The potential impact of food animals in the production environment on the bacterial population as a result of antimicrobial drug use for growth enhancement continues to be a cause for concern. Enterococci from 82 farms within a poultry production region on the eastern seaboard were isolated to establish a baseline of susceptibility profiles for a number of antimicrobials used in production as well as clinical environments. Of the 541 isolates recovered, Enterococcus faecalis (53%) and E. faecium (31%) were the predominant species, while multiresistant antimicrobial phenotypes were observed among all species. The prevalence of resistance among isolates of E. faecalis was comparatively higher among lincosamide, macrolide, and tetracycline antimicrobials, while isolates of E. faecium were observed to be more frequently resistant to fluoroquinolones and penicillins. Notably, 63% of the E. faecium isolates were resistant to the streptogramin quinupristin-dalfopristin, while high-level gentamicin resistance was observed only among the E. faecalis population, of which 7% of the isolates were resistant. The primary observations are that enterococci can be frequently isolated from the poultry production environment and can be multiresistant to antimicrobials used in human medicine. The high frequency with which resistant enterococci are isolated from this environment suggests that these organisms might be useful as sentinels to monitor the development of resistance resulting from the usage of antimicrobial agents in animal production.

The biofilms and rugose colony morphology of Salmonella enterica serovar Typhimurium strains are usually associated with at least two different exopolymeric substances (EPS), curli and cellulose. In this study, another EPS, a capsular polysaccharide (CP) synthesized constitutively in S. enterica serovar Typhimurium strain DT104 at 25 and 37°C, has been recognized as a biofilm matrix component as well. Fluorophore-assisted carbohydrate electrophoresis (FACE) analysis indicated that the CP is comprised principally of glucose and mannose, with galactose as a minor constituent. The composition differs from that of known colanic acidcontaining CP that is isolated from cells of Escherichia coli and other enteric bacteria grown at 37°C. The reactivity of carbohydrate-specific lectins conjugated to fluorescein isothiocyanate or gold particles with cellular carbohydrates demonstrated the cell surface localization of CP. Further, lectin binding also correlated with the FACE analysis of CP. Immunoelectron microscopy, using specific antibodies against CP, confirmed that CP surrounds the cells. Confocal microscopy of antibody-labeled cells showed greater biofilm formation at 25°C than at 37°C. Since the CP was shown to be produced at both 37°C and 25°C, it does not appear to be significantly involved in attachment during the early formation of the biofilm matrix. Although the attachment of S. enterica serovar Typhimurium DT104 does not appear to be mediated by its CP, the capsule does contribute to the biofilm matrix and may have a role in other features of this organism, such as virulence, as has been shown previously for the capsules of other gram-negative and gram-positive bacteria.

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Broilers under commercial conditions might experience relatively high temperatures during summer and leg disorders year round that may be partially alleviated by providing them with access to cooled perches. It is unknown, however, how perch temperature and factors such as height and position of the perch affect perch use. Furthermore, little is known regarding gender effects. Eight thousand 1-d-old, mixed-sex broilers were exposed to three perch treatments to determine preferences for water-cooled perches over ambient temperature perches and preferences for height, location, and temperature section of the perch. The experimental treatments were as follows: 1) three cool perches 15 cm above the floor (Cool 15), 2) three ambient perches 7.5 cm off the floor (Ambient 7.5), 3) three ambient perches 15 cm high (Ambient 15), and 4) control chambers with no perches. Total number of birds perching, their positions, and temperature section within the perch were recorded. The results indicate a strong preference for high perches as birds grow (P < 0.0001). The cooler sections of the perch were utilized more than warmer sections within the cool treatments (P < 0.05). Females showed a stronger tendency to perch than males, particularly within the cool treatment (P < 0.0001). The higher perch use could be one of the reasons for the higher eviscerated body weight found in females with access to cool perches (P < 0.05). Differences in mean body weight were not significant (P = 0.07). Potential beneficial effects of perch access in final body weights needs to be further investigated.

Because Salmonella spp. can be spread from the production environment to the consumer, strategies are required to control Salmonella. One such intervention involves control of the distribution of the organism in poultry litter. In this regard, we have attempted to determine whether Salmonella spp. are uniformly distributed throughout the litter of commercial poultry houses, or if they are unevenly localized to "hot spots" associated with high surface litter water activity (Aw) and high total moisture levels. Of the 86 houses sampled, 48 (55.8%) were positive for Salmonella spp. using a combination of the drag swab and targeted litter culturing methods. Data are presented that show that elevated Aw and percentage moisture content values representative of targeted litter samples or whole-house moisture status are not statistically predictive of Salmonella contamination, using either drag swab or targeted litter culture results as indicators of contamination. This study suggests that favorable environmental conditions for the growth of Salmonella are unequally dispersed in poultry houses. Because there is not equivalent distribution of salmonellae in the surface litter, the drag swab technique is apparently necessary to adequately survey for Salmonella spp. contamination. The findings further suggest that the development of a methodology to detect areas within houses that possess risk factors favorable for Salmonella growth must also include elevated Aw and percentage moisture content levels. This capability may enable a grower to detect and intervene in these targeted areas with neutralizing procedures, agents, or other substances to provide significant reduction of Salmonella or other poultry-associated food-borne pathogens.