Adib N, Zahmatkesh A, Esmaeilnejad-Ahranjani P, Paradise A, Abdolmohammadi Khiav L, Bagheri M, Abdoli M, Adib A. Effect of formalin percentage, incubation time and temperature on Clostridium chauvoei culture inactivation and immunogenicity.
Anaerobe 2023;
83:102781. [PMID:
37660749 DOI:
10.1016/j.anaerobe.2023.102781]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 08/05/2023] [Accepted: 08/12/2023] [Indexed: 09/05/2023]
Abstract
OBJECTIVES
In order to find the optimal inactivation conditions for Clostridium chauvoei culture, different factors were investigated and the immunogenicity of inactivated cultures was studied.
METHODS
C. chauvoei was cultured with different formalin percentages (0.3, 0.5 or 0.7% V/V), inactivation temperatures (37 °C or room temperature) and incubation times (one or two weeks). Sterility tests were performed and residual formaldehyde and pH were measured. Rabbits were immunized twice with inactivated cultures and sera were used for detection of immune response.
RESULTS
In the one-week experiment, 0.5 and 0.7% formalin inactivated the bacteria after one week, and the percentage of 0.3 inactivated after three weeks. The residual formaldehyde at weeks 1 and 8 was not significantly different. In the two-week experiment, cultures treated with 0.3 and 0.5% formalin were inactivated after four weeks, and those with 0.7% formalin were inactivated after three weeks. Residual formaldehyde at week 8 differed significantly from that of week 1. Residual formaldehyde was affected by incubation temperature since it was lower at 37 °C than in room temperature. Also, a significant effect was observed for formalin on pH, as higher formalin contents led to lower pH values of the cultures. ELISA showed the lowest antibody titer achieved by 0.7% formalin group. Antibody titer was not different between 0.3 and 0.5% formalin.
CONCLUSIONS
The best condition for inactivation of C. chauvoei was considered as one-week incubation with 0.5% formalin at 37 °C, leading to a high antibody response.
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