Evaluation of Microbial Growth in Hospital Textiles Through Challenge Test.

INTRODUCTION: Ensuring the microbiological quality of textiles is an important requirement for health care facilities. The present study examines the way transport times and temperatures influence microbial growth in textiles. Therefore, the effectiveness of washing and disinfection processes has also been studied. METHODS: Microbial Challenge Tests were set up through the artificial contamination of different dry and wet textiles which were stored at different temperatures. The bacterial concentration was evaluated in well-defined time phases aimed at simulating the time it took for the textiles to be transported from the hospital facilities to the reconditioning unit. Three times were therefore considered from T = 0 inoculation moment to T = 72 h post inoculation. At the end of each time, the increase in bacterial concentration was assessed by means of microbiological cultures, using selective media for the enumeration of each type of inoculated microorganism. RESULTS: In all the contaminated textiles the bacterial concentration remained unchanged at a temperature of 4 °C, while at 22 °C and 37 °C there was a significant increase (p < 0.05) starting from 8 h of storage. In these textiles, the microorganism that showed the greatest growth capacity was P. aeruginosa with average initial concentration values of 104 CFU/cm2 and a final concentration of 1.5 × 105 CFU/cm2 at 22 °C and 1 × 105 CFU/cm2 at 37 °C 72 h after inoculum. CONCLUSION: The data highlights the fact that the degree of contamination in textiles does not undergo an increase when transport takes place at a controlled temperature. Refrigerated transport of hospital textiles is thus a desirable preventive measure to keep microbiological risk under control.

Ten-Year Retrospective Analysis of Legionella Diffusion in Hospital Water Systems and Its Serogroup Seasonal Variation.

INTRODUCTION: Legionella spp. are ubiquitous aquatic organisms found to be associated with community-acquired pneumoniae (CAP) as well as hospital-acquired pneumonia (HAP). Direct inhalation of aerosols from environmental colonisation is typically the source of infection. The aim of this study was to determine the level of colonisation in hospital water supply systems in order to assess the criticality of the water distribution network and strengthen preventive measures. METHODS: From 2009 to 2018, 769 water samples were collected and then analysed according to the standard methods indicated in ISO11731-2:2004 and ISO11731:2017 for Legionella detection. RESULTS: The samples were positive in 37.1% cases (n. 285) and negative in 62.9% cases (n. 484). The threshold of 10,000 CFU/L was exceeded in 15.1% cases and led to decolonisation as indicated by Italian and European ECDC guidelines. In the autumn-winter period SG1 showed a positivity of 41.2% (n. 40) with a decrease in the spring-summer period with 9.6% (n. 18) of positivity. In contrast, SG2-15 showed a positivity of 30.9% (n. 30) in autumn-winter, which tends to increase to 56.9% (n. 112) in spring-summer (p < 0.001). CONCLUSION: Surprisingly, besides showing a seasonal trend already described previously in the literature, the positivity of our sample was not balanced even for serogroups in the two periods. This could be due to genetic differences and ecological niches to be further investigated that could also have links with the greater pathogenicity of SG1. Environmental microbiological surveillance and risk assessment should be performed more frequently and disinfection must be carried out, especially in health facilities where people are more susceptible to infections.

Evaluation of growth potential and growth dynamics of Listeria monocytogenes on ready-to-eat fresh fruit.

The consumption of fresh or RTE fruits is increasing every year and Listeria monocytogenes has been identified on raw or minimally processed fruits. A food product can become contaminated with L. monocytogenes anywhere along the pathway of food production during planting, harvesting, packaging, distribution and serving. The aim of this work was to assess the microbiological risks associated with consumption of ready- to- eat fruit such as melon, pineapple, coconut and fruit salad. The presence of Escherichia coli, Salmonella spp. and L. monocytogenes was also evaluated. Microbiological challenge tests were carried out for the evaluation of the L. monocytogenes growth potential in RTE fruit stored at 4 and 8°C. E. coli counts resulted under the detection limit of 10 CFU g-1, Salmonella and L. monocytogenes were not detected (absence in 25g). The growth potential values in coconut and melon (δ>0.5) showed the growth capacity of Listeria at the temperatures considered. A low initial load, also derived from good hygiene practices, and correct storage temperatures are essential to reduce bacterial growth in RTE fruit. The challenge test showed how each type of RTE fruit has a different commercial life based on its specific growth potential and that food should be stored at temperatures not higher than 4°C for a short period.