[Infections of hip and knee endoprostheses. Spectrum of pathogens and the role of multiresistant bacteria].

BACKGROUND: Because of the rise in primary implantations in elective knee and hip arthroplasty, the number of complications, particularly due to prosthetic infections has increased. Partly due to multimorbidities, an increase in geriatric patients and often unnecessary use of antibiotics, a change in the spectrum of bacteria with an increase in multi-drug resistant pathogens is to be expected. For physicians this creates not only new medical and economic but also sociopolitical challenges.

QUESTION: Has the spectrum of bacteria in prosthetic joint infections after total hip arthroplasty (THA) and total knee arthroplasty (TKA) changed during the 12-year period 2001-2012 in our hospital and what role do multi-drug resistant bacteria play?

INVESTIGATION COLLECTIVE: A total of 320 patients with prosthetic joint infections (PJI) following TKA or THA could be identified and were included in this study. The sample consisted of 172 patients with an infection after THA (56 % females n = 96 and 44 % males n = 76) with a mean age of 70.9 years (range 39-92 years) and 148 patients with an infection after TKA (55 % females n = 82 and 45 % males n = 66) with a mean age of 70.7 years (range 15-87 years). The bacteria detected and the development over the course of time were evaluated.

RESULTS: An increase was found in the occurrence of coagulase negative staphylococci (CNS), in particular Staphylococcus epidermidis (2001-2003 n = 10 and 2010-2012 n = 27). The proportion of oxacillin and methicillin-resistant Staphylococcus epidermidis (MRSE) was also found to increase (0 % in 2001-2003 and 74 % in 2010-2012). A substantial increase in methicillin-resistant Staphylococcus aureus (MRSA) infections could not be found and there was a tendency towards reduction in the total number of Staphylococcus aureus infections. A total of five extended spectrum beta-lactamase (ESBL)-producing bacteria were isolated.

CONCLUSION: The spectrum of bacteria has only slightly changed over the years from 2001 to 2012, whereby an increase was only found in the number of CNS infections. Multi-drug resistant bacteria, in particular MRSE have increased. The changes in MRSE found in this study do not appear to warrant a general rethinking of antibiotic prophylaxis.