Virulence characteristics and phylogenetic background of ciprofloxacin resistant Escherichia coli in the urine samples from Korean women with acute uncomplicated cystitis

Fluoroquinolone-Resistant Sequence Type 131 Subgroups O25b and O16 Among Extraintestinal Escherichia coli Isolates from Community-Acquired Urinary Tract Infections

The multidrug-resistant sequence type 131 (ST131) Escherichia coli is a spreading epidemiological burden particularly among isolates resistant to fluoroquinolones. We aimed to evaluate the commonality of ST131-O25b and ST131-O16 among fluoroquinolone-resistant E. coli isolates causing community-acquired urinary tract infections (UTIs) at Fayoum University Hospital, in Egypt. Ninety-two fluoroquinolone-resistant E. coli isolates were subjected to multiplex PCR for detection of ST131 of either O25b or O16 subgroups. Positive isolates were then assessed for antimicrobial susceptibility and virulence genotyping. Out of 92 fluoroquinolone-resistant E. coli isolates, 56 (60.9%) isolates were O25b/O16 subgroups of ST131, including 44 (78.6%) ST131-O25b and 12 (21.4%) ST131-O16 subgroups. All the O25b/O16 ST131 isolates were sensitive to meropenem, where ST131-O25b isolates were significantly more resistant to extended spectrum cephalosporins compared to S131-O16 strains. All the O25b/O16 ST131 isolates harbored three or more of the virulence factors associated with extraintestinal pathogenic E. coli status. ST131-O16 showed a significantly higher virulence score than ST131-O25b isolates. Our results bring to highlight the emergence of O25b/O16 ST131 isolates between community acquired UTIs among Egyptian patients. This is the first report for the presence of O16 isolates in Egypt, showing a lower predominance than the O25b subgroup. The high prevalence of O25b/O16 ST131 isolates requires strict stewardship on antimicrobial use, notably fluoroquinolones, to control the endemicity of such emerging multidrug-resistant clone in the community.

Network Analysis Reveals Sex- and Antibiotic Resistance-Associated Antivirulence Targets in Clinical Uropathogens

Increasing antibiotic resistance among uropathogenic Escherichia coli (UPEC) is driving interest in therapeutic targeting of nonconserved virulence factor (VF) genes. The ability to formulate efficacious combinations of antivirulence agents requires an improved understanding of how UPEC deploy these genes. To identify clinically relevant VF combinations, we applied contemporary network analysis and biclustering algorithms to VF profiles from a large, previously characterized inpatient clinical cohort. These mathematical approaches identified four stereotypical VF combinations with distinctive relationships to antibiotic resistance and patient sex that are independent of traditional phylogenetic grouping. Targeting resistance- or sex-associated VFs based upon these contemporary mathematical approaches may facilitate individualized anti-infective therapies and identify synergistic VF combinations in bacterial pathogens.

Cystitis: from urothelial cell biology to clinical applications

Cystitis is a urinary bladder disease with many causes and symptoms. The severity of cystitis ranges from mild lower abdominal discomfort to life-threatening haemorrhagic cystitis. The course of disease is often chronic or recurrent. Although cystitis represents huge economical and medical burden throughout the world and in many cases treatments are ineffective, the mechanisms of its origin and development as well as measures for effective treatment are still poorly understood. However, many studies have demonstrated that urothelial dysfunction plays a crucial role. In the present review we first discuss fundamental issues of urothelial cell biology, which is the core for comprehension of cystitis. Then we focus on many forms of cystitis, its current treatments, and advances in its research. Additionally we review haemorrhagic cystitis with one of the leading causative agents being chemotherapeutic drug cyclophosphamide and summarise its management strategies. At the end we describe an excellent and widely used animal model of cyclophosphamide induced cystitis, which gives researches the opportunity to get a better insight into the mechanisms involved and possibility to develop new therapy approaches.

Molecular Characterization of Uropathogenic Escherichia coli: Nalidixic Acid and Ciprofloxacin Resistance, Virulent Factors and Phylogenetic Background

BACKGROUND AND OBJECTIVE

A proficient pathogen should be virulent, resistant to antibiotics, and epidemic. However, the interplay between resistance and virulence is poorly understood. Perhaps, the most commonly accepted view is that resistance to quinolones is linked to a loss of virulence factors. However, the low virulent phylogenetic groups may be more prone to acquire resistance to quinolones. The aim of this study was to identify and characterise the Nalidixic Acid (NA) and ciprofloxacin (CIP) resistant uropathogenic Escherichia coli (UPEC) isolates with respect to virulence and phylogenetic background, from hospital settings in Kolkata, an eastern region in India. Research based on these bacterial populations will help in understanding the molecular mechanisms underlying the association between resistance and virulence, that in turn, may help in managing the future disseminations of UTIs in their entirety.

MATERIAL AND METHODS

One hundred and ten E. coli isolates were screened against NA and CIP using Kirby-Bauer disk diffusion technique, following CLSI guidelines. Prevalence of virulent factor genes and distribution of phylogenetic groups amongst the isolates was determined by PCR, using gene specific primers against the different virulent factors and DNA markers (chuA, yjaA and DNA fragment, TSPE4.C2) respectively. Statistical analysis of the data was performed using SPSS software.

RESULTS

Resistance to both NA and CIP was reported in 75.5 % of the isolates which were analysed. The virulent determinants, papC, pap GII, papEF, afa, cnf1, hlyA and iroN were significantly predominant in the drug susceptible than the resistant isolates. A significant reduction of phylogroup B2 in NA (85.7% versus 64.6%, χ(2)P<0.001) and CIP (85.2 % versus 61.4%, χ(2)P<0.001) resistant UPEC isolates, followed by increase in predominance of non-B2 phylotypes (group D and group B1), were observed.

CONCLUSION

This is the first report from India that has indicated possible evidence on horizontal gene transfer from pathogenic to commensal strains and selection of the latter, on extensive usage of this group of antimicrobials in hospital settings, where these drugs were routinely prescribed for treating urinary tract infection. Therefore, this information necessitates surveillance programs and administration of effective strategies, to put an end to random prescription policies involving this group of antimicrobials.

Genotypic characteristics and biofilm formation among Escherichia coli isolates from Indian women with acute cystitis

BACKGROUND

The purpose of present study was to characterize uropathogenic Escherichia coli (UPEC) associated with acute cystitis in Indian women.

METHODS

In this prospective descriptive study we investigated phylogenetic background and virulence genotypes for 15 genes by multiplex PCR and in vitro biofilm formation ability of 172 E. coli strains and explored possible association amongst them.

RESULTS

Most isolates (81, 47.1%) belonged to group B2 and A (50, 29.1%); few were from groups B1 (22, 12.7%) and D (19, 11.1%). The mean virulence scores of phylogroups A, B1, B2 and D were 3.3, 4.0, 4.6 and 4.9, respectively. We found higher prevalence of fimH, traT iutA, kpsMII, papG allele II and fyuA genes indicating putative role of adhesins, iron acquisition systems and protectins in causing bladder infection. Total 145 (84.3%) isolates produced biofilm; majority were weak biofilm producers and there was no significant difference in intensity and biofilm formation ability amongst various phylogroups or virulence scores. The phylogenetic distribution was different from western studies, including a lower prevalence of group B2 (dominant but not a majority), followed by group A, and some traditionally group B2-associated virulence genes were more prevalent in phylogroup A isolates.

CONCLUSIONS

Distribution of virulence genotypes and phylotypes can vary with geographical location and the isolates from western countries cannot be treated as prototypes for Asian cystitis isolates.