosocomial LD. METHODS Samples from patients with new cases of nosocomial pneumonia were sent for legionella laboratory investigations. Meanwhile, water samples for bacteriological analysis were collected every 6 months from high- and medium-risk hospital wards (10 in total). Legionella pneumophila isolates collected were serotyped and analyzed by pulsed-field gel electrophoresis. RESULTS From June 2001 through May 2004, the pneumonia surveillance identified one case of nosocomial LD among 43 cases of nosocomial pneumonia (2.3%). Environmental investigations detected L. pneumophila in 12 (18.7%) of the 64 water samples, of which 50% belonged to serogroup 1. The L. pneumophila count and the percentage of positive locations never exceeded 10(2) colony-forming units/L and 20%, respectively, except when the LD nosocomial case occurred (positive water samples, 40%; L. pneumophila count, <10(2) colony-forming units/L). Genotyping showed 3 prevalent clones of L. pneumophila in the water distribution network, of which one persisted over the 3 years. One clone contained 3 different L. pneumophila serogroups (2, 4, and 6). CONCLUSIONS The low incidence of nosocomial cases of LD appears to be associated with a low percentage (<20%) of positive water samples per semester and with a low contamination level (<10(2) colony-forming units/L). An infection control system for nosocomial LD should, therefore, be based on both environmental and clinical surveillance, together with the appropriate maintenance of the hospital water distribution system.

A molecular typing approach for evaluating bioaerosol exposure in wastewater treatment plant workers

Bioaerosols associated with wastewater treatment process may represent a health risk for occupationally exposed personnel. To evaluate microbial contamination in plant workers, we compared oral cavity isolates against isolates collected from aerosol surrounding the aeration basin. Typing was performed by metabolic profile and arbitrarily primed-polymerase chain reaction. The latter is more sensitive and rapid than conventional tests. After comparison, isolates from the air samples were not related to those obtained from the exposed workers. This molecular approach can support bioaerosol risk evaluation .

Non-fermentative gram-negative bacteria in hospital tap water and water used for haemodialysis and bronchoscope flushing: Prevalence and distribution of antibiotic resistant strains

This study provides a detailed description of the distribution of non-fermentative gram-negative bacteria (NFGNB) collected in water sources (tap water and water used for haemodialysis and bronchoscope flushing) from different wards of a tertiary care hospital. The aim is to identify risk practices for patients or to alert clinicians to the possible contamination of environment and medical devices. The resistance profile of NFGNB environmental isolates has shown that more than half (55.56%) of the strains isolated were resistant to one or more antibiotics tested in different antimicrobial categories. In particular, 38.89% of these strains were multidrug resistant (MDR) and 16.67% were extensively drug resistant (XDR). The most prevalent bacterial species recovered in water samples were Pseudomonas aeruginosa, Pseudomonas fluorescens, Ralstonia pickettii and Stenotrophomonas maltophilia. Analysis of antibiotic resistance rates has shown remarkable differences between Pseudomonadaceae (P. aeruginosa and P. fluorescens) and emerging pathogens, such as S. maltophilia and R. pickettii. Multidrug resistance can be relatively common among nosocomial isolates of P. aeruginosa, which represent the large majority of clinical isolates; moreover, our findings highlight that the emergent antibiotic resistant opportunistic pathogens, such as R. pickettii and S. maltophilia, isolated from hospital environments could be potentially more dangerous than other more known waterborne pathogens, if not subjected to surveillance to direct the decontamination procedures.

Tuberculosis in Sheltered Homeless Population of Rome: An Integrated Model of Recruitment for Risk Management

The authors show the results of an integrated model for risk management of tuberculosis in a sample of sheltered homeless in Rome. Tuberculin skin test (TST) was used for evaluating the prevalence of latent infection (LTBI). In TST positives, expectorate was collected and chest X-ray was achieved. Multiple logistic regression analysis was performed to investigate determinants of infection. Out of 288 recruited subjects, 259 returned for the TST reading; 45.56% were positive and referred to a specialized center; 70 accessed the health facility and completed the clinical pathway. The risk factors associated to LTBI were male gender (OR = 3.72), age over 60 years (OR = 3.59), immigrant status (OR = 3.73), and obesity (OR = 2.19). This approach, based on an integrated social network, guarantees high adherence to screening (89.93%), allowing patients testing positive for latent tuberculosis infection to be diagnosed and rapidly referred to a specialized center.

Knowledge, experiences, and attitudes of medical students in Rome about tuberculosis

Background Tuberculosis is the second leading cause of death from infectious disease. Insufficient knowledge among doctors about tuberculosis is one of the reasons for the increased tuberculosis rates in several low-endemic countries. The purpose of this study was to assess knowledge, experience, and attitude about tuberculosis among medical students. Material/Methods After a pilot study, a cross-sectional survey was performed on fifth-year medical students at the Catholic University of Rome (Italy), using a self-administered questionnaire on attitude, experience and knowledge about epidemiology, diagnosis, and treatment of tuberculosis. The t test and multivariable linear regression analysis were performed to estimate the association between TB knowledge and investigated variables. Results Among 220 fifth-year medical students, the response rate was 83.1%. The mean percentage of correct answers was 56.6% (63.5% for epidemiology and prevention, 54.1% for diagnosis, and 45.7% for treatment). Associations between internships in wards and greater knowledge of tuberculosis diagnosis (55.9% vs. 51.6%, p=0.02), treatment (48.4% vs. 41.8%, p=0.03) and total score (58.1% vs. 54.5%, p=0.04) were found. Students who reported receiving the Mantoux test had higher knowledge of tuberculosis epidemiology and prevention (65.4% vs. 53.3%, p=0.001), diagnosis (55.2% vs. 48.3%, p=0.005), and total score (58.0% vs. 49.1%, p=0.001). Students who had observed at least 1 active pulmonary tuberculosis case had a higher percentage of correct answers about diagnosis (55.5% vs. 51.4%, p=0.03) and total score (57.9% vs. 54.0%, p=0.03). The multivariable linear regression confirmed the association between higher knowledge and receiving the Mantoux test (β coefficient=7.2; 95% CI 2.6–11.7), as well as having observed at least 1 X-ray of a TB patient (β coefficient=5.3; 95% CI 1.0–9.7). Conclusions A moderate level of general knowledge about tuberculosis was found, which suggests the need to modify current programs of infectious diseases in the curriculum of medical schools.

Legionella on board trains: effectiveness of environmental surveillance and decontamination

BackgroundLegionella pneumophila is increasingly recognised as a significant cause of sporadic and epidemic community-acquired and nosocomial pneumonia. Many studies describe the frequency and severity of Legionella spp. contamination in spa pools, natural pools, hotels and ships, but there is no study analysing the environmental monitoring of Legionella on board trains. The aims of the present study were to conduct periodic and precise environmental surveillance of Legionella spp. in water systems and water tanks that supply the toilet systems on trains, to assess the degree of contamination of such structures and to determine the effectiveness of decontamination.MethodsA comparative pre-post ecological study was conducted from September 2006 to January 2011. A total of 1,245 water samples were collected from plumbing and toilet water tanks on passenger trains. The prevalence proportion of all positive samples was calculated. The unpaired t-test was performed to evaluate statistically significant differences between the mean load values before and after the decontamination procedures; statistical significance was set at p ≤ 0.05.ResultsIn the pre-decontamination period, 58% of the water samples were positive for Legionella. Only Legionella pneumophila was identified: 55.84% were serogroup 1, 19.03% were serogroups 2–14 and 25.13% contained both serogroups. The mean bacterial load value was 2.14 × 103 CFU/L. During the post-decontamination period, 42.75% of water samples were positive for Legionella spp.; 98.76% were positive for Legionella pneumophila: 74.06% contained serogroup 1, 16.32% contained serogroups 2–14 and 9.62% contained both. The mean bacterial load in the post-decontamination period was 1.72 × 103 CFU/L. According to the t-test, there was a statistically significant decrease in total bacterial load until approximately one and a half year after beginning the decontamination programme (p = 0.0097).ConclusionsThis study indicates that systematic environmental surveillance could be a useful approach for assessing the risk of exposure to Legionella bacteria, which still represents a public health threat. According to the study results, an environmental surveillance programme, followed by decontamination procedures where necessary, would decrease the total bacterial count, protecting the health of travellers and workers.

Prevalence of cutipositivity in a sample of homeless shelter population in Rome in the course of Latent Tuberculosis Infection surveillance plan. Preliminary results

Background : in Europe homelessness is a known risk factor both for active and latent tuberculosis (TB). In Rome 409 cases of TB were notified in 2004, but the real occurrence among homeless people is unknown. Tuberculosis surveillance has been organized with the aim to develop an integrated model for the risk evaluation and management of both Latent Tuberculosis infections (LTBI) and TB in Rome homeless people. Methods : the eligible individuals have been recruited in the homeless’ refuges. The Tuberculin Mantoux test has been used to evaluate the infection prevalence; in case of a positive result, the individual’s expectorate has been collected and the chest X-ray has been performed. A collecting data form has been filled in for evaluating some risk factors. Multiple logistic regression models have been carried out to find statistically significant determinants of infection. Results : out of 120 subjects recruited, 108 came back for the evaluation of the skin test; the prevalence of LTBI was 43.5% (47/108 subjects); no active TB cases were found. According to the multivariate analysis, factors significantly associated to LTBI are gender (for males OR = 4.94; 95% CI: 1.46 – 16.67, 1st model; OR 5.84; 95% CI: 1.26 – 21.10, 2nd model), birth place (for Europe: OR 3.05; 95% CI: 1.02 – 9.13, 1st model; OR 3.12; 95% CI: 1.10 – 8.88, 2nd model; for East Mediterranean native Region OR = 4.34; 95%CI: 1.15-16.39); Body Mass Index class (for obesity OR = 3.34; 95% CI:1.31-8.51). Conclusions : these preliminary results have demonstrated a high prevalence of LTBI among homeless people. Male gender, birth place (Europe and East Mediterranean native Region) and obesity were found to be significant risk factors. The surveillance system allowed positive patients for LTBI to be rapidly directed to a specialized centre for the clinical evaluation and the appropriate therapy in order to prevent the evolution of disease.

Respiratory Diseases and Health Disorders Related to Indoor and Outdoor Air Pollution

Chronic respiratory diseases are the most important respiratory diseases and affect more than 500 million people. Even if they are likely to be underdiagnosed, it is estimated that asthma affects more than 230 million people, obstructive sleep apnea syndrome (OSAS) affects more than 100 million people, and more than 60 million people suffer from symptomatic chronic obstructive pulmonary disease (COPD). Asthma causes 250,000 deaths and COPD kills about three million people each year. Each chronic respiratory disease can have direct and indirect annual costs of many thousand dollars per patient. These costs are a huge burden on the budgets of the health systems of the richest countries and on the lives of the families living in the developing countries.

Enterobacteriaceae Antibiotic Resistance in Ready-to-Eat Foods Collected from Hospital and Community Canteens: Analysis of Prevalence

Foodborne diseases and antibiotic resistance are serious widespread health problems in the contemporary world. In this study, we compared the microbiological quality of ready-to-eat (RTE) foods found in community canteens versus hospital canteens in Rome, Italy, focusing on detection and quantification of Enterobacteriaceae and the antibiotic resistance of these bacteria. Our findings show a remarkable difference in Enterobacteriaceae contamination between RTE foods distributed in community canteens (33.5% of samples) and those distributed in hospital canteens (5.3% of samples). This result highlights greater attention to good manufacturing practices and good hygiene practices by the food operators in hospitals compared with food operators in community canteens. As expected, a higher percentage of cold food samples (70.9%) than of hot food samples (10.8%) were positive for these bacteria. Excluding the intrinsic resistance of each bacterial strain, 92.3% of the isolated strains were resistant to at least one antibiotic, and about half of the isolated strains were classified as multidrug resistant. The prevalence of multidrug-resistant strains was 50% in the community samples and 33.3% in hospital canteens. Our results indicate that approximately 38% of RTE foods provided in community canteens is not compliant with microbiological food safety criteria and could be a special risk for consumers through spread of antibiotic-resistant strains. Hygienic processing and handling of foods is necessary for both hospital and community canteens.