Study of virulence factors of uropathogenic Escherichia coli and its antibiotic susceptibility pattern

Genome characterization of a multi-drug resistant Escherichia coli strain, L1PEag1, isolated from commercial cape gooseberry fruits (Physalis peruviana L.)

Introduction

Foodborne infections, which are frequently linked to bacterial contamination, are a serious concern to public health on a global scale. Whether agricultural farming practices help spread genes linked to antibiotic resistance in bacteria associated with humans or animals is a controversial question.

Methods

This study applied a long-read Oxford Nanopore MinION-based sequencing to obtain the complete genome sequence of a multi-drug resistant Escherichia coli strain (L1PEag1), isolated from commercial cape gooseberry fruits (Physalis peruviana L.) in Ecuador. Using different genome analysis tools, the serotype, Multi Locus Sequence Typing (MLST), virulence genes, and antimicrobial resistance (AMR) genes of the L1PEag1 isolate were determined. Additionally, in vitro assays were performed to demonstrate functional genes.

Results

The complete genome sequence of the L1PEag1 isolate was assembled into a circular chromosome of 4825.722 Kbp and one plasmid of 3.561 Kbp. The L1PEag1 isolate belongs to the B2 phylogroup, sequence type ST1170, and O1:H4 serotype based on in silico genome analysis. The genome contains 4,473 genes, 88 tRNA, 8 5S rRNA, 7 16S rRNA, and 7 23S rRNA. The average GC content is 50.58%. The specific annotation consisted of 4,439 and 3,723 genes annotated with KEEG and COG respectively, 3 intact prophage regions, 23 genomic islands (GIs), and 4 insertion sequences (ISs) of the ISAs1 and IS630 families. The L1PEag1 isolate carries 25 virulence genes, and 4 perfect and 51 strict antibiotic resistant gene (ARG) regions based on VirulenceFinder and RGI annotation. Besides, the in vitro antibiotic profile indicated resistance to kanamycin (K30), azithromycin (AZM15), clindamycin (DA2), novobiocin (NV30), amikacin (AMK30), and other antibiotics. The L1PEag1 isolate was predicted as a human pathogen, matching 464 protein families (0.934 likelihood).

Conclusion

Our work emphasizes the necessity of monitoring environmental antibiotic resistance, particularly in commercial settings to contribute to develop early mitigation techniques for dealing with resistance diffusion.

Presence of fimH and iss type 1, 2 and 3 genes in uropathogenic Escherichia coli isolates recovered from an apex medical institute in North India

PURPOSE

To detect the presence of fimH and iss type 1, 2 and 3 genes in uropathogenic Escherichia coli (UPEC) isolates recovered from patients coming to the out patient department (OPD) of our hospital.

METHODS

E. coli isolates recovered from patients who had symptoms of urinary tract infection (UTI) were processed for the presence of fimH and iss genes. DNA was extracted using an in house method after which conventional PCR using forward and reverse primers targeting the four genes was carried out. The amplified products were electrophoresed and visualized in a gel documentation imager. Relevant demographic details of the patients were recorded on a pre-designed pro-forma and antimicrobial susceptibility testing of the isolates was done by disc diffusion method.

RESULTS

fimH was present in 87.5% of UPEC isolates whereas iss type 1 was seen in 7.3%, type 2 in 4.2% and iss type 3 in 71.9% isolates. Age of the patients ranged from 3 months to 82 ​yrs (mean 43.5 SD ​± ​18.20). UTI was more common in females (60.2%) as compared to males patients (39.8%). Dysuria (66.7%) was the most common symptom in the studied subjects and diabetes mellitus (42.6%) the most common co-morbidity. A total of 56.5% patients gave a history of prior antibiotic intake. The UPEC isolates were resistant to most of the antibiotics tested. However all the isolates were sensitive to polymyxin B and colistin. Fosfomycin resistance was seen in 9.5% of the UPEC isolates harbouring fimH gene.

CONCLUSION

This is the first study that highlights the presence of iss type 3 gene in UPEC isolates along with the fimH and iss type 1 and 2 genes. The results of this study can serve as a stepping stone for future in depth research into the significance of the iss genes in causing UTI.

Study of antibiotic resistance and virulence genes in Escherichia coli isolated from urinary tract infection patients in Tanta University Hospitals

This study aimed to investigate the prevalence of antibiotic resistance genes CTX-M and Qnr, as well as the virulence genes HlyA, Pap, CNF1, and Afa, in uropathogenic Escherichia coli (UPEC) isolates from the Egyptian population. In this cross-sectional study, a total of 50 E. coli isolates were collected from urine samples from patients with urinary tract infections (UTIs) admitted to Tanta University Hospital from December 2020 to November 2021. The isolates were cultured, identified, and tested for antibiotic susceptibility by the disc diffusion method. The CTX-M, Qnr (QnrA, B, and S), Pap, CNF1, HlyA, and Afa genes were detected by polymerase chain reaction in UPEC isolates. The Pap, CNF1, HlyA, and Afa genes were found to be positive in 18%, 12%, 10%, and 2% of the isolates, respectively. In addition, CTX-M and QnrS were found to be positive in 44% and 8% of the isolates, while QnrA and B were not detected. Furthermore, positive Pap, CNF1, and HlyA genes were significantly associated with both upper and lower UTIs, increased frequency, urgency, and dysuria, and complicated UTIs, as well as pyuria over 100 white blood cells per high-power field. In conclusion, the prevalence of virulence and antibiotic resistance genes varies by population. At our hospital, the Pap gene is the most prevalent virulence gene and was strongly associated with complicated UTIs, while the CTX-M and QnrS genes were the most prevalent and related to antibiotic resistance. Our findings, however, should be interpreted with caution due to the small sample size.

Virulence-associated genes analysis of carbapenemase-producing Escherichia coli isolates

Carbapenem-resistant Escherichia coli has emerged as a major public health issue across the world. This study was aimed to determine the virulence content and phylogenetic groups of carbapenemase-producing E. coli isolates in southwest Iran. One hundred and fifty-two non-duplicate E. coli isolates were collected from various clinical samples. Antibiotic susceptibility and minimum inhibitory concentrations (MIC) were determined according to the Clinical and Laboratory Standards Institute (CLSI) guidelines by Kirby-Bauer disc diffusion and agar dilution methods. Phenotypic screening of carbapenemase enzymes was performed by modified Hodge test (MHT). Detection of carbapenemase genes, phylogenetic groups, and virulence-associated genes were also performed by the PCR assay. The highest and lowest resistance rates were observed against mezlocillin (70.4%) and doripenem (13.1%), respectively. Out of 28 isolates that were resistant to carbapenem antibiotics, 12 (7.9%) strains were phenotypically carbapenemase producers. The bla_OXA-48 was the predominant carbapenemase gene, detected in 58.3% of isolates, followed by bla_IMP (41.7%) and bla_NDM (8.3%). None of the isolates harbored bla_VIM and bla_KPC genes. Among the twelve carbapenemase-producing strains, urinary isolates were mostly classified into B2 (41.7%) and D (25%) phylogenetic groups, while other clinical isolates belonged to B1 (25%) and A (8.3%) groups. The frequency of virulence-associated genes was also investigated in all isolates and ranged from 6.6% for hly to 75% for fimA. The emergence of carbapenemase-producing strains is a growing concern to public health. Therefore, the proper implementation of monitoring programs is crucial for limiting their dissemination.

Uropathogenic Escherichia coli virulence characteristics and antimicrobial resistance amongst pediatric urinary tract infections

Uropathogenic Escherichia coli (UPEC) harbors virulence factors responsible for bacterial adhesion and invasion. In addition, the bacterium is accountable for the occurrence of pediatric urinary tract infections globally and is becoming problematic due to the emergence of antimicrobial resistance. The current research investigated UPEC prevalence, virulence characteristics, and antimicrobial resistance in pediatric urinary tract infection (UTI). 200 urine specimens were taken from hospitalized pediatric patients who suffered from UTIs. E. coli was recovered from urine specimens using the microbial culture. Disc diffusion method was used to assess antimicrobial resistance and polymerase chain reaction (PCR) to assess the virulence factors distribution amongst the UPEC bacteria. Seventy-five out of 250 (30.00%) urine samples were positive for the UPEC bacteria. The UPEC prevalence amongst pediatric patients was 25.83% and 33.84%, respectively. UPEC bacteria harbored the maximum resistance toward gentamicin (45.33%), ampicillin (44.00%), and ciprofloxacin (40.00%). Cytotoxic necrotizing factor 1 (Cnf1) (53.33%) and pyelonephritis-associated pil (pap) (42.66%) were the most frequently identified virulence factors amongst the UPEC bacteria. The high prevalence of UPEC isolates harboring antimicrobial resistance and virulence factors suggest that diseases caused by them need more expansive healthcare monitoring with essential demand for novel antimicrobials.

In-vitro Investigation of Antibiotics Efficacy Against Uropathogenic Escherichia coli Biofilms and Antibiotic Induced Biofilm Formation at Sub-Minimum Inhibitory Concentration of Ciprofloxacin

BACKGROUND

Community-acquired urinary tract infections are associated with significant morbidity, and uropathogenic Escherichia coli (UPEC) alone causes 90% of urinary tract infections. This bacterium retains a diverse armament of virulence factors including fimbria, hemolysins, and siderophores production. In a post invasion scenario, formation of intracellular communities mimic biofilm-like characteristics and are linked to recurrent urinary tract infections. We investigated the effects of different frontline antibiotics on the formation, inhibition, and eradication of biofilms of virulent UPEC strains.

MATERIALS AND METHODS

A total of 155 UPEC strains were scrutinized for various virulence factors including gelatinase, cell surface hydrophobicity, hemagglutination, and serum bactericidal activity. Biofilm formation was confirmed by three different methods: Congo red agar, test tube, and tissue culture plate method. Biofilm inhibition and eradication assays were performed according to the standard protocols. Topographical analysis of biofilms was done by scanning electronic microscopy (SEM).

RESULTS

Out of 155 strains, 113 (73%) were strong biofilm formesr, while 37 (24%) produced biofilms at moderate level. Significant differences were observed between MICs of planktonic cells (MIC-p) and MICs of UPEC biofilms (MIC-b). Among tested frontline antibiotics, levofloxacin successfully inhibited biofilms at a concentration of 32 µg/mL, while trimethoprim eradicated biofilms at higher concentrations (512-1024 µg/mL). Ciprofloxacin treatment at sub-MIC level significantly enhanced biofilm formation (P<0.05).

CONCLUSION

The majority of UPEC strains are strong biofilm formers and show higher tolerance towards frontline antibiotics in biofilm form. We observed significant inhibitory effects of levofloxacin (32 µg/mL) on UPEC biofilms, while treatment with sub-minimal concentrations of ciprofloxacin significantly enhanced biofilm formation. Out of all tested antibiotics, trimethoprim (512-1024 µg/mL) eradicated UPEC biofilms.

Virulence factors of uropathogenic Escherichia coli (UPEC) and correlation with antimicrobial resistance

Background

Escherichia coli has found to be the predominant uropathogen (50–90%) in uncomplicated, community acquired urinary tract infection (UTI). Uropathogenic Escherichia coli (UPEC) express a multitude of virulence factors, which enable the bacteria to establish UTI. The objective of this study was to evaluate the presence of different phenotypic virulence markers in UPEC isolates and determine their correlation with antibiotic resistance pattern.

Results

Out of 105 patients, 56 (53%) were females and 49 (47%) were males. The age of the patients in the study ranged from 18 years to 87 years and majority of the patients belonged to the age group 20–29 years. Virulence factor was observed in 65% (n = 69) of UPEC and 20% (n = 22) of control isolates (P = 0.0001). Haemolysin production was observed in 34(32.3%) of uroisolates and 12 (11.4%) of control strain. Similarly, 62% of UPEC and 1% of control produced biofilm (P = 0.0001). The expression of Mannose-resistant hemagglutinin (MRHA) and mannose-sensitive hemagglutinin (MSHA) in uroisolates were 52.3% (n = 55) and 5.7% (n = 6) respectively, whereas in faecal isolates, 8.5% (n = 9) expressed MRHA and none produced MSHA. Antimicrobial resistance showed a high degree of resistance towards ampicillin, cotrimoxazole and norfloxacin. The resistance was observed in significant higher degree in biofilm formers as compared to non-formers. MDR and ESBL was observed in 51 and 46% of test strains and 9 and 7.6% of control strains (P = 0.0001).

Conclusion

A significant association between virulence factors of UPEC and antimicrobial resistance in UPEC was present. Routine testing of these factors and co-relation with AMR is recommended. These findings will certainly help understand the pathogenicity and proper management of UTI patients, thus decreasing the improper use of antibiotics.

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

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 (≥10⁵ 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.

Antibiotic Resistance, RAPD- PCR Typing of Multiple Drug Resistant Strains of Escherichia Coli From Urinary Tract Infection (UTI)

INTRODUCTION

Global spreading of multidrug resistant strains of Escherichia coli is responsible for Urinary Tract Infection (UTI) which is a major health problem in of concern. Among the gram negative bacteria, the major contributors for UTI belongs to the family Enterobacteriaceae, which includes E. coli, Klebsiella, Citrobacter and Proteus. However, E. coli accounts for the major cause of Urinary tract infections (UTIs) and accounts for 75% to 90% of UTI isolates.

AIM

The main aim of this study is to analyse the phylogenetic grouping of clinical isolates of UTI E. coli.

MATERIALS AND METHODS

In this study nearly 58 E. coli strains were isolated and confirmed through microbiological, biochemical characterization. The urine samples were collected from outpatients having symptoms of UTI, irrespective of age and sex in Tamil Nadu, India. The isolates were subjected to analyse for ESBL and AmpC β-lactamase production. To understand its genetic correlation, molecular typing was carried out using RAPD-PCR method.

RESULTS

Here we noted phenotypically twenty seven isolates were positive for ESBL and seven for AmpC β-lactamase production. However, among the ESBL isolates higher sensitivity was noted for Nitrofurantoin and Cefoxitin. It is worth to note that the prevalence of UTIs was more common among female and elderly male. Phylogenetic grouping revealed the presence of 24 isolates belonged to B2 group followed by 19 isolates to group A, eight isolates to group B1 and Seven isolates to group D.

CONCLUSION

Phenotypically most of the strains were positive for ESBL and showed high sensitivity for Nitrofurantoin and cefoxitin.

A study on the aac-(61)-lb-cr gene prevalence among ciprofloxacin-resistant strains of uropathogenic Enterobacteriaceae

INTRODUCTION

Urinary tract infections (UTIs) are very common. Indiscriminate use of antibiotics has led to the development of resistance to most of the commonly used antibiotics including quinolones.

AIM

This study aimed to find out the prevalence of ciprofloxacin resistance among the uropathogenic Enterobacteriaceae, to determine the virulence factors of these isolates, and to detect the aac-(6¹)-lb-cr gene among those isolates with minimal inhibitory concentrations (MICs) of ciprofloxacin >256 mcg/ml.

MATERIALS AND METHODS

Urine samples reaching the microbiology laboratory were processed, pathogens belonging to the Enterobacteriaceae family were isolated from those with significant bacteriuria, and antibiotic sensitivity testing was performed according to the CLSI guidelines. MIC of ciprofloxacin for the isolates resistant to ciprofloxacin was determined by using the E-test, and virulence factors such as hemagglutination, hemolysis, and mucoid colonies were analyzed. aac-(6¹)-lb-cr gene was analyzed by polymerase chain reaction for those isolates with MIC > 256 mcg/ml.

RESULTS

Escherichia coli was the most common isolate (62%) with the highest ciprofloxacin resistance (68%). Fourteen percent of them had MIC > 256 mcg/ml and all of these isolates harbored the aac-(6¹)-lb-cr gene.

CONCLUSION

Plasmid-mediated drug resistance can rapidly spread and lead to selection of drug-resistant mutants if not controlled.