The study of reduced susceptibility of methicillin resistant Staphylococcus aureus to various antibiotics with special reference to glycopeptides in a tertiary care hospital in central India

Swati S. Kale, Ashwini Patil


Background: Staphylococcus aureus has emerged over the past several decades as a leading cause of hospital-associated and community acquired infections. Methicillin resistant S. aureus (MRSA), which are often resistant to several classes of antibiotics, is the most common cause of nosocomial infections and pose a great threat to the world. Vancomycin is regarded as the first-line drug for treatment of MRSA but resistance to this drug is being reported now a day.

Methods: It was carried out for a period between January 2014 to June 2017 in the microbiology diagnostic laboratory. MRSA detection was performed by cefoxitin disk diffusion method. Screening for the vancomycin intermediate and the vancomycin resistant S. aureus (VISA and VRSA respectively) was carried out by using vancomycin screen. MIC (minimum inhibitory concentration) of vancomycin was tested by agar dilution method and E strip on all MRSA isolates.

Results: A total of 287 S. aureus clinical isolates were included in the study. All MRSA were inoculated on vancomycin screen agar. Visible growth was present in 8 isolates. Five (3.73%) MRSA isolates with MIC of 4 were termed VISA (vancomycin intermediate S. aureus) by agar dilution method. Six isolates had the MIC of 4 and were termed as VISA.

Conclusions: As disc diffusion method is not recommended by CLSI for S. aureus, vancomycin screen agar and MIC determination by either of the methods viz. agar dilution or E test can be used.


Staphylococcus aureus, Methicillin resistant S. aureus, Vancomycin intermediate S. aureus, Minimum inhibitory concentration

Full Text:



Joshi S, Ray P, Manchanda V, Bajaj J, Chitnis DS, Gautam V. Methicillin resistant Staphylococcus aureus (MRSA) in India: Prevalence and susceptibility pattern. Indian J Med Res. 2013;137:363–9.

Rajaduraipandi K, Mani KR, Panneerselvam K, Mani M, Bhaskar M, Manikandan P. Prevalence and antimicrobial susceptibility pattern of methicillin resistant Staphylococcus aureus: A multicentre study. Indian J Med Micrbiol. 2006;24:34-8.

Bhattacharya S, Pal K, Chatterjee M, Banerjee M, Kundu PK, Niyogi SK. Vancomycin intermediate Staphylococcus aureus isolated from a tertiary care hospital in Kolkata. IOSR-JDMS. 2013;5(2):19-23.

Koneman EW, Allen S, Janda W, Schreckenberger P, Winn WC. The Gram positive cocci part I;Staphylococci and related organisms. Color Atlas and Textbook of Diagnostic Microbiology, 6th edn. New York: Lippincott; 2006: 624-66.

Performance Standards for Antimicrobial Susceptibility Testing; Twenty seventh informational supplement.CLSI document. M100-S20. Pennsylvania: Clinical and Laboratory Standards Institute; 2017.

Baur AW, Kirby WMM, Sherris JC, Turck M. Antibiotic susceptibility testing by a standardized single disk method. Am J Clin Pathol. 1966;45:493-6.

Performance Standards for Antimicrobial Susceptibility Testing; Twentieth informational supplement. CLSI document. M100-S20. Pennsylvania: Clinical and Laboratory Standards Institute; 2010.

Mathews A, Thomas M, Appalaraju B, Jayalakshmi J. Evaluation and comparison of tests to detect methicillin resistant S. aureus. Indian J Pathol Microbiol. 2010;53:79-82.

Hiramatsu K. Vancomycin-resistant Staphylococcus aureus: a new model of antibiotic resistance. Lancet Infect Dis. 2001;1:147-55.

Saderi H , Owlia P , Maleki Z , Habibi M , Rahmati N. Susceptibility to Vancomycin in Staphylococcus aureus Isolated From Patients of Four University-Affiliated Hospitals in Tehran. Iranian J Pathol. 2008;3(3):161-6.

Lalitha MK. Manual on Antimicrobial Susceptibility Testing, 2005. Available at: Accessed on 28 January 2018.

Cruickshank R, Duguid JP, Marmion BP, Swain RHA. The Practice of Medical Microbiology. 12th Edn, vol II. Edinburgh London and New York: Churchill Livingstone; 1975: 197-199.

Deresinski S. Methicillin-resistant Staphylococcus aureus: an evolutionary, epidemiologic, and therapeutic odyssey. Clin Infect Dis. 2005;40:562-73.

Tiwari HK, Sapkota D, Sen RM. High prevalence of multidrug-resistant MRSA in a tertiary care hospital of northern India. Infection Drug Resistance. 2008;1:57–61.

Shantala GB, Shetty AS, Rao RK, Vasudeva, Nagarathnamma T. Detection of inducible clindamycin resistance in clinical isolates of Staphylococcus aureus by the disc diffusion induction test. J Clinical Diagnostic Res. 2011;5:35-7.

Sharma NK, Garg R, Baliga S, Bhat KG. Nosocomial infections and drug susceptibility patterns in methicillin sensitive and methicillin resistant Staphylococcus aureus. J Clin Diagn Res. 2013;7:2178-80.

Kulkarni S, Khare A, Kaur DC. Prevalence of methicillin resistant staphylococcus aureus- A study in a tertiary care rural hospital. Indian J Basic Applied Med Res. 2014;3(3):414-21.

Bouchiat C, El-Zeenni N, Chakrakodi B, Nagaraj S, Arakere G, Etienne J. Epidemiology of Staphylococcus aureus in Bangalore, India: emergence of the ST217 clone and high rate of resistance to erythromycin and ciprofloxacin in the community. New Microbes New Infect. 2015;7:15–20.

Sharma P, Vishwanath G. Study of vancomycin susceptibility in methicillin-resistant Staphylo-coccus aureus isolated from clinical samples. Ann Trop Med Public Health. 2013;5:178-80.

Riederer K, Shemes S, Chase P, Musta A, Mar A, Khatib R. Detection of intermediately vancomycin-susceptible and heterogeneous Staphylococcus aureus isolates: comparison of E test and agar screening methods. J Clin Microbiol. 2011;49(6):2147–50.

Satola SW, Farley MM, Anderson KF, Patel JB. Comparison of detection methods for heteroresistant vancomycin-intermediate Staphylococcus aureus with the population analysis profile method as the reference method. J Clin Microbiol. 2011;49:177–83.

Liaqat F, Sheikh AA, Nazir J, Hussain T, Rabbani M, Shaheen AY, et al. Isolation identification and control of vancomycin resistant Staphylococcus aureus. Pak J Pharm Sci. 2015;28(3):997-1004.

Sharma NK, Garg R, Baliga S, Bhat KG. Nosocomial infections and drug susceptibility patterns in methicillin sensitive and methicillin resistant Staphylococcus aureus. J Clin Diagn Res. 2013;7:2178-80.

Tiwari HK, Sen MR. Emergence of vancomycin resistant Staphylococcus aureus (VRSA) from a tertiary care hospital from northern part of India. BMC Infect Dis. 2006;6:156.

Saha B, Singh A K, Ghosh A, Bal M. Identification and characterization of a vancomycin-resistant Staphylococcus aureus isolated from Kolkata (South Asia). J Med Microbiol. 2008;57:72-9.

Charles PGP, Ward PB, Johnson PDR, Howden BP, Grayson ML. Clinical Features Associated with Bacteremia Due to Heterogeneous Vancomycin-Intermediate Staphylococcus aureus. Clin Infectious Dis. 2004;38(3):448–51.

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

Tandel K, Praharaj AK, Kumar S. Differences in vancomycin MIC among MRSA isolates by agar dilution and E test method. Ind J Med Microbiol. 2012;30:453-5.

Chaudhari CN, Tandel K, Grover N, Bhatt P, Sahni AK, Sen S, et al. In vitro vancomycin susceptibility amongst methicillin resistant Staphylococcus aureus. Med J Armed Forces India. 2014;70:215-9.

Prakash V, Lewis JS, Jorgensen JH. Vancomycin MICs for Methicillin-Resistant Staphylococcus aureus Isolates Differ Based upon the Susceptibility Test Method used. Antimicrobial Agents Chemotherapy. 2008;52:4528.

Havaei S, Azimian A, Fazeli H, Naderi M, Ghazvini K, Samiee SM, et al. Genetic Characterization of Methicillin Resistant and Sensitive, Vancomycin Intermediate Staphylococcus aureus Strains Isolated from Different Iranian Hospitals. ISRN Microbiol. 2012;2012:215-75.

Liaqat F, Sheikh AA, Nazir J, Hussain T, Rabbani M, Shaheen AY, et al. Isolation identification and control of vancomycin resistant Staphylococcus aureus. Pak J Pharm Sci. 2015;28(3):997-1004.

Sancak B, Yagci S, Gur D, Gulay Z, Ogunc D, Soyletir G, et al. Vancomycin and daptomycin Minimum Inhibitory Concentration distribution and occurrence of heteroresistance among methicillin-resistant Staphylococcus aureus blood isolates in Turkey. BMC Infectious Dis. 2013;13:583.

Bhatawadekar S, Chattopadhyay A. Quinpristin-dalfopristin resistance among methicillin-resistant strains of staphylococci. Indian J Pharmacol. 2010;42:56.