Genes papG Research Articles

The presence of virulence factor genes downregulates uterine AQP3 and alters glutathione peroxidase activity and uterine histopathology in canine pyometra.

Present study was designed to evaluate the role of virulence factor genes (papG, cnf1 and hylA) in the pathogenesis of canine pyometra. Antimicrobial susceptibility test and detection of virulence genes were performed Escherichia coli (E. coli) detected in uterine swab samples. Animals were divided into two groups based on the presence (VF+, n:14) or absence (VF-, n:7) of the virulence factor genes papG, cnf1 and hylA. Blood and tissue glutathione peroxidase activity, uterine histopathologic analysis and AQP3, ESR1, PGR, OXTR gene expressions were determined in both groups. Statistical analyses were performed using Stata version 15.1. All E. coli isolates were susceptible to amikacin, whereas resistant to ampicillin, amoxicillin/clavulanic acid and lincomycin. None of the isolates were susceptible to cefotaxime. E. coli isolates had at least one virulence gene. The most prevalent gene was fimH (100%), followed by fyuA (95.8%), usp (83.3%), sfa (75%), cnf1 and hlyA (70.8%) genes. Blood GPx activity was greater in VF+ animals. On the other hand, uterine tissue GPx activity was lower in VF+ group compared to the control group. Expression levels of AQP3 were upregulated more than fivefold in VF-dogs compared to the control group. In addition, AQP3 expression levels were found approximately threefold higher in VF (-) than VF (+) group (p < .05). Varying degree of inflammation noted for all animals with pyometra, but the presence of bacteria noted only in VF+ animals. In conclusion, the presence of virulence factor genes does not play a role in the histopathological degree of inflammation, the presence of bacteria was found to vary. Serum GPx activity increased in VF+ animals. While the hormone receptor expressions were similar, AQP expression was upregulated in the absence of virulence factor genes.

Targeting of Uropathogenic Escherichia coli papG gene using CRISPR-dot nanocomplex reduced virulence of UPEC

Urinary tract infections (UTI) are the most common infectious diseases in the world. It is becoming increasingly tough to treat because of emergence of antibiotic resistance. So, there is an exigency to develop novel anti-virulence therapeutics to combat multi-drug resistance pathogenic strains. Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) discovery has revolutionized the gene editing technology for targeted approach. The greatest obstacle for CRISPR/Cas9 is cargo delivery systems and both viral and plasmid methods have disadvantages. Here, we report a highly efficient novel CRISPR based gene editing strategy, CRISPR-dots for targeting virulence factor Fimbrial Adhesion (papG gene), the bacterial adhesion molecule. Carbon quantum dots (CQD) were used as a delivery vehicle for Cas9 and gRNA into CFT073, a UPEC strain. CQDs were covalently conjugated to cas9 and papG-targeted guide RNA (gRNA) forming a nanocomplex CRISPR-dots (Cri-dots) as confirmed by DLS and transmission electron microscopy. Cri-dots-papG significantly targeted papG as demonstrated by decrease in the expression of papG.Further papG deficient UPEC had significantly reduced adherence ability and biofilm forming ability as demonstrated by fluorescence microscopy and scanning electron microscopy. Also, papG deficient UPEC had reduced virulence as shown by significantly increased survival of Caenorhabditis elegans (C. elegans) worms compared to UPEC. Our findings suggest that targeting of papG gene using Cri-dots nanocomplexes significantly reduced the pathogenicity of UPEC. Thus, Cri-dots nanocomplex offer a novel anti-bacterial strategy against multi-drug resistant UPEC.

Carbon Quantum Dots Conjugated CRISPR-cas9-gRNA Antimicrobials Against Antibiotic Resistant Uropathogenic Escherichia coli

Background: Urinary tract infections (UTIs) are among the most common bacterial infections. UTI, although treatable, is now becoming increasingly tough to control because of rampant antimicrobial resistance in the Enterobacteriaceae family, particularly inEscherichia coli. Due to increased resistance, there is an exigency to develop novel therapeutic targets to combat these resistance strains. Clustered regularly interspaced short palindromic repeats (CRISPR)-technology has emerged as an important tool for gene editing based therapeutics. Methods: Here, we report an efficient gene editing strategy based on direct delivery of Cas9 and gRNA into Uropathogenic E. coli (UPEC) isolate. P-fimbriae plays major role in bacterial adherence to the uroepithelium through the Galα1-4Gal-binding PapG adhesin. We have covalently conjugated cas9 protein with CQD’s using EDC/NHS chemistry and targeted papG gene by synthesizing sequence specific complimentary gRNA. The targeting efficiency was confirmed by performing adherence assay, biofilm assay, flow cytometry and qRT-PCR. Results: There is a significant reduction of adherence ability of papG mutant strain as compared to control observed through microscopy. Also, significant reduction in biofilm formation (p-value &lt; 0.001) was noticed in treated sample (0.565 ± 0.003) vs control (1.020± 0.008). The relative qRT-PCR data of knockdown strains (p&lt;0.05) also revealed the dramatic decrease in the expression of papG gene, taking 16s rRNA gene as an endogenous control for normalization. The same result was observed from flow cytometry and SEM analysis. Conclusion: Hence, we conclude that CQD-CRISPR-Cas9-gRNA could be a novel therapeutic strategy for the eradication or treatment of antibiotic resistant pathogenic E. coli-based pathologies.

Evaluating the prevalence of virulence genes of Escherichia coli in patients affected by urinary tract infection

Urinary tract infection due to Escherichia coli remains to be a major health problem worldwide. UPEC is one of the major causes of urinary tract infections among the general public. These bacteria have various virulence factors, including adhesion and toxins. Pilli P and FimA are the main members of E. coli adhesion in the pathogenesis of urinary tract infections. Due to high prevalence of urinary tract infections in the community, the aim of the present study was to evaluate the prevalence of fimA, hly-A and papG virulence genes in Uropathogenic Escherichia coli in Iranian female adults with urinary tract infections. From March to October 2016, 200 urine samples were collected from 200 inpatient and outpatient women. The Escherichia coli bacteria was detected and isolated, using biochemical techniques and supplementary tests in the Microbiology Laboratory of Shahrekord University of Medical Sciences. Then virulence factors were identified by PCR method. The prevalence of papG, fimA and hlyA were 44, 74 and 26% of in inpatients and 52%, 76% and 28%, in outpatients, respectively. There was a significant correlation between papG and pyelonephritis in inpatients. There was no relationship between the frequency of papG, fimA and hlyA genes, and cystitis. The results of this study indicated that the fimA gene was the most frequent among the general public, and the hlyA gene was the least frequent and the papG gene was associated with pyelonephritis.

Genotypic analysis of Escherichia coli strains that cause urosepsis in the Aegean region.

The aim of this study was to characterize strains genotypically, to determine their phylogenetic relationships, to investigate the presence of the papG gene, and to compare their antibiotic susceptibility test results. Seventy pathogenic E. coli strains were isolated from both urine and blood cultures of patients with the preliminary diagnosis of urosepsis who were referred to the Ege University Faculty of Medicine, Bacteriology Laboratory of Medical Microbiology Department in İzmir. All of these strains were examined for the papG gene and phylogenetic groups with the multiplex polymerase chain reaction technique. Pulsed-field gel electrophoresis and multilocus sequence typing (MLST) were used for epidemiologic analysis. Phylogenetically, it was found that 16 belonged to group B2, 31 belonged to group D, 15 belonged to group A, and 7 belonged to group B1. One strain was not identified as belonging to a group. papG genes were found in 26 of 70 E. coli strains. Thirty urosepsis pathogenic E. coli strains were analyzed with MLST. Twenty-two strains were identified as new STs. These findings are extremely important for Turkey and these new 22 strains should be investigated in more detail because they are new and have the potential to lead to infections.

DETECTION FIMH AND PAPG GENES OF ESCHERICHIA COLI AND KLEBSIELLA PNEUMONIA ISOLATED FROM GALLSTONE , URINE STONE AND GASTROINTESTINAL CANAL BY POLYMERASE CHAIN REACTION (PCR) .

During this work twenty six isolates of Escherichia coli were collected (12 from gallstones , 10 from urin stones and 4 from gastrointestinal canal) and 14 isolates of Klebsiella pneumonia (4 from gallstones , 6 from urine stones and 4 from gastrointestinal canal) from Al-Ramadi Teaching Hospital. The resulte about Detection of fimH gene which are responsible for coding to Mannose sensitive fimbriae and three types of papG genes which are responsible for coding to Mannose resistance fimbriae showed (50-60)% of E. coli and (83.33%) of K. pneumoniae both of bacteria were isolated from urine stones only have fimH gene. E. coli isolates from gallston have papGI gene (16.67%) , papGII (50%) and papGIII gene (100%), While E. coli isolates from urine stone have papGII (20%) and papGIII (70%), While E. coli isolates from gastrointestinal canal have papGII (50%) and papGIII (25%), but K. pneumonia isolates didn,t possess any of three papG genes.

Role of K1 capsule antigen in cirrhotic patients with Escherichia coli spontaneous bacterial peritonitis in southern Taiwan

Spontaneous bacterial peritonitis (SBP) is one of the most serious complications in patients with cirrhosis. This study aimed to investigate the prevalence of SBP caused by Escherichia coli isolates with or without the K1 capsule antigen in cirrhotic patients and the outcome. From January 2004 to January 2012, a total of 54 and 41 E. coli strains derived from patients with SBP and intestinal perforation (IP), respectively, were included for comparison in this study. Bacterial characteristics including phylogenetic groups, K1 capsule antigen, and 14 virulence factor genetic determinants, as well as data regarding patient characteristics, clinical manifestations, and in-hospital deaths, were collected and analyzed. The prevalence of the K1 capsule antigen gene neuA was more common in SBP isolates compared to IP isolates (28 % vs. 10 %, p = 0.0385). Phylogenetic groups B2 and group D were dominant in E. coli isolates with and without the K1 capsule antigen, respectively. The prevalence of virulence factors genes papG II, ompT, and usp was higher in E. coli K1 strains. There were 26 deaths (48 %) during hospitalization. Presence of the K1 capsule antigen in E. coli isolates was significantly associated with in-hospital death in cirrhotic patients with SBP (42 % vs. 14 %, p = 0.0331). This study demonstrates a higher prevalence of the K1 capsule antigen in E. coli SBP compared to E. coli peritonitis caused by IP. There were significant associations between the K1 capsule antigen and in-hospital mortality and bacterial virulence in cirrhotic patients with E. coli SBP.

Characterization of uropathogenic Escherichia coli strains obtained from urology outpatient clinic of Ege Medical Faculty in İzmir

To identify the papG gene and its allelic variation in uropathogenic Escherichia coli (UPEC) strains isolated from patients with acute pyelonephritis and cystitis. Materials and methods: Seventy-five E. coli strains isolated from patients admitted to the University of Ege Medical Faculty urology outpatient clinic were isolated and identified phenotypically. All of these strains were examined for the papG gene and allelic distribution of this gene with the multiplex polymerase chain reaction technique. Results: papG genes were found in 24 of 75 E. coli strains. Of these 24 strains, 7 (29%) had papG class II only, 8 (33%) had class III only, and 9 (38%) had both class II and III. Phylogenetically, it was found that 31 belonged to group B2, 19 to group D, 20 to group A, and 5 to group B1. Serotyping was performed and the positivity was found to be 39%. When the antibiotic resistance profiles of the 75 strains were evaluated, 41 (55%) of them were found to be resistant to ampicillin, 35 (47%) to ciprofloxacin, and 35 (47%) to trimethoprim/sulfamethoxazole. In addition, 23 strains (31%) produced extended-spectrum beta-lactamase. Conclusion: In this study, the rate of papG-positive strains was found to be low. However, there is no consensus on the molecular definition of UPEC. Although the presence of the papG gene indicates that the strains are UPEC, absence of the papG gene does not suggest that the strains are not UPEC.

Identification and genetic characterization of an ethylene-dependent polygalacturonase from apricot fruit

During fruit ripening a loss of firmness occurs, which is a key factor limiting postharvest life. In apricot, Prunus armeniaca L., a wide range of fruit firmness at commercial maturity has been observed in different cultivars. Endopolygalacturonase (endoPG) activity has been reported to be associated with differences in firmness in many fruit species, but never in apricot. In this paper, we reported the identification of an apricot cDNA ( PaPG) coding for an endoPG-like protein with 393 amino acids. Protein sequence comparison with known polygalacturonases (PGs) revealed that multiple features as conserved domains and functional residues and a predicted signal peptide were present in PaPG. Moreover, a phylogenetic analysis of this and other plant PGs placed PaPG into a clade containing endoPGs expressed in fruit, abscission and dehiscence zones without a propeptide sequence, very close to PRF5 from peach ( Prunus persica L. Batsch). PaPG gene expression increased during postharvest storage of the fruit, correlating with fruit softening and ethylene release, and it responded to exogenous ethylene treatments. We localized the PaPG gene in apricot linkage group 4 after genetic mapping based on SNP analysis, in a position apparently syntenic to the PRF5 locus from peach. Results obtained offer genetic evidence supporting the hypothesis that PaPG and PRF5 are orthologous genes, and consequently position PaPG as a gene of interest for studies on fruit softening in apricot, and contribute to the development of molecular tools for breeding apricots with longer shelf life.

The effect of nitric oxide on adherence of P-fimbriated uropathogenic Escherichia coli to human renal epithelial cells

To examine the effect of nitric oxide (NO), an endogenous component of the host defence in urinary tract infection, on the adherence of P-fimbriated uropathogenic Escherichia coli (UPEC) to human renal epithelial cells. Two wild-type UPEC strains (AD110 and IA2) and the P-fimbriated recombinant strain HB101pPIL-75 were used. Bacteria were allowed to adhere to the human renal epithelial cell line A498 and attachment was evaluated in the absence or presence of the NO donor DETA/NONOate (1 mm). Total RNA was extracted from NO-exposed bacteria in static urine cultures, followed by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis of the papG gene that encodes the P-fimbriae adhesin PapG. Bacterial adherence to A498 cells was fimbriae-dependent and the ability to agglutinate human P(1) positive erythrocytes confirmed that the used strains were P-fimbriated. UPEC strains AD110 and IA2 attached by a mean of 8 bacteria/cell and 20 bacteria/cell, respectively. In the presence of DETA/NONOate, the attachment of AD110 and IA2 to A498 cells was significantly reduced by a mean (sem) of 34 (3.9)% and 45 (14)%, respectively. The expression of papG was decreased after DETA/NONOate exposure as shown by semiquantitative RT-PCR. NO disrupted functional adhesion of P-fimbriated UPEC to kidney epithelial cells, suggesting that NO-production from epithelial cells in the urinary tract may limit bacterial colonization at the mucosal surface. The reduced adherence may involve transcriptional effects of NO on papG expression, but further studies are needed to establish the underlying mechanisms.

Profiles of Virulence-associated Genes of Avian Pathogenic Escherichia coli Isolates from Chickens with Colibacillosis

The colibacillosis caused by avian pathogenic E. coli (APEC) is responsible for a significant loss of productivity and mortality in the poultry industry. The pathogenicity of these bacteria is based on the presence and expression of various virulence factors. In this study, the presence of the 19 virulence-associated genes in APEC was determined using PCR. Among the 118 E. coli isolates from the chickens with colibacillosis, all contained at least one of the 19 genes as approximately 95% of the isolates contained fimC. Interestingly, the clpG gene, which has not been detected in APEC previously, was detected in half of the isolates. The ColV plasmid-associated genes such as colV, tsh, iucC, iucD and iss genes were also detected in 57.6, 55.9, 50.0, 47.5, 47.5 and 41.5% of isolates, respectively. With regard to the fimbrial genes, the papA (14.4%), papC (14.4%) and papG genes (15.2%) were identified at relatively low rates, none of the isolates harbored afa8D, f17A or facA, and only 3 of the isolates (2.5%) contained eaeA. In this study, 94 isolates harbored two or more of the genes, and there were 43 different patterns of gene combination in the isolates. The most common pattern, which was found in 14.4% (17 isolates), was clpG-fimC-iutA-colV-tsh-iucC-iucD-irp2-fyuA-vat-iss. Overall, these results suggest that APEC strains in this area commonly contain multiple virulence factors and approximately half of the APEC strains contained the ColV plasmid-associated genes. Especially, colV and tsh were detected more than half of the isoaltes.

Occurrence of Pathogenicity Island IAPEC-O1Genes Among Escherichia coli Implicated in Avian Colibacillosis

Colibacillosis caused by avian pathogenic Escherichia coli (APEC) is a leading cause of economic loss to the poultry industry worldwide. The ability of APEC to cause disease is determined by certain virulence markers, some of which are located on pathogenicity islands (PAls). We recently described one such PAI in an APEC O1:K1 strain (APEC-O1). This PAI, termed PAI I(APEC-O1), carries the genes of the pap operon, a region similar to the tia invasion determinant of enterotoxigenic E coli; ireA, a gene that encodes an iron-responsive element; and a novel 1.5-kb region, ORF 54. Here, the occurrence of six selected loci of PAI I(APEC-O1) (papA, papC, papG, ireA, tia, and ORF 54) among APEC and fecal E. coli strains from apparently healthy chickens (avian commensal E. coli) was determined using polymerase chain reaction (PCR) techniques. None of the commensal E. coli was positive for all six traits, whereas 7.2% of the APEC isolates were positive for all the traits. Although there was no significant difference in the occurrence of ORF 54 among APEC and commensal E. coli, tia, ireA, papC, and papG genes were predominantly present in APEC rather than in avian commensal E. coli. papA was detected in only 6.3% of APEC, perhaps because of the presence of allelic variants of the gene. Additionally, the presence of all six traits was tested with PCR in APEC isolates collected in the 1980s, and these results were compared with those obtained with the APEC isolated in the 1990s. There was no significant difference in the occurrence of tia, ireA, papC, papG, and ORF 54 between APEC isolates collected during the different decades. However, papA was more frequently present in APEC from the 1980s than it was in APEC from the 1990s. Phylogenetic group of an isolate did not correlate with pathogenicity or the presence of PAI traits, except that more APEC of the low-pathogenicity group belonged to the phylogenetic group B1. However, PAI traits occurred more frequently in isolates belonging to the intermediate- and high-pathogenicity groups than in isolates of low pathogenicity.

Role of type 1 fimbria- and P fimbria-specific adherence in colonization of the neurogenic human bladder by Escherichia coli.

Recent clinical studies suggest that the deliberate colonization of the human bladder with a prototypic asymptomatic bacteriuria-associated bacterium, Escherichia coli 83972, may reduce the frequency of urinary tract infection in individuals with spinal cord injuries. However, the mechanism by which E. coli 83972 colonizes the bladder is unknown. We examined the role in bladder colonization of the E. coli 83972 genes papG and fimH, which respectively encode P and type 1 receptor-specific fimbrial adhesins. E. coli 83972 and isogenic papGDelta and papGDelta fimHDelta mutants of E. coli 83972 were compared for their capacities to colonize the neurogenic human bladder. Both strains were capable of stable colonization of the bladder. The results indicated that type 1 class-specific adherence and P class-specific adherence, while implicated as significant colonization factors in experiments that employed various animal model systems, were not required for colonization of the neurogenic bladder in human beings. The implications of these results with regard to the selection of potential vaccine antigens for the prevention of urinary tract infection are discussed.

The role of bacterial virulence and host factors in patients with Escherichia coli bacteremia who have acute cholangitis or upper urinary tract infection.

We studied the pathogenic role of host and Escherichia coli virulence factors in the development of E. coli bacteremia in patients with acute cholangitis (AC) or upper urinary tract infection (UTI). Isolates recovered from 75 adult patients consecutively admitted to the hospital with E. coli bacteremia caused by AC (n=24) or upper UTI (n=51) were evaluated, as were 30 fecal strains isolated from healthy control individuals. Virulence genes of E. coli were detected by polymerase chain reaction analysis, including papG genes (classes I-III), sfa/foc, fimH, afa, hlyA, cnf1, and iutA. Our results show that biliary tract obstruction and urinary tract obstruction are important host factors for the development of E. coli bacteremia in patients with AC and upper UTI, respectively. With regard to E. coli virulence factors, the papG class II gene might play a more important role in the development of E. coli bacteremia in patients with upper UTI than in those with AC.

Recurrent urinary tract infections in infancy: relapses or reinfections?

Seventeen infants with an index episode of pyelonephritis caused by Escherichia coli were monitored for 18 months for recurrent urinary tract infections (UTIs). All the infants had at least 1 recurrent UTI caused by the same pathogen. Twenty-six recurrent UTI episodes were recorded. The 40 E. coli strains available were analyzed by multiplex polymerase chain reaction for 3 alleles (classes I-III) of the papG gene and by pulsed-field gel electrophoresis (PFGE) after genomial digestion by XbaI. Of the 17 index strains, 12 (71%) carried the papG gene; 67% of these strains had class II alleles. In recurrent UTI isolates, the papG-positive E. coli appeared in 16 (70%) of 23 isolates. The proportion of all recurrent isolates available that represented a strain previously encountered (indistinguishable or highly similar in PFGE) in the same infant was 65%. Our results suggest that most recurrent UTIs in infants are endogenous relapses rather than reinfections caused by new organisms.

Distribution of papG alleles among uropathogenic Escherichia coli isolated from different species

The distribution of alleles I, II and III of the P adhesin gene papG among Escherichia coli isolated from urinary tract infections in humans, dogs and cats was studied by PCR. Allele I was present in 6% and 5% of the human and cat isolates. Allele II as such was present in 30% and 22%, or in association with allele III in 12% and 2% of the human and canine isolates, respectively. Allele III was present in 33% of the human strains and predominated largely over allele II in E. coli isolates from cystitis of animal origin (72% in dog and 95% in cat strains). The three different classes of the PapG adhesin have been suggested to play a role in host specificity, for example human versus canine specificity. Recent studies, however, showed papG III positive human and dog cystitis isolates to be largely indistinguishable. We found the Class II allele in animal isolates and detected for the first time in Europe the Class I allele in a different genetic background than the J96-like clonal group. Our findings show that uropathogenic E. coli isolates from different species can have the same papG alleles and thus may have zoonotic potential.

Genomic identity of pyelonephritogenic Escherichia coli isolated from blood, urine and faeces of children with urosepsis.

Chromosomal genotypes of Escherichia coli isolates from blood, urine and faeces of infants with urosepsis were studied to find possible clonality of the isolates. The isolates were analysed by PCR for class I, II and III alleles of the pyelonephritis-associated adhesin gene papG. The macrorestriction profiles of the papG-positive isolates were analysed by pulsed-field gel electrophoresis and their O serogroups were determined. Genetically identical E. coli isolates from the blood, urine and faeces of the same infant were found in 8 of 10 infants. This finding confirmed the results of previous phenotypic studies that the reservoir of pyelonephritogenic E. coli is indeed the colon.

P fimbriae, capsule and aerobactin characterize colonic resident Escherichia coli.

Resident and transient Escherichia coli strains from the colonic microflora of 13 Swedish schoolgirls were analysed for carriage of genes encoding a range of adhesins (P, type 1 and S fimbriae, Dr haemagglutinin and three varieties of the P fimbrial papG adhesin) and other virulence traits (K1 and K5 capsule, haemolysin and aerobactin) using multiplex PCR. Forty-four percent of the resident clones carried genes for P fimbriae, K1 or K5 capsule, and aerobactin, compared with only 3% of transient clones (P < 0.0001). The P-fimbriated clones most often had the class II variety of the P-fimbrial adhesin gene papG and this adhesin was significantly associated with persistence of a strain. S fimbriae and type 1 fimbriae were equally common in resident and transient strains. The results indicate that not only P fimbriae, but also, certain capsules and the ability to produce the siderophore aerobactin might contribute to persistence of E. coli in the large intestine.

Predominance of class II papG allele of Escherichia coli in pyelonephritis in infants with normal urinary tract anatomy.

P-fimbrial genotypes of Escherichia coli strains and their possible association with urinary tract abnormalities were studied in infants with pyelonephritis. A total of 153 urinary E. coli strains were analyzed by polymerase chain reaction for class I, II, and III alleles of the pyelonephritis-associated adhesin gene papG. Strains with any class II papG alleles were found significantly more often in infants with normal anatomy and function or in infants with clinically insignificant abnormalities than they were in infants with significant abnormalities (90 of 119 vs. 14 of 34 infants; P<. 001). On the other hand, strains without any papG alleles were found significantly more often in infants with major urinary tract abnormalities (11 of 34 vs. 17 of 119 infants; P=.016). Our genotypic findings indicate that, especially in infants with a normal urinary tract, infection is caused by more-virulent E. coli than is present in infants without a normal urinary tract. This virulence could be due to expression of pyelonephritogenic P fimbriae by an infecting E. coli strain.

Colonization with and acquisition of uropathogenic Escherichia coli as revealed by polymerase chain reaction-based detection.

The prevalence of colonization with uropathogenic Escherichia coli and their reservoirs and routes of acquisition are incompletely defined. To help clarify these issues, polymerase chain reaction (PCR)-based strain typing assays were used to evaluate the fecal and vaginal E. coli flora of 11 volunteers. PCR detected the virulence genes papG, aer, and cnf significantly more frequently in mixed intestinal samples than in the corresponding predominant strains, evidence that traditional methods are suboptimal for detecting colonization with uropathogens. For strain typing, repetitive-element PCR was as discriminating as pulsed-field gel electrophoresis and O:H serotyping but more convenient. Molecular epidemiologic analysis of subjects' E. coli suggested emergence of occult uropathogenic strains from within the host's own intestinal flora, strain sharing between household members, and de novo acquisition of (unshared) uropathogenic strains. These methods should facilitate the studies needed to clarify the relative contributions of these three pathways to the pathogenesis of urinary tract infection.