فهرست مطالب

Jundishapur Journal of Microbiology - Volume:11 Issue: 1, 2018
  • Volume:11 Issue: 1, 2018
  • تاریخ انتشار: 1396/11/30
  • تعداد عناوین: 8
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  • Abbas Abdollahi, Shahla Mansouri *, Jafar Amani, Mahdi Fasihi-Ramandi, Reza Ranjbar, Amir Ghasemi, Mohammad Moradi Page 1
    Background
    Brucellosis is one of the main causes of economic loss in domestic animals due to abortions and infertility. Brucella is a facultative intracellular pathogen that survives in other cell types in addition to phagocytes. T cell mediated responses are necessary to eradicate the infection due to Brucella.
    Objectives
    In this study the potential of recombinant protein rTF/Bp26/Omp31 as a novel Brucella subunit vaccine, protective efficacy, and immune response was evaluated in BALB/c mice.
    Methods
    After in silico design of rTF/Bp26/Omp31 structure, the gene was cloned and expressed in Escherichia coli BL21 (DE3). Finally, purified protein by Ni-NTA was used as immunogenic to immunized mice.
    Results
    Mice immunized with rTF/Bp26/Omp31 showed a vigorous humoral and cellular mediated immunity; results were compatible with IgG1 and IgG2a levels as well as high amounts of IFN-γ, IL-12, IL-4 and IL-10 production in immunized mice, compared with control groups (P
    Conclusions
    Statistical analyses indicate similar responses in immunized mice exposed to rTF/Bp26/Omp31, compared with B. abortus RB51 and B. melitensis Rev.1 vaccines. These results showed the potential of rTF/Bp26/Omp31 as a candidate for the development of a subunit vaccine against brucellosis.
    Keywords: Vaccine, Recombinant, Omp31 Protein, Trigger Factor (TF), Bp26 Protein, Brucella
  • Tahereh Kardooni, Mahmoud Rahdar *, Ali Teimoori, Abdollah Rafiei Page 2
    Background
    Cutaneous leishmaniasis is one of the most important tropical diseases in many parts of the world caused by two main species of parasites including Leishmania major and L. tropica in the old world. Several attempts have been made to reach an effective and reliable vaccine against the disease with a spectrum of success. Selection of an effective target for vaccination needs to recognize a protein antigen with minor diversity. Leishmania activated C kinase (LACK) antigen is one of the good targets for this purpose that needs to be evaluated for its diversity in local study areas.
    Objectives
    This study was conducted to evaluate the diversity in LACK protein among L. major species.
    Methods
    We collected 30 L. major isolates from different parts of Khuzestan province, southwest of Iran. Leishmania activated C kinase gene was selected for amplifying by PCR and sequencing.
    Results
    Phylogenetic tree showed that there is no diversity in LACK gene in this area.
    Conclusions
    Leishmania activated C kinase gene is a very conservative gene, suitable for vaccination.
    Keywords: Cutaneous Leishmaniasis, LACK Gene, Diversity, Phylogeny
  • Mahdi Akbari Dehbalaei, Shahin Najar-Peerayeh *, Mehrdad Behmanesh, Morovat Taherikalani Page 3
    Background
    Despite a relatively low virulence of Acinetobacter baumannii isolates, emerging multidrug-resistant (MDR) strains to pose a formidable threat to patients, particularly in ill patients in intensive care unit (ICU).
    Objectives
    The aim of the present study was to determine the genetic relatedness and antimicrobial susceptibility patterns in the endemic clones of A. baumannii isolated from patients in the ICU.
    Methods
    Fifty-five non-repetitive A. baumannii isolates were examined for antimicrobial susceptibility, oxacillinase genes, class 1 integrons and genetic relationships by PFGE.
    Results
    Antibiotic susceptibility testing showed that 21.8%) 12 isolates) were resistant to all tested antibiotics. Resistant to carbapenems were up to 85%. OXA-23, OXA-24 and OXA-58 genes were detected in 81.81%, 16.36% and 1.81% isolates respectively. The ISAba1 element upstream of blaOXA-51 was detected in 18 (32%) isolates, and 22 (40%) isolates had an ISAba1 insertion sequence upstream of the blaOXA-23. Integron class 1 was detected in 25 (55.5%) OXA-23 carrying isolates, 2 (22.2%) in OXA-24 positive isolates and in one OXA-58 carrying isolate. PFGE analysis resolved 50 distinct pulsotypes, Most of the isolates were scattered throughout across the dendrogram and a few grouped as clusters.
    Conclusions
    No significant association has been found between the pulsotype of each isolate and MDR patterns and the presence of carbapenemase genes, however, highly resistant blaOXA-23 gene carrying endemic clones of A. baumannii disseminated in the ICU of two hospitals. Therefore, active surveillance and health policies are urgently needed for the detection and control the dissemination of such organisms.
    Keywords: Intensive Care Unit, blaOXA, 23, PFGE, Acinetobacter baumannii
  • Kazem Abbaszadeh-Goudarzi, Ghasem Abbaszadeh-Goudarzi, Mohammad Reza Khorramizadeh, Saeid Bouzari, Sassan Rezaie, Mehdi Davari, Seyed Davar Siadat, Ladan Teimoori-Toolabi * Page 4
    Background
    Nontypeable Haemophilus influenzae (NTHi) is responsible for diseases such as otitis media, sinusitis, bronchitis, and pneumonia. Unlike H. influenzae Serotype b (Hib), there is no vaccine against diseases induced by NTHi. High molecular weight1 (HMW1), high molecular weight 2 (HMW2), and H. influenzae type a (Hia) proteins are critical protein adhesions of NTHi with the potentiality to provide the protection.
    Objectives
    The current study aimed at investigating the potential of recombinant HMW1555-914, HMW2553-916, and Hia585-705 proteins as subunit vaccines to induce immune responses after active immunization in Bagg albino (inbred research mouse strain) or Balb/c mice.
    Methods
    HMW1555-914, HMW2553-916, and Hia585-705 amplified by polymerase chain reaction (PCR) were cloned into pET28a. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and the Western blotting analysis were carried out to investigate the characteristics of proteins. Proteins were purified by Ni-nitrilotriacetic acid (Ni-NTA) as a gel matrix. Mice (Balb/c) were immunized subcutaneously with HMW1555-914, HMW2553-916, and Hia585-705 proteins, alone or in binary and ternary combinations. Eventually, specific antibody responses were evaluated by the enzyme-linked immunosorbent assay (ELISA) and serum bactericidal assay (SBA).
    Results
    Antibody responses significantly increased in Balb/c immunized by ternary combination compared with the control group. IgG1/IgG2a ratio indicated that proteins directed immune responses toward T-helper 2. Antisera produced against purified proteins in ternary combination showed the highest bactericidal activity against NTHi strains with the titer of 1:32.
    Conclusions
    The obtained results suggested that HMW1555-914, HMW2553-916, and Hia585-705 adhesins were the potential subunit vaccine candidates of NTHi and after further investigation could be considered for protection against NTHi infections.
    Keywords: Vaccines, HMW1 Protein, Bacteria, HMW2 Protein, Hia Adhesion, Recombinant Proteins, Haemophilus influenzae
  • Emmanuel Aniebonam Eze, Kolawole Jamiu Mustapha, Ifeanyi Amara Ndubuisi *, Uchechukwu Nwodo, Anthony Okoh Page 5
    Background
    The global threat of antimicrobial resistance is undoubtedly on the increase and most researches in this area have concentrated on effects of drug exposure and usage on resistance. Little attention has been given to natural environments apparently devoid of direct anthropogenic impact as possible reservoirs of drug resistance traits.
    Objectives
    This research was undertaken to determine possible similarities between drug resistance traits in species of Klebsiella and Citrobacter obtained from wild animals and 2 human groups.
    Methods
    Human samples were collected from Humans free from antibiotics (HN) and Human on antibiotics (HA) while samples from wildlife (WL) were taken from rats (Rattus spp), grasscutters (Thryonomys swinderianus), squirrels (Xerus erythropus), antelopes (Tragelephus scriptus), rabbits (Oryctolagus cuniculus), and farm lizards (Agama spp). Samples were analyzed using basic microbiological methods. The Disc diffusion technique was used for drug sensitivity testing while plasmid analysis was based on gel electrophoresis.
    Results
    Members of the genus Klebsiella isolated from HA exhibited more resistance to ampicillin (AMP) and augmentin (AUG) than those isolated from HN. However, Klebsiella isolated from HN displayed higher resistance to ceftriaxone (CTN), clarithromycin (CMN), ofloxacin (OFL), and pefloxacin (PEF) than those from HA. WL isolates were mostly resistant to AMP, CMN, and AUG, and less resistant to PEF, CTN, and ciprofloxacin. Correlation analysis of the antimicrobial resistance pattern on a 2 tailed test P ≤ 0.01 and P ≤ 0.05, revealed a high correlation (ranging from 0.715 to 0.917) among all the microorganisms from both sources. Gel electrophoretic analysis of plasmid DNA extracted from the isolates revealed the presence of a 23.1 kb plasmid DNA in 6 strains of Citrobacter and 3 strains of Klebsiella.
    Conclusions
    These results indicate that wild life may be important reservoirs of drug resistance genes and pathogens that have public health relevance.
    Keywords: Humans, Wild Life, Drug Resistance, Plasmids, Klebsiella, Citrobacter
  • Waqas Ahmed, Ke Zheng, Chang-Xian Wu, Zheng-Fei Liu * Page 6
    Background
    AbcR, as a small noncoding RNA (sRNA), is a typical example of a molecule acting on transencoded target mRNAs. It is a principal element of bacterial gene regulation, required for wild-type virulence in α-proteobacteria.
    Objectives
    The present study was conducted to determine the interaction between sRNA AbcR1 and target mRNA in Brucella melitensis.
    Methods
    Using the bioinformatics method, 7 targets were selected from the transcriptional factor and Two-component response regulators of B. melitensis. The interaction between AbcR1 and target mRNA was experimentally validated.
    Results
    The Two-plasmid superfolder green fluorescent protein (GFP) reporter system revealed that AbcR1 regulates the expression of target mRNA to perform regulatory functions. We confirmed this interaction with Western blot and quantitative real-time polymerase chain reaction (RT-PCR) analyses. Significant up/downregulation was observed, which showed that the conserved seed region of AbcR1 is responsible for regulating all the selected target mRNAs. The target mRNAs showed significant up/downregulation with an AbcR1 mutant. Point mutation in the seed regions of targets resulted in the up/downregulation of the target mRNA. Furthermore, we constructed a novel shuttle expression plasmid for gene expression, enabling stable replication in B. melitensis. We transformed the plasmids in B. melitensis 16M competent cells and observed significant up/downregulation of target mRNAs.
    Conclusion
    The present findings suggest that the conserved seed region of AbcR1 is responsible for regulating multiple target mRNAs. Transcriptional and Two-component response regulators of B. melitensis were direct targets of sRNA AbcR1.
    Keywords: Brucella, Small Noncoding RNA, Transcriptional Regulator, Two, Component Response Regulators
  • Roya Rafiee *, Fereshteh Eftekhar, Seyed Ahmad Tabatabaii Page 7
    Background
    The emergence and spread of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae are recognized as a major clinical problem and a public health challenge. Enterobacteria are transient colonizers of lungs affected by cystic fibrosis (CF). Klebsiella pneumoniae has been shown to cause chronic obstructive pulmonary infections.
    Objectives
    We aimed to determine the antibiotic resistance profile and ESBL production in K. pneumoniae isolates from Iranian patients with CF.
    Methods
    Sixteen K. pneumoniae strains were isolated from the sputum samples of 98 pediatric CF patients at Mofid children’s hospital in Tehran, Iran. Antibiotic susceptibility was determined via disc diffusion, and ESBL phenotype was detected by double disc synergy test (DDST). β-lactamase genes, including TEM, SHV, CTX-M, and OXA genes, were detected using polymerase chain reaction (PCR) and confirmed by sequencing the PCR products. Finally, genetic fingerprints of the isolates were determined via random amplified polymorphic DNA (RAPD)-PCR method.
    Results
    Ten isolates had ESBL phenotypes, all of which contained non-ESBL blaTEM-1 genes. Seven isolates harbored blaCTX-M-15 genes (ESBL genes), five of which also showed non-ESBL blaSHV-11, blaTEM-1, and blaOXA-1 genes (1 isolate with blaTEM-1 and 1 isolate with blaTEM-1 plus blaOXA-1 gene). However, PER-1 and VEB-1 β-lactamase genes were not detected. Genetic fingerprinting profiles showed heterogeneity among K. pneumoniae isolates.
    Conclusions
    This study highlights not only the presence of multiple β-lactamases, but also the carriage of ESBL blaCTX-M-15 gene among K. pneumoniae isolates from CF patients.
    Keywords: Cystic Fibrosis, ESBL, RAPD, blaTEM, blaSHV, blaCTX, M, blaOXA, Klebsiella pneumonia
  • Casmir Ifeanyichukwu Cajetan Ifeanyi *, Nkiruka Florence Ikeneche, Bassey Enya Bassey, Nazek Al Gallas, Akpa Alexander Casmir, Isu Rosemary Nnennaya Page 8
    Background

    Heat-labile (LT) and heat-stable (ST) toxin variants of enterotoxigenic Escherichia coli (ETEC) are enterotoxins associated with diarrhea among children in Abuja, Nigeria. Enterotoxigenic Escherichia coli is also known as a major etiological agent of diarrheal disease among travelers in developing countries. Continuous identification of commonly expressed bacterial components of ETEC can help extend the protective spectra of future candidate ETEC vaccines in Nigeria.

    Objectives

    This study aimed to provide new insights into the distribution patterns of enterotoxins, colonization factor antigens (CFA phenotypes), and serotypes and to determine the antimicrobial susceptibility patterns of ETEC strains from children with acute diarrhea in Abuja, Nigeria.

    Methods

    Escherichia coli strains, isolated from the stool samples of children aged 0 - 60 months, were tested via polymerase chain reaction, ganglioside GM1 ELISA assay, hemagglutination assay, HEp-2 cell adherence assay, dot blot technique, and disc diffusion method for antimicrobial resistance.

    Results

    Rnterotoxigenic Escherichia coli was detected in 16 (4.0%) out of 400 children with acute diarrhea. The toxigenic genotypes expressed by ETEC strains included LT toxin gene 6 (37.5%), ST toxin gene 6 (37.5%), and ST/LT gene 4 (25.0%). The CF phenotypes with major expression included CS2 (25.0%), CS3 (12.5%), and CFA1 (6.3%), with a probability value below 0.05 (P

    Conclusion

    Although ST and LT toxins seem to have equal distributions in the analyzed population, continuous identification of CFA phenotypes and toxins is necessary for the evaluation of ETEC vaccines in Nigeria.

    Keywords: Colonization Factor Antigens, Enterotoxigenic Escherichia coli, Enzyme, linked Immunosorbent Assay, Ganglioside GM1, Hemagglutination