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

Biofilm Formation by Escherichia coli Isolated from Urinary Tract Infections from Aguascalientes, Mexico

Uropathogenic Escherichia coli (UPEC) strains are among the leading causes of urinary tract infections (UTIs) worldwide. They can colonize the urinary tract and form biofilms that allow bacteria to survive and persist, causing relapses of infections and life-threatening sequelae. Here, we analyzed biofilm production, antimicrobial susceptibility, virulence factors, and phylogenetic groups in 74 E. coli isolated from diagnosed patients with UTIs to describe their microbiological features and ascertain their relationship with biofilm capabilities. High levels of ceftazidime resistance are present in hospital-acquired UTIs. Isolates of multidrug resistance strains (p = 0.0017) and the yfcV gene (p = 0.0193) were higher in male patients. All the strains tested were able to form biofilms. Significant differences were found among higher optical densities (ODs) and antibiotic resistance to cefazolin (p = 0.0395), ceftazidime (p = 0.0302), and cefepime (p = 0.0420). Overall, the presence of fimH and papC coincided with strong biofilm formation by UPEC. Type 1 fimbriae (p = 0.0349), curli (p = 0.0477), and cellulose (p = 0.0253) production was significantly higher among strong biofilm formation. Our results indicated that high antibiotic resistance may be related to male infections as well as strong and moderate biofilm production. The ability of E. coli strains to produce biofilm is important for controlling urinary tract infections.

Correlation of biofilm formation, virulence factors, and phylogenetic groups among Escherichia coli strains causing urinary tract infection: A global systematic review and meta-analysis

Background

Different virulence factors are involved in the pathogenesis of urinary tract infection (UTI) caused by Uropathogenic Escherichia coli (UPEC); hence, this study aimed to study the prevalence of biofilm formation, virulence factors, and phylogenetic groups and their correlation with biofilm formation among UPEC isolates through a systematic review and meta-analysis.

Materials and Methods

A literature search was conducted from 1, 2000, to the end of 2021 in different databases for studies that reported biofilm together with virulence genes or phylogenetic groups in UPEC isolates from patients with UTI according to PRISMA protocol. Data were analyzed by Comprehensive meta-analysis software.

Results

The pooled prevalence of biofilm formers was 74.7%. The combined prevalence of phylogenetic Groups A, B1, B2, and D (s) were reported at 19.6%, 11%, 50.7%, and 20.5%, respectively. The most common virulence genes reported worldwide were fimA, ecpA, and fimH, with a combined prevalence of 90.3%, 86.6%, and 64.9%, respectively. The pooled prevalence of biofilm formation in UPEC isolates with phylogenetic Groups A, B1, B2, D, C, and F were 12.4%, 8.7%, 33.7%, 12.4%, 2.6%, and 2.65%, respectively. Several studies showed a correlation between biofilm production and virulence genes, or phylogenetic groups.

Conclusion

Regarding data obtained, the high level of combined biofilm formation (74.7%) and the presence of a positive correlation between biofilm production and virulence genes, or phylogenetic groups as reported by the most studies included in the present review, indicates an important role of biofilm in the persistence of UPEC in the UTI.

Characterization of unconventional pathogenic Escherichia coli isolated from bloodstream infection: virulence beyond the opportunism

Extraintestinal pathogenic Escherichia coli (ExPEC) is the leading cause of urinary tract infection worldwide and a critical bloodstream infection agent. There are more than 50 virulence factors (VFs) related to ExPEC pathogenesis; however, many strains isolated from extraintestinal infections are devoid of these factors. Since opportunistic infections may occur in immunocompromised patients, E. coli strains that lack recognized VFs are considered opportunist, and their virulence potential is neglected. We assessed eleven E. coli strains isolated from bloodstream infections and devoid of the most common ExPEC VFs to understand their pathogenic potential. The strains were evaluated according to their capacity to interact in vitro with human eukaryotic cell lineages (Caco-2, T24, HEK293T, and A549 cells), produce type 1 fimbriae and biofilm in diverse media, resist to human sera, and be lethal to Galleria mellonella. One strain displaying all phenotypic traits was sequenced and evaluated. Ten strains adhered to Caco-2 (colon), eight to T24 (bladder), five to HEK-293 T (kidney), and four to A549 (lung) cells. Eight strains produced type 1 fimbriae, ten adhered to abiotic surfaces, nine were serum resistant, and seven were virulent in the G. mellonella model. Six of the eleven E. coli strains displayed traits compatible with pathogens, five of which were isolated from an immune-competent host. The genome of the EC175 strain, isolated from a patient with urosepsis, reveals that the strain belonged to ST504-A, and serotype O11:H11; harbors thirteen VFs genes, including genes encoding UpaG and yersiniabactin as the only ExPEC VFs identified. Together, our results suggest that the ExPEC pathotype includes pathogens from phylogroups A and B1, which harbor VFs that remain to be uncovered.

High Virulence and Multidrug Resistance of Escherichia coli Isolated in Periodontal Disease

Periodontal disease is caused by different gram-negative anaerobic bacteria; however, Escherichia coli has also been isolated from periodontitis and its role in periodontitis is less known. This study aimed to determine the variability in virulence genotype, antibiotic resistance phenotype, biofilm formation, phylogroups, and serotypes in different emerging periodontal strains of Escherichia coli, isolated from patients with periodontal disease and healthy controls. E. coli, virulence genes, and phylogroups, were identified by PCR, antibiotic susceptibility by the Kirby-Bauer method, biofilm formation was quantified using polystyrene microtiter plates, and serotypes were determined by serotyping. Although E. coli was not detected in the controls (n = 70), it was isolated in 14.7% (100/678) of the patients. Most of the strains (n = 81/100) were multidrug-resistance. The most frequent adhesion genes among the strains were fimH and iha, toxin genes were usp and hlyA, iron-acquisition genes were fyuA and irp2, and protectin genes were ompT, and KpsMT. Phylogroup B2 and serotype O25:H4 were the most predominant among the strains. These findings suggest that E. coli may be involved in periodontal disease due to its high virulence, multidrug-resistance, and a wide distribution of phylogroups and serotypes.

Phylogenicity and Virulence Profiles of Clinical Escherichia coli Isolates in the Ho Teaching Hospital of Ghana

Background. Escherichia coli bacteria are Gram-negative, non-spore-forming aerobes or facultative anaerobic rods. Some strains are pathogenic in men while others are commensals in the gut. The pathogenic strains cause a wide array of diseases by virtue of virulence factors. The commensal strains are generally categorized into phylogenetic groups A and B1. The aim of this study was to determine the association between phylogeny of E. coli isolates and virulence and sociodemographic characteristics of the study subjects. Method. This study was a cross-sectional study carried out from July 2018 to June 2019. E. coli isolates obtained from different clinical specimens were subjected to polymerase chain reaction to determine their phylogenetic groupings and virulence. Results. The majority of the isolates belonged to phylogroup A 101 (74.8%), and the predominant virulent gene was fimA (88.9%). There was no significant correlation between phylogenicity and virulence, except for chuA which was found in all isolates that belonged to phylogroups clade I and D. None of the 101 isolates that belonged to group A had the chuA virulence gene. There was a significant association between patient age category and phylogenetic groups B1 and D. Conclusions. This study assessed the relationship between the phylogenetic distribution and the virulence profile of clinical isolates of E. coli. The virulence of isolates belonging to phylogroup A, which are generally considered as commensals, is alarming. Measures must therefore be put in place to control the spread of these virulent E. coli.

Antimicrobial Resistance Pattern in E. coli Isolated from Placental Tissues of Pregnant Women in Low-Socioeconomic Setting of Pakistan

Infections during pregnancy can culminate in adverse pregnancy outcomes, including preterm birth (PTB). Pakistan is among the top ten nations with high PTB-associated neonatal mortality rates, where access to prenatal as well as neonatal care is only afforded by the privileged few. Societal stigma further discourages women seeking healthcare for minor infections. Microbial pathogens associated with genitourinary infections can lead to gestational complications culminating in earlier onset of labor. In this study, association of Escherichia coli (E. coli) with PTB in Pakistani women of low-socioeconomic status is examined. 57 paired vaginal swabs and placenta samples from mothers with full term and preterm deliveries were collected and processed for isolation and molecular characterization of extraintestinal pathogenic E. coli (ExPEC). ExPEC isolated from vaginal swabs and placenta showed phylotype B2 being most prevalent (Vagina n = 3 (9), 33%) (Placenta n = 4 (12), 33%) in preterm cases followed by phylotype B1 (Vagina n = 2 (9), 22%) (Placenta n = 3 (12), 25%) and untypeable strains. Antibiotic susceptibility profiling showed a large percentage of resistant isolates to multiple antibiotics, including carbapenem and included extended-spectrum beta-lactamase (ESBL) producers. Our study is the first to report different phylotypes of E. coli from placental tissues in preterm deliveries which may be a cause for concern for maternal and neonatal health. ExPEC from vaginal swabs and placental of females delivering preterm shows the pathogenic phylotype B2 dominance with a large percentage of isolates resistant to multiple antibiotics, including carbapenem and included ESBL producers. The placental isolates may indicate ascending infection from vagina or urinary tract which may lead to preterm birth.

Molecular Epidemiology and Presence of Hybrid Pathogenic Escherichia coli among Isolates from Community-Acquired Urinary Tract Infection

Urinary tract infections (UTI) affect community and healthcare patients worldwide and may have different clinical outcomes. We assessed the phylogenetic origin, the presence of 43 virulence factors (VFs) of diarrheagenic and extraintestinal pathogenic Escherichia coli, and the occurrence of hybrid strains among E. coli isolates from 172 outpatients with different types of UTI. Isolates from phylogroup B2 (46%) prevailed, followed by phylogroups A (15.7%) and B1 (12.2%), with similar phylogenetic distribution in symptomatic and asymptomatic patients. The most frequent VFs according to their functional category were fimA (94.8%), ompA (83.1%), ompT (63.3%), chuA (57.6%), and vat (22%). Using published molecular criteria, 34.3% and 18.0% of the isolates showed intrinsic virulence and uropathogenic potential, respectively. Two strains carried the eae and escV genes and one the aggR gene, which classified them as hybrid strains. These hybrid strains interacted with renal and bladder cells, reinforcing their uropathogenic potential. The frequency of UPEC strains bearing a more pathogenic potential in the outpatients studied was smaller than reported in other regions. Our data contribute to deepening current knowledge about the mechanisms involved in UTI pathogenesis, especially among hybrid UPEC strains, as these could colonize the host’s intestine, leading to intestinal infections followed by UTI.

Genetic and Virulence Characteristics of a Hybrid Atypical Enteropathogenic and Uropathogenic Escherichia coli (aEPEC/UPEC) Strain

Hybrid strains of Escherichia coli combine virulence traits of diarrheagenic (DEC) and extraintestinal pathogenic E. coli (ExPEC), but it is poorly understood whether these combined features improve the virulence potential of such strains. We have previously identified a uropathogenic E. coli (UPEC) strain (UPEC 252) harboring the eae gene that encodes the adhesin intimin and is located in the locus of enterocyte effacement (LEE) pathogenicity island. The LEE-encoded proteins allow enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC) to form attaching and effacing (A/E) lesions in enterocytes. We sought to characterize UPEC 252 through whole-genome sequencing and phenotypic virulence assays. Genome analysis unveiled that this strain harbors a complete LEE region, with more than 97% of identity comparing to E2348/69 (EPEC) and O157:H7 Sakai (EHEC) prototype strains, which was functional, since UPEC 252 expressed the LEE-encoded proteins EspB and intimin and induced actin accumulation foci in HeLa cells. Phylogenetic analysis performed comparing 1,000 single-copy shared genes clustered UPEC 252 with atypical EPEC strains that belong to the sequence type 10, phylogroup A. Additionally, UPEC 252 was resistant to the bactericidal power of human serum and colonized cells of the urinary (T24 and HEK293-T) and intestinal (Caco-2 and LS174T) tracts. Our findings suggest that UPEC 252 is an atypical EPEC strain that emerges as a hybrid strain (aEPEC/UPEC), which could colonize new niches and potentially cause intestinal and extraintestinal infections.

Association Between Kinetics of Early Biofilm Formation and Clonal Lineage in Escherichia coli

Background

Escherichia coli biofilm formation has mostly been assessed in specific pathogenic E. coli groups. Here, we assessed the early biofilm formation (EBF), i.e., adhesion stage, using the BioFilm Ring Test^® on 394 E. coli clinical isolates (EC) [196 consecutively isolated (CEC) in 2016 and 198 ESBL-producing E. coli (ESBLEC) isolated in 2015]. Then, biofilm-forming ability was contrasted with phylogroups, clonotypes (fumC-fimH), and sequence types (STs), all being used to define clones, virulence factors (VF), and FimB.

Result

According to both biofilm production levels at 2, 3, and 5 h, and EBF kinetics over 5 h, CEC and ESBLEC isolates segregated into three EBF groups: strong (G1), moderate (G2), and weak (G3) producers. At 2 h, strong producers were more frequent among CEC (n = 28; 14.3%) than among ESBLEC (n = 8; 4%) (P = 0.0004). As CEC and ESBLEC isolates showed similar individual EBF kinetics in each group, a comparison of isolate features between each group was applied to gathered CEC and ESBLEC isolates after 2 h of incubation, 2 h being the most representative time point of the CEC and ESBLEC isolate segregation into the three groups. Phylogroup B2 displayed by 51.3% of the 394 isolates was more frequent in G1 (77.8%) than in G3 (47.6%) (P = 0.0006). The 394 isolates displayed 153 clones, of which 31 included at least three isolates. B2-CH14-2-ST127, B2-CH40-22-ST131, B2-CH52-5/14-ST141, and E-CH100-96-ST362 clones were associated with G1 (P < 0.03) and accounted for 41.7% of G1 isolates. B2-CH40-30-ST131 clone was associated with G3 (P < 0.0001) and accounted for 25.5% of G3 isolates. VF mean was higher among G1 than among G3 isolates (P < 0.001). FimB-P2 variant was associated with G1 (P = 0.0011) and FimB-P1 variant was associated with G3 (P = 0.0023). Clone, some VF, and FimB were associated with EBF, with clonal lineage being able to explain 72% of the variability of EBF.

Conclusion

Among our 394 isolates, <10% are able to quickly and persistently produce high biofilm levels over 5 h. These isolates belong to a few clones previously described in various studies as dominant gut colonizers in mammalians and birds and comprised the B2-CH40-22-ST131 clone, i.e., the ancestor of the globally disseminated B2-CH40-30-ST131 clone that is the dominant clone among the weak biofilm producers.

Multidrug- and Extensively Drug-Resistant Uropathogenic Escherichia coli Clinical Strains: Phylogenetic Groups Widely Associated with Integrons Maintain High Genetic Diversity

In recent years, an increase of uropathogenic Escherichia coli (UPEC) strains with Multidrug-resistant (MDR) and Extensively Drug-resistant (XDR) profiles that complicate therapy for urinary tract infections (UTIs) has been observed and has directly impacted costs and extended hospital stays. The aim of this study was to determine MDR- and XDR-UPEC clinical strains, their virulence genes, their phylogenetic groups and to ascertain their relationship with integrons and genetic diversity. From a collection of 500 UPEC strains, 103 were selected with MDR and XDR characteristics. MDR-UPEC strains were mainly associated with phylogenetic groups D (54.87%) and B2 (39.02%) with a high percentage (≥70%) of several fimbrial genes (ecpA, fimH, csgA, and papGII), an iron uptake gene (chuA), and a toxin gene (hlyA). In addition, a moderate frequency (40–70%) of other genes (iutD, tosA, and bcsA) was observed. XDR-UPEC strains were predominantly associated with phylogenetic groups B2 (47.61%) and D (42.85%), which grouped with ≥80 virulence genes, including ecpA, fimH, csgA, papGII, iutD, and chuA. A moderate frequency (40–70%) of the tosA and hlyA genes was observed. The class 1 and 2 integrons that were identified in the MDR- and XDR-UPEC strains were associated with phylogenetic groups D, B2, and A, while the XDR-UPEC strains that were associated with phylogenetic groups B2, D, and A showed an extended-spectrum beta-lactamase (ESBL) phenotype. The modifying enzymes (aadA1, aadB, aacC, ant1, dfrA1, dfrA17, and aadA4) that were identified in the variable region of class 1 and 2 integrons from the MDR strains showed resistance to gentamycin (56.25 and 66.66%, respectively) and trimethoprim-sulfamethoxazole (84.61 and 66.66%, respectively). The MDR- and XDR-UPEC strains were distributed into seven clusters and were closely related to phylogenic groups B2 and D. The diversity analysis by PFGE showed 42.68% of clones of MDR-UPEC and no clonal association in the XDR-UPEC strains. In conclusion, phylogenetic groups including virulence genes are widely associated with two integron classes (1 and 2) in MDR- and XDR-UPEC strains.

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

PURPOSE

Escherichia coli isolated from asymptomatic bacteriuria (ABU) correlated genotypically and phenotypically with cystitis isolates may help in distinguishing urovirulence determinants from 'fitness factors', latter necessary only for survival of E. coli in urinary tract; for gaining insight into the pathogenesis of urinary tract infection.

MATERIALS AND METHODS

In this cross-sectional study, we compared genotypic (phylogroups and 15 putative virulence genes), and phenotypic profiles of ABU E. coli strains with our previously genotyped collection of cystitis isolates. Virulence score was calculated for each isolate as a number of virulence genes detected.

RESULTS

Significant differences were observed in the proportion of four phylogenetic groups (P=0.009) amongst cystitis and ABU isolates. Average virulence score was higher for ABU isolates (6.6) than cystitis strains (4.2); and hlyA (P=0.001), cytotoxic necrotising factor 1 (P=0.00), fyuA (P=0.00), ibeA (P=0.00), kpsMII (P=0.01), and malX/pathogenicity-associated island (P=0.01) were more frequently present in ABU strains.

CONCLUSIONS

The expression of adhesins, haemolysin, aerobactin, and capsule synthesis gene were similar in two groups suggesting their role as fitness factors. ABU isolates were better biofilm producers, reflecting its importance in silent persistence. Serum resistance gene which was more expressed in cystitis isolates may represent virulence determinant. Genetic makeup of E. coli does not change much rather genes helping in survival and colonisation are expressed equally in ABU and cystitis isolates as opposed to phenotypic attenuation of those that helps in invasion or inflammation in ABU isolates.

Virulence determinants in Escherichia coli associated with recurrent cystitis in sexually active women

More than a quarter of women who experience acute cystitis develop recurrence but information on specific urovirulent genetic profile of uropathogenic Escherichia coli associated with recurrent cystitis is still limited. In this prospective cohort study, index episode E. coli from a cohort of 46 sexually active women with acute cystitis who reported recurrence during followup were grouped into repeat infection (RI) and single infection (SI) isolates, based on enterobacterial repetitive intergenic consensus (ERIC) PCR profile comparison with subsequent E. coli isolated from same women. PCR for phylogrouping and 15 virulence genes along with test for biofilm formation were done. Virulence score was calculated for each isolate as number of virulence genes detected. Among 46 index E. coli, 22 were RI, and 24 were SI isolates. RI isolates had phylogroup B2 as majority (54.5%) which is typically described as more virulent phylogroup and virulence score for RI isolates was also significantly higher compared to SI isolates. Virulence gene malX (p = 0.03) was significantly associated with RI isolates. 68.2% RI isolates were strong to moderate biofilm producers in comparison to 33.3% SI isolates, an important survival strategy to reside in bladder and or vagina. Overall, E. coli associated with recurrent cystitis appear to be more virulent and malX seems to have a role in causing repeat infection.

Role of special pathogenicity versus prevalence theory in pathogenesis of acute cystitis caused by Escherichia coli

Escherichia coli is the most common pathogen causing acute cystitis in sexually active women. Human faeces are generally considered the primary reservoir for infection and the faecal-perineal-urethral pathway is the accepted route of infection. Two theories have been proposed for the pathogenesis of acute cystitis: (1) special pathogenicity, where uropathogenic E. coli (UPEC) encoding special virulence factors causes infection; and (2) prevalence, wherein ordinary faecal E. coli causes infection by simple mass action. The aim of this study was to compare concurrent urinary E. coli isolates from women with acute cystitis with their own dominant faecal, vaginal E. coli isolates; thus, these patients served as their own control. E. coli isolates from 80 women were analysed by phylotyping, virulence profiling (for 15 putative virulence genes) and enterobacterial repetitive intergenic consensus (ERIC) PCR. A virulence score was calculated for each isolate based on the number of virulence genes detected. Four host ecological groups of E. coli were created on the basis of ERIC PCR: group UVF, where vaginal and faecal isolates yielded the infecting urine clone; group UV, where only vaginal isolates yielded the infecting urine clone; group UF, where faecal isolates yielded the infecting urine clone; and group U, where the infecting urine clone was distinct. In the majority of cases the infecting E. coli clone from urine was also the dominant faecal clone (56.3%; groups UVF and UF possessing high virulence scores of 4.6 and 3.9, respectively), indicating that both mechanisms play a role in pathogenesis. Non-dominant yet virulent faecal clones or an external source of E. coli seems a possibility in the UV group (13.7%, VF score 4.8). In 30% of patients (U group) the infecting urine clone was non-dominant and possessed a low virulence score (2.7); suggesting a possible role for host factors in establishing infection.