Testing Isogenicity of Recurrent UTI in Postmenopausal Women
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PURPOSE: Due to increase in antibiotic allergies and resistance, the care of older women with recurrent urinary tract infections (UTIs) can be extremely challenging. Antibiotic regimens assume that infections are due to a single genetically identical species or isogen. The aim of this study was to use the classic method of phage typing to test whether the UTI pathogen in a patient is isogenic. Our hypothesis posits that infection may be due to the existence of a complex ecology of simultaneous infection by multiple same-species strains. METHODS: Mid-stream urine samples were taken from postmenopausal women with history of documented recurrent UTIs. Standard urine culture confirmed the presence of Escherichia coli bacterial strain. Urine sample was spread on LB agar plate and incubated for 24hrs at 37 degrees Celsius. 50 separate colonies were picked from the incubated plate and were treated in a patch assay with novel UTI targeting phages from the Rajagopal/Thomas Lab. Transilluminated images where taken with Biorad Image Lab equipment; then sensitivity to each phage was rated. Urine sample from patient 9 was used because our Lab had the most phages specific to lysing it. Phage clearings from the patch were rated on a scale of 0-3 based upon prevailing phage-typing metrics. (Ward et al. year) RESULTS: Differences to phage sensitivity across the 50 colonies numbered 9-1 to 9-50 were noted. Colonies 9-8, 9-44, and 9-46 were notably more resistant to a set of phages that was effective on all the other colonies. DISCUSSION: These findings in one representative older woman with recurrent UTI caused by Escherichia coli may have clinical significance particularly if differential phage sensitivity correlates with virulence, biofilm production, and antibiotic sensitivity variations. Pathogen findings in our urine samples suggest that infection may be an ecology of related, but nonidentical bacteria. CONCLUSION: The observed differences in phage sensitivity suggest there are multiple related, but non isogenic, Escherichia coli in the same bladder, a mechanism possibly contributing to antibiotic resistance and thus leading to UTI recurrence. Next step is to test each colony clone for its antibiotic sensitivity profile to determine if this novel observation could be clinically relevant.