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Updated: Sep 11, 2025
Multiplex PCR Assay for Typing of Staphylococcal Cassette Chromosome Mec Types I to V in Methicillin-resistant Staphylococcus aureus
Published on: September 5, 2013
The emerging threat of multidrug-resistant mecA gene-positive coagulase-negative Staphylococci
Samira Fattah Hamid1, Aza Bahadeen Taha2, Shler Qasim Hussien3
1Department of Medical Microbiology, College of Health Sciences, Hawler Medical University, Kurdistan Region, Iraq.
Background And Objectives:
Coagulase-negative staphylococci (CoNS), previously classified as normal bacterial flora, have recently been associated with serious infectious diseases. The clinical isolation rate of these bacteria has increased in parallel with a rising prevalence of antibiotic resistance. Therefore, this study aims to determine the prevalence and species diversity of CoNS and their antibiotic susceptibility patterns.
Materials And Methods:
Two hundred samples were collected from patients attending outpatient clinics. Bacterial genus, species, and antimicrobial susceptibility patterns were confirmed by the Vitek2 system. The mecA gene was then detected in all isolated bacteria using a polymerase chain reaction.
Results:
The most frequently isolated bacterium was Staphylococcus haemolyticus accounting for 37.83% of the isolates and was identified in different specimens. The antibiotic susceptibility profile illustrated the highest resistance against cefoxitin, followed by erythromycin, tetracycline, gentamicin, levofloxacin, clindamycin, and tobramycin. The mecA gene was detected in 95.49%, and all isolates demonstrated resistance to one or more classes of antibiotics. The highest degree of multiple resistance involved six classes of antibiotics.
Conclusion:
Methicillin resistance in coagulase-negative staphylococci is alarmingly high. Periodic surveillance of multidrug-resistant CoNS is essential to monitor changes in their antimicrobial susceptibility and to prevent their transition from opportunistic pathogens to regular pathogens.
Insights
Coagulase-negative staphylococci (CoNS) infections are rising, with high rates of antibiotic resistance. Surveillance is crucial to manage these opportunistic pathogens and prevent further spread of antimicrobial resistance.
Area of Science:
- Microbiology
- Infectious Diseases
- Antimicrobial Resistance
Background:
- Coagulase-negative staphylococci (CoNS) are increasingly linked to severe infections.
- Rising antibiotic resistance complicates CoNS treatment and management.
Purpose of the Study:
- To investigate the prevalence and species diversity of CoNS.
- To determine the antibiotic susceptibility patterns of CoNS isolates.
Main Methods:
- Collected 200 samples from outpatient clinics.
- Utilized Vitek2 system for bacterial identification and antimicrobial susceptibility testing.
- Employed polymerase chain reaction (PCR) to detect the mecA gene.
Main Results:
- Staphylococcus haemolyticus was the most common isolate (37.83%).
- High resistance observed against cefoxitin, erythromycin, and tetracycline.
- The mecA gene was present in 95.49% of isolates, indicating widespread methicillin resistance.
Conclusions:
- Methicillin resistance among CoNS is alarmingly prevalent.
- Continuous monitoring of multidrug-resistant CoNS is vital.
- Preventing the transition of CoNS from opportunistic to regular pathogens is essential.
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