Antibiotic resistance profiles of deep surgical site infections in hip hemiarthroplasty; comparing low dose single antibiotic versus high dose dual antibiotic impregnated cement

Abstract

Objectives: The incidence of fractured neck of femur (FNOF) is increasing yearly. Many of these patients undergo hip hemiarthroplasty. High dose dual-antibiotic cement (HDDAC) has been shown to reduce rates of deep surgical site infection (SSI) when compared to the current standard low dose single-antibiotic cement (LDSAC) in a quasi-randomised controlled trial. Some concerns exist regarding the use of HDDAC and the development of antibiotic resistance. We reviewed cases of infection in LDSAC and HDDAC bone cement with regard to causative organism and resistance profile.Methods: A retrospective analysis was undertaken of all hemiarthroplasties within our trust from April 2008 to December 2014. We identified all patients in this time period who acquired a deep SSI. The infecting organisms and susceptibility patterns were collated for each cement.Results: We identified 1941 hemiarthroplasties. There were 38 deep surgical site infections representing an infection rate of 3.4% in LDSAC patients and 1.2% in HDDAC patients. The majority of infections were polymicrobial. Staphylococcus epidermidis was the most commonly isolated organism. It accounted for a larger proportion of HDDAC than LDSAC infections (p<0.05). Infection with Corynebacterium species and S. aureus, including MRSA, was eradicated completely with the use of HDDAC. There was no significant change in the proportion of Gram negative and Gram positive infections between the two cements. In Gram positive organisms, there was no significant change in resistance to most antibiotics. Although fewer resistant infections overall, there were significant increases in the proportion of resistance to ciprofloxacin and clindamycin with HDDAC. We observed no resistance to daptomycin or linezolid in either cement and levels of resistance remained low to rifampicin and teicoplanin. In Gram negative organisms, no significant change in resistance was observed.Conclusions: We observed a significantly lower infection rate with the use of HDDAC compared to LDSAC. Such was this reduced infection rate that there was a trend to a lower rate of resistance with the use of HDDAC. However, there were increases in the proportion of resistant cases, most notably to clindamycin and ciprofloxacin in Gram positive organisms, possibly reflecting the higher number of S. epidermidis in the HDDAC group. Whilst the differences in our study were not found to be statistically significant, it is reassuring for teams using HDDAC to prevent SSI in hip hemiarthroplasty.

Antibiotics and cement: what I need to know?

“…21,22 Of most clinical importance was the recent finding that bacteria found in PJI -even if resistant to gentamicin -did not show cross-resistancies to other antibiotics commonly used for antibiotic treatment. 23 Resistance patterns in Nordic countries…”

Risk assessment of antibiotic resistance development by antibiotic-loaded bone cements: is it a clinical concern?

“…In a very recent analysis within a large clinical trial designed to compare the infection rates in neck-of-femur fracture patients as a function of the antibiotic-loaded bone cement used for the fixation of the hemiprosthesis, Tyas et al reviewed the cases of deep surgical site infections with regard to the causative pathogens and their antibiotic resistance profiles. 39 It was found that the reduction in deep infection cases was such in patients receiving a high dose antibiotic-loaded cement (HDAC) (infection rate: 1.2% in HDAC group = bone cement with 1 g gentamicin and 1 g clindamycin) as compared with a low dose antibiotic cement (LDAC) (infection rate: 3.4% in LDAC group = bone cement with 0.5 g gentamicin; p = 0.003) that there was a trend towards a lower rate of resistance with the use of HDAC. The authors therefore concluded that the concomitant prophylactic use of two antibiotics in the cement did not drive antibiotic resistant infections (see Table 2).…”

A randomized clinical trial of low dose single antibiotic-loaded cement versus high dose dual antibiotic-loaded cement in patients receiving a hip hemiarthroplasty after fracture: A protocol for the WHiTE 8 COPAL study

“… 18 The concern with widespread use of high dose dual ALBC is increased cost, and the risk of increased antibiotic resistant periprosthetic joint infections, although published data on the later appears reassuring. 16 There is also a theoretical risk of systemic toxicity, though there is little to no compelling data supporting this concern. 19 …”