ASSESSMENT OF THE BACTERIAL-FLORA OF THE PROXIMAL PART OF THE SMALL-INTESTINE IN HEALTHY CATS, AND THE EFFECT OF SAMPLE COLLECTION METHOD

Objective-To investigate the bacterial flora of the proximal part of t he small intestine of healthy cats and determine the effect of sample collection method on results of bacteriologic culture. Animals-25 heal thy barrier-maintained specific pathogen-free-derived cats. Procedure- Aspirated, undiluted samples of proximal small intestinal juice were o btained via oral endoscopy (UEA), and a second sample was collected af ter instillation of 1 mi of sterile saline solution (diluted, DEA). Un diluted juice also was obtained by direct needle aspiration (NA) from the intestinal lumen. Samples for quantitative and semiqualitative bac teriologic examination were grown aerobically and anaerobically. Resul ts-Mean (range) log(10) colony-forming units of total bacteria/ml were 6.2 (2.0 to 8.3) for NA, 6.0 (2.0 to 7.9) for UEA, and 4.9 (2.0 to 7. 5) for DEA samples. One cat had no growth (less than or equal to 2.0 c olony-forming units/ml) for samples obtained using all 3 methods, and another cat had no growth for the DEA sample only. Mean total aerobic, anaerobic, and bacterial counts were not significantly different betw een NA and UEA methods, but these techniques yielded significantly hig her mean counts than did DEA samples (P less than or equal to 0.002, A NOVA). As a percentage of the total bacteria isolated, anaerobes const ituted a median 35, 32, and 50% of the NA, UEA, and DEA samples, respe ctively. Good correlation was found between the NA and UEA samples for total bacteria, aerobes, and anaerobes (r greater than or equal to 0. 830). Conclusions-Compared with human beings, healthy cats carry high numbers of bacteria in the proximal part of the small intestine. By co mparison with NA samples, UEA samples accurately reflected bacterial p opulations in the small intestine, whereas DEA samples significantly u nderestimated these populations.