Prevention of Laboratory-Acquired Brucellosis: Significant Side Effects of Prophylaxis

Reference 1. Lawn S, Wood R. How can earlier entry of patients into antiretroviral programs in low-income countries be promoted? Clin Infect Dis 2006; 42:431–2 (in this issue). Sir—We describe our experience in responding to a laboratory exposure to Bru-cella melitensis—in particular, the high incidence of adverse events associated with antibiotic prophylaxis. This information may be useful to other laboratories with similar exposures. A 45-year-old man returned to Austra-lia from Iraq. He presented to the hospital with a cerebrovascular accident and was noted to be febrile and to have a systo-lic murmur. An echocardiogram demonstrated a vegetation on the aortic valve, and blood cultures grew B. melitensis after 2 days. His condition was treated with a combination of rifampicin, doxycycline, and gentamicin, and he had an uneventful recovery. In the laboratory, the blood cultures were continuously monitored by the BacT/Alert 3D instrument (bioMérieux). When the bottles signaled positive results, they were moved to a class II biological safety cabinet (BSC II), where the bottles were accessed and an aliquot was transferred to a slide and was also placed onto solid agar media. The inoculated media were removed from the cabinet, and plate streaking was performed on an open bench. Initial plate reading and manipulation of the cultures were performed on the open bench, but, within 24 h of the appearance of growth, a presumptive identification of Brucella species was made, after which all further manipulation was performed in the BSC II. The organism was confirmed to be B. melitensis by a reference laboratory. It was thought that staff may have been exposed to the organism during these procedures. Staff were interviewed about their exposure and were assigned to high-, medium-, and low-risk groups. Seven staff members were assigned to the high-risk group. These staff manipulated or handled open-plate cultures or potentially inhaled material from the liquid or plate cultures outside the BSC II (i.e., they sniffed the plate, streaked the plate with flamed loops, inspected open-plate cultures, or performed subcultures or biochemical tests). The medium-risk group members were in close proximity while these procedures were being performed (12 staff), and the low-risk group members were working in other areas of the bacteriology laboratory (25 staff). We decided our response would be similar to that reported by Robichaud et al. [1]. After counseling, the high-risk group was offered antimicrobial prophy-laxis with rifampicin (450 or 600 mg once daily, depending on body …