Urinary tract infections among kidney transplant patients due to extended-spectrum beta-lactamase-producing bacteria

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.

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

Introduction

The aim of this study was to investigate the antimicrobial susceptibility pattern and the presence of ESBLs among the uropathogenic Escherichia coli (UPEC) isolated from kidney transplant patients (KTP) and community-acquired urinary tract infections (UTIs) using phenotypic and molecular methods.

Materials and Methods

A total of 111 pure cultures of UPEC isolates were collected from 65 and 46 of non-KTP and KTPs with UTIs. The pattern and ESBL production of the strains were evaluated. PCR reaction to detect the presence of bla _SHV, bla _TEM, and bla _CTX-M genes was performed.

Results

The results revealed that most of UPEC isolates obtained from KTPs and control group were resistant to trimethoprim/sulfamethoxazole (84.8% vs 46.2%), while carbapenems (100% sensitivity) were the most effective against UPEC isolates. ESBL-producing strains were significantly more frequent in KTPs compared with control group (43.5% vs 23.1%, P = 0.021). The molecular results revealed that 53.2% (59/111), 45% (50/111), and 5.4% (6/111) of isolates harbored bla _CTX-M, bla _TEM, and bla _SHV genes, respectively. Of the genes investigated, bla _CTX-M and bla _TEM genes were significantly higher among KTP than the control group.

Conclusion

Our results showed a high proportion of multidrug-resistant and ESBL-producing isolates, which most of them harbor blaCTX-M. A significant high co-resistance to different classes of antibiotics was reported from ESBL-producing UPEC from KTPs, which remains a serious clinical challenge.

Emergence of vancomycin-intermediate and -resistant Staphylococcus aureus among methicillin-resistant S. aureus isolated from clinical specimens in the northwest of Iran

OBJECTIVES

The aim of this study was to evaluate the frequency as well as the phenotypic and molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant S. aureus (VRSA) isolates from clinical specimens at three university teaching hospitals in Urmia, Northwest Iran, from 2012-2015.

METHODS

Following identification of the isolates, antibiotic susceptibility testing was performed. The presence of the mecA, vanA and pvl genes was evaluated, and staphylococcal cassette chromosome mec (SCCmec) typing was performed.

RESULTS

A total of 177 S. aureus isolates were collected from various clinical specimens. Antibiotic susceptibility testing revealed high resistance rates to penicillin (98.9%), followed by erythromycin (61.6%). A total of 95 isolates (53.7%) were confirmed as MRSA. Among the initially screened vancomycin-intermediate S. aureus (VISA) isolates, one isolate with a minimum inhibitory concentration (MIC) of 6μg/mL harboured the vanA gene. Eleven MRSA isolates (11.6%) were also VRSA. A majority (23/95; 24.2%) of MRSA were classified as SCCmec type III. Only 6 MRSA isolates (6.3%) harboured the pvl gene.

CONCLUSIONS

This study highlights the presence of MRSA along with VISA and VRSA in our setting. To our knowledge, this is the first report showing that a strain can be defined as VISA phenotypically and as VRSA by molecular analysis. Such a finding raises major concerns with regard to control measures and reliable laboratory tests for screening of resistant strains.