Characterization of Extended-Spectrum β-Lactamase-Producing Uropathogenic Escherichia coli Among Iranian Kidney Transplant Patients

Antibiotic resistance and virulence patterns of O25 and O16 serogroups in uropathogenic Escherichia coli

OBJECTIVE

This study investigates antibiotic resistance patterns, virulence factors, and phylogenetic groups of O25 and O16 serogroups in uropathogenic Escherichia coli (UPEC) isolates from kidney transplant recipients (KTPs) and non-KTPs. The presence of serogroups O25 and O16, resistance genes (e.g., blaCTX-M, blaTEM), and virulence factors (e.g., fimH, PAI) were determined using PCR. Phylogenetic groups were identified via quadruplex PCR, and genetic diversity was assessed using ERIC-PCR.

RESULTS

A total of 111 E. coli isolates were examined in the present study. The O-serotyping results indicated that 18% and 3.6% of isolates were positive for O25 and O16 serogroup, respectively. In serogroup O25, the highest resistance rates were observed for nalidixic acid and cotrimoxazole, whereas in serogroup O16, the highest resistance rates were against cotrimoxazole and ampicillin-sulbactam. ESBL production was identified in 30% of O25 and 25% of O16 isolates. O25 isolates belonged to phylogenetic group B2, whereas O16 isolates were grouped in B1. ERIC-PCR revealed significant genetic diversity among isolates. The O25 serogroup is prevalent and closely associated with high antibiotic resistance and virulence, suggesting its critical role in UTI pathogenesis in transplant patients. These findings underscore the importance of monitoring resistance patterns and developing targeted therapeutic and preventive strategies for managing UPEC infections.

Prevalence of plasmid-mediated quinolone resistance genes in extended-spectrum beta-lactamase producing Klebsiella pneumoniae isolates in northern Iran

Plasmid-mediated quinolone resistance (PMQR) in extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae (K. pneumoniae) contributes to treatment failures, extended hospital stays, and increased mortality percentages. We aimed to determine the prevalence of PMQR genes in ESBL-producing K. pneumoniae isolates from clinical samples in Babol, North of Iran region. This is the first study in this region to investigate this specific association. A total of 95 K. pneumoniae isolates were obtained from hospitalized patients with various clinical infections during March 2022 to February 2023. Disk diffusion and Combination disk method were performed to identification of antimicrobial resistance profiles and ESBL-producing strains. The presence of ESBL and PMQR genes among K. pneumoniae isolates was assessed using polymerase chain reaction (PCR) method. Of the isolates, 68 (71.57 %) were considered as ESBL-producers. The bla TEM, bla SHV and bla CTX-M genes were detected in 74.73 %, 57.89 %, and 41.05 % of K. pneumoniae isolates, respectively. Among the PMQR encoding genes, the highest and lowest frequency was associated to qepA (67.3 %) and qnrA (4.2 %), respectively. The frequency of qnrA, qnrB, qnrS, acc (6')-Ib-cr, qepA, oqxA, and oqxB genes in 26 MDR-Kp isolates was 11.53 % (n; 3), 69.23 % (n; 18), 65.38 % (n; 17), 73.07 % (n; 19), 80.76 % (n; 21), 84.61 % (n; 22), and 76.92 % (n; 20), respectively. Our result revealed of the 68 ESBL gene-positive isolates, 60 (88.23 %) were positive for the PMQR gene. The co-occurrence of these genes within resistant isolates suggests potential linkage on mobile genetic elements such as plasmids. These findings highlight the significant burden of PMQR determinants in ESBL-producing K. pneumoniae and underscore the urgent need for effective control measures. Implementing robust antimicrobial stewardship programs and strengthening drug-resistance surveillance and control protocols are crucial to prevent the spread of resistant isolates.

Whole genome sequencing of uropathogenic E. coli from Ireland reveals diverse resistance mechanisms and strong correlation with phenotypic (EUCAST) susceptibility testing

Urinary tract infections (UTI) caused by uropathogenic Escherichia coli (UPEC) pose a global health concern. Resistance mechanisms, including genetic mutations in antimicrobial target genes, efflux pumps, and drug deactivating enzymes, hinder clinical treatment. These resistance factors often spread through mobile genetic elements. Molecular techniques like whole genome sequencing (WGS), multilocus sequence typing (MLST), and phylotyping help decode bacterial genomes and categorise resistance genes. In this study, we analysed 57 UPEC isolates from different UTI patients following EUCAST guidelines. A selection of 17 representative strains underwent WGS, phylotyping, MLST, and comparative analysis to connect laboratory susceptibility data with predictive genomics based on key resistance genes and chromosomal mutations in antimicrobial targets. Trimethoprim resistance consistently correlated with dfr genes, with six different alleles detected among the isolates. These dfr genes often coexisted with class 1 integrons, with the most common gene cassette combining dfr and aadA. Furthermore, 52.9% of isolates harboured the blaTem-1 gene, rendering resistance to ampicillin and amoxicillin. Ciprofloxacin-resistant strains exhibited mutations in GyrA, GyrB and ParC, plasmid-mediated quinolone resistance genes (qnrb10), and aac(6')-Ib-cr5. Nitrofurantoin resistance in one isolate stemmed from a four amino acid deletion in NfsB. These findings illustrate the varied strategies employed by UPEC to resist antibiotics and the correlation between clinical susceptibility testing and molecular determinants. As molecular testing gains prominence in clinical applications, understanding key resistance determinants becomes crucial for accurate susceptibility testing and guiding effective antimicrobial therapy.

Molecular characterization of ESBL-producing uropathogenic Escherichia coli isolates among kidney transplant patients: Emergence and spread of B2-ST131 clone type

This study was conducted to identify the distribution of virulence determinants in uropathogenic Escherichia coli (UPEC) isolates obtained from kidney transplant (KTP) and non-transplant patients (non-KTP) with urinary tract infections (UTI). Additionally, the (GTG)5 fingerprinting technique was used to investigate the genetic diversity of Extended-Spectrum B-Lactamase (ESBL)-positive isolates. In this case-control study, 111 urine isolates were obtained from non-KTPs and KTPs, respectively. The presence of genetic markers encoding adhesion proteins, toxins and major E. coli phylogroups was assessed through PCR amplification. Molecular typing of ESBL-positive UPEC strains was performed using (GTG)5 fingerprinting and Multilocus sequence typing (MLST) techniques. Overall, 65 and 46 UPEC isolates were obtained from non-KTPs and KTPs, respectively. Among the studied isolates, traT (85.6%) gene was the most frequently observed virulence gene, followed by kpsMT (49.5%). Using the 80% cut-off point, all the 35 UPEC isolates were classified into four major clusters, namely A, B, C, and D. The majority of the Sequence Type (ST) 131 isolates belonged to cluster A. Additionally, three ST1193 isolates belonged to cluster A and phylogroup B2. Moreover, ST38, ST131 and ST10 were in different cluster. In general, we observed significant differences in the papA, ompT, sat, and vat genes between KTPs and non-KTPs. Furthermore, since all the isolates carried one or more virulence factors (VFs), these findings are concerning in the context of managing UTIs caused by the UPEC strain. Additionally, the distribution of ST and Clonal Complex (CC) among isolates in the main clusters revealed significant differences between MLST and (GTG)5 fingerprinting analysis.

Phylogenetic analysis, biofilm formation, antimicrobial resistance and relationship between these characteristics in Uropathogenic Escherichia coli

BACKGROUND

In the present study, we examine the prevalence of phylogenetic groups, O-serogroups, adhesin genes, antimicrobial resistance, the level of gene expression associated with biofilm formation, and the presence of extended-spectrum beta-lactamase (ESBL) in UPEC strains isolated from both pediatric and adult patients.

METHODS

In this cross-sectional study, 156 UPEC isolates were collected from UTI patients. ESBL-producing isolates were detected using the double-disc synergy (DDS) method, and biofilm formation was assessed through a microplate assay. The presence of O-serogroups, adhesion factors and resistance genes, including ESBLs and PMQR genes, was detected by PCR, and isolates were categorized into phylogenetic groups using multiplex PCR. Additionally, the quantitative real-time PCR method was also used to determine the expression level of genes related to biofilm.

RESULTS

During the study period, 50.6% (79/156) of the samples were obtained from children, and 49.4% (77/156) were from adults. The highest rate of resistance was to NA (91.7%), while FM (10.9%) had the lowest rate of antibiotic resistance. In addition, 67.9% (106/156) of UPEC isolates were ESBL producers. Most of UPEC isolates belonged to phylogenetic group B2 (37.1%). This study revealed that blaCTX-M and qnrS are widely distributed among UPEC isolates. The mean expression levels of fimA genes were significantly higher in non-biofilm producers than in biofilm producers (p < 0.01).

CONCLUSIONS

The high antibiotic resistance rates in this study highlight the significance of local resistance monitoring and investigating underlying mechanisms. Our findings indicate the dominance of phylogroup B2 and group D as the prevailing phylogenetic groups. Consequently, it is imperative to investigate the epidemiological aspects and characterize UPEC isolates across diverse regions and time frames.

Prevalence and drug resistance of Escherichia coli among patients with orthopaedic surgical site infections in China: A systematic review and meta-analysis

To summarize current prevalence and drug resistance rate of Escherichia coli (E. coli) among orthopaedic surgical site infections (SSIs) in China from English and Chinese language sources. Online databases were searched to collect related researches. A meta-analysis was performed to analyse prevalence and 95 % confidence interval (CI) of E. coli among patients with orthopedic surgical site infections. Meta-regression analysis was used to investigate the difference in the prevalence and antimicrobial resistance of E. coli among different subgroups. A total of 52 studies were enrolled into our meta-analysis, with a total of 31,285 strains isolated. The overall E. coli prevalence was 13.4 % (95 % CI 11.6-15.5). Study design (R2 = 8.98) and sample size (R2 = 10.95) might be potential sources of heterogeneity and there were no significant differences in risk of bias (R2 = 0.28), study time (R2 < 0.01), region (R2 = 2.46) and hospital level (R2 = 1.42). E. coli resistance were reported in 43 of the 52 papers. Antimicrobial resistance of E. coli to Ampicillin [87.9 % (95 % CI 83.7-91.1)] before 2015 was higher than that after 2015 [80.3 % (95 % CI 75.0-84.7)] (R2 = 30.93, P = 0.033). While, resistance rate to Cefepime and Amikacin was significantly higher before 2015 (R2 = 17.25 and 6.54, P = 0.043 and 0.048), i.e., 46.4 % (36.3-56.9), 19.9 % (13.8-27.7) and 29.1 % (19.4-41.2), 8.6 % (4.4-16.2) in 2015 and after. It is necessary to carry out long-term monitoring to understand the actual prevalence and antimicrobial resistance of E. coli to develop appropriate health care mechanisms.

Evaluating the Effects of Ertapenem and Meropenem on Tacrolimus

Purpose: Further elucidate the potential drug interaction between tacrolimus and carbapenems in order to appropriately maintain the balance between infection treatment and therapeutic immunosuppression. Methods: This study was a retrospective evaluation of solid organ transplant recipients on a stable dose of tacrolimus who received either ertapenem or meropenem. Patients were excluded if they had acute kidney injury, acute liver failure, concomitant initiation of medications that interact with tacrolimus, or were pregnant. The primary endpoint was the change in the median daily tacrolimus dose after meropenem or ertapenem administration. The secondary endpoint was the change in serum tacrolimus levels after meropenem or ertapenem administration. Results: A total of 28 patients on tacrolimus were included in the study, 12 received ertapenem and 16 received meropenem. The median daily tacrolimus dose was 4.5 mg [IQR 3.0 mg - 8.8 mg] prior to and 3.4 mg [IQR 2.3 mg - 8.8 mg] after ertapenem administration. The median daily tacrolimus dose was 3.0 mg [IQR 1.6 mg - 5.5 mg] before and 3.0 mg [IQR 1.6 mg - 5.5 mg] after meropenem administration. No statistically significant difference in regard to the change in the median daily tacrolimus dose after ertapenem (P =.173) or meropenem administration (P =.755) was observed. There was no statistically significant difference found after ertapenem (P =.583) or meropenem (P =.317) administration when comparing pre- and post-administration median serum tacrolimus levels. Conclusion: The administration of ertapenem or meropenem did not affect serum tacrolimus levels or daily tacrolimus dose suggesting against empiric dose adjustments with co-administration.

The Effectiveness of Cefazolin Prophylaxis on Infection after Transureteral Lithotripsy: A Randomized Clinical Trial

Background

Transureteral lithotripsy (TUL) is one of the most common surgeries in urology, and many TUL procedures have been performed with antibiotics prophylaxis. The present study investigates the effect of antibiotic prophylaxis on the rate of urinary infection after TUL.

Methods

This double-blind, randomized clinical trial was conducted on 158 patients with ureteral stones, with 79 in each group: the prophylaxis cefazolin group (Group A) and the placebo group (Group B). The patients were referred to Imam Hassan Hospital in Bojnurd, Iran. The standard technique of TUL operation was performed using a pneumatic lithoclast and a semirigid 9/8/Fr ureteroscope. The bacterial isolates were identified through growth on EMB agar and blood agar. Antimicrobial sensitivity testing (AST) was carried out by disc diffusion technique.

Results

According to our results, 157 patients were eligible for analysis; 79 patients in Group A and 78 patients in Group B. Flank pain and urinary complaints were the most common symptoms. Our findings indicate that cefazolin prophylaxis did not show any significant differences in preventing postoperative infection between the two groups. E. coli accounted for eight 10.1% (8/79) Group A and 9% (7/78) in Group B, respectively. The results of AST for the 15 E. coli strains revealed a high rate of antibiotic resistance against ampicillin (73.3%).

Conclusion

Our findings indicate that prophylactic antibiotic administration does not demonstrate effectiveness in reducing the infection rate following TUL surgery. Antibiotic prophylaxis is not recommended considering the potential adverse effects, cost implications, risk of antibiotic resistance, and lack of efficacy.

Aptitude of Uropathogenic Escherichia coli in Renal Transplant Recipients: A Comprehensive Review on Characteristic Features, and Production of Extended Spectrum β-Lactamase

Urinary tract infection is the most common infection in almost half of the renal transplant patients. The development of UTI in these patients may progress to bacteremia, acute T cell-mediated rejection, impaired allograft function, or allograft loss, along with the increased risk of hospitalization and death. Among various pathogens implicated, Uropathogenic E. coli (UPEC), especially sequence type 131 (ST131), is the most virulent and multidrug-resistant pathogen. High antimicrobial resistance to most β-lactam antibiotics, mediated by extended spectrum β-lactamases (ESBLs) produced by UPEC, is a challenge in the clinical management of UTIs in kidney transplant recipients. Indeed, multidrug resistance to β-lactam antibiotics is a direct consequence of ESBL production. Resistance to other antibiotics such as aminoglycosides, fluoroquinolones, and trimethoprim-sulphamethoxazole has also been reported in ESBLs-producing UPEC, which reduces the therapeutic options, rising healthcare-associated costs and subsequently leads to renal failure or even graft loss. In this review, we aimed to discuss the post-transplant risk factors of UTI, UPEC virulence factors (VF), and the related factors including quorum sensing, and stress resistance genes. Furthermore, we searched for the current treatment strategies and some of the alternate approaches proposed as therapeutic options that may affirm the treatment of ESBL-producing UPEC.

Uropathogenic Escherichia coli (UPEC)-Associated Urinary Tract Infections: The Molecular Basis for Challenges to Effective Treatment

Urinary tract infections (UTIs) are among the most common bacterial infections, especially among women and older adults, leading to a significant global healthcare cost burden. Uropathogenic Escherichia coli (UPEC) are the most common cause and accounts for the majority of community-acquired UTIs. Infection by UPEC can cause discomfort, polyuria, and fever. More serious clinical consequences can result in urosepsis, kidney damage, and death. UPEC is a highly adaptive pathogen which presents significant treatment challenges rooted in a complex interplay of molecular factors that allow UPEC to evade host defences, persist within the urinary tract, and resist antibiotic therapy. This review discusses these factors, which include the key genes responsible for adhesion, toxin production, and iron acquisition. Additionally, it addresses antibiotic resistance mechanisms, including chromosomal gene mutations, antibiotic deactivating enzymes, drug efflux, and the role of mobile genetic elements in their dissemination. Furthermore, we provide a forward-looking analysis of emerging alternative therapies, such as phage therapy, nano-formulations, and interventions based on nanomaterials, as well as vaccines and strategies for immunomodulation. This review underscores the continued need for research into the molecular basis of pathogenesis and antimicrobial resistance in the treatment of UPEC, as well as the need for clinically guided treatment of UTIs, particularly in light of the rapid spread of multidrug resistance.

The emergence of plasmid-encoded oxacillinase and carbapenemase among uropathogenic Escherichia coli (UPEC) isolated from hospitalized patients in the North of Iran

Carbapenemase enzyme production is responsible for resistance to carbapenem among Gram-negative bacteria. This study aimed to detect common carbapenemase and oxacilinase genes among uropathogenic E. coli (UPEC) isolated from hospitalized patients in Rasht, north of Iran. In the present study, from 2000 urine samples, 263 UPEC strains were isolated from inpatients with urinary tract infections (UTI) in 2020. The Kirby-Bauer disk diffusion susceptibility test was used to determine the sensitivity or resistance of isolates to antimicrobial compounds. The double-disk test confirmed extended-spectrum β lactamase (ESBL) production phenotypically, and the presence and distribution of genes encoding carbapenemase and oxacilinase were investigated using polymerase chain reaction (PCR). Based on the findings, 13/263 isolates (8 ESBL and five non-ESBL) showed a non-susceptible phenotype to at least one of the studied carbapenem group antibiotics, and 121 (46%) isolates were ESBL-producers. PCR for oxacilinase and carbapenemase genes was done on all 126 isolates, including ESBL-positive and carbapenem-resistant strains, in which 10 (7.9%) and 25 (19.8%) isolates harbored OXA-1 and IMP genes, respectively. Also, OXA-2, OXA-10, OXA-48, VIM, and NDM genes were not found in any studied isolates. IMP and OXA-1 genes among carbapenemase-producing isolates indicate the possible spread of antibiotic-resistant strains. Hence, identification and control of ESBL and carbapenemase-producing strains, although with almost low frequency due to plasmid genes encoding carbapenemase, is essential for infection control.

EVALUATION OF PHENOTYPIC AND MOLECULAR TECHNIQUE IN THE DETECTION OF EXTENDED SPECTRUM BETA-LACTAMASE (ESBL)-PRODUCING GRAM NEGATIVE BACILLI IN OGUN STATE, NIGERIA

Background

Molecular diagnosis though faster and more sensitive than phenotypic techniques, is more expensive. Resource limited settings are thus limited to using more of phenotypic rather than molecular methods in the routine detection of Extended Spectrum beta lactamases (ESBL).

Aim

This study aimed to evaluate the performance of double disc synergy test (DSST) and Epsilometer (E) test with Polymerase Chain Reaction (PCR) and to detect the risk factors associated with ESBL producing organisms among in-patients at Babcock University Teaching Hospital, Ilishan-Remo, Nigeria.

Methodology

Hospital-based cross-sectional study in which bacterial isolates of 165 in-patients were collected fromMarch 2018 to September 2019. The isolates were evaluated for ESBL production by the use of DDST, Etest and PCR. The performance evaluation was done. Questionnaire was used to assess the risk factors associated with ESBL, IBM SPSS Version 23 was used to analyze the data.

Results

The participants' isolates yielded 50/165 (30.3%) that were ESBL positive by DDST, 47/165 (28.9%) by E-test and 48/165(29.1%) by PCR. Sensitivity and specificity of DSST was 100% and 98.3% while that of E-test was 98% and 100% respectively. Age, antibiotics intake without prescription, being on ventilator, urethral catheterization and nasogastric tubes were all significantly associated with presence of ESBL (p value <0.05).

Conclusion

Phenotypic tests remain reliable for the routine detection of ESBL in the absence of molecular methods. Rational use of instrumentation and antibiotics is advocated based on the risk factors detected from this study.

Antibiotic Resistance of Uropathogenic <i>Escherichia coli</i> Isolated from Patients with Urinary Tract Infections at the Urological Inpatient Facility of the Saratov Clinical Hospital

The aim of the work was to study the profile of antibiotic resistance of uropathogenic Escherichia coli strains isolated from patients with urinary tract infections in the urological inpatient facility of the clinical hospital in the Saratov city, depending on appurtenance to phylogenetic groups and subgroups, as well as O-serogroups.

Materials and methods. We assessed sensitivity/resistance to 25 different antibacterial drugs in 102 strains of uropathogenic E. coli. The studies were carried out using the disk diffusion method. The production of extended spectrum beta-lactamases was evaluated by the double disk method. Carbapenemase output was determined using the CIM test. The PCR method was applied to determine appurtenance to phylogenetic groups and subgroups, O-serogroups, as well as the frequency of occurrence of the mcr‑1, mcr‑2, mcr‑3, mcr‑4, mcr‑5 genes encoding the proteins that mediate the development of resistance to colistin.

Results and discussion. It has been established that all strains of uropathogenic E. coli are more or less resistant to antibacterial drugs. All studied 102 strains showed resistance to 23 antibacterial drugs from 8 functional groups. The resistance of uropathogenic E. coli had certain differences depending on belonging to phylogenetic groups and subgroups, O-serogroups. Strains of uropathogenic E. coli with high resistance (up to 100 %) belonged to the B23 phylogenetic group, the main representatives of which are cultures of the most common O-25 serogroup. The production of extended-spectrum beta-lactamases has been phenotypically confirmed for 69 (67.6 %) strains. No carbapenemaseproducing cultures were found in the study. The mcr‑1 and mcr‑2 genes encoding resistance to colistin have been identified in 3 uropathogenic E. coli strains (2.9 %).

Molecular Factors and Mechanisms Driving Multidrug Resistance in Uropathogenic Escherichia coli-An Update

The rapid emergence of multidrug-resistant (MDR) bacteria indisputably constitutes a major global health problem. Pathogenic Escherichia coli are listed among the most critical group of bacteria that require fast development of new antibiotics and innovative treatment strategies. Among harmful extraintestinal Enterobacteriaceae strains, uropathogenic E. coli (UPEC) pose a significant health threat. UPEC are considered the major causative factor of urinary tract infection (UTI), the second-most commonly diagnosed infectious disease in humans worldwide. UTI treatment places a substantial financial burden on healthcare systems. Most importantly, the misuse of antibiotics during treatment has caused selection of strains with the ability to acquire MDR via miscellaneous mechanisms resulting in gaining resistance against many commonly prescribed antibiotics like ampicillin, gentamicin, cotrimoxazole and quinolones. Mobile genetic elements (MGEs) such as transposons, integrons and conjugative plasmids are the major drivers in spreading resistance genes in UPEC. The co-occurrence of various bacterial evasion strategies involving MGEs and the SOS stress response system requires further research and can potentially lead to the discovery of new, much-awaited therapeutic targets. Here, we analyzed and summarized recent discoveries regarding the role, mechanisms, and perspectives of MDR in the pathogenicity of UPEC.

Bacteriological Profile and Antimicrobial Susceptibility Patterns of Gram-Negative Bloodstream Infection and Risk Factors Associated with Mortality and Drug Resistance: A Retrospective Study from Shanxi, China

Objective

The aim of this study was to analyze the epidemiological of gram-negative bloodstream infection (GNBSI) and establish a risk prediction model for mortality and acquiring multidrug resistant (MDR), the extended spectrum beta-lactamases (ESBLs) producing and carbapenem-resistant (CR) GNBSI.

Methods

This retrospective study covered five years from January 2015 to December 2019. Data were obtained from Hospital Information System (HIS) and microbiology department records. The risk factors for mortality and acquiring MDR, ESBLs-producing and CR GNBSI were analyzed by univariable and multivariable analysis.

Results

A total of 1018 GNBSI cases were collected. A majority of GNBSI patients were in hematology ward (23.77%). There were 38.61% patients who were assigned in the 41–60 age group. Escherichia coli was the most common gram-negative organism (49.90%). Among isolates of GNBSI, 40.47% were found to be MDR strains, 34.09% were found to be ESBLs-producing strains and 7.06% were found to be CR strains. Escherichia coli was the most common MDR (71.36%) and ESBLs-producing strain (77.81%). Acinetobacter baumannii was the most common CR isolate (46.15%). Multivariate analysis indicated that diabetes mellitus, solid organ tumor, non-fermentative bacteria, MDR strain, central venous cannula, urinary catheter, therapy with carbapenems or tigecycline prior 30 days of infection were independent mortality risk factors for GNBSIs. Over all, therapy with tigecycline prior 30 days of infection was the mutual predictor for mortality of GNBSI, acquiring MDR, ESBLs-producing and CR GNBSI (OR, 8.221, OR, 3.963, OR, 3.588, OR, 9.222, respectively, all p < 0.001).

Conclusion

Collectively, our study implies that patients who were diagnosed as GNBSI had a younger age. Therapy with tigecycline was the mutual and paramount predictor for mortality of GNBSI, acquiring MDR, ESBLs-producing and CR GNBSI. Our investigation had provided a theoretical basis for the use of antibiotics and prevention and control of hospital infection in our region.

The Molecular Characterization and Risk Factors of ST131 and Non-ST131 Escherichia coli in Healthy Fecal Carriers in Tehran, Iran

Background: Commensal extended-spectrum β-lactamase (ESBL) producing Escherichia coli isolates in the gut can be the reservoir of virulence factors and resistance genes. Objectives: We investigated the molecular feature, risk factors, and quinolone/fluoroquinolone (Q/FQ) resistance in sequence type 131 (ST131) and non-ST131: ESBL-producing E. coli (EPE) isolates in healthy fecal carriers. Methods: A total of 540 fecal samples and its demographic data were collected from healthy adults in Tehran in 2018. ST131 isolates were identified by MLST analysis, and the characteristics of the virulence factor, phylogenic assay, and Q/FQ resistance genes in ST131 and non-ST131 were determined by polymerase chain reaction (PCR). Results: The EPE isolates mainly belonged to the commensal phylogenetic groups A (54.9%) and D (18.1%). The type 1 fimbriae (fimH; 89.6%) gene was the predominant virulence factor, and there was a significant correlation between ferric yersiniabactin uptake (fyuA; 52.9%), aerobactin receptor (iutA; 17.6%), and group II capsule synthesis (kpsMII; 35.3%) with ST131. In Q/FQ-resistant isolates, qnrS (19%) was the predominant gene, and mutations mostly occurred at codon S83 in GyrA The number of mutations in gyrA and parC genes was significantly higher in ST131 isolates than in non-ST131 isolates. There was a significant positive correlation between diabetes, male gender, and living in the south of the city with EPE carriage (P < 0.05). Conclusions: Accumulation of multiple virulence factors and high- level resistance to Q/FQ in some phylogroups (B2 and D), particularly ST131 isolates, require to be considered in detecting resistant isolates in healthy carriers. According to the risk factor for spreading of EPE isolates (diabetes, living in low-income parts of the city, and male gender), the necessary strategies are required to be developed to control the dissemination of antimicrobial-resistant isolates in the community.

Antibacterial, anti-biofilm, and anti-adhesive activities of melittin, a honeybee venom-derived peptide, against quinolone-resistant uropathogenic Escherichia coli (UPEC)

Here, we demonstrated the in vitro and in vivo antibacterial and anti-biofilm activities of melittin, a peptide derived from honeybee venom, against uropathogenic Escherichia coli (UPEC) resistant to quinolones. The minimum inhibitory concentration (MIC) of melittin varied from 0.5 to 8 μM. The bactericidal effect was considered rapid and potent (ranging from 3.0 to 6.0 h after incubation) against a quinolone-resistant and Extended Spectrum Beta-lactamase (ESBL)-producing UPEC strain. Prior exposure to melittin did not reduce the MIC of the quinolones tested, but it decreased the MIC of ceftizoxime by 8-fold due to its ability to form pores in the membrane. Furthermore, melittin disrupted mature biofilms (39.58% at 32 μM) and inhibited the adhesion of this uropathogen to the surfaces of urethral catheter. These results show that melittin is a promising molecule that can be incorporated into invasive urethral medical devices to prevent urinary infections caused by multidrug-resistant UPECs.

Distribution and Antibiotic Susceptibility Pattern of Multidrug-Resistant Bacteria and Risk Factors Among Kidney Transplantation Recipients with Infections Over 13 Years: A Retrospective Study

Background

Infection ranks as the most common complication after kidney transplantation (KT) and threatens outcomes of kidney transplantation recipients (KTR). This study aimed to investigate the microbiological profile of infection, assess bacterial resistance and identify risk factors for multidrug-resistant (MDR) bacterial infection among KTR.

Methods

During the study period, 866 recipients underwent kidney transplant surgery. We studied the distribution of pathogens, resistance rate of MDR bacteria and the risk factors of MDR bacterial infection.

Results

Totally, 214 species of pathogens (110 species were MDR bacteria) were isolated in 119 KTR. Escherichia coli (E. coli) was the most common bacteria of the infection. MDR extended spectrum β-lactamase (ESBL)-producing Enterobacteriaceae (ESBL-E) were most resistant to ampicillin, cefazolin, ciprofloxacin and complex sulfamethoxazole, while quite sensitive to imipenem, amikacin and piperacillin/tazobactam (PIT). All MDR gram-positive bacteria were quite sensitive to linezolid and vancomycin, except that MDR Staphylococcus was also susceptible to rifampicin. Female gender (OR = 3.497, 95% CI = 1.445–8.467, P = 0.006), pathogen types > 1 (OR = 3.832, 95% CI = 1.429–10.273, P = 0.008) and postoperative time < 3 months (OR = 0.331, 95% CI = 0.137–0.799, P = 0.014) were independent risk factors for MDR bacterial infection.

Conclusion

PIT and amikacin may be an alternative choice of ESBL-E infection. Rifampicin can also be prescribed for MDR Staphylococcus infection. MDR bacterial infection was associated with female gender, pathogen types more than 1 and 3 months postoperative period.

Prevalence of ESBL and AmpC genes in E. coli isolates from urinary tract infections in the north of Iran

Beta-lactam resistance in Gram-negative bacteria, especially Escherichia coli, is a main clinical problem. It is often caused by the production of β-lactamases, particularly extended-spectrum β-lactamases (ESBLs) or AmpC enzymes. This study was undertaken to characterize ESBL and AmpC producers among Escherichia coli isolates from urine samples. During six months, 263 E. coli isolates were detected by standard biochemical tests. The isolates were screened for ESBL production by the double-disk synergy test using Ceftazidime (30 μg) and Cefotaxime (30 μg) disks and confirmed by combined disk diffusion test using Clavulanic acid. AmpC production was confirmed by an AmpC disk test based on filter paper disks impregnated with EDTA. The presence of genes encoding TEM, SHV, CTX-M, CIT, FOX, MOX, ACC, and EBC were detected by PCR. 263 E. coli isolates were selected for the combined disk (Ceftazidime, Cefotaxime, and Clavulanic acid) assay in the disk agar diffusion test. In the combined disk assay, among 263 isolates, 121 (46%) isolates were detected as ESBLs, and none of the isolates were AmpC producers. PCR performed on all ESBL producers and blaSHV, blaTEM, and blaCTX-M were detected in 42 (34.7%), 44 (36.4%), and 47 (38.8%) cases, respectively. Also, from 48 Isolates with zone diameters of less than or equal to 18 mm to Cefoxitin, 7 (14.6%), 4 (8.3%), and 9 (18.8%) cases contained MOX, EBC, and CIT genes, respectively. DHA, FOX, and ACC genes were not detected in any sample. Since pathogens evolve in the hospital setting, updating local data, such as this research, offers scientific evidence to improve the outcome of nosocomial infections.

Genetic Diversity, Carbapenem Resistance Genes, and Biofilm Formation in UPEC Isolated from Patients with Catheter-Associated Urinary Tract Infection in North of Iran

BACKGROUND

Infections due to carbapenem-resistant Enterobacteriaceae (CRE) are associated in patients with urinary catheters alarming rate of emergency status. The aim of this study is to investigate the molecular causes of carbapenem resistance among UPEC as well as antimicrobial resistance trends. Additionally, the potential of isolates to produce biofilms, in addition to their clonal and genetic diversity, was investigated. Material and Methods. A cross-sectional study was accomplished on a collection of 76 non-duplicate UPEC isolates obtained from CAUTIs from May 2021 to September 2021. The modified carbapenem inactivation method (mCIM) and EDTA-modified carbapenem inactivation method (eCIM) test was performed for the detection of carbapenemase and metallo-beta-lactamase activity. Also, the presence of carbapenemase genes was determined using PCR assays. In 96-well microtiter plates, biofilm development was evaluated. ERIC-PCR was used to investigate the clonal and genetic variety of isolates.

RESULTS

A total of 76 confirmed UPEC isolates were obtained from patients mentioned to teaching hospitals in Babol, Iran. The results of antibiotic susceptibility testing revealed a high rate of antibiotic resistance against nalidixic acid (81.6%) and trimethoprim-sulfamethoxazole (80.3%). Among UPEC isolates, 63.2% and 13.2% of UPEC isolates were positive for MBL production. The frequencies of the studied genes are in order of bla _NDM (14.5%), bla _OXA-23 (2.6%), and bla _OXA-48 (2.6%). Forty-two isolates (55.3%) were positive for biofilm formation. ERIC-PCR revealed that UPEC isolates could be categorized into nine clusters A-I and five isolates were categorized as a singleton.

CONCLUSION

The high prevalence of MDR and carbapenemase-producing isolates among the UPEC strain in this investigation is concerning. Moreover, the bla _NDM was the most frequent cause of producing metallo-beta-lactamase and carbapenemase. Also, analysis revealed a partial genetic similarity among the studied isolates, indicating that the same UPEC clones may have spread to other hospital units.

Identification of metallo-β-lactamases and AmpC production among Escherichia coli strains isolated from hemodialysis patients with urinary tract infection

BACKGROUND

This study aimed to identify metallo-β-lactamases (MBLs) and AmpC β-lactamases-producing Escherichia coli isolates obtained from hemodialysis (HD) patients with urinary tract infections (UTI).

METHODS AND RESULTS

A total of 257 HD patients with UTI were included in this study, from which 47 E. coli isolates were collected. Antibiotic susceptibility was tested by disc diffusion method. MBLs and AmpC production were phenotypically detected by imipenem-ethylenediaminetetracetate and cefoxitin/boronic acid assays, respectively. The presence of MBLs and AmpC genes was examined by polymerase chain reaction (PCR). Fosfomycin and ampicillin were the most and the least effective antibiotics against E. coli isolates, respectively. Moreover, 61.7% (29/47) of E. coli isolates were multidrug-resistant with seven different antibiotypes. Antibiotype V (AMP-CIP-IMP-MEM-CPD-CRO-CTX-GEN-LEV-SXT-TOB) was the most prevalent profile. Besides, 24 (51.1%) isolates were simultaneously resistant to imipenem and meropenem. Phenotypic assay showed MBL production in 16 (66.7%) of the 24 carbapenem-resistant E. coli isolates. The distribution of MBL genes in carbapenem-resistant E. coli was as follows: blaIMP 18 (72%), blaVIM 7 (28%), and blaNDM 1 (4%). AmpC was detected in 61.7% (29/47) of the isolates using the phenotypic method. The presence of AmpC genes was confirmed by PCR in only 26 of 29 (86.7%) AmpC producers. The frequencies of blaDHA-1, blaACC, and blaCMY-2 were 6 (20.7%), 11 (37.9%), and 21 (72.4%), respectively.

CONCLUSIONS

The emergence of MBL and AmpC coproducing E. coli isolates calls for an urgent surveillance program for timely diagnosis and screening of these genes in our healthcare systems.

Antibiotic Resistance and Virulence Genes of Escherichia coli Isolated from Patients with Urinary Tract Infections After Kidney Transplantation from Deceased Donors

Objective

This study aimed to determine the prevalence of antibiotic resistance and virulence genes of Escherichia coli strains among patients with urinary tract infections (UTIs) after kidney transplantation from deceased donors.

Methods

Between January 2014 and June 2018, 64 patients who received kidney transplants from deceased donors at our institution developed a UTI due to E. coli. Polymerase chain reaction was used to detect virulence genes in E. coli strains. The Kirby–Bauer method was used to evaluate the antibiotic susceptibility pattern of the isolates.

Results

Among the study cohort, 46 (71.9%) UTIs were community-acquired (CA), and 18 (28.1%) were hospital-acquired (HA). The percentages of isolated E. coli strains that showed antibiotic resistance were as follows: 92.2% to ampicillin, 76.6% to cefalotin, 81.3% to carbenicillin, 29.7% to ciprofloxacin, 62.5% to cotrimoxazole, 35.9% to gentamicin, 34.4% to levofloxacin, 28.1% to norfloxacin, 68.8% to pefloxacin, 57.8% to trimethoprim/sulfamethoxazole, and 20.3% to amikacin. HA E. coli showed higher resistance to ciprofloxacin, cotrimoxazole, trimethoprim/sulfamethoxazole and amikacin, compared with CA E. coli (P<0.05). The most prevalent virulence genes among the E. coli strains were fim (64.1%), followed by irp2 (56.3%), iroN (46.9%), pap GII (45.3%), sfa (31.3%), pap (25%), iuc (23.4%), pap GI (15.6%), pap GIII (14.1%), hly (9.4%), and cnf (4.7%). The irp2 and iroN genes were found more frequently in the HA E. coli than in the CA E. coli (P<0.05).

Conclusion

The E. coli strains, especially HA E. coli, isolated from UTI patients after kidney transplantation from deceased donors showed resistance to multiple antibiotics and harbored numerous virulence genes. These findings provide insight for genetic characterizations and epidemiological studies of E. coli strains causing UTIs in patients after kidney transplantation from deceased donors.

Infectious events in kidney transplant recipients from deceased expanded criteria donors: a prospective cohort

OBJECTIVE

Analyze risk factors for infection in kidney transplant recipients from deceased expanded criteria donors (DECD) in the first two years of follow-up.

METHOD

This is a prospective cohort study with 466 patients from DECD who underwent kidney transplantation in 2015 and 2016 in Brazil. A total of 551 events were recorded. The largest incidence of infectious events occurred in the first month after kidney transplantation. Cytomegalovirus infection was the most common infectious episode.

RESULTS

The incidence rate of infections was 57.1%. Among bacterial infections, only 4% were due to multidrug-resistant microorganisms. The death rate was 3.3% (15) patients. The main cause of death was infectious (73.3%). Hospitalization until the first infection (aOR:1.61), Number of infections in 1 year (aOR:40.16), and Cytomegalovirus infection (aOR:13.84) was risk factors for infection by multidrug resistant microorganisms (MDR).

CONCLUSION

Infection incidence with MDR bacteria was high among kidney transplant recipients from DECD, and the main cause of death was infection. Survival was high among patients with infection.

Molecular epidemiology of blaCTX-M gene-producing uropathogenic Escherichia coli among Iranian kidney transplant patients: clonal dissemination of CC131 and CC10

Background

This study aimed to investigate the phylogenetic characterization and virulence traits of uropathogenic Escherichia coli (UPEC) isolated from kidney transplant patients (KTPs) as well as non-KTPs and analyze the clonal distribution of Extended spectrum β-lactamases (ESBLs)-producing UPEC containing bla_CTX-M gene.

Methods

To this end, we determined virulence marker and the phylogenetic characterization of UPEC in non-KTPs (n = 65) and KTPs (n = 46). The non-KTPs were considered the control group of the study. Also, according to the Achtman scheme, we performed multilocus sequence typing to assess the relationship between twenty-nine of ESBL-producing isolates containing bla_CTX-M gene.

Results

According to the results of PCR assay, the prevalence of virulence factor genes ranged from 0% (cnf and papG III) to 93.7% (fimH). Also, KTP isolates significantly differed from non-KTP isolates only in terms of the prevalence of pap GI elements. Moreover, the most frequent UPEC isolates were in phylogenetic group B₂, followed by group D (18.9%), and group A (13.5%). Furthermore, except for phylogenetic group C, there was no significant correlation between phylogenetic distribution in KTPs and non-KTPs. Additionally, MLST analysis of bla_CTX-M carrying isolates identified 18 unique sequence types (ST) the most common of which was ST131 (24.1%), followed by ST1193 (10.3%), while fourteen STs were detected only once.

Conclusions

The results further revealed significant differences between the UPEC isolates from KTPs and non-KTPs regarding the phylogroups C and PAI gene. Based on MLST analysis, we also observed a relatively high diversity in UPEC isolates obtained from KTPs and non-KTPs. Moreover, clonal complex (CC) 131 and ST131 were found to be the most prevalent clones and ST types, respectively. Besides, for the first time, ST8503 were reported in KTPs. These results suggested regular studies on characterization of UPEC isolates among KTPs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12941-021-00470-7.

Antimicrobial resistance patterns of bacterial pathogens their distribution in university teaching hospitals in Zambia

Aim: To determine the antimicrobial resistance patterns of bacterial pathogens from urine, blood and wound infections and their distribution by age, sex and location. Materials & methods: A total of 49,168 samples were collected, processed and analyzed. Results: Multidrug resistance was observed in almost all bacterial pathogens in blood urine and wound swabs. In urine and females odds ratio (OR) = 0.864, p = 0.023, OR = 0.909, p = 0.013 urine and neonates were susceptible to antibiotics OR = 0.859, p = 0.003, OR = 0.741, p < 0.001. Ampicillin resistance was above 90% against Escherichia coli in blood, urine and wound swabs. Conclusion: There was a spike in resistance to imipenem, ciprofloxacin and ampicillin against E. coli, Klebsiella pneumoniae, Proteus mirabilis and Proteus species from all three specimen sources.

From the Urinary Catheter to the Prevalence of Three Classes of Integrons, β-Lactamase Genes, and Differences in Antimicrobial Susceptibility of Proteus mirabilis and Clonal Relatedness with Rep-PCR

Introduction

Proteus mirabilis is a biofilm-forming agent that quickly settles on the urinary catheters and causing catheter-associated urinary tract infections. Thus, the spread of multidrug-resistant P. mirabilis isolates, with the ability to form a biofilm that carries integron, extended-spectrum β-lactamases (ESBLs), and plasmid-mediated colistin resistance genes (mcr), represents a severe threat to managing nosocomial infectious diseases. This study is aimed at surveying the prevalence of ESBL, integrase, and mcr genes of P. mirabilis, isolated from the catheter, to assess the differences in their antimicrobial susceptibility and clonal dissemination.

Method

Microtiter plate assay was adopted to measure biofilm formation. The antimicrobial susceptibility was assessed by the disk diffusion method. Antimicrobial resistance genes (intI1, intI2, intI3, bla_TEM, bla_CTX-M, bla_SHV, mcr1, and mcr2) were detected by PCR. All of the isolates were characterized by repetitive sequence-based PCR.

Result

From 385 collected catheters in patients admitted to the intensive care unit (ICU), 40 P. mirabilis were isolated. All of the isolates could form a biofilm. Proteus spp. had intrinsic resistance to tetracycline (95%) and nitrofurantoin (92.5%), which explains the high resistance prevalence. The most widely resistant antibiotic was trimethoprim-sulfamethoxazole (75%). Thirty-three (82.5%) isolates were classified as multidrug resistance (MDR). The prevalence of intI1 and intI2 genes was 60% and 25%, respectively. In 6 (15%) isolates, both genes were detected. The most frequent ESBL gene detected in all of the isolates was bla_TEM. Also, no detection for mcr1 and mcr2 antibiotic resistance genes was reported. Rep-PCR identified 39(GTG)5 types (G1–G39) of 40 isolates that 38 isolates had unique patterns.

Conclusion

In this study, 82.5% of isolates were MDR with high antibiotic resistance to trimethoprim-sulfamethoxazole. The intI1 and bla_TEM were the most prevalent genes in the integrase and ESBL gene family. High diversity was seen in the isolates with Rep-PCR. The increasing rate of MDR isolates with a high prevalence of resistance genes could be alarming and demonstrate the need for hygienic procedures to prevent the increased antibiotic resistance rate in the future.

Molecular characterization of ESBL- producing uropathogenic Escherichia coli recovered from urine samples of patients attending a University Teaching hospital in Nigeria

Infection of the urinary tract ranks as one of the most common infections affecting people worldwide and its treatment is made complicated by the rising incidence of antibiotic resistance. This study aimed to detect extended spectrum beta-lactamase (ESBL) genes and antibiotic resistance profile of uropathogenic Escherichia coli (E. coli) recovered from patients attending a University Teaching hospital in Nigeria. Uropathogenic E. coli isolates were obtained from the culture collection of Department of Microbiology and Parasitology of the University Teaching hospital for a period of four months (October 2019-January, 2020). Antibiotic susceptibility testing was done using the disc diffusion method while phenotypic ESBL production was detected using double disc synergy test (DDST). Detection of β-lactamase genes was done using Real-Time PCR. Forty-nine E. coli isolates were recovered from 120 urine samples, with 24 (49%) being ESBL positive. The resistance to antibiotics in the ESBL producers was: ciprofloxacin (100%), cefotaxime (100%), cefpodoxime (100%), tetracycline (95.7%), ceftazidime (56.7%), amoxicillin-clavulanate (50%), gentamicin (33.3%), and imipenem (0%). All the ESBL producers carried blaTEM, blaCTX-M-1 and blaCTX-M-9, 75% (18/24) carried blaSHV, while blaCTX-M-2, blaCTX-M-8 and blaCTX-M-25 groups were detected in 20.8% (5/24) of the isolates. There was co-occurrence of CTX-M, SHV and TEM β-lactamases in 79.2% (19/24) isolates, while five isolates (20.8%) co-harbored blaCTX-M and blaTEM. This study showed a high level of multidrug resistance and ESBL gene carriage in uropathogenic E. coli obtained in this study, suggesting a likely review of therapeutic options in the treatment of UTI to clamp down on the rising cases of antibiotic resistance.

A retrospective cross-sectional survey on nosocomial bacterial infections and their antimicrobial susceptibility patterns in hospitalized patients in northwest of Iran

Objective

Nosocomial infections (NIs) are known as one of the remarkable problems in all countries. This study is aimed to estimate the prevalence rate of nosocomial bacterial agents with antimicrobial susceptibility pattern in hospitalized patients. This study was conducted from April 2017 to September 2018, on 4029 hospitalized patients. We set out to recognize the commonest bacterial infections and antimicrobial susceptibility patterns of nosocomial infection.

Results

Of the 4029 patients, 509 (12.6%) of them were culture positive. Of these Escherichia coli (E. coli) (98.3%) and Staphylococcus epidermidis (S. epidermidis) (37.5%) were the most abundant bacterial identified in the urinary tract and bloodstream cultures respectively, Moreover, Acinetobacter spp. (100%) and Pseudomonas aeruginosa (22.2%) were the most abundant organisms detected in the respiratory system. According to susceptibility testing results, 370 (80.5%) and 264 (57.3%) in Gram-negatives and 44 (91.7%) and 35 (72.9%) in gram positives isolated strains were classified as multidrug-resistant (MDR) and extensive drug-resistant (XDR) strain respectively. On account of the high prevalence of MDR and XDR bacterial species, there is a pressing need for the expansion of new strategies on antibiotic supervision and infection control to introduce new guideline on empirical antibiotic therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-021-05503-0.

Nitrofurantoin Combined With Amikacin: A Promising Alternative Strategy for Combating MDR Uropathogenic Escherichia coli

Urinary tract infections (UTI) are common infections that can be mild to life threatening. However, increased bacterial resistance and poor patient compliance rates have limited the effectiveness of conventional antibiotic therapies. Here, we investigated the relationship between nitrofurantoin and amikacin against 12 clinical MDR uropathogenic Escherichia coli (UPEC) strains both in vitro and in an experimental Galleria mellonella model. In vitro synergistic effects were observed in all 12 test strains by standard checkerboard and time-kill assays. Importantly, amikacin or nitrofurantoin at half of the clinical doses were not effective in the treatment of UPEC infections in the G. mellonella model but the combination therapy significantly increased G. mellonella survival from infections caused by all 12 study UPEC strains. Taken together, these results demonstrated synergy effects between nitrofurantoin and amikacin against MDR UPEC.

Prevalence, serotyping and drug susceptibility patterns of Escherichia coli isolates from kidney transplanted patients with urinary tract infections

BACKGROUND

Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (E. coli) are among the main pathogens in urinary tract infections (UTIs) among kidney transplant patients (KTPs).

AIM

To estimate the prevalence of ESBL-producing E. coli in KTPs and to evaluate the most prevalent serotypes and antibacterial susceptibility patterns of isolated bacteria in Tehran, Iran.

METHODS

A total of 60 clinical isolates of uropathogenic E. coli were collected from 3 kidney transplant centers from April to May 2019. Antimicrobial susceptibility testing was performed by the disk diffusion method as recommended by the Clinical Laboratory and Standards Institute. The serotyping of E. coli isolates was performed by the slide agglutination method. The presence of bla_TEM, bla_SHV, and bla_CTX-M genes was evaluated by polymerase chain reaction.

RESULTS

The frequency of ESBL-producing E. coli in KTPs was found to be 33.4%. All of the 60 E. coli isolates were found to be susceptible to doripenem (100%) and ertapenem (100%). High resistance rates to ampicillin (86%), cefotaxime (80%), and cefazolin (77%) were also documented. The most frequent serotypes were serotype I (50%), serotype II (15%), serotype III (25%), and serotype VI (10%). The gene most frequently found was bla_TEM (55%), followed by bla_CTX-M (51%) and bla_SHV (41%).

CONCLUSION

Molecular analysis showed that bla_TEM was the most common ESBL-encoding gene. The high resistance to β-lactams antibiotics (i.e., ampicillin, cefotaxime, and cefazolin) found in E. coli from KTPs with UTIs remains a serious clinical challenge. Further efforts to control ESBL-producing E. coli should include the careful use of all antibiotics as well as barrier precautions to reduce spread.

Characterization of Plasmid-Mediated Quinolone Resistance and Serogroup Distributions of Uropathogenic Escherichia coli among Iranian Kidney Transplant Patients

Introduction

Urinary tract infection (UTI) is one of the most frequent infections in kidney transplant patients (KTPs). This infection is mainly caused by uropathogenic Escherichia coli (UPEC). Plasmid-mediated quinolone resistance (PMQR) was also increasingly identified in UPEC. This study proposed to investigate the frequency of quinolone-resistance plasmid genes and the O-antigen serogroup among UPEC isolated from KTPs and non-KTP with UTI.

Methods

Totally, 114 UPEC isolates from 49 KTPs and 65 non-KTPs patients diagnosed with an UPEC-associated UTI were obtained from June 2019 to December 2019 at three laboratory centers in Isfahan, Iran. The isolates were confirmed through phenotypic and genotypic methods. Moreover, the antimicrobial susceptibility test to nalidixic acid, ciprofloxacin, norfloxacin, and ofloxacin was performed using a disk diffusion method. The presence of the qnr gene as well as the serogroup distribution was identified using the PCR method.

Result

According to data, the distribution of O1, O2, O4, O16, and O25 serogroups were 3.5%, 2.6, 3.5, 3.5, and 20.2%, respectively. Antibiotic susceptibility pattern revealed that the highest and lowest resistance rates were to nalidixic acid (69.3%) and norfloxacin (43.9%), respectively. Also, the frequency of qnrS and qnrB genes were 33.3% and 15.8%, respectively, while none of the isolates was found to be positive for the qnrA gene. There was no significant association between the presence of qnr genes and higher antibiotic resistance.

Conclusion

This study recognized that the qnrS gene, O25 serotype, and resistance to nalidixic acid had the highest frequencies in UPEC strains isolated from UTI patients.

Characterization of Hypervirulent Extended-Spectrum β-Lactamase-Producing Klebsiella pneumoniae Among Urinary Tract Infections: The First Report from Iran

Introduction

This study was conducted to identify the hypermucoviscosity, iron acquisition, and capsule serotypes of K. pneumoniae strains isolated from urinary tract infections among community-acquired patients (CA) and assess the frequency of plasmid-mediated quinolone resistance (PMQR) and extended-spectrum beta-lactamases (ESBL) genes between classic and hypervirulent strains.

Materials and Methods

A total of 105 K. pneumoniae were isolated from CA-UTI. Demographic data related to the underlying diseases and clinical manifestations were further collected. Antibiotic resistance pattern and molecular characterization were compared among ESBL-positive, ESBL-negative, hypervirulent, and classic isolates.

Results

The results revealed that 52.4% of the isolates were confirmed as ESBL producers and 11 (10.5%) were considered as hypervirulent K. pneumoniae (hvKp). Ciprofloxacin and nalidixic acid were the most inactive antibiotics with resistance rates of 68.6% and 64.8%, respectively. Molecular characterization revealed that 7.6% of all the isolates carried k1 and 66.6% carried K2 genes. The most frequent ESBL gene was bla_SHV 63.8%, followed by bla_TEM 59.0%, and bla_CTX-M 58.1%. ESBL genes were significantly more in hvKp than in cKp. Moreover, 61 (84.7%), 47 (65.2%), and 16 (22.2%) of isolates harbored qnrB, qnrS, and qnrA. ESBL genes were detected in all hvKps, and bla_SHV was observed in 90.9% of hvKp (P value= 0.048, 95%).

Discussion

This study reported the high frequency of antimicrobial and multidrug resistance among hvKp isolates. Coexistence of PMQR and ESBL genes in hvkp indicates the necessity to enhance the clinical knowledge and management of hvKp infections.