The most clinically relevant staphylococci in veterinary medicine are those that are coagulase-positive, namely Staphylococcus aureus. During microbiological udder health monitoring (2009–2018), a new S. aureus strain (coagulase-positive and maltose-negative) was discovered as an emerging udder pathogen during routine examinations of South African dairy herds. This study challenged the conventional microbiological diagnosis of staphylococci by comparing its results to those of the MALDI-TOF mass spectrometry and 16S rRNA sequencing. Both of these tests confirmed that the maltose-negative staphylococcus (MNS), identified as Staphylococcus pseudintermedius by conventional microbiology, was S. aureus ST2992. Multi locus sequence typing was performed on 3 of the MNS isolates and indicated that these isolates were of single origin. These strains tested positive for both MALA and MALR genes (control: S. aureus ATCC 25923). Although the α-glucosidase gene was present, it was not expressed phenotypically. The latter may be attributed to the abnormal stop codon identified in the MALA gene sequence of S. aureus ST2992 (GenBank accession number, MN531305). The newly identified MNS has a field behavior different to that of maltose-positive S. aureus, and more similar to the low virulence of non-aureus staphylococci.

兽药中临床上最相关的葡萄球菌是凝固酶阳性的葡萄球菌，即金黄色葡萄球菌。在微生物乳房健康监测（2009- 2018年）期间，在南非奶牛场常规检查中，发现了一种新的金黄色葡萄球菌（凝固酶阳性和麦芽糖阴性）作为新兴的乳房病原体。通过将其结果与MALDI-TOF质谱和16S rRNA测序结果进行比较，这项研究对葡萄球菌的常规微生物学诊断提出了挑战。这两项测试均证实，由常规微生物学鉴定为麦芽糖阴性葡萄球菌（MNS）的是金黄色葡萄球菌。ST2992。对3个MNS分离株进行了多基因座序列分型，表明这些分离株是单一起源的。这些菌株对MALA和MALR基因测试均为阳性（对照：金黄色葡萄球菌ATCC 25923）。尽管存在α-葡糖苷酶基因，但它不是表型表达的。后者可归因于在金黄色葡萄球菌ST2992的MALA基因序列（GenBank登录号，MN531305）中鉴定的异常终止密码子。新近鉴定的MNS具有不同于麦芽糖阳性金黄色葡萄球菌的田间行为，并且更类似于非金黄色葡萄球菌的低毒力。