Virulence versus fitness determinants in Escherichia coli isolated from asymptomatic bacteriuria in healthy nonpregnant women

Srivastava, Shubhi; Agarwal, Jyotsna; Mishra, Bharti; Srivastava, Richa

doi:10.4103/0255-0857.174103

Cited by 7 publications

(3 citation statements)

References 21 publications

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“…Cases of symptomatic UTI are treated using empirical antimicrobials; whereas it remains unwarranted in asymptomatic UTIs except conditions like pregnancy or before any invasive urologic procedure. Moreover, the asymptomatic bacteriuria has been treated depending on the phylogenetic group of the microbes, virulence genes involved, pathogenic island, properties of biofilm formation and iron transport mechanism as documented earlier [14–16]. As previous studies reported, evolution of pathogenic E.…”

Section: Resultsmentioning

confidence: 99%

Virulence gene mutations as a differentiator of clinical phenotypes: insights from community-acquired uropathogenic Escherichia coli

et al. 2022

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Uropathogenic Escherichia coli (UPEC) remains an important cause of urinary tract infection during pregnancy. Multiple molecular virulence determinants and antibiotic resistant genes facilitate its pathogenesis and virulence phenotype. Hence it is hypothesized that there will be considerable variation in genes among the isolates from symptomatic as well as asymptomatic bacteriuria (ABU) during pregnancy. The aim of this study was to decipher the genetic variation among the two phenotypes. Six different UPEC isolates collected from urine specimens of consecutive pregnant females (five, symptomatic bacteriuria and one, ABU) were tested for their growth kinetics, and biofilm formation. A total of 87 virulence determinants and 56 antibiotic resistance genes were investigated using whole-genome sequencing, to identify putative drives of virulence phenotype. In this analysis, we identified eight different types of fully functional toxin antitoxin (TA) systems [HipAB, YefM-YoeB, YeeU-YeeV (CbtA), YhaV-PrlF, ChpBS, HigAB, YgiUT and HicAB] in the isolates from symptomatic bacteriuria; whereas partially functional TA system with mutations were observed in the asymptomatic one. Isolates of both the groups showed equivalent growth characteristics and biofilm-formation ability. Genes for an iron transport system (Efe UOB system, Fhu system except FhuA) were observed functional among all symptomatic and asymptomatic isolates, however functional mutations were observed in the latter group. Gene YidE was observed predominantly associated with the biofilm formation along with few other genes (BssR, BssS, YjgK, etc.). This study outlines putative critical relevance of specific variations in the genes for the TA system, biofilm formation, cell adhesion and colonization among UPEC isolates from symptomatic and asymptomatic bacteriuria among pregnant women. Further functional genomic study in the same cohort is warranted to establish the pathogenic role of these genes.

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Section: Resultsmentioning

confidence: 99%

Virulence gene mutations as a differentiator of clinical phenotypes: insights from community-acquired uropathogenic Escherichia coli

et al. 2022

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“…However, the virulence nature of these phylogroups can only be evaluated based on the occurrence of the virulence genes among the strains from these phylogroups. Among the mammalian hosts, the distribution of E. coli phylogroups was shown to be different and the probable reason for this was stated to be the environmental conditions such as host habitat, climate, diet, gut morphology, use of antimicrobial agents, and their effects on commensals in fecal flora [57]. The fecal flora which later colonizes the perineal and perianal area becomes the source of bacteria infecting or colonising the urinary tract, especially in females.…”

Section: Plos Onementioning

confidence: 99%

Demonstrating the utility of Escherichia coli asymptomatic bacteriuria isolates’ virulence profile towards diagnosis and management—A preliminary analysis

et al. 2022

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Asymptomatic bacteriuria (ASB) caused by Escherichia coli (E. coli) is a significant condition associated with pregnancy and is considered as prognostic for the development of symptomatic urinary tract infection (UTI). However, treating all ASB increases the use of antibiotics and leads to the development of multidrug resistance (MDR). Therefore, this study aimed to identify the distribution of UPEC associated virulence genes and antibiotic susceptibility among phylogroups of E. coli isolated from ASB in pregnancy. Moreover, the gene expression of selected virulence genes was also compared among two E. coli isolates (with different pathogenic potential) to determine its pathogenicity. One hundred and sixty E. coli isolates from midstream urine samples of pregnant women with ASB were subjected to PCR-based detection for its phylogroups and virulence genes. The antibiotic susceptibility of isolated strains was determined by the disc diffusion method. Expression of the virulence genes were determined through microarray analysis and quantitative Real-Time PCR. The prevalence of ASB in this study was 16.1%. Within ASB isolates, the occurrence of phylogroup B2 was the highest, and isolates from this group harboured most of the virulence genes studied. Overall, the most identified virulence genes among all phylogroups in descending order were fimH, chuA, kpsMTII, usp, fyuA, hlyA, iroN, cnf, papC, sfa, ompT, and sat. In this study, higher resistance to antibiotics was observed for ampicillin (77.5%), amoxicillin-clavulanate (54.4%), trimethoprim-sulfamethoxazole (46.9%) and amikacin (43.8%) compared to the other tested antibiotics and 51.9% of the tested isolates were MDR. Furthermore, hierarchical clustering and gene expression analysis demonstrated extreme polarization of pathogenic potential of E. coli causing ASB in pregnancy necessitating the need for bacterial isolate focused approach towards treatment of ASB.

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“…[1] The pathogenesis of UTI is complex and very often influenced by the host biological and behavioral factors as well as by virulence characteristics of the infecting uropathogen. [2] Members of the family Enterobacteriaceae are the most common organisms responsible for UTI. Escherichia coli is associated with nearly 80% of community-acquired and 50% of hospital-acquired UTIs.…”

Section: Introductionmentioning

confidence: 99%

Outcome of acute urinary tract infections caused by uropathogenic Escherichia coli with phenotypically demonstrable virulence factors

et al. 2019

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Background: Urinary tract infection (UTI) caused by uropathogenic Escherichia coli (UPEC) strains is one of the most important community-acquired infections in the world. The presence of virulence factors is closely related with the pathogenesis of UTI. Methods: The present study was conducted on 150 isolates of UPEC obtained from symptomatic and asymptomatic cases of UTIs with significant counts (≥10 5 CFU/ml) during 1 year. UPEC isolates were studied for hemolysis on 5% sheep blood agar, mannose-sensitive hemagglutination (MSHA), mannose-resistant hemagglutination (MRHA), and biofilm formation by recommended methods. Patients with UTI due to UPEC showing virulence factors were evaluated for the treatment received and the outcome of treatment. These were compared with the outcomes of patients whose culture samples grew UPEC without demonstrable virulence factors. Results: The study showed hemolysin production in 40% of the isolates. Forty percent of the isolates showed the presence of P fimbriae (MRHA) and 60% showed Type 1 fimbriae (MSHA). Biofilm formation capacity of all UPEC isolates was classified into three categories, strong biofilm producers (4%), moderate biofilm producers (88%), and nonbiofilm producers (8%). Patients harboring all three virulence factors showed 76% recovery compared to patients harboring strains with no demonstrable virulence factors, who showed 100% recovery. Conclusion: The present study has shown the production of various virulent factors and developing drug resistance in UPEC. Treatment outcomes of patients harboring strains with no virulence factors seem to be better than the ones which contain multiple virulence factors. UPEC occurs because of multiple virulence factors. Biofilm formation and MRHA are more likely to be seen in catheterized patients. The drug resistance among UPEC is on rise; therefore, the selection of appropriate antibiotics (after antibiotic susceptibility testing) is must for proper treatment of patients and to avoid emergence of drug resistance. Significant number of the UPEC isolates was sensitive to nitrofurantoin, and half of the isolates were sensitive to cotrimoxazole, so treatment is by giving these drugs orally.

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Virulence versus fitness determinants in Escherichia coli isolated from asymptomatic bacteriuria in healthy nonpregnant women

Cited by 7 publications

References 21 publications

Virulence gene mutations as a differentiator of clinical phenotypes: insights from community-acquired uropathogenic Escherichia coli

Virulence gene mutations as a differentiator of clinical phenotypes: insights from community-acquired uropathogenic Escherichia coli

Demonstrating the utility of Escherichia coli asymptomatic bacteriuria isolates’ virulence profile towards diagnosis and management—A preliminary analysis

Outcome of acute urinary tract infections caused by uropathogenic Escherichia coli with phenotypically demonstrable virulence factors

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