Identification, Antibiotic Susceptibility Patterns and Biofilm Detection of Isolates in Orthopaedic Implant Infections

Background: As orthopaedic implants are being increasingly used, managing the implant-associated infections has become a challenge. The aim of this study was to evaluate the bacteriological profile with antibiotic susceptibility patterns and biofilm detection in orthopaedic implant-associated infections.

Study Design: Cross-sectional prospective.

Place and Duration of Study: The study was conducted in the department of Microbiology and Orthopaedics, Sher-i-Kashmir Institute of Medical Sciences (J&K) India, a tertiary care institute from August 2014 to February 2016.

Methods: The study was conducted on 100 patients having orthopaedic implant infections. Demography and patient parameters were recorded. Microbiological workup by microscopy, culture, antimicrobial susceptibility testing and biofilm detection was conducted as well.

Results: 100 cases were analysed out of which 86 cases revealed a positive culture and 14 cases revealed a negative culture. From these culture positive cases, 11 cases were observed as polymicrobial and a total of 97 isolates were recovered. 53 (54.6%) isolates were Gram-positive cocci and 44 (45.4%) were Gram-negative bacilli. The predominant Gram-positive organism observed was Staphylococcus aureus. Among the Gram-negatives, Citrobacter spp. was more prevalent, followed by Acinetobacter spp. 37(38.1%) isolates were found to be multidrug resistant. Gram-positive organisms demonstrated highest susceptibility to Linezolid (100.0%) where as Gram-negative isolates were highly sensitive to Imipenem(88.6%) and Polymyxin-B(93.2%) but showed high resistance towards Cephalosporins. 15.5% of the isolates were strong producers of biofilm. Staphylococcus aureus was the predominant biofilm producer and 57% biofilm producing organisms were multidrug resistant.

Conclusion: Orthopaedic implant–associated infection puts a great financial burden on patients as well as on hospital resources and leads to increased morbidity. Appropriate microbiological interventions will help in reducing the magnitude of the problem.