Comparative Analysis of Multidrug-Resistant, Non-Multidrug-Resistant, and Archaic Methicillin-Resistant Staphylococcus aureus Isolates from Central Sydney, Australia

Abstract

In this study, the phenotypic and genotypic characteristics of 50 methicillin-resistant Staphylococcus aureus (MRSA) isolates (43 contemporary and 7 archaic strains from the mid-1960s) from four Sydney hospitals in the central Sydney area were compared. Phenotypic analysis based on antibiotic profiles and phage typing patterns categorized the MRSA isolates into three major groups: multidrug resistant (mMRSA), non-multidrug resistant (nmMRSA), and archaic. The nmMRSA isolates could be further subdivided into nmMRSA group 1, which was phage typeable and similar to the archaic group; nmMRSA group 2, which was non-phage typeable and only resistant to ciprofloxacin; and nmMRSA group 3, which was also nontypeable and generally resistant to other antibiotics. The characterization of all five phenotypic groups was then extended by genetic analysis. Restriction fragment length polymorphism (RFLP) analysis showed the 50 isolates could be sorted into 20 group-specific pulsotypes. mecI gene deletions and mutations at various percentages among the five MRSA groups were detected by sequencing. Several mec promoter mutations were also found. The overall findings indicated that nmMRSA strains may have independently acquired mec DNA and are more likely to be newly emergent strains than nmMRSA variants.

Identification and Discrimination of Methicillin Resistant Staphylococcus aureus Strains Isolated from Burn Wound Sites Using PCR and Authentication with MALDI-TOF–MS

“…In the present study, resistance observed for MRSA strains isolated from burn wound site was on par with previous reports [30]. However, isolates S8 and S10, showed resistance against ampicillin, amoxicillin and tetracycline and this observation was supported by the previous observations [31] implying resistant S. aureus traits were most common in hospital community.…”

Detection of Methicillin-Resistant Staphylococcus aureus Using mecA/nuc Genes and Antibiotic Susceptibility Profile of Malaysian Clinical Isolates

“…Several studies also noted the presence of non multidrug resistant MRSA strains often associated with community-acquired MRSA (Watson et al 2003;Ala'Aldeen 2002). Isolate UM11, a methicillin-sensitive S. aureus (MSSA) strain, shows multiple-resistance trait against ampicillin, norfloxacin and fusidic acid.…”

Perbedaan Nilai Hitung Neutrofil Absolut Antara Infeksi Methicillin-Resistant Staphyloccocus aureus yang Berasal dari Rumah Sakit dengan yang dari Komunitas

“…Dikatakan CA-MRSA apabila resisten ≤ 2 antibiotik non beta laktam (eritromisin, tetrasiklin, kotrimoksasol, dan kuinolon) dan HA-MRSA apabila resisten ≥ 3 antibiotik non beta laktam. 10,11 Uji hipotesis menggunakan uji T pada data dengan distribusi normal dan uji Mann-Whitney pada data dengan distribusi tidak normal. Program analisis yang digunakan adalah SPSS versi 22.…”