Antibiotic resistance among enterococci and fecal streptococci was examined by testing 149 isolates from pork, water, and clinical material, as well as 50 strains of 13 known species, for resistance to 27 different antimicrobial agents. Tests were performed by using the MicroScan Pos MIC type 6 panels. Pork isolates exhibited less resistance than either water or clinical isolates to most antibiotics, although a larger proportion of pork isolates than others was resistant to tetracycline. Comparisons of antimicrobial-resistance patterns between enterococcal species revealed that Enterococcus faecium was most resistant to β-lactam antimicrobials, especially ampicillin, whereas Enterococcus faecalis seemed to be the most resistant to the synergistic effects of antimicrobial combinations. Vancomycin resistance was observed in one Enterococcus hirae isolate from water. Enterococcal isolates from any of the sources tested did not show multiple resistance to antibiotics (such as gentamicin, ampicillin, streptomycin, and vancomycin) used to treat serious infections caused by gram-positive cocci.

Over the past 6 years, a revised classification of the streptococci and enterococci, based primarily on molecular techniques such as 16S rRNA sequencing and DNA-DNA hybridization, emerged. However, little attention was placed on routine physiological tests that could be used in food and clinical laboratories to differentiate between species of a new genus, Enterococcus, and fecal Streptococcus spp. The purpose of this study was to devise a convenient and reliable system to identify enterococci and fecal streptococci by using conventional procedures. Fifty-nine strains of 13 Enterococcus spp., including the type strains and many strains used by previous investigators, were characterized by using conventional tube tests, the API Rapid Strep system, and MicroScan Pos ID panels. Results were compared with each other and with previously published results. A comparison of conventional tube tests versus published tube test results yielded 17 discrepancies. Although not all tests were done with each of the three systems, 28 discrepancies between results obtained with the API system and those obtained with conventional tube tests were found. There were 24 discrepancies between results obtained with the MicroScan Pos ID panel and those obtained with conventional tube tests. There were 12 discrepancies between the results with the API Rapid Strep system and those with the MicroScan Pos ID panels. We devised flow charts of key tests that might be used to identify cultures without resorting to nucleic acid analysis and other laborand equipment-intensive analyses.

The purpose of this study was to determine the numbers and species of enterococci encountered on pork carcasses during different stages in the slaughter process as well as on pork products. Three hog slaughtering plants were surveyed, each 3 times at four processing points. Each hog was swabbed at two sites on the carcass. Specimens were plated on two different enterococcal media, KF streptococcal agar and fluorescent gentamycin-thallous-carbonate agar. Retail and spoiled pork sausage products also were examined. Isolates were speciated by using the API Rapid Strep and Baxter MicroScan Pos ID panels. Contamination levels varied between plants as the carcasses progressed down the processing line; the highest counts were obtained directly before packaging in plants A and C. The highest count for plant B occurred at the first stage of sampling. More Enterococcus faecalis than Enterococcus faecium were isolated from the pork carcasses. Pork sausage results also are presented. Enterococci are useful as an indicator of pork sanitation and to detect critical control points during processing. In some instances, high levels of enterococci are associated with spoilage of pork sausage.

Two selective and differential media were compared for their abilities to enumerate enterococci and fecal streptococci in pork, beef, and poultry products. Counts obtained on KF streptococcal (KF) agar were compared with counts obtained on fluorescent gentamicin-thallous-carbonate (fGTC) agar. Reactions of 13 known enterococcal species were also observed. All 13 species of enterococci as well as Streptococcus bovis and Streptococcus equinus grew equally well on fGTC agar. KF streptococcal medium allowed growth of most species of enterococci but not S. bovis and S. equinus. Quantitative comparisons between the two media inoculated with pure cultures of known species of enterococci revealed equivalent plate counts following incubation. However, when meat samples were plated, counts on fGTC agar were consistently and significantly higher than counts on KF agar for all sample sources.

History of the Enterococci 4 Origin of the species of the genus Enterococcus Importance of the Enterococci 12 Habitat of the enterococci 12 Enterococci as fecal indicators in food and water 14 Enterococci in Meats Enterococci as a cause of food spoilage 18 Hazard analysis critical control points 19 Meat sampling techniques 21 Enterococci in Food Poisoning Clinical Importance of the Enterococci 24 Isolation and Identification Methods for the Enterococci Selective media Rapid methods for identification Molecular approaches to identification PAPER 1. ROUTINE PROCEDURES FOR ISOLATION AND