[Production of Braxy vaccine by fermenter and enriched culture media]

Braxy vaccine, a culture of a suitable strain or strains of Clostridium septicum in a fluid medium, its filtrate or derivatives, will be inactivated so that it produces its immunogenic activity without toxicity. Production of C. septicum vaccine [Braxy vaccine] using enriched culture media in fermenter. Conventional and enriched culture media were used for growing C. septicum [CN913] vaccinal strain in both 10 liter glass bottle and fermenter, in a triplicate manner. All twelve experiments were inspected to ensure compliance with the requirements of the vaccine international standards for minimum lethal dose [MLD], sterility, freedom of abnormal toxicity, safety and potency tests. Results showed that the culture of C. septicum in fermenter using enriched culture media is the best. Based on international standards, 2.5IU/mL was determined for C. septicum alpha toxin potency test, but in this study 4IU/mL was obtained. Using enriched culture media in fermenter is suitable for braxy vaccine production

[Clostridium perfringens type a related enteritis: a case report in dogs]

On June 2010, in Tehran province 7 out of 82 dogs in a kennel, showed clinical signs of enteritis which resulted in death [n=5]. Clinical findings were diarrhea, dysentery, fever, depression, neural sings and sudden death. Necropsy findings revealed hemorrhagic enteritis, catarrhal gasteritis, multifocal necrosis up to 0.5 cm in diameter in cerebral cortex with hyperemia and hemorrhage. Necropsy was done on 4 cases and intestinal contentes were cultured to characterize Clostridium perfringens type using PCR. Rapid test antibody for parvovirus and distemper virus showed that 2 out of 4 puppies were positive against distemper virus. According to nonsuppurative encephalitis, gliosis, intranuclear inclusion bodies in astrocytes, packed cell volume, interstitial pneumonia and positive reaction to distemper virus it can be concluded that primary distemper disease has been followed by, hemorrhagic enteritis and diarrhea as a secondary infection to Clostridium perfringens type A

Bacteriological and serological studies on mannheimia haemolytica infection in cattle slaughtered at Ahvaz [southwestern Iran] abattoir

In order to investigate the prevalence of Mannheimia haemolytica infection in cattle, nasal and nasopharyngeal swabs and blood samples were obtained from 250 cattle after slaughter at Ahvaz [southwestern Iran] abattoir. Nasal and nasopharyngeal swabs were cultured on blood agar and incubated at 37 [degree sign] C for 24-48 h. The suspected bacterial cultures were processed for isolation of M. haemolytica following routine bacteriological techniques. Sera were tested by indirect hemagglutination test [IHA] to reveal antibodies against the organism. M. haemolytica was isolated from 1.6% of the samples cattle. Statistical analysis showed that there was no relationship between age and sex with bacterial infection. Serological studies showed that 71.6% of tested sera contained antibody [titer >/= 1/16] against M. haemolytica. There was no association between age and sex with serological results

Genetic variations of avian Pasteurella multocida as demonstrated by 16S-23S rRNA gene sequences comparison

Pasteurella multocida is known as an important heterogenic bacterial agent causes some severe diseases such as fowl cholera in poultry and haemorrhagic septicaemia in cattle and buffalo. A polymerase chain reaction [PCR] assay was developed using primers derived from conserved part of 16S-23S rRNA gene. The PCR amplified a fragment size of 0.7 kb using DNA from nine avian P. multocida isolates. Sequence alignment of the 16S-23S rRNA genes [ITS] revealed a considerable heterogenicity among the isolates. The percentage of similarity varied from 83.3 to 100% among the isolates. An interesting finding from this study was the presence of an inserted sequence [seven nucleotides] in the 16S-23S rRNA region in 55% of the isolates. According to phylogenic analysis based on ITS sequence alignment, the P. multocida isolates classified into 2 distinct clusters. The virulence of isolates in cluster II were higher than those in cluster I. Ribotyping of P. multocida by using 16S-23S rRNA gene PCR sequencing could be used as a marker in epidemiologic studies

Pathogenicity and immunogenicity of native and mutant strains of Pasteurella multocida, the causative agents of haemorrhagic septicaemia

Haemorrhagic septicaemia [HS] is a fatal systemic disease of cattle and buffaloes. Some control is achieved with administration of alum-precipitated or oil-adjuvanted killed whole-cell vaccines injected subcutaneously. These vaccines, however, provide only short-term immunity and for effective use, they should be administered annually. We constructed an aroA attenuated derivative of a Pasteurella multocida serotype B:2 strain by allelic exchange of the native aroA sequence with aroA sequences disrupted with a kanamycin resistance cassette. This strain was confirmed to be aroA mutant by PCR. The aroA derivative was highly attenuated for virulence in a mouse model of HS and rabbits. Mouse and rabbit challenge experiments showed that i.p. or i.m. vaccination of an aroA strain completely protected mice or rabbits against challenge with a high dose [>1000 LD[50]] of the parent strain

Measuring of free endotoxin in alum-precipitated vaccine of haemorrhagic septicaemia by limulus amebocyte lysate test

Haemorrhagic septicaemia [HS] vaccine which is prepared in Razi Institute is used in endemic areas of Iran. Aluminum-hydroxide gel was used as adjuvant for preparing this vaccine. Post-vaccinal shock reactions were the main complaint after use of this vaccine. In a previous study, we could improve the vaccine by alum-precipitation Pasteurella multocida cells and removing the liquid phase. In this study, the amount of free endotoxin in aluminum-hydroxide and alum-HS vaccines was determined. It was found that endotoxin level was considerably decreased from 0.22 EU/ml to 0.03 EU/ml after alum-precipitation

Polymerase chain reaction typing of Pasteurella multocida capsules isolated in Iran

Capsules from a range of pathogenic bacteria are the key determinants of virulency. The capsule has been implicated in virulence of Pasteur'ella multocida. In this study a type-specific polymerase chain reaction [PCR] assay was used for capsular typing of 39 avian P. multocida isolates from Iran. The PCR amplified a fragment of 1044 bp from all of tested isolates. It was found that all avian P. multocida isolates belonged to capsular type A. The sequence alignment of the fragment showed a high similarity [>96%] with the published sequences of P. multocida hya gene in the Gene Bank. It was recognised that P. multocida capsular group A is the dominant cause of fowl cholera in Iran