The human clone ST22 SCCmec IV methicillin-resistant Staphylococcus aureus isolated from swine herds and wild primates in Nepal: is man the common source?
Marilyn C Roberts, Prabhu Raj Joshi, Alexander L Greninger, Daira Melendez, Saroj Paudel, Mahesh Acharya, Nabin Kishor Bimali, Narayan P Koju, David No, Mukesh Chalise, Randall C Kyes
Author Information
Marilyn C Roberts: Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98195, USA.
Prabhu Raj Joshi: Central Department of Microbiology, Tribhuvan University, Kirtipur, Kathmandu, Nepal.
Alexander L Greninger: Laboratory Medicine, University of Washington, Seattle, WA 98102, USA.
Daira Melendez: Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98195, USA.
Saroj Paudel: Goldengate International College, Tribhuvan University, Battisputali, Kathmandu, Nepal.
Mahesh Acharya: Central Department of Microbiology, Tribhuvan University, Kirtipur, Kathmandu, Nepal.
Narayan P Koju: NAMI College, University of Northampton, Kathmandu, Nepal and Nepal Engineering College, Center for Postgraduate Studies, Pokhara University, Nepal.
David No: Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98195, USA.
Mukesh Chalise: Nepal Biodiversity Research Society and Central Department of Zoology, Tribhuvan University, Kirtipur, Kathmandu, Nepal.
Randall C Kyes: Departments of Psychology and Global Health, Center for Global Field Study, and Washington National Primate Research Center, University of Washington, Seattle, WA 98195, USA.
Swine nasal samples [n = 282] were collected from 12 randomly selected farms around Kathmandu, Nepal, from healthy animals. In addition, wild monkey (Macaca mulatta) saliva samples [n = 59] were collected near temples areas in Kathmandu using a non-invasive sampling technique. All samples were processed for MRSA using standardized selective media and conventional biochemical tests. MRSA verification was done and isolates characterized by SCCmec, multilocus sequence typing, whole genome sequencing [WGS] and antibiotic susceptibilities. Six (2.1%) swine MRSA were isolated from five of the different swine herds tested, five were ST22 type IV and one ST88 type V. Four (6.8%) macaques MRSA were isolated, with three ST22 SCCmec type IV and one ST239 type III. WGS sequencing showed that the eight ciprofloxacin resistant ST22 isolates carried gyrA mutation [S84L]. Six isolates carried the erm(C) genes, five isolates carried aacC-aphD genes and four isolates carried blaZ genes. The swine linezolid resistant ST22 did not carry any known acquired linezolid resistance genes but had a mutation in ribosomal protein L22 [A29V] and an insertion in L4 [68KG69], both previously associated with linezolid resistance. Multiple virulence factors were also identified. This is the first time MRSA ST22 SCCmec IV has been isolated from livestock or primates.
