Capturing the cloud of diversity reveals complexity and heterogeneity of MRSA carriage, infection and transmission

Abstract

Genome sequencing is revolutionizing clinical microbiology and our understanding of infectious diseases. Previous studies have largely relied on the sequencing of a single isolate from each individual. However, it is not clear what degree of bacterial diversity exists within, and is transmitted between individuals. Understanding this ‘cloud of diversity’ is key to accurate identification of transmission pathways. Here, we report the deep sequencing of methicillin-resistant Staphylococcus aureus among staff and animal patients involved in a transmission network at a veterinary hospital. We demonstrate considerable within-host diversity and that within-host diversity may rise and fall over time. Isolates from invasive disease contained multiple mutations in the same genes, including inactivation of a global regulator of virulence and changes in phage copy number. This study highlights the need for sequencing of multiple isolates from individuals to gain an accurate picture of transmission networks and to further understand the basis of pathogenesis.

Next-Generation Sequencing Confirms Presumed Nosocomial Transmission of Livestock-Associated Methicillin-Resistant Staphylococcus aureus in the Netherlands

“…However, it obviously belonged to the outbreak, suggesting that an LA-MRSA strain colonizing or infecting different sites within the same person may evolve independently over time. Recent reports that applied whole-genome sequencing on multiple colonies from the same person also identified a cloud of diversity among the isolates (21,34,35). These studies were carried out on ST22 and ST239 MRSA isolates, but similar findings might be expected from LA-MRSA.…”

Livestock-Associated, Antibiotic-Resistant Staphylococcus aureus Nasal Carriage and Recent Skin and Soft Tissue Infection among Industrial Hog Operation Workers

“…Finally, we assessed transmission events based on shared spa types between household members. However, recent whole genome sequencing studies have demonstrated that shared spa types may not indicate true transmission events; both false positives and false negatives are possible [46,47]. …”

Genomic insights into the emergence and spread of international clones of healthcare-, community- and livestock-associated meticillin-resistant Staphylococcus aureus : Blurring of the traditional definitions

“…In contrast, in the UK where the use of clindamycin is limited, all EMRSA-15 ermC leader peptides were intact, therefore making these isolates susceptible to clindamycin [21]. The human EMRSA-15 epidemic has also spread into the companion animal population [22,23], with veterinary hospitals also being healthcare settings that may experience high levels of transmission [24]. A c c e p t e d M a n u s c r i p t 12 documented in Portugal, Singapore and Australia [25][26][27].…”