IDENTIFICATION OF GRAM-POSITIVE AND GRAM-NEGATIVE BACTERIA IN POST-SURGICAL PATIENTS AND THEIR ANTIBIOTIC SENSITIVITY PATTERN
DOI:
https://doi.org/10.71000/evm69y14Keywords:
Staphylococcus aureus, surgical site infections, antibiotic resistance, Escherichia coli, Gram-negative bacteria, Gram-positive bacteria, Vancomycin.Abstract
Background: Surgical site infections (SSIs) continue to be a major postoperative complication, particularly in resource-limited healthcare settings. These infections significantly prolong hospitalization, increase morbidity, and escalate healthcare costs. Both Gram-positive and Gram-negative bacteria are implicated, and the rise of antimicrobial resistance has further complicated management. Accurate identification of pathogens and their resistance patterns is essential to guide empirical therapy and strengthen infection control practices.
Objective: To identify Gram-positive and Gram-negative bacteria isolated from post-surgical patients and to evaluate their antimicrobial susceptibility patterns.
Methods: A descriptive cross-sectional study was conducted in the Department of Microbiology, Arif Memorial Teaching Hospital, Lahore, from August 2024 to January 2025. A total of 104 clinical specimens, including pus, wound swabs, and blood samples, were collected using convenient sampling. Standard microbiological procedures such as Gram staining, colony morphology, catalase, coagulase, and biochemical assays were employed for bacterial identification. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method in accordance with CLSI 2018 guidelines. Data were analyzed using SPSS version 25, with frequencies and percentages calculated for isolates and resistance profiles.
Results: Out of 104 collected specimens, 63 (60.6%) were culture-positive, while 41 (39.4%) showed no growth. Staphylococcus aureus was the predominant pathogen (23.1%), followed by Escherichia coli (19.2%), Enterobacter species (7.7%), Staphylococcus species (3.8%), Pseudomonas (1.9%), Proteus vulgaris (1.9%), and Klebsiella species (1.9%). Gram-positive isolates showed complete resistance to penicillin and ampicillin (100%) but full sensitivity to vancomycin (100%) and high sensitivity to linezolid (81.8%). Gram-negative isolates exhibited marked resistance to ceftazidime (96.0%), ciprofloxacin (82.4%), and levofloxacin (82.5%), whereas carbapenems such as imipenem (80.0%) and meropenem (74.3%) retained considerable efficacy.
Conclusion: The findings highlight the coexistence of Gram-positive and Gram-negative organisms as major contributors to SSIs, with alarmingly high resistance to first-line antibiotics. Vancomycin, linezolid, and carbapenems remain effective therapeutic options. The results emphasize the urgent need for continuous surveillance, rational antimicrobial use, and stronger infection control strategies to reduce SSI-related morbidity.
References
Misha G, Chelkeba L, Melaku T. Bacterial profile and antimicrobial susceptibility patterns of isolates among patients diagnosed with surgical site infection at a tertiary teaching hospital in Ethiopia: a prospective cohort study. Ann Clin Microbiol Antimicrob. 2021 Dec 1;20(1).
Maharjan N, Mahawal BS. Bacteriological Profile of Wound Infection and Antibiotic Susceptibility Pattern of Various Isolates in a Tertiary Care Center. Journal of Lumbini Medical College [Internet]. 2020 Oct 29;8(2):218–24.
Chelkeba L, Melaku T, Mega TA. Gram-negative bacteria isolates and their antibiotic- resistance patterns in patients with wound infection in Ethiopia: A systematic review and meta-analysis. Vol. 14, Infection and Drug Resistance. Dove Medical Press Ltd; 2021. p. 277–302.
Shakir A, Abate D, Tebeje F, Weledegebreal F. Magnitude of surgical site infections, bacterial etiologies, associated factors and antimicrobial susceptibility patterns of isolates among post-operative patients in harari region public hospitals, harar, eastern Ethiopia. Infect Drug Resist. 2021;14:4629–39.
Behera HS, Chayani N, Bal M, Khuntia HK, Pati S, Das S, et al. Identification of population of bacteria from culture negative surgical site infection patients using molecular tool. BMC Surg. 2021 Dec 1;21(1).
Al-Said H, Alghamdi A, Ashgar S, Jalal N, Faidah H, Johargy A, et al. Isolation and detection of drug-resistant bacterial pathogens in postoperative wound infections at a tertiary care hospital in Saudi Arabia. Saudi J Med Med Sci. 2023 Sep 1;11(3):229–34.
Abayneh M, Asnake M, Muleta D, Simieneh A. Assessment of Bacterial Profiles and Antimicrobial Susceptibility Pattern of Isolates Among Patients Diagnosed with Surgical Site Infections at Mizan-Tepi University Teaching Hospital, Southwest Ethiopia: A Prospective Observational Cohort Study. Infect Drug Resist. 2022;15:1807–19.
Narula H, Chikara G, Gupta P. A prospective study on bacteriological profile and antibiogram of postoperative wound infections in a tertiary care hospital in Western Rajasthan. J Family Med Prim Care. 2020;9(4):1927.
Thakur N, Kujur A. Microbiological and antibiotic sensitivity pattern of surgical site infection following caesarean section in a tertiary care center of Chhattisgarh. Int J Reprod Contracept Obstet Gynecol. 2021 Jun 28;10(7):2638.
Abayneh M, Asnake M, Muleta D, Simieneh A. Assessment of Bacterial Profiles and Antimicrobial Susceptibility Pattern of Isolates Among Patients Diagnosed with Surgical Site Infections at Mizan-Tepi University Teaching Hospital, Southwest Ethiopia: A Prospective Observational Cohort Study. Infect Drug Resist. 2022;15:1807–19.
Bediako-Bowan AAA, Kurtzhals JAL, Mølbak K, Labi AK, Owusu E, Newman MJ. High rates of multi-drug resistant gram-negative organisms associated with surgical site infections in a teaching hospital in Ghana. BMC Infect Dis. 2020 Dec 1;20(1).
Fahim NAE. Prevalence and antimicrobial susceptibility profile of multidrug-resistant bacteria among intensive care units patients at Ain Shams University Hospitals in Egypt— a retrospective study. Journal of the Egyptian Public Health Association. 2021 Dec 1;96(1).
Jha B, Gautam S, Sharma J, Sharma M. Bacteriological Profile and Antimicrobial Resistance Pattern in Surgical Site Infection in a Tertiary Care Hospital, Central Nepal. Medical Journal of Shree Birendra Hospital. 2021 Sep 6;20(2):110–5.
Jibu RM, Geetha R V., Lakshmi T. Isolation, Detection and Molecular Characterization of Staphylococcus aureus from Postoperative Infections. J Pharm Res Int. 2020 Aug 24;63–7.
Chelkeba L, Melaku T, Mega TA. Gram-negative bacteria isolates and their antibiotic- resistance patterns in patients with wound infection in Ethiopia: A systematic review and meta-analysis. Vol. 14, Infection and Drug Resistance. Dove Medical Press Ltd; 2021. p. 277–302.
Alam MM, Islam MN, Hossain Hawlader MD, Ahmed S, Wahab A, Islam M, et al. Prevalence of multidrug resistance bacterial isolates from infected wound patients in Dhaka, Bangladesh: A cross-sectional study. International Journal of Surgery Open. 2021 Jan 1;28:56–62.
Nouri F, Karami P, Zarei O, Kosari F, Alikhani MY, Zandkarimi E, et al. Prevalence of common nosocomial infections and evaluation of antibiotic resistance patterns in patients with secondary infections in Hamadan, Iran. Infect Drug Resist. 2020;13:2365–74.
Shah S, Singhal T, Naik R, Thakkar P. Predominance of multidrug-resistant Gram-negative organisms as cause of surgical site infections at a private tertiary care hospital in Mumbai, India. Indian J Med Microbiol. 2020 Jul 1;38(3–4):344–50.
Waheed F, Khan AS, Babar U, Khan MS. SURGICAL SITE INFECTION WITH EXTREME DRUG-RESISTANT ACINETOBACTER BAUMANII: A WAKE-UP CALL! J Ayub Med Coll Abbottabad. 2024;36(2):430-2.
Abbas S, Yasmin A, Kazmi A. Uncovering the genetic arsenal of a multidrug-resistant Escherichiacoli MB641 strain from infected orthopaedic implants in a hospital setting. Microb Pathog. 2025;207:107854.
Hassan B, Ijaz M, Khan A, Sands K, Serfas GI, Clayfield L, et al. A role for arthropods as vectors of multidrug-resistant Enterobacterales in surgical site infections from South Asia. Nat Microbiol. 2021;6(10):1259-70.
Abbas S, Yasmin A, Maqbool N, Shah AA, Fariq A. Insights into the microbiological and virulence characteristics of bacteria in orthopaedic implant infections: A study from Pakistan. PLoS One. 2023;18(10):e0292956.
Downloads
Published
Issue
Section
License
Copyright (c) 2025 Uswa Nawaz, Neelam Fatima, Shabana Nawaz, Hafiz Asif Muhammad Ali, Areesha Akram, Anas Jahangir (Author)
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
