No changes in the distribution of organisms responsible for septic arthritis over a 20 year period

Objective: To assess changes in the distribution and resistance of the pathogens responsible for septic arthritis over a 20 year period in patients admitted to the same hospital unit. Patients and methods: Retrospective study of the hospital records of patients admitted between 1979 and 1998 for septic arthritis with positive microbiological diagnosis after blood or joint cultures, or both. Results: 303 cases of septic arthritis were studied, 141 in the period 1979-88 and 162 in the period 1989-98. The incidence between the first and second period did not vary significantly for the staphylococci (67% v 63%), streptococci (16% v 20%), and Gram negative bacilli (7% v 10%). Tuberculous infections decreased from 9% to 4% (p<0.04). No gonococci were isolated in the second 10 year period. Among the staphylococcal species, there was an increase in the number of coagulase negative staphylococci (10 cases v 21, p<0.05) between the two periods. There was no significant difference in the frequency of occurrence of methicillin resistant pathogens (12.6% v 16.6%). The number of streptococcal B infections increased (2 v 10 cases), and (beta-lactamine resistant pneumococci emerged. In the second 10 year period, patients were older and were more likely to have co-existing disease, particularly tumoral growth, and less commonly were receiving dialysis. Localisation of joint infection was comparable except for an increase in prosthetic knee infections. Conclusion: The distribution and sensitivity of pathogens causing septic arthritis changed little over a 20 year period.