The Nutrient and Energy Pathway Requirements for Surface Motility of Nonpathogenic and Uropathogenic Escherichia coli

The distinct transcriptome of virulence-associated phylogenetic group B2 Escherichia coli

Escherichia coli strains of phylogenetic group B2 are often associated with urinary tract infections (UTIs) and several other diseases. Recent genomic and transcriptomic analyses have not suggested or identified specific genes required for virulence, but have instead suggested multiple virulence strategies and complex host-pathogen interactions. Previous analyses have not compared core gene expression between phylogenetic groups or between pathogens and nonpathogens within phylogenetic groups. We compared the core gene expression of 35 strains from three phylogenetic groups that included both pathogens and nonpathogens after growth in a medium that allowed comparable growth of both types of strains. K-means clustering suggested a B2 cluster with 17 group B2 strains and two group A strains; an AD cluster with six group A strains, five group D strains and one B2 strain; and four outliers which included the highly studied model uropathogenic E. coli strains UTI89 and CFT073. Half of the core genes were differentially expressed between B2 and AD cluster strains, including transcripts of genes for all aspects of macromolecular synthesis-replication, transcription, translation, and peptidoglycan synthesis-energy metabolism, and environmental-sensing transcriptional regulators. Notably, core gene expression between nonpathogenic and uropathogenic transcriptomes within phylogenetic groups did not differ. If differences between pathogens and nonpathogens exist, then the differences do not require transcriptional reprogramming. In summary, B2 cluster strains have a distinct transcription pattern that involves hundreds of genes. We propose that this transcription pattern is one factor that contributes to virulence. IMPORTANCE Escherichia coli is a diverse species and an opportunistic pathogen that is associated with various diseases, such as urinary tract infections. When examined, phylogenetic group B2 strains are more often associated with these diseases, but the specific properties that contribute to their virulence are not known. From a comparative transcriptomic analysis, we found that group B2 strains grown in a nutrient-rich medium had a distinct transcription pattern, which is the first evidence that core gene expression differs between phylogenetic groups. Understanding the consequences of group B2 transcription pattern will provide important information on basic E. coli biology, the basis for E. coli virulence, and possibly for developing therapies for a majority of urinary tract infections and other group B2-associated diseases.

Impact of inappropriate empirical antibiotic treatment on clinical outcomes of urinary tract infections caused by Escherichia coli: a retrospective cohort study

OBJECTIVES

We aimed to determine the clinical impact of inappropriate empirical antibiotic treatment (IEAT) compared with appropriate empirical antibiotic treatment (AEAT) in hospitalised patients with urinary tract infections (UTIs) caused by Escherichia coli (E. coli).

METHODS

This retrospective cohort study included adult patients with a primary diagnosis of UTI who were treated with empirical antibiotics at a tertiary hospital in southern China over a 2-year period. Clinical data of patients who received IEAT were compared with those of patients receiving AEAT. We used multivariable logistic regression to identify the predictors for receiving IEAT and the risk factors affecting clinical outcomes.

RESULTS

A total of 213 patients were enrolled (median age, 61 years), of whom 103 (48.4%) received IEAT. IEAT was associated with empirical use of fluoroquinolones, male sex and age-adjusted Charlson comorbidity index (aCCI) score >6. Hospital length of stay (LOS) was longer for patients who received IEAT than for those who received AEAT (13.6 ± 8.6 days vs. 10.8 ± 7.9 days; P = 0.008). IEAT was an independent risk factor for longer LOS along with aCCI score ≥2, lung disease and cardiac disease.

CONCLUSION

Empirical use of fluoroquinolones for UTIs should be avoided, especially in male patients with aCCI score >6. Improved empirical antimicrobial therapy may have a beneficial impact in reducing bacterial resistance and healthcare costs by decreasing the LOS. Therefore, interventions to promote in-depth antibiotic stewardship programmes in China are needed.