Osmon, Douglas R.

Abstract In this cohort of 51 patients managed with retained “destination spacers” after the resection of infected joint prostheses, the presence of preoperative sinus drainage was significantly associated with reinfection. Chronic antimicrobial suppression after destination-spacer retention did not significantly prevent reinfections.

ABSTRACT We have previously demonstrated that culturing periprosthetic tissue in blood culture bottles (BCBs) improves sensitivity compared to conventional agar and broth culture methods for diagnosis of prosthetic joint infection (PJI). We have also shown that prosthesis sonication culture improves sensitivity compared to periprosthetic tissue culture using conventional agar and broth methods. The purpose of this study was to compare the diagnostic accuracy of tissue culture in BCBs (subsequently referred to as tissue culture) to prosthesis sonication culture (subsequently referred to as sonicate fluid culture). We studied 229 subjects who underwent arthroplasty revision or resection surgery between March 2016 and October 2017 at Mayo Clinic in Rochester, Minnesota. Using the Infectious Diseases Society of America (IDSA) PJI diagnostic criteria (omitting culture criteria) as the gold standard, the sensitivity of tissue culture was similar to that of the sonicate fluid culture (66.4% versus 73.1%, P = 0.07) but was significantly lower than that of the two tests combined (66.4% versus 76.9%, P < 0.001). Using Bayesian latent class modeling, which assumes no gold standard for PJI diagnosis, the sensitivity of tissue culture was slightly lower than that of sonicate fluid culture (86.3% versus 88.7%) and much lower than that of the two tests combined (86.3% versus 99.1%). In conclusion, tissue culture in BCBs reached sensitivity similar to that of prosthesis sonicate fluid culture for diagnosis of PJI, but the two tests combined had the highest sensitivity without compromising specificity. The combination of tissue culture in BCBs and sonicate fluid culture is recommended to achieve the highest level of microbiological diagnosis of PJI.

Abstract Background Chronic Coxiella burnetii infections such as vertebral osteomyelitis caused by contiguous spread from an infected abdominal aortic graft or aneurysm have been rarely reported and are associated with significant morbidity and mortality. Methods We present the first four reported US acquired cases of Coxiella burnetii vertebral osteomyelitis caused by contiguous spread from an infected abdominal aortic graft or aneurysm. Results Presenting symptoms included progressive back pain, malaise, and weight loss with recent or remote animal exposure. Typical imaging findings demonstrated a peri-aortic collection with extension to the paraspinal muscles and vertebrae. Antibiotic regimens included doxycycline with either hydroxychloroquine or a quinolone for at least 2 years or as chronic suppression. Conclusions C. burnetii vertebral osteomyelitis is rare and can occur by contiguous spread from an abdominal aneurysm or vascular graft infection. It should be suspected in patients where pre-antibiotic cultures are negative with animal/farming exposure.

Abstract Background While several studies have identified risk factors for PJI using insurance claims data, these data sets have been limited to a single regional insurance dataset or to the Medicare population. We sought to investigate risk factors for early PJI among patients undergoing total hip or knee arthroplasty (THKA). Methods All patients who underwent primary THKA between January 1, 2004 and July 31, 2014 with 12 months of continuous preceding medical and pharmacy insurance coverage were included in the study. The primary outcome of PJI required both a compatible procedure code and a diagnostic code during an inpatient stay from the time of THKA through 90 days after discharge. Comorbidities were based on ICD-9 codes in the preceding 12 months and patients with a prior diagnosis of PJI during that time period were excluded. Univariate and multivariate analysis was performed using logistic regression. Results A total of 147,053 patients underwent THKA during the study period, including 97,448 patients with TKA and 49,605 with THA. PJI occurred in 754 (0.5%) patients. Female gender was independently associated with lower odds of PJI (Figure). A number of biologically plausible factors were associated with increased risk, including chronic skin ulcer, obesity, substance use disorders, joint sarcoma, and malnutrition. The adjusted odds of PJI increased in a stepwise fashion with each increase in the Charlson comorbidity index (CCI), with those with a score of 4 or more having a nearly 2-fold adjusted odds of PJI compared with a score of 0 (OR 1.91; 95% CI 1.29 −2.82). Previously observed risk factors diabetes mellitus, rheumatoid arthritis, and chronic renal failure were associated with increased odds of PJI on univariate analysis, but not after adjustment. Conclusion These data identify several potentially modifiable risk factors for preoperative optimization, including obesity, malnutrition, chronic skin ulcers, and substance-use disorders. The level of comorbidity as assessed by the CCI provides a rough estimate of the increasing risk of PJI. The pathobiology of additional risk factors observed here deserves further study. Disclosures All authors: No reported disclosures.

ABSTRACT Intravenous radiographic contrast medium and amphotericin B are commonly required in the care of patients with fungal infections. Both interventions have proposed nephrotoxicity through similar mechanisms. We systematically examined patients who received coadministration of liposomal amphotericin B (AmBisome; GE Healthcare) and intravenous contrast medium within a 24-h period and compared the results for those patients with the results for patients who underwent non-contrast medium studies. We found 114 cases and 85 controls during our study period. Overall, no increased risk of renal injury was seen with coadministration of these 2 agents. Adjustment for age, baseline kidney function, and other clinical factors through propensity score adjustment did not change this result. Our observations suggest that, when clinically indicated, coadministration of contrast medium and liposomal amphotericin B does not present excess risk compared with that from the administration of liposomal amphotericin B alone.