Urinary tract infection in Uruguayan children: Aetiology, antimicrobial resistance and uropathogenic Escherichia coli virulotyping

In house-development of a rapid immunochromatographic test for the detection of Escherichia coli in urine samples

Urinary tract infections (UTIs) are a common health concern. Urine culture is the "gold standard" for UTI diagnosis but takes 48h. Rapid methods like dipstick tests are used as point-of-care tests. However, their sensitivity and specificity are variable. In this work, a rapid immunochromatographic test (IT) for detecting Escherichia coli in urine was developed, and its performance was evaluated in urine samples from patients with suspected UTI. The "universal lateral flow assay kit" was employed using an E. coli capture antibody. One hundred and five (105) urine samples were analyzed using the IT, dipstick test, and urine culture. The sensitivity of the IT was 74.5%, specificity 88.9%, positive predictive value (PPV) 86.3%, and negative predictive value (NPV) 78.7%. The combination of the IT with the dipstick test increases sensitivity to 94.1%, specificity to 66.7%, PPV to 72.7%, and NPV to 92.3%. Using the IT for detecting E. coli in urine could be a valuable technique for UTI screening, showing better specificity and diagnostic precision but lower sensitivity than the dipstick test. Based on these results, we propose that the combined use of both screening techniques would allow a rapid and more precise diagnosis of UTI, rationalizing the indication for empirical antibiotics.

Distribution of phylogenetic groups, adhesin genes, biofilm formation, and antimicrobial resistance of uropathogenic Escherichia coli isolated from hospitalized patients in Thailand

Background

Urinary tract infections (UTIs) are the most common bacterial infections and are often caused by uropathogenic Escherichia coli (UPEC). We investigated the distribution of phylogenetic groups, adhesin genes, antimicrobial resistance, and biofilm formation in E. coli isolated from patients with UTIs.

Methods

In the present study, 208 UPEC isolated from Thai patients were classified into phylogenetic groups and adhesin genes were detected using multiplex PCR. Antimicrobial susceptibility testing was performed using agar disk diffusion. The Congo red agar method was used to determine the ability of the UPEC to form biofilm.

Results

The most prevalent UPEC strains in this study belonged to phylogenetic group B2 (58.7%), followed by group C (12.5%), group E (12.0%), and the other groups (16.8%). Among adhesin genes, the prevalence of fimH (91.8%) was highest, followed by pap (79.3%), sfa (12.0%), and afa (7.7%). The rates of resistance to fluoroquinolones, trimethoprim-sulfamethoxazole, and amoxicillin-clavulanate were  65%, 54.3%, and 36.5%, respectively. The presence of adhesin genes and antibiotic resistance were more frequent in groups B2 and C compared to the other groups. Of the 129 multidrug-resistant UPEC strains, 54% were biofilm producers. Our findings further indicated that biofilm production was significantly correlated with the pap adhesin gene (p ≤ 0.05).

Conclusion

These findings provide molecular epidemiologic data, antibiotic resistance profiles, and the potential for biofilm formation among UPEC strains that can inform further development of the appropriate prevention and control strategies for UTIs in this region.

Relationship between low serum vitamin D status and urinary tract infection in children: a case-control study

BACKGROUND

A link between vitamin D deficiency and susceptibility to bacterial and viral infections has recently been suggested.

AIM

To investigate a possible association between vitamin D deficiency and urinary tract infection (UTI).

METHODS

A case-control study was undertaken comprising 75 children aged 2-7 years with UTI (cases) compared with 75 healthy controls in terms of serum 25 hydroxyvitamin D [25(OH)D] levels. Serum 25(OH)D levels were measured using a chemiluminescence assay. For cases, dimercaptosuccinic acid (DMSA) renal scan was used as the gold standard to distinguish between acute lower UTI (cystitis) and acute pyelonephritis.

RESULTS

Median (IQR) 25(OH)D levels were lower in the UTI group [14.5 ng/mL (9.4-18.8)] than in the controls [27 ng/mL (22.4-39.0)] (p< 0.001). In addition, the prevalence of 25(OH)D levels <20 ng/mL was higher in the children with UTI than in the controls (68% vs 18%) (p< 0.001). There was a statistically significant difference between the cystitis and pyelonephritis groups in mean (SD) serum 25(OH)D levels-18.76 (9.35) ng/mL vs 13.94 (6.97) ng/mL, p< 0.05, respectively.

CONCLUSION

Low serum vitamin D is associated with UTI and supports the hypothesis that children with low vitamin D levels could be at greater risk of UTI.

Effect and Analysis of Bacterial Lysates for the Treatment of Recurrent Urinary Tract Infections in Adults

Urinary tract infection (UTI) is a relevant public health problem, economically and socially affecting the lives of patients. The increase of antimicrobial bacterial resistance significantly hinders the treatment of UTIs, raising the need to search for alternative therapies. Bacterial lysates (BL) obtained from Escherichia coli and other pathogens have been used to treat different infectious diseases with promising results. This work aims to evaluate the effect and composition of an autologous BL for the treatment and control of recurrent UTIs in adults. The results show remission in 70% of the patients within the first three months after the administration of BL, while the infection is maintained under control for 6-12 months. The analysis by liquid chromatography-mass spectrometry (LC-MS) of the BL fractions recognized by the sera of patients shows the presence of cytosolic proteins, fimbriae, OMPs, and LPS. Our study demonstrates that the autologous BL contributed to the treatment and control of recurrent UTIs in adults, and its composition shows that different surface components of E. coli are potential immunogens that could be used to create a polyvalent protective vaccine.

Snapshot of Phylogenetic Groups, Virulence, and Resistance Markers in Escherichia coli Uropathogenic Strains Isolated from Outpatients with Urinary Tract Infections in Bucharest, Romania

BACKGROUND

Urinary tract infections (UTIs) caused by Uropathogenic Escherichia coli (UPEC) are among the most common infections worldwide, including Romania. To the best of our knowledge, this is the first study performed on a significant number of community-acquired (CA) UPEC strains isolated from Romanian outpatients, aiming to evaluate and establish potential correlations among the phylogenetic groups (PG), resistance profiles, and the virulence factors (VF) genes of the CA-UPEC isolates.

MATERIALS/METHODS

The present study was performed on a total of 787 UPEC nonrepetitive isolates consecutively isolated during one month from outpatients with CA-UTIs, visiting one of the biggest laboratories in Bucharest, Romania, receiving patients from all over the country. The strains identification was performed by MALDI TOF and the susceptibility patterns were tested using Microscan according to CLSI guidelines. PCR assays were performed to detect the presence of different VFs (fimH gene encoding for type 1 fimbriae, afaBC for A fimbriae, sfaDE for S fimbriae, KpsMTII for capsule, hlyA for haemolysin A, hlyD for haemolysin D, and cnf-1 for tumor necrosis factor), the phylogenetic groups (PG) A, B1, B2, and D, and the extended spectrum beta-lactamases (ESBLs) genes.

RESULTS

The 787 CA-UPEC strains were isolated predominantly from female patients (90.95%) of >30 years (~74%). The resistance rates were 47.52% for ampicillin, 41.16% for tetracycline, 24.39% for cotrimoxazole, 19.18% for amoxicillin-clavulanic acid, 15.50% for cefazolin, 14.99% for ciprofloxacin, and 14.86% for levofloxacin; 35.19% of the investigated strains were MDR and 9.03% ESBL producers (from which 42.25% were positive for blaCTX-M, 38.02% for blaTEM, and 19.71% for blaSHV). FimH was the most frequent virulence gene (93.90%) followed by hlyD (44.34%); afaBC (38.24%); KpsMTII (32.65%); sfaDE (23.88%); hlyA (12.45%); and cnf-1 (7.75%). The distribution of the analyzed UPEC strains in phylogenetic groups was different for non-MDR and MDR strains. Overall, 35% of the strains belonged to the phylogenetic group B2 (harboring the yjaA gene); 27% to group B1 (confirmed by the presence of the TspE4C2 fragment); 16% to group D; and 22% to group A. The CA-UPEC strains included in PG B1 and PG B2 proved to be the most virulent ones, the number of strains carrying multiple VFs (>3) being significantly larger as compared to strains belonging to PG A and PG D) (p<0,0001). The presence of one or two ESBL genes was significantly associated (p =0.0024) with PGs A and D.

CONCLUSIONS

Our findings showed that the community UPEC strains circulating in Bucharest, Romania, belong predominantly to group B2 and >90% harbored the fimH gene. High MDR resistance rates were observed, as well as extended VF profiles, highlighting the importance of this type of studies for improving the epidemiological surveillance and the therapeutic or prophylactic management of the respective infections, in the context of antibiotic resistance emergence.

Fosfomycin tromethamine activity on biofilm and intracellular bacterial communities produced by uropathogenic Escherichia coli isolated from patients with urinary tract infection

Fosfomycin tromethamine (FT), an old antibiotic revived as a new strategy to overcome antibiotic resistance, is an excellent option for the treatment of lower urinary tract infection (UTI). During UTI, Escherichia coli produces biofilms and could invade the bladder epithelial cells, developing intracellular bacterial communities (IBC). The present work aimed to evaluate the activity of FT on biofilms and IBC from clinical isolates of E. coli. A total of 38 E. coli clinical UTI isolates previously characterized as biofilm and IBC producers were studied. FT susceptibility was evaluated and its activity on 48 h biofilm was determined by microtiter plate-based biofilm assay comparing three different antibiotic concentrations. Two UPEC strains were selected to evaluate FT activity on IBC in vitro using T24 bladder cells. The survival percentage of intracellular bacteria after 24 h exposure to FT was calculated and compared to the percentage of intracellular bacteria without antibiotic. All the strains were susceptible to FT. FT produced a significant reduction of biofilms at the three concentrations tested, compared to the control. However, no statistically effect on IBC was observed after 24 h of fosfomycin exposure in cell culture. FT is a good option for bacterial biofilm reduction within UTI. However, it does not affect IBC.