Iranian Journal of Microbiology
Year:2015 | Volume:7 | Issue:5|Papers Count:8

Background and Objectives: Bacterial resistance to antibiotics has motivated the researchers to evaluate the novel anti-bacterialcompounds such as some thiazole and imidazole derivatives. Thereby, in this work, we investigated the anti-bacterialeffects of one new thiazole and two new imidazole derivatives on Bacillus cereus, Listeria monocytogenes, Escherichia coli, Salmonella typhimurium, Proteus mirabilis and Shigella dysenteriae.Materials and Methods: The thiazole and imidazole derivatives were dissolved in DMSO. The disk diffusion method wasutilized to measure the growth inhibition zone diameter values, and the broth micro-dilution method was applied to determinethe minimum inhibitory concentration (MIC) values.Results: The synthesized imidazole derivatives lacked any inhibitory effect against the tested bacteria. On the other hand, although the synthesized thiazole derivative showed no inhibitory effect against Bacillus cereus, Salmonella typhimurium, and Escherichia coli, it inhibited the growth of Proteus mirabilis, Shigella dysenteriae, and Listeria monocytogenes with theMIC values of 1000, 125, and 1000 μg/ml, respectively, and the growth inhibition zone diameter values of 9.3 ± 0.1, 15.6 ±0.2, and 8.1 ± 0.0 mm, respectively.Conclusion: The anti-bacterial effect of the synthesized thiazole derivative on Shigella dysenteriae, Proteus mirabilis andListeria monocytogenes was proven. However, its inhibition effect against Shigella dysenteriae was more than that againstthe others. Many in-vitro and in-vivo experiments are required to evaluate the effects of this compound on the bacteria andthe human body.

Background and Objectives: The global spread of methicillin resistant Staphylococcus aureus (MRSA) constitutes one ofthe most serious contemporary challenges to the treatment of hospital-acquired infections. We aimed to screen and assessthe antibiotic susceptibility pattern of Staphylococcus aureus isolated from clinical specimens in local hospitals of Northernprovince in Jordan.Materials and Methods: Staphylococcus aureus was isolated and identified using standard methods from various clinicalspecimens of different infected body sites from 358 patients during the period from January 2008 to November 2012.Results: Our analysis showed that 31.6% of S. aureus infections were MRSA, while 31% were multidrug resistance (MDR)and 42.7% were Oxacillin-resistant (ORSA). Most of these strains were isolated from wound specimens. All isolates weresusceptible to vancomycin (100%). They were also susceptible to chloramphenicol, linezolid, nitrofurantoin, rifampicin andteicoplanin (>80%), but showed resistance to erythromycin and penicillin.Conclusion: Vancomycin was the most effective antimicrobial agent against S. aureus. We recommend regular surveillanceof hospital associated infections and monitoring antibiotic sensitivity pattern and strict drug policy for antibiotics used withinand outside the hospital environments.

Background and Objectives: Some 2 million tons of chicken meat is produced by Iran per annum, positioning Iran amongthe top producers in the region. This study aimed to evaluate the molecular epidemiology and genetic characteristics of Salmonellaenterica Enteritidis in Iran.Materials and Methods: A representative selection of isolates (n=76), initially genotyped by a 7-locus MLVA typing system, was examined by the standard MLST genotyping.Results and Conclusion: All the MLVA typed isolates, classified into six types, were gathered under a single ST11 MLSTtype. This is an intriguing observation as much more genome heterogeneity was expected considering the extent of diversityin the host and geography origin of the examined isolates. ST11, on the other hand is not exclusively found in Iran as it isreported also from Brazil, Denmark, Japan and the United States. In explanation of these observations, ST11 might standfor a single probably ancestral clone of Salmonella enterica Enteritidis successfully scattered in all these geographicallydiverse countries. Further global investigation covering more isolates and methods like whole genome sequencing would beadvisable.

Background and Objectives: Paper and paperboard packaging play an important role in safety and quality of food products.Common bacteria of paper and paperboard food packaging could grow due to specific conditions included humidity, temperatureand major nutrition to contaminate the food. The purpose of this research was to investigate numbers and the typesof bacteria in the food packaging paperboard.Materials and Methods: The surface and the depth of the each paperboard sample were examined by the dimension of onecm2 and one gram. The paperboard samples were randomly collected from popular confectionaries and fast food restaurantsin Tehran, Iran.Results: The results indicated the range of 0.2×103 to>1.0×105 cfu/1g bacterial contamination in paperboard food packaging.Also, most detected bacteria were from spore forming and family Bacillaceae.Conclusion: The bioburden paperboard used for food packaging showed high contamination rate more than standard acceptancelevel.

Background and Objectives: Heavy metals are considered as high risk biocides due to their harmful effects on humanhealth, the environment and other living organisms. Bacterial strains showing resistance to heavy metals has been used forremoving such toxic materials from the environment. In this study we isolated and characterized a heavy metals-resistancehalophilic bacterial strains from Kal shoor Jovein of Sabzevar, one of the industrial zone of Khorasan-e- Razavi province inIran and has naturally saline oils.Materials and Methods: Strain JC-66 is heavy metals-resistance halophilic bacterial strains isolated from Kal shoor Joveinof Sabzevar. The 16S rDNA gene was sequenced to identify this bacterium. The appropriate conditions for its potency toremove the lead were tested in various temprature, pH and agitation speed. The resistance mechanism of JC-66 to lead wereinvestigated.Results: JC-66 is a Comamonas sp. according to 16S rDNA sequence analysis. Based on minimum inhibitory concentration(MIC) results, the isolated strain has high resistance to the lead metal. The optimal condition for lead removal was exhibitedin neutral medium (pH 7) incubation temperature 37oC, and shaking rate of 180 rpm for JC-66. X-Ray Diffraction resultsalso are indicative of adsorption mechanism to lead metal uptake. Plasmid extraction was performed to confirm the role ofplasmids in bacterial resistance to lead.Conclusion: It can be concluded that the mechanism of resistance to heavy metals in the studied strain, is the result of anexpression plasmid, and adsorption. It was concluded that JC-66 is able to be one of the best candidates to remove industrialpollution because it showed high resistance to lead.

Background and Objectives: The oprD mutation and AmpC overproduction are the main mechanisms of intrinsic resistanceto carbapenems such as imipenem and meropenem in Pseudomonas aeruginosa.Materials and Methods: In this study, we investigated intrinsic resistance to carbapenems including mutation of oprD andAmpC overproduction in a carbapenem-resistant P. aeruginosa isolated from a burn patient by phenotypic and molecularmethods.Results: In our study, the carbapenem-resistant P. aeruginosa isolate was resistant to imipenem, meropenem, cefepime, gentamicin, ceftriaxone, carbenicillin, aztreonam and ciprofloxacin but was susceptible to ceftazidime and polymyxin B. Theminimum inhibitory concentrations (MICs) against imipenem, meropenem and ceftazidime were 64 mg/ml, 16 mg/ml and2mg/ml, respectively. The isolate was ESBLs and AmpC overproducer. No carbapenemase activity was detected by ModifiedHodge test (MHT). This isolate was carrying only blaOXA-10. PCR amplification and sequencing of oprD performed on isolateresulted in PCR product of 2647bp. Sequence analysis of the 2647bp product revealed insertion of a sequence of 1232 bp atposition 8 in coding region of oprD.Conclusion: According to the results of this study, oprD mutation and AmpC overproduction can cause the main mechanismof resistance of P. aeruginosa to carbapenems.

Background and Objectives: Avian tuberculosis is one of the most important infections affecting most species of birds.Mycobacterium avium can not only infect all species of birds, but also infect some domesticated mammals.The most crucial aspect of control and eradication scheme is identification of infection sources and transmission routs. Moleculartechniques such as restriction fragment length polymorphism and pulse field gel electrophoresis have been shown tobe much more discriminatory and suitable for use in the epidemiological study.Materials and Methods: Eighty suspected pigeons to avian tuberculosis based on their clinical signs, were subjected to thestudy. Forty Mycobacterium avium subsp. avium isolates out of a total of 51 identified isolates were subjected to the test.Results: IS901-RFLP using Pvu II was successfully conducted and produced 7 patterns. The majority of isolates (60%) wereRFLP type PI.1. This type was the most similar type to standard strain. However, all the patterns obtained in this study weredifferent from the standard strain.Conclusion: The result of this study indicate that these isolates probably are limited to Khuzestan region. We recommendDNA fingerprinting differentiation of non tuberculous Mycobacteria particularly Mycobacterium avium complex isolatedfrom infected birds and human to possibly find source of infections.

The emergence and spread of carbapenemase-producing bacteria, that hydolyze most β-lactams, including carbapenems, are a major concern of public health system worldwide, particularly in the Middle East area. Since the plasmids harboring resistancegenes could be spread across other bacterial populations, detection of carbapenemase-producing organisms has becomemore problematic. These organisms produce different types of enzymes including the most prevalent types including KPC, VIM, IMP, NDM, and OXA-48. Carbapenemase producers are mostly identified among Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii. This study reviewed almost all papers, which conducted inthe Middle East. In order to decrease the spread of resistance, the regional cooperation has been emphasized by the MiddleEast countries. The highest resistance, which is mediated by KPC has been observed in Afghanistan, Saudi Arabia and Jordanfollowed by NDM in Pakistan and OXA in Turkey and Pakistan. It is important to mention that the spread of these types havebeen reported sporadically in the other countries of this area. This review described the widespread carbapenemases in theMiddle East area, which have been identified in an alarming rate.