Porto Conte Ricerche,Alghero,Italy.
Dipartimento di Medicina Veterinaria,Università degli Studi di Milano,Milan,Italy.
J Dairy Res. 2019 May;86(2):217-221. doi: 10.1017/S0022029919000335. Epub 2019 Jun 3.
This research communication reports the evaluation of cathelicidin in dairy goat milk for its relationship with the somatic cell count (SCC) and microbial culture results. Considering the limited performances of SCC for mastitis monitoring in goats, there is interest in evaluating alternative diagnostic tools. Cathelicidin is an antimicrobial protein involved in innate immunity of the mammary gland. In this work, half-udder milk was sampled bimonthly from a herd of 37 Alpine goats along an entire lactation and tested with the cathelicidin ELISA together with SCC and bacterial culture. Cathelicidin and SCC showed a strong correlation (r = 0.72; n = 360 milk samples). This was highest in mid-lactation (r = 0.83) and lowest in late lactation (r = 0.61), and was higher in primiparous (0.80, n = 130) than in multiparous goats (0.71, n = 230). Both markers increased with stage of lactation, but cathelicidin increased significantly less than SCC. In addition, peak level in late lactation was lower for cathelicidin (5.05-fold increase) than for SCC (7.64-fold increase). Twenty-one (5.8%) samples were positive to bacteriological culture, 20 for coagulase-negative staphylococci and one for Streptococcus spp.; 18 of them were positive to the cathelicidin ELISA (85.71% sensitivity). Sensitivity of SCC >500 000 and of SCC >1 000 000 cells/ml was lower (71.43 and 23.81%, respectively). Therefore, the high correlation of cathelicidin with SCC during the entire lactation, along with its lower increase in late lactation and good sensitivity in detecting intramammary infection (IMI), indicate a potential for monitoring subclinical mastitis in dairy goats. However, based on this preliminary assessment, specificity should be improved (40.41% for cathelicidin vs. 54.57 and 67.85% for SCC >500 000 and >1 000 000 cells/ml, respectively). Therefore, the application of cathelicidin for detecting goat IMI will require further investigation and optimization, especially concerning the definition of diagnostic thresholds.
本研究通讯报告了乳用山羊乳中抗菌肽的评估，以研究其与体细胞计数 (SCC) 和微生物培养结果的关系。鉴于 SCC 对山羊乳腺炎监测的有限性能，人们有兴趣评估替代诊断工具。抗菌肽是一种参与乳腺先天免疫的抗菌蛋白。在这项工作中，从一个 37 只高山奶山羊的畜群中每隔两个月采集半乳样，并与 SCC 和细菌培养一起使用抗菌肽 ELISA 进行检测。抗菌肽和 SCC 呈强相关性 (r = 0.72; n = 360 个乳样)。在泌乳中期相关性最高 (r = 0.83)，泌乳后期最低 (r = 0.61)，初产羊高于经产羊 (0.80，n = 130 比 0.71，n = 230)。两种标志物均随泌乳阶段而增加，但抗菌肽的增加显著低于 SCC。此外，泌乳后期抗菌肽的峰值水平较低 (5.05 倍增加) 低于 SCC (7.64 倍增加)。21 份 (5.8%) 样本的细菌培养呈阳性，20 份为凝固酶阴性葡萄球菌，1 份为链球菌属；其中 18 份对抗菌肽 ELISA 呈阳性 (85.71% 的敏感性)。SCC >500 000 和 SCC >1 000 000 细胞/ml 的敏感性较低 (分别为 71.43% 和 23.81%)。因此，在整个泌乳期，抗菌肽与 SCC 高度相关，泌乳后期增加较少，对检测乳腺炎感染 (IMI) 的敏感性较好，表明其具有监测乳用山羊亚临床乳腺炎的潜力。然而，基于这一初步评估，特异性应得到提高 (抗菌肽为 40.41%，SCC >500 000 和 SCC >1 000 000 细胞/ml 分别为 54.57% 和 67.85%)。因此，抗菌肽用于检测山羊 IMI 的应用需要进一步研究和优化，特别是在诊断阈值的定义方面。
