Shobha Medegar

Background: Biofilms are defined as microbially derived sessile communities characterized by the cells that are irreversibly attached to a substratum. These organisms have been associated with implant associated infections Aims: The present study is therefore undertaken 1. To compare the three screening methods used for detection of biofilm formation (Tissue culture plate method, Tube method and Congo red agar method) and 2. To correlate the antibiotic resistance pattern of biofilm producers and non biofilm producers. Materials and Methods : A prospective study was carried out in the department of microbiology, on all orthopedic implant associated infections from September 2015 to July 2016 on aspirated pus samples. A total of 120 non repetitive clinical isolates were taken and subjected to biofilm detection. All the bacterial isolates were identified by standard biochemical tests. Antibiotic susceptibility test of bacterial isolates was performed by Kirby Bauer disk diffusion method according to Clinical Laboratory Standard Institute (CLSI) guidelines on Muller Hinton Agar (MHA). A reference strain of Staphylococcus epidermidis ATCC 35984(positive biofilm producer) and Staphylococcus epidermidis ATCC 12228(non biofilm producer) were used as controls. Results: Tissue culture plate method was considered as gold standard as it detected 25% biofilm producers which included 12% weak biofilm producers which was missed by congo red agar (CRA) and tube method (TM). Also, this correlated to methicillin resistant staphylococcus aureus (MRSA), ESBL, amp-c and MDR pattern of antibiogram. Conclusion : TCP is considered as most reliable screening method for biofilm detection and should be routinely employed to prevent treatment failures as these organisms are intrinsically resistant to many antimicrobials leading to implant associated infections.   Keywords: Antibiogram, Biofilm, Implant, Tissue culture plate method

Introduction: Body fluids like pleural fluid, ascitic fluid, cerebrospinal fluid etc are usually sterile, but they can get infected by different micro organisms, thus leading to life threatening infections.1,2 Aims and Objectives: 1) To isolate the causative organisms of sterile body fluid infections. 2) To determine the antimicrobial resistance pattern of the isolates. Materials and Methods: 1) This is a retrospective observational study, conducted from January 2017 to December 2017 in the department of Microbiology KIMS Hubli. 2) Sterile body fluids were processed according to Standard laboratory Procedures. 3) Antimicrobial susceptibility testing was performed by Kirby-Bauer disc diffusion method as per CLSI guidelines. Results: A total of 635 samples were studied out of which 233(36.6%) were pleural fluids, 222(34.9%) were ascitic fluids, 174(27.4%) were cerebrospinal fluids and 06(0.9%) were pericardial fluid. In our study the predominant organisms were E-coli (23.23%) and NFGNB (19.01%) followed by Pseudomonas (14.08%), Klebsiellaspp (13.38%), S.aureus (10.56%) and Citrobacter spp (7.04%). Gram negative isolates were 100% sensitive to Imipenem followed by Amikacin (78%), Gentamicin (74%), Cefepime (69%). The Gram positive isolates were 100% sensitive to Vancomycin and Linezolid followed by Gentamicin (96%), Cefepime (94%), Amikacin (92%). The Pseudomonas isolates were highly sensitive to Imipenem (96%) and Piperacillin Tazobactum (92%). High resistance was observed to Ceftazidime, Cefoperazone and Levofloxacin. Conclusion: Knowledge of bacteriological and antimicrobial profile of sterile body fluids is necessary, so that the life threatening infections can be effectively treated and thus to prevent antimicrobial resistance associated with it. Keywords: Sterile Body fluids, Antimicrobial resistance, E-coli, NFGNB, Kirby-Bauer disk diffusion method.