فهرست مطالب

Jundishapur Journal of Microbiology - Volume:11 Issue: 12, Dec 2018

Jundishapur Journal of Microbiology
Volume:11 Issue: 12, Dec 2018

  • تاریخ انتشار: 1397/10/01
  • تعداد عناوین: 8
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  • ZeHui Yu , YuWei Zhang , Yi Geng*, KaiYu Wang , DeFang Chen , XiaoLi Huang , Yang Ouyang , Jing Fang , ZhiJun Zhong Page 1
    Background
    Streptococcus agalactiae is a serious zoonotic pathogen that causes disease in humans and other animals worldwide.
    Objectives
    Due to the increasing prevalence of S. agalactiae, as well as the transmission risk of S. agalactiae from animals to human, it was important to identify the serotype diversity and molecular typing population structure of S. agalactiae isolated from human, bovine, rabbit, and fish.
    Methods
    Capsular polysaccharide serotypes (CPS), multilocus sequence typing (MLST), and pulsed-field gel electrophoresis (PFGE) technologies were used to compare the genetic diversity of 56 S. agalactiae isolates from human, rabbit, bovine, and fish sources in China.
    Results
    We found that two serotypes (Ia, III) existed, with serotype Ia being the most common (85.7%). The 56 isolates were assigned to nine sequence types (STs) and seven clonal complexes (CCs) using MLST. The most common ST was ST891 (35.7%). The ST19 and ST103 were found in two different isolates, while the remaining STs were found in one isolate. A total of 18 PFGE clusters were identified, however, only cluster P was found in both human and bovine isolates.
    Conclusions
    Our findings suggest that serotypes, STs and PFGE, had no obvious correlation with particular host species. However, the similarity of genotypes of S. agalactiae isolated from different host species, speculating cross-infection possibility between them at genetic level.
    Keywords: Streptococcus agalactiae, Molecular Typing, Genetic Diversity
  • Nourin Mahmood , Sajid Ali*, Jehanzeb Afridi , Bashir Ahmad , Ijaz Ali , Fazal Jalil Page 2
    Background
    Hepatitis C virus (HCV) has been classified into seven major and more than 100 quasi species. To treat hepatitis C patients, it is important to determine the type of HCV as it has been linked with treatment duration and outcome.
    Objectives
    The objective of the study was to find out HCV major genotypes using Taqman Probe based real time PCR assay and to compare prevalence of these with previous HCV genotype distribution using other methods in Khyber Pakhtunkhwa.
    Methods
    In this study, 100 actively infected patients were selected, referred by different physicians, and genotyping was done using Sacace real time PCR based assay.
    Results
    Among 100 patients, the most abundant major genotype was HCV 3, followed by genotype 1 and the untypable while genotype 2 was scarcely found.
    Conclusions
    The existing methodology confirmed the prevalence of major genotype 3, similar to that of previous methodologies and studies, however, with a slight shift of genotype 2 distribution.
    Keywords: Hepatitis C Virus_Real Time Polymerase Chain Reaction_TaqMan_Interferon
  • Fahimeh Ranjbar Kermani , Sedigheh Amini, Kafiabad*, Kamran Mousavi Hosseini , Mahtab Maghsudlu , Zohreh Sharifi , Mohammad Ali Mansournia Page 3
    Background
    The hepatitis C virus (HCV) is a blood born virus and the major cause of liver diseases worldwide. Distribution of HCV genotypes varies depending on geographical regions and routes of infection. Knowledge regarding the distribution of HCV genotypes and related risk factors plays an essential role in the control of HCV infection in the community.
    Objectives
    The current study aimed at determining the current distribution of HCV genotypes and related risk factors among Iranian blood donors.
    Methods
    In the current analytical, cross sectional study, 106 HCV-infected blood donors with detectable HCV RNA over the country were interviewed by trained physicians through a post-donation questionnaire on demographic, medical, and risk history from November 2015 to May 2017. The hepatitis C virus genotype was determined by sequencing of a segment of non-structural 5B region in HCV genome. Penalized logistic regression model was used for statistical analysis through STATA software.
    Results
    Hepatitis C virus genotype was determined in all subjects, and the genotype 3a was the most frequent (65, 61.32%), followed by 1a (31, 29.25%), and 1b (10, 8.49%). Based on the multivariable analysis results, tattooing (adjusted odds ratio: 2.76; 95% confidence interval: 1.03 - 7.37) was associated with HCV genotype 3a.
    Conclusions
    According to the results, it seems that changes in molecular epidemiology of HCV infection and replacement of HCV genotype 1a with 3a, characterized by an increase in genotype 3a and decrease in genotype 1a have occurred over the last decade among Iranian blood donors. Tattooing was an independent risk factor for HCV infection by genotype 3a.
    Keywords: Hepatitis C Virus_Genotype_Blood Donors_Risk Factor
  • Maryam Tahmasebi Birgani , Mahdi Bijanzadeh , Hossein Ansari * Page 4
    Background
    Acinetobacter baumannii is one the most dangerous microbes that is resistant to a wide range of prescribed antibiotics, thus development of more effective approaches is urgent. Recombinant protein vaccines have been recently proposed as a safe method to cope with infectious agents. In this approach, antigenic gene of a bacterium can be cloned in an expression vector to produce recombinant protein.
    Objectives
    In this study, the prevalence of A. baumannii was determined in hospitalized samples and the antimicrobial susceptibility patterns of isolates were characterized for a variety of antibiotics. The ompA gene from resistant isolates was then amplified and cloned in an expression vector to produce the recombinant OmpA protein in Escherichia coli.
    Methods
    The clinical samples were collected from sputum, wounds, septicemia, and urinary tract infections at the intensive care unit (ICU) and different wards of hospitals and A. baumannii were identified, according to standard diagnostic tests. The antibiotic susceptibility patterns of the isolates were determined for 17 antibiotics. The ompA gene of A. baumannii was amplified using the polymerase chain reaction (PCR). The ompA-amplicon was cloned and sub-cloned in pTZ57RT and pET32a (+) vectors, respectively. Double digestion, DNA sequencing, and PCR were performed to confirm that ompA has been truly cloned. Using RT-PCR and SDS-PAGE, the expression of recombinant OmpA was assessed in IPTG-induced E. coli.
    Results
    Most of the A. baumannii were resistant to antibiotics cefepime, ceftazidime, ceftriaxone, aztreonam, amikacin, and gentamycin, and the least resistance was found towards colistin, ampicillin-sulbactam, and trimethoprim antibiotics. The ompA gene was amplified as 1112 bp amplicon, which was successfully cloned and sub-cloned in the pTZ57RT-T/A and pET32a (+) vectors. The presence of ~38 kDa band in SDS-PAGE showed that the recombinant pET32a-ompA was highly expressed in the host cells.
    Conclusions
    The obtained data showed the high resistance of A. baumannii-infected isolates to the antibiotics. Besides, successful cloning and expression of rOmpA in the cells suggests that the antigenic properties of ompA gene may be considered in future researches.
    Keywords: Acinetobacter baumannii, Antibacterial Agent, Multidrug Resistant, OMPA Outer Membrane Protein
  • Shahla Shafieenia , Jasem Saki*, Shahram Khademvatan , Parastoo Moradi, Choghakabodi Page 5
    Background
    Toxoplasma gondii has developed as an important opportunistic agent; recent acquired or reactivation of the parasite infection is a serious complication in HIV patients. Since the serological diagnosis may be unreliable in immunodeficient patients who fail to produce considerable titers of antibodies, molecular techniques are also required to detect toxoplasmosis in HIV patients.
    Objectives
    This study was aimed to compare nested PCR assay with serological technique for diagnosis and their capability in determining the prevalence of toxoplasmosis in AIDS cases from southwest Iran.
    Methods
    ELISA and PCR targeting B1 gene were used to analyze blood samples from 379 HIV-positive patients in Khuzestan province, southwest Iran. The amplicons were visualized and sequenced.
    Results
    Out of 379 serum samples, 131 (34.56%) and 11 (2.90%) were positive regarding anti-T. gondii IgG and IgM antibodies, respectively. Of these, 12 samples were IgG+IgM+. Nested PCR results showed that 64 out of 379 (16.88%) of the samples had DNA molecules of the B1 gene. Of these, 63 seropositive samples and only one seronegative specimen were positive by the molecular method. DNA sequencing confirmed these results. In IgG avidity test, 43 (32.82%) and 88 (67.17%) had antibodies indicating the acute and chronic phase, respectively. All 43 samples, with low avidity (100%) and 9 samples of 88 samples with high avidity (10.9%), were positive by molecular method.
    Conclusions
    This study showed a high prevalence of acute and chronic toxoplasmosis in HIV-positive patients and the findings suggested using IgG-avidity test in a condition where PCR testing is impossible, particularly to distinguish recently acquired infection from past infection.
    Keywords: Toxoplasmosis, HIV, ELISA, Nested PCR
  • Ali Asgari , Ramezan Ali Ataee*, Mahdi Ghorbanalizadegan , Ali Mehrabi Tavana Page 6
    Background
    Xylitol has been applied in dentistry to prevent dental caries for many years. However, it's anti-Streptococcus pneumoniae effects are unclear.
    Objectives
    The aim of this study was to determine the anti-Streptococcus pneumoniae activity of xylitol.
    Methods
    In this study, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of xylitol were determined by microdilution method and tetrazolium salt-based colorimetric (MTT) assay. The effective concentrations of xylitol in the presence and absence of fructose against growth and survival of S. pneumoniae were measured. Data were analyzed using univariate analysis and Kruskal-Wallis test.
    Results
    The results showed that 5% to 7.5% concentrations of xylitol were associated with reduced number of S. pneumoniae cells. About 80% to 100% of S. pneumoniae cells were killed under laboratory conditions after 3 to 7 hours, respectively. MIC and MBC of xylitol against S. pneumoniae were 2.5% and 7.5% after 4 hours, respectively. We found significant changes in the number of viable cells (P ≤ 0.002).
    Conclusions
    The results showed that the 5% and 7.5% concentrations of xylitol inhibit S. pneumoniae growth. However, the emergence of multi-drug resistance in S. pneumoniae has become a global concern and the S. pneumoniae 23-valent vaccine may not be able to protect against S. pneumoniae human pathogenic strains. Finding a non-related antibiotic agent may be useful for controlling S. pneumoniae infections.
    Keywords: Xylitol, Streptococcus pneumonia, Growth, MIC, MBC
  • Mahdane Roshani , Hossein Goudarzi , Ali Hashemi*, Abdollah Ardebili , Soroor Erfanimanesh , Aghil Bahramian Page 7
    Background
    The ability of extended spectrum beta-lactamases (ESBLs) production is one of the main mechanisms for the emergence of antibiotic resistance in Escherichia coli and Klebsiella pneumoniae.
    Objectives
    The aim of this study was to evaluate the occurrence of IS903, IS26, and ISEcp1 insertion elements among the CTX-M-producing K. pneumoniae and E. coli isolates from patients with leukemia in Tehran.
    Methods
    Eighty E. coli and K. pneumoniae isolates were recovered from patients admitted to hospitals of Tehran. Antibiotic susceptibility tests were performed by Kirby-Bauer disc diffusion and broth microdilution methods. Detection of ESBL producers was evaluated by phenotypic confirmatory test. The presence of IS903, IS26, and ISEcp1 insertion elements in CTX-M-positive E. coli and K. pneumoniae isolates was investigated by PCR-sequencing methods.
    Results
    The rate of resistance of 80 E. coli and K. pneumoniae isolates against the nine antibiotics was as follows: 100% to ampicillin, 15% to amikacin, 51% to ciprofloxacin, 30% to gentamicin, 58% to ceftriaxone, 10% to imipenem, 63% to cefotaxime, 51% to levofloxacin, and 55% to ceftazidime. Using phenotypic confirmatory test revealed that 51 (63.75%) isolates were ESBL producers. The prevalence of CTX-M-1, CTX-M-2, CTX-M-9, CTX-M-8, and CTX-M-25 genes was 87.5%, 13.75%, 23.75%, 10%, and 0%, respectively. IS903, IS26, and ISEcp1 elements were detected in 93.75%, 71.25%, and 100% of the isolates, respectively.
    Conclusions
    This study indicates that the high prevalence of antibiotic resistance, IS and CTX-M-producing E. coli, and K. pneumoniae isolates could be a major concern and highlights the need for infection control measures.
    Keywords: Escherichia coli, Extended-Spectrum Beta-Lactamases, Insertion Sequence, Klebsiella pneumoniae, Leukemic Patients
  • Soha El, Shaer , Shaymaa Hassan Abdel, Rhman , Rasha Barwa *, Ramadan Hassan Page 8
    Background
    Pathogenic Escherichia coli is responsible for serious diseases; i.e.: Peritonitis, colitis, and urinary tract infections (UTIs) and even cancer, resulting in human morbidity and mortality. Environmental strains are increasingly spreading through food and dairy products, contributing to the pathogenetic burden of E. coli infections.
    Objectives
    This study was performed to compare phylogeny, virulence factors, pathogenicity islands (PAIs), and pathotypes in- between clinical and environmental E. coli isolates.
    Methods
    A total of 105 clinical (72) and environmental (33) E. coli isolates were collected. All isolates were subjected to phylogenetic typing using a new quadruplex polymerase chain reaction (PCR). Wide array of virulence genes (VGs) and PAI markers were assessed for both subtypes, as well as, the distribution of different pathotypes among the phylogenetic groups.
    Results
    Seven phylogenetic groups were detected; clinical isolates were more prevalent in phylogenetic groups B2 (22.2%) and D (23.6%), whereas environmental isolates were in groups A (24.2%) and B1 (60.6%). Majority of VGs were higher in clinical E. coli isolates. Environmental isolates showed higher percentage of some other VGs including; stx2 and hlyA. PAI markers were widespread among both categories, showing high extra-intestinal pathogenic E. coli (ExPEC) PAIs combination in environmental isolates. Enteropathogenic E. coli (EPEC) was the most widespread pathotype in clinical isolates versus enterohemorrhagic E. coli (EHEC) in environmental ones.
    Conclusions
    Escherichia coli pathogenicity armoury was not only confined to clinical isolates, but to environmental ones as well. Therefore, environmental E. coli isolates can serve as reservoirs for transmission of E. coli pathogenicity.
    Keywords: Escherichia coli, Pathogenicity Islands, Virulence Factors, Polymerase Chain Reaction, Serotyping