Iranian Journal of Microbiology
Volume:7 Issue: 2, Apr 2015

The prevalence of community acquired methicillin resistant Staphylococcus aureus (CA-MR- SA) is increasing around the world. It involves healthy people and causes a variety of diseases. This cross sectional study was conducted from September 2010 - June 2011 on children less than 14 years of Ahvaz, southwest Iran. The participants were selected with two staged cluster sampling. A sterile cotton nasal swab was used to collect the samples from the 864 participants. MRSA isolates were identifed by catalase and coagulase tests and 1 μg oxacillin disk method. Polymerase chain reaction (PCR) was performed on all the MRSA colonies to detect the mecA gene. Data was put in SPSS 16 software and descriptive statistics and chi-square test were used for analysis. Out of 864 children, 471(54.51%) were male and 393 (45.49%) were female. 235 children (27.1%) had Staphylo- coccus aureus and 11 (1.3%) of all children diagnosed with MRSA. PCR showed that 7 colonies (0.8%) had the mecA gene. The results of this study indicate that MRSA exists in healthy children of Ahvaz. Although the prevalence of CA-MRSA is lower than many other regions, it still needs close attention to prevent its transmission. Further studies are needed to identify the risk factors of CA-MRSA.

ackground and The main cause of serious nosocomial infections is a Gram-negative pathogen known as Pseudomonas aeruginosa (P. aeruginosa). Carbapenems are widely used as an appropriate treatment for these infections, however resistance to these agents has been observed and is increasing. Metallo beta-lactamase (MBLs) enzyme is one of the main causes of resistance to carbapenem. In the current study the frequency and production of VIM1 and VIM2 by imipenem-resistant P. aeruginosa isolates of patients hospitalized in Imam Reza hospital were evaluated. In this study, 131 clinical samples were collected from patients hospitalized in Imam Reza hospital in Mashhad during a 15-month period from May 2011 to November 2012. After verification of P. aeruginosa isolates, antibiotic resistance patterns of isolates were determined for 14 antibiotics by Kirby-Bauer standard disk diffusion according to the CLSI guidelines. Combined-disk test was used for phenotypic determination of MBLs-producing isolates and after DNA extraction, genotypic determination of VIM1 and VIM2 metallo beta-lactamase genes was carried out using Multiplex- PCR. Of 63 imipenem-resistant isolates (48.5%), 56 (88.8%) were MBL-producing in phenotypic assessments. Also amongst imipenem-resistant isolates, the frequency of VIM1 and VIM2 genes were 58.7 and 3.17%, respectively. The results of the current study along with the results of the other conducted studies in Iran in recent years demonstrate that the average resistance to imipenem in P. aeruginosa isolates was 51.3% which has increased in comparison with the results in 2006 (32.9%). It was also determined that the frequency of VIM1 gene was more than VIM2 gene. In phenotypic assessment by using CD method, 49.6% of isolates were determined as MBLs-producing. The sensitivity and specificity of this method were verified in comparison with the results of PCR test.

Haemorrhagic septicaemia (HS), caused by Pasteurella multocida, is the most important bacterial disease of cattle and buffaloes in India. Oil adjuvant vaccine (OAV) is the most potent vaccine available for the control of HS. The study aims to evaluate the effect of alum co-adjuvantation of OAV on emulsion stability and immune response. Two different oil adjuvant vaccines viz., standard oil adjuvant vaccine (OAV) and alum precipitated oil adjuvant vaccine (A–OAV) were prepared with Pasteurella multocida antigen. Emulsion stability was tested by centrifugation, storage at 37 oC for 3 months and microscopy. Immune responses were evaluated by ELISA antibody titer, CD4, CD8 T cell populations and survival post challenge by P. multocida in mice. The separation of aqueous and oil phase of emulsion by centrifugation and storage test were 0 and 6.76% in A-OAV as compared to 11.00 and 26.39% in OAV, respectively. The mean droplet size was significantly smaller (p<0.01) in A–OAV as compared to OAV. The A–OAV recorded higher ELISA antibody titer (p<0.05) up to 21st days post vaccination, and higher CD4 (p>0.05) and CD8 T cell (p<0.05) populations compared to OAV. The A–OAV group conferred 100% protection after challenge with both 100 LD50 and 1000 LD50 as compared to 100 and 60% respective protection by OAV group. The results indicates that A–OAV had better emulsion stability, produces higher level of CD4, CD8 T cells and antibody titer with better protection compared to oil adjuvant vaccine.

The rapid emergence and dissemination of carbapenemase-producing Klebsiella pneumoniae strains and other members of the Enterobacteriaceae poses a considerable threat to the care of hospitalized patients and to public health. The aim of this study was to determine the frequency of metallo-β-lactamases (MBL) and VIM-1 gene in multidrug-resistant strains of K. pneumoniae. 50 isolates of non – duplicated K. pneumoniae cultured from patients at intensive care units were tested for their susceptibilities to 13 different antibiotics using microbroth dilution assay. Isolates showing resistance to at least one of the carbapenems were checked for production of metallo-β-lactamase (MBLs) using imipenem–EDTA synergy tests. PCR was used to detect the gene encoding VIM-1 metallo-β-lactamase (MBL). Of 50 clinical isolates, 26 (52%) were resistant to imipenem in disk diffusion method. Using imipenem–EDTA synergy tests, production of MBL was detected in 15 (30%) isolates. PCR assay showed that 15 isolates were positive for VIM and these included 10 and 5 isolates showing positive and negative results in phenotypic method of MBL detection test respectively. Amikacin was found as the most effective antibiotic against the MBL producers in this study. The emergence of bla(VIM-1) producing K. pneumoniae in North of Iran is concerning. Microorganisms producing bla(VIM-1) constitute the prevalent multidrug-resistant population of K. pneumoniae in that region.

Selenium is essential for biological systems at low concentrations and toxic at higher levels. Heavy metals and metalloids such as selenium are major contaminants in 40% of hazardous waste sites. Thus, bioremediation has been considered as an effective means of cleaning up of selenium-contaminated sites. In this study, 30 strains were isolated from wastewater samples collected from selenium- contaminated sites in Qom, Iran using the enrichment culture technique. One bacterial strain designated QW4, identified as Proteus hauseri by morphological, biochemical and 16S rRNA gene sequencing was studied for its ability to tolerate different concentrations of sodium selenate (100-800 mM). Also, the disk diffusion method was performed to determine resistance to some antibiotics Strain QW4 showed maximum minimum inhibitory concentration (MIC) to selenate (760 mM). The maximum selenate removal was exhibited at 35 ºC, while the removal activity reduced by 30.7% and 37% at 25 ºC and 40 ºC, respectively. The optimum pH and shaking incubator for removal activity was shown to be 7.0 and 150 rpm, with 60.2% and 60.3%, respectively. This bacterial strain was resistant to some antibiotics. The concentration of toxic sodium selenate (1000 µg/ml) in the supernatant of the bacterial culture medium decreased by 100% after 2 days and the color of the medium changed to red due to the formation of less toxic elemental selenium. Also, our results imply that heavy metal pollution may contribute to increased antibiotic resistance through indirect selection.

Hepatitis E virus (HEV) is the most common cause of acute viral hepatitis in the world. It is usually a self-limited disease but may leads to the deaths of about 20% of pregnant women in developing countries. This study was conducted to determine the prevalence of HEV infection among HIV individuals. This is a cross-sectional survey of HIV positive individuals in voluntary counselling and testing center of Shiraz in 2013. Using the systematic random sampling method, 158 patients enrolled for the research. They were asked about their age, gender, area of residence, marital status, number of children, education level, occupation, history of imprisonment, mode of HIV transmission, and viral hepatitis co-infection. Three ml venous blood sample was drawn from each subject and transferred to the laboratory of voluntary counselling and testing center. The overall seroprevalence of hepatitis E was 26 (16.4%), where it increased significantly with age ranging from zero in subjects less than 30 years of age to 47.4% in those aged 50 years or older. Co-infection of HIV positive individuals with HEV is an issue that should be of concern to health care pro- viders.

Hepatitis C Virus genotyping appears to be vital for predicting the response to antiviral therapy. The present study aimed to analyze the HCV genotypes in relation to persistence or clearance of the virus in residents of Hamadan Province, West-Iran. A total of 1159 recorded questionnaires of HCV infected people were evaluated in this prospective study. Several parameters including HCV genotypes, anti-HCV antibodies, viral load, drug treatment, response to therapy and amount of ALT and AST were analyzed. HCV genotyping in 637 samples revealed a predominance of type 1a (52.1%) followed by 3a (42.4%), type 1b (2.7%) and type 2 (0.2%) respectively. Mixed genotypes (3a-1a) were detected in 0.9%, and 1.7% had untypable genotype. High frequency of genotypes 1a and 3a were observed in drug-resistant (group-a) and drug-sensitive (group-b) patients respectively (P<0.0001). Additionally, duration of drug treatment was significantly higher in group-a than group-b (P<0.0001). During follow-up period, 92 cases showed spontaneous clearance of HCV infection and more importantly 86 of 92 cases were positive for anti-HCV antibodies compared with 59 of 455 antibody positive cases with treatment-induced clearance of HCV infection (P<0.0001). HCV genotyping and also antibody screening could be useful for proper therapeutic intervention in HCV infected subjects.

Frosted branch angiitis(FBA) is a panuveitis with sheating of all retinal vesssels. Herein we report an immunocompetent person who presented with fever, headache, atypical rash, and hazy vision. Ophthalmoscopy of both eyes revealed perivascular sheathing with frosted branch angiitis pattern in veins, patchy retinal hemorrhages. Aqueous PCR analysis turned positive for VZV. This case illustrates that VZV should be considered in the differential diagnosis of retinal perivasculitis. Since a rapid and accurate diagnosis is crucial for prompt administration of antiviral therapy, PCR-based analysis of aqueous humor is a valuable tool for detecting viruses.