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.
Keywords: Vietnamese adults; methicillin-resistant Staphylococcus aureus (MRSA); molecular characteristics; multidrug resistance.