title: Characteristics of Staphylococcus aureus small colony variant and its parent strain isolated from chronic mastitis at a dairy farm in Beijing, China.
abstract: Staphylococcus aureus is a major pathogen associated to bovine mastitis and has the ability to form a slow-growing population termed the small colony variants (SCVs). From 20 samples of 5 chronic S. aureus cases, 1 SCV isolate (SCV102) was recovered simultaneously with 1 of 8 S. aureus isolates. SCV102 showed auxotrophy for thymidine and had a slow growth rate. Intracellular persistence in human mammary epithelial cells (HBL100cell line) monolayer revealed that SCV102 isolate had minimal cytopathological effects compared with its parent strains. SCV102 isolate and its parent strain S. aureus 101 indicate similar resistant pattern to four antibiotics. On the contrary, the minimal inhibitory concentrations values for chloramphenicol and sulfadimethoxine were much higher in SCV102 than that of S. aureus 101. To the best of our knowledge this is the first time the isolation of S. aureus SCV102 from a persistent bovine mastitis has been reported in Beijing (China). This study suggests that SCV102 isolate may be an important contributor to persistent bovine mastitis.
authors.affiliation: College of Veterinary Medicine, China Agricultural University, Beijing, China.
authors.forename: Rashad
authors.initials: R
authors.lastname: Alkasir
authors.forename: Xiuquan
authors.initials: X
authors.lastname: Liu
authors.forename: Mohammad
authors.initials: M
authors.lastname: Zahra
authors.forename: Miro
authors.initials: M
authors.lastname: Ferreri
authors.forename: Jingliang
authors.initials: J
authors.lastname: Su
authors.forename: Bo
authors.initials: B
authors.lastname: Han
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D002417:Cattle; D002681:China; D002701:Chloramphenicol / Q000494:pharmacology / Q000627:therapeutic use; D002908:Chronic Disease; D015169:Colony Count, Microbial / Q000662:veterinary; D004847:Epithelial Cells / Q000187:drug effects / Q000382:microbiology; D005260:Female; D006801:Humans; D008414:Mastitis, Bovine / Q000188:drug therapy / Q000382:microbiology*; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000382:microbiology / Q000662:veterinary*; D013211:Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development* / Q000302:isolation & purification; D013412:Sulfadimethoxine / Q000494:pharmacology / Q000627:therapeutic use; D013936:Thymidine / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D013412:Sulfadimethoxine; D002701:Chloramphenicol; D013936:Thymidine