فهرست مطالب

Infection, Epidemiology And Medicine - Volume:2 Issue: 1, 2016
  • Volume:2 Issue: 1, 2016
  • تاریخ انتشار: 1395/02/20
  • تعداد عناوین: 8
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  • Ahmad Rahmati, Jon S. Brazier Pages 1-3
    Background
    Fusobacterium necrophorum as a non-spore-forming Gram-negative anaerobic bacillus is an important human and animal pathogen. It may cause severe systemic infections (Lemierre's syndrome) and some other infections. The aim of this study was to subtype Fusobacterium necrophorum by using PCR methods.
    Materials And Methods
    Twenty five strains of Fusobacterium necrophorum subspecies funduliformis were used. Extraction of DNA and typing of the strains using REP-PCR, ERIC-PCR and BOX-PCR were done.
    Results
    Molecular typing of Fusobacterium necrophorum using REP1-R-I and REP-2-I primers generated 2 to 5 amplicons ranging in size from 1500bp to 2000bp. GelCompar comparison of banding patterns revealed seven distinct ribotype strains from 25 strains tested of which most were 2 and 4 with 8 and 7 strains respectively. BOX-PCR subtyping generated 2 to 7 comparable amplicons ranging in size from approximately 600bp to more than 2000bp. ERIC-PCR subtyping generated 6 to 11 amplicons ranging in size from approximately 100bp to 1500bp.
    Conclusions
    F. necrophorum strains have genomic variations that suggest they are never truly clonal in nature, or they may have undergone localized genetic variation across worldwide. This study also showed subtypes existing in Fusobacterium necrophorum species. We have demonstrated that Fusobacterium necrophorum REP-PCR types can be divided into seven, three subtypes by BOX-PCR and six subtypes by ERIC-PCR. BOX-PCR typing proved to be the most discriminatory method, yielding two-seven major bands. The sample size was too small to interpret statistically.
    Keywords: Typing, Fusobacterium necrophorum, PCR
  • Zoha Tavakkoliamol, Ali Nazemi, Mohammad R. Khatamnejad Pages 4-7
    Background
    Tuberculosis is one of the infectious diseases worldwide that has resurgence by the AIDS epidemic and led to the rise of drug-resistant tuberculosis patients. Thus, it seems essential to monitor the drug susceptibility in tuberculosis patients. The new High Resolution Melting (HRM) method is simple, rapid and inexpensive for detection of the mutations responsible for drug resistance in Mycobacterium tuberculosis isolates. In this study, we used HRM method to detect mutations in samples collected from tuberculosis patients.
    Materials And Methods
    Three thousand sputum samples were collected from patients with suspected tuberculosis referred to Iran Remedial Center over a period of 2 years, out of which 2000 samples were found positive for M. Tuberculosis on direct smear. After extraction of genomic DNA from sputums, HRM method was used to detection of mutations in katG and inhA genes.
    Results
    Our findings showed that 120 out of 2000 positive smear samples were resistant to isoniazid due to mutations in katG and inhA genes, out of which, 25 mutation was found in inhA gene and 95 mutation in katG gene.
    Conclusion
    The HRM method is quick, easy and affordable without need of culture and any post PCR process for diagnosing of drug resistance in tuberculosis clinical samples.
    Keywords: Mycobacterium tuberculosis, Isoniazid, High Resolution Melting
  • Shiva Modirrousta, Reza Shapouri, Sama Rezasoltani, Hamed Molaabaszadeh Pages 8-10
    Background
    Campylobacter spp. are the common pathogens that infect human beings via food. These bacteria are vibrio and have been implicated in abortion. Serotyping is the best way for typing with Penner scheme. C. jejuni and C. coli have 65 serotypes. C. coli is common in birds and dogs. Due to high rate of prevalence of Campylobacter in red-meat, chicken-meat and egg-shell, a suitable method to detect their prevalence, the most common species and serotyping group was necessary. This article describes the prevalence of Campylobacter infection, common serotyping group in 330 samples of red- meat, hen-meat and egg-shell.
    Materials And Methods
    With three
    Methods
    enrichment, selective Preston and Skirrow and filtration with membrane filters Campylobacter swere incubated. Bacterial species were identified with physiological and biochemical tests. Penner serotyping was defined with reference antiserum Ag-O and direct agglutination.
    Results
    Prevalence of Campylobacter infection was 21(23%) in red meat, 33(27.5%) in hen meat and 38(31.6%) in eggshell. In egg-shell samples: C. jejuni 20, C. coli 14, C. lari 3 and C. concisus 1 case. In meat common Penner serotyping for C. jejuni O2 had the highest rate. In hen, common Penner serotyping: for C. jejuni O3 and in egg-shell for O1, O2 and O3 had the highest rate.
    Conclusion
    Most infection of campylobacter was found in egg-shell; most common species in these three samples were C. jejuni, then C. coli and C. lari. No C. consicus was found in meat but it was found in hen and egg-shells. In common Penner serotyping for C. jejuni O2 and O3 were the most common and for C. coli in meat O49 and in hen and eggshell O5 were the highest.
    Keywords: Campylobacter, Serotyping, C. jejuni, C. coli
  • Mehdi Ghasemi, Keyvan Radjabalizade, Kia Gharari, Hashem Yaghoobi, Daryush Asgarpoor Pages 11-14
    Background
    Most of the population in the different areas of world is affected by bacterial infections responsible for dental caries. Due to the importance of traditional medicines derived from herbs used for dental problems, this study investigated in vitro antibacterial activity of Mentha longifolia essential oil from Ardabil, Iran, on Streptococcus mutans, Lactobacillus rhamnosus and Actinomyces viscosus,bacteria that cause tooth decay.
    Materials And Methods
    The volatile oil of Mentha longifolia leaves was extracted by hydrodistillation method using a Clevenger-type apparatus and analyzed by GC and GC/MS system.The antibacterial activity was evaluated by the disk diffusion susceptibility in dilutions of 62.5, 125, 250, 500, 1000 and 2000μg/μl and broth macrodilution test methods.
    Results
    The oil was particularly rich in Pulegone (31.78%), 1,8-cineole (15.99%), menthoforan (11.25%), cis-isopulegon (10.5%) and paramenth-3-n-8-l (6.85%). The medicinal plant essential oil could prevent the growth of the bacteria, and the rates of MIC and MBC of native pennyroyal essential oil on Streptococcus mutans, Lactobacillus rhamnosus and Actinomyces viscosus were 110, 165, 80, 120, 450 and 650μg/μl, respectively. The maximum inhibition zone diameter was about 12.2, 27.2 and 4.8 mm, for Streptococcus mutans, Lactobacillus rhamnosus and Actinomyces viscosus respectively, at the concentration of 500μgμl-1.
    Conclusion
    In this work, the essential oil of medicinal plant containing effective ingredients could prevent the growth of bacteria and may be used as an affordable and available source for medicinal purposes.
    Keywords: Streptococcus mutans, Lactobacillus rhamnosus, Actinomyces viscosus, Mentha longifolia
  • Abdolmajid Ghasemian, Shahin Najar Peerayeh, Bita Bakhshi, Mohsen Mirzaee Pages 15-17
    Background
    Clindamycin inducible resistant Staphylococcus aureus (S.aureus) isolates can cause failure in treatment with this antibiotic. Biofilm production via polysaccharide intercellular adhesion (PIA) contributes in the colonization of S. aureus, resulting in the initiation of different diseases. The aim of this study was to detect icaADBC genes among isolates of S.aureus with inducible resistance to clindamycin.
    Materials And Methods
    A total of 209 clinical S.aureus isolates werecollected and identified by conventional phenotypic tests. Isolates with inducible resistance to clindamycin were detected by double disk diffusion test (D-Test) using clindamycin (2 μg) and erythromycin (15 μg). Oxacillin was used to detect Methicillin resistant Staphylococcus aureus (MRSA) isolates. Polymerase Chain Reaction (PCR) was performed to detect the icaADBC genes.
    Results
    The rate of clindamycin inducible resistance was 4% (n=8). All the isolates were susceptible to methicillin. Four isolates (50%) contained the whole icaADBC genes. The prevalence of icaA, icaB, icaC and icaD genes were 5 (62.5%), 4 (50%), 6 (75%) and 5 (62.5%), respectively.
    Conclusion
    The results indicate that the prevalence of icaADBC genes among clindamycin inducible resistant strains was low, and also these strains were susceptible to methicillin.
    Keywords: Staphylococcus aureus, inducible resistance, D, test, MRSA, icaADBC operon
  • Mina Boustanshenas, Majid Akbari, Niloofar Rezaie Pages 18-21
    Background
    Aeromonas spp. can cause diarrhea and various infections in humans. Access to rapid techniques with a high sensitivity and specificity is strongly needed for the identification of Aeromonas species. The aim of this study was to evaluate two different methods including API 20E bacterial identification tests and the molecular detection using PCR primers specific for 16s-rRNA and 23S-rRNA genes sequences for identification of Aeromonas spp. in stool samples from patients with diarrhea.
    Materials And Methods
    One hundred stool samples from diarrheal patients were collected. All isolates were subjected toAPI 20 E strip tests and PCR using specific primers for identification of Aeromonas spp.
    Results
    The API 20E analysis identified 2 (2.2%) isolates as Aeromonas spp. Molecular identification by aero-23S-rRNA gene confirmed the same 2 isolates as identified by the API 20E strips.
    Conclusion
    Both API 20E system and PCR method using Aero 23S-rRNA primer were found to be accurate in identification of Aeromonas spp. isolates with highconfidence.
    Keywords: API bacterial identification, Aeromonas spp, PCR
  • Fatemeh Nikoomanesh, Shahla Roudbarmohammadi, Maryam Roudbary, Mansour Bayat, Ghasem Heidari Pages 22-24
    Background
    Adhesion and biofilm formation are two important steps in Candida pathogenesis. The aim of the current study was to investigate the presence of bcr1 gene in Candida albicans (C. albicans) isolates from women with vaginal candidiasis and its impact on biofilm formation.
    Methods
    We used 50 clinical isolates which confirmed C. albicans by PCR-RFLP. Then total RNA was extracted from C. albicans isolates by glass bead and lysis buffer, and cDNA was synthesized using reverse transcriptase enzyme. RT-PCR (Reverse Transcriptase PCR) was used to evaluate the expression of bcr1 gene. Biofilm formation was evaluated in 96-well microplate and then tetrazolium reduction was assayed. All data were analyzed using t-test by SPSS software.
    Results
    Fifty clinical isolates out of 150 were confirmed as C. albicans by using PCR-RFLP method. All the isolates were resistant to fluconazole, 47/50(94%) isolates had bcr1 gene by using PCR, and 45(95.7%) out of 47 isolates, showed BCR1 expression by the RT-PCR. Isolates which harbored bcr1 gene was succeed to form a dense biofilm on microplate. Comparison of the results of the tetrazolium reduction assay on the two isolates that had BCR1expression and two isolates that had no BCR1 expression showed significant differences (p=0.014).
    Conclusion
    According to our result, all of the isolates that had bcr1 gene expression according to RT-PCR, were also resistant to fluconazole in disk diffusion test and additionally, their adherence was higher compared to the control group. These results indicate that there is a positive relation between expression of bcr1 gene and biofilm formation.
    Keywords: Candida albicans, bcr1 gene expression, RT, PCR
  • Klrissa Streeter, Mohammad Katouli Pages 25-32
    The genus Pseudomonas consists of more than 120 species that are ubiquitous in moist environments such as water and soil ecosystems and are pathogenic to animals and humans. Within the genus of Pseudomonas, P. aeruginosa is most frequently associated with human infections. The bacterium is regarded as an opportunistic pathogen, primarily causing nosocomial infections in immunocompromised patients. The existing knowledge regarding the pathogenesis of P. aeruginosa has mainly been obtained through studying clinical isolates; particularly those involved in causing chronic lung infection in cystic fibrosis patients. Nosocomial infections commonly associated with P. aeruginosa include ventilator-associated pneumonia, catheter-associated urinary tract infections, wound infections in severe burn patients and septicaemia with their pathogenesis shown to be multifactorial. The bacterium is also capable of producing a number of toxins via the type III secretion system, as well as secreting enzymes and proteins including elastase, phospholipase C and siderophores. However, P. aeruginosa is also a waterborne pathogen, commonly found in environmental waters as well as in other sources such as sewage treatment plants. The public health implication of these bacteria whilst in the environment has not been fully investigated. Here we review our present knowledge about the pathogenesis of P. aeruginosa in clinical settings and the environment.
    Keywords: Pseudomonas aeruginosa, Virulence factors, Pathogenesis