Bacterial Aetiological Agents in Infected Orthopaedic Implants - A Cross Sectional Study from Andhra Medical College, Visakhapatnam


Sulakshana Sony Cheemala1, Rama Lakshmi Koripella2, Bala Murali Krishna Perala3

Orthopaedic implant site infection is one of the major problems of surgical site
infection associated with high morbidity and mortality. As implants are commonly
used in orthopaedic procedures and especially when preceded by trauma,
orthopaedic procedures are more prone for surgical site infections. We wanted to
study the aerobic bacterial aetiology of infected orthopaedic implants.
This was a cross sectional study carried out over a period of one and half years.
The study group comprised of 100 patients who had undergone orthopaedic
prosthetic implant surgeries and presented with signs and symptoms of infections.
The demographic data were recorded, type of surgery, the time of infection during
postoperative period and risk factors were noted. Serous / purulent discharge
adjacent to infected implants were processed in the laboratory as per the standard
Among the 100 samples studied, 79 % were culture positive and 21 % culture
sterile. 55.7 % were Gram-positive cocci isolated in pure, 29.1 % were Gramnegative
bacilli (GNB) isolated in pure and 15.2 % were a mixture of Gram-positive
cocci and Gram-negative bacilli. Staphylococcus aureus 45 (80.4 %) was the
predominant isolate followed by Coagulase Negative staphylococci 11(19.6 %).
Among the GNB (35), the predominant isolate was Pseudomonas aeruginosa 10
(28.6 %) followed by Klebsiella pneumoniae 8 (22.9 %). Infections occurred
during the early post-operative period in 63 % cases. Methicillin resistant
Staphylococcus aureus were 53.4 % and 35 % were extended spectrum beta
lactamases (ESBL) among Enterobacteriaceae strains.
Orthopaedic implant site infections are common during early post-operative
period. Methicillin resistant staphylococcus and ESBL strains were high. This study
of aerobic bacterial analysis and their current antibiogram of orthopaedic implant
infections would greatly help the orthopaedic surgeons in selecting appropriate
antibiotics for prophylaxis as well as better management of patients.