Sophorn Nouv, Sambo Na, Ohkura Satoshi, Nakamura Sho, Matsuyama Shuichi, Murase Tetsuma, Soriya Rin, Suriyasathaporn Witaya
Asian Satellite Campuses Institute, Nagoya University, Nagoya, Japan.
Department of Animal Health and Veterinary Public Health, General Directorate of Animal Health and Production, Phnom Penh, Cambodia.
Transbound Emerg Dis. 2025 Mar 3;2025:3621605. doi: 10.1155/tbed/3621605. eCollection 2025.
The complete mastitis control program is insufficient for the starting dairy industry country, and therefore it might cause emerging of new mastitis pathogens. This longitudinal study aimed to determine the association of the infected dynamic status of the main pathogens responsible for mastitis with seasonal variations, the proportions of transient and chronic intramammary infection (IMI) episodes, and the duration of IMI. This study was conducted on a training smallholder dairy farm in Phnom Penh, Cambodia, from January 2023 to July 2023. Trained veterinarians aseptically collected quarter milk samples from all milking cows ( = 21) every 2 weeks until the end of the study, accounting for 3-16 times of milk collection per cow based on their period of lactation. All collected milk samples ( = 812) were cultured, and subsequently, all bacterial colonies were identified using a MALDI-TOF mass spectrometer. An IMI episode is defined as a sequence of consecutive isolates of a specific bacterium from the same quarter. The duration of an episode is the time between the new IMI and its cure. Two types of IMI were defined as transient IMI and chronic IMI that lasted for 28 days or more. Results of the IMI episodes, distributions of no, single, double-mixed, and 3-mixed IMI were 61.1%, 31.9%, 6.3%, and 0.7%, respectively, in which the mixed IMI accounts for 18% of IMI samples. , , and were the main organisms responsible for the mastitis epidemic on this farm. These bacteria had higher ratios of chronic episodes than the other mastitis bacteria found on this farm. In addition, results obtained from Cox's model showed that had a longer time to cure than pathogens other than and , in which linked to colon neoplasia in humans. In conclusion, the lack of an optimal mastitis control program, in this case, provides information on the emerging mixed infections, emerging mastitis pathogens, and emerging chronic infections.
完整的乳腺炎防控计划对于起步阶段的乳业国家来说并不充分，因此可能会导致新的乳腺炎病原体出现。这项纵向研究旨在确定导致乳腺炎的主要病原体的感染动态状况与季节变化、短暂性和慢性乳房内感染（IMI）发作比例以及IMI持续时间之间的关联。本研究于2023年1月至2023年7月在柬埔寨金边的一个培训型小农户奶牛场进行。训练有素的兽医每2周从所有挤奶牛（n = 21头）的每个乳区无菌采集牛奶样本，直至研究结束，根据奶牛的泌乳期，每头奶牛采集3至16次牛奶样本。对所有采集的牛奶样本（n = 812份）进行培养，随后使用基质辅助激光解吸电离飞行时间质谱仪鉴定所有细菌菌落。IMI发作定义为从同一乳区连续分离出特定细菌的序列。发作持续时间是新的IMI与其治愈之间的时间。两种类型的IMI被定义为短暂性IMI和持续28天或更长时间的慢性IMI。IMI发作结果显示，无感染、单一感染、双重混合感染和三重混合感染的分布分别为61.1%、31.9%、6.3%和0.7%，其中混合IMI占IMI样本的18%。金黄色葡萄球菌、无乳链球菌和停乳链球菌是该农场乳腺炎流行的主要病原体。与该农场发现的其他乳腺炎细菌相比，这些细菌的慢性发作比例更高。此外，Cox模型的结果显示，金黄色葡萄球菌的治愈时间比金黄色葡萄球菌和停乳链球菌以外的病原体更长，其中金黄色葡萄球菌与人类结肠癌有关。总之，在这种情况下，缺乏最佳的乳腺炎防控计划提供了有关新出现的混合感染、新出现的乳腺炎病原体和新出现的慢性感染的信息。
