Distribution of coagulase-negative Staphylococcus species from milk and environment of dairy cows differs between herds

Abstract

In many parts of the world, coagulase-negative staphylococci (CNS) are the predominant pathogens causing intramammary infections (IMI) in dairy cows. The cows' environment is thought to be a possible source for CNS mastitis and this was investigated in the present paper. A longitudinal field study was carried out in 6 well-managed dairy herds to determine the distribution and epidemiology of various CNS species isolated from milk, causing IMI and living freely in the cows' environment, respectively. In each herd, quarter milk samples from a cohort of 10 lactating cows and environmental samples from stall air, slatted floor, sawdust from cubicles, and sawdust stock were collected monthly (n=13). Isolates from quarter milk samples (n=134) and the environment (n=637) were identified to species level using amplified fragment length polymorphism (AFLP) genotyping. Staphylococcus chromogenes, S. haemolyticus, S. epidermidis, and S. simulans accounted for 81.3% of all CNS milk isolates. Quarters were considered infected with CNS (positive IMI status) only when 2 out of 3 consecutive milk samples yielded the same CNS AFLP type. The species causing IMI were S. chromogenes (n=35 samples with positive IMI status), S. haemolyticus (n=29), S. simulans (n=14), and S. epidermidis (n=6). The observed persistent IMI cases (n=17) had a mean duration of 149.4 d (range 63.0 to 329.8 d). The CNS species predominating in the environment were S. equorum, S. sciuri, S. haemolyticus, and S. fleurettii. Herd-to-herd differences in distribution of CNS species were observed in both milk and the environment, suggesting that herd-level factors are involved in the establishment of particular species in a dairy herd. Primary reservoirs of the species causing IMI varied. Staphylococcus chromogenes and S. epidermidis were rarely found in the environment, indicating that other reservoirs were more important in their epidemiology. For S. haemolyticus and S. simulans, the environment was found as a reservoir, suggesting that IMI with these species were possibly environmental in origin.

Quarter- and cow-level risk factors for intramammary infection with coagulase-negative staphylococci species in Swiss dairy cows

“…simulans, and Staph. xylosus were considered the most important CNS species causing IMI (Vanderhaeghen et al, 2015), but patterns of CNS species are frequently herd specific (Piessens et al, 2011;Supré et al, 2011). Within our study herds, a herd-specific pattern was particularly pronounced for the Staph.…”

“…chromogenes was mainly present in milk samples, whereas Staph. haemolyticus was more often identified in samples collected from the cow's environment (Piessens et al, 2011), partly explaining herd specific species distribution. However, only 3 herds were included in the present study and therefore results need to be interpreted and compared with care.…”

“…xylosus, the months June to November and June to August, respectively, were associated with higher odds for IMI, similar to the results of De Visscher et al (2017) who found an increased risk for presence of more relevant species in bulk tank milk in June and September. Because both species are frequently found in the cow's environment (Matos et al, 1991;Piessens et al, 2011), these associations might be caused by a high environmental bacterial pressure caused by warm weather conditions in summer and early autumn. In contrast, the months from September to February were associated with higher odds for Staph.…”

Detection and Characteristics of Coagulase-Negative Staphylococcus sp. isolated from Dairy Cattle Milk

“…원인균으로 세계적으로 분리되는 빈도가 증가하고 있다 (Sawant et al, 2009;Piessens et al, 2011). Staphylococci는 혈액 응고를 일으키는 효소인 coagulase를 생산하는 능력에 기초하여 Coagulase-positive Staphylococci(CPS)와 CNS로 나누어진다.…”

“…유방염 진단에서 S. aureus는 주요 병원균으로 잘 알려져 있지만, CNS는 보통 준임상적 또는 경증의 유방염만을 일으키기 때문에 종 수준으 로 식별되지 않고 하나의 그룹으로 취급하였다 (Pyörälä and Taponen, 2009a). 그러나 최근 연구에 따르면 일부 종은 임상적 유방 염과 관련성이 있을 수 있다고 지적하고 있다 (Piessens et al, 2011). 또한 CNS는 많은 국가에서 유방염을 일으키는 가장 흔한 원 인체가 되었고, 유선에 상재하면서 체세포 수를 증가시키고, 우유의 품질저하를 유발한다 (Nam et al, 2012).…”