Comparison of phenotypic and genetic traits of ESBL-producing UPEC strains causing recurrent or single episode UTI in postmenopausal women
Abstract Background Recurrent urinary tract infections (rUTIs) occur in over 20% of patients, with postmenopausal women (over 50 years old) carrying the highest risk for recurrence compared to younger women. Virulence factors such as type 1 fimbriae adhesin FimH, the outer membrane protease OmpT, an...
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BMC
2025-02-01
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| Series: | Annals of Clinical Microbiology and Antimicrobials |
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| Online Access: | https://doi.org/10.1186/s12941-025-00779-7 |
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| author | Michelle Kalu Peter Jorth Annie Wong-Beringer |
| author_facet | Michelle Kalu Peter Jorth Annie Wong-Beringer |
| author_sort | Michelle Kalu |
| collection | DOAJ |
| description | Abstract Background Recurrent urinary tract infections (rUTIs) occur in over 20% of patients, with postmenopausal women (over 50 years old) carrying the highest risk for recurrence compared to younger women. Virulence factors such as type 1 fimbriae adhesin FimH, the outer membrane protease OmpT, and the secreted pore-forming toxin α-hemolysin (HlyA) have been shown to support the formation of intracellular bacterial communities (IBCs) within bladder epithelial cells (BECs), facilitating persistence. This study aims to characterize the virulence expression and intracellular persistence of ESBL-producing uropathogenic E. coli (E-UPEC) strains isolated from postmenopausal women with recurrent or single episode infections. Methods Study strains included 72 E-UPEC strains collected from patients (36 recurrent; 36 single episode) with a confirmed UTI diagnosis and control UPEC strains (CFT073 and UTI89). Patient demographics and clinical course were collected. Presence of hlyA, ompT, and fimH genes were confirmed by colony PCR, and qRT-PCR was performed using extracted RNA from a subset of 18 strains (12 recurrent; 6 single episode) grown in Luria-Bertani media and isolated from infected BECs to characterize gene expression. Bladder cell line 5637 was infected with study strains at MOI 15 for 2 h, treated with amikacin for 2 h to remove extracellular bacteria, then lysed to enumerate intracellular CFU counts. Results No differences in clinical characteristics between patient groups were observed. Overall prevalence of fimH, ompT, and hlyA was 99% (71/72), 82% (59/72), and 26% (19/72) respectively; presence of all three genes did not differ between recurrent and single-episode strains. Notably, all recurrent strains had significantly more intracellular CFUs compared to single episode strains (median 16,248 CFU/mL vs. 4,118 CFU/mL, p = 0.018). Intracellular expression ompT was significantly increased (p = 0.0312) in the recurrent group compared to LB media, while fimH was significantly decreased (p = 0.0365) in the single episode group compared to expression in LB media. Conclusion Our findings indicate strain-specific ability to persist inside BECs with the recurrent strains exhibiting increased ompT expression inside BECs and higher intracellular bacterial burden compared to strains causing single episode UTI. These results emphasize the potential microbial contributions to recurrence in postmenopausal women and warrant future investigations on the impact of antibiotic therapy and host response on IBC-supportive UPEC virulence. |
| format | Article |
| id | doaj-art-df56d605d2df48c9add3f41b6beecef5 |
| institution | Kabale University |
| issn | 1476-0711 |
| language | English |
| publishDate | 2025-02-01 |
| publisher | BMC |
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| series | Annals of Clinical Microbiology and Antimicrobials |
| spelling | doaj-art-df56d605d2df48c9add3f41b6beecef52025-02-09T12:16:44ZengBMCAnnals of Clinical Microbiology and Antimicrobials1476-07112025-02-0124111110.1186/s12941-025-00779-7Comparison of phenotypic and genetic traits of ESBL-producing UPEC strains causing recurrent or single episode UTI in postmenopausal womenMichelle Kalu0Peter Jorth1Annie Wong-Beringer2Department of Clinical Pharmacy, University of Southern California Alfred E. Mann School of Pharmacy and Pharmaceutical SciencesDepartment of Pathology and Laboratory Medicine, Cedars-Sinai Medical CenterDepartment of Clinical Pharmacy, University of Southern California Alfred E. Mann School of Pharmacy and Pharmaceutical SciencesAbstract Background Recurrent urinary tract infections (rUTIs) occur in over 20% of patients, with postmenopausal women (over 50 years old) carrying the highest risk for recurrence compared to younger women. Virulence factors such as type 1 fimbriae adhesin FimH, the outer membrane protease OmpT, and the secreted pore-forming toxin α-hemolysin (HlyA) have been shown to support the formation of intracellular bacterial communities (IBCs) within bladder epithelial cells (BECs), facilitating persistence. This study aims to characterize the virulence expression and intracellular persistence of ESBL-producing uropathogenic E. coli (E-UPEC) strains isolated from postmenopausal women with recurrent or single episode infections. Methods Study strains included 72 E-UPEC strains collected from patients (36 recurrent; 36 single episode) with a confirmed UTI diagnosis and control UPEC strains (CFT073 and UTI89). Patient demographics and clinical course were collected. Presence of hlyA, ompT, and fimH genes were confirmed by colony PCR, and qRT-PCR was performed using extracted RNA from a subset of 18 strains (12 recurrent; 6 single episode) grown in Luria-Bertani media and isolated from infected BECs to characterize gene expression. Bladder cell line 5637 was infected with study strains at MOI 15 for 2 h, treated with amikacin for 2 h to remove extracellular bacteria, then lysed to enumerate intracellular CFU counts. Results No differences in clinical characteristics between patient groups were observed. Overall prevalence of fimH, ompT, and hlyA was 99% (71/72), 82% (59/72), and 26% (19/72) respectively; presence of all three genes did not differ between recurrent and single-episode strains. Notably, all recurrent strains had significantly more intracellular CFUs compared to single episode strains (median 16,248 CFU/mL vs. 4,118 CFU/mL, p = 0.018). Intracellular expression ompT was significantly increased (p = 0.0312) in the recurrent group compared to LB media, while fimH was significantly decreased (p = 0.0365) in the single episode group compared to expression in LB media. Conclusion Our findings indicate strain-specific ability to persist inside BECs with the recurrent strains exhibiting increased ompT expression inside BECs and higher intracellular bacterial burden compared to strains causing single episode UTI. These results emphasize the potential microbial contributions to recurrence in postmenopausal women and warrant future investigations on the impact of antibiotic therapy and host response on IBC-supportive UPEC virulence.https://doi.org/10.1186/s12941-025-00779-7Recurrent UTIsUPECPostmenopausal womenIntracellular bacterial communities |
| spellingShingle | Michelle Kalu Peter Jorth Annie Wong-Beringer Comparison of phenotypic and genetic traits of ESBL-producing UPEC strains causing recurrent or single episode UTI in postmenopausal women Annals of Clinical Microbiology and Antimicrobials Recurrent UTIs UPEC Postmenopausal women Intracellular bacterial communities |
| title | Comparison of phenotypic and genetic traits of ESBL-producing UPEC strains causing recurrent or single episode UTI in postmenopausal women |
| title_full | Comparison of phenotypic and genetic traits of ESBL-producing UPEC strains causing recurrent or single episode UTI in postmenopausal women |
| title_fullStr | Comparison of phenotypic and genetic traits of ESBL-producing UPEC strains causing recurrent or single episode UTI in postmenopausal women |
| title_full_unstemmed | Comparison of phenotypic and genetic traits of ESBL-producing UPEC strains causing recurrent or single episode UTI in postmenopausal women |
| title_short | Comparison of phenotypic and genetic traits of ESBL-producing UPEC strains causing recurrent or single episode UTI in postmenopausal women |
| title_sort | comparison of phenotypic and genetic traits of esbl producing upec strains causing recurrent or single episode uti in postmenopausal women |
| topic | Recurrent UTIs UPEC Postmenopausal women Intracellular bacterial communities |
| url | https://doi.org/10.1186/s12941-025-00779-7 |
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