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Year : 2011  |  Volume : 29  |  Issue : 3  |  Page : 313--314

Glycopeptides-Important treatment option for methicillin-resistant Staphylococcus aureus

S Arora, U Arora 
 Department of Microbiology, Govt. Medical College, Amritsar, Punjab, India

Correspondence Address:
S Arora
Department of Microbiology, Govt. Medical College, Amritsar, Punjab
India

How to cite this article:
Arora S, Arora U. Glycopeptides-Important treatment option for methicillin-resistant Staphylococcus aureus.Indian J Med Microbiol 2011;29:313-314

How to cite this URL:
Arora S, Arora U. Glycopeptides-Important treatment option for methicillin-resistant Staphylococcus aureus. Indian J Med Microbiol [serial online] 2011 [cited 2019 Dec 6 ];29:313-314
Available from: http://www.ijmm.org/text.asp?2011/29/3/313/83922

Full Text

Dear Editor,

The emergence of multidrug-resistant methicillin-resistant Staphylococcus aureus (MDR MRSA) resulted in the establishment of selective pressure that lead to development of vancomycin intermediate and vancomycin-resistant Staphylococcus aureus (VISA and VRSA). [1],[2] The increasing levels of MIC of vancomycin in MRSA [3] must act as an alarm for vancomycin abusers.

Vancomycin resistance is difficult to detect in the clinical microbiology laboratory as it is not the homogenous characteristic of the majority of staphylococci. Disc diffusion sensitivity testing using the standard 30 μg vancomycin disc frequently misclassifies intermediately susceptible isolates as fully susceptible. [4] This study composed of 250 consecutive coagulase positive staphylococci isolated from various clinical specimens of indoor patients to know the presence of VISA/VRSA. All the isolates were subjected to susceptibility testing by Kirby-Bauer disc diffusion method and brain heart infusion vancomycin screen agar (BHI-VSA) test (6 μg vancomycin/ml). Minimum inhibitory concentration (MIC) for vancomycin and oxacillin was calculated by broth macrodilution method.

Tests were performed according to CLSI criteria. [5] ATCC 29213 strain was used as a reference strain. The 30 μg cefoxitin disc and MIC testing revealed 115 (46%) MRSA strains. All isolates including MRSA were sensitive to vancomycin by all the three methods used. A total of 115 (46%) strains showed MIC of 0.5 μg/ml, 128 (51.2%) of 1 μg/ml, and 7 (2.8%) of 2 μg/ml against vancomycin. The strains that showed MIC of 2 μg/ml were cross-checked by E-test and the results matched. Resistance to ciprofloxacin, erythromycin, amikacin, and linezolid among MRSA was 67.8%, 61.7%, 37.4%, and 1.7% respectively.

In contrast to the recent reports of vancomycin intermediate and resistant strains from various parts of the country, [1],[2] our study revealed 100% sensitivity of MRSA to vancomycin. This might be because of less usage of glycopeptides as first line of drug. However, 2.8% strains showed MIC on higher side of the susceptible range, suggesting prudent use of glycopeptides.

References

1Menezes GA, Harish BN, Sujatha S, Vinothini K, Parija SC. Emergence of vancomycin - intermediate Staphylococcus species in southern India. J Med Microbiol 2008;57:911-2.
2Tiwari HK, Sen MR. Emergence of vancomycin resistant Staphylococcus aureus from a tertiary care hospital from northern part of India. BMC Infect Dis 2006;6:156.
3Veer P, Chande C, Chavan S, Wabale V, Chopdekar K, Bade J, et al. Increasing levels of minimum inhibitory concentration vancomycin in methicillin resistant Staphylococcus aureus alarming bell for vancomycin abusers?. Indian J Med Microbiol 2010;28:413-4.
4Srinivasan A, Dick JD, Perl TM. Vancomycin resistance in staphylococci. Clin Microbiol Rev 2002;15:430-8.
5Wayne PA. Clinical and Laboratory Standards Institute. Performance standards for antimicrobial susceptibility testing. 17 th informational supplement 2007. M100-S17.