Mutations in embB gene associated with resistance to ethambutol in Mycobacterium tuberculosis strains isolated from TB patients in the west of Iran (2014–15)

AbstractIntroductionMutations in embB gene, especially those in ethambutol resistance-determining region (ERDR), are known as “hot spots”. These mutations have frequently been reported in EMB-resistant M. tuberculosis isolates, using the Sequence analysis as a precise and effective method. The aim of this study was to detect mutations in embB gene associated with resistance to ethambutol in Mycobacterium tuberculosis strains isolated from TB patients in the west of Iran (2014–15).Material and methodsThis study was performed on smear-positive patients of the west side of Iran, in the TB research center located in Kermanshah city, during 2014–15. Out of 1069 strains of Mycobacterium tuberculosis, 50 strains with pulmonary TB were selected and evaluated (22 men and 28 women; aged between 23 and 86; median age: 54.5years).ResultsMutation in the embB gene was detected in all of the seven EMB-resistance isolates and five (42.71%) cases of them were MDR. The most frequent substantiation of amino acid occurred at the codon 306 in six (64.85%) of the EMB-resistant isolates. The Met306Val substitution resulting from an A→G transition was detected in three (42.85%) EMB-resistant isolates; and the Met306Ile substitution, due to a G→A transition was also detected in three (42.85%) resistant isolates. No mutations at the embB gene were detected in susceptible strains.ConclusionOur results were similar to those that were regularly reported in earlier studies. The only mutations in the EMB-resistant isolates were found in embB 306 and 406 codons. Substantiation amino acids at codon 306 were the most frequent. The data indicated that embB 306 mutations are sufficient to induce ethambutol resistance, and detection of these mutations is advisable to be considered in the development of rapid molecular tests. Sequence analysis of the ERDR in the embB gene is adequate for rapid detection of EMB resistance, and mutations in the codon 306 are good predictive markers for resistance to EMB

Prevalence of Vancomycin Resistance in Methicillin-Resistant Staphylococcus Aureus

Abstract: Background & Aims: Staphylococcus aureus is one of the most common pathogens in nosocomial infections. Vancomycin is the most important therapeutic drug of choice for treatment of infections caused by methicillin-resistant Staphylococcus aureus (MRSA) strains. Therefore, vancomycin-resistant Staphylococcus aureus (VRSA) or vancomycin-intermediate Staphylococcus aureus (VISA) strains are warnings for the medical community. The aim of this study was to evaluate the prevalence of vancomycin resistance in methicillin-resistant Staphylococcus aureus isolated from the nose of patients hospitalized in Imam Reza Hospital, Kermanshah, Iran. Methods: In the present study, 85 strains of methicillin-resistant Staphylococcus aureus were isolated from patients in Imam Reza Hospital and evaluated for vancomycin resistance with microdilution test, Epsilometer test (E-test), and polymerase chain reaction (PCR). Results: None of the strains were completely resistant to vancomycin; however, 39 strains (45.9%) were diagnosed as hetero-VRSA (hVISA) strains. Conclusion: VISA and VRSA strains were not observed in this study which is a promising finding in the treatment of clinical infections due to Staphylococcus aureus in our society. However, in our study, the prevalence of hVISA strain was 45.9%, which is perhaps a sign of the appearance of more resistant strains (VISA and VRSA) in our country in the future. Keywords: Staphylococcus aureus, Vancomycin, Nose, Methicillin, Hetero-vancomycin-intermediate Staphylococcus aureus (hVISA

Genotyping of ESBL Producing Uropathogenic Escherichia coli

Background and Objective. Urinary tract infection (UTI) is one of the most common bacterial infections in the world. Molecular fingerprinting of UTI isolates such as pulsed-Field Gel Electrophoresis using for Clonal distribution and determine of predominant type. The aim of the study was to determine genotyping of ESBL producing UPECs. Material and Methods. 200 UPEC isolates from outpatients with UTI were obtained. Antimicrobial susceptibility and interpretation were performed by disk diffusion. Virulence factors for UPECs were screened by using PCR. UPECs were analyzed by Pulsed-Field Gel Electrophoresis and images analyzed by Phoretix1DPro software. Results. A total of 200 isolates of UPECs, 24.5% (n=49) of isolates, were positive for ESBL production. Resistance ranged from 0% for amikacin and imipenem to over 93.9% for carbenicillin and ampicillin. Frequencies of haemagglutination, haemolysin, and hydrophobicity were 51%, 18.3%, and 14.28%, respectively. A total of 10 different genotypes were obtained, which include nine common clones and one single clone. Conclusion. We confirmed the prevalence of virulence phenotyping especially Haemagglutination among UPEC strains and that it can also contribute to virulence in these strains. Large diversity in genotypes was observed in the isolates that could be indicative of different sources of infection in community acquired

Rapid and simultaneous genotypic detection of Rifampin-Isoniazid and Ethambutol resistant Mycobacterium tuberculosis by use of MAS-PCR

AbstractAims and objectivesThis study aims to identify common mutations leading to Isoniazid (INH), Rifampin (RMP) and Etambutol (EMB) resistance using Multiplex Allele-Specific Polymerase Chain Reaction (MAS-PCR).MethodIn a cross-sectional study during 2012–2013, 257 patients with smear-positive pulmonary tuberculosis residing in five frontier west and north-west provinces of Iran were evaluated in respect of common point mutations leading to resistance to tree first-line drugs.ResultsThe overall frequency of mutations was 37 out of which 8 mutations were related to katG 315, 26 mutations pertained to rpoB 516, 526 and 531 and 3 mutations related to emb B. The rpoB single, double and triple mutations were found in 45.3%, 42.3% and 15.4% of rpoB, respectively. Frequency of patients with mutation to katG and at least one rpoB codon was 7cases (2.7%) at the same time. In this study 60.0% of INH-resistant and 83.3% of RMP-resistant isolates were detected by MAS-PCR technique. Mutation odds were higher in females and in patients with a history of anti-TB drug use.ConclusionThe MAS-PCR is a relatively rapid, sustainable, efficient and accurate technique for detection of drug resistance in tuberculosis. This highlights also the role of mutation at inhA, ahp and oxy R genes in the creation of IHN resistance which may be the causative factor in the remainder of cases

The Antimicrobial Activity of Different Extracts from Echinophora platyloba DC.

Background and Aim: Echinophora platyloba DC (Apiaceae) is a plant endemic to Kurdistan province of Iran. Aerial part of the plant is regarded as the source of natural antimicrobial agent. Materials and Methods: The aerial part of E. platyloba was extracted with hexane, dichloromethane, acetone EtOH and EtOH: H2O respectively. The extracts were individually tested against three gram-negative (Escherichia coli, Shigella flexneri, Acinetobacter baumannii) and two gram-positive bacteria (Staphylococcus aureus, Enterococcus faecalis) via agar dilution methods. Results: The best inhibitory effect was observed in ethanolic extract, which had a remarkable inhibitory effect on all bacteria especially on S. aureus. The results also indicated that dichloromethane extract showed the weakest inhibitory effect on all types of bacteria. Meanwhile, acetone extract exhibited a relatively mild inhibitory effect. Conclusion: The antimicrobial effects of E. platyloba confirmed its potential for folk use. More comprehensive investigations are recommended concerning the significant antibacterial activity of the ethanol extract of E. platyloba to determine the exact compounds responsible for observed biological activities

Genomic diversity and antimicrobial susceptibility profiling of nasal carriage Staphylococcus aureus isolated from pediatric ward in Western Iran

Nasal carriage of Staphylococcus aureus (S. aureus) probably causes the transmission of infection between individuals in hospital and community. This study aimed to evaluate the molecular epidemiology and antibiotic resistance pattern of nasal carriage S. aureus in pediatric ward patients and personnel. A total of 122 Nasal samples were taken from 28 personnel and 94 hospitalized patients in the pediatric ward. Minimum Inhibitory Concentration (MIC) to vancomycin and cefoxitin was determined by Agar dilution method strips. All S. aureus isolates were analyzed by pulsed-field gel electrophoresis (PFGE). A total of 41 S. aureus were isolated from the patients. 16 isolates (39.09%) were hospital-associated S. aureus (HA-SA) and 25 (60.97%) were community-associated S. aureus (CA-SA); also, 13 S. aureus isolates were obtained from the personnel. Based on MIC results, all of S. aureus isolates were susceptible to vancomycin, and in 41 patient isolates, 13 isolates (31.7%) were resistant to cefoxitin (MRSA). Of 13 S. aureus isolates of the personnel, 3 (23%) isolates were MRSA. Totally 11 common clones and 13 single clones were obtained. In conclusion the prevalence of CA-SA in the ward was higher than that of HA-SA. In the strains obtained from a hospital ward, there was a high epidemiology, genotypic diversity in the studied ward. However, horizontal transfer of S. aureus was observed between patients and between personnel and patients, which indicated the risk of transmission of resistant strains in the hospital wards. Keywords: Staphylococcus aureus, Nasal carriage, Pediatric ward, Antimicrobial susceptibility, Pulsed-field gel electrophoresi

Survey and typing of Pseudomonas aeruginosa strains causing nosocomial infection using multiple-locus variable number tandem repeat analysis

Background and Aim: Identification of the source of Pseudomonas aeruginosa (P. aeruginosa) as cause of nosocomial infections is an important step towards infection control. The purpose of this study was to perform multiple-locus variable number tandem repeat survey and analysis for typing of P. aeruginosa as a cause of nosocomial infection. Material and Methods: This descriptive-analytic study included 134 clinical samples of P. aeruginosa in Sanandaj from December 2015 to August 2017. Phenotypic tests and PCR were performed to confirm P. aeruginosa. Molecular typing was carried out by variable number of tandem repeats (VNTR), and analysis was performed using a zero-and-one matrix. Using Stata 12, data were analyzed by chi-square and Fisherchr('39')s exact tests (p≤0.05). Results: 41.79% of P. aeruginosa strains were associated with nosocomial infections. The highest number of clinical specimens were related to tracheal (51.78%) and the least number associated with sputum and abdominal fluid (each one1.78%). There was a significant relationship between nosocomial infections and intensive care unit (ICU) (p≤0.05). Also nosocomial infections showed a significant relationship with tracheal samples (p≤0.05). Analysis of 10 strains isolated from nosocomial infections showed 10 patterns with a similarity of 72%. Conclusion: Nosocomial infections were related to P. aeruginosa and we showed epidemiological distributions of this bacterium in our study. Identification of the origin of the bacteria responsible for nosocomial infections is an important step in the prevention and control of these infections

Antibiotic resistance in uropathogenic Escherichia coli isolated from urinary tract infections out-patients in Kermanshah

Background: Urinary tract infections (UTIs) are common cause of infections described in out-patient's setting and increase in antibiotic resistance of Escherichia coli, is encountered world-wide. Antibiotic treatment is usually empirical; therefore, this study to provide the knowledge of local resistance pathogen patterns in Kermanshah. Materials and Methods: We conducted a retrospective analysis of all E. coli isolates from urine samples admitted to Kermanshah Central lab between March 2011 and 2012 were included. Antimicrobial resistance was tested by the Kirby-Bauer disk diffusion. Results: This study showed a total of 20,742 samples, 1228 (5.92) were positive for pathogenic bacteria. E. coli were the predominant 801 isolate (65.2%). Out of the 13 antibiotics tested for E. coli isolates, minimum and maximum resistance were observed to ampicillin (9.4%) and augmentin (68.6%). Almost 59-66% of the uropathogenic E. coli strains were resistant to amikacin, co-trimoxazole, tetracycline and cephalotin and nearly half of them were resistant to nalidixic acid and cephalexin. Conclusion: This study confirms that E. coli is still the most common uropathogen isolated. Augmentin and amikacin are not as a first choice for treatment of UTI in Kermanshah area. Ampicillin and nitrofurantoin may be considered as a first choice empiric agent in out-patients

Molecular epidemiology of Mycobacterium tuberculosis isolates in Iran using Spoligotyping

Spoligotyping can help assess the transmission of Mycobacterium tuberculosis strains. We aimed to study the genotyping of M. tuberculosis isolated from patients with tuberculosis from the west of Iran by spoligotyping. Forty-seven M. tuberculosis isolates were collected from the west of Iran. All samples were cultured on Löwenstein-Jensen medium incubated at 37°C for 8 weeks. Bacterial isolates were identified as M. tuberculosis using standard biochemical tests. Drug resistance patterns of M. tuberculosis to rifampicin and isoniazid were determined, and multidrug-resistant (MDR) strains were isolated. After DNA extraction, spoligotyping was performed. We found new spoligotypes 4162 and 4163, which correlated with atypical lineage. Atypical and unknown lineages also had correlations with the MDR tuberculosis rate (4%). The most prevalent spoligointernational types were orphan (34%), 2669 (23.4%) and 127 (14.8%) types. The most prevalent clades were Ural-2 (NEW-1) (25.53%) and atypical (23.40%) lineages. The predominant clade was Ural-2 (NEW-1) and an atypical lineage restricted to Iran. The rate of MDR was low. Knowledge of the circulating isolates in the west of Iran will help implement control programmes, so knowledge of the dynamic transmission of local isolates is crucial. Keywords: Epidemiology, Iran, Molecular, Mycobacterium tuberculosis, Spoligotypin