فهرست مطالب

Microbiology - Volume:7 Issue: 5, Oct 2015

Iranian Journal of Microbiology
Volume:7 Issue: 5, Oct 2015

  • تاریخ انتشار: 1394/10/05
  • تعداد عناوین: 8
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  • Abed Zahedi Bialvaei, Hossein Samadi Kafil, Hamed Ebrahimzadeh Leylabadlo, Mehdi Yousefi, Mohammad Asgharzadeh, Mohammad Aghazadeh Pages 226-246
    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 resis- tance genes could be spread across other bacterial populations, detection of carbapenemase-producing organisms has become more 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 pneu- moniae, Pseudomonas aeruginosa and Acinetobacter baumannii. This study reviewed almost all papers, which conducted in the Middle East. In order to decrease the spread of resistance, the regional cooperation has been emphasized by the Middle East countries. The highest resistance, which is mediated by KPC has been observed in Afghanistan, Saudi Arabia and Jordan followed by NDM in Pakistan and OXA in Turkey and Pakistan. It is important to mention that the spread of these types have been reported sporadically in the other countries of this area. This review described the widespread carbapenemases in the Middle East area, which have been identified in an alarming rate.
    Keywords: Carbapenemase, KPC, NDM, OXA, Acinetobacter baumannii, Enterobacteriaceae, Pseudomonas aeruginosa, Middle East countries
  • Davood Kalantar, Neyestanaki, Mohammad Emaneini, Fereshteh Jabalameli, Morovat Taherikalani, Akbar Mirsalehian Pages 247-250
    Background And Objectives
    The oprD mutation and AmpC overproduction are the main mechanisms of intrinsic resistance to 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 and AmpC overproduction in a carbapenem-resistant P. aeruginosa isolated from a burn patient by phenotypic and molecular methods.
    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. The minimum inhibitory concentrations (MICs) against imipenem, meropenem and ceftazidime were 64 μg/ml, 16 μg/ml and 2μg/ml, respectively. The isolate was ESBLs and AmpC overproducer. No carbapenemase activity was detected by Modified Hodge test (MHT). This isolate was carrying only blaOXA-10. PCR amplification and sequencing of oprD performed on isolate resulted in PCR product of 2647bp. Sequence analysis of the 2647bp product revealed insertion of a sequence of 1232 bp at position 8 in coding region of oprD.
    Conclusion
    According to the results of this study, oprD mutation and AmpC overproduction can cause the main mechanism of resistance of P. aeruginosa to carbapenems.
    Keywords: ISPpu22, oprD, AmpC, Carbapenem, resistant P. aeruginosa
  • Rainak Ghaderi, Keyvan Tadayon, Pejvak Khaki, Nader Mosavari Pages 251-259
    Background And Objectives
    Some 2 million tons of chicken meat is produced by Iran per annum, positioning Iran among the top producers in the region. This study aimed to evaluate the molecular epidemiology and genetic characteristics of Sal- monella enterica Enteritidis in Iran.
    Materials And Methods
    A representative selection of isolates (n=76), initially genotyped by a 7-locus MLVA typing sys- tem, 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 MLST type. This is an intriguing observation as much more genome heterogeneity was expected considering the extent of diversity in the host and geography origin of the examined isolates. ST11, on the other hand is not exclusively found in Iran as it is reported also from Brazil, Denmark, Japan and the United States. In explanation of these observations, ST11 might stand for a single probably ancestral clone of Salmonella enterica Enteritidis successfully scattered in all these geographically diverse countries. Further global investigation covering more isolates and methods like whole genome sequencing would be advisable.
    Keywords: Salmonella enterica Enteritidis, MLST, MLVA, Genetic diversity
  • Kaveh Parvandar Asadollahi, Nader Mosavari, Mansoor Mayahi Pages 260-264
    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. Mo- lecular techniques such as restriction fragment length polymorphism and pulse field gel electrophoresis have been shown to be 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 the study. 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%) were RFLP type PI.1. This type was the most similar type to standard strain. However, all the patterns obtained in this study were different from the standard strain.
    Conclusion
    The result of this study indicate that these isolates probably are limited to Khuzestan region. We recommend DNA fingerprinting differentiation of non tuberculous Mycobacteria particularly Mycobacterium avium complex isolated from infected birds and human to possibly find source of infections.
    Keywords: Mycobacterium avium, RFLP, polymorphism, avian tuberculosis
  • Mazhar Salim Al Zoubi, Ibrahim Ali Al Tayyar, Emad Hussein, Alaa Al Jabali, Salih Pages 265-272
    Background And Objectives
    The global spread of methicillin resistant Staphylococcus aureus (MRSA) constitutes one of the most serious contemporary challenges to the treatment of hospital-acquired infections. We aimed to screen and assess the antibiotic susceptibility pattern of Staphylococcus aureus isolated from clinical specimens in local hospitals of Northern province in Jordan.
    Materials And Methods
    Staphylococcus aureus was isolated and identified using standard methods from various clinical specimens of different infected body sites from 358 patients during the period from January 2005 to November 2008.
    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 were susceptible to vancomycin (100%). They were also susceptible to chloramphenicol, linezolid, nitrofurantoin, rifampicin and teicoplanin (>80%), but showed resistance to erythromycin and penicillin.
    Conclusion
    Vancomycin was the most effective antimicrobial agent against S. aureus. We recommend regular surveillance of hospital associated infections and monitoring antibiotic sensitivity pattern and strict drug policy for antibiotics used within and outside the hospital environments.
    Keywords: Staphylococcus aureus, MRSA, MDR
  • Fahimeh Ghanbarinia, Mitra Kheirabadi, Nasrin Mollania Pages 273-280
    Background And Objectives
    Heavy metals are considered as high risk biocides due to their harmful effects on human health, the environment and other living organisms. Bacterial strains showing resistance to heavy metals has been used for removing such toxic materials from the environment. In this study we isolated and characterized a heavy metals-resistance halophilic bacterial strains from Kal shoor Jovein of Sabzevar, one of the industrial zone of Khorasan-e- Razavi province in Iran and has naturally saline oils.
    Materials And Methods
    Strain JC-66 is heavy metals-resistance halophilic bacterial strains isolated from Kal shoor Jovein of Sabzevar. The 16S rDNA gene was sequenced to identify this bacterium. The appropriate conditions for its potency to remove the lead were tested in various temprature, pH and agitation speed. The resistance mechanism of JC-66 to lead were investigated.
    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 exhibited in neutral medium (pH 7) incubation temperature 37 °C, and shaking rate of 180 rpm for JC-66. X-Ray Diffraction results also are indicative of adsorption mechanism to lead metal uptake. Plasmid extraction was performed to confirm the role of plasmids 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 an expression plasmid, and adsorption. It was concluded that JC-66 is able to be one of the best candidates to remove industrial pollution because it showed high resistance to lead.
    Keywords: Heavy metals, Halophilic Bacteria, Lead
  • Behzad Ghasemi, Ghasem Sanjarani, Zahra Sanjarani, Hamidreza Majidiani Pages 281-286
    Background And Objectives
    Bacterial resistance to antibiotics has motivated the researchers to evaluate the novel anti-bac- terial compounds such as some thiazole and imidazole derivatives. Thereby, in this work, we investigated the anti-bacterial effects 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 was utilized to measure the growth inhibition zone diameter values, and the broth micro-dilution method was applied to deter- mine the 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 the MIC 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 and Listeria monocytogenes was proven. However, its inhibition effect against Shigella dysenteriae was more than that against the others. Many in-vitro and in-vivo experiments are required to evaluate the effects of this compound on the bacteria and the human body.
    Keywords: Anti, bacterial effects, Thiazole, Imidazole
  • Mojtaba Mashhadi Mohammadzadeh, Vazifeh, Seyed Masoud Hosseini, Shamsolmoluk Khajeh, Nasiri, Shabnam Hashemi, Javad Fakhari Pages 287-293
    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, tem- perature and major nutrition to contaminate the food. The purpose of this research was to investigate numbers and the types of 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 one cm2 and one gram. The paperboard samples were randomly collected from popular confectionaries and fast food restaurants in 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 accep- tance level.
    Keywords: Paperboard, Food packaging, Bioburden, Family Bacillaceae, Bacterial contamination