Related Experiment Video
Updated: Aug 3, 2026
Biosensor for Detection of Antibiotic Resistant Staphylococcus Bacteria
Published on: May 8, 2013
Investigation of aminoglycoside modifying enzyme genes in methicillin-resistant staphylococci
Nurittin Ardic1, Baris Sareyyupoglu, Mustafa Ozyurt
1Department of Microbiology and Clinical Microbiology, Gulhane Military Medical Academy, GATA Haydarpasa Training Hospital, 81327 Uskudar/Istanbul, Turkey. nurittinardic@yahoo.com
Abstract:
Methicillin-resistant staphylococci may also be resistant to some other antibiotics as well as beta-lactams. In this study, co-existence of resistance to methicillin and aminoglycosides was genetically investigated in staphylococci. A total of 50 staphylococci from in-patients, 17 Staphylococcus aureus and 33 coagulase negative staphylococci (CNS) that contained mecA (gene encoding PBP 2a, an altered penicillin-binding protein) determined by polymerase chain reaction (PCR) were included in the study. Aminoglycoside modifying enzyme (AME) genes were investigated using multiplex-PCR. Aminocyclitol-6'-acetyltransferase-aminocyclitol-2''-phosphotransferase [aac(6')/aph(2'')] gene (encoding bifunctional acetyltransferases/phosphotransferases) was determined in 66% of the isolates, aminocyclitol-4'-adenylytransferase (ant(4')-Ia) gene (encoding phosphotransferases) in 24%, and aminocyclitol-3'-phosphotransferase (aph(3')-IIIa) gene (encoding nucleotidyltransferases) in 8%. Two isolates contained all these three genes. Thirty-six (72%) isolates had at least one of these genes. Three CNS and one S. aureus isolates sensitive to oxacillin had the mecA gene. In conclusion, a high rate of aminoglycoside resistance was determined in methicillin-resistant staphylococci. The aac(6')/aph(2'') was the most frequently detected.
Insights
Methicillin-resistant staphylococci frequently exhibit aminoglycoside resistance. The bifunctional acetyltransferase/phosphotransferase gene [aac(6')/aph(2')] was the most common genetic determinant identified in these resistant bacteria.
Area of Science:
- Microbiology
- Genetics
- Infectious Diseases
Background:
- Methicillin-resistant staphylococci (MRS) can exhibit resistance to multiple antibiotic classes beyond beta-lactams.
- Co-resistance to methicillin and aminoglycosides poses a significant clinical challenge.
- Genetic investigation of resistance mechanisms is crucial for understanding bacterial adaptation.
Purpose of the Study:
- To genetically investigate the co-existence of methicillin and aminoglycoside resistance in staphylococcal isolates.
- To identify the specific aminoglycoside-modifying enzyme (AME) genes present in methicillin-resistant staphylococci (MRS).
- To determine the prevalence of different AME genes within a collection of clinical staphylococcal isolates.
Main Methods:
- Polymerase chain reaction (PCR) was used to detect the mecA gene, indicating methicillin resistance.
- Multiplex-PCR was employed to identify various aminoglycoside-modifying enzyme (AME) genes.
- Fifty clinical staphylococcal isolates (17 Staphylococcus aureus and 33 coagulase-negative staphylococci) carrying the mecA gene were analyzed.
Main Results:
- The bifunctional acetyltransferase/phosphotransferase gene [aac(6")/aph(2")] was detected in 66% of isolates.
- The phosphotransferase gene (ant(4">-Ia) was found in 24% of isolates, and the nucleotidyltransferase gene (aph(3">-IIIa) in 8%.
- A high rate of aminoglycoside resistance was observed, with 72% of MRS isolates possessing at least one AME gene.
Conclusions:
- Methicillin-resistant staphylococci demonstrate a high prevalence of aminoglycoside resistance.
- The aac(6")/aph(2") gene is the most frequently identified genetic factor contributing to aminoglycoside resistance in these isolates.
- Understanding the genetic basis of co-resistance is vital for effective antimicrobial stewardship.
More Related Videos
Related Concept Videos
01:25Mechanism of Antibiotic Resistance in MRSA
01:25Clinical Significance of Antibiotic Resistance