فهرست مطالب

Iranian Journal of Microbiology
Volume:2 Issue: 4, Dec 2010

  • تاریخ انتشار: 1389/10/11
  • تعداد عناوین: 9
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  • N. Hosseini Jazani, M. Karimzad, S. Shahabi Page 172
    Background And Objectives
    Glycoprotein 96 is the primary chaperone of the endoplasmic reticulum. Immunization with it induced potent Cytotoxic T lymphocyte responses to intracellular bacteria. S. typhimurium is a facultative intracellular bacterium and acquired resistance against this bacterium mainly depends on activity of Cytotoxic T cells. This study aimed to evaluate the capacity of Glycoprotein 96 rich lysate as a vaccine candidate to induce a protective immune response in mice against a lethal dose challenge with Salmonella typhimurium.
    Materials And Methods
    Mice were infected with S. typhimurium. Then their spleens and livers were harvested and homogenized and the protein content of whole crude lysate was enriched using ammonium sulfate precipitation. SDS-polyacrylamide gel electrophoresis transfer method was used for enrichment of the protein from crude sample. Immunoblotting was conducted to detect Glycoprotein 96. Isoelectric point was achieved through the use of isoelectric focusing. PBS and whole crude lysate (from uninfected and infected mice) were injected to mice of test group, mice of control-1 group and mice of control-2 group, respectively, on days 0 and 14. Twenty-one days after the last immunization, the LD50 and bacterial loads of livers and spleens were determined.Results and
    Conclusion
    Immunization with Glycoprotein 96 rich lysate isolated from livers and spleens of S. typhimurium-infected mice induced protection against infection by S. typhimurium. Also, the bacterial burden of livers and spleens in mice that received gp96 rich lysate significantly decreased when compared to that of mice in the control groups.
  • M. Dilmaghani, M. Ahmadi, T. Zahraei Salehi, A. Talebi Page 178
    Background And Objectives
    Economic constraint of diseases arising from Salmonella Typhimurium causes the study of this zoonotic organism more important. Most studies on identification and characterization of S. Typhimurium are conducted at DNA level. Flagellin genes (fliC and fljB genes encoding phase-1 and phase-2 flagella, respectively) are useful as a model system for studying genetic differentiation. The objectives of the present study were to identify the polymorphism of fljB among avians in different regions by the PCR-RFLP method.
    Materials And Methods
    Fifty-two S. Typhimurium isolates out of 1,870 intestine samples were identified using culture and serotyping as well as multiplex-PCR (broiler (n = 13), layer (n = 12), duck (n = 5), goose (n = 5), sparrow (n = 8), canary (n = 3), pigeon (n = 5) and casco parrot (n = 1)). Amplification of fljB gene was performed and amplified products subjected to restriction digestion with Hha I enzyme.
    Results
    Two RFLP patterns generated DNA fragments between approximately 50 to 800 bps. Pattern A was observed in 33 (63.46%) and pattern B in 19 (36.54%) of isolates. Salmonella Typhimurium recovered from 13 broilers (ten with pattern A and 3 with pattern B) and 8 sparrow (three with pattern A and 5 with pattern B) showed both A and B patterns. Twelve layers, 5 pigeons and 3 canaries showed pattern A and 5 ducks, 5 geese and one casco parrot showed pattern B. None of these patterns was allotted for a special region.
    Conclusion
    The results of the present study showed that fljB gene is highly conserved among avians in different geographical regions, suggesting not only the importance of fljB gene in survival of organism in different environmental conditions but also the relation between proteins encoded by fljB gene and serotyping scheme.
  • V. Sharma, N. Jindal, P. Devi Page 185
    Background And Objectives
    Presence of methicillin and multidrug resistance has associated coagulase negative staphylococci (CNS) with high morbidity and mortality worldwide. The present study was carried out to study the susceptibility pattern of CNS to various antimicrobial agents and to determine the prevalence of CNS methicillin resistance in our hospital setting.
    Materials And Methods
    A total of 300 strains of CNS isolated from various clinical specimens were subjected to speciation and their antimicrobial sensitivity testing was studied by Kirby Bauer disc diffusion method. Methicillin resistance was studied by observing minimum inhibitory concentration (MIC) of Oxacillin by macrobroth dilution method and E test. Susceptibility to vancomycin was determined by vancomycin screen agar test and minimum inhibitory concentration by macrobroth dilution test.
    Results
    All the isolates were susceptible to vancomycin, linezolid and teicoplanin in disc diffusion test while maximum resistance was noted against penicillin (100%) followed by ciprofloxacin (36.3%), norfloxacin (34.3%), gentamicin (34%), nitrofurantoin (29.9%), erythromycin (27.9%) and amikacin (22.7%). Fifty two percent (n = 156) of the isolates were found to be resistant to methicillin. A comparison between resistance patterns of methicilin resistant and methicillin sensitive strains showed that methicillin resistant isolates had higher level of resistance to other antibiotics.
    Conclusions
    The high level of resistance among CNS to commonly used antimicrobial agents in our hospital is a matter of great concern and can be prevented by practices of effective infection control measures.
  • M. Bolfion, M. Salehi, J. Ashrafi Helan, K. Soleimani, R. Keshavarz, R. Aref Pajoohi, M. Mohammad Taheri, K. Tadayon, N. Mosavari Page 189
    Background And Objectives
    Pigeons are extensively kept for homing and racing purposes in Iran. The main objective of this study was to investigate dissemination of M. avium subsp. avium (MAA) in pigeon aviaries in Tabriz, North-western Iran.
    Materials And Methods
    Postmortem pathologic specimens from thirty-nine out of 140 birds collected from private flocks (n = 3), were subjected to bacterial culture out of which 3-4 mycobacterial isolates were recovered.
    Results
    Applying a five-PCR diagnostic algorithm targeting short but definitive stretches of 16S rRNA and RV0577 genes, IS6110, IS901 and IS1245 genomic loci, proved all the isolates were MAA. They were either IS901+/IS1245+ (n = 22) or IS901+/IS1245- (n = 12).When four healthy cattle sensitized against Mycobacterium bovis AN5 and Mycobacterium avium D4 were tuberculinated, the results confirmed the observed skin reactions against bovine tuberculin in animals sensitized with M. avium were large enough to complicate test interpretation.
    Conclusion
    We believe the extent of such epidemiological impact deserves further investigation if progress in control of bovine tuberculosis is intended.
  • H. Goudarzi, Es Mirsamadi, S. Jahani Sherafat, M. Esfahani, N. Faramarzi Page 194
    Background And Objectives
    Phospholipase of Mycobacterium tuberculosis plays an important role in pathogenesis through breaking up phospholipids and production of diacylglycerol. In this study, we examined the Beijing strains of Mycobacterium tuberculosis isolated from Iranian patients for the genes encoding this enzyme.
    Materials And Methods
    DNA extraction was performed using CTAB (cetyltrimethylammonium bromide) from positive culture specimens in tuberculosis patients. PCR was then used to amplify the plcA, plcB, plcC genes of Beijing strain, and non-Beijing strains were identified by spoligotyping.
    Results
    Of 200 specimens, 19 (9.5%) were Beijing strain and 181 (90.5%) were non-Beijing strains. The results of PCR for Beijing strains were as follows: 16 strains (84.2%) were positive for plcA, 17 (89.4%) were positive for plcB and 17 (89.4%) were positive for plcC genes. The standard strain (H37RV) was used as control.
    Conclusion
    The majority of Beijing strains have phospholipase C genes which can contribute to their pathogenesis but we need complementary studies to confirm the role of phospholipase C in pathogenecity of Mycobacterium tuberculosis.
  • S. Haghighi Karsidani, M. Soltani, G. Nikbakhat-Brojeni, Hf Skall Page 199
    Background And Objectives
    Streptococcosis/lactococcosis is a hyperacute systemic disease that can occur in marine and fresh waters of many species of fish. The aim of this work was to study the disease outbreak in the major rainbow trout (Oncorhynchus mykiss) production of Iran.
    Materials And Methods
    108 Gram positive cocci isolates were obtained from diseased trout in seven provinces with major trout production during 2008 till 2009. These bacterial isolates were characterized using phenotypic and molecular studies. The isolates were also analysed phylogeneticaly and compared with the available data.
    Results
    49 samples (45.37%) were identified as Streptococcus iniae, 37 samples (35.2%) matched with Lactococcus garvieae; and 22 samples (19.43%) were identified as members of Streptooccus genus by culture-based and biochemical tests of API 50 CH, API 20 STREP and rapid 32 STREP systems. Using universal primers for differentiation of Streptococcus sp. and Enterococcus sp, all 108 samples were identified as Streptococcus sp. with a target region of 500 bp. Single specific PCR resulted in identification of 64 (59.2%) isolates as S. iniae and 44 (40.8%) isolates as L. garvieae. The phylogenetic analysis of the S. iniae isolates resulted in maximal similarity to some strains reported from Taiwan and to all Brazilian strains. Also, one strain showed less sequence similarity values with other tested strains although this strain has high similarity with ATCC 29178 strain, all reported Chinese, and some Taiwanian strains. Also, analysis of S. iniae LctO gene sequence showed that this isolate clustered within the S. iniae group. The sequence analysis of L. garvieae strains also showed that they have maximum similarity to all Japanese and Chinese strains, but one strain has lower sequence similarity values with all other recorded strains.Conculsion: The results of this study clearly show that trout farming in Iran is severely affected by both species of S. iniae and L. garvieae and requires serious preventive criteria.
  • R. Gopalakrishnan, S. Joseph, S. Sellappa Page 211
    Background And Objectives
    DNA ladder contains DNA fragments of different length but with known size, used to determine the size of unknown DNA molecules. Different DNA ladders are available for expected DNA length. Conserved sequences were selected for design of primers to generate DNA fragments of known specific size.
    Materials And Methods
    In this study, we describe a method by which DNA ladder was prepared based on multiplex PCR technique. Different lengths of DNA fragments were amplified using the primers designed according to the 1216-2136 sequence extent of lambda phage DNA. Target DNA fragments were amplified using multiplex PCR and extracted.
    Results
    The results showed an amplified lambda phage DNA at particular target sites by using 1 forward and 6 different reverse primers (for 100, 200, 400, 600, 800, 1000bp) for the successful amplification.
    Conclusion
    This method would be more cost effective than commercial DNA molecular weight markers.
  • K. Karthikeyan, K. Nanthakumar, K. Shanthi, P. Lakshmanaperumalsamy Page 214
    Background And Objectives
    Discharge of wastewater from textile dyeing industries has been a problem in terms of pollution and treatment of these waters is a great task. Keeping this in mind, the aim of our current research is to study the effect of various bioprocess variables on decolorization of an azo dye, Congo red, by a fungal isolate, Aspergillus niger HM11.
    Materials And Methods
    Central composite design (CCD) and response surface methodology (RSM) have been applied to design experiments to evaluate the interactive effects of the operating variables: on the decolorization of Congo red. A total of 30 experiments were conducted in the present study and a regression coefficient between the variables was generated.
    Results
    The RSM indicated that pH 6.0, 150 rpm agitation, incubation time of 36 hrs and a glucose concentration of 1.0% were optimal for maximum decolorization of Congo red and the response indicated excellent evaluation of experimental data.
    Conclusion
    From this study, it is very obvious that the fungal isolate, Aspergillus niger HM11 can be used as a promising microbial strain for decolorization of textile dyeing effluent containing similar dyes.
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