Staph aureus is gram positive cocci, which are arranged in grapes like clusters. Staph aureus is commonly found on the skin. Staph aureus is an aerobic and facultative anaerobic organism. They produce yellow and white colour colonies on nutrient agar media.Staph aureus causes superficial and deep infections.1 Staph aureus is the common cause of nosocomial infections, surgical wound infections and bacteremia (bacteremia means bacteria present in the blood). 2 Aggregation of dead leucocytes and pyogenic bacteria is commonly known as PUS, “a yellow to white fluid”.3 Pus is formed due to injury caused by outside forces such as surgical wounds, burns, slight cuts, gunshot and after surgery.4 Staph aureus is mostly found in pus samples.
Minor cut of the skin will allow the bacteria present on the surface to enter the body and start multiplication locally. Immune cells fight against the bacteria. 5 The isolated aerobes were identified as gram positive bacteria such asStaph aureus, Staph epidermidisand gram negative bacteria likeE coli, Klebsiella pneumoniae. 6 Pus is a thick fluid that can be generated by many organisms.7 Staph aureus is a important pathogen that creates problems for clinicians in the treatment of infections caused by an increase resistance to penicillin then now to oxacillin that means MRSA (Methicillin Resistant Staphylococcus aureus) also resistance other group of antibiotics like Linezolid, Vancomycin. 8 There are 12 variant genes have identified Van A-E, G, H, L, M, N, R and X. 9
Materials and Methods
This study was done on the patients attending Teerthanker Mahaveer Hospital and Research Centre (TMH & RC) Moradabad, UP, India, from December 2019 - October 2020. In this study patients of all the age groups (Except paediatric age) both male and female visiting in the Teerthanker Mahaveer Hospital were included and the pus samples were received from central laboratory of Microbiology Department for the microscopy, gram staining, manual culture and antibiotic susceptibility test. Total 158 isolates were of Staph aureus had been taken from the pus samples.
Detection of MRSA
All isolated microorganisms were screened for methicillin resistance using Cefoxitin disk (30mcg) and the plates were incubated for 24 hours at 350C as per CLSI guidelines. For the zone of inhibition the petri plates were examined in reflected light on a non-reflected backdrop. According to CLSI guidelines isolated organism demonstrating an inhibition zone of inhibition of <14 mm were considered MRSA. 10
Detection of VRSA
All isolated microorganisms were screened for Vancomycin resistance using Vancomycin disk (30mcg) and the plates were incubated at 350C for 24 hours as CLSI guidelines. For the zone of inhibition the petri plates were examined in reflected light on a non- reflected backdrop. Isolated organism demonstrating an inhibition of <17 mm were considered VRSA according to CLSI guidelines. 10
In this study total 320 pus samples were included, out of which 158 samples were found positive for Staph aureus, after that antibiotic sensitivity testing was done for 158 Staph aureus isolates.
Out of 158 Patients included, 102 (64.6%) were males and 56 (35.4%) were females. Out of 158 clinically diagnosed Staphylococcus aureus males were more in number than to females.Table 1
Total 158 Staph aureus were isolated, out of which maximum numbers of Staph aureus were obtained from Surgery 67 (42.4%), followed by Orthopedics 36 (22.7%), Medicine 22 (13.9%), ENT 16 (10.1%), ICU 12 (7.5%) and least from Dermatology 5 (3.1%).
Out of 158 Staph aureus were isolated, 92 (58.2%) were Methicillin Sensitive Staph aureus (MSSA) and 66 (41.7%) were Methicillin Resistance Staph aureus (MRSA).Figure 1
Out of 158 Staph aureus were isolated, 154 (97.4%) were Vancomycin Sensitive Staph aureus (VSSA) and 4 (2.5%) were Vancomycin Resistance Staph aureus (VRSA).Figure 2
In both community and hospital acquired infections, Staph aureus is one of the most frequently isolated pathogens. MRSA is a methicillin- resistant strain of the bacterium Staph aureus. In our study, Out of 158 pus samples, 102 (64.6%) Staph aureus were isolated from males and 56 (35.4%) from females. On comparison our present study with the previous study that have been done in different areas of the country. In similar to this study Devi U S et al4 in 2017 there were 59 Staph aureus isolated 38 (64.4%) were males and 21 (35.5%) were females.
In our present study, the maximum number of Staph aureus were found in Surgery ward 67 (42.4%), where as 36 (22.7%) Staph aureus were found in Orthopedics, 22 (13.9%) were found in Medicine, 16 (10.1%) were found in ENT, 12 (7.5%) were found in ICU and 5 (3.1%) were found in Dermatology. A study done by Banker N et al, 2 the maximum number of Staph aureus were found in General Surgery 207 (68.09%), followed by Orthopedics 31 (10.20%), Medicine 19 (6.25%), ENT 11 (3.62%) and Dermatology 5 (1.64%)In our study, out of 158 Staph aureus were isolated, 66 (41.7%) were MRSA and 4 (2.5%) were VRSA. MRSA were detected by their sensitivity to Cefoxitin/Oxacillin as performed according to CLSI guidelines. Prevalence of MRSA in previous study by Harshan K H et al, 11 Banker N et al 2 and Devi U et al 4 were 29.7%, 28.8% and 26.9%.A study of Banker N et al 2 showed only 1.9% isolates were resistance to Vancomycin. While in our study 2.5% isolated were resistance to Vancomycin.Harshan H K et al 11 in a study reported a high level resistance to Penicillin (97.5%), followed by Erythromycin (46.3%) and Gentamycin (29.7%). Staph aureus isolated showed high resistance to Penicillin (92.4%) followed by Amoxycillin (88.6%), Ampicillin (87.9%), Norfloxacin (86.7%), Erythromycin (57.7%) and Cefoxitin/Oxacillin (41.7%) and Teicoplanin (23.4%) in our research. And most of the Staph aureus isolated showed higher sensitivity to Vancomycin (97.4%), Linezolid (93.6%), Doxycyclin (92.4%), Rifampicin (85.4%), and Clindamycin (70.8%) and Amikacin (67.0%).
Emergence of MRSA and VRSA infections is a growing problem in our hospital. Our research shows that antibiotics sensitivity patterns of isolated Staph aureus can help in formulating the hospital antibiotic policy. Accurate treatment helps to reduce the rate of morbidity and improvement of patient’s outcome. An antibiotic policy and screening of susceptibility patterns of MRSA may also help in reducing the prevalence rate of MRSA and antibiotic resistance. Infections that are caused by MRSA, Vancomycin is the most effective drug and to protect its value for the long life infections, the use of Vancomycin as first choice of treatment should be avoided. The tolerance of Teicoplanin, Linezolid and Doxycyclin to MRSA shows low resistance, so they may be useful in the treatment of staph infections.
Source of Funding
The authors declare that we have received no financial support for the research, authorship, and/or publication of this article.