Barriers to the implementation of antimicrobial stewardship programmes in long-term care facilities: a scoping review.

BACKGROUND: Long-term care facilities (LTCFs) present specific challenges for the implementation of antimicrobial stewardship (AMS) programmes. A growing body of literature is dedicated to AMS in LTCFs. OBJECTIVES: We aimed to summarize barriers to the implementation of full AMS programmes, i.e. a set of clinical practices, accompanied by recommended change strategies. METHODS: A scoping review was conducted through Ovid-MEDLINE, CINAHL, Embase and Cochrane Central. Studies addressing barriers to the implementation of full AMS programmes in LTCFs were included. Implementation barriers described in qualitative studies were identified and coded, and main themes were identified using a grounded theory approach. RESULTS: The electronic search revealed 3904 citations overall. Of these, 57 met the inclusion criteria. All selected studies were published after 2012, and the number of references per year progressively increased, reaching a peak in 2020. Thematic analysis of 13 qualitative studies identified three main themes: (A) LTCF organizational culture, comprising (A1) interprofessional tensions, (A2) education provided in silos, (A3) lack of motivation and (A4) resistance to change; (B) resources, comprising (B1) workload and staffing levels, (B2) diagnostics, (B3) information technology resources and (B4) funding; and (C) availability of and access to knowledge and skills, including (C1) surveillance data, (C2) infectious disease/AMS expertise and (C3) data analysis skills. CONCLUSIONS: Addressing inappropriate antibiotic prescribing in LTCFs through AMS programmes is an area of growing interest. Hopefully, this review could be helpful for intervention developers and implementers who want to build on the most recent evidence from the literature.

Confirmation of presumptive Legionella colonies on culture media according to ISO 11731:2017: principles, problems, and practice.

AIMS: The ISO 11731 norm, published in 2017, describes a method to identify and enumerate Legionella based exclusively on the confirmation of presumptive colonies by subculturing them on BCYE and BCYE-cys agar (BCYE agar without L-cysteine). METHODS AND RESULTS: Despite this recommendation, our laboratory has kept confirming all presumptive Legionella colonies by combining the subculture method with the latex agglutination and polymerase chain reaction (PCR) assays. Here, we show that the ISO 11731:2017 method adequately performs in our laboratory according to ISO 13843:2017. We compared the performance of the ISO method in detecting Legionella in typical and atypical colonies (n = 7156) from health care facilities (HCFs) water samples to that of our combined protocol, and we found a 2.1% false positive rate (FPR), underscoring the importance of combining agglutination test and PCR with subculture to achieve optimal confirmation. Lastly, we estimated the water system disinfection cost for HCFs (n = 7), which due to false positive results, would display Legionella values exceeding the threshold of risk acceptance established by the Italian guidelines. CONCLUSIONS: Overall, this large-scale study indicates that the ISO 11731:2017 confirmation method is error-prone, leading to significant FPRs, and higher costs for HCFs due to remedial actions on their water systems.

Hand hygiene monitoring: Comparison between app and paper forms for direct observation.

Healthcare-associated infections (HAIs) are a global public health threat. Italy is one of the countries with the highest prevalence of HAI. Hand hygiene (HH) is a pillar of infection prevention and control. Monitoring HH is necessary to improve HH compliance, and direct observation is considered the gold standard. Transcription and analysis of data collected during direct observation of HH compliance with the WHO paper form are time-consuming. We collected, during a 9-day observation period, HH opportunities and compliance both with a smartphone application (SpeedyAudit) and with the WHO paper form. Then, we investigated the difference in the required time for data transcription and analysis between the WHO paper form and the use of the app. The difference in the required time for data transcription and analysis was significant with a mean time of 2 s using the app and about 14-54 min/day using paper form (p = .004) while no significant difference was found in measured compliance rates between the two data collecting methods. HH monitoring with an app is time-saving, and the app we used was easy to use.

A cross-sectional study of SARS-CoV-2 seropositivity among healthcare workers and residents of long-term facilities in Italy, January 2021.

Long-term care facilities (LTCFs) are high-risk settings for SARS-CoV-2 infection. This study aimed to describe SARS-CoV-2 seropositivity among residents of LTCFs and health-care workers (HCWs). Subjects were recruited in January 2021 among unvaccinated HCWs of LTCFs and hospitals and residents of LTCFs in Northern Italy. Information concerning previous SARS-CoV-2 infections and a sample of peripheral blood were collected. Anti-S SARS-CoV-2 IgG antibodies were measured using the EUROIMMUN Anti-SARS-CoV-2 QuantiVac ELISA kit (EUROIMMUN Medizinische Labordiagnostika AG). For subjects with previous COVID-19 infection, gender, age, type of subject (HCW or resident), and time between last positive swab and blood draw were considered as possible determinants of two outcomes: the probability to obtain a positive serological result and antibody titer. Six hundred and fifty-eight subjects were enrolled. 56.1% of all subjects and 65% of residents presented positive results (overall median antibody titer: 31.0 RU/ml). Multivariable models identified a statistically significant 4% decrease in the estimated antibody level for each 30-day increase from the last positive swab. HCWs were associated with significant odds for seroreversion over time (OR: 0.926 for every 30 days, 95% CI: 0.860-0.998), contrary to residents (OR: 1.059, 95% CI: 0.919-1.22). Age and gender were not factors predicting seropositivity over time. Residents could have a higher probability of maintaining a seropositive status over time compared to HCWs.

Comparison of BCYEα+AB agar and MWY agar for detection and enumeration of Legionella spp. in hospital water samples.

BACKGROUND: This study illustrates for the first time the performance (sensitivity and selectivity) of the selective medium BCYEα +AB suggested by the new edition of ISO 11731 for legionella isolation and enumeration. We compared the efficacy of the selective BCYEα +AB medium with that of the highly selective MWY medium. RESULTS: Legionella spp. was detected in 48.2 and 47.1% of the samples by BCYEα +AB and MWY agar, respectively. For optimal detection of Legionella spp., most protocols recommend using selective media to reduce the number of non-Legionella bacteria. Agreement between the two media was 86.7%. CONCLUSIONS: According to the results, both media have a very similar performance and they both have advantages and disadvantages over each other. In AB medium there is the risk of being less selective so more interfering microbiota may grow but in MWY medium there is the risk of being too selective. The low selectivity of the AB medium could be resolved if other treatments are applied after filtration, e.g. acid and/or heat treatment, but it must be taken into account that these treatments still reduce the number of viable Legionella. In conclusion, we recommend using MWY as a selective medium for the detection of Legionella spp. as it is easier discern suspected colonies and facilitate the final Legionella spp.

Real-time PCR, the best approaches for rapid testing for Mycobacterium chimaera detection in heater cooler units and extracorporeal membrane oxygenation.

According to recent investigations, the risk of M. chimaera contamination of heater-cooler units (HCUs) has reached global proportions. Our aim was to field evaluate a protocol for early detection of M. chimaera contamination. We assessed the presence of viable M. chimaera in 395 water samples obtained from 48 devices (HCUs and extracorporeal membrane oxygenation) by Real Time PCR. Thirty devices were NTM positive, of which 14 were contaminated with M. chimaera. The most frequently contaminated devices were the Stockert 3T. Noteworthy, Stockert 3T devices were positive for M. chimaera. In conclusion, this study introduces novel PMA-PCR designed to specifically detect M. chimaera in HCUs and ECMO devices; this method can replace the culture method for continuous microbiological surveillance. The timely detection of M. chimaera contamination can then be used to improve effective management of the devices.

[Epidemiology and surveillance of hepatitis E in Italy: data from the SEIEVA surveillance system 2007-2019]. / Epidemiologia e sorveglianza dell'epatite E in Italia: dati dalla sorveglianza SEIEVA 2007-2019.

BACKGROUND: hepatitis E is a disease spread all over the world, with endemic levels varying according to ecological and socioeconomic factors. In developing countries, large epidemics spread mainly through contaminated water; in developed countries, hepatitis E has always been considered a sporadic disease, closely associated to the travels to endemic areas, especially in Southeastern Asia. In the last years, this perception is significantly changing, because of an increasing number of autochthonous cases reported in many European countries. OBJECTIVES: to describe the epidemiological picture of hepatitis E in Italy from 2007 to 2019. DESIGN: descriptive study based on the cases reported to the special surveillance of acute viral hepatitis (SEIEVA); case-control analytical study for the analysis of risk factors associated with hepatitis E. SETTING AND PARTICIPANTS: hepatitis E cases reported to SEIEVA in the period 2007-2019. MAIN OUTCOME MEASURES: number of cases notified by year, percentages of cases exposed to known risk factors, odds ratios. RESULTS: from January 2007 to June 2019, 385 hepatitis E cases were notified to SEIEVA. The annual number increased from 12 in 2007 to 49 in 2018, the increasing trend continued in 2019, when 39 cases were observed in the first 6 months of the year. Northern and Central Regions reported most of the cases; only a few were diagnosed in Southern Regions. Based on SEIEVA data, the trend of hepatitis E notifications has increased according to the increasing propensity to the differentiated diagnosis, at least until 2018. However, only 46% of suspected cases are tested to detect the presence of anti-HEV IgM antibodies, during the observation period; the percentage of tested cases is significantly lower in the South than in Northern and Central Italy (p<0.001). The reported cases have a median age of 48 years (range: 5-87) and are mostly males (80%); 32% was observed in foreign citizens mainly from endemic areas of South Asia (Bangladesh, India, and Pakistan). In 72.5% of cases, the infection was contracted in Italy. The most frequent risk factor is the consumption of raw or undercooked pork meat, especially sausages (70% of cases), significantly associated with hepatitis E risk (OR 3.0; IC95% 1.4-6.1). Other important risk factors are wild boar sausages consumption (40% of cases, OR 4.6, not statistically significant), and travels to endemic areas during the six weeks before the disease (31% of cases, OR 3.2; IC95% 1.6-6.4). CONCLUSIONS: hepatitis E can now be considered as endemic even in industrialized countries. In Italy, from 2007 an increasing number of cases has been reported. However, the real impact of HEV infection is still underestimated due to the limited number of clinical centres which perform tests for the search of anti-HEV IgM antibodies in cases of acute hepatitis. An ad hoc surveillance has been activated in January 2019 in some Local Health Units/Regions and extended to a national level starting from January 2020. This initiative is necessary in order to better dimension the burden of the disease associated with HEV infection, to study its epidemiology, and to increase awareness of this infection among health professionals.

Colonization by Pseudomonas aeruginosa of dental unit waterlines and its relationship with other bacteria: suggestions for microbiological monitoring.

Pseudomonas aeruginosa is an environmental bacterium, ubiquitous in aquatic habitats and water distribution systems, including dental unit waterlines (DUWLs). We investigated the prevalence of P. aeruginosa in DUWLs from private dental settings. We also analyzed the relationship between P. aeruginosa contamination and the presence of Legionella spp. and total viable count (TVC) in order to suggest a simple and inexpensive protocol to test the quality of water from DUWLs. We detected and quantified P. aeruginosa both by culture and by a PMA (propidium monoazide)-qPCR method. Overall, we detected P. aeruginosa in 17 samples using the PMA-qPCR and in 11 samples using the culture. All culture-positive samples were positive with the PMA-qPCR too, with an agreement between the two methods of 93% and a Cohen's kappa coefficient of κ = 0.747 (good concordance). Comparing results with results of our previous study, we noted that (a) P. aeruginosa was isolated only from DUWLs with high TVC and (b) five out of six Legionella-positive samples were negative for Pseudomonas spp. Our final suggestion is that the cleanliness of DUWLs should be assessed by TVC because it is a good indicator of the presence of pathogens such as Legionella spp. and P. aeruginosa.

[Good practices for the surveillance and control of antimicrobial resistance]. / Buone pratiche per la sorveglianza e il controllo dell'antibiotico-resistenza.

Italy is one of the European Countries with the highest level of antimicrobial consumption, both in the community and in hospital settings, and with the highest prevalence of antimicrobial resistant microorganisms. In 2015, the Project "Good practices for the surveillance and control of antimicrobial resistance" was funded by the Italian National Centre for Disease Prevention and Control (CCM): the aim was to promote integrated actions at national level to control antimicrobial resistance, favouring the transfer of existing good practices. The principal objectives of the project were: to describe the Italian scenario of good practices based on literature review; to improve the capacity of surveillance, through achieving consensus on a core set of indicators, including paediatrics, and through the strengthening of the national surveillance system of antimicrobial resistance coordinated by the Italian National Institute of Health; to define tools useful for priority setting; to evaluate the efficacy of intervention programme aimed at promoting the appropriate use of antibiotics among children for upper respiratory tract infections in the community; to set up training programmes on the prudent use of antibiotics in veterinary medicine. Seven regions were enrolled in the project (Emilia-Romagna with the role of programme coordinator, Campania, Calabria, Lazio, Lombardy, Piedmont, Tuscany) and the Italian National Health Institute. The project allowed to document: the scarce spread of control practices at national level (out of 277 studies reviewed, only 6.1% of the cases were targeted to evaluating the effectiveness of intervention programmes); a significant variability among regions both in relation to antimicrobial consumption and antimicrobial resistance prevalence, with a worrying spread in some regions of several antimicrobial resistant organisms responsible for "critical" infections with great potential health impact; the effectiveness of an intervention aimed at promoting appropriate use of antibiotics in frequent infections for children in the community, such as pharingotonsillitis and acute otitis media (35% reduction of antimicrobial consumption between 2010 and 2017 in Emilia-Romagna; an inversion of the ratio amoxicillin/amoxicillin-clavulanate); the need for new indicators to monitor antimicrobial consumption in hospital paediatric wards and of a new national system for timely identification of new antimicrobial resistance profiles; a positive evaluation of the training programme for veterinary physicians. In conclusion, the project has contributed to identify the most critical areas for antimicrobial resistance control and to select appropriate solutions, potentially transferable to the national level.

The role of chemical products at low doses in preventing the proliferation of bacteria in dental unit waterlines: the ICX® experience.

In this study we evaluated (1) the efficacy of a protocol that combines hydrogen peroxide (shock treatment) and ICX® tablets (continuous treatment) for the control of microbial contamination in dental unit water lines, and (2) the in vitro antimicrobial activity of ICX® tablets on collection and wild strains isolated from dental chair output waters. To assess the treatment effectiveness, the microbial load in the output water samples of three dental chairs were investigated: one control chair received only shock treatment. In vitro bactericidal activity was tested against Staphylococcus aureus and Pseudomonas aeruginosa. Data obtained from samples collected from chairs treated with ICX® and shock treatment and data from the control chair did not differ significantly on the basis of microbial load. In the in vitro study, the product was unable to kill Gram-negative bacteria. These results show that the continuous introduction of ICX® was not effective in maintaining low counts of the heterotrophic bacteria in the output water of dental devices, and shock treatment may be needed more frequently than monthly.

Ugly but tasty: A systematic review of possible human and animal health risks related to entomophagy.

BACKGROUND: According to many recent studies, the use of insects as food seems to be convenient, sustainable, economical and healthy. The objective of this study is to analyze the possible effects of insect consumption on human and animal health. METHODS: A systematic review of the literature was performed using the PubMed, Scopus and CAB databases. RESULTS: Of the 6026 items initially retrieved, 70 were eligible for inclusion; 40 studies analyzed the use of insects in human foods or drugs, while 30 analyzed the use of insects in animal feed. In humans, the most commonly analyzed risks are nutrient malabsorption, growth alteration, chemical and microbiological contamination and allergy risk. Studies of animals focus on growth alteration, nutrient malabsorption and hematic and qualitative meat alteration. CONCLUSION: In recent years, researchers have shifted their focus from the possible use of edible insects in animal feed to their use as possible nutrient sources for humans. The results suggest that, if properly treated and preserved, products derived from insects are safe and efficient sources of nutrients for animals. Further studies are needed to evaluate the possible effects of prolonged insect consumption on human health.

Delivery of written and verbal information on healthcare-associated infections to patients: opinions and attitudes of a sample of healthcare workers.

BACKGROUND: Patients education is considered a valuable mean to prevent and control healthcare-associated infections (HAIs). This cross-sectional study aims to assess declared practices of healthcare workers (HCWs) regarding the delivery of information about HAIs to patients. METHODS: A 14-item multiple-choice questionnaire was designed to assess the attitudes and declared practices of HCWs (physicians, nurses and nursing assistants). Between October 2012 and October 2013, we surveyed a sample of HCWs from 4 acute hospitals in Piedmont (North-western Italy). Written information was available at three hospitals (A, B and C) and verbal information at the last one (hospital D). RESULTS: We surveyed 288 HCWs (79 physicians, 124 nurses and 85 healthcare assistants). At hospital A, B and C, 128 (71.6%) HCWs declared that written information was usually delivered to any patient and 145 (66.5%) that nurses usually delivered it. Only 42 (26.3%) of them - 97.6% nurses -declared that they usually delivered written information to patients. Among all surveyed HCWs, 210 (72.9%) declared that patients also receive verbal information on HAI - mainly by nurses (70.8%) and physicians (50%) - but only 88 (29,2%) - 23.8% physician and 48.8% nurses - declared that they usually informed patients. Finally, 83 (27.7%) HCWs believed that they should decide whether or not to deliver information to patient case by case. CONCLUSIONS: A formal policy requiring to deliver written information is most likely not enough to induce HCWs to better inform patients about HAIs. Health Trusts might introduce more target actions to reinforce HCWs' practices, such as training and internal auditing.

The no correlation argument: can the morality of conscientious objection be empirically supported? the Italian case.

BACKGROUND: The legitimacy of conscientious objection to abortion continues to fuel heated debate in Italy. In two recent decisions, the European Committee for Social Rights underlined that conscientious objection places safe, legal, and accessible care and services out of reach for most Italian women and that the measures that Italy has adopted to guarantee free access to abortion services are inadequate. Nevertheless, the Ministry of Health states that current Italian legislation, if appropriately applied, accommodates both the right to conscientious objection and the right to voluntary abortion. MAIN BODY: One empirical argument used to demonstrate that conscientious objection does not create barriers to abortion is the "no correlation" argument, which the Italian Committee for Bioethics employed to demonstrate that no association exists between conscientious objection and waiting times for voluntary abortion in Italy and to support the weak form of conventional comprise adopted by the Italian legislation to balance the conflict between women' autonomy and healthcare professionals' moral integrity. Conversely, we showed how the "no correlation" argument fails to demonstrate the absence of a relationship between the number of conscientious objectors and waiting times for voluntary abortion, and that the limitations of the "no correlation" argument itself demonstrate how it is still difficult to describe the real effect of conscientious objection on the access to abortion services and to evaluate the suitability of conventional compromise to effectively balance conflicting moral principles. CONCLUSION: Further studies are needed to better describe the relationship between conscientious objection and waiting times for voluntary abortion. If new evidence would show that the increasing proportion of objectors does undermine the efficacy of the Italian law and the right of a woman to freely obtain a voluntary abortion, new ways will need to be found to address the conflict between moral principles and restrict the protection accorded to the principle of moral integrity. This would inevitably imply the need to constrain and to redefine the terms and conditions for claiming conscientious objection.

Viability-qPCR for detecting Legionella: Comparison of two assays based on different amplicon lengths.

Two different real-time quantitative PCR (PMA-qPCR) assays were applied for quantification of Legionella spp. by targeting a long amplicon (approx 400 bp) of 16S rRNA gene and a short amplicon (approx. 100 bp) of 5S rRNA gene. Purified DNA extracts from pure cultures of Legionella spp. and from environmental water samples were quantified. Application of the two assays to quantify Legionella in artificially contaminated water achieved that both assays were able to detect Legionella over a linear range of 10 to 10(5) cells ml(-1). A statistical analysis of the standard curves showed that both assays were linear with a good correlation coefficient (R(2) = 0.99) between the Ct and the copy number. Amplification with the reference assay was the most effective for detecting low copy numbers (1 bacterium per PCR mixture). Using selective quantification of viable Legionella by the PMA-qPCR method we obtained a greater inhibition of the amplification of the 400-bp 16S gene fragment (Δlog(10) = 3.74 ± 0.39 log(10) GU ml(-1)). A complete inhibition of the PCR signal was obtained when heat-killed cells in a concentration below 1 × 10(5) cells ml(-1) were pretreated with PMA. Analysing short amplicon sizes led to only 2.08 log reductions in the Legionella dead-cell signal. When we tested environmental water samples, the two qPCR assays were in good agreement according to the kappa index (0.741). Applying qPCR combined with PMA treatment, we also obtained a good agreement (kappa index 0.615). The comparison of quantitative results shows that both assays yielded the same quantification sensitivity (mean log = 4.59 vs mean log = 4.31).

Legionella in water samples: how can you interpret the results obtained by quantitative PCR?

Evaluation of the potential risk associated with Legionella has traditionally been determined from culture-based methods. Quantitative polymerase chain reaction (qPCR) is an alternative tool that offers rapid, sensitive and specific detection of Legionella in environmental water samples. In this study we compare the results obtained by conventional qPCR (iQ-Check™ Quanti Legionella spp.; Bio-Rad) and by culture method on artificial samples prepared in Page's saline by addiction of Legionella pneumophila serogroup 1 (ATCC 33152) and we analyse the selective quantification of viable Legionella cells by the qPCR-PMA method. The amount of Legionella DNA (GU) determined by qPCR was 28-fold higher than the load detected by culture (CFU). Applying the qPCR combined with PMA treatment we obtained a reduction of 98.5% of the qPCR signal from dead cells. We observed a dissimilarity in the ability of PMA to suppress the PCR signal in samples with different amounts of bacteria: the effective elimination of detection signals by PMA depended on the concentration of GU and increasing amounts of cells resulted in higher values of reduction. Using the results from this study we created an algorithm to facilitate the interpretation of viable cell level estimation with qPCR-PMA.

Appropriate use of antimicrobial prophylaxis: an observational study in 21 surgical wards.

BACKGROUND: Surveillance of Surgical Site Infections (SSI) in 2010 found 39 % compliance with hospital guidelines in Piedmont (Italy). The aim of the study was to estimate the appropriate use of antimicrobial prophylaxis and compliance with hospitals guidelines in surgical wards. METHODS: This survey study took place in 21 surgery wards of 4 public hospitals. Forms were completed by public health resident doctors together with a medical ward referent and infection control nurses. 15 consecutive surgical procedures were randomly chosen from each ward. A total of 320 cases were analyzed. The study period was from July 2012 to January 2013. Data were collected using a survey form. A final score variable from 0 to 4 was given to each case. The results were compared with hospital and international guidelines. Data were analyzed using Epi-Info software. RESULTS: Of the 320 cases collected, 63 were excluded; of the remaining 257 cases, 56.4 % of the procedures were appropriate (score 4), 15.2 % were acceptable and 28.4 % were not acceptable. The study found an unjustified continuation of antimicrobial prophylaxis in 17.1 % of the 257 cases, an unjustified re-start of antimicrobial therapy in 9.7 % and a re-dosing omission in 7.8 %. CONCLUSIONS: The study demonstrated critical problems in antimicrobial prophylaxis management in surgical wards due to a lack of compliance between hospitals and national guidelines, a shortage of specific and updated recommendations for some surgical interventions and incorrect local specific procedures. Coordination between local and national recommendations, strengthening of evidence based decisions and continuous sharing of policy updates are needed.

Conscientious objection and waiting time for voluntary abortion in Italy.

OBJECTIVES: This study sought to determine whether a correlation exists in Italy between conscience-based refusal by physicians to perform an abortion and waiting times for elective abortion. METHODS: Data on the number of objectors and of elective abortions performed within different time intervals were retrieved from annual Italian ministerial reports. Spearman's correlation coefficients were calculated between an indicator of the increase in workload for non-objectors when conscientious objection is exercised by physicians refusing to provide an abortion and the proportion of women whose request for an abortion was met within 14 days, or later, in 13 regions in Italy. RESULTS: An inverse correlation emerged between the workload for non-objectors and the proportion of abortions performed within 14 days of the request in seven regions (statistically significant in Emilia-Romagna and Tuscany). There was a direct correlation between increased workload and the proportion of abortions performed later than 21 days in nine regions. The same trends were highlighted at national level. CONCLUSIONS: Our results suggest that when data spanning at least more than a decade are available, a trend toward an inverse correlation can be noted between the workloads for non-objectors and timely access to elective abortion. This holds organisational and ethical implications.

Virulence of Legionella pneumophila strains isolated from hospital water system and healthcare-associated Legionnaires' disease in Northern Italy between 2004 and 2009.

BACKGROUND: Worldwide, L. pneumophila sg 1 is the most common agent of Legionnaires' disease ( 80 to 90% of the reported cases). In contrast, L. pneumophila sg 2-14 account for only 15 to 20% of community-acquired cases, although they account for over 50% of the environmental isolates. The discrepancy between environmental isolates and clinical cases of disease suggested that there are differences in virulence.We decided to subtype the environmental Legionella strains isolated from health care facilities (HCFs) and to compare the distribution of strains with the occurrence of hospital-acquired legionellosis. METHODS: Observational ecological study based on the data provided by the regional surveillance of legionellosis and on data obtained from hospitals environmental monitoring.Using the monoclonal antibody MAb 3/1 of the Dresden Panel we collected and typed environmental strains of L. pneumophila sg 1 obtained during routine testing in 56 health care facilities from 2004 to 2009.The results of the laboratory analyses of the environmental samples were compared with the number of cases that each health care facility reported during the study period. RESULTS: The association between the type of colonisation (L. pneumophila sg 1 vs others serogroups) and the incidence of reported cases was statistically significant (p = 0.03 according to the χ2 test).Legionella strains with the virulence-associated epitope recognised by MAb 3/1 were isolated in 8 of the 26 HCFs colonised by L. pneumophila sg 1; 7 of the HCFs colonised by MAb 3/1-positive strains accounted for 85% of the cases of hospital-acquired legionellosis reported during the 6-year study period. There was a statistically significant association (p = 0.003) between the presence of cases and colonisation by MAb 3/1-positive Legionella strains. CONCLUSION: This study suggests that hospitals colonised by more virulent strains should be aware of the increased risk and consider the opportunities of increase their monitoring efforts and implement more effective contamination control strategies.