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Urinary tract infections (UTI) are among the most frequently encountered infections in clinical practice globally. Predominantly a burden among female adults and infants, UTIs primarily caused by uropathogenic Escherichia coli (UPEC) results in high morbidity and fiscal health strains. During pathogenesis, colonization of the urinary tract via fimbrial adhesion to mucosal cells is the most critical point in infection and has been linked to DNA methylation. Furthermore, with continuous exposure to antibiotics as the standard therapeutic strategy, UPEC has evolved to become highly adaptable in circumventing the effect of antimicrobial agents and host defenses. Hence, the need for alternative treatment strategies arises. Since differential DNA methylation is observed as a critical precursor to virulence in various pathogenic bacteria, this body of work sought to assess the influence of the DNA adenine methylase (dam) gene on gene expression and cellular adhesion in UPEC and its potential as a therapeutic target. To monitor the influence of dam on attachment and FQ resistance, selected UPEC dam mutants created via one-step allelic exchange were transformed with cloned qnrA and dam complement plasmid for comparative analysis of growth rate, antimicrobial susceptibility, biofilm formation, gene expression, and mammalian cell attachment. The absence of DNA methylation among dam mutants was apparent. Varying deficiencies in cell growth, antimicrobial resistance and biofilm formation, alongside low-level increases in gene expression (recA and papI), and adherence to HEK-293 and HTB-9 mammalian cells were also detected as a factor of SOS induction to result in increased mutability. Phenotypic characteristics of parental strains were restored in dam complement strains. Dam’s vital role in DNA methylation and gene expression in local UPEC isolates was confirmed. Similarly to dam-deficient Enterohemorrhagic E. coli (EHEC), these findings suggest unsuccessful therapeutic use of Dam inhibitors against UPEC or dam-deficient UPEC strains as attenuated live vaccines. However, further investigations are necessary to determine the post-transcriptional influence of dam on the regulatory network of virulence genes central to pathogenesis.

Quinolone resistance is generally caused by chromosomal mutations, but has been more recently found associated with the plasmid-mediated qnr genes. The objective of this study was to screen and analyse polymorphisms of integrons in clinical isolates of Escherichia coli in Jamaica. Previous studies in Jamaica identified fluoroquinolone resistance in predominantly uropathogenic E. coli clinical isolates: 45% harbouring qnrA, qnrB and/or qnrS, and 17% were (Extended-spectrum beta-lactamase) ESBL-producers. These isolates were analysed for the presence and variation of class 1 and 2 integrase genes, 5'- and 3'- conserved segments and the Orf513 recombinase gene by primer-specific polymerase chain reaction (PCR) and restriction fragment-length polymorphism (RFLP). Results indicated integron-encoded integrases in 93% of isolates primarily harbouring class 1 integrase genes; four of 58 isolates carried both classes. The Orf513 and 5'- and 3'-conserved segment (CS) regions were identified in 83% and 55% of the isolates respectively. RFLP evaluation of the 5'- and 3'-CS regions in int1-positive strains yielded two main types. The reduced diversity, but wide dispersion of class 1 integrons harbouring qnr genes may give rise to the conservation of the mobile genetic elements in which they are carried.

Results: The epidemic-curve showed a propagating pattern, with most cases being detected during or subsequent to ICU admission. Cases had longer mean hospital (27.8 days vs 11.9 days) and ICU stays (31.0 days vs 7.3 days) than controls. The crude in-hospital mortality of cases was significantly higher than controls (OR 13.02; 95% CI: 2.98 -56.76). The final model showed co-morbid disease (Charlson Score) (AOR 1.68; 95% CI: 1.21 -2.33); mechanical ventilation (AOR 1.35; 95% CI: 1.02 -1.16) and receipt of piperacillin-tazobactam (AOR 1.33; 95% CI: 1.11 -1.61) to be significant predictors for invasive disease. Invasive disease was strongly associated with mortality (AOR 9.62; 95% CI: 2.16 -42.93).Conclusion: NDM-1 invasive disease is associated with significant mortality. Underlying co-morbidity, presence of invasive medical devices and exposure to antibiotics are important risk factors for NDM-1 invasive disease.

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