Survival of animal and human-associated Listeria monocytogenes in drinking water and biofilms

Abstract

Land slugs are occasionally observed as contaminants in groundwater wells and drinking water treatment plants including storage tanks. Slugs may feed on carrion and feces, and they are potential vectors of pathogens such as Listeria monocytogenes. We isolated L. monocytogenes from the pest slug Arion vulgaris and examined persistence and survival of human and slug derived L. monocytogenes in groundwater-based drinking water and biofilms. L. monocytogenes survival was evaluated using cultivation and cultivation-independent techniques. L. monocytogenes remained culturable for 35–47 days in drinking water with first order decay rates between 0.314 and 0.457 h−1 (T99 ≥10 days). Attachment of L. monocytogenes to filter sand delayed washout from drinking water filters and increased persistence 2–3-fold. Indigenous biofilms stimulated initial surface attachment 10–100 fold but L. monocytogenes declined more rapidly in drinking water biofilms compared to virgin filters not colonized by microorganisms. Grazing by protozoa likely attenuated L. monocytogenes survival in some drinking water biofilms. A comparable survival pattern was observed for L. monocytogenes and the fecal indicator bacterium E. coli. The study suggests that live L. monocytogenes can persist for weeks as sessile organisms in groundwater-based drinking water supplies and may subsequently be released to the drinking water.

Occurrence of Multidrug-Resistant Listeria monocytogenes in Environmental Waters: A Menace of Environmental and Public Health Concern

“…Also, a previous study posited that the capability of Lm isolates for biofilm formation could be attributed to the level of expression of the prfA and agr genes (Gandra et al, 2019;Grudlewska-Buda et al, 2020). In addition, Lm ability for biofilm formation is known to enhance its persistence in the environment and also contribute to higher antimicrobial resistance (Pan et al, 2006;Grudlewska-Buda et al, 2020;Bjergbaek et al, 2021). Although, Herbert-Guillou et al (2001 put forward that biofilm is usually formed wherever there is water in the environment.…”