Surgical site infection(SSI) is major problem in in clinical aspects instead of technical advances in infection control and surgical practices[1]. SSI as infection occurring within 30 days or in some specific surgeries 90 days after a surgical operation[2].  SSI causes increase in the treatment cost, length of hospital stay and significant morbidity and mortality[3]. SSI can be caused by increasing prevalence of some multi drug resistant gram positive organisms like Methicillin resistant Staphylococcus aureus (MRSA), Coagulase Negative Staphylococci, Vancomycin Resistant Enterococci (VRE). The aim of the study is to evaluate the occurrence of SSI, associated with gram positive microorganisms and their drug sensitivity pattern at our tertiary care centre.

This was a descriptive (Cross-sectional) study conducted in the Department of Microbiology at a tertiary care centre in Central India  from November 2020 to December 2022 with approval from institute ethical committee and informed consent was obtained from the subjects.

A total of 241 samples were collected from SSI cases with complaint of pain, swelling, redness, discharge, delayed or non-healing wound and processed as per standard microbiological techniques[4]. Antimicrobial susceptibility testing was performed as per CLSI 2020[5].

Out of 220 culture positive samples; 175 showed monomicrobial growth and 45 showed polymicrobial growth. Among SSI cases with each polymicrobial growth, two isolates were grown in culture positive samples.

Out of 265 isolates most common isolated gram positive  organism was Staphylococcus aureus 36(13.59%) followed by CoNS 12(4.53%) and Enterococcus faecalis 5(1.89%) and others were gram negative organisms.

All the 36 Staphylococcus aureus isolates were sensitive to Vancomycin and Linezolid. Maximum resistance was shown towards Penicillin i.e. 31(86.11%) (Table1).

Among 12 isolates of CoNS, all the isolates were found to be sensitive to Vancomycin and Linezolid. 10(83.33%) isolates were resistant to Penicillin and 2(16.67%) isolates were found to be resistant to Clindamycin.(Table 1)

12 (33.33%) S. aureus isolates were found to be resistant to Methicillin while among 12 CoNS isolates, 2(16.67%) were Methicillin resistant. Among 18 S. aureus isolates;9(25%) isolates had shown Inducible Clindamycin resistance. (Table 2)

Table 1: Antimicrobial resistance in Staphylococcus species

*Sensitivity by MIC(E-test) method

Table 2: Methicillin resistant and Inducible Clindamycin resistant in Staphylococcal species:

Out of 220 culture positive samples, 175 showed monomicrobial growth and 45 showed polymicrobial growth. Among SSI cases with each polymicrobial growth, two isolates were grown in culture positive samples.

Out of total 265 isolated organisms from culture positive SSI cases, most common gram positive organism isolated was S. aureus (13.59%). Similar finding were reported by Dessie et al[6]  22.4% and Mehta et al [7]  27.84% in their studies.

Coagulase negative staphylococci was isolated in 4.53% culture positive SSIs cases. This is comparable to the study by Dessie et al2[6] who reported 8.2% and Verma et al[8] reported 3.48%.

Among 36 isolates of S.aureus, all the isolates were found to be sensitive to Vancomycin and Linezolid, while 86.11% of Staphylococcal isolates were resistant to Penicillin. Similar results for 100% sensitivity to Vancomycin and Linezolid have been published by multiple studies like Siddiqui et al, [11] and Narula et al[12].

In present study, all the 12 isolates of Coagulase negative staphylococci (CoNS) were found sensitive to Vancomycin and Linezolid while 16.67% isolates were resistant to Clindamycin and Cefoxitin both respectively. It is comparable to Budhani et al[13] that shows 97.8% CoNS were sensitive to Linezolid followed by Vancomycin (96.8%), and Gentamicin (85.6%) while 40.5% isolates were resistant to Cefoxitin.

Percentage of MRSA in  present study is 12 (33.33%). Among CoNS, two(16.67%) were detected as MRCoNS. It was found that all the methicillin resistant strains (100%) were sensitive to Vancomycin and Linezolid comparable with studies by Jain et al [14] who reported 48.78% and Negi et al[1]  reported 15.7% of MRSA in their study.

In present study, 9(25%) isolates of S. aureus isolates were detected as ICR  while a study by Eksi et al[15] detected in 6.9%  MRSA strains and Mokta et al[16] reported ICR 28.39%,

Most of the pathogens associated with the SSIs among gram positive organisms in the study is S. aureus. Among these, 33.33% are MRSA which showed multidrug resistance pattern and 25% were inducible Clindamycin resistant. These isolates were showing least resistance pattern toward Vancomycin and linezolid while Maximum resistance was shown towards Penicillin i.e. 31(86.11%) while 12 (33.33%) isolates were found to be resistant to Cefoxitin. Reduction in  SSI  infection rate reduces  the wastage of healthcare resources, patient morbidity and mortality. This would be supported with proper infection control measures and  antibiotic policy. Infection by Multidrug-resistant bacteria enhances the need for antibiotic stewardship policy in hospitals.

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