Recent evidence supports a causal relationship between Bartonella (Rochalimaea) henselae, cat-scratch disease (CSD), and bacillary angiomatosis. Cats appear to be the primary reservoir. Blood from 19 cats owned by 14 patients diagnosed with CSD was cultured. Blood samples from cats owned by veterinary students (n ‫؍‬ 25) having no association with CSD or bacillary angiomatosis were cultured as controls. Eighty-nine percent (17 of 19) of cats associated with CSD patients and 28% (7 of 25) of controls were bacteremic with Bartonella species (chi-square ‫؍‬ 16.47; P < 0.001). Twenty-three isolates were characterized as B. henselae, while one isolate from the cat of a CSD patient appeared to be a new Bartonella species. Thirteen cats remained culture positive during the ensuing 12-month period. Our results support the conclusion that B. henselae is the predominant species involved in CSD and is transmitted by cats. The incidence of Bartonella bacteremia in control cats suggests that B. henselae bacteremia is prevalent among the domestic cat population in the United States. Cat-scratch disease (CSD), cat-scratch fever, or benign nonbacterial lymphadenitis was recognized by Robert Debré in 1931, but it was first reported in 1950 (5). A presumptive diagnosis of CSD is made when a patient has an inoculation wound at the site of a cat bite or scratch, regional lymphadenopathy, a positive CSD skin test, and negative test results for brucellosis, infectious mononucleosis, mycobacteria, syphilis, and tularemia. The search for the etiologic agent was intensified after Wear et al. (40) described the presence of small, silver-staining bacilli in lymph nodes from 28 CSD patients. In 1990, Relman et al. (29) used PCR to amplify Bartonella DNA from bacillary angiomatosis (BA) lesions of four immunocompromised individuals, including one woman who had recently experienced a severe cat scratch. The causative agent eluded isolation attempts until concurrent reports by Welch et al. (42) and Regnery et al. (26) described the recovery of small gram-negative rods from both immunocompetent and immunocompromised patients by the lysis-centrifugation blood culture technique. The organisms were determined to be closely related to Bartonella quintana and were subsequently named Bartonella henselae. The molecular characterization and cultivation of B. henselae facilitated development of an indirect fluorescentantibody (IFA) test which was used by Regnery et al. (27, 28) to identify a seropositive B. henselae bacteremic cat. Soon thereafter, Koehler et al. (16) reported the isolation of Bartonella species from the BA lesions of four immunocompromised patients. B. quintana was found in three patients denying cat or arthropod contact, while B. henselae was cultured from the blood of the fourth patient who had obtained several scratches from his flea-infested cat and kitten. In 1993, Dolan et al. (7) described two immunocompetent patients with B.

In the course of our molecular studies of virulence factors associated with invasive avian Escherichia coli infections, it was first necessary to distinguish between common E. coli and those that cause septicemia in poultry. We found a direct correlation between the ability of clinical isolates of E. coli to bind Congo red dye (CR) and their ability to cause septicemic infection in chickens. This finding was supported by bacteriological studies of 30 broiler flocks (26 sick and 4 healthy) and by virulence studies in chickens and mice. All 144 isolates of E. coli from internal tissues of diseased birds were determined to be CR-positive (red colonies). Congo-red-positive E. coli colonies were isolated from air sacs, pericardium, liver, lung, joint fluid, and heart blood of chickens with lesions of colisepticemia. In contrast, of 170 E. coli isolates from the poultry house environment and from the trachea and cloaca of healthy birds, more than half were CR-negative (white colonies). No CR-negative (white) E. coli colonies were found in internal organs from birds with typical lesions of colisepticemia. We feel that these preliminary findings suggest that the CR dye binding could be used as a phenotypic marker to distinguish between invasive and noninvasive isolates.

Immunoblots were used to study the immunoglobulin G response to Borrelia burgdorferi in experimentally and naturally exposed dogs. Adsorption studies confirmed that the antibodies were specific for B. burgdorferi. Experimentally exposed dogs were asymptomatic. Naturally exposed dogs included both asymptomatic animals and animals showing signs compatible with Lyme disease. Naturally exposed dogs were from four geographic regions of the country. No differences were detected between immunoblot patterns of naturally exposed symptomatic or asymptomatic dogs from different areas of the country. The immunoblot patterns obtained with sera from experimentally exposed dogs were different from those obtained with sera from naturally exposed dogs and were characterized by reactivity toïfewer and different protein bands. Immunoblot analysis using an OspA-protein-producing Escherichia coli recombinant showed that experimentally exposed dogs produced antibodies to OspA, whereas naturally exposed dogs did not. Modifications of the immune response over time, different routes of antigen presentation, and strain variation are factors postulated to account for thé observed differences.

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ABSTRACT. One hundred and thirty-eight strains of Staphylococcus hyicus and 21 strains of S. chromogenes isolated from animals were analyzed by pulsed-field gel electrophoresis (PFGE) after restriction endonuclease SmaI digestion of chromosomal DNA. Eighty-eight strains of S. hyicus from pigs with or without exudative epidermitis (EE) generated 16 to 26 fragments in the size range of <1 to 485 kb, and yielded 39 different patterns. With regard to the strains from pigs with EE, PFGE patterns differed according to the country of origin. Outbreaks of EE occurring on four separate pig farms in Japan involved S. hyicus with different PFGE patterns. The PFGE patterns shown by S. hyicus strains from 4 kinds of animals were compared. Strains from pigs differed from those isolated from chickens (n=45; 18 to 24 fragments of <1 to 425 kb), cows (n=3; 17 to 19 fragments of <1 to 475 kb), and goats (n=2; 16 or 17 fragments of <1 to 1,125 kb). Also, each of the chicken, cow and goat strains had a host-specific fragment. The results suggest that PFGE analysis might be a useful marker for distinguishing ecovars within S. hyicus. In contrast, strains of S. chromogenes from pigs and cows generated 17 to 24 fragments ranging from <1 to 545 kb. The PFGE patterns of S. chromogenes strains were more highly conserved than those of S. hyicus. S. chromogenes strains could be distinguished from S. hyicus strains by fragments within the range of 305 to 545 kb. The results indicate that PFGE analysis could be used to distinguish between S. hyicus and S. chromogenes. We conclude that PFGE analysis is a useful tool not only for species or strain identification but also for epidemiologic or ecologic studies of S. hyicus and S. chromogenes. -KEY WORDS: genomic DNA fingerprinting, pulsed-field gel electrophoresis, Staphylococcus chromogenes, Staphylococcus hyicus.