Competitive colonization of Legionella and Pseudomonas aeruginosa in water systems of residential facilities hosting closed communities Legionella versus Pseudomonas aeruginosa in water systems of residential facilities.

Legionella and Pseudomonas aeruginosa are pathogens that live and multiply in water systems and resist disinfection through biofilm formation. As suggested by some studies, we wanted to verify whether the presence of P. aeruginosa can lead to a less frequent presence of Legionella in water systems of retirement homes and group homes. We collected 123 hot water and biofilm samples from showerheads. Samples were tested by selective culture methods, and Heterotrophic Plate Counts were determined. Legionella and P. aeruginosa were found in 35% and 39% of distal points, respectively. The presence of P. aeruginosa was significantly inversely correlated with the presence of Legionella when considering both matrices together (p<0.01), water samples only (p=0.02), and biofilm samples only (p=0.04). The inverse relationship was strong for L. pneumophila sg1 (Odds Ratio 0.182, p=0.002), while it is no longer verified when only L. pneumophila serogroups 2-14 are considered. The implications for the development of environmental investigations and risk management are discussed.

Taking Screenshots of the Invisible: A Study on Bacterial Contamination of Mobile Phones from University Students of Healthcare Professions in Rome, Italy.

Mobile phones (MPs) are commonly used both in the personal and professional life. We assessed microbiological contamination of MPs from 108 students in healthcare professions (HPs), in relation to their demographic characteristics and MPs handling habits, collected by means of a questionnaire. Cultural and biochemical tests were performed, and statistical analyses were carried out. Staphylococci were present in 85% of MPs, Enterococci in 37%, Coliforms in 6.5%; E. coli was never detected. Staphylococcus epidermidis was the most frequently isolated staphylococcal species (72% of MPs), followed by S. capitis (14%), S. saprophyticus, S. warneri, S. xylosus (6%), and by S. aureus (4%). Heterotrophic Plate Counts (HPC) at 37 °C, ranged from 0 to 1.2 × 104 CFU/dm2 (mean = 362 CFU/dm2). In univariate analysis, the male gender only was significantly associated with higher HPCs and enterococcal contamination. Multiple linear regression models explained only 17% and 16% of the HPC 37 °C and staphylococcal load variability, respectively. Developing specific guidelines for a hygienic use of MPs in clinical settings, for preventing cross-infection risks, is advisable, as well as introducing specific training programs to HP students. MPs decontamination procedures could also be implemented in the community.

Data on Legionella prevalence and water quality in showers of retirement homes and group homes in the Province of Rome, Lazio Region, Italy.

The data presented in this article are related to the research paper titled "Prevalence of Legionella in retirement homes and group homes water distribution systems" (De Filippis, 2018) [3]. Most of the cases of Legionella infection are sporadic and occur in community-dwellers. Hot water and biofilm samples from the showerheads of 26 retirement homes and 9 group homes hosting closed communities were collected, in order to evaluate the prevalence of Legionella and generic water quality parameters (Heterotrophic Plate Counts at 22 °C and 37 °C). Samples were tested by culture method for the presence of Legionella. Confirmation and identification were carried out through Latex test and PCR. Further data about buildings' number of floors and rooms were collected, and put in relation to the presence of Legionella through constructing contingency tables and performing exact fisher׳s or Chi-square tests. Cold (< 30 °C) water samples are analyzed apart.

Prevalence of Legionella in retirement homes and group homes water distribution systems.

BACKGROUND: Although historically the focus has been placed above all on hospital infections and travel-associated outbreaks, most of the cases of Legionella infection are sporadic and occur in community-dwellers. OBJECTIVES: To evaluate the presence and load of Legionella in hot water systems of non-healthcare facilities that host closed communities. Furthermore, we tried to verify the association between Heterotrophic Plate Counts (HPCs) and presence of Legionella. METHODS: We collected hot water and biofilm samples from the showerheads of retirement homes and group homes. Samples were tested by culture method for the presence of Legionella. Confirmation and identification were carried out through Latex test and PCR. We determined the HPCs at 22 and 37 °C by the pour plate method. Statistics performed through STATA. RESULTS: We collected 140 hot water and biofilm samples, 95 from 26 retirement homes and 35 from 9 group homes. Legionella was found in 36.8% samples collected from retirement homes and only in 10.3% group homes' samples (p = 0.01). Legionella was identified more frequently in water than in biofilm (29.8% vs 16.9%); just in one case the pathogen was found in the biofilm only. L. pneumophila sg 1 was the pathogen more frequently isolated (65.8%), with an average load of 2720 CFU/L (SD = 8393 CFU/L). We have often noticed a high microbial contamination (67% of HPCs >200 CFU/mL) and identified a higher prevalence of Legionella for intermediate values of HPC 22 °C (p = 0.011). 32% of people hosted in retirement homes were exposed to Legionella. CONCLUSIONS: Colonization of water-systems of retirement homes and group homes is anything but occasional, and in our survey it mainly affects the former, moreover often due to L. pneumophila sg 1. The search for the pathogen in the biofilm has proved to be of little use. The relationship between HPC and Legionella deserves further studies.

Occurrence of Legionella in showers at recreational facilities.

Critical environments, including water systems in recreational settings, represent an important source of Legionella pneumophila infection in humans. In order to assess the potential risk for legionellosis, we analyzed Legionella contamination of water distribution systems in 36 recreational facilities equipped with swimming pools. One hundred and sixty water samples were analyzed from shower heads or taps located in locker rooms or in bathrooms. By culture method and polymerase chain reaction, 41/160 samples were positive for Legionella from 12/36 recreational centers. Hotels (57.1%) and sports centers (41.2%) were the most contaminated. L. pneumophila serotypes 2-14 (25/41) were more frequently found than serotype 1 (10/41). Samples at temperature ≥30 °C were more frequently positive than samples at temperature <30 °C (n = 39 vs n = 2, p < 0.00001). The presence of L. pneumophila was investigated by comparison with heterotrophic plate count (HPC), an indicator of water quality. The presence of L. pneumophila was associated more frequently with high and intermediate HPC load at 37 °C, therefore should be considered a potential source when HPC at 37 °C is >10 CFU/mL. Maintenance, good hygiene practices, interventions on the hydraulic system and regular controls must be implemented to minimize exposure to L. pneumophila infection risk.