Virulence Gene Profile and Multilocus Variable-Number Tandem-Repeat Analysis (MLVA) of Enteroinvasive Escherichia coli (EIEC) Isolates From Patients With Diarrhea in Kerman, Iran

Background: Enteroinvasive Escherichia coli (EIEC) isolates cause dysentery in humans. Several virulence factors associated with EIEC pathogenesis have been characterized. Multilocus variable-number tandem-repeat analysis (MLVA) is a PCR-based method that has been used for genotyping bacterial pathogens. Objectives: The aim of this study was to investigate the distribution of virulence factor genes in EIEC isolates from patients with diarrhea in Kerman, Iran, as well as the genetic relationships between these isolates. Patients and Methods: A total of 620 diarrheic stool samples were collected from patients attending two hospitals in Kerman from June 2013 to August 2014. All isolates were confirmed as EIEC by PCR for the ipaH gene. The EIEC isolates were evaluated by PCR for the presence of nine virulence genes (ial, set1A, sen, virF, invE, sat, sigA, pic, and sepA). MLVA was performed for all EIEC isolates. Results: A total of 11 EIEC isolates were identified, and all were positive for the ial gene. The invE and virF genes were observed in 81.8% of the isolates, while sen, sigA, and pic were detected in 72.7%, 63.6%, and 27.3% of the isolates, respectively. None of the isolates were positive for the sat, set, and sepA genes. Using MLVA, the 11 total isolates were divided into five types. Conclusions: By studying the profiles of virulence genes and MLVA, it can be concluded that EIEC isolates do not have high heterogeneity and are derived from a limited number of clones. Keywords: EIEC, MLVA, Virulence Factors, Diarrhe

Prevalence of qnr, intI, and intII genes in extendedspectrum beta-lactamase (ESBL)-producing Escherichia coli isolated from clinical samples in Iran

Purpose: To investigate the prevalence of qnr, intI, and intII genes in extended spectrum betalactamase (ESBL)-producing Escherichia coli isolated from clinical samples in Kerman, Iran.Methods: A total of 127 E. coli were collected from clinical samples in Kerman hospitals. The antibiotic susceptibility test was performed using disc diffusion method, while the presence of ESBL-producing E. coli was determined by phenotypic confirmatory test. Furthermore, the presence of qnrA, qnrB, qnrS, intI, intII, and β-lactamase-encoding genes was detected by polymerase chain reaction (PCR). Finally, the data were analyzed and associations between different genes and antibiotic resistance were evaluated.Results: The highest and lowest rates of resistance were observed against ampicillin (72.4 %) and imipenem (2.3 %), respectively. Also, 41.7 % of the isolates produced ESBL-enzymes. The qnrS and genes were detected in 6.3 and 0.78 %, respectively, of the isolates, while qnrA gene was not detected in the current study. The results revealed that 64.5 and 10.2 % of isolates carried intI and intII genes, respectively. Data analysis showed a significant association between ESBL production and class I integrin gene in E. coli isolates.Conclusions: Due to the variation in the resistance patterns of E. coli against antibiotics in different geographical regions, antimicrobial treatments should be based on local experience. Also, the coexistence of ESBL and intI gene in the majority of E. coli isolates suggests that care should be taken in choosing antibiotic therapy.Keywords: Extended-spectrum β-lactamase, E. coli, Integrin, Imipenem, Bacterial genes, Antibiotic resistanc

Prevalence of bla-CTX-M, bla-SHV, and bla-TEM Genes and Comparison of Antibiotic Resistance Pattern in Extended-spectrum β-lactamase producing and non-producing groups of Klebsiella pneumoniae Isolated from Clinical Samples in Kerman Hospitals

Background & Objectives: Antibiotic resistance among pathogens bacteria are an important problem noted worldwide. Beta-lactamases that are produced by Enterobacteriaceae have been located mainly on plasmid. Treatment of these bacterial infections which produced β-lactamase are a major problem. Materials & Methods: 111 Klebsiella pneumoniae isolates were collected from hospitals in Kerman; therefore, antibiotic susceptibility test was performed by disk diffusion method. At first, detection of ESBLs were performed by phenotypic confirmatory test, and presence of bla-SHV, bla-TEM, and bla-CTX-M were detected by PCR. Results: Resistant to ampicillin (92.5%) was more than others antibiotics, and the imipenem (89%) was the most effective antibiotic against Klebsiella pneumoniae isolates. Additionally, the resistance to all antibiotics in ESBLs-producing Klebsiella pneumoniae was more than that of Non-ESBL Klebsiella pneumoniae. After the detection of bla-SHV, bla-TEM, and bla-CTX-M genes in Klebsiella pneumoniae by PCR, 56 (50.4%) isolates presented these genes. Conclusion: With regard to high prevalence of ESBLs genes and high level of antibiotic resistance in bacteria, detecting these genes can prevent the extension of antibiotic resistance through these bacteria

Upregulation of pmrA, pmrB, pmrC, phoQ, phoP, and arnT genes contributing to resistance to colistin in superbug Klebsiella pneumoniae isolates from human clinical samples in Tehran, Iran

Background: Antibiotic resistance in Klebsiella pneumoniae isolates, particularly resistance to colistin, has become a growing concern. This study seeks to investigate the upregulation of specific genes (pmrA, pmrB, pmrC, phoQ, phoP, and arnT) that contribute to colistin resistance in K. pneumoniae isolates collected from human clinical samples in Tehran, Iran. Methods: Thirty eight K. pneumoniae isolates were obtained and subjected to antibiotic susceptibility testing, as well as evaluation for phenotypic AmpC and ESBL production according to CLSI guidelines. The investigation of antibiotic resistance genes was conducted using polymerase chain reaction (PCR), whereas the quantification of colistin resistance related genes expressions was performed via Real-Time PCR. Results: The highest and lowest antibiotics resistance were observed for cefotaxime 33 (86.8%) and minocycline 8 (21.1%), respectively. Twenty-four (63.2%) and 31 (81.6%) isolates carried AmpC and ESBLs, respectively. Also, antibiotic resistance genes containing blaNDM, blaIMP, blaVIM, blaSHV, blaTEM, blaCTXM, qnrA, qnrB, qnrS, and aac(6')-Ib were detected in K. pneumoniae isolates. Only 5 (13.1%) isolates were resistant to colistin and the MIC range of these isolates was between 4 and 64 μg ml−1. Upregulation of the pmrA, pmrB, pmrC, phoQ, phoP, and arnT genes was observed in colistin-resistant isolates. The colistin-resistant isolates were found to possess a simultaneous presence of ESBLs, AmpC, fluoroquinolone, aminoglycoside, and carbapenem resistant genes. Conclusions: This study reveals escalating antibiotic resistance in K. pneumoniae, with notable coexistence of various resistance traits, emphasizing the need for vigilant surveillance and innovative interventions