MEDICAL LABORATORY JOURNAL
Year:2016 | Volume:10 | Issue:6|Papers Count:10

Background and Objective: Streptococcus pneumoniae is one of the leading causes of death among children worldwide. Nasopharyngeal colonization in children can spread pneumococcal infections in the community. This study aimed to evaluate the prevalence ofS. pneumoniae strains isolated from healthy pharyngeal carriers less than 5 years of age.Methods: This cross-sectional descriptive study was performed on 150 children under 5 years old in the city of Shiraz. After nasopharyngeal swab sampling, the samples were cultured on blood agar containing 5% sheep blood. The cultures were incubated at 37 °C for 24 h. Primary identification was carried out using optochin sensitivity testing, bile solubility testing and gram staining. Molecular identification ofS. pneumoniae strains was done usinglytA gene-specific primers.Results: Of the 150 samples collected from healthy children, 24.67% were pharyngeal carriers ofS. pneumoniae. The highest frequency of pneumococcal strains was related to male carriers (n=22, 59.46%) and the children aged 1-2 years (n=11, 29.73%).The results showed no significant association between the prevalence of pharyngeal carriage and gender or age.Conclusion: Given the increasing rate of pharyngeal carriage of S. pneumoniae in children as a risk factor for respiratory tract infections, there is a need for further monitoring of the circulating serotypes and investigation of antibiotic-resistance mechanisms.

Background and Objective: Several studies have shown the antimicrobial activity of lactobacilli against Salmonella enterica (serotype typhimurium). The aim of this study was to evaluate the inhibitory potential of metabolites produced by probiotic culture ofLactobacillus casei against S. typhimurium and its impact on S. typhimurium motility and biofilm formation.Methods: In order to evaluate the impact of the metabolites, L. casei cell-free culture supernatant (CFCS) was collected by centrifugation of L. casei secondary cultures.Effectiveness of the CFCS against Salmonella was evaluated by the well-diffusion method. In addition, in vitro effect of this treatment on motility in Swarm agar and biofilm formation by the bacteria was investigated.Results: Inhibition zone diameters of S. typhimurium were 0.83 and 12.1 mm at concentrations of 50 and 100μl of Lactobacillus CFCS against the log4 of S. typhimurium, respectively. Moreover, CFCS treatment inhibited the motility and biofilm formation by Salmonella. Concentrations of 5% and 10% were determined as the minimum inhibitory concentrations for motility and biofilm formation byS. typhimurium. Furthermore, effectiveness of the CFCS against Salmonella was dose-dependent (P<0.05).Conclusion: L. casei CFCS is able to inhibit the growth, motility and biofilm formation inS. typhimurium.

Background and Objective: Biofilms are community of bacteria that attach to inanimate surfaces or living tissues via production of extracellular polymers and exopolysaccharide matrix. Microbial biofilms on various surfaces of the hospital environment are considered as a reservoir of infection spread. The present study aimed to evaluate the disinfecting effect of benzalkonium chloride on some bacterial isolates causing nosocomial infections.Methods: First, 13 isolates from four bacteria including Pseudomonas aeruginosa, Staphylococcus aureus, Acinetobacterand Enterobacter were obtained from Microbiology Laboratory of Al-Zahra Hospital in Isfahan, Iran. The samples were transferred to Microbiology Laboratory of Faculty of Veterinary Medicine of Shahrekord University for testing. Evaluation of biofilm formation and determination of minimum inhibitory concentration (MIC) of the disinfectant and effect of the disinfectant on planktonic growth and biofilm formation were performed.Results: All bacterial isolates (52 cases) produced biofilm. Mean MIC of benzalkonium chloride forP. aeruginosa, S. aureus, Enterobacter and Acinetobacter was 0.14, 0.2, 0.18, 0.17 g/ml, respectively. Planktonic growth of all four bacteria was inhibited at concentrations of 2MIC, MIC and 1/2MIC. Biofilm was not produced in MIC and 2MIC concentrations, and biofilm formation capability increased by reducing the concentration of benzalkonium chloride.Conclusion: The results show that the use of appropriate concentration of benzalkonium chloride can prevent the growth of different bacterial species, but sub-MIC dose of this disinfectant may stimulate biofilm formation.

Background and Objective: Multipotent placental amniotic membrane mesenchymal stem cells (MSCs) are capable of differentiating into specialized tissues under different conditions. The aim of this study was to induce differentiation of placental amniotic membrane MSCs from NMRI mouse into hepatocytes using liver extract.Methods: Placental amniotic membrane MSCs from a 14-day pregnant female mouse was used in this study. The cells were incubated with trypsin solution, followed by pipetting.The resulting suspension was cultured in 12-well plates. After confirming their mesenchymal nature, differentiation of the aforementioned cells was induced via exposure to 6, 18, 30 and 60μg/ml of liver extract. On the 16th day of treatment, immunocytochemical reaction for albumin and periodic acid-Schiff (PAS) test were performed for detection of hepatocyte-like cells.Results: Change was observed in the shape of differentiating cells from spindle-like shape to polygonal shape. The immunocytochemical reaction of the differentiated cells was positive. PAS staining also confirmed the accumulation of glycogen particles in the aforementioned cells. Concentration of 6μg/ml liver extract was found as the effective dose for induction of differentiation.Conclusion: The findings of this study show that the placental amniotic membranederived MSCs of mouse can differentiate in vitro from spindle-like cells to polygonal hepatocyte-like cells with large nuclei and under the influence of the liver.

Background and Objective: In this study, we compared the susceptibility of Salmonella typhimurium phoPmutant and its parent to stress conditions that the pathogen may encounter in a host.Methods: For this purpose, we used the phoP deletion mutant constructed in our previous study. In order to test the in vitro susceptibility of the mutant to stress factors, the effect of acidic pH, heat, bile salts and polymyxin on growth of the mutant was examined.Then, minimum inhibitory concentration and minimum bactericidal concentration of bile salts and polymyxin were determined.Salmonella typhimurium 14028 was used as the parent strain.Results: The mutant was highly susceptible to bile salts and polymyxin in comparison with the parent strain, but no difference was observed in their susceptibility to acid and heat.Conclusion: This study confirms the role of the phoP in resistance of Salmonella to polymyxin and bile salts. Mutation in thephoP leads to susceptibility of the mutant to bile and cationic antimicrobial peptides.

Background and Objective: The present study aims at investigating the possible effect of 8-week aerobic exercise on undercarboxylated osteocalcin and beta cell function in postmenopausal women.Methods: The study included 20 postmenopausal women with mean weight, height and body mass index of 78.94± 5.72 kg, age 48.69 ± 3.21 years, 160.37 ± 4.12 cm and 30.72± 2.37 kg/m2. The participants were randomly selected and divided into experimental and control groups. Blood samples were taken 48 hours before the experiment and after eight weeks of exercise. Aerobic exercise was performed for eight weeks, three sessions per week with intensity of 65-70% of heart rate. Data analysis for intragroup and intergroup differences was done using paired and independent t-test, respectively. P-values less than 0.05 were considered statistically significant.Results: The level of under carboxylated osteocalcin in the experimental group decreased significantly compared to control group (P<0.049). The level of beta cell function index in the experimental group increased significantly after the 8-week exercise program compared to control group (P<0.014).Conclusion: Exercise increases the level of under carboxylated osteocalcin in postmenopausal women that has important consequences, especially for those at risk of developing diabetes.

Background and Objectives: Cryptosporidium parvum is a coccidian protozoan that causes diarrhea in immunocompromised humans and newborn animals. The severity of the disease depends on the immunological status of the affected. Cryptosporiosis can have lethal effects on immunocompromised individuals such as AIDS patients. About 10% of AIDS patients die following an infection withC. parvum. Since there is no efficient treatment for cryptosporidiosis, there is an urgent need to search for more effective and safer alternatives.IgY is an avian immunoglobulin found in egg yolks. Due to its several advantages, IgY technology has been successfully used in biomedical research on humans and animals in the recent years. In this study, the specific chicken egg yolk antibody (IgY) againstC. parvum whole oocyst antigens was produced and examined.Methods: The effect of specific chicken egg yolk antibody (IgY) against whole oocyst antigens was examined. IgY sample was obtained from eggs of chickens immunized withC.parvumwhole oocyst antigens and analyzed with lysate of C. parvum oocysts by dot blot assay.Results: The IgY was produced with concentration of 9.7 mg/ml. This antibody was able to recognize the whole oocyst antigens until the dilution of 1: 1000, but the best dilution for other immunoassays was 1: 500.Conclusion: Since chicken egg yolk is a cheap and convenient source for mass production of specific antibodies, the use of IgY against whole oocyst antigens could be considered a suitable candidate for passive immunization against cryptosporidiosis in humans and animals.

Background and Objectives: Diabetes is one of the most common endocrine disorders, which is associated with changes in testicular tissue. The present study investigated therapeutic and prophylactic properties of bitter orange (Citrus aurantium) juice on testicular tissue and spermatogenesis process.Methods: Forty streptozotocin-induced diabetic Wistar rats aged three months with mean weight of 170-200 g were divided into 4 groups including 1) control group, 2) diabetic control group, 3) diabetic group receiving 100mg/kgC. aurantium extract and 4) diabetic group receiving 200 mg/kgC. aurantium extract. The extract was administered to the rats for 56 days by gavage. After this period, the rats were anesthetized with ether and then their testes were fixed in 10% formalin for sample preparation. The testicular tissue was examined by haematoxylin and eosin staining under a light microscope with 10 and 40 magnifications. The mean number of Leydig and Sertoli cells, spermatogonia, spermatocytes and spermatids were calculated.Results: A significant decrease was observed in mean weight of left testis in diabetic rats compared to that of controls (P£0.05). The mean weight of testes showed no significant difference in diabetic rats treated with 200 mg/kg of extract compared with the control group. Diabetes reduced the number of spermatogonia, spermatocytes, spermatids and Sertoli cells. The number of cells increased significantly in the diabetic group receiving 200 mg/kg of extract. The spermatocytes and spermatids in both groups treated with the extract increased significantly.Conclusion: This study shows the positive effect of bitter orange extract on complications of diabetes in testicular tissue. Therefore, this extract could be used for therapeutic purposes.

Background and Objective: Although antibiotics are commonly used for treatment of infectious diseases, these treatments are often associated with several problems such as unwanted side effects and resistance to antibiotics. The aim of this study was to evaluate the antibacterial effect of aqueous and alcoholic extracts ofNasturtium officinale on Escherichia coli, Salmonella typhimurium, Staphylococcus aureusand Listeria monocytogenes.Methods: All experiments were performed using the well diffusion method. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the aqueous and alcoholic extracts of N. officinale against the pathogenic bacteria studied were determined by microdilution method.Results: In the well diffusion method, S. aureus and L. monocytogenes were the most sensitive bacteria with MIC of 8mg/ml, while E. coli and S. typhimurium were the most resistant bacteria to the aqueous and alcoholic extracts. In addition, the inhibitory activity of the alcoholic and aqueous extracts ofN. officinale was higher against gram-positive bacteria compared to gram-negatives. The lowest MIC (6.25mg/ml) and MBC (12.5 mg/ml) of the plant extract were againstS. aureus.Conclusion: The aqueous and alcoholic extracts of N. officinale affect the growth of gram-positive bacteria (S. aureus and L. monocytogenes) but not the gram-negatives (S. typhimuriumand E. coli). These extract could be used for treatment of infections.

Background and Objectives: Many species of Ziziphora have been used in traditional medicine in the Azarbaijan region, northwest of Iran. This study aimed to determine antibacterial activity of essential oil and methanol extract ofZiziphora tenuior on some pathogenic bacteria isolated from urogenital tract infections.Methods: The essential oil and methanol extract of Z. tenuior were obtained by Clevenger and maceration methods. Under sterile conditions, the required amount of urine was taken from patients referred toa number of clinics in Tabriz during 2014. After identification of the isolates using standard microbiological methods, antimicrobial effects of the essential oil and methanol extract of the plant on the isolates were evaluated by determining minimum inhibitory concentration (MIC), minimum bactericidal concentration, and antibiogram test.Results: The MIC for essential oil of Z. tenuior was 250mg/mL for most Gramnegative bacteria exceptPseudomonas aeruginosa. Moreover, the MIC for Staphylococcus aureuswas 250mg/mL and 500mg/mL for other strains of Staphylococcus.Conclusion: Comparison of the inhibitory and bactericidal effects of the essential oil and methanol extract ofZ. tenuior showed that the essential oil is able to inhibit growth of the bacteria tested even in low concentrations. Further studies are required in this regard using animal models.