Prevalence and Antibiotic Resistance Pattern of Staphylococcus aureus isolates from Clinical samples at a Tertiary Care Hospital, North India


  • Dr. Baba Saheb Ambedkar Medical College & Hospital, Department of Microbiology, New Delhi, 110085, India
  • Christian Medical College & Hospital, Department of Microbiology, Ludhiana, Punjab, 141008, India


Background: Staphylococcus aureus (S. aureus) is a well recognized nosocomial and community acquired pathogen which is implicated in causing a wide spectrum of superficial, deep pyogenic infections and toxin mediated illnesses. Localized infections sometimes progress to systemic infections, while ‘spontaneous’ bacteraemia also occur without an evident septic focus, particularly in chronic debilitated immunocompromised patients. Emergence of drug resistance to penicillins and penicillinase-resistant penicillins (i.e., oxacillin and methicillin) is a globally recognized problem. Methicillin Resistant Staphylococcus aureus isolates are also important with respect to the range of nosocomial infections it causes, leading to an increase in the hospital expenditure and mortality or morbidity rate. The increased prevalence of such resistant strains has narrowed down the list of available therapeutic options. Therefore, information regarding the prevalence of S. aureus infections in a health care setting and determining its current antibiotic resistance profile becomes crucial in selecting appropriate treatment regime. Therefore, the current study was done in the department of Microbiology to determine the prevalence of S. aureus infections and the antibiotic resistance pattern of S. aureus isolates from various clinical specimens at our tertiary care hospital in North India. Materials and Methods: A one year prospective study was carried out in the Department of Microbiology, at a tertiary care hospital in North India where non-duplicate strains of S. aureus isolated from various clinical specimens received in the Microbiology laboratory were studied. All S. aureus isolates were subjected to Antibiotic Susceptibility Testing using Kirby Bauer’s disk diffusion method on Mueller Hinton Agar plates in accordance to CLSI guidelines. The antibiotics tested included Penicillin (10U), Amoxicillin-clavulanic acid (20/10μg), Sulphamethoxazole-trimethoprim (1.25/23.75μg), Ciprofloxacin (5μg), Erythromycin (15μg), Clindamycin (2μg), Vancomycin (30μg), Teicoplanin (30μg) and Linezolid (30μg). Results: A total of 23,699 clinical specimens were processed in the laboratory while conducting this study, from which 1233 clinical isolates of S. aureus were identified and processed further. Among all clinical specimens, pyogenic samples (63.1%) yielded maximum number of S. aureus strains followed by blood samples (29.9%) and urine samples (4.8%). S. aureus infection was more evident in hospitalized 71.2% patients than in OPD patients 28.8%. Seasonal variation was also seen in isolation of S. aureus, with a higher percentage of isolates obtained during summer season than during winter season. On antibiotic susceptibility testing, 49.6% strains were Methicillin Resistant. Majority of the isolates were found resistant to Penicillin (92.1%), followed by Erythromycin (59%). Almost half of the total isolates were resistant to Sulphamethoxazole-Trimethoprim (49.3%) followed by Amoxicillin- Clavulanic acid (47.8%), Ciprofloxacin (43.4%) and Clindamycin (18.4%). Antibiotics to which all isolates showed 100% susceptibility included Vancomycin, Teicoplanin, Linezolid. Conclusion: Given the high prevalence of resistance to antibiotics seen in this study, effective treatment of infections caused by multidrug resistant Staphylococcal strains may become challenging. Drugs like Vancomycin, Teicoplanin and Linezolid promise to work as miracle drugs against the multidrug resistant MRSA strains but we need to warrant judicious use of these wonder drugs to conserve them for future use.


Antibiotic Susceptibility Testing, Antimicrobial Resistance, Methicillin Resistant Staphylococcus aureus (MRSA), Staphylococoous aureus

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Yilmaz G, Aydin K, Iskender S, Caylan R, Koksal I. Detection and prevalence of inducible clindamycin resistance in staphylococci. J. Med. Microbiol. 2007; 56:342-345. PMid: 17314364.

Baird D. Staphylococcus: Cluster Forming Gram-Positive Cocci. In: Collee JG, Fraser AG, Marmion BP, Simmons A, editors. Mackie & McCartney Practical Medical Microbiology, 14th ed. Chichester: Churchil Livingstone; 2012. p.245-258.

Gram-positive Cocci: Part-I: Staphylococci and Related Gram-Positive Cocci. In: Winn WC, Allen SD, Janda WM, Koneman EW, Procop GW, Schreckenberger PC, et al, editors. Koneman’s Color Atlas and Textbook of Diagnostic Microbiology, 6th ed. USA: Lippincott Williams and Wilkins; 2006. p.624-661.

Al-Zoubi MS, Al-Tayyar IA, Hussein E, Al Jabali A, Khudairat S. Antimicrobial susceptibility pattern of Staphylococcus aureus isolated from clinical specimens in Northern area of Jordan. Iran. J. Microbiol. 2015; 7:265-272.

Specimen Management. In: Bailey & Scott’s Diagnostic Microbiology. 13th ed. Mosby, USA; 2014. p.53-67.

CLSI. Performance Standards for Antimicrobial Susceptibility Testing; Twenty Third Informational Supplement. CLSI Document M100-S23. Wayne, PA: Clinical and Laboratory Standards Institute; 2013.

Gurung RR, Maharjan P, Chhetri GG. Antibiotic resistance pattern of Staphylococcus aureus with reference to MRSA isolates from pediatric patients. Future Sci. OA. 2020; 6(4):FSO464. PMid: 32257376, PMCid: PMC7117559.

Mukhiya R, Shrestha A, Rai S, Panta K, Singh R, Rai G, et al. Prevalence of Methicillin-Resistant Staphylococcus aureus in Hospitals of Kathmandu Valley. NJST [Internet]. 10 Mar 2013; 13(2):185-190. Cited on 17th Jul 2020.

Pandey S, Raza M, Bhatta C. Prevalence and antibiotic sensitivity pattern of Methicillin- Resistant- Staphylococcus aureus in Kathmandu Medical College - Teaching Hospital. JIOM Nepal. 20th May 2019; 34(1):13-17. Cited on 17th Jul 2020.

Chen AE, Goldstein M, Carroll K, Song X, Perl TM, Siberry GK. Evolving epidemiology of pediatric Staphylococcus aureus cutaneous infections in a Baltimore hospital. Pediatr. Emerg. Care. 2006; 22:717-723. PMid: 17047471.

Kakar N, Kumar V, Mehta G, Sharma RC, Koranne RV. Clinico‐bacteriological study of pyodermas in children. J. Dermatol. 1999; 26:288-293. PMid: 10380429.

Morrison‐Rodriguez SM, Pacha LA, Patrick JE, Jordan NN. Community‐associated methicillin‐resistant Staphylococcus aureus infections at an army training installation. Epidemiol. Infect. 2010; 138:721-729. PMid: 20096150.

Rogers M, Dorman DC, Gapes M, Ly J. A three‐year study of impetigo in Sydney. Med. J. Aust. 1987; 147:6365. PMid: 3299015.

Szczesiul JM, Shermock KM, Murtaza UI, Siberry GK. No decrease in clindamycin susceptibility despite increased use of clindamycin for pediatric community‐associated methicillin‐resistant Staphylococcus aureus skin infections. Pediatr. Infect. Dis. J. 2007; 26:852-854. PMid: 17721387.

McBride ME, Duncan WC, Knox JM. The environment and the microbial ecology of human skin. Appl. Environ. Microbiol. 1977; 33:603-608. AEM.33.3.603-608.1977. PMid: 16345214, PMCid: PMC170732.

Deotale V, Mendiratta DK, Raut U, Narang P. Inducible clindamycin resistance in Staphylococcus aureus isolated from clinical samples. Indian J. Med. Microbiol. 2010; 28:124-126. PMid: 20404457.

Gadepalli R, Dhawan B, Mohanty S, Kapil A, Das BK, Chaudhry R. Inducible clindamycin resistance in clinical isolates of Staphylococcus aureus. Indian J. Med. Res. 2006; 123:571-573.

Azap OK, Arslan H, Timurkaynak F, Yapar G, Oruc E, Gagir U. Incidence of inducible clindamycin resistance in staphylococci: First results from Turkey. Clin. Microbiol. Infect. 2005; 11:582-584. PMid: 15966979.

Velvizhi G, Sucilathangam G, Palaniappan N. Prevalence and phenotypic detection of erythromycin induced Resistance to clindamycin in MRSA isolates. J. Clin. Diagn. Res. 2011; 5:1195-1198.

Fasih N, Irfan S, Zafar A, Khan E, Hasan R. Inducible clindamycin resistance due to expression of erm genes in Staphylococcus aureus: Report from a tertiary care Hospital Karachi, Pakistan. J. Pak. Med. Assoc. 2010; 60:750-753.

Prabhu K, Rao S, Rao V. Inducible clindamycin resistance in Staphylococcus aureus isolated from clinical samples. J. Lab Physicians. 2011; 3:25-27. PMid:21701659 PMCid:PMC3118052

Angel MR, Balaji V, Prakash JAJ, Brahmadathan KN, Mathews MS. Prevalence of inducible clindamycin resistance in gram positive organisms in a tertiary care centre. Indian J. Med. Microbiol. 2008; 26:262-264. PMid: 18695329.

Mittal V, Kishore S, Siddique ME. Prevalence of inducible clindamycin resistance among clinical isolates of Staphylococcus aureus detected by phenotypic method: A preliminary report. J. Infect. Dis. Immun. 2013; 5:10-12.

Reddy PS, Suresh R. Phenotypic detection of Inducible Clindamycin resistance among the clinical isolates of Staphylococcus aureus by using the lower limit of inter disk space. J. Microbiol. Biotech. Res. 2012; 2:258-264.


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