دو ماهنامه میکروب شناسی پزشکی ایران
سال دوازدهم شماره 5 (آذر و دی 1397)

Acinetobacter baumannii is a major cause of nosocomial infections and is resistant to many antibiotics. Over expression of AdeABC and AdeIJK efflux pumps in Acinetobacter causes resistance to aminoglycosides and decreases the sensitivity of fluoroquinolones. The aim of this study was to investigate the phenotypic activity of the Acinetobacter baumanni isolates associated with presence of adeA, adeB, and adeI genes. The study was performed on 55 strains of A. baumannii isolated collected from specimens of patients hospitalized in Milad Hospital , Tehran. The isolates were diagnosed using biochemical tests and antibiotic susceptibility testing was done by disk diffusion method based on CLSI guidelines. Cartwheel method was used to study phenotypic activity of efflux pump. Multiplex PCR was used to determine the presence of genes. The prevalence of multiple drug resistant isolates was 98%. In terms of efflux pump activity 3.63% isolates were strong, 67.27% moderate and 29.09% were non-active. The frequency of adeA, adeB, adeI genes was 87.2%, 85.4% and 94.5%, respectively. There was significant association between adeA and adeB genes among isolates with actively and non-actively efflux pump. Determination of actively phenotype of efflux pump can determine the multiple drug resistance among A. baumannii isolates. The results confirms the role of main genes encoding AdeABC operon,adeA and adeB in activity of A. baumannii efflux pump.

Uropathogenic Escherichia coli (UPEC) are a causative agent in most of the urinary tract infections (UTIs) contain pathogenic island (PAI) which expresses a multitude of virulence factors. There is not much information about the type and distribution of these islands in the phylogenic groups of E. coli causing UTIs in different regions of Iran. In this study, the distribution of the pathogenicity island (PAI) markers infections was investigated among phylogenic groups of E. coli isolates collected from patients with UTIs using Multiplex-PCR method. In this descriptive study, 100 isolates of E. coli collected from previous studies were conducted to determine the frequency of pathogenic islands and their distribution among phylogenic groups. In this method, genomic DNA of isolates was extracted by boiling method. Determination of the frequency of pathogenic islands was performed using Multiplex-PCR method. The results were analyzed using Fisher’s exact test. The prevalence of PAI IV536, PAI ICFT073, PAI IICFT073, PAI II536 and PAI IIJ96 was 84%, 44%, 30%, 16% and 9%, respectively. The PAI I536 and PAI IJ96 pathogens were not observed in any of the isolates. The highest distribution of PAI IV536 island between phylogenetic groups B2 and D was 88% (46 out of 52) and 100% (19 out of 19), respectively. In this study, isolates belonging to groups B2 and D were found to be the most pathogenic islands; therefore, they could play a more effective role in urinary tract infection than other phylogenic groups.

Urinary tract infections are among the most common infectious diseases. The bacterium of Escherichia coli, which produces verotoxin venom, is one of the most common causes of urinary tract infections. The aim of this study was to identify the molecular and serotyping of the isolates of E. coli producing verotoxin from the urinary tract infection in patients referred to the health centers in Khoy. 200 urine samples of people suspected to urinary tract infection were identified by using standard culture and biochemical methods of E. coli. The bacterium was isolated in term of the susceptibility pattern to antibiotics and was studied using disc diffusion method. To do Serotyping, strains with polyvalent antisera were tested. DNA was isolated from bacteria after extraction. The Verotoxin producing isolates were identified by Multiplex PCR. 78 urine samples were identified as E. coli. E. coli isolates had the most antibiotic resistance to ampicillin and had the highest susceptibility to Norfloxacin. In serotyping, Group 3 had the most common strains of E. coli. Among the samples that were studied using Multiplex PCR and specific primers, stx1 genes were observed in 3 isolated isolates and stx2 genes were observed in 16 isolated isolates and both stx1 and stx2 were seen in 9 isolates. Serotypes of O25, O78, O103, O118, O124, O145, O157 and O164 were the most frequent infection-specific serotypes. The frequency of E. coli strains with stx2 gene producing verotoxin was more than stx1. High resistance to ampicilin is probably due to the excessive consumption of these antibiotics. Norfloxacin can be an appropriate choice for the treatment.

Pharmaceutical residuals like antibiotics in livestock products and their consumption by humans from food chain can lead to the spread of bacteria resistant to antibiotics. The aim of the current study was to investigate antibiotic resistance and determine the prevalence rate of genes encoding extended spectrum beta-lactamase (ESBLs) in Acinetobacter strains isolated from raw foodstuffs. In this study, 300 samples from protein foodstuffs (mutton, beef, chicken, hamburger, hot dog, sausages) and dairy foodstuffs (raw milk and cheese) were prepared and investigated in terms of contamination with Acinetobacter baumannii from July 2015 to November 2016. The isolated bacteria were identified by biochemical tests to species level and confirmed by the PCR technique via blaOXA-51 gene. Antibiotic resistance of the isolates was studied using the diffusion disc method. Also, the presence of ESBLs enzymes in the isolates wa s done phenotypically and genetically through PCR and combined disk tests. The results showed that 43 strains of A. baumannii were isolated from the protein and dairy foodstuffs, 93% from protein foodstuffs and 7% from dairy foodstuffs. Also, 30% of the isolates had multidrug- resistance (MDR). Further, the findings of PCR illustrated that the prevalence of genes encoding ESBLs in the isolates were: TEM 21%, PER 23.5%, VEB 18.5 % and SHV35%. Foodstuffs can act as a food source for A. baumannii that can lead to transferring and spreading genes encoding antibiotic resistance to humans.

Food contamination by fungi threatens human health. Active packaging containing antifungal compounds is a novel method to increase the safety and preservation of food. The aim of this study was to produce and investigate the antifungal properties of poly-lactic acid active film containing iron nanoparticles in grape juice packaging. Poly-lactic acid nanocomposite films were prepared by casting method through adding different amounts of nanoparticles (0, 2 and 4%) to 4% (w/w) solution of poly-lactic acid in chloroform and antifungal effect of films were investigated in in vitro and grape juice packaging. For this purpose, circular disks (6 mm) of film were prepared and placed on Potato Dextrose Agar media culture inoculated whit Aspergillus niger, Penicillium notatum, Botrytis cinerea. The diameter of the zone of inhibition was reported based on millimeters after 5 days of incubation of the plates at 27 ° C. In order to investigate the antifungal effect of nanocomposite in packaging of grape juice, 5×104 cfu/ml of these molds were inoculated to pasteurized grape juice and then packed with termal sewing and after a 15-days period, the molds population was counted. The distribution of nanoparticles in the polymer, was uniform at concentration of 2% and formed agglomerate at concentration of 4%. The results of the disc diffusion test showed that adding of nanoparticles to the film caused antifungal effect against the tested fungi and this property increased with increasing percentage of nanoparticles. Also, the results of the study on the antifungal effect in grape juice packaging in the 15-days period showed that the population of fungi had an inverse relationship with concentrations of iron nanoparticles in grape juice samples. A. niger showed the most and B. sinera showed the least resistance to this nanoparticle. Significant compatibility between iron nanoparticles and poly lactic acid provides the possibility of producing poly-lactic acid nanocomposite as an alternative for synthetic polymers from petroleum derivatives. Iron nanoparticles produce anti-fungal effects through the leakage of lactase dehydrogenase from the cell wall, impairment in mitochondrial function, chromosomes compression, and production of free radicals of oxygen. Due to the antifungal effect of iron nanoparticles, its application in poly-lactic acid film decreases fungal growth and, as a result, increases the shelf-life of foods.

Cervical cancer is the second most common cancer in women worldwide. The presence of HPV has been implicated in more than 99% of cervical cancer worldwide. Human papillomavirus is a heterogeneous virus, categorized to two groups of high-risk and low-risk genotyped according to the level of infection that leads to cervical cancer. HPV screening is recommended for the further evaluation of abnormal pap test or during follow-up after treating precancerous lesions. Genotyping of different high-risk HPV (hrHPV) types obtained from smear tests has not yet gained widespread acceptance in clinical practice. Genotyping of hrHPV could be helpful for the risk stratification of HPV-positive. In this study 143 women residual samples were available for HPV assays in Masoud laboratory in Tehran. After extracting DNA by kit, for genotyping detection of human papillomavirus PCR amplification, Reverse dot blot hybridization methods was used. Among these samples, 34.2% were HPV positive. In this research, the most common genotype was HPV-18 from high risk HPV genotype and HPV-6 was the most common from low risk genotype of HPV. The most Age category that has been detected positive HPV from category 26-35 years. The variety of HPV genotype detection in cervical cancer screening increases the importance of epidemiological study controversially in world. Therefore for characterizing genotype of HPV, Reverse dot blot hybridization can be of great help in this regard.

Chickenpox is a highly contagious disease caused by infection with Varicella Zoster Virus (VZV). Although it is usually a self-limited disease, but severe complications may occasionally occur. The aim of this study was to investigate the seroprevalence of VZV antibody among students of Babol University of Medical Sciences especially female students in reproductive age. 270 students were enrolled to our study. After signing a written informed consent, demographic data and 5 ml blood sample were collected from each participant. Following serum isolation, each serum sample was assessed by ELISA technique for VZV IgG.
Results and Of two hundred and seventy students, 197 were female and 73 were male. Out of female students, 145 students (73.6%) were single and in reproductive age. 17.3% of female students and 8.2% of male students were seronegative and susceptible to VZV infection. Besides, 7.9% of unmarried male students and 20.7% of unmarried female students were susceptible to VZV infection. The highest susceptibility to VZV was seen in 18-21 years age group. Therefore, more than 20% of unmarried female students were susceptible to VZV, which can be important regarding infection during pregnancy and subsequent severe complications. Consequently, vaccination for VZV in susceptible students especially unmarried female students is recommended.

Extended-spectrum beta-lactamase of SHV, PER and VEB types are considered as important and widely increasing resistance mechanisms to beta-lactamases in gram- negative pathogens. Also K. pneumonia species are able to produce extended-spectrum beta- lactamase (ESBLs). The aim of this study was to detect the prevalence of SHV, PER and VEB genes in ESBLs producing Klebsiella pneumoniae isolates which were collected from patients of different regions of Tehran city between January 2017 to January 2018 using PCR method. In this analytical- descriptive study, antibacterial susceptibility of 176 K. pneumonia isolates were defined to Cefepime, Ampicillin, Gentamicin, Cefalotine, Ceftazidime, Ciprofloxacin, Imipenem, Cefotaxime and Nitrofurantoin using disk diffusion method. In addition, confirmatory test for detecting ESBLs phenotypes was performed using Cefotaxime-Clavulanic acid combination disk. The presence of SHV, PER and VEB genes were assessed using PCR.
Results and Confirmatory phenotypic test showed that 56.81% of the isolates were ESBL positive. The prevalence of SHV, PER and VEB genes in K. pneumonia isolates was 34%, 13% and 17% respectively. In this study, the most resistance rate was observed to ampicillin (89%) and the lowest resistance rate was observed to imipenem (7%). High frequency of SHV, PER and VEB genes in ESBL producing isolates, indicates that these enzymes play important roles in resistance to beta lactam containing anti biotics. Therefore, proper infection control tools and appropriate therapeutic approaches in different parts of the hospitals are necessary to prevent their spread.