Related Experiment Videos
Antiseptic susceptibility and distribution of antiseptic-resistance genes in methicillin-resistant Staphylococcus
1Department of Microbiology, School of Pharmacy, Tokyo University of Pharmacy and Life Science, Japan. noguchin@ps.toyaku.ac.jp
Abstract:
We examined the antiseptic susceptibilities and distribution of antiseptic-resistance genes qacA and smr in 98 isolates of methicillin-resistant Staphylococcus aureus obtained in 1992. Seventy-one strains were resistant to antiseptics. The qacA and smr genes were detected in 10 and 20 strains, respectively. The remaining 41 strains without qacA and smr were divided into two groups that exhibited low-level (n = 22) and high-level (n = 19) resistance to acriflavin. DNA cloning and sequencing suggested that norfloxacin-resistance gene norA was responsible for the high-level resistance to acriflavin. Our results indicated that four or more antiseptic-resistance genes exist in methicillin-resistant S. aureus and that antiseptic-resistant methicillin-resistant S. aureus strains without qacA and smr are widely spread in Japan.
Insights
Methicillin-resistant Staphylococcus aureus (MRSA) strains show widespread antiseptic resistance in Japan. Multiple resistance genes, beyond qacA and smr, contribute to this phenomenon, necessitating further investigation.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Methicillin-resistant Staphylococcus aureus (MRSA) poses a significant public health threat.
- Antiseptic resistance in MRSA is a growing concern, potentially compromising infection control.
- The prevalence and genetic basis of antiseptic resistance in MRSA isolates from Japan in 1992 were not fully understood.
Purpose of the Study:
- To investigate the antiseptic susceptibilities of MRSA isolates.
- To determine the distribution of antiseptic-resistance genes, specifically qacA and smr, in these isolates.
- To identify novel genes or mechanisms contributing to antiseptic resistance in MRSA.
Main Methods:
- Antiseptic susceptibility testing was performed on 98 MRSA isolates collected in 1992.
- Polymerase chain reaction (PCR) was used to detect the presence of qacA and smr genes.
- DNA cloning and sequencing were employed to identify genes responsible for acriflavin resistance in strains lacking qacA and smr.
Main Results:
- Seventy-one out of 98 (72.4%) MRSA isolates exhibited resistance to at least one antiseptic.
- The qacA gene was detected in 10 isolates, and the smr gene was found in 20 isolates.
- Forty-one isolates without qacA or smr showed varying levels of acriflavin resistance, with 19 exhibiting high-level resistance attributed to the norfloxacin-resistance gene norA.
Conclusions:
- At least four distinct antiseptic-resistance genes are present in MRSA.
- Antiseptic-resistant MRSA strains lacking the common qacA and smr genes are prevalent in Japan.
- The findings highlight the complex genetic landscape of antiseptic resistance in MRSA and its potential impact on clinical settings.