Abstract. The polymerase chain reaction was employed to correlate Salmonella serovars isolated from fecal material of greyhounds suffering from gastroenteritis with those isolated from the diet fed to the greyhounds prior to onset of diarrhea. Kennels around the Abilene, Kansas, area were contacted and supplied with materials needed to collect a portion of the diet each day. With t e onset of diarrhea, the kennels were instructed to ship the fecal material and diet from the previous 10 days to the laboratory for testing. Forty-one fecal samples and corresponding diets were screened for Salmonella, Clostridium perfringens, Campylobacterjejuni, Staphylococcus aureus, Staphylococcus intermedius, and pathogenic (piliated) Escherichia coli by direct culture using standard procedures. The fecal material was also screened for coronavirus and parvovirus using electron microscopy. Thirty-five "normal" fecal samples were screened for all of the above mentioned microorganisms as a control. In addition, the fecal material was screened for E. coli verotoxins I and II and clostridial enterotoxins. A total of 61 Salmonella isolates were recovered from the 41 samples of feces and diet submitted for testing; 31 were recovered from the feces and 30 from the diet. Four Salmonella isolates were recovered from the normal fecal samples. Results obtained by PCR, plasmid profiles, antigenic analysis, and antibiogram profiles indicated that 16 of the 31 isolates recovered from the fecal material were the same strain as that recovered from the diet.

Rapid and accurate determination of the Actinobacilus pleuropneumoniae serotype involved in a disease outbreak is important both in limiting the severity of an outbreak and for tracing the source of the infecting organism. This study describes the use of arbitrarily primed polymerase chain reaction (AP-PCR) as a rapid, precise, and genetically based procedure to identify A. pleuropneumoniae. AP-PCR amplification of bacterial genomic DNA results in specific DNA profiles, which can be used to differentiate currently recognized serotypes. This technique is especially useful for identifying previously nontypeable and serologically cross-reactive A. pleuropneumoniae field isolates. Consecutive passages of isolates on different media, freezing, and subsequent infection of pigs did not alter the AP-PCR genomic profile. We propose the use of M13 and T3-T7 oligodeoxynucleotide primers for diagnostic and epidemiological identification ofA. pleuropneumoniae by AP-PCR techniques.

An assay to identify tissue culture cells infected with bovine respiratory syncytial virus (BRSV) that utilizes reverse transcription (RT), the polymerase chain reaction (PCR), and a synthetic oligonucleotide hybridization probe has been developed. The RT-PCR assay uses a BRSV-specific negative-sense oligonucleotide primer to synthesize cDNA from a BRSV fusion protein mRNA template and another BRSV-specific oligonucleotide primer (positive sense) upstream from the negative-sense primer for PCR amplification. In the presence of mRNA templates of BRSV isolates originating from locations throughout the United States, the BRSV RT-PCR assay resulted in amplified products (381 bp) that were specific to BRSV, as demonstrated in hybridizations with a positive-sense oligonucleotide probe complementary to internal sequences and in sequence comparisons with the F protein of BRSV 391-2. In analysis of the BRSV RT-PCR assay with prototype strains of human RSV subgroups A and B, amplification of a similar 381-bp RT-PCR product was not evident, and no RT-PCR product hybridized with the internal probe. We conclude that the specific ability to amplify DNA sequences of BRSV F protein mRNA by RT-PCR and then to demonstrate the presence of the amplified product with a BRSV-specific oligonucleotide probe will greatly add to the speed, sensitivity, and specificity of BRSV diagnostics. Bovine respiratory syncytial virus (BRSV), a pneumovirus in the family Paramyxoviridae, is an important cause of acute respiratory disease in postweaning calves and feedlot cattle in the United States (1-3, 6). In Europe, BRSV infection is considered one of the most significant causes of bovine respiratory disease (11, 23). Although most infections are inapparent (2, 6, 12), the high prevalence of seropositive * Corresponding author. t Contribution no. 93-146-J from the Kansas Agricultural Experiment Station.

Abstract. Actinobacillus pleuropneumoniae biotype 2 was isolated in pure culture or as the predominant isolate from the lungs of 9 growing and finishing pigs with pleuropneumonia. Gross and microscopic lesions resembled those caused by A. pleuropneumoniae biotype 1 serotypes (nos.

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