IRANIAN JOURNAL OF MEDICAL MICROBIOLOGY
Year:2017 | Volume:11 | Issue:2|Papers Count:13

Background and Aims: Salmonellosis is one of the important infectious diseases and can be as spread disease between humans and animals that make it essential for identification and detection of Salmonella. Housekeeping genes are typically important genes which are necessary for maintenance and survival of basic cells and can be considered as a gene diagnostic screening bacterial agents. The aim of this study was analysis of Flic, Sdf1 and FljB, housekeeping genes for screening of typhimurium, infantis and enteritidis serovars isolated in Kerman’s hospitals.Materials and Methods: In a descriptive study from February 2015 to August 2015, 132Salmonella specimens were taken from patients with acute gastroenteritis referred to different medical centers and hospitals in Kerman. The specimens were transferred to microbiology laboratory for identification of Salmonella with serological and bacteriological standard methods. DNA of Salmonella genus strains were extracted by CTAB and, specific primers of housekeeping genes of Salmonella genus (invA) and typhimurium (fliC), infantis (fljB) and, enteritidis (sdfI) serotypes are used in PCR test.Results: Using PCR technique, the presence of Salmonella genus were confirmed by amplification of invA gene in 130 out of 132 specimens which are identified as a Salmonella by microbiological and biochemical methods (98%). Also results indicating the prevalence of 19% ininfantis, 22% in Salmonella typhimurium and 32% in Salmonella enteritidis.Conclusions: Results showed that the prevalence of Salmonella enteritidis is more than any other serotypes in this region, but as the global statistics, the prevalence of typhimurium and Infantisare increasing.

Background and Aims: Streptococcus pneumoniae is Gram-positive bacterium that causes pneumonia, septicemia, meningitis, otitis media, sinusitis, bronchitis, bacteremia and infectious processes is introduced. Due to the clinical importance of this bacterium and correct and timely diagnosis and separation of isolated samples from patients, this study were performed to identify and isolate strains of Pneumococcus from clinical samples by culture and PCR methods.Materials and Methods: In this study, 175 various clinical samples were collected from admitted patients in Tehran hospitals during 3 years (2013-2015), and culture and PCR methods used to isolate and identify of strains of Pneumococcus (after genome extraction and in the presence of specific primer) beside the standard strain ATCC 49619 (as control).Results: In this study, 40 strains of Pneumococcus have been identified and approved by culture and PCR methods. Amplified amplicon in this study, was a 160 bp fragment that were found in all strains of Streptococcus pneumoniae. Also, the PCR product was confirmed by sequencing.Conclusions: According to the obtained results in this study, PCR similar to culture, is a reliable method, but has been assessed relatively faster that can be used in the future to replace the old and conventional methods (biochemical tests and culture).

Background and Aims: Tuberculin skin test is a common method for diagnosis of latent tuberculosis but it has a high rate of false positivity and false negativity. In Quantiferon test, the interferon gamma secreted by lymphocytes in response to Mycobacterium tuberculosis antigens is measured. This study aimed to determine the rate of agreement between quantifier on with skin tuberculin induration in the diagnosis of latent tuberculosis in elderly.Materials and Methods: This study was carried out in 2015 on 10 elderly patients with confirmed active tuberculosis, 30 elderly patients with latent tuberculosis and 50 elderly individuals without any respiratory symptoms at Iran University of Medical Sciences, Tehran, Iran. The secretion of gamma interferon of specific T cells in peripheral blood was measured using Quantiferon test. In addition the tuberculin skin test was performed using standard methods and the skin induration was measured. By drawing the ROC curve, sensitivity, specificity, and under the curve area (AUC) was calculated interferon gamma release and tuberculin test. Results of patients and healthy people were compared with the Kruskal-Wallis test.Results: The sensitivity and specificity of gamma interferon release test for active tuberculosis in elderly patients was, 100% and 98% respectively (area under the curve 0.99) while the sensitivity and specificity of the tuberculin test was respectively 80% and 94% (area under the curve 0.89). Regarding to elderly patients with latent tuberculosis the sensitivity and specificity of interferon-gamma release test was 73% and 98%, respectively; and the sensitivity and specificity of tuberculin test in these patients was 36% and 94%, respectively.Conclusions: Quantiferon is more sensitive and specific test for diagnosis of latent tuberculosis and application of this method is more reliable for diagnosis of latent tuberculosis infection in the elderly.

Background and Aims: Mycobacterium avium subsp. paratubercuiosis (MAP) is the causative agent of paratuberculosis, also called as Johne's disease and is considered as the cause of irrecoverable economic losses in livestock industry. For the detection of the paratuberculosis, indirect ELISA has been highly considered as a simple method with high sensitivity and specificity. Accordingly, this study aims at designing a system of indirect ELISA for the detection of paratuberculosis.Materials and Methods: A total of 100 serum samples from 10 herds, in Tehran and Alborz provinces in 2015, in which paratuberculosis has been proven by culture, were selected and surveyed using the standard kit and the internal system was designed according to the standard kit. To design ELISA system, by using secretory antigens and confirmed positive and negative serum samples were used and checkerboard titration was performed. To determine the cutoff point, the results of the commercial kit were used as gold standard.Results: According to the commercial ELISA kit results (15 positive samples and 85 negative samples), the best concentration of antigen and antibody dilution were evaluated as 1.2 μg and 1.100 per well, respectively. Furthermore, the cutoff point was determined as 0.44.The sensitivity and specificity were evaluated as 70% and 100%, respectively.Conclusions: Secreted antigens in M. avium subsp. paratubercuiosis are sensitive to detect the infected animals but it is difficult to detect bacteria from feces in the early stages of disease. Therefore, by using indirect designed ELISA, it can be detected antibodies in the early stages of the disease.

Background and Aims: In the present study, we have tried to isolate an effective lytic bacteriophages on drug-resistant Escherichia coli isolated from diabetic ulcer wounds.Materials and Methods: Two E.coli strains were isolated by using standard methods from patients in Razi Hospital of Rasht. Waste water of the same hospital was used as a source for isolation of lytic bacteriophages. Agar layer method was used to isolate and plaque finding.Determination of host range of isolated phages was performed using five standard reference collection of E. coli. Finally, Transmission electron microscopy was used for morphological analysis of the isolated bacteriophages. Morphotype and family of isolated phages were determined based on Bradley recommendation and final version of International Committee on Taxonomy of Viruses (ICTV) report, respectively.Results: The results showed that the isolated bacteria were highly resistant to the antibiotics tested. Based on morphological characteristics, the separated virus belongs to siphoviridae family. Based on Bradley classification, isolated phage against strains of E.coli belongs to the morphotype B1.Conclusions: The isolated bacteriophage from waste water efficiently lysed the multiresistant strains of E. coli. Therefore, bacteriophages could potentially be used as an alternative for antibiotics for treating infections by multiresistant E. coli.

Background and Aims: Lactic acid bacteria play an important role in production and storage of fermented foods. This study aimed to evaluate the antimicrobial properties of a dominant lactic acid bacteria isolated from barley sourdough against some of foodborne indicator bacteria.Materials and Methods: In this experimental study which was conducted in 2015-2016 at Gorgan University of Agricultural Sciences and Natural Resources, after molecular identification of dominant lactic acid bacteria isolated from whole barley sourdough, antimicrobial effect of the isolate and it’s cell free culture filtrate as native and neutralized cell free culture filtrate obtained from logarithmic and stationary phases were investigated based on disc diffusion and microdilution (antibacterial effect) and overlay and agar spore spot (antifungal effect) methods. Results were also compared by the one way analysis of variance.Results: Sequencing results of PCR products lead to identification of Weissella cibaria as a dominant lactic acid bacteria isolated from whole barley sourdough. Based on the results of investigating of the antibacterial effect the highest antagonistic effect of the isolate and it’s native cell free culture filtrate obtained from logarithmic phase were observed against Bacillus subtilisthat was significantly (P<0.05) more than the other indicator bacteria. Furthermore, W.cibariaand it’s cell free culture filtrate had proper antifungal effects on Aspergillus flavus and Aspergillus niger.Conclusions: Based on the results of this study, it is possible to use W. cibaria and it’s cell free culture filtrate as bio preservative for controlling some microbial indicators in food and medical industries.

Background and Aims: Candida, is a fungal flora in human that can be colonized on the skin and mucosal surfaces. Various factors are involved in causing disease bycandida, one of the most important of these factors, are secreted hydrolytic enzymes and aspartyl proteinase enzymes are as a potential factor, but other secretion of hydrolytic enzymes such as phospholipase and lipase are also important pathogen factors. In this study, gene expression of LIP2, LIP3and LIP5 were studied in isolated C. albicans in 100 samples from patients.Materials and Methods: A total of 100 strains of C. albicans was isolated in 2015-2016 years by morphology and molecular methods, from clinical samples. After extracting RNA from them by RNX-Plus kit, expression of LIP2, LIP3 and LIP5 genes was evaluated by using RTPCR test.Results: From 100 clinical isolates of C. albicans, LIP2 gene expressed 55%, LIP3 gene 41% andLIP5 gene 48%. Among the positive samples, 24 cases (33.80%) were expressed three genes at the same time.Conclusions: In this study, frequency of lipase genes was different in strains of C.albicans. Lipase gene was not expressed in 30% of cases. It can be concluded that other genes than lipase gene can be involved in the pathogenesis.

Background and Aims: In this research, we present a three-component method for the preparation of 3, 4-dihydropyrano [c] chromene derivatives in the presence of ammonium trifluoroacetate. All the compounds were evaluated for their in vitro antimicrobial activity against different bacterial strains. Antibacterial behavior of product was studied based on reference Gram-positive and Gram- negative bacteria.Materials and Methods: 3, 4-Dihydropyrano [c] chromenes were synthesized using an efficient condensation of 4-hydroxycoumarin, aryl aldehydes and malononitrile catalyzed by ammonium trifluoroacetate. Different concentrations of analogs and positive control drugs were prepared in DMSO. Inoculums and sterile water were added to the fourteen test tubes each containing 1 mL of test solution at different concentrations. The tubes were incubated for 24h at 37oC. After the incubation time, the antimicrobial activity was carefully evaluated.Results: In an optimized reaction condition, the products 4a-j were obtained in high yields under reflux conditions. The antimicrobial screening data revealed that the compounds 4b and 4e have shown good activity against Gram-negative Escherichia spp.Conclusions: Present methodology offers several advantages such as short reaction time, simple procedure with an easy work-up and mild reaction conditions. We anticipated that the present method will receive the attention of medicinal chemists and be used for elaborate synthesis and pharmaceutical screening of chromenes based molecules.

Background and Aims: Acinetobacter baumannii is one of the most important opportunistic pathogen that is responsible of nosocomial infections, especially in intensive care units (ICUs). The prevalence of antibiotic resistantA. baumannii is increasing in world, and this may cause significant clinical problems. Therefore, this study aimed to evaluate the rate of antibiotic resistance of A. baumannii using meta-analysis.Materials and Methods: Information for this study obtained by searching on data bases included: Scopus, PubMed, ISI Web of Science, ISC, SID and Google Scholar by independent researchers using standard keyword and without time limit. Then studies containing inclusion criteria were evaluated. The data were analyzed by using random effects model Meta-analysis method and with the software STATA Ver.12.0.Results and Conclusions: 11 studies were eligible. This studies were analyzed for antibiotics included: cefotaxime, ceftazidime, amikacin, gentamicin, ciprofloxacin and imipenem, based on random effect models. The highest and lowest resistances were found against cefotaxime and imipenem, respectively. This study showed thatA. baumannii strain’s have resistance to a wide range of antimicrobial agents. According to the importance of these bacteria in nosocomial infections particularly in intensive care units, it is necessary to apply appropriate strategies to control the spread of this bacteria.

Background and Aims: Extended-spectrum b-lactamases are groups of enzyme with the capability of hydrolyzing cephalosporins and aztreonam. Various types of extended-spectrum b-lactamases (ESBLs), such asblaTEM and blaSHV are present prominently in E. coli strains. This study aimed to determine the frequency of blaTEM and blaSHV genes in the extended-spectrum b-lactamases, producing E. coli strains from urinary tract infections in Karaj city.Materials and Methods: In this study which performed during the summer of 2015, antibiotic susceptibility pattern of 119 isolated E. coli strains from urinary tract infections were determined to 16 different antibiotics using Kirby-Bauer disk diffusion method. Extended spectrum b-lactamases-producing bacteria were identified using double disc diffusion method by combination discs and were studied by using specific primers for genesblaTEM and blaSHV.Results and Conclusions: The highest and lowest percentage of resistance were found to tetracycline (61%) and nitrofurantoin (8.5%), respectively.42.8% of isolates were extended spectrum b-lactamases positive. Based on the PCR results the frequency of bla TEM and bla SHV were 60.78% and 39.21% respectively and 9.32% of isolates had both genes. High levels of genesblaTEM and blaSHV resistance to third generation of cephalosporins strains considered a problem. Diagnose of extended-spectrum b-lactamases strains in clinical laboratory also should be considered and it is recommended that prescription of cephalosporins should be restricted to susceptible isolates.

Background and Aims: Helicobacter pylori infection currently become as an endemic worldwide health issue. The infection causes variety of gastrointestinal diseases. The role of blood groups is established in body’s response to microorganisms and the development of gastrointestinal disorders. This study aimed to investigate the relationship between blood groups, age and gender of Iranian population and the severity of infection with this bacteria.Materials and Methods: The study included 160 patients with dyspepsia symptoms referred to Hajar hospital in Shahrekord. Biopsy specimens were investigated in terms of being infected withH. pylori by using PCR for 16SRNA gene and glmM gene and blood groups of patients were determined by using hemagglutination routine test.Results and Conclusions: It was observed that 61.87% of patients were positive in terms of bacteria existence and 61 of them were negative.62.26% of infected patients with bacteria were female. The highest frequency of ABO blood groups among infected patients, belongs to O blood group with 40.66 percent (P>0.05).H. pylori was found in 77.12% of Rh+patients (P<0.05). There is not significant relation between sex and age with infection (p>0.05). The severity of this bacterial disease were observed in patients with blood group O more than others (P<0.05). Rh positive in infected patients and O blood group may cause to severity of H. pylori infection.