Antimicrobial Susceptibility Pattern of Bacterial Isolates in Burn Patients in a Tertiary Care Center: A Prospective Study

ABSTRACT

Background: Burn injuries and deaths pose a major public health concern globally, especially in developing and underdevelopedcountries. As burn patients have lost their primary barrier and exposed to microorganism invasion continually and chronically,Staphylococcus aureus becomes one of the greatest causes of nosocomial infection in burn patients though it is a normalskin flora. The cases of antibiotic resistance have increased, and resistant species such as methicillin-resistant S. aureus(MRSA) provide additional challenges in the form of virulence factors. Multimodal infection control concept is required to limitthe spread of infection with multidrug-resistant organism including MRSA in a burn unit. The common pathogens isolated fromburn wounds are S. aureus, Pseudomonas aeruginosa, Streptococcus pyogenes, Acinetobacter baumannii, and various coliformbacilli. Hence, antimicrobial susceptibility pattern of bacterial isolates in burn patients plays a key role in the management ofthese patients.Materials and Methods: This prospective observational study involved the collection of wound swabs from burn patientsfrom June 2018 to May 2019. All patients with burn wounds irrespective of age and sex, admitted through surgery outpatientdepartment or casualty, during the period of study were included in the study.Results: Maximum prevalence was found for P. aeruginosa, i.e., 37.5% followed by S. aureus, for which the prevalencewas found to be 18.75%. The organism least commonly cultured was Acinetobacter; the prevalence of MRSA was found tobe 57.14% and the prevalence of methicillin resistance was found to be 42.8% in patients with Staphylococcus epidermidis.Overall, the prevalence of methicillin resistance was 51.72%. The drugs most effective against P. aeruginosa, the most commonisolate, were meropenem (97.62%) and piperacillin/tazobactam (90.48%) followed by gentamicin (64.29%). Meropenem andpiperacillin/tazobactam showed 100% efficacy against the other Gram-negative bacilli isolated as well. MRSA isolates showed100% sensitivity to vancomycin and linezolid closely followed by piperacillin-tazobactam combination. Klebsiella pneumoniaeshowed 100% sensitivity to meropenem and piperacillin/tazobactam.Conclusions: The overall isolation rate was 75%. Only solitary isolates were studied. Overall, Gram-negative organisms(66.66%) were more common than Gram-positive organisms (33.33%). P. aeruginosa (37.5%) was the most commonisolate followed by S. aureus (18.75%). The prevalence of MRSA was 57.14%, but all the MRSA isolates showed 100%sensitivity to vancomycin and linezolid. On antibiotic sensitivity testing, piperacillin/tazobactam (95.24%) was found to bethe most effective drug against all the organisms isolated. Meropenem (99.40%) was the most effective drug against theGram-negative organisms. Vancomycin (100%) and linezolid (100%) were the most effective drugs for the Gram-positiveorganisms.