Microbiological surveillance of endoscopes and implications for current reprocessing procedures adopted by an Italian teaching hospital.

BACKGROUND: Hospital acquired infections have been associated with the contamination of flexible endoscopes caused by a failure of the reprocessing procedure. Microbiological surveillance of endoscope reprocessing is valuable for assessing contamination by pathogens. The aim of this study is to evaluate microbiological contamination of endoscopes after reprocessing, and the involvement of reprocessing procedures adopted in endoscopy units of an Italian teaching-hospital. METHODS: The study was carried out, on several dates in 2014, in 11 endoscopic operation units equipped with 100 endoscopes (18 bronchoscopes, 41 gastroduodenoscopes, 29 colonoscopes, 12 laryngoscopes) and 9 Automated Endoscope Reprocessors. Presence/absence of common pathogens and indicator micro-organisms (including multi-drug resistant bacteria) and Total Microbiological Count (TMC) were obtained from the biopsy channels of endoscopes after reprocessing, from final rinse water of automated endoscope reprocessors and from tap water applying standard microbiological culture methods. Following the European Guidelines for quality assurance in reprocessing, the post-reprocessing criteria were "absence of indicator micro-organisms and absence of TMC in samples obtained from endoscopes' channels". RESULTS: A total of 180 samples were collected (143 endoscopes, 25 Automated Endoscope Reprocessors and 12 water supply). Compliance to the European Guidelines was achieved for 112 out of the 180 (62.2%) samples analyzed. Presence of indicator micro-organisms (mainly Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa and other Gram-negative non-fermenting bacteria) was found in 51 out of 143 endoscopes (35.7%). Multi-drug resistant bacteria were also found. Presence of pathogen micro-organisms was statistically associated with the increase of TMC level, but not with time after reprocessing. CONCLUSION: The study provides information about the microbiological quality of endoscope reprocessing procedures adopted by different endoscopic operation units. The high prevalence of contaminated endoscopes provides evidence of the need to improve the quality of reprocessing.

Human exposure to antibiotic resistant-Escherichia coli through irrigated lettuce.

Antibiotic resistant bacteria (ARB) have been found on fresh fruit and vegetables globally. These types of ARB infections are spreading rapidly and are a major human health threat. A quantitative human exposure assessment model was created using scenario analysis to investigate the potential human exposure to antibiotic resistant Escherichia coli (AR-E. coli) through the consumption of lettuce irrigated with surface water. Scientific literature and site specific data were collected to model each process from farm to fork to calculate the concentration of AR-E. coli on the lettuce at the point of human consumption. The processes examined were the adhesion, colonisation and viability of bacteria on the lettuce; the effect of different post-harvest cleaning processes; the effect of consuming the lettuce before, on or after the expiry date; and the effect of the consumer washing the lettuce. The results show the mean human exposure levels ranged between 1.00 × 10-2 and 1.35 × 106 colony forming units (CFU) of AR-E. coli per 100 g of surface water irrigated lettuce for the different scenarios investigated. The mean probability of illness from consuming 100 g of lettuce contaminated with potential pathogenic antibiotic-sensitive E. coli was between 1.46 × 10-9 to 1.88 × 10-2. A back calculation revealed that in order for the EC No 1441/2007 regulation to be exceeded (≥1000 CFU/g of E. coli on lettuce at the manufacturing stage), the mean contamination levels required in the irrigation water would need to be 2.7, 3.1 or 4.8 log CFU/ml using the post-harvest treatments of washing with water, rapid cooling with water and washing with a chlorine solution respectively. The information generated from this model could help to set guidelines for producers on maximum permissible AR-E. coli contamination levels in irrigation water and provides recommendations on the best post-harvest treatment to use.

Evaluation of timing of re-appearance of VBNC Legionella for risk assessment in hospital water distribution systems.

BACKGROUND: In this study we estimated the presence of Legionella species, viable but non-culturable (VBNC), in hospital water networks. We also evaluated the time and load of Legionella appearance in samples found negative using the standard culture method. METHODS: A total of 42 samples was obtained from the tap water of five hospital buildings. The samples were tested for Legionella by the standard culture method and were monitored for up to 12 months for the appearance of VBNC Legionella. RESULTS: All the 42 samples were negative at the time of collection. Seven of the 42 samples (17.0%) became positive for Legionella at different times of monitoring. The time to the appearance of VBNC Legionella was extremely variable, from 15 days to 9 months from sampling. The most frequent Legionella species observed were Legionella spp and L. anisa and only in one sample L. pneumophila srg.1. CONCLUSIONS: Our study confirms the presence of VBNC Legionella in samples resulting negative using the standard culture method and highlights the different time to its appearance that can occur several months after sampling. The results are important for risk assessment and risk management of engineered water systems.

[The scientific contributions by the Roman School of Hygiene on the microbiological quality of the surface waters of Rome and her County from 1890 to 2010. A systemic review]. / La produzione scientifica della Scuola Romana di Igiene sulla qualità microbiologica dei corpi idrici superficiali di Roma e Provincia dal 1890 al 2010. Una review sistematica.

Research on quality of surface waters has been performed also in Italy during the development of the large urban areas, and in Rome this has been the duty of the Istituto di Igiene of the Sapienza University since 1890. Using MedLine--and also traditional consultation for papers printed before 1968--we identified 100 articles printed in the period 1890-2010. Thirty of them met the inclusion criteria (to have been written by researchers belonging to the Rome universities and to contain microbiological informations about the surface waters of Rome). The majority of papers identified (46.6%) were produced during the years Sixties and Seventies of the 20th century, and 30% in the twenty years to follow (1980-1999). The most frequent microbiological descriptors were "Total coliforms" and "Streptococci". The waterbodies most investigated were the Tiber river and the coastal waters around Fiumicino, where the Tiber flows into the Tyrrhenian sea. The quality of surface waters has always been a central interest of the research performed by the Hygienists of the Roman School. The good quality of the past research and the renovated interest of International Organizations and of the European Union should encourage the public health researchers toward a strategic field of investigation which has strong interconnections with the protection of the individual and community health and also with the protection of the environment.