Isolation of the various serotypes of Mannheimia haemolytica and preparation of the first vaccine candidate in Iran.

BACKGROUND: Mannheimia haemolytica is one of the main agents of domestic pneumonic mannheimiosis, but a proper vaccine has not been explored in IRAN. METHODS AND RESULTS: 362 lung and nasal samples from sick domestic animal were detected by culture and PCR methods. Totally, 71 M. haemolytica isolates were identified in three main serotypes (A1, A2, and A6). Serotypes A2 (38/71; 54%) and A1 (25/71; 39%) were the most frequently detected, whereas the A6 serotype was detected with a frequency of less than 1% (1/71; 1%) and 7 isolates remained unknown (7/71; 10%). Subsequently, M. haemolytica vaccinal strain was developed and then formalin-killed vaccine was prepared. It provided the best protection against mannheimiosis in sheep which was proved by indirect ELISA. CONCLUSIONS: Our results suggest that the efficacy and safety of vaccine strain are remarkable and may serve as a new therapeutic target in mannheimiosis.

Growth and replication of infectious bursal disease virus in the fish cell line as an experimental vaccine.

Recently, several attempts have been made to replace egg-based with cell-based vaccines to prevent and control Infectious Bursal Disease Virus (IBDV). This study aimed to evaluate a new fish cell line (M99) for culturing and replicating IBDV. After observing complete cytopathic effects (CPE) on the M99 cell line, virus titers were determined using the TCID50 test, and the presence of the virus was confirmed using an RT-PCR test. Subsequently, 135 broiler chickens (14 days old) were randomly divided into three equal groups for immune response measurements: G1: immunized with a commercial vaccine, G2: immunized with an experimental vaccine, and G3: control. Antibody responses, bursal index, and histopathological evaluations were examined on different days after immunization. Based on the results, CPE of the virus was noticeable from the first passage, becoming complete by the third passage. The infectious titer of the virus was log106.9. Antibody titer measured 21 days after immunization in both vaccinated groups were significantly differed from the control group (p < 0.05). The results obtained from examining the bursal index and histopathological evaluations showed no significant difference between the studied groups at different times. Overall, this research is the first report on the successful cultivation of infectious bursal virus on a permanent cell line of fish origin, with the advantages of tolerance to a wide temperature range (26-40 degrees Celsius). Therefore, this cell line has potential for use to attenuate, cultivate, and adapt other pathogens to cold temperatures in future studies.

Prevalence of Helicobacter pylori infection in children (south of Iran).

The prevalence of Helicobacter pylori in children ranges from 10% to more than 80%. High prevalence occurs in developing countries, and after colonization it takes an extended period to be eradicated by the immune system. To evaluate the prevalence and age distribution of H. pylori infection in children in Shiraz (a city in the south of Iran), we collected 593 stool samples from children selected randomly from 5 age groups. Infection was determined based on antigen immunoassay in stool using the enzyme-linked immunosorbent assay method. The prevalence rates were 82%, 98%, 88%, 89%, and 57% in age groups of 9 months, and 2, 6, 10, and 15 years, respectively. There were no significant differences between the prevalence of H. pylori infection in the first 4 age groups (P > 0.05), but there was a significant decrease in the 15-year-old group (P < 0.05). The prevalence of H. pylori infection in the south of Iran is very high. The infection begins at infancy and remains high until late childhood.

Immunodominant antigens of Helicobacter pylori strains isolated from patients with different gastroduodenal diseases.

OBJECTIVE: To detect the immunogenic proteins in Helicobacter pylori (H. pylori) strains isolated from patients with different gastric diseases. METHODS: We performed this study in the Clinical Microbiology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran, during July 2003 to September 2004. Total proteins of H. pylori strains isolated from the gastric biopsies of 3 groups of patients were separated by 1D-SDS-PAGE and then blotted with the sera of their respective hosts. RESULTS: In SDS-PAGE the members of each group showed high correlation according to similarity in their patterns, resulting in considering them in the same cluster. The patterns of immunoblots differed from that of Coomassie Brilliant Blue stained gels. The blotting method did not recognize some of the protein bands in the SDS-PAGE. Only the bands of 106 and 45 kDa from H. pylori strains isolated from patients with gastric cancer were significantly (p<0.05) recognized specifically with the sera of their respective patients, and the band of 13 kDa was recognized specifically (p<0.05) with the sera of nonulceric patients. With the exception of these bands, in the patterns of blotting of the sera from all patients no significant differences were observed. CONCLUSION: By using 1D blotting methods we could find 2 antigenic protein bands (106 and 45 kDa) for H. pylori strains isolated from cancerous patients, and one (13 kDa) for the strains isolated from nonulceric patients, which were specifically recognized with their respective host.

Detection of enterotoxigenic K99 (F5) and F41 from fecal sample of calves by molecular and serological methods.

Enterotoxigenic Escherichia coli (ETEC) is one of the major causes of neonatal calf diarrhea. Almost all ETEC bacteria are known to adhere to receptors on the small intestinal epithelium via their fimbriae, (F5 (K99) and F41).This study was undertaken to investigate the phenotypic and genotypic screening of virulence genes in E. coli K99 and F41. During January 2008 to December 2009, 298 diarrheic neonatal calves at 1-30 days old were studied by multiplex PCR, isolation, and serological grouping. Of the 298 diarrheic samples, 268 E. coli were isolated, of which 16 samples (5.3%) were positive for having the F5 (K99) fimbrial gene by PCR while all of the E. coli isolates also carried F41 fimbrial genes. Twenty-five percent of the isolates were proven not to be toxigenic as they did not possess the STa enterotoxin gene.