ABSTRACT
Bacterial meningitis is one of the most severe infectious diseases with high rate of morbidity and mortality in developing countries. The current study aimed to investigate the frequency of etiological agents of bacterial meningitis among patients admitted to three hospitals in Zanjan, Iran. A total of 100 cerebrospinal fluid (CSF) samples were collected aseptically, and cytochemical analysis, Gram staining, culture, and PCR were performed. Forty-six percent of CSF samples had positive bacterial culture results. However, PCR showed a higher detection rate of bacterial meningitis causing pathogens when compared with culture (52% vs. 46%; p > 0.05). Fifty-two percent of patients with bacterial meningitis were aged <1 year. The most prevalent pathogen was Streptococcus pneumoniae (36.5%), followed by Neisseria meningitidis (28.8%) and Streptococcus agalactiae (15.4%). Listeria monocytogenes was not isolated from CSF culture. The frequency of Haemophilus influenzae, L. monocytogenes and Escherichia coli was 7.7%, 1.9% and 9.6%, respectively. Although in patients aged <1 year, S. pneumonia, N. meningitidis and group B streptococcus were the most common pathogens causing meningitis, and in patients aged between 1 and 10 years, Escherichia coli was the most common. According to the results, the culture was less effective for diagnosis of bacterial meningitis than PCR. Our findings indicate that the most common causative agents of bacterial meningitis in Iran may be vaccine-preventable pathogens. Therefore, the prevention and control measures should be considered to reduce the incidence of bacterial meningitis.
ABSTRACT
Subinhibitory concentrations (subMIC) of antibiotics, although not able to kill bacteria, can modify their physicochemical characteristics and may interfere with some bacterial functions. This study aimed to investigate the effect of subMIC of imipenem and piperacillin on the transcriptional expression of virulence-related genes toxA and exoS in Pseudomonas auroginosa. Five clinical isolates of P. aeruginosa were screened for the presence of toxA and exoS genes and MICs of imipenem and piperacillin were determined using broth macrodilution. The expression levels of toxA and exoS at subMIC concentrations of antibiotics were measured by real-time PCR. Our results showed that the expression of toxA decreased at all subinhibitory concentrations of imipenem, especially at concentrations 2, 4 and 8 mg/L (p < 0.05). Whereas, exoS expression was increased 4.1- to 7-fold at subinhibitory concentrations of imipenem. The increase of toxA expression was measured at concentrations 16, 4, 2, 0.25 and 0.125 mg/L of piperacillin. However, piperacillin had no significant influence on exoS expression (p > 0.05). Further studies will be required to assess whether subMIC of imipenem can improve the outcomes of severe and serious infections caused by P. aeruginosa.
ABSTRACT
Whole-cell pertussis vaccine (wP) has been imperative and highly effective in preventing childhood deaths due to pertussis. Pertussis toxin is one of the virulence factors of Bordetella pertussis in all available pertussis vaccines. wP production in Razi Vaccine and Serum Research Institute is according to bioreactor culture of B. pertussis strains in B2 medium. The aim of this study was to evaluate B. pertussis strain 509 PT production in B2 and Thalen-IJssel (THIJS) media by Chinese Hamster Ovary (CHO) cell and enzyme-linked immunosorbent assay methods (ELISA). In the current study, B. pertussis strain 509 was cultured in B2 and THIJS media. Six samples were taken during the log growth phase within 2-3 h intervals (triplicate). The growth rate was calculated using opacity and the quantification of cell-associated and released PT measured by ELISA and CHO cell assays. THIJS medium was significantly showed an increase in the bacterial growth rate. During the first 29 h, bacterial concentrations in B2 and THIJS culture medium were 19 and 29 IOU, respectively. In THIJS medium, greater amount of pertussistoxin production was cell-associated. In B2 medium, maximum cell-associated toxin by ELISA and CHO cell assays were in the ODs of 1.1 and 0.9 and for THIJS medium in the ODs of 1.6 and 1.1, respectively. B. pertussis strain 509 in THIJS medium produced higher cell mass and cell-associated pertussis toxin than that of B2. It can be used for the production of whole-cell vaccine with higher pertussis toxin and accordingly using lower biomass per dose leading to the reduction of vaccine toxicity.
Subject(s)
Bordetella pertussis/physiology , Pertussis Toxin/physiology , Pertussis Vaccine/chemistry , Animals , CHO Cells , Cricetulus , Culture Media , Enzyme-Linked Immunosorbent AssayABSTRACT
BACKGROUND & OBJECTIVES: This paper presents the results of a study on ecological parameters including diversity indices applied on populations of Culicidae mosquitoes (Diptera: Culicidae) from three rural areas (Darvishan, Chalmardi and Khairabad) of Neka township in Mazandaran province, northern Iran. METHODS: Adult and larval stages of mosquitoes were systematically sampled to obtain data required for measuring diversity of mosquitoes in these areas. Alfa and beta indices were analyzed to compare mosquito diversity. A total of 5270 specimens belonging to four genera and 14 different species were collected and identified. RESULTS: Evaluation of dominance structure of species showed that culicid mosquitoes of Neka rangelands include one eudominant species, two dominant species, two subdominant species, two rare species and eight subrare species when Heydemann classification was used. INTERPRETATION & CONCLUSION: Data analysis revealed a higher diversity of mosquitoes in Khairabad with a low degree of interspecific dominance, while Darvishan and Chalmardi recorded the lowest observed diversity and a high degree of interspecific dominance. The cluster analysis based on Jaccard's index indicated the relationship between the categories and indicates that Darvishan and Khairabad are the closest categories in their specific composition.
