Infected air-borne particles liberated on opening screw-capped bottles

An outbreak of Brucella melitensis infection by airborne transmission among laboratory workers

An outbreak of acute brucellosis infection was detected among the employees of a biologicals manufacturing laboratory located in Girona, Spain. The first cases appeared six weeks after a vaccine with attenuated Brucella melitensis, Rev-1 had been produced for one week. A clinical and epidemiologic investigation conducted among the 164 employees found 22 patients with clinical symptoms and positive serology, and six patients detected by serology only (attack rate: 17.1 per cent). Blood cultures were obtained from two patients and Brucella melitensis was isolated. Employees working in areas with open windows above the laboratory air extracting system had an attack rate of 39.5 per cent, substantially higher than those working in other locations. When vaccine was manufactured again, an electric oven reaching 300 degrees C had been installed in the air extracting system just before its exit to the exterior. Appropriate culture medium plates were exposed to the laboratory air before and after passing through the oven. Brucellae were isolated from the plates exposed to the air before passing through the oven but not after doing so.

Aerosol hazards from some clinical laboratory apparatus

Infectious diseases, such as infectious hepatitis, may be transmitted from patients to staff in clinical laboratories and dialysis units during the performance of necessary procedures. This prompted us to examine the propensity of several items of commonly used apparatus to produce aerosols of infected blood. These were a microhaematocrit centrifuge, an AutoAnalyzer stirrer, and a microtonometer. We also compared some blood sample tubes with two types of lid. The results showed that all of these are potential sources of infection for laboratory staff.

Particle size distribution of Serratia marcescens aerosols created during common laboratory procedures and simulated laboratory accidents

Andersen air samplers were used to determine the particle size distribution of Serratia marcescens aerosols created during several common laboratory procedures and simulated laboratory accidents. Over 1,600 viable particles per cubic foot of air sampled were aerosolized during blending operations. More than 98% of these particles were less than 5 mu in size. In contrast, 80% of the viable particles aerosolized by handling lyophilized cultures were larger than 5 mu. Harvesting infected eggs, sonic treatment, centrifugation, mixing cultures, and dropping infectious material produced aerosols composed primarily of particles in the 1.0- to 7.5-mu size range.