Beta lactamases mediated resistance amongst gram negative bacilli in burn infection

Authors:Nitin Bandekar , Vinodkumar CS, Basavarajappa KG, Prabhakar PJ, Nagaraj P
Int J Biol Med Res. 2011; 2(3): 766-770  |  PDF File


Introduction: Burn is one of the most common and devastating forms of trauma. Patients with serious thermal injury require immediate specialized care in order to minimize morbidity and mortality. Significant thermal injuries induce a state of Immuno- suppression, which predisposes infectious complications in burn patients. In burn patient infections arise from multiple sources and infect burn wounds by a variety of micro-organisms. Gram negative bacterial infection results from translocation from colon, further more burn patients are infected by Hospital acquired bacteria by various invasive and non invasive procedures Early diagnosis of microbial infections and screening for mechanism of drug resistance is aimed to institute the appropriate antibacterial therapy and to avoid further complications. Objectives: Beta lactamases are enzymes responsible for the resistance to beta lactam antibiotics. This study is aimed at the detection of various types of beta lactamases present among the gram negative bacilli isolated from burn infection. Methods: patients admitted to burn intensive care unit were included in the study.83 gram negative bacilli were isolated and screened for the presence of extended spectrum beta lactamase, AmpC lactamase, Metallo beta lactamase and confirmed by the respective confirmatory tests. Results: 39.8% produced extended spectrum beta lactamases, 22.9% AmpC beta lactamase and 15.7% strains produced metallo beta lactamases. Pseudomonas aeruginosa was the predominant bacteria producing ESBL and AmpC mediated resistance, whereas Acinetobacter baumannii was the predominant MBL producer. Conclusion: It is important to monitor the bacteriology in burn patients at all time, and understand the changing pattern of bacterial flora, antibiotic susceptibility and bacterial strains spreading in burn ward. Extended-spectrum beta-lactamases is the cause of resistance. After sulbactam added to the third generation of cephalosporins, the beta-lactamases were inhibited, but it lead to increase use of carbapenems leading to emergence of metallo beta lactamase mediated resistance. Hence, screening techniques should be performed routinely to detect these β-lactamase producers so that suitable antimicrobial therapy can be instituted