دو ماهنامه میکروب شناسی پزشکی ایران
سال یازدهم شماره 3 (امرداد و شهریور 1396)

Stem cells are primary, unspecialized and mother of all cells that can differentiate into specialized cells and can produce more stem cells. These cells are classified into totipotent, pluripotent and multipotent. Stem cells have the remarkable potential to develop into many different cell types in the body and can replace damaged tissues and repaired them in the human body. Therefore, the use of stem cells shows the extraordinary ability to treat a wide range of disabling diseases. Stem cell therapy is the use of stem cells to treat or prevent a disease and injury. They stimulate the body to repair itself. Stem cells can be used for treating and preventing many diseases such as diabets, spinal cord injuries, cardiac infarction, arthritis, Alzheimer, Parkinson and wound healing. Researchers have recently used these cells to treat parasitic diseases in some cases. The findings show that the use of these cells in the treatment of various parasitic diseases such as malaria, trypanosomyosis, schistosomiasis, leishmaniasis and echinococcosis, have inhibitory effects which improves the function of the tissue and involved organs. This study summarizes the new advances in the stem cell therapy against parasitic infections.

plasmid genes are responsible for resistance to quinolones and fluoroquinolones, so the present study aims to identify the presence of qnr and aac genes in clinical isolates of P. aeruginosa.
In 2016, 60 strains of P. aeruginosa were isolated from clinical specimens of patients in Kerman hospitals. Antibiotic resistance patterns were evaluated using Kirby-Bauer and microdilution methodsagainst 10 antibiotics according to CLSI criteria Specific primers and polymerase chain reaction were used to detect and amplify qnr and aac(6)-Ib-cr genes.
Maximum antibiotic resistance was observed against cefexim (80%) and calidixic acid (75%) and minimum resistance against imipenem (25%) and ciprofloxacin (35%). The incidence rate of quinolone resistance genes were as follows: qnr A (16.66%), qnrB (13.33%), qnrS (11/66%) and aac(6)-Ib-cr (8/33%).
In the present study, qnrA gene had the highest incidence rates among the studied genes. Because of the importance of antibiotic resistance and the high prevalence of qnr genes found in this study , furthur studies need to be carried out on qnr resistance genes in the regional and national dimension.

Acinetobacter baumannii is an opportunistic pathogen that has acquired a high rate of antibiotic resistance. Identification of the major elements increasing the expression of resistance genes while having a role in their transmission, can help us control the A. baumannii infections. This study aimed to determine the prevalence of ISAba2 in A. baumannii strains which include group D beta-lactamase genes among hospitalized patients.
From August 2014 to April 2015, 105 A. baumannii strains were collected from different clinical samples of patients in 5 hospitals in Tehran. The confirmation of strains was done by phenotypical tests and existence of blaOXA-51-like gene. Antibiotic susceptibility pattern of the isolates were performed by Disc Diffusion Test (DDT) and Minimum Inhibitory Concentration (MIC) according to the CLSI. ESBL producing strains were recognized with Combined Disc Diffusion Test (CDDT) while the presence of OXA genes and ISAba1and ISAba2 were analyzed using PCR reactions.
The result of this study showed that the highest and lowest rates of antibiotic resistance belonged to cefotaxim (100%) and colistin (99.05%), respectively. A total of 55 isolates (54.5%) were capable of producing ESBL. Unlike the blaOXA-58-like gene, which was not found in any of the isolates, blaOXA-51-like- was present among all the isolates.. Prevalence of blaOXA-23-like and blaOXA-24-like genes were 103 (98.09%) and 68 (64.76%), respectively and the frequency of ISAba1 and ISAba2 were 105 (100%) and 97 (92.36%), respectively.
The existence of additional elements as effective factors, can increase the expression of resistance genes and, therefore, help them to be mobile and transmitted between bacteria. Determination of these elements is, therefore, necessary for controlling infections.

Staphylococcus aureus adhesion factors can reinforce the pathogenicity of the bacteria. The aim of this study was to identify adhesion factors among clinical isolates of methicillin-resistant S. aureus and determine the association between these factors and antibiotic resistance patterns.
In an analytical study from October 2016 to April 2017, 302 clinical isolates of S. aureus were confirmed by biochemical tests. Methicillin-resistant strains were determined by phenotypic methods. Multiplex PCR method was used to identify adhesion factors. In this way, bbp, cna, eno and ebpS genes were identified among different isolates.
A total of 302 clinical isolates of S. aureus were isolated from different clinical samples including wound, blood, urine, trachea, catheter, swabs. Of 302 isolates, 123 were methicillin resistant and 73.53% and 75.7% of the isolates were resistant to erythromycin and penicillin, respectively. The incidence of resistance genes among among methicillin resistant S. aureus isolates were as follows: bbp (10 isolates: 6.89%), cna (6 isolates: 13.4%), eno (28 isolates: 19.31%) and ebpS (19 isolates: 13.1%),. There was a significant correlation between the antibiotic resistance patterns and the frequency of adhesion factors (P≤0.05).
According to the results, there was a significant correlation between adhesion factors and antibiotic resistance among methicillin-resistant isolates of S. aureus.

Cholera is a lethal diarrheal disease that cause by Vibrio cholerae. Cholera toxin and colonization factor pili (tcpA) are the major virulence factor in V.cholerae pathogenesis. The B subunit of the enterotoxin )ctxB) which is responsible for toxin binding to eukaryotic cells and toxin-coregulated pili A (tcpA) that is essential for V.cholerae colonization, have immunogenic properties. Chimeric proteins carrying epitopes, linkers or adjuvant sequences could increase immunogenicity for recombinant antigens and can also elicit broad immune responses. The aim of this study was to design am immunogen against adherence and toxicity of V.cholorae.
ctxB and tcpA genes were analyzed for rare codons and gene optimization was performed using optimization software In 2017. The half-life and protein instability index was determined. Secondary and tertiary structure was predicted and evaluated. Linear and conformational epitopes were predicted. Recombinant pET28a/chimeric gene plasmid was transformed to E.coli BL21 DE3 and expression was induced with Isopropyl β-D-1-thiogalactopyranoside (IPTG). The protein expression was evaluated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE).
Chimeric protein instability index was 24.04 and the codon adaptation index of chimeric constructs increased to 0.9. The tertiary predicted structure of the chimeric proteins confirmed and mRNA was stable. Conformational and linear epitopes were seen in both domains of the chimeric protein. Restriction analysis confirmed cloning of the gene into pET28a vector. Expression of recombinant protein in E.coli led to the production of chimeric protein with 37 k Da molecular weight.
According to the results of bioinformatics and recombinant protein expression, the design chimeric protein could be used as an immunogen to evaluate the immunity against cholera.

Microorganisms within biofilms,, formed on medical devices in the body are highly resistant to antimicrobial compounds and host responses and play a major role in nosocomial infections, especially urinary tract infections (UTIs). Uropathogenic Escherichia coli (UPEC) causes 50% of the hospital-acquired urinary tract infections and is capable to form biofilm in the bladder epithelium which plays an important role in its pathogenesisThe identification of biofilm producing UPEC strains by routine laboratory methods is important for the better understanding of the pathogenesis of this bacterium in UTIs.
A total of 100 UPEC strains were collected from patients with UTIs in a hospital inTehran in 2016 and diagnosed by biochemical tests and the ability of biofilm formation was determined by Tissue Culture Plate (TCP), tube method (TM) and Congo red agar (CRA) methods. Sensitivity and specificity of methods were determined.
In tube method, 23% of the isolates formed strong and 59% formed weak biofilm. In Tissue Culture Plate method 40%, 22% and 28% of isolates formed strong, moderate and weak biofilm respectively and 10% were biofilm negative. According to the Congo red agar method only 4% of the isolates formed strong biofilm, 65% and 31% respectively had a weak biofilm and no biofilm. The sensitivity and specificity of Congo red agar and Tube methods were 39.1%, 50.9% and their features were 78.3%, 79.7% respectively.
The results showed that Tissue Culture Plate method is important for the determination of UPEC biofilm formation. Tube method and Congo red agar are not reliable methods for this purpose.

Due to its self-assembly properties on variety of surfaces and creating regular functional groups, surface layer protein isolated from bacteria, has significant applications in the field of nanobiotechnology such as biosensor production, targeting drug delivery systems and tissue engineering. In this research, optimization of discontinuous culture medium compositions for the production of HPI surface layer protein from Deinococcus radiodurans R1 strain was performed using the response surface (RSM) method.
In 2016, culture medium for 16 designed experiments with fractional factorial analysis (FFA) was prepared and effective factors among six variables of the discontinuous culture medium was investigated for the production of surface layer proteins of D.radiodurans R1. Twenty experiments were then designed for the optimization of effective variables using central composite design (CCD) method. Surface protein purity was assessed using SDS-PAGE analysis and its concentration was calculated via Bradford method.
The optimized medium containing 13.36 g/L glucose, 5 g/L yeast extraction, 5 g/L tryptone, 2 g/L HEPES buffer, 0.55 MgSO4*7H2O, 0.0368 g/L MnCl2*4 H2O, was determined. Wet cellular mass was found as 16.87 g/L, which is 24% more than TGY basic medium and 74% much more than TYG culture medium including NaCl.
Results of the Bradford method demonstrated that the concentration of surface layer protein HPI isolated from D. radiodurans R1 was 5.6 mg which was more than twice of that using 1liter of basic TGY medium.

Antibiotics are known as the most useful and effective drugs in the treatment of infectious diseases in humans and animals. The indiscriminate use of antibiotics directly or indirectly, for instance through raw animal products such as milk, can cause health problems in human societies. The specific aim of this study was to determine the level of antibiotic residue in raw and pasteurized milk in Gilan province.
In this study 30 pasteurized milk samples of randomly selected brands and 570 raw cow milk samples from milk collection centers in 15 cities of Gilan province were collected. The samples were analyzed by coupon test.
Results and Antibiotic residue was observed in 179 (31.4%) and 18 (60%) samples out of the 570 raw and pasteurized cow milk samples, respectively.. According to dairy per capita consumption in Gilan province, this rate of contamination affects a considerable part of the population. It can therefore be concluded that the contamination of dairy products to residual antibiotic can be considered an important factor threatening human health and should be considered in the quality control of milk and dairy products.

Trichomoniasis is one of the most common sexually transmitted diseases caused by the parasite Trichomonas vaginalis. The most important point about this infection is diagnosis and treatment of the patients and their sexual partners, in order to prevent infection spread. In the present study direct smear, staining, culture and indirect immunofluorescence antibody methods were used for the diagnosis of this organism.
This study was conducted on 120 women who were referred to healthcare centers of Rasht city during April to September 2015. The histories of the patients were collected as questionnaires. Biopsies of the cervical and posterior vaginal secretions were collected for direct smear and the slides were prepared for H & E staining. The samples were cultured in TYI-S-33 medium as well asbeing tested for the presence of antibody through indirect immunofluorescence method.
Results and Out of the 120 samples that were checked, the results of different methods showed that among the diagnostic methods, except for indirect immunofluorescence, only one infected specimen of T. vaginalis was positive in culture (0.83%). By using indirect immunofluorescence antibody test, the number of patients detected as infected with T. vaginalis were increased to seven (5.83%). The sexually transmitted diseases represent similar symptoms and signs and it is therefore better that gynecologists use the laboratory diagnostic results in order to prescribe suitable drugs. Diagnosis using culture medium is a lengthy process whilst most of the other methods used in this study have a low sensitivity and specificity. It is therefore recommended to use immunofluorescence antibody test for the diagnosis of T. vaginalis infections since it has a high sensitivity and specificity and is also relatively easy to use.