Multicentre study of the main carbapenem resistance mechanisms in important members of the Enterobacteriaceae family in Iran.

Resistance to carbapenems has been increasingly reported from the Enterobacteriaceae family, with different mechanisms in different geographic parts of the world. This study investigated the mechanisms of carbapenem resistance in Escherichia coli, Klebsiella pneumoniae and Enterobacter spp. carried out as a multicentre study (n = 10). All third-generation cephalosporin-resistant E. coli, K. pneumoniae and Enterobacter spp. that had been recovered from the selected provinces were included. Modified Hodge test and Carba NP test were done as a phenotypical method for detection of carbapenemase; the most common carbapenemase was detected by PCR. We evaluated the presence of an active efflux pump by using cyanide 3-chlorophenylhydrazone. Overexpression of AcrA/B and presence of OqxAB was detected by real-time PCR and conventional PCR respectively. Microorganisms in this study included 58 E. coli, 95 K. pneumoniae and 60 Enterobacter spp. Modified Hodge test showed a sensitivity of 41% and a specificity of 83%, and the Carba NP test showed a sensitivity of 26% and a specificity of 92% for detection of carbapenemase. OXA-48 was the most frequently detected carbapenemase, followed by NDM-1. Thirty-nine percent and 27% of positive cyanide 3-chlorophenylhydrazone test organisms included active AcrA/B and OqxAB efflux pumps respectively. The result showed the Carba NP test was more specific than MHT. Data confirmed the involvement of AcrA/B and OqxAB efflux pump as a carbapenem resistance mechanism in selected bacteria. Similar to other reports from the Middle East, we found OXA-48 and NDM-1 to be the most frequent carbapenemase.

Isolation and identification of nontuberculous mycobacteria from specimens of lower respiratory tract of transplanted patients based on the evaluation of 16SrRNA gene.

BACKGROUND: Nontuberculous mycobacteria are pervasive microorganisms and are often present as saprophytes in humans, animals, and the environment. Today, these bacteria are known as the most important environmental opportunists and, in the last decades, infections by nontuberculous mycobacteria have multiplied, due to increased immunodeficiency (cancer, transplant recipients, HIV). STUDY DESIGN: This study aimed to investigate the infections by nontuberculous mycobacteria in transplanted patients. METHODS: The study was performed on 57 samples from respiratory secretions of transplant recipients taken by standard methods. Nontuberculous mycobacteria were identified by culture method and molecular identities of clinical isolates were investigated by PCR amplification using 16SrRNA gene and sequence analysis and Blast of the sequences. Demographic data were evaluated by Spss software. RESULTS: The prevalence of nontuberculous mycobacteria in transplant patients was 22.8%, the age of patients was between 23 and 52 years. The most common involvement of nontuberculous mycobacteria in our transplanted individuals were 6 strains of M avium-intracellulare Complex (42.87%), followed by 2 strains of M marinum (14.29%) and 1 strain each (7.14%) of M xenopi, M chelonae, M intracellulare, M kansasii, M simiae. At the conclusion of the tests, one final strain was identified as M tuberculosis (7.14%). CONCLUSION: The prevalence of nontuberculous mycobacteria indicates their importance in the fate of these patients. The identification of nontuberculous mycobacteria is a neglected part of microbiology laboratories, due to the lack of sufficient facilities and the risk associated with their culture. Therefore developing routine methods for the identification of these infections appears to be critical, especially in hospitals with the transplantation ward.

Non-sterile corn steep liquor a novel, cost effective and powerful culture media for Sporosarcina pasteurii cultivation for sand improvement.

AIMS: Microbial induced calcium carbonate precipitation (MICP) is one of the bio-cementation methods for improving granular soils. This study evaluate the feasibility of obtaining a bacterial solution with high optical density and urease activity by an inexpensive corn steep liquor (CSL) medium in non-sterile conditions in order to achieve sand improvement. METHODS AND RESULTS: Corn steep liquor media with different concentrations (different dilution rates) were prepared and, without any autoclaving (non-sterile conditions), different percentage of the inoculum solutions were added to them and incubated. Effect of inoculum solution percentage and CSL dilution rates on specifications of bacterial solution was evaluated. Urease activity and scanning electron microscope (SEM) and X-Ray Diffraction (XRD) were used to efficiency of CLS media in sand improvement. The considerable urease activity was measured as 5·7 mS cm-1  min-1 using nonsterile CLS. By using CYNU (CSL-Yeast extract-NH4Cl-Urea) bacterial solution, the urease activity of 5·5 mS cm-1  min-1 for the OD600 (optical density at 600 nm) of 1·88 and, consequently, specific urease activity of 2·93 mS cm-1  min-1  OD600 -1 was obtained. The highest unconfined compressive strength (811 kPa) was obtained for the CYNU. XRD revealed new calcite peaks next to the quartz peaks. CONCLUSIONS: Production of inexpensive bacterial solution using diluted CSL as the inexpensive, effective and powerful culture media for Sporosarcina pasteurii cultivation in nonsterile conditions, allows geotechnical and biotechnological engineers to use MICP technology more widely in land improvement and field-scale bio-cementation and bioremediation projects. SIGNIFICANCE AND IMPACT OF THE STUDY: Obtaining high urease activity of inexpensive microbial solution using diluted CSL as the culture medium in nonsterile conditions, as the unique results of this study, can be significant in the field of bioremediation studies using MICP.

High rate of contamination with Staphylococcus aureus in traditional Koozeh cheeses. A molecular typing approach.

BACKGROUND: Koozeh cheese is an Iranian dairy product in rural areas, it is necessary to consider the microbial contamination in this supply. OBJECTIVE: This study evaluates microbial contamination in Koozeh cheese by molecular tools. MAATERIAL AND METHODS: S. aureus and its enterotoxins including type A and type B were identified by biochemical and polymerase chain reaction (PCR) and molecular typing was done by RAPD (Random Amplification of Polymorphic DNA) method. A total of 42 sheeps and cows Koozeh cheese samples were collected from random market in the cities and the surrounding villages. RESULTS: 71.42% of samples were contaminated with Staphylococcus spp. and in 50% of isolates, S. aureus specific coagulase gene "coa" was detected. High-level contamination was observed in 7.14% of samples. The SEA or SEB enterotoxins were produced in 42.84% of isolates. No clonal relationship was observed by molecular approach. CONCLUSION: The obtained results indicate a high level of microbial contamination in Koozeh cheese. Half of isolates were enterotoxin producer and had high diversity and no clonal relationship. Long processing and manipulation are involved in contamination. Improvement in hygiene, training local manufactures of Koozeh cheese, control of products for possible contamination and developing new protocols is needed to decrement of S. aureus contamination in Koozeh Cheese products.

Genotyping of Mycobacterium tuberculosis isolates from northwest Iran for determination on the mechanism of transmission.

Planning to control tuberculosis requires identification of dominant strains in the region, transmission patterns and risk factors that are possible by using molecular genotyping techniques. The aim of this study is to determine the transmission of tuberculosis in the northwest of Iran in order to better understand the spread of disease in northwest of Iran. In this study, 194 positive mycobacterium cultivars in northwest of Iran were investigated using exact tandem repeat-variable number tandem repeats (ETR-VNTR) method. The ETR-VNTR method was identified 55 different patterns in 194 isolates, which contained 25 clusters and 30 unique patterns, and the largest cluster had 33 isolates, and discriminatory power of ETRVNTR method was determined 0.9322 in the examined samples. There are strains of Mycobacterium tuberculosis located in the northwest of Iran that infect people, and ETRVNTR method can be used as a first-line method to examine the dynamics of tuberculosis transmission.

Genotyping of Mycobacterium tuberculosis isolates from northwest Iran for determination on the mechanism of transmission

@#Planning to control tuberculosis requires identification of dominant strains in the region, transmission patterns and risk factors that are possible by using molecular genotyping techniques. The aim of this study is to determine the transmission of tuberculosis in the northwest of Iran in order to better understand the spread of disease in northwest of Iran. In this study, 194 positive mycobacterium cultivars in northwest of Iran were investigated using exact tandem repeat-variable number tandem repeats (ETR-VNTR) method. The ETR-VNTR method was identified 55 different patterns in 194 isolates, which contained 25 clusters and 30 unique patterns, and the largest cluster had 33 isolates, and discriminatory power of ETRVNTR method was determined 0.9322 in the examined samples. There are strains of Mycobacterium tuberculosis located in the northwest of Iran that infect people, and ETRVNTR method can be used as a first-line method to examine the dynamics of tuberculosis transmission.

Thymol and carvacrol strongly inhibit biofilm formation and growth of carbapenemase-producing Gram negative bacilli.

Discovery of novel drugs with new mechanisms of action and without cross-reaction with current therapeutic agents is crucial in the management of infections caused by multi-drug resistant (MDR) bacteria. The aim of the present study was to investigate effects of carvacrol and thymol on biofilm formation and antimicrobial activity against different carbapenemase-producing Gram negative bacilli. The antimicrobial and antibiofilm effect of thymol and carvacrol was investigated against strains harboring different genes related to carbapenemase resistance. Antimicrobial resistance was examined by an agar dilution method and antibiofilm effect was evaluated by microtiter plate assay and staining by crystal violet. Thymol and carvacrol had antibacterial effects ranging from 200-1600 µg/mL and 62-250 µg/mL respectively, and antibiofilm effect from 125-500 and 400-1600 µg/mL respectively. Seoul imipenemase- (SIM) producing isolates had the highest sensitivity, and NDM (New Delhi metallo-beta-lactamase) producing isolates had the lowest sensitivity to these components. Findings of the present study indicated a potential role of carvacrol and thymol in controlling carbapenemase-producing gram negative bacterial infections. These findings helped to develop herbal drugs for replacing antibiotics. In addition, their antibiofilm effects showed that carvacrol and thymol inhibit biofilm formation of carbapenemase-producing strains.

Suppressing the CRISPR/Cas adaptive immune system in bacterial infections.

Clustered regularly interspaced short palindromic repeats (CRISPR) coupled with CRISPR-associated (Cas) proteins (CRISPR/Cas) are the adaptive immune system of eubacteria and archaebacteria. This system provides protection of bacteria against invading foreign DNA, such as transposons, bacteriophages and plasmids. Three-stage processes in this system for immunity against foreign DNAs are defined as adaptation, expression and interference. Recent studies suggested a correlation between the interfering of the CRISPR/Cas locus, acquisition of antibiotic resistance and pathogenicity island. In this review article, we demonstrate and discuss the CRISPR/Cas system's roles in interference with acquisition of antibiotic resistance and pathogenicity island in some eubacteria. Totally, these systems function as the adaptive immune system of bacteria against invading foreign DNA, blocking the acquisition of antibiotic resistance and virulence factor, detecting serotypes, indirect effects of CRISPR self-targeting, associating with physiological functions, associating with infections in humans at the transmission stage, interfering with natural transformation, a tool for genome editing in genome engineering, monitoring foodborne pathogens etc. These results showed that the CRISPR/Cas system might prevent the emergence of virulence both in vitro and in vivo. Moreover, this system was shown to be a strong selective pressure for the acquisition of antibiotic resistance and virulence factor in bacterial pathogens.

The effect of ω-fatty acids on mRNA expression level of PPARγ in patients with gastric adenocarcinoma.

BACKGROUND: The antineoplastic role of peroxisome proliferator-activated receptor gamma (PPARγ) ligandshas previously been demonstrated in several gastric cancer cell lines. Activation of PPARγ by polyunsaturated fatty acids (PUFAs) inhibits growth and proliferationof tumor cells. In this double-blind clinical study, we evaluate the effect of PUFAs on PPARγ mRNA expression in patients with gastric adenocarcinoma. MATERIALS AND METHODS: A total of 34 chemotherapy-naive patients diagnosed with gastric adenocarcinoma were enrolled in the present study. According to treatment strategies, all subjects were divided into two groups, the first group (17 individuals) received cisplatin without supplements and the second group (17 individuals) received cisplatin plus orally administered PUFAs supplements for 3 weeks. The gastric biopsy samples were obtained from all participants before and after treatment, and PPARγ mRNA expression levels were evaluated by quantitative real-time polymerase chain reaction using validated reference genes. RESULTS: Our findings revealed that PPARγ mRNA expression is significantly upregulated in group II afterreceiving cisplatin plus orally administered PUFAs supplements for three weeks (p < 0.0001), whereas PPARγ mRNA expression did not show significant alteration in group I after receiving cisplatin alone. CONCLUSION: The results of the study evidence that PPARγ may act as a potential target for the therapy of human gastric adenocarcinoma.