Objective—To determine whether lactoferrin (LF) or
milk influenced adherence of Streptococcus uberisto
bovine mammary epithelial cells.
Sample Population—Three strains of S uberis from
cows with mastitis, pooled milk samples from 3 clinically
healthy Jersey cows early in the lactation period, and
bovine mammary epithelial cells from a clonal cell line.
Procedures—Adherence of S uberis to bovine mammary
epithelial cells in the presence of various concentrations
of LF or milk and after pretreatment of
bacteria with LF or milk was tested. Bacteria were
cultured with mammary epithelial cell monolayers for
1 hour. The culture supernatant was removed, and
the epithelial cells were lysed. Adherence index was
calculated as number of colony-forming units (CFU) in
the cell lysate divided by number of CFU in the supernatant
Results—All 3 strains of S uberis were found to bind
to purified LF and LF in milk. Addition of LF to the culture
medium enhanced adherence of all 3 strains to
mammary epithelial cells, whereas addition of milk
enhanced adherence of 2 strains and decreased
adherence of the third. Pretreatment of bacteria with
LF or milk increased adherence of 1 of the strains but
decreased adherence of the other 2. Increased
adherence was antagonized by rabbit antibovine LF
Conclusions—Results suggest that LF may function
as a bridging molecule between S uberis and bovine
mammary epithelial cells, facilitating adherence of the
bacteria to the cells. (Am J Vet Res 2000;61:275–279)
Objective—To determine prevalence of within-household sharing of fecal Escherichia coli between dogs and their owners on the basis of pulsed-field gel electrophoresis (PFGE), compare antimicrobial susceptibility between isolates from dogs and their owners, and evaluate epidemiologic features of cross-species sharing by use of a questionnaire.
Sample Population—61 healthy dog-owner pairs and 30 healthy control humans.
Procedures—3 fecal E coli colonies were isolated from each participant; PFGE profiles were used to establish relatedness among bacterial isolates. Susceptibility to 17 antimicrobials was determined via disk diffusion. A questionnaire was used to evaluate signalment, previous antimicrobial therapy, hygiene, and relationship with dog.
Results—A wide array of PFGE profiles was observed in E coli isolates from all participants. Within-household sharing occurred with 9.8% prevalence, and across-household sharing occurred with 0.3% prevalence. No behaviors were associated with increased clonal sharing between dog and owner. No differences were found in susceptibility results between dog-owner pairs. Control isolates were more likely than canine isolates to be resistant to ampicillin and trimethoprim-sulfamethoxazole. Owners and control humans carried more multdrug-resistant E coli than did dogs.
Conclusions and Clinical Relevance—Within-household sharing of E coli was detected more commonly than across-household sharing, but both direct contact and environmental reservoirs may be routes of cross-species sharing of bacteria and genes for resistance. Cross-species bacterial sharing is a potential public health concern, and good hygiene is recommended.
Objective—To determine the prevalence of 4 urovirulence genes in fecal Escherichia coli isolates from healthy dogs and their owners and to determine whether detection of E coli strains with these genes was associated with a history of urinary tract infection (UTI).
Sample Population—61 healthy dog-owner pairs and 30 healthy non–dog owners.
Procedures—A fecal specimen was obtained from each participant, and 3 colonies of E coli were isolated from each specimen. A multiplex PCR assay was used to detect 4 genes encoding virulence factors: cytotoxic necrotizing factor (cnf), hemolysin (hlyD), s-fimbrial and F1C fimbriae adhesin (sfa/foc), and pilus associated with pyelonephritis G allele III (papGIII). Human participants completed a questionnaire to provide general information and any history of UTI for themselves and, when applicable, their dog.
Results—26% (16/61) of dogs, 18% (11/61) of owners, and 20% (6/30) of non–dog owners had positive test results for ≥ 1 E coli virulence gene. One or more genes were identified in fecal E coli isolates of both dog and owner in 2% (1/61) of households. There was no difference in the detection of any virulence factor between dog-owner pairs. Female owner history of UTI was associated with detection of each virulence factor in E coli strains isolated from their dogs' feces.
Conclusions and Clinical Relevance—Dogs and humans harbored fecal E coli strains possessing the genes cnf, hlyD, sfa/foc, and papGIII that encode urovirulence factors. It was rare for both dog and owner to have fecal E coli strains with these virulence genes.