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Papers by masih FAtemi

Introduction: Carbapenem-resistant Enterobacteriaceae (CRE) bacteria are difficult to treat becau... more Introduction: Carbapenem-resistant Enterobacteriaceae (CRE) bacteria are difficult to treat because of their high antibiotic resistance levels that can be mediated by carbapenemase enzymes such as Klebsiella Pneumoniae Carbapenemase (KPC). The purposes of this study were to determine the genetic and resistance patterns and to detect of KPC enzyme in carbapenem-resistant strains of Enterobacteriaceae isolates. Materials and methods: In this study, antibiotic resistant pattern and genotyping of carbapenem-resistant Enterobacteriaceae isolates and frequency of KPC enzyme were investigated. During 16 months of conducting the study (December 2016 until April 2018), strains of Escherichia coli, Enterobacter spp. and Citrobacter spp. were isolated and identified from different clinical specimens and antibiotic susceptibility test was determined. In addition, the prevalence of the KPC enzyme was determined by PCR and two phenotypic methods including Modified Hodge Test (MHT) and the combina...

Probiotics and Antimicrobial Proteins, 2017

The emergence of antibiotic-resistant and food-spoilage microorganisms has renewed efforts to ide... more The emergence of antibiotic-resistant and food-spoilage microorganisms has renewed efforts to identify safe and natural alternative agents of antibiotics such as probiotics. The aim of this study was the isolation of lactobacilli as potential probiotics from local dairy products with broad antibacterial and anti-biofilm activities against antibiotic-resistant strains of Pseudomonas aeruginosa and determination of their inhibition mechanism. Antibiotic susceptibility and classification of acquired resistance profiles of 80 P. aeruginosa strains were determined based on Centers for Disease Control and Prevention (CDC) new definition as multidrug-resistant (MDR), extensively drug-resistant (XDR), and pan-drug-resistant (PDR) followed by antibacterial assessment of lactobacilli against them by different methods. Among the 80 P. aeruginosa strains, 1 (1.3%), 50 (62.5%), and 78 (97.5%) were PDR, XDR, and MDR, respectively, and effective antibiotics against them were fosfomycin and polymyx...

Middle East Journal of Digestive Diseases, 2018

BACKGROUND Cholecystitis is a common surgical condition. Recently, several authors have reported ... more BACKGROUND Cholecystitis is a common surgical condition. Recently, several authors have reported that DNA of bile tolerant Helicobacter spp. has been found in the human bile colonizing the biliary tract. The aim of this study was to evaluate the association between the presence of Helicobacter spp. and gallstone cholecystitis. METHODS In this case-control study, gallstones, bile, and gallbladder mucosa were collected from 25 patients without gallstone disease, 24 with acute cholecystitis, and 28 with chronic cholecystitis. The presence of Helicobacter pylori (H. pylori), Helicobacter bilis (H. bilis), Helicobacter hepaticus (H. hepaticus) , and Helicobacter pullorum (H. pullorum) were investigated by polymerase chain reaction (PCR) using species-specific primers. RESULTS In this study, 77 subjects with acute and chronic cholecystitis and control groups with a mean age of 46.85 ± 14.53 years, including 58 (67.25%) women and 19 (32.75%) men were included. DNA of 10 Helicobacter spp. w...

Comparative Clinical Pathology, 2018

New Delhi metallo-beta-lactamase (NDM) and CMY-2-AmpC β-lactamase are among the most important re... more New Delhi metallo-beta-lactamase (NDM) and CMY-2-AmpC β-lactamase are among the most important resistance factors against carbapenem and beta-lactam antibiotics. Considering the few studies in Iran, here NDM and CMY-2 production in Escherichia coli (E.coli) and Enterobacter isolates were evaluated. Acquired resistance profiles of isolates were determined based on the new definitions as multi-drug resistant (MDR), extensively drug-resistant (XDR) and pan-drug resistant (PDR). In carbapenem-resistant strains, minimum inhibitory concentration (MIC) of different antibiotics by Etest method and the clonal relationship using enterobacterial repetitive intergenic consensus (ERIC)-PCR were determined. The frequency of blaNDM and blaCMY-2 was examined using phenotypic methods and PCR. Among 466 E.coli and 135 Enterobacter isolates, 42 and 28 different resistotypes were observed, respectively. In E.coli strains, 88 and 0.2% of isolates were MDR and XDR, respectively and these percentages in E...

The appearance of antibiotic resistant strains of Pseudomonas aeruginosa especially pan-drug resi... more The appearance of antibiotic resistant strains of Pseudomonas aeruginosa especially pan-drug resistant (PDR) strains has caused efforts to identify alternative antibacterial methods such as phage therapy. The purposes of this study were the isolation and preparing of effective phage cocktails against antibiotic resistant strains of P.aeruginosa. Determination of acquired resistance profiles of these isolates was performed according to new definition of CDC and European Centre for Disease Prevention and Control as multidrug-resistant (MDR), extended-drug resistant (XDR) and PDR, and data were analyzed using WHONET5.6 software. The MDR, XDR, and PDR isolates were selected for finding of their specific bacteriophages from waste waters and hospital sewages. After phage investigation by plaque formation, enrichment, and staining of samples, transmission electron microscopy (TEM) microscope was used for phage morphology and their size determination. Among 96 isolates of P.aeruginosa, 2 (2...

Background: Production of β-lactamase enzymes is the most common and important mechanism of resis... more Background: Production of β-lactamase enzymes is the most common and important mechanism of resistance in Gram-negative bacteria. The objective of this study was to assess frequency of three main β-lactamase enzymes, including extended spectrum β-lactamases (ESBLs), metallo-β-lactamase (MBL), and Klebsiella pneumoniae carbapenemase (KPC) enzymes in Escherichia coli and Klebsiella spp. isolated from nosocomial and community urinary tract infections (UTI). Materials and Methods: In a cross-sectional study from March to December 2012, midstream urine samples were obtained from patients suspicious of UTI who were hospitalized or referred to Al-Zahra Hospital, Isfahan, Iran. Samples were cultured and E. coli and Klebsiella spp. were isolated. Prevalence of ESBLs, KPC, and MBLs producing E. coli and Klebsiella spp. were studied by double-disk (combined-disk), the modified Hodge test and imipenem-ethylenediaminetetraacetic acid combined disc methods respectively. In addition, their antimic...

Jundishapur Journal of Microbiology, 2016

Background: The emergence of pan-drug resistant strains (PDR) of Pseudomonas aeruginosa has led t... more Background: The emergence of pan-drug resistant strains (PDR) of Pseudomonas aeruginosa has led to renewed efforts to identify alternative agents, such as bacteriocins and bacteriocin-like inhibitory substances (BLISs). Objectives: The aims of this study were to determine the acquired resistance profiles of multidrug-resistant (MDR), extensively drug-resistant (XDR), and PDR P. aeruginosa isolates based on the revised definitions of the CDC and ECDC and to screen and characterize effective BLISs against these isolates. Patients and Materials: In a cross-sectional study, 96 P. aeruginosa strains were isolated during a 12-month period. The resistance profiles of these isolates were determined as MDR, XDR, and PDR, and the data were analyzed using WHONET5.6 software. A BLIS against the P. aeruginosa strains was characterized based on its physicochemical properties, size, growth curves, and production profiles. Results: Among the 96 isolates of P. aeruginosa, 2 (2.1%), 94 (97.9%), and 63 (65.6%) were non-MDR, MDR, and XDR, respectively, and 1 (1.1%) was PDR. The most effective antibiotics against these isolates were polymyxins and fosfomycin. A BLIS isolated from the P. aeruginosa DSH22 strain had potent activity against 92 (95.8%) of the 96 isolates. The BLIS was heat stable, (up to 100°C for 10 min), UV stable, and active within a pH range of 3-9. The activity of BLIS disappeared when treated with trypsin, proteinase K, and pepsin, indicating its proteinous nature. Based on its size (25 kDa), the BLIS may belong to the large colicin-like bacteriocin family. BLIS production started in the midexponential phase of growth, and the maximum level (2700 AU/mL) occurred in the late-stationary phase after 25 hours of incubation at 30°C. Conclusions: This BLIS with broad-spectrum activity may be a potential agent for the treatment or control of drug-resistant strains of P. aeruginosa infection.

Journal of Medical Microbiology, Apr 1, 2017

The purpose of this study was investigation of New Delhi metallo-β-lactamase (NDM) production amo... more The purpose of this study was investigation of New Delhi metallo-β-lactamase (NDM) production among gram negative bacilli. Antibiogram-Resistotyping and detection of NDM in clinical isolates of Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa and comparative evaluation of the diagnostic performance of three phenotypic methods for NDM detection considering PCR as gold standard were performed. Minimum Inhibitory Concentration (MIC) of antibiotics against NDM positive strains by E-test and clonal relationship analysis using Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction (ERIC-PCR) in these strains were determined. The most effective antibiotics against K.pneumoniae strains were Colistin, Chloramphenicol and Tigecycline; against P.aeruginosa were Fosfomycin and Polymyxins and against A.baumannii were Polymyxins, Ampicillin/sulbactam and Minocycline. Overall, 66, 31 and 40 different resistotypes were observed among K.pneumoniae, A.baumannii and P.aeruginosa strains, respectively. The blaNDM-1 gene was detected in 28 (8.5%) strains of investigated bacteria. Sensitivity and specificity of Meropenem-EDTA Combined Disk Test, Meropenem-Dipicolinic acid Combined Disk Test and modified hodge test (MHT) methods for NDM detection were 96.43, 55.15; 96.43, 54.85; and 89.29, 35.15 respectively. Additionally, in spite of low positive predictive values (PPV) of these tests, their negative predictive values (NPV) were high. ERIC-PCR results revealed 2 main clusters in NDM positive P.aeruginosa and A.baumannii strains each and 10 main clusters in K.pneumoniae. In all NDM-positive strains maximum MIC rates (&amp;amp;amp;gt;256) were observed for all beta-lactam antibiotics. Here, high levels of antibiotic resistance and high frequency of MDR and XDR profiles as well as high prevalence of blaNDM-1 in investigated bacteria.

American Journal of Gastroenterology

Journal of Research in Medical Sciences, Mar 1, 2014

The impact of ESBL detection is important both from a therapeutic point of view and for infection... more The impact of ESBL detection is important both from a therapeutic point of view and for infection control purposes. The fi rst ESBL was detected in Germany in 1983, among diff erent enterobacterial isolates recovered patients hospitalized at intensive care unit. [4] It was recognized by the producer strains unusual resistance to cefotaxime (CTX) and ce azidime (CAZ), which was transferable by conjugation to E. coli. Very soon afterwards in France, in 1984, Klebsiella pneumoniae isolates with an identical phenotype were detected in diff erent hospitals. [7] Carbapenems, for example, imipenem (IPM) and meropenem (MEM), are o en used to treat infections caused by ESBL producing E. coli and Klebsiella. [8,9] However, carbapenemases enzymes recognize almost all hydrolysable β-lactams, and most are resistant to Background: Production of β-lactamase enzymes is the most common and important mechanism of resistance in Gram-negative bacteria. Th e objective of this study was to assess frequency of three main β-lactamase enzymes, including extended spectrum β-lactamases (ESBLs), metallo-β-lactamase (MBL), and Klebsiella pneumoniae carbapenemase (KPC) enzymes in Escherichia coli and Klebsiella spp. isolated from nosocomial and community urinary tract infections (UTI). Materials and Methods: In a cross-sectional study from March to December 2012, midstream urine samples were obtained from patients suspicious of UTI who were hospitalized or referred to Al-Zahra Hospital, Isfahan, Iran. Samples were cultured and E. coli and Klebsiella spp. were isolated. Prevalence of ESBLs, KPC, and MBLs producing E. coli and Klebsiella spp. were studied by double-disk (combined-disk), the modifi ed Hodge test and imipenem-ethylenediaminetetraacetic acid combined disc methods respectively. In addition, their antimicrobial susceptibility patterns determined and resistant to carbapenem drugs confi rmed by minimum inhibitory concentrations based on E-test method. Results: A total of 1080 E. coli and 484 Klebsiella strains were isolated during study period. Among 720 E. coli and 384 Klebsiella isolates from hospitalized patients, 300 (41.7%) and 198 (51.5%) were ESBLs producers, respectively. In outpatients samples, the rate of ESBLs production was 25% (90/360) and 40% (40/100) in E. coli and Klebsiella isolates, respectively. Prevalence of MBLs producing in hospital E. coli and Klebsiella isolates were 0.3% (2/720) and 2.6% (10/384), and for KPC data were 1.4% (10/720) and 48.4% (186/384), respectively. No MBLs and KPC producing isolate was seen in non-hospital E. coli and Klebsiella isolates except for one non-hospital KPC producing Klebsiella isolate. Conclusion: Th e result of our study showed high prevalence of ESBLs and KPC, but low prevalence of MBLs in cultured bacteria from urine samples of patients with acute UTI. In addition, KPC was the main carbapenem resistance mechanism in Klebsiella and E. coli isolates.

Bacterial infections are one of the important agents in the creation of gallstones in the gallbla... more Bacterial infections are one of the important agents in the creation of gallstones in the gallbladder. In recent years the spread of antibiotic-resistant bacteria such as extended-spectrum β-lactamases (ESBL) is increasing and of concern in hospitalized patients worldwide. The purpose of this study was to investigate the antibiotic susceptibility patterns of isolated bacteria from the bile specimens of patients with chronic and acute cholecystitis who had been operated by single-incision laparoscopic cholecystectomy (SILC) in Isfahan (Iran) using an antibiogram susceptibility test and molecular technique. The bile fluids of 91 patients were obtained from the Al-Zahra hospital and were cultured on specific media for the isolation of Gram-negative and positive bacteria and the disk diffusion test was done to determine the antibiotic susceptibility patterns of isolated bacteria. Finally, bacterial DNA was extracted from the bile samples and polymerase chain reaction (PCR) was performed to investigate extended-spectrum β-lactamases genes. The bacteria Escherichia coli, Klebsiella pneumoniae, Proteus spp. and Staphylococcus aureus were detected in bile specimens cultured with high frequency, and the results showed that biliary infection increased with aging in patients with gallstone disease operated by SILC. The results showed a high frequency of ESBL genes including TEM, SHV, and CTX-M in isolated bacteria (especially Escherichia coli and Klebsiella spp.). Thus, evaluating the antibiotic susceptibility patterns and screening of ESBLs bacteria in patients with gallstones are essential. Prescribing suitable drugs, designing good strategies, and informing the medical community could decrease bile infection and antibiotic-resistant bacteria in clinical centers and hospitals.

Journal of Research in Medical Sciences, Mar 6, 2014