Jundishapur Journal of Microbiology
Year:2017 | Volume:10 | Issue:5|Papers Count:11

Background: Chronic hepatitis B (CHB), with accumulation of Hepatitis B surface Antigen (HBsAg) in hepatocytes, linked to the immune-mediated hepatic inflammation and induction of oxidative stress. 8-Hydroxyl-2’-deoxyguanosine (8-OHdG) is a useful biomarker for measuring the adverse effects of exogenous infectious agents in oxidative damage to DNA. Objectives: The current study aimed at investigating the possible oxidative adverse effects of HBsAg and systemic DNA damage in patients with CHB, and supporting the host-viral interaction in immune-mediated inflammatory. Methods: Thirty patients with CHB who had undergone liver biopsies for therapeutic purposes and 30 matched controls from a healthy population were randomly selected in the present study for assessment of 8-OHdGlevels in peripheral blood leukocytesDNA by 32P-postlabeling analysis. Expression of HBsAg in hepatocytes was evaluated immunohistochemically in liver biopsies of patients withCHB. The effect of 8-OHdG and 95% confidence interval (CI), adjusted by relevant confounders, were assessedonhepatitis B virus (HBV) infection. Results: Experimental investigation showed increased levels of DNA adduct 8-OHdG compared with healthy individuals (mean standard deviation, 1456 1275 vs. 402 271; P < 0. 001). The logistic regression with continuous and dichotomous models revealed the strong impact of 8-OHdG on CHB infection (OR = 1. 20; 95%CI: 1. 01-1. 44, P = 0. 043) and (OR = 7. 18; 95%CI: 1. 32-39. 02, P = 0. 022). HBV DNA and hepatic expression of HBsAg had a borderline association with DNA adduct 8-OHdG (r = 0. 35, P = 0. 054 and r = 0. 36, P = 0. 05). Conclusions: The current study showed that the adduct of 8-OHdG in peripheral blood cells DNA increased in patients with CHB compared with healthy carriers and the pathophysiologic role of HBsAg in oxidative stress in patients with CHB. Nonetheless, the lack of efficient DNA repair enzymes activity as well as a proper diet with antioxidant agents in CHB need to be clarified in future studies.

Background: Multi-drug resistant Escherichia coli and Klebsiella pneumoniae with various resistance determinants are a major concern in hospital and community acquired infections around the world. Objectives: To describe the presence of blaCTX-M, blaTEM, blaPER, blaVEB, and integrons class 1, 2, 3 and extended spectrum  lactamase (ESBL) phenotype in E. coli and K. pneumoniae isolates from clinical samples of inpatients and outpatients. Methods: One hundred and eighty six E. coli and fifty-eight K. pneumoniae were collected. Antimicrobial susceptibility test was performed by disk diffusion method. Extended-spectrum beta-lactamase phenotype were screened by phenotypic confirmatory test. PCR assay was performed for blaTEM, blaCTX-M, blaPER and blaVEB and class 1, 2, 3 integrase genes. Statistical analysis was performed by chi-squared test. Results: Extended-spectrum beta-lactamase phenotype was detected in 49 (26. 3%) E. coli and 19 (32. 8%) K. pneumoniae isolates. BlaVEB gene in 32 (17. 2%) E. coli and 5 (8. 6%) K. pneumoniae isolates. BlaPER gene in 4 (2. 1%) E. coli and 0 (0%) K. pneumoniae isolates. BlaCTX-M gene in 113 (60. 7%) E. coli and 34 (58. 6%) K. pneumoniae isolates. BlaTEM gene in 106 (57%) E. coli and 25 (43. 1%) K. pneumoniae isolates. One hundred and nine (58. 6%) of E. coli and 33 (56. 9%) of K. pneumoniae were carrying Class 1 integron and 18 (9. 7%) of E. coli and 3 (5. 2%) of K. pneumoniae were carrying Class 2 integron. Class 3 integron was not detected. Conclusions: High prevalence of ESBLs in E. coli and K. pneumoniae isolated from the community and hospital acquired infections could lead to the wide spread of multi-drug resistance clones that also contain new mechanism of resistance.

Background: The enterococci are responsible for infections including bacteremia and endocarditis which are usually resistant to multiple antibiotics. This nosocomial agent probably harbors putative virulence factors which increases their capability to colonize hospitalized patients. Objectives: This study was aimed in order to find the frequency of various virulence factors in enterococci and their relationship with multidrug resistance (MDR). Methods: The samples were collected from different hospital wards including; Intensive care unit (ICU), cardiac care unit (CCU), pediatrics department, internal wards, and transplantation. The isolates were detected by biochemical tests and in order to determine the antibiotic susceptibility pattern, disk diffusion agar (kirby-bauer) was accomplished. Then, MICs (Minimum inhibitory concentrations) of vancomycin were determined by E-test strips. For molecular examinations and detection of drug resistance genes, the simple polymerase chain reaction was used. The multiplex PCR was used in order to detect virulence factors. Results: Total of 85 isolates were obtained from one university teaching hospital in southeast of Iran. Approximately 95% of isolated which were from urine specimens and 34% of isolates were collected from pediatrics units at hospital. Tetracycline resistance (48%) has been observed with a high frequency and related to the tetM gene. Furthermore, eighteen isolates were recognized as MDR strains that carried vanA, aac (6)-Ie-aph (2)-Ia, ermB, and tetM genes. Among virulence factor genes, asa1 (69%) and gelE (55%) are more frequently observed in both species. In general, we found Enterococcus faecalis strains more prevalent. Also, E. faecium was related to antibiotic resistance genes in nosocomial infection. Conclusions: The data was indicated a high prevalence of multiple antibiotics resistance genes with virulence determinants in enterococci and also considered resistant isolate in pediatrics unit. The current results can be recommended in order to change new strategies for antibiotic therapy, because this serious pathogen is important for treatment and eradication in hospitals. Furthermore, the biofilm formation was regulated and constructed by virulence determinants that could be a candidate for enterococcal treatment.

Background: Helicobacter pylori is colonized in stomach and has a significant etiological role in different kinds of digestive diseases. Helicobacter pylori has the ability to devastate duodenal mucus causing peptic ulcer. Breakage of stomach lining is also seen more often among people who accustomed to consume tobacco, spicy (or sour) foods, alcohol, coffee, and tranquilizers as well as those who are exposed to heavy meals and stressful-life events (stress ulcer). Also, it seems dup A and ice A genes are involved in H. pylori etiology. Objectives: This study aimed to determine the relation of jhp0917 and jhp0918 genes, ABO blood type, and some environmental factors with peptic ulcer. Methods: In our study, 500 gastric mucosal biopsy samples from digestive tract were examined by rapid urease test (RUT) and 16s rDNA PCR test for H. pylori infection followed by histopathological examinations. The dup A and ice A genes were also evaluated by PCR. Results: In H. pylori colonized peptic ulcers, dup A gene showed no significant relation with peptic ulcer. On the other hand, iceA 1 (+)/ iceA 2 (-) genotype of H. pylori showed a strong association with peptic ulcer (P < 0. 05). Conclusions: ABO blood group showed no association with H. pylori infection. Peptic ulcer had a significant relationship with consumption of tobacco (P < 0. 05), consumption of tranquilizers (P < 0. 05), and meteorism (P < 0. 05).

Background: Replication of influenza virus to high titer is a prerequisite for successful cell-based vaccine production. Entry of virus into the cell depends on the cleavage of the hemagglutinin precursor (HA0) protein mediated by trypsin. Objectives: The aim of the present study was to apply a technique to establish MDCK/FX manipulated cell, which may provide a new platform for developing influenza vaccine based on the cell culture approaches. Methods: Chicken embryo FX expressed into the pCDNA3. 1 vector was transfected into the MDCK cell line. The longevity of the generated cell and the viable cell density were evaluated for 17 passages prior to virus inoculation. Then, the ability of MDCK/FX cell for efficient replication of H9N2 influenza virus was evaluated by viral titration and quantitative RT-PCR. Results: RT-PCR data revealed that FX was stably expressed in the cell after the subsequent passages without any change in the rate of culture’ s confluency. Growth kinetic of H9N2 virus analysis demonstrated that MDCK/FX cell supported high-titer growth of the virus in which the viral titer is comparable to the virus grown in MDCK cells supplemented with TPCK-trypsin. Quantification of influenza infectious particles in the cell culture revealed the equivalents viral RNA copies and viral titers. Conclusions: The results indicated a potential application for the MDCK/FX in influenza virus replication procedure and related studies.

Background: Repeated blood transfusions in Thalassemic patients predispose them to blood-borne infections including Hepatitis B, Hepatitis C, and human immunodeficiency virus. These infections cause cirrhosis, portal hypertension, and acquired immunodeficiency syndrome. Objectives: The current study aimed at determining the prevalence of these infections in Thalassemic patients of Kermanshah province, Iran. Methods: Thalassemic patients registered at Mohammad Kermanshahi university hospital were included. Demographic data, history of blood transfusions, Hepatitis B surface antigen (HBsAg), Hepatitis B core antibody (HBC Ab), Hepatitis B surface antibody (HBs Ab), Hepatitis C antibody, and Human immunodeficiency virus (HIV) antibody were extracted. Serologic tests were done using the third-generation enzyme linked immunosorbent assay (ELISA) and positive Hepatitis C virus (HCV) Ab and HIV Ab results was confirmed byWestern Blotting. Results: A total number of 232 patients were enrolled (111 females and 121 males), among whom HBsAg and HIV Ab were both negative. Positive HBS Ab was reported in 222 subjects (95. 7%) and 19 cases (8. 2%) had positive HBC Ab. Immunity to hepatitis B was the result of vaccination in 87. 5% of cases. Hepatitis C antibody was positive in 14 cases (6%). Finally, a significant relationship was found between HCV infection and blood transfusion done before 1996. Conclusions: High rate of hepatitis C was found to be due to the lack of screening for HCV Ab among blood donors before 1996. The negative HBS Ag can be justified by regular hepatitis B vaccination program in patients with thalassemia. The lack of HIV infection was concluded to be attributed to the low prevalence of this virus in the general population and blood donors as well as proper screening methods.

Background: Extended spectrum beta-lactamase (ESBL) producing organisms causing urinary tract infections are increasing in incidence and becoming a serious health problem due to their resistance to large number of antibiotics. Objectives: To investigate the ESBL prevalence of Escherichia coli and Klebsiella spp. which are isolated from urine samples for both in and outpatients with their resistance profiles. Methods: From 2004 to 2012, a total of 13975 isolates (12897 E. coli, 1078 Klebsiella spp. ) were included in this study. The antibiotic susceptibility was tested using Kirby– Bauer disk diffusion method and Vitek2 System (bioMerieux, France) according to CLSI. Results: Our data showed a significant increasing in ESBL prevalence from 12. 5% to 44. 7% (P < 0. 001) for inpatients; from 9. 6% to 22. 8% (P< 0. 001) for outpatients in E. coliandfrom 25% to 60. 5% (P< 0. 003) for inpatients; from 12% to 25% (P< 0. 095) for outpatients in Klebsiella spp. For E. coli, the increase was significantly high in both of males and females (P < 0. 001). However, for Klebsiella spp. it was significantly high in male patients (P < 0. 001). The resistance rates of antibiotics for the ESBL producing E. coli, and Klebsiella spp. showed a significant increase. These rates were higher than 70% for fluoroquinolones, amoxicillin-clavulanic acid and trimethoprim-sulfamethoxazole. Even carbepenem resistance reached to 7% in the outpatients and 15% in inpatients for ESBL producing Klebsiella spp. Conclusions: Our study demonstrated a significant increase in the prevalence of ESBL producing E. coli and Klebsiella spp. and a remarkable carbapenem resistance trend in the ESBL producing Klebsiella spp. isolated from urine samples.

Background: Acinetobacter baumannii is currently considered one of the greatest causes of nosocomial infection. The rapid emergence and spread of resistance to most conventional antibiotics highlight the need to identify novel antimicrobial agents. Antimicrobial peptides (AMPs) are introduced as potential therapeutic alternatives. Human anionic antimicrobial peptide, dermcidin-1L (DCD-1L), has shown antimicrobial activity against a wide range of nosocomial pathogens; however, it is still unknown whether it exhibits such properties against A. baumannii. Objectives: For the first time, the present study was conducted to examine the antimicrobial activity of DCD-1L against biofilmforming extensively-drug-resistant (XDR) and pandrug-resistant (PDR) isolates of A. baumannii, belonging to different clonal lineages. Methods: Dermcidin-1L was examined in terms of antimicrobial properties against 1 biofilm-forming representative XDR isolate from each clonal lineage and 1 PDR isolate via minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) analyses and time-kill assay. Dermcidin-1L resistance mutation frequency in A. baumannii was also determined. Results: Minimuminhibitory concentration andMBCof DCD-1L against all 8 representative XDR and standard (ATCC 19606) isolates were 16 and 32  g/mL, respectively, while the corresponding value for 1 PDR isolate was 8  g/mL. The time-kill assay results revealed that the bactericidal effects were more rapid against PDR than XDR strains. In addition, the tested AMPs showed a low tendency to develop resistance. Conclusions: The present results showed that DCD-1L exhibits interesting antibacterial properties against PDR A. baumannii strains, making it a promising candidate for the development of new antiinfective therapies.

Background: Staphylococcus aureus is one of the major causes of community-and hospital-acquired infections, with methicillinresistant strains showing the highest rates of morbidity and mortality. In our previous experiment, isolates, which were also used in the present study, were assessed using multilocus sequence typing (MLST). The sequence types (STs) were determined and documented in the corresponding database. Objectives: In the current study, the isolates were subjected to genotyping with coagulase, SCCmec, and agr typing methods. Methods: A total of 54 isolates were evaluated by polymerase chain reaction (PCR) assay for mecA gene, Sccmec typing, and finally PCR-restriction fragment length polymorphism (RFLP) for coagulase (coa) gene using Alul enzyme. MLST of the isolates showed that the majority of methicillin-resistant S. aureus (MRSA) isolates belonged to ST239. Results: Phenotypic and genotypic tests revealed that 21% of the isolates were MRSA. PCR-RFLP test for coa gene showed similar patterns of MRSA isolates. The majority of the isolates were community-acquired and belonged to the Sccmec type IV, whereas the remaining were hospital-acquired and classified as type I (22. 2%) and type III (2. 2%). Conclusions: Most of the isolates belonged to agr type I, followed by type II and type III. Agar dilution method showed higher sensitivity and specificity, compared to the disk diffusion method. The majority of the isolates were community-acquired and belonged to Sccmec type IV and agr type I, whereas the remaining were hospital-acquired and classified as types I (22. 2%), type III (2. 2%), and agr type I.

Background: Acinetobacter baumannii as the most important nosocomial pathogen can cause various types of clinical infections. Multidrug resistance in A. baumannii strains has significantly limited the choice of available therapeutic options for treatment of patients and is a serious threat to hospitalized patients, especially those in intensive care units. Objectives: The present study was performed to investigate the frequency of classes 1, 2, and 3 integrons in A. baumannii strains isolated from selected hospital ICUs. Methods: A total of 105 A. baumannii isolates were collected between October 2015 and April 2016 from 4 medical centers located in different regions of Tehran, Iran. The resistance rate to different classes of antimicrobial agents was assessed using Epsilometer test. Conventional PCR was performed for the detection of blaOXA-51-like gene and integrase gene. Restriction Fragment Length Polymorphism technique using RsaI and HinfI restriction enzymes was used to detect integron classes. Results: All the isolates were observed to be susceptible to colistin and polymixin B and inhibited at similar minimum inhibitory concentration (MIC) 50 (MIC50) andMIC90 1 g/mL. All the tested A. baumannii isolates were multidrug resistant. The rate of extensive drug-resistance among these clinical isolates was 71. 4%. The highest and the lowest levels of resistance were observed to be related to ciprofloxacin (96. 2%) and netilmicin (40%), respectively. Resistance rates to other antibiotics tested were between 43. 8% and 80%. The prevalence of classes 1 and 2 integrons was found to be 66. 7% and 20%, respectively. Class 3 integron was reported, for the first time, in three A. baumannii strains (2. 9%) isolates from Tehran, the capital of Iran. Conclusions: The results revealed that the dissemination of multi-drug resistance among A. baumannii isolates may be associated with the presence of integrons. The findings highlighted the need for continuous surveillance to monitor integrons among A. baumannii strains.

Background: Helicobacter pylori is a common cause of chronic infections worldwide. Helicobacter pylori urease is a multimeric enzyme with a molecular weight of 530 kDa, which is collected from two separate subunits of UreA (26. 5 kDa) and UreB (61. 7 kDa). Objectives: This study aimed to evaluate the antigenic properties of UreB recombinant protein as a vaccine candidate for the infected sera of humans and mice. Methods: In this study, the highly antigenic region of UreB gene (609 bp) was detected, using immunological bioinformatics for epitope mapping, amplified by polymerase chain reaction (PCR). Afterwards, the antigen was cloned, using a pBSK cloning vector and was inserted into a pET-32a expression vector; the target protein was then expressed and purified. Eventually, antigenicity was examined by immunoblotting on the sera of humans infected with H. pylori UreB recombinant protein. Results: The sequencing results of PCR were indicative of UreB gene cloning into the recombinant plasmid. Production of the protein was induced by isopropyl -D thiogalactopyranoside (IPTG), and the expressed protein was purified via dialysis, using the Ni-NTA kit. In addition, the recombinant protein with a molecular weight of 42 kDa was recognized by antibodies inWestern blotting. Conclusions: The evaluation of antibodies was indicative of high antigenic properties for the immunogenic fragment, predicted by immunological bioinformatics. Therefore, UreB recombinant protein might be a proper antigen for the development of vaccines against H. pylori and other diagnostic kits.