Antimicrobial Resistance Profile and Molecular Characteristics of Staphylococcus aureus Isolates from Hospitalized Adults in Three Regions of Vietnam.

This study aimed to investigate antimicrobial resistance profile, multidrug resistance (MDR), and molecular characteristics of pathogenic Staphylococcus aureus isolates from hospitalized Vietnamese adults. Two hundred and twenty-three pathogenic S. aureus isolates were obtained from the hospitals located in 3 regions of Vietnam. The minimum inhibitory concentrations were determined to detect the antibiotic susceptibility of the isolates. The molecular characteristics of S. aureus isolates were investigated through antibiotic-resistant genes analysis, staphylococcal cassette chromosome mec typing, pulsed-field gel electrophoresis, and multilocus sequence typing. Substantial differences among the 3 regions were found in the prevalence rates of methicillin-resistant S. aureus (north: 48.6%, central: 58.7%, south: 78.9%) and MDR (north: 65.8%, central: 79.7%, and south: 84.2%). The prevalence rates of the genes tetK/M, aacA/aphD, ermA/B/C, and mecA increased substantially from north to south. ST188-SCCmecIV and ST239-SCCmecII isolates were most commonly found in the 2 largest clusters. ST188 predominance was observed in the largest cluster in methicillin-resistant and methicillin-sensitive S. aureus isolates, including SCCmecIII and SCCmecIVa, in fatal cases. Our results revealed a high occurrence of MDR and possible north-south trend in antibiotic resistance profile, MDR patterns, and frequency of antibiotic-conferring genes among S. aureus isolates. ST188 predominance raises concerns about the global importance of host-adapted ST188 in East Asian populations.