Chauhan Nutan, Kumar Sachin, Chauhan Tejshi, Samanta Ashis Kumar
Rumen Biotechnology Lab, Animal Nutrition Division, ICAR-National Dairy Research Institute, Karnal, Haryana, 132001, India.
Int Microbiol. 2024 Dec 11. doi: 10.1007/s10123-024-00623-6.
Antibiotic therapy has been the most popular line of treatment for the control of mastitis worldwide during the last few decades. Alternative and sustainable treatments must be developed because pathogens are becoming more resistant to antibiotics, leading to the development and spread of antimicrobial resistance (AMR). The aim of the current investigation was to isolate lactic acid bacteria (LAB) with probiotic potential that can inhibit mastitis-causing pathogens to prevent bovine mastitis. Milk samples were collected from Sahiwal cows, and a total of 150 bacteria were isolated, of which 76 were found to be catalase negative, and resistant to vancomycin. Twenty-three isolates displayed greater acid and bile tolerance, with > 90% survivability, and were molecularly characterized by 16S rRNA partial sequencing. The autoaggregation percentages for SML7 and SML41 were greater (p<0·05) 80.38±0.19% and 80.28±0.04%, respectively. SML10 (92.04±0.26 μmol/mL) had the highest (p<0.05) ferric-reducing antioxidant power (FRAP) activity, while SML20 (52.1±0.99%) had the highest 1,1 diphenyl 2 picrylhydrazyl (DPPH) scavenging activity. All the strains were nonhemolytic or nonmucinolytic. The highest antimicrobial activity was observed in several strains (SML41, SML63, SML76, and SML60) against common mastitis-causing pathogens, namely, E. coli ATCC25922, Staphylococcus aureus ATCC25923, Enterococcus faecalis NCDC114, Streptococcus agalactiae NCDC208, and Enterococcus faecium NCDC124. The coaggregation efficacy of SML20 with S. aureus was the highest (67.69±1.21%), while SML41 showed the highest (69.75±0.29%) coaggregation efficacy with E. faecalis NCDC114 and SML63 (68.078±0.26) with S. agalactiae NCDC208. Overall, seven distinct lactic acid bacterial clusters were identified by cluster analysis of the phylogenetic tree as follows: Enterococcus hirae (1), Limosilactobacillus reuteri (1), Pediococcus acidilactici (4), Weissella confusa (11), Lactobacillus helveticus (3), Limosilactobacillus balticus (2), and Lacticaseibacillus rhamnosus (1). The Lactobacillus helveticus SML41, Lactobacillus helveticus SML60, Weissella confusa SML61, Lacticaseibacillus rhamnosus SML63, Weissella confusa SML64, and Pediococcus acidilactici SML76 isolates were found to possess the most desirable characteristics of potential probiotics based on principal component analysis (PCA). Therefore, the strains chosen in the current investigation demonstrated techno-functional characteristics that rendered them appropriate for probiotic use to treat and prevent intramammary infections in dairy cattle in a sustainable manner.
在过去几十年里，抗生素疗法一直是全球控制乳腺炎最常用的治疗方法。由于病原体对抗生素的耐药性越来越强，导致抗菌药物耐药性（AMR）的产生和传播，因此必须开发替代的可持续治疗方法。当前研究的目的是分离具有益生菌潜力的乳酸菌（LAB），这些乳酸菌能够抑制引起乳腺炎的病原体，从而预防奶牛乳腺炎。从萨希瓦尔奶牛采集牛奶样本，共分离出150株细菌，其中76株过氧化氢酶阴性，对万古霉素耐药。23株分离菌表现出更强的耐酸和耐胆汁能力，存活率>90%，并通过16S rRNA部分测序进行分子鉴定。SML7和SML41的自聚集百分比更高（p<0·05），分别为80.38±0.19%和80.28±0.04%。SML10（92.04±0.26μmol/mL）具有最高（p<0.05）的铁还原抗氧化能力（FRAP）活性，而SML20（52.1±0.99%）具有最高的1,1-二苯基-2-苦基肼（DPPH）清除活性。所有菌株均无溶血或解粘蛋白活性。在几种菌株（SML41、SML63、SML76和SML60）中观察到对常见乳腺炎病原体，即大肠杆菌ATCC25922、金黄色葡萄球菌ATCC25923、粪肠球菌NCDC114、无乳链球菌NCDC208和屎肠球菌NCDC124的最高抗菌活性。SML20与金黄色葡萄球菌的共聚集效率最高（67.69±1.21%），而SML41与粪肠球菌NCDC114的共聚集效率最高（69.75±0.29%），SML63与无乳链球菌NCDC208的共聚集效率最高（68.078±0.26）。总体而言，通过系统发育树的聚类分析确定了七个不同的乳酸菌簇，如下所示：希氏肠球菌（1株）、罗伊氏乳杆菌（1株）、嗜酸乳杆菌（4株）、混淆魏斯氏菌（11株）、瑞士乳杆菌（3株）、波罗的海乳杆菌（2株）和鼠李糖乳杆菌（1株）。基于主成分分析（PCA），发现瑞士乳杆菌SML41、瑞士乳杆菌SML60、混淆魏斯氏菌SML61、鼠李糖乳杆菌SML63、混淆魏斯氏菌SML64和嗜酸乳杆菌SML76分离株具有潜在益生菌最理想的特性。因此，本研究中选择的菌株表现出技术功能特性，使其适合以可持续的方式用于治疗和预防奶牛乳房内感染的益生菌。
