Perioperative Antibiotic Prophylaxis Has No Effect on Time to Positivity and Proportion of Positive Samples: a Cohort Study of 64 Cutibacterium acnes Bone and Joint Infections

Abstract

If a bone or joint infection is suspected, perioperative antibiotic prophylaxis is frequently withheld until intraoperative microbiological sampling has been performed. This practice builds upon the hypothesis that perioperative antibiotics could render culture results negative and thus impede tailored antibiotic treatment of infections. We aimed to assess the influence of antibiotic prophylaxis within 30 to 60 min before surgery on time to positivity of microbiological samples and on proportion of positive samples in Cutibacterium acnes bone and joint infections. Patients with at least one sample positive for C. acnes between January 2005 and December 2015 were included and classified as having an "infection" if at least 2 samples were positive; otherwise they were considered to have a sample "contamination." Kaplan-Meier curves were used to illustrate time to culture positivity. We found 64 cases with a C. acnes infection and 46 classified as having a C. acnes contamination. Application of perioperative prophylaxis significantly differed between the infection and contamination groups (72.8% versus 55.8%; P < 0.001). Within the infection group, we found no difference in time to positivity between those who had or had not received a perioperative prophylaxis (7.07 days; 95% confidence interval [CI], 6.4 to 7.7, versus 7.11 days; 95% CI, 6.8 to 7.5; P = 0.3). Also, there was no association between the proportion of sample positivity and the application of perioperative prophylaxis (71.6% versus 65.9%; P = 0.39). Since perioperative prophylaxis did not negatively influence the microbiological yield in C. acnes infections, antibiotic prophylaxis can be routinely given to avoid surgical site infections.

Keywords: Cutibacterium acnes; Propionibacterium acnes; biofilm; intraoperative diagnostic; joint infection; osteomyelitis; perioperative antibiotic prophylaxis.

FIG 1

Distribution of infection and preoperative prophylaxis status among patients and samples. A total of 68.8% of the patients in the infection group did not receive antibiotic prophylaxis, compared to 50% of patients in the contamination group. AB, antibiotic.

FIG 2

(A) Kaplan-Meier curve illustrating the proportion of sample positivity with C. acnes in all 274 positive samples, stratified by infection status (228 in the infection group versus 46 in the contamination group). The median time to positivity was 6 days for the infection group and 9 days for the contamination group (log rank P < 0.001). The colored areas represent the 95% confidence interval. (B) Kaplan-Meier curve illustrating the proportion of sample positivity with C. acnes in the 342 samples of the infection group, stratified by preoperative prophylaxis (93 in the prophylaxis group versus 249 in the no prophylaxis group). The median time to positivity was 8 days for the prophylaxis group and 7 days for the no prophylaxis group (log rank P = 0.3). The colored areas represent the 95% confidence interval. AB, antibiotic; periop, perioperative.