Experimental Studies on the Microbiota associated with Urinary Tract Infections

Urinary tract infections (UTIs) are one of the most common healthcare associated infections (HCAIs) accounting for 17.2% of the total HCAI’s in England. Some of the underlying issues associated with UTIs include recurrent infections, catheter associated UTIs and antibiotic resistance. These issues are responsible for prolonged hospital admissions, increased costs and significant morbidity. Another possible issue relates to the ubiquitous protozoa, Acanthamoeba. Although it is known to cause infections in humans, the amoeba has been isolated from apparently healthy people. Furthermore, Acanthamoeba is known to have an endosymbiotic relationship with bacteria. Therefore, it is reasonable to hypothesise that Acanthamoeba may possibly play an important role in UTIs. Clinical isolates of E. coli, K. pneumoniae and P. mirabilis were used in the current study. All uropathogens exhibited the ability to form biofilms in a nutrient dependent manner and complete the biofilm cycle within 24h. They also displayed the ability to form intracellular bacterial communities in urothelial cells and induce significant cytotoxicity. Moreover, they were able to associate, invade and survive within Acanthamoeba castellanii (T4). Furthermore, 200 urine samples from patients suspected of UTIs were collected from Colchester University Hospital NHS Trust and analysed for the presence of Acanthamoeba. Nineteen samples were positive for Acanthamoeba spp. (unclassified) and two samples for A. castellanii supporting our hypothesis that the amoeba possibly plays a role in UTIs. This is the first study in the UK to have confirmed the presence of Acanthamoeba in urine. This study also investigated the antimicrobial efficacy of cetylpyridinium chloride (CPC). CPC coated latex catheters were able to prevent biofilm formation at very low concentrations. This finding provides promising evidence for the potential application of CPC impregnated catheters in preventing CAUTIs. In conclusion, the findings from this study can be used to develop targeted interventions aimed at the underlying issues associated with UTIs.