ملیحه طالبی

Considering the importance of potato in the economy and human nutrition, the need to produce healthy seeds through tissue culture in order to increase the quality of the tuber and ultimately maintain the yield of the product is noticeable. In this regard, the aim of the present study is to evaluate the morphological and biochemical traits in the seedlings of four early and late potato cultivars under in vitro conditions. Four commercial varieties of potato were cultivated as single-node microspecimens in MS culture medium without any plant growth regulators. Seedlings grew after 5 weeks. Seedlings were evaluated in terms of morphological traits (number of seedlings produced from one seedling, stem length, number of branches, nodes, roots and micro-gland) as well as biochemical traits (chlorophyll a, b, carotenoid, anthocyanin, catalase enzyme activity and polyphenol oxidase enzyme activity). In morphological traits, late cultivar Satina, number of seedlings and stem length, and early cultivar Sante showed more roots than other cultivars. In the study of biochemical traits, the late cultivar Agria was superior to other cultivars in terms of the amount of pigments and catalase enzyme. In the same vegetative conditions, different cultivars have different potential in vegetative and biochemical traits. The growth pattern of different genotypes is determined by the synthesis of food and different levels of internal hormones and the balance between them, and as a result, they give different responses to the conditions of the culture environment. The present study showed that in the same vegetative conditions, the early cultivars of Satina in terms of vegetative traits and Agria in terms of the amount of pigments can be selected for mass cultivation.

 The healthy people’s fecal flora in the community represents a large potential reservoir. Therefore, the current study aimed to detect antibiotic resistance patterns and virulence factors in Klebsiella pneumoniae isolated from healthy volunteers’ feces.

 Three hundred and fifty stool specimens were collected from sales rep healthy individuals referring to the Northwest Tehran Health Centers to get a health card. Bacterial isolation, identification, and antimicrobial susceptibility testing were conducted according to the routine instructions. In addition, polymerase chain reaction (PCR) was used to detect the genetic factors responsible for producing extended-spectrum β-lactamases (ESBLs: SHV, TEM, and CTX-M) blaKPC and other virulence genes.

 Among fecal samples analyzed, 60 (17.1%) K. pneumoniae were isolated. The results demonstrated that the highest resistance rate was related to piperacillin-tazobactam (n=25, 41.6%), followed by and meropenem (n=17, 28.8%) and co-trimoxazole (n=11, 18.3%), respectively. Also, all strains were susceptible to amikacin, gentamicin, and imipenem. The PCR results of the virulence gene showed that 95% (n=57) of isolates were positive for fimH gene, 93.33% (n=56) for BssS gene, 27 (45%) for rmpA gene. The PCR results for antibiotic resistance genes showed that 41.66% (n=25) had blaTEM gene, 38.33% (n=23) blaCTX-M gene, 35% (n=21) blaSHV gene and 3.33% (n=2) isolates had blaKPC gene, and none of these isolates carried magA gene.

 Antibiotic resistance was common among K. pneumoniae isolated from healthy volunteers’ feces who participated in this study. Transmission of resistant bacteria and plasmids through oral-fecal sources threats to the public, which could complicate treatment options for community-acquired infections caused by K. pneumoniae.

 Shigella flexneri is a highly contagious Gram-negative bacterium that causes severe diarrhea, especially in children under ten years old. The biofilm formation in this species increases its resistance to antibiotics. Given the important role of toxin-antitoxin (TA) systems in the stability and survival of bacteria under stress condition, this study was aimed to evaluate the expression of genes encoding TA systems and Lon protease (lonp) as the main protein regulating the expression and function of these systems in this microorganism in terms of biofilm formation.

 In this study, the standard Shigella flexneri ATCC 12022 was used. After the bacteria culture on the specific culture medium, the ability to form biofilm was quantitatively evaluated by microtiter plate method. Then, the expression level of the mentioned genes was assessed compared to the control group using real-time PCR.

 The results of microtiter plate test showed that the studied Shigella flexneri was a strong biofilm strain. The qPCR results showed an increase in gene expression of the studied toxins and Lon protease at 8 and 24 h following biofilm formation induction (P<0.01).

 Due to the significant increase in the expression of the studied genes, especially Lon protease, GNAT and maz toxins at 24 h after biofilm formation, they can be potentially used as antimicrobial targets in new studies.

Intestinal colonization of the newborn is essential for establishment, maturation and maintenance of the gut mucosal barrier. The greatest difference between the microbiota of breast milk and Infant formula infants feeding is the numbers and species composition of Bifidobacteria. In this study, we tried to identify the native Bifidobacterium isolates obtained from the human’s breast milk and the feces of their paired infants in rural areas of Markazi Province in 2015. In this descriptive study, 28 samples from mothers’ milk and 28 samples from paired infants feces were collected and cultured. Suspicious colonies were picked up and confirmed by phenotypic identification and finally specific primers were designed for genotypic detection by PCR assay. Finally, the results were analyzed using spss18 software. Findings: In this study, amongst Fifty-six samples, 31 (55%) different Bifidobacterium species including 15 (36%) B. bifidum, 14 (34%) B. longum, and, 12 (29%) B. 1 were isolated. Out of which, 12 (29%) isolates including B. longum (6), B. breve (4) and B. bifidum (2) were shared between six mother-infant pairs. The correlation coefficient of bifidobacteria isolated from breast milk against their feces was +0.821 (p-value <0.05). By observing the 29 percent contribution and the positive correlation coefficient between breast milk and fecal bifidobacterium in our study, it probably be acknowledged that the main source of intestinal bifidobacterium in the early stages of birth is breast milk.

One of the major problems for the isolation and detection of S. pneumoniae from clinical specimens, high sensitivity, rapid autolysis and thus the inability to hold isolates of pneumococcus. So, it is essential to use specific techniques for the preservation of the organism. In this study several different cultures for S. pneumoniae isolates were compared and evaluated.
In 2014, 2 ATCC standard , 30 clinical, and 30 normal flora pneumococcal available isolates were selected from a previous study. Dorset egg medium was prepared for midterm preservation, three storage environments, including Skim milk-Tryptone-Glucose-Glycerin (STGG), nutrient broth enriched and Todd Hewitt Broth (THB) was constructed to long-term preservation, and their performance on maintenance pneumococcal isolates was assessed.
Results and 95% of the isolates cultured on Dorset after 70 days and 80% after four months later had the ability to grow. All three long-term storage environment, had a good performance for one year but enriched nutrient broth could keep bacteria with but better-quality up to 2 years. There is no difference between isolates from the patients and isolates from normal flora to survive in the environment. Also aggressive origin of iclinical isolates had no effect on their survival rate. Dorset egg (DE) medium can be considered as a simple, low cost and efficient, medium for midterm preservation and enriched nutrient broth for long term storage of pneumococcal isolates in clinical laboratories.

With increase Staphylococcus epidermidis infections, discrimination between invasive and non-invasive S. epidermidis strains and determination of drug resistance, for diagnosis and treatment is important.
From August 2014 to March 2015, 123 strains isolated from patients and medical instruments from Ali Asghar and Hazrat Rasoul hospitals were used to discriminate invasive and contaminating S. epidermidis strains by ica, atlE, agrA, sarA, and mecA genes by Multiplex PCR method. Also, according to the CLSI standards, resistance to cefoxitin, linzeolid, clindamycin, erythromycin and tetracycline were tested by disk diffusion method and vancomycin E-test method.
prevalence of ica and mecA genes were 85% and 75% in invasive strains and 20% and 51% in contaminating strains, respectively. The resistance level to cefoxitin, tetracycline, clindamycin and erythromycin antibiotics in invasive strains were: 75℅, 35℅, 37℅, 76℅ and in contaminating strains were; 51℅, 40℅, 30℅, 64℅, respectively. Resistance to vancomycin and linezolid was not observed in this study.
This study shown that ica gene can be used as a suitable marker for discrimination between invasive and contaminating isolates. Also, vancomycin is a better choice for the treatment of resistant patients to methicillin.

Enterococci are among the normal microbial flora in human and animals digestive tract. The nosocomial pathogenicity of enterococci has emerged in recent years and has caused great concern due to developing resistance to many antimicrobial agents. The aim of this study was to investigate and identify the prevalence of VRE (vancomycin resistant enterococcus) within Enterococci isolates obtained from different parts of the hospital. Putative Enterococci (n=120) were isolated on Membrane Filter Enterococcus Selective Agar Medium and supplemented with 2, 4 and 8 µgr/ml vancomycin in medical samples. A total isolates passed the standard biochemistry tests for the genus and species as well as their specific primers. The antibiotic susceptibility was determined by the disc diffusion method for 8 antibiotics. Microbiologically-influenced corrosion (MIC) of vancomycin was also done using Agar-dilution assay by CLSI recommendations. Results showed that 38 and 84 of the isolates were E. faecium and E.faecalis, respectively. According to antimicrobial susceptibility tests 45, 88, 103, 42, 83, 73, 54 and 95 of the isolates were resistant to vancomycin, tetracycline, gentamicin, chloramphenicol, ciprofloxacin, penicillin, ampicillin and erythromycin, respectively. MIC test on 70% of the isolates was>256 µgr/ml. Despite the fact that the prevalence of VRE strains belongs to two species, E. faecium had high resistance to a broad range of antibiotics. The results of this study indicate the important role of medical samples as reservoirs of resistance elements. Early detection of VRE with their virulence trait will help in preventing the spread of vancomycin resistant enterococcus species and urgent infection control is required in hospital setting

Congenital hypothyroidism (CH) is one of the most common causes of preventable growth disorders and mental retardation، but can be prevented by early diagnosis and treatment. The aim of this study was to evaluate the antropomethric indices of children with congenital hypothyroidism and compare with healthy children at the age of school. This retrospective cohort study was conducted on 30 children with CH who were diagnosed during the CH screening program in 2006-2007 and 30 healthy children were compared. The mean of weight (3. 31± 0. 31)، height (50. 26 ± 2. 08) and head circumference (34. 51 ± 1. 42) at birth were not significantly different from healthy children. The mean of weight in children with CH at the age of school (25. 47 ± 17. 1) and healthy children was not significantly different but the mean of height in studied patients (117. 3± 6. 00) was significantly (p<0. 001) lower than the healthy children (123. 3± 5. 8). In this study the mean of weight in studied patients at the age of school wasn’t significantly different from the healthy children but the mean of height was significantly different.

Streptococcus pneumoniae, is one of the most important bacterial pathogens and a member of viridians streptococci group. Accurate identification and differentiation of this form of bacteria from other relative streptococci, is the base of epidemiological study of this type of organism. The aim of this study was to evaluate the accuracy of detection of Streptococcus pneumoniae in clinical laboratories in Tehran, by using phenotypic and genotypic methods. A total number of 110 isolates, identified as pneumococci by some clinical laboratories in Tehran, were collected between March 2010 to May 2012.After isolating the colonies, biochemical identification tests by optochin susceptibility (Mast) and bile solubility (direct method) methods were performed. After DNA extraction, PCR was performed to define lytA gene as a molecular identification for Streptococcus pneumonia. After re-identifying the isolates, fifty of them were determined as true pneumococci, and other remaining sixty isolates were identified as: three gram negative coccobacilli, seven non alpha hemolytic streptococci, and fifty Viridans streptococci. Most of misidentifications were related to respiratory and eye infecting streptococci. Unlike non pneumococcal isolates, all 50 pneumococcal isolates were positive for lytA gene. There was 55% error in detection of pneumococci in this study. The use of optochin susceptibility test as the sole detection tool and also lack of supplemental tests and proper quality controlling, are the main causes of failure in diagnosing pneumococci in Iran. Misidentifications may result in incorrect epidemiological data gathering, unnecessary treatment, and false increased antibiotic resistance reports for this organism. Regarding the high incidence of inaccuracies in defining this specific type of microorganism, we suggest the presence of a clinical microbiologist in the hospital laboratories to perform the right diagnostic tests and quality controlling would be essential.

Soil colloid particles influence soil chemical and physical properties by their surface electrical charge. With respect to the importance of this issue from both agricultural and environmental points of view, charging behavior of a kaolinite sample was studied in the pH range of 4 to 10 and at three background electrolyte concentrations, including 0.005, 0.05, 0.5 M NaCl, by potentiometric titration. Using a combination of mass and electrolyte titrations, kaolinite point of zero charge (PZC) was determined to be at pH=7.6. Increase in pH from the initial value of 4 caused at first a gradual decrease in positive surface charge and then a gradual increase in negative surface charge, indicating a net positive surface charge at pHPZC. Increase in ionic strength reduced positive surface charge at pHPZC. The adverse effect of ionic strength on the surface charge at pH

Keywords: adsorption, ion, exchange, point of zero charge, surface charge

Seizure is defined as a clinical state that represents with abnormal and paroxysmal discharges in the cerebral cortex. Epilepsy refers to a neurological disorder which a patient experiences two or more seizures through cut life. The related data regarding the prevalence of epilepsy are controversial. The aim of the present study was to assess the prevalence of epilepsy in Tabriz, IRAN. In a descriptive study, 4300 individuals from Tabriz were studied using door-to-door visits. History assessment and physical examination were carried out in probable epilepsy cases and findings were assessed. Of 4300 individuals, 46.9% were male and 53.1% were female. Eight individuals (0.18%) with a prevalence of 1.86 per 1000 people suffered from epilepsy. There was epilepsy prevalence of 2.47 per 1000 people and 1.31 per 1000 people in male and female, respectively. Epilepsy prevalence was 1.74 per 1000 people in the 0-9 -year-old group, 2.94 per 1000 people in 20-29 -year-old group, 2.84 per 1000 people in 30-39 –year-old group, 3 per 1000 people in 50-59 year-old-group, and 23.8 per 1000 people in ≥80 –year-old group. Of the epileptic patients, 62.5% were male with a mean age of 35.79±24.69 years. Tonic (37.5%) and tonic- clonic seizure (25%) were found the most prevalent types. Total epilepsy prevalence was lower than those reported in other region. Epilepsy prevalence in males was higher than females, which differs from some other studies. Such difference is likely due to regional differences and difference in health level and people information in this region.

Urinary tract infection is the most common nosocomial infection worldwide. Microorganisms causing urinary tract infections are resistant to most of the antibiotics. Pseudomonas aeruginosa (P. aeruginosa) is one of the major causes of nosocomial infections and its antibiotic resistance leads to medical implications associated with urinary tract infections. The aim of this study was to assess the prevalence of P. aeruginosa strains to identify their in-vitro susceptibility to antimicrobial agents and to determine genetic diversity of them.

Urine samples were obtained from catheterized patients in Shohada and Labafi Nejad hospitals, Tehran, Iran, and cultured by standard loop method. The cultures with more than 105 CFU/ml were assumed as positive. After identification of bacterial species by biochemical tests, susceptibility of each isolate was assessed by disk diffusion method according to Clinical and Laboratory Standards Institute (CLSI) guidelines. In order to analyze bacterial genotypic diversity, pulsed-field gel electrophoresis (PFGE) was performed.

116 out of 163 urine samples were positive for bacterial isolates. Pseudomonas species were placed in third step of the most frequent isolates. Antibiotic sensitivity was observed against most of antimicrobial agents. Some of strains were genetically similar.

This study revealed that isolated strains were sensitive to wide range of antibiotic agents. In addition, common type strains were responsible of causing inter- and intra-hospital urinary tract infections in catheterized patients.

Renal transplantation is the treatment of choice in patients with end-stage renal disease. Urinary tract infection (UTI) is one of the most common complications after renal transplantation and it has serious consequences. The aim of this study was assessing UTIs in renal transplanted patients and evaluation of risk factors associated with post-transplant UTI. In this prospective study، 173 patients (48 hospitalized patients and 125 outpatients) were enrolled in this study. These renal transplant recipients evaluated for bacterial urinary tract infection in urology research center at Sina Hospital. After collecting urine samples from symptomatic and asymptomatic patients، urinalysis and colony count were performed. Identification of bacteria was performed by routine microbiological tests in the Department of Pathobiology، School of Public Health، Tehran، Iran، in 2011. UTI was observed in 47 patients and the most prevalent microorganism was Escherichia coli (E. coli) 18 (38. 2%). Nearly 71% of UTI cases were diagnosed during the first three months post transplantation. Risk factors for post transplant UTI were female gender، age، length of hospitalization and diabetes mellitus. Female patients were more susceptible than males (OR=0. 50 and P=0. 047) to infection. There were no significant difference between diabetes mellitus and UTI. Most of the isolated bacteria were susceptible to imipenem and resistant to tetracycline and trimethoprim- sulfamethoxazole. Our study confirmed that bacterial infections remain as the most common infectious complication in the early post-transplant period، and antibiogram rather than empirical treatment is needed to find the best effective antibiotics. Moreover، risk factors such as female gender، increased age and length of hospitalization are predisposing factors to increased urinary tract infection in renal transplantation.

Acinetobacter baumannii is an important human pathogen that has been a focus of attention in recent years. These bacteria are a leading cause of therapeutic resistant nosocomial infections especially in burned or hospitalized patients in intensive care Units. The aim of this study was to isolate the Acinetobacter baumannii species from the wounds of burned patients and to determine antimicrobial resistance pattern of these bacteria for selection of appropriate antibiotics. Samples were collected from patients and transferred to the laboratory under standard conditions. Bacteria were isolated and purified by conventional culture methods. Identification of bacterial species was performed by standard biochemical tests. The isolates that were identified as Acinetobacter baumannii were subsequently tested for antibiotic resistance by the disk diffusion agar method for 17 different antibiotics. The tests were carried out on Muller Hinton agar (MHA) plates and incubated at 35˚C for 18 hrs. The minimum inhibition concentrations were determined for 5 common therapeutic antibiotics. Out of the 65 clinical Acinetobacter baumannii isolates collected، 61 (94%) were multi drug resistant (MDR). Ceftazidime and aztronam (98%) were the most effective antibiotics against Acinetobacter baumannii. To determine the MIC، the highest levels of antibiotic resistance were seen against ceftazidime، cefepime، and ciprofloxacin. Our results confirm the high prevalence of Acinetobacter baumannii resistant isolates and the ensuing therapeutic problems in Iran. Determination of the resistance patterns of these bacteria according to MIC is necessary، and it can be especially helpful in treatment of burned patients.

Congenital hypothyroidism (CH) is one of the most common preventable causes of mental retardation throughout the world. The aim of this study was to investigate the prevalence of CH among newborns of East Azerbaijan province in 2009-2010. This descriptive analytic study was performed by using census cross- sectional method on 62459 neonates in East Azerbaijan province from 21st March 2009 to 20th March 2010. Blood samples were taken within the 3rd -5th days of life by lancet sticking of neonatal heel and transferred to filter papers for measuring TSH level. In the case of TSH ≥ 5mu/l, additional confirmation tests were done and confirmed cases based on serum confirmation test (TSH>10 mu/l or T4<6.5mg/dl) underwent treatment according to the national guidelines. Data were analyzed by SPSS software. The recall rate was 2.5%. Total number of patients was 94, including 55 males (58.5%) and 39 females (41.5%). Prevalence in males, females and overall was respectively 1:588, 1:769 and 1:666, with no significant difference. Seasonal prevalence was respectively 1:833, 1:943, 1:492 and 1:588 that shows no significant difference among four seasons. The highest prevalence was in Tabriz (27.7%) and the lowest in Azarshahr (0%) and Kaleibar (0%). Mean maternal age of affected neonates was 26.22 ± 6.2 years. Mean neonate's weight was 3500 ± 652 grams. In 76% of neonates time of sampling was in the 3rd -5th days of life and in 89% of them test result was announced before 13th day. Mean treatment onset based on neonate's age was 2.7±1 day. In 97.5% of screened neonates TSH level was less than 5 mu/l. The prevalence of CH in East Azerbaijan province is significantly higher than national and worldwide levels that requires continuation and reinforcement of neonatal screening programs. On the other hand, comprehensive and complementary studies for recognizing relevant factors are among priorities of health system research in this province.

Enterococci are normal microflora of the humans. They are identified as opportunistic pathogens and they are among the three major factors of hospital infections. Enterococci are able to form biofilms on the biotic and abiotic surfaces and this ability is one of the important factors to pathogenesis. The purpose of the present study was to evaluate biofilm formation and evaluation of antibiotic resistance among Enterococcus faecalis (E. f) isolates from clinical and environmental isolates in Tehran hospitals.

In total, 90 isolates of Enterococcus faecalis including 58 clinical and 32 environmental isolates of (E.F) were collected from 2 hospitals in Tehran. All enterococcal species isolates were identified by species-specific PCR. Antibiotic resistance pattern of 90 isolates of (E. f) isolates was determined by disk diffusion method according to the CLSI guidelines. Biofilm formation of (E. f) isolates was evaluated by microtiter plates method.

The highest resistant percents of clinical (E. f) isolates against tetracycline, erythromycin, co-trimoxazole, ciprofloxacin and gentamicin were 86%, 62%, 69%, 69% and 64%, respectively. Among environmental isolates the resistant percents were 75%, 44%, 25%, 22% and 25%, respectively. According to biofilm formation assay, 72% and 84.5% of clinical and environmental (E. f) isolates were positive, respectively. Samples that were able to form biofilms showed more antibiotic resistance than those that are not able to form biofilms.

The results of this study indicate high prevalence of antibiotic resistance and the ability of biofilm formation among Enterococcus faecalis. Considering the role of biofilms in increased antibiotic resistance and virulence, it is needed to carry out necessary measure to eliminate suitable conditions for biofilm formation which act as a shield against various conditions, including the host immune system and antibiotics.

Enterococci are natural inhabitants of the gastrointestinal tract of humans and animals. Over the past decade, enterococci have become one of the leading causes of nosocomial infections,because they have acquired resistance to many antimicrobial agents such as vancomycin and gentamicin.Development of high-level gentamicin resistance among enterococci represents a serious therapeutic problem as it precludes synergy between aminoglycosides and cell-wall active agents. High-level gentamicin resistance (MIC ≥ 500 mg/ml) in enterococci is predominantly mediated by aac (6')-Ie-aph (2'')-Ia gene.. The aim of present study was determination of high level gentamicin resistance in Enterococcus species isolated fromhealthy human in Tehran. After enrichment of the fecal samples collected from healthy volunteers in BHI broth containing gentamicin, the isolates were subcultured on m-Enterococcus agar containing gentamicin. The isolates were identified to the genus and species levels and MIC was determined. Antibiotic susceptibility of the isolates was tested by agar diffusion method for 8 various antibiotics. The aac(6')-Ie-aph(2'')-Ia gene was identified by PCR technique. gentamicin resistant enterococci(GRE) were isolated from 76(15.2%) of 500 fecal samples. The isolated species were: E. faecalis 45(59.2%), E. faecium 29(38.1%) and E. gallinarum 2(2.63%). GRE isolates were highly resistant to gentamicin(MIC ≥ 500 μg/ml). Eleven different antimicrobial resistance patterns were observed in this study. All of isolates carried the aac(6')-Ie-aph(2'')-Ia resistance gene. These results represent a rather high prevalence of gentamicin resistance enterococci as a normal flora in the community. The aac(6')-Ie-aph(2'')-Ia gene was the most common gene among the gentamicinresistant isolates evaluated in this stud.

Gram positive bacteria, particularly, Staphylococcus aureus, coagulase negative staphylococci and enterococci are of particular concern in hospitals. But there has been increasing concern about the development of vancomycin resistant enterococci and MRSA strains with reduced susceptibility to vancomycin over the last decade. Therefore, the present study was carried out to confirm the identification of vancomycin resistant gram positive cocci, to determine antibiotic resistance pattern and tostudy vancomycin resistance genes. The isolates from clinical samples were collected from hospitalized patients and outpatients in Tehran. Gram positive cocci species identification was performed by using conventional tests and PCR using specific primers. VRE isolates were subjected to antibiotic susceptibility testing, MICs of vancomycin were determined by the E-test method. Determination of vancomycin resistance genes, vanA and vanB were performed with PCR. Confirmation of transposons was performed with specific primers for vanS. Out of 1030 gram positive isolates, none of the staphylococci or streptococci isolates were resistant to vancomycin. Most of vancomycin resistant isolates in this study were VRE. faecium (96%) and harbored vanA. All of the isolates were positive for vanS the conserved fragment of transposon and carried the identical digestion pattern like type strain. According to the results of this study, all of the vancomycin resistant isolates were enterococcus spp. Vancomycin resistant enterococci itself is now a major and largely untreatable infection, and can pass the vancomycin resistance genes to the other highly virulent gram positive cocci.