Discussion
Brucellosis is a zoonotic disease transmitted to humans through contact with animal hosts. Transmission can occur via breaks in the skin in direct contact, through the ingestion of unpasteurized dairy products or raw meat, or through ingestion of aerosolized bacteria. Transmission via aerosolization has been described during medical procedures.
Brucella is endemic in India, Middle Eastern and Mediterranean countries, Central Asia, and South America. Brucella species are gram-negative coccobacilli that are capable of surviving within phagocytic cells, making antibiotic treatment difficult. Brucellosis is a febrile illness that occurs after a 1- to 3-week incubation period and is often accompanied by headache, arthralgias, and hepatosplenomegaly. Osteoarticular infection is the most common complication, occurring in 10% to 85% of cases and usually involves the sacroiliac joint and the large joints of the lower extremity. Spondylitis, bursitis, tenosynovitis, endocarditis, colitis, meningitis, and osteomyelitis have also been described.7,14-17
As mentioned previously, 18 cases of infected THAs and total knee arthroplasties (TKAs) in 16 patients were identified in the English literature: 9 THAs and 9 TKAs.1-12 With the exception of 1 case reported in Texas, all others were from the Middle East or the Mediterranean region. In these patients, symptom onset occurred from 2 months to 14 years from the time of the index surgery, and symptom duration ranged from 1 month to 2 years prior to presentation. The exposure was not reported in 2 cases, but the remaining patients either ingested unpasteurized dairy products or worked closely with livestock. Laboratory evaluation revealed elevated ESR or CRP in 8 cases. In 7 cases, no laboratory results were reported, although 1 had a draining sinus. In 1 case, the ESR was normal, but a bone scan was positive. Joint aspiration yielded Brucella species in 8 cases, was negative in 3, and not reported in 5 cases (one aspirate yielded Acinetobacter baumanii). Only 3 cases reported a time-to-culture positivity (1 “prolonged” and 2 took 7 days).
Eight cases presented with loose components, while 1 case was not reported, and the remaining were presumed to be well-fixed. In cases that were identified as loose, 5 underwent a 2-stage revision and 2 underwent a 1-stage revision (in one of the 1-stage revisions, the infection was identified only after the revision from intra-operative cultures). Of those with well-fixed components, 7 patients with 9 infected joints (including the case where no preoperative description of the components was reported) were treated with oral antibiotics only (range, 6 weeks to 26 months) and 1 with irrigation and débridement and oral antibiotics. Among those treated only with antibiotics, there were 2 failures (2 joints) leading to revision surgery. The other 5 cases were reportedly doing well between 8 months and 5 years after treatment. There were no reports of transmission to hospital or laboratory personnel in any of these cases nor were there reports of precautions to limit exposure for operating room staff or hospital personnel.
Failure of TKA or THA secondary to periprosthetic infection by Brucella species is rare, and this represents only the second reported case in the United States.4 This case highlights several important principles. Maintaining a high level of suspicion for infection in cases of failed joint arthroplasty is important. In addition, as more international travel occurs and patients are seen from areas where Brucella is endemic, the possibility of this infectious etiology should be considered. Based on reported cases, patients will usually have elevated ESR or CRP; all (except 2 cases in which no exposure was reported) had known exposure to unpasteurized dairy products or livestock. Joint aspiration yielded Brucella species in 8 cases, was negative in 3, and not reported in 5 cases (1 aspirate yielded Acinetobacter baumanii). In this case, ESR and CRP were elevated, and infection was suspected but joint aspiration was negative. The initial aspiration was cultured for 5 days and previous data, as well as that presented here, suggest that prolonged culture may provide diagnostic value.18 The patient had resided in an endemic area and had exposure to unpasteurized dairy products, but Brucella infection was not considered and, therefore, no precautions were taken.
Of the reported cases, only 1 met major criteria for periprosthetic joint infection (draining sinus) while 10 of the remaining 15 cases were positive for minor criteria of periprosthetic joint infection (elevated ESR or CRP, or positive culture from joint aspiration).19 Unfortunately, the available case reports did not detail the extent to which preoperative periprosthetic joint infection could be established based on minor criteria for periprosthetic joint infection (elevated joint synovial white blood cell count or neutrophil percentage, intra-articular purulence, or elevated neutrophil count on periprosthetic tissue histologic analysis).19