Canine bartonellosis: serological and molecular prevalence in Brazil and evidence of co-infection with Bartonella henselae and Bartonella vinsonii subsp. berkhoffii

The purpose of this study was to determine the serological and molecular prevalence of Bartonella spp. infection in a sick dog population from Brazil. At the S?o Paulo State University Veterinary Teaching Hospital in Botucatu, 198 consecutive dogs with clinicopathological abnormalities consistent with tick-borne infections were sampled. Antibodies to Bartonella henselae and Bartonella vinsonii subsp. berkhoffii were detected in 2.0% (4/197) and 1.5% (3/197) of the dogs, respectively. Using 16S-23S rRNA intergenic transcribed spacer (ITS) primers, Bartonella DNA was amplified from only 1/198 blood samples. Bartonella seroreactive and/or PCR positive blood samples (n=8) were inoculated into a liquid pre-enrichment growth medium (BAPGM) and subsequently sub-inoculated onto BAPGM/blood-agar plates. PCR targeting the ITS region, pap31 and rpoB genes amplified B. henselae from the blood and/or isolates of the PCR positive dog (ITS: DQ346666; pap31 gene: DQ351240; rpoB: EF196806). B. henselae and B. vinsonii subsp. berkhoffii (pap31: DQ906160; rpoB: EF196805) co-infection was found in one of the B. vinsonii subsp. berkhoffii seroreactive dogs. We conclude that dogs in this study population were infrequently exposed to or infected with a Bartonella species. The B. henselae and B. vinsonii subsp. berkhoffii strains identified in this study are genetically similar to strains isolated from septicemic cats, dogs, coyotes and human beings from other parts of the world. To our knowledge, these isolates provide the first Brazilian DNA sequences from these Bartonella species and the first evidence of Bartonella co-infection in dogs.     

Postoperative infection with Actinobacillus spp in horses: 10 cases (1995-2000)

OBJECTIVE: To determine features of postoperative wound infection caused by Actinobacillus spp in horses undergoing clean, elective surgery and to evaluate bacterial susceptibility profiles of bacteria isolated. DESIGN: Retrospective study. ANIMALS: 10 horses. PROCEDURE: Data were retrieved from medical records and the microbiology laboratory database. RESULTS: 1,604 horses underwent clean, elective surgical procedures during the study period. Of these, 23 (1.43%) had postoperative wound infections, and Actinobacillus spp was isolated from 10 of these 23 (43%). Surgical procedures in these 10 horses included laryngoplasty with ventriculocordectomy (n = 3), arthroscopy (3), desmotomy of the accessory ligament of the superficial digital flexor tendon (2), removal of laryngoplasty prostheses (1), and hygroma resection (1). Seven horses survived, and 3 were euthanatized. All 10 Actinobacillus isolates were resistant to penicillin, and 6 were resistant to trimethoprim-sulfamethoxazole. All isolates were susceptible to ceftiofur and gentamicin. During the 5-year period of the study, Actinobacillus organisms were isolated from 35 of 513 (6.8%) samples from the general hospital population submitted for bacterial culture and antimicrobial susceptibility testing. CONCLUSIONS AND CLINICAL RELEVANCE: During the study period, Actinobacillus spp was isolated from a higher than expected percentage of horses that developed postoperative wound infections after clean, elective surgery. Susceptibility profiles for these isolates were different from typical susceptibility profiles for Actinobacillus isolates, suggesting that a pattern of resistance may be emerging.     

Timing and causes of piglet mortality in alternative and conventional farrowing systems

The causes and timing of piglet mortality were studied in different farrowing systems. In the first experiment 198 litters were recorded in three systems, two of which allowed the sows to move freely, and the third restricted them in conventional crates. More piglets were weaned from the conventional crates than from the open systems and they grew more quickly. More than half the liveborn mortality occurred during the first four days after parturition. In the open systems, 17 per cent and 14 per cent of the piglets born alive were crushed, compared with only 8 per cent in the crates. In the second experiment, 29 sows and litters were studied in detail in a communal pen system during the first seven days of lactation. Three-quarters of the liveborn mortality was due to crushing. The total number of piglets dying per litter, including stillbirths, was significantly associated with the total litter size and the sow's parity. The percentage liveborn mortality was significantly associated with the parity and body length of the sows and with the within-litter variation in the birth weight of the piglets. Individual birth weight was closely associated with percentage survival. Only 28 per cent of piglets weighing less than 1.1 kg at birth survived to seven days.     

Patterns of antimicrobial susceptibility in Michigan wildlife and bovine isolates of Mycobacterium bovis.

The state of Michigan has recognized the presence of Mycobacterium bovis in its free-ranging white-tailed deer population since 1994. This endemic infection is primarily located in a 12-county area in the northeastern lower peninsula of Michigan. A statewide surveillance and eradication program of the disease has been in effect since 1994. Worldwide, Mycobacterium tuberculosis complex organisms have a known predilection toward development of antimicrobial resistance. The objective of this study was to investigate the antimicrobial susceptibility of M. bovis isolates from white-tailed deer in Michigan and detect any changes in susceptibility over time. M. bovis isolates from 2 fall hunting seasons (1999 and 2004) were used in this study. The fall season of 2004 marked the first documented case of direct transmission of M. bovis from a wild deer to a human in Michigan. Since M. bovis is a zoonotic disease, knowledge of susceptibility can expedite treatment options in humans. M. bovis isolates were obtained from 58 deer, 4 coyotes, 3 cattle, 2 raccoons, and 1 human case from the 2 years combined. Methods of susceptibility testing included 1% proportion agar plates and Bactec radiometric broth testing. M. bovis was found to be uniformly resistant to the antibiotic pyrazinamide; this resistance is common to all M. bovis isolates. No other antimicrobial resistance was found in any of the tested M. bovis isolates, which may be, in part, attributed to the lack of any significant treatment pressure in wildlife.