Legionella colonization of water supply pipes is a significant public health problem. The objective of this work was to evaluate Legionella colonization in hotel hot water systems and to investigate the relationship between metal concentrations, piping materials (galvanized iron pipes and plastic pipes), and Legionella proliferation. Concentrations of calcium and magnesium ions and the presence of Legionella pneumophila were determined in a total of 108 water samples from the hot water systems of four hotels in Split-Dalmatia County over a 12-month period, and additional data on piping materials were collected. L. pneumophila was isolated in 23.1% of all samples—in 28.8% (15/52) of water samples from galvanized iron pipes and in 17.8% (10/56) of samples from plastic pipes. L. pneumophila serogroups 2–14 were isolated from all samples. This study found higher prevalence of L. pneumophila at higher concentrations of Ca and Mg ions (except for Mg and plastic pipes). The metal parts of the water supply may be important factors in Legionella contamination due to the possibility of lime scale or roughness of the pipes. Higher Ca and Mg ion concentrations increased the risk of Legionella colonization. View Full-Text
Posted in Contaminated water, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Legionella, Legionella anisa, Legionella rubilucens, Legionnaires’ disease, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research, Water, water microbiology, Water Safety
08 February 2022
In July 2021, the Legionella Control Association (LCA), in conjunction with the Health and Safety Executive (HSE), Public Health England (PHE) and local authorities, held a webinar aimed at raising awareness of increasing Legionella positivity rates post lockdown. The data demonstrated that the average positive rate in the UK had increased by around 2% following the lockdowns in response to COVID-19.
To investigate if there were particular species that could have led to this increase, LCA approached the three commercial laboratories in the UK that use MALDI-ToF to confirm down to species level, and asked if they would share their data. This information has now been returned by some laboratories, with findings from over 70,000 positive result samples in a two-year period revealing:
- over 53% of the results were L.anisa
- over 32% of the positives were L. pneumophilia, both SeroGroup 1 and SeroGroup 2-15
- nearly 1% of positives were for L. rubilucens
- over 6.5% of the results did not confirm a species type
- there were over a dozen other species identified in results that accounted for less than 1% of the data set
The first line clinical diagnostic tool used to confirm Legionnaire’s disease in the UK is commonly a urinary antigen test (UAT), and this method looks predominantly for L. pneumophilia SeroGroup 1. Given the data LCA has provided so far, this could potentially mean missing over 70% of Legionella infections in patients. It should be highlighted that this data is in its infancy, and LCA state that further research needs to take place before any significant changes are considered or undertaken.
Source: LCA, January 2022
Posted in Contaminated water, Cooling Towers, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, L. pneumophilia, Legionella, Legionella anisa, Legionella rubilucens, Legionnaires’ disease, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research, Water, water microbiology, Water Safety