Methods for the detection of viruses in bovine serum

A unified method to process biosolids samples for the recovery of bacterial, viral, and helminths pathogens

For land application, biosolids are classified as Class A or Class B based on the levels of bacterial, viral, and helminths pathogens in residual biosolids. The current EPA methods for the detection of these groups of pathogens in biosolids include discrete steps. Therefore, a separate sample is processed independently to quantify the number of each group of the pathogens in biosolids. The aim of the study was to develop a unified method for simultaneous processing of a single biosolids sample to recover bacterial, viral, and helminths pathogens. At the first stage for developing a simultaneous method, nine eluents were compared for their efficiency to recover viruses from a 100 gm spiked biosolids sample. In the second stage, the three top performing eluents were thoroughly evaluated for the recovery of bacteria, viruses, and helminthes. For all three groups of pathogens, the glycine-based eluent provided higher recovery than the beef extract-based eluent. Additional experiments were performed to optimize performance of glycine-based eluent under various procedural factors such as, solids to eluent ratio, stir time, and centrifugation conditions. Last, the new method was directly compared with the EPA methods for the recovery of the three groups of pathogens spiked in duplicate samples of biosolids collected from different sources. For viruses, the new method yielded up to 10% higher recoveries than the EPA method. For bacteria and helminths, recoveries were 74% and 83% by the new method compared to 34% and 68% by the EPA method, respectively. The unified sample processing method significantly reduces the time required for processing biosolids samples for different groups of pathogens; it is less impacted by the intrinsic variability of samples, while providing higher yields (P = 0.05) and greater consistency than the current EPA methods.

An adventitious viral contaminant in commercially supplied A549 cells: identification of infectious bovine rhinotracheitis virus and its impact on diagnosis of infection in clinical specimens

The isolation and identification of an adventitious viral agent, infectious bovine rhinotracheitis virus, in one lot of A549 cells from a commercial supplier is described in this report. The presence of infectious bovine rhinotracheitis virus in A549 cells was unexpected and has caused problems in the diagnosis of infections in clinical specimens in three laboratories.

Elimination of bacteriophages from tissue culture serum by affinity chromatography

Use of immunoadsorbents to remove bacteriophages from tissue culture serum was investigated. Immune globulins from rabbit antiserum prepared against phi V-1 phage were immobilized by covalent linkage to activated porous silica glass derivatives of p-aminoarylamine and to Sepharose-4B. Chromatographic columns of each material were used to filter samples of a fetal bovine serum into which had been introduced 8100 plaque-forming units of the phage per ml. Efficiency of removal was determined by plaque assays of phi V-1 phage recovered in the effluent fluids. Activated but uncoupled matrices nonspecifically removed from 49 to 59% of the phages introduced into the experimental serum. A reduction of 35 to 37% in phage content occurred in the serum after filtration through columns coupled to nonantibody protein. With specific immune globulins attached, the Sepharose-4B matrix reduced the concentration of phage in the serum below a detectable quantity. Noapparent alterations occurred in the growth-promoting property of serum filtered through the Sepharose-4B immunoadsorbent as measured by cloning efficiency of BHK-21, WI-38, and FRhL-2 cells. These experiments serve as a model system for use of immunoadsorbents for selective removal of bacteriophages and perhaps other extraneous microbial agents from tissue culture serum.

Inactivation of viruses in serum with binary ethyleneimine

The inactivation os six strains from three different groups of viruses with 0.001 M binary ethyleneimine at 37 C proceeded at the same rate in either bovine serum or cell culture medium. The inactivant did not impair the growth-promoting capacity of bovine serum used in cell culture, nor did it affect the antibody activity of guinea pig hyperimmune serum.

Use of electron microscopy for detection of viral and other microbial contaminants in bovine sera

A total of 25 lots of bovine serum samples were pelleted in Beem capsules for thin sectioning and were examined by electron microscopy. These included 17 lots of fetal bovine serum pools and five lots of calf serum pools obtained from commercial sources, and three lots of adult bovine serum from local dairy farms. Virus-like particles, 50 to 300 nm in diameter, were detected in 17 of 25 (68%) of the sera. Five of 25 serum samples showed the presence of mycoplasma-like agents. Incubation of bovine serum at 35 C for 1 or 2 weeks appeared to destroy some of these agents, but in certain instances it enhanced bacteria and bacteriophage contaminants. The advantages of electron microscopy using the thin-sectioning technique for detection of microbial contamination in bovine sera are illustrated.