Indian Journal of Medical Research

CORRESPONDENCE
Year
: 2012  |  Volume : 135  |  Issue : 3  |  Page : 441-

Vancomycin resistance among MRSA


V Anil Kumar 
 Department of Microbiology, Amrita Institute of Medical Sciences, Ponekara, Kochi 682 041, Kerala, India

Correspondence Address:
V Anil Kumar
Department of Microbiology, Amrita Institute of Medical Sciences, Ponekara, Kochi 682 041, Kerala
India




How to cite this article:
Kumar V A. Vancomycin resistance among MRSA.Indian J Med Res 2012;135:441-441


How to cite this URL:
Kumar V A. Vancomycin resistance among MRSA. Indian J Med Res [serial online] 2012 [cited 2020 Sep 25 ];135:441-441
Available from: http://www.ijmr.org.in/text.asp?2012/135/3/441/95641


Full Text

Sir,

The study by Thati et al[1] brings to limelight an alarming situation of vancomycin resistance in methicillin resistant Staphylococcus aureus (MRSA) in south India. There are certain points mentioned in the article which need clarification.

The authors have not mentioned how they screened the isolates for MRSA. There is no point in testing oxacillin and methicillin together and they require a different temperature of incubation.

DNA extraction step in the PCR could have been elaborated.How did the authors validate the PCR? There is no mention of running a positive control.It is absurd to mention that MRSA isolates were also resistant to ceftazidime. MRSA by definition are considered resistant to all beta- lactam antibiotics irrespective of the zones of inhibition.The authors mention that all vancomycin resistant S. aureus (VRSA) isolates were inducible for clindamycin resistance but the Table shows that two of the isolates (VRSA3 & VRSA6) were susceptible to erythromycin. How did authors determine inducible resistance to clindamycin when the isolates were susceptible to erythromycin?How was the presence of mecA (PCR or latex agglutination) confirmed?The authors have described an alarming situation but fail to suggest an alternative for treatment. They should have tested linezolid and quinopristin/dalfopristin and reported their sensitivity.The authors have done MIC of vancomycin but failed to mention the MIC 90 and MIC 50 values.The authors should have highlighted the presence or absence of MIC creep in their isolates.The authors should have determined the correlation between the diameters of vancomycin disc diffusion and MIC especially when they were in the intermediate range.The authors have not mentioned about the VISA strains or their PCR results?The authors should have mentioned the clinical source of at least the VISA and VRSA isolates.

References

1Thati V, Shivannavar CT, Gaddad SM. Vancomycin resistance among methicillin resistant Staphylococcus aureus isolates from intensive care units of tertiary care hospitals in Hyderabad. Indian J Med Res 2011; 134 : 704-8.