فهرست مطالب

Jundishapur Journal of Microbiology - Volume:12 Issue: 1, 2019
  • Volume:12 Issue: 1, 2019
  • تاریخ انتشار: 1397/11/06
  • تعداد عناوین: 7
|
  • Gitishree Das , Seonjoo Park , Jinhee Choi , Kwang Hyun Baek * Page 1
    Background
    Candida infection currently presents a major problem. The natural products from endophytic bacteria are thought to have a strong potential for treatment.
    Objectives
    The present study aimed to isolate endophytic bacteria from Dryopteris uniformis, its identification, and investigation of their anticandidal activity and confirm it.
    Methods
    The isolated endophytic bacteria from D. uniformis were identified by using 16S rRNA gene sequencing. The anticandidal assay of endophytic bacteria was performed by using the patch method. Endophytic bacteria were successively fractionated by using different polarity solvents. The anticandidal activity of each solvent fraction was evaluated by using the disc diffusion method and was confirmed by scanning electron microscopy.
    Results
    Fifty-one endophytic bacteria were isolated from the lead and stem/root of D. uniformis and screened for anticandidal activity against five Candida species, Candida saitoana (KACC 41238), C. albicans (KACC 30062), C. albicans (KACC 30003), C. glabrata (KBNO6P00368) and C. glochares (KACC 30061). Among these, six endophytic bacteria exhibited strong anticandidal activity with an inhibition zone diameter between 9.29 and 47.67 mm against four Candida species; these bacteria were identified as Burkholderia sp. UR 1-07 (DUS14), Staphylococcus sp. WW60 (DUS56), Bacillus sp. cryopeg (DUS59), Paenibacillus sp. rif200865 (DUL128), Staphylococcus warneri (DUS130), and Bacillus psychrodurans (DUS131) using 16S rRNA gene sequencing. The minimum inhibitory concentration (MIC) of the butanol fraction of the selected endophytic bacteria, Burkholderia sp., was 250 µg/mL and the minimum fungicidal concentration (MFC) was 500 µg/mL. Scanning electron microscopy result indicated that, MIC of promising endophytic bacteria Burkholderia sp. destroyed the target Candida cells.
    Conclusions
    This study demonstrated anticandidal potential of endophytic bacteria derived from D. uniformis.
    Keywords: Anticandidal Activity, Bacillus psychrodurans, Burkholderia sp., Candida Species, Dryopteris Uniformis, Endophytes, Paenibacillus sp
  • Hadi Peeridogaheh , Roghayeh Teimourpour , Bagher Moradi , Mehdi Yousefipour , Aida Gholoobi , Akram Baghani , Zahra Meshkat * Page 2
    Background
    Many studies indicate that the Bacillus Calmette-Guérin (BCG) vaccine has low protective efficacy, especially in endemic areas. There are several factors in this assessment, such as genetic diversity of BCG strains, pre-exposure to environmental mycobacteria, and variations in host immune responses. Currently, more than 200 new vaccine candidates have been proposed, such as recombinant BCG, DNA, and subunit vaccines. However, none of them are superior to BCG. Nevertheless, several approaches are considered to reduce the cases of tuberculosis infection.
    Objectives
    The aim of the present study was to evaluate the capability of the Ag85a-cfp10 fusion protein as a new chimeric protein in stimulating immune responses.
    Methods
    A DNA vaccine encoding Ag85a-cfp10 fusion protein was constructed in the previous study. The expression of Ag85a-cfp10 fusion protein in host cells was confirmed by the RT-PCR method. Six pathogen-free female mice were injected intramuscularly at a total concentration of 100 µg/mL three times at two-week intervals. The BCG and the control groups received BCG and PBS vaccines, respectively. One month after the final immunization, mice were killed and their splenocytes were cultured in RPMI medium supplemented with 1% antibiotics and 10% serum. Four cytokines including IL-4, IL-12, TGF-β, and IFN-γ were measured in the culture supernatant using the ELISA test.
    Results
    RT-PCR analysis showed that Ag85a-cfp10 recombinant vector is able to replicate in eukaryotic cells and produce mRNA. The vaccinated groups were compared to the control group, showing induction of high levels of cytokine production.
    Conclusions
    Some reports depicted that DNA vaccines are able to induce humoral and cellular immune responses both in animal models and humans. Therefore, in the current study, the immune response was induced in mice, which were inoculated with recombinant expression plasmid, pcDNA3.1 (+)-Ag85a-cfp10. We showed that this recombinant vector can stimulate mycobacterial specific modulating cytokines. Nonetheless, analysis appeared that this vaccine is unable to stimulate cell mediated immunity, however, still further studies are needed in future.
    Keywords: Mycobacterium tuberculosis, Plasmid, DNA, BCG Vaccine
  • Luna Fan , Xiang Ben Hou * Page 3
    Background
    Enterococcus faecalis is considered the primary pathogenic bacteria in failed root canal therapy due to its excellent biofilm formation ability. The second messenger cyclic dimeric (3’→5’) GMP (c-di-GMP) is involved in bacterial physiological processes, including biofilm formation. C-di-GMP is formed by diguanylate cyclases with the GGDEF domain.
    Objectives
    The current study aimed at investigating the function of DR75-RS11090 in E. faecalis.
    Methods
    In the current experimental study, gene encoding GGDEF domains in E. faecalis were analyzed through National Center for Biotechnology Information (NCBI) database. Enterococcus faecalis strains were cultured in brain-heart-infusion (BHI) broth at 37°C. Growth curves of E. faecalis were measured in an automatic microplate reader. Biofilms were fixed with 2% glutaraldehyde and scanned under the transmission electron microscopy. Acid and water-insoluble polysaccharide productions were also detected by the precise digital acidometer and anthrone method.
    Results
    It was found that DR75-RS11090 gene was predicted to encode GGDEF domain in E. faecalis. The current study observed promoting effects of DR75-RS11090 on E. faecalis biofilm formation, growth, acid production, and water insoluble polysaccharide production.
    Conclusions
    The current study findings improved the understanding of c-di-GMP in E. faecalis and presented a primary study on DR75-RS11090 promoting mechanism.
    Keywords: Biofilms, c-di-GMP, Enterococcus faecalis, DR75-RS11090, GGDEF
  • Mojtaba Moosavian , Ataallah Ghadiri , Sareh Amirzadeh , Mohammad Rashno , Maryam Afzali , Khadijeh Ahmadi * Page 4
    Background
    Chlamydia trachomatis, Ureaplasma urealyticum, and Mycoplasma hominis are common sexually transmitted microorganisms.
    Objectives
    The aim of the study was to determine the prevalence of these microorganisms in infertile couples and the effect of these infections on semen parameters.
    Methods
    In this case-control study, samples were collected from 50 infertile couples and 50 fertile women and men. Specimens were examined for the presence of C. trachomatis, M. hominis, and U. urealyticum by culture and PCR. Semen specimens were analyzed for apoptotic markers using the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay and Western blot.
    Results
    In this study, out of 50 semen specimens from infertile men, U. urealyticum and M. hominis were detected in 14 (28%) and 11 (22%) specimens by PCR, and five (10%) and one (2%) specimens by culture, respectively. C. trachomatis was found in five (10%) samples by PCR. In addition, out of 50 endocervical swabs from infertile women, C. trachomatis was found in seven (14%) specimens by PCR, U. urealyticum and M. hominis were detected in 25 (50%) and four (8%) swabs by PCR, and 13 (26%) and two (4%) by culture, respectively. The Western blot and TUNEL assay demonstrated a significant increase in caspase-3 activation and DNA fragmentation in the semen samples of the infected infertile men compared to uninfected men (6 vs. 1.5; P < 0.05).
    Conclusions
    The results demonstrated that C. trachomatis and genital Mycoplasma are widespread among infertile couples, and these infections may lead to decreased semen quality.
    Keywords: Chlamydia trachomatis, Mycoplasma hominis, Ureaplasma urealyticum, Infertility, Semen
  • Bita Bakhshi , Mina Boustanshenas*, Majid Akbari , Ali Majidpour Page 5
    Background
    Enterobacter cloacae bacteremia is reported as an important cause of morbidity and mortality. The members of E. cloacae complex are clinically involved in nosocomial infections.
    Objectives
    The purpose of this study was to investigate the prevalence of E. cloacae complex and its members in blood samples and conduct the hsp60 cluster analysis and genotyping of the isolates.
    Methods
    Eight isolates of E. cloacae complex were collected from blood cultures of hospitalized patients during the study period (December 2012 to November 2013). The hsp60 sequencing was done for the genetic classification. Pulsed-field gel electrophoresis (PFGE) was used for genotyping of the isolates.
    Results
    Fifty percent of the isolates belonged to two E. hormaechei subspecies. Three isolates (37.5%) clustered within genotype III while only one isolate fitted cluster XIII genotype (12.5%). Pulsed-field gel electrophoresis analysis revealed four different pulsotypes.
    Conclusions
    Different E. cloacae complex species and subspecies unequally contribute to the pathogenesis of blood infections and the subspecies of E. hormaechei were found to be most prevalent. Moreover, the common E. cloacae pulsotypes were observed to essentially produce identical hsp60 sequence types, indicating the probable clonality of isolates with identical pulsotypes.
    Keywords: Enterobacter cloacae, Heat-Shock Proteins, Pulsed-Field Gel Electrophoresis
  • Lima Asgharpour Sarouey , Khadijeh Khanaliha , Parvaneh Rahimi, Moghaddam , Samaneh Khorrami , Mohammad Saaid Dayer , Fatemeh Tabatabaie * Page 6
    Background
    The first line treatment against cutaneous leishmaniasis is meglumine antimoniate. This drug is expensive and has serious side effects, including development of drug resistance.
    Objectives
    In this research, because of paucity of information, the apoptotic and leishmanicidal effects of ketotifen and cromolyn sodium, as cell membrane stabilizer drugs, were investigated on standard strain of Leishmania major.
    Methods
    In this experimental study, L. major parasites were first cultured in RPM1 1640 media, supplemented with 10% fetal bovine serum (FBS) and antibiotics at 24 ± 1ºC. Drug concentrations of 5, 10, 15, and 20 µg/mL were then added to L. major culture at 24-, 48- and 72-hour intervals. The 3 - (4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide (MTT) tetrazolium assays were performed to determine parasite viability and drug toxicity. Leishmania major promastigotes were augmented to the in vitro cultured macrophages (J774 cells) and then incubated for 72 hours. Half maximal inhibitory concentration (IC50) were ascertained by counting the parasites. The inhibitory effect of the drugs were compared with that of glucantime. Flow cytometry was performed in the next step, to evaluate apoptosis. Each test was repeated three times.
    Results
    IC50 values of ketotifen and cromolyn sodium after 72 hours were calculated to be 2.04 and 17.67 µg/mL for promastigotes and 0.12 and 14.79 µg/mL for amastigotes, respectively. The results of MTT assays showed 20% and 35% promastigote viability after 72 hours of exposure to ketotifen and cromolyn sodium at 20 µg/mL concentration. Apoptosis in ketotifen and cromolyn sodium was quantified to be 11.52% and 9.96% in promastigotes and 99.5% and 98.6% in amastigote-infected macrophages, respectively. The results indicated that the drugs induce early and late apoptosis in parasites. All treatments produced results, which differed significantly from the control groups (P < 0.05).
    Conclusions
    Drugs used in this study, especially Ketotifen, showed lower toxicity yet similar anti-leishmanial effects on both forms, as cromolyn sodium did. It could be suggested that further investigations about the in vivo effects of these drugs, as candidates for cutaneous leishmaniasis treatment, are required.
    Keywords: Ketotifen, Cromolyn sodium, MTT, Apoptosis, IC50
  • Aneta Guzek , Zbigniew Rybicki , Dariusz Tomaszewski * Page 7
    Background
    The number of carbapenemase-producing Enterobacteriaceae cases is increasing, and the infections produced by such pathogens are a worldwide problem.
    Objectives
    The current study aimed at investigating the antibiotic resistance of carbapenemase-producing Enterobacteriaceae pathogens isolated from the biological materials obtained from patients hospitalized in our center, and analyzing the infections caused by such species.
    Methods
    The data were collected from January 2009 to December 2016 from urine, blood, wound exudate, the bronchial tree, abscess, and the abdominal cavity samples as well as cloacal swabs for fecal carriage. The samples were processed according to generally accepted microbiological procedures.
    Results
    The current study analyzed 122 Enterobacteriaceae isolates that can produce the carbapenemases: Klebsiella pneumoniae carbapenemase (KPC, 60%), New Delhi metallo-β-lactamase (NDM, 39.6%), and carbapenem-hydrolyzing oxacillinase (OXA-48, 0.8%). Of these 122 samples, 117 (96%) were K. pneumoniae, two (1.6%) K. oxytoca, two (1.6%) Escherichia coli, and one (0.8%) was Citrobacter freundii. In 2015 and 2016, a high isolation percentage of K. pneumoniae NDM pathogens was observed. All analyzed carbapenemase-producing Enterobacteriaceae were susceptible to colistin; 93% of the isolates were susceptible to tigecycline, and about 50% of the KPC pathogens were susceptible to aminoglycosides. The carrier state of carbapenemase-producing Enterobacteriaceae was confirmed in 35% of cases.
    Conclusions
    The current study results were comparable to the ones concerning the general microbiological situation in Europe. The relatively high incidence of NDM pathogens is alarming and may be resulted from the epidemiological situation in our region.
    Keywords: Drug Resistance, Bacterial, Carbapenem-Resistant Enterobacteriaceae, Klebsiella pneumonia, K. oxytoca, Escherichia coli, Citrobacter freundii