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Updated: May 18, 2026
Biosensor for Detection of Antibiotic Resistant Staphylococcus Bacteria
Published on: May 8, 2013
Inducible clindamycin resistance in Staphylococcus aureus isolates recovered from Mashhad, Iran
1Mashhad Medical Microbiology Student Research Group, Mashhad University of Medical Sciences, Mashhad.
Background And Objectives:
Staphylococcus aureus is an important agent in hospital and community-associated infections, causing high morbidity and mortality. Introduction of the new antimicrobial classes for this pathogen has been usually followed by the emergence of resistant strains through multiple mechanisms. For instance, resistance to clindamycin (CLI)can be constitutive or inducible. Inducible clindamycin resistance which may lead to treatment failure can simply be identified by performing D-test. The aim of this study was to determine the prevalence of inducible clindamycin resistance among Staphylococcus aureus isolates by D-test method.
Materials And Methods:
This was a cross-sectional study conducted on 211 non-duplicated S. aureus isolates in Imam Reza hospital of Mashhad during 2010. Susceptibility to oxacillin, cefoxitin, erythromycin and clindamycin was performed by agar disk diffusion method according to CLSI guidelines and D-shaped clindamycin susceptibility patterns where considered as D-test positive (D(+)).
Results:
Of 211 S. aureus isolates,88 (41.7%) were methicillin resistant. It was found that of 88 MRSA isolates, 78 (88.6%) were erythromycin (ERY) resistant and 46 (52.3%) were CLI resistant. ERY and CLI resistance in MSSA strains was 22% and 10.6% respectively. Inducible clindamycin resistance was detected in 18 (20.5%) MRSA isolates. 47(53.4%) of MRSA isolates and 9 (7.3%) of MSSA showed constitutive MLS(B) phenotype.
Conclusion:
In conclusion, we found a high prevalence of inducible clindamycin resistance phenotype in our region. We recommend that whenever clindamycin is intended to be used for S. aureus infections, D-test should be performed to facilitate the appropriate treatment of patients.
Insights
Inducible clindamycin resistance is common in Staphylococcus aureus infections. Performing the D-test is recommended to guide appropriate clindamycin treatment for patients.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Antimicrobial Resistance
Background:
- Staphylococcus aureus is a significant cause of hospital and community-acquired infections.
- Antimicrobial resistance, including to clindamycin, is a growing concern.
- Inducible clindamycin resistance can lead to treatment failure and is detectable via the D-test.
Purpose of the Study:
- To determine the prevalence of inducible clindamycin resistance in Staphylococcus aureus isolates.
- To evaluate the utility of the D-test for identifying inducible clindamycin resistance.
Main Methods:
- A cross-sectional study of 211 Staphylococcus aureus isolates was conducted.
- Antimicrobial susceptibility testing, including clindamycin and erythromycin, was performed using agar disk diffusion.
- The D-test was used to identify inducible clindamycin resistance patterns.
Main Results:
- 41.7% of isolates were methicillin-resistant Staphylococcus aureus (MRSA).
- Inducible clindamycin resistance was detected in 20.5% of MRSA isolates.
- Constitutive MLS(B) phenotype was observed in 53.4% of MRSA and 7.3% of methicillin-susceptible S. aureus (MSSA) isolates.
Conclusions:
- A high prevalence of inducible clindamycin resistance was found in the study region.
- The D-test is a valuable tool for identifying inducible clindamycin resistance in Staphylococcus aureus.
- Performing the D-test is recommended to ensure appropriate clindamycin therapy for S. aureus infections.
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