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The API 20S system (Analytab Products, Plainview, N.Y.) and the AutoMicrobic Gram-Positive Identification system (GPI; Vitek Systems, Hazelwood, Mo.) were evaluated for their capacity to identify the non-beta-hemolytic streptococci and aerococci to the species level. The 20S system identified 86% (six of seven strains) of nonhemolytic group B streptococci, whereas 100% of the same group B streptococcal strains were correctly identified by the GPI system. With both systems 99% (134 of 135 strains) of four species of group D enterococcus strains and 92% (24 of 26 strains) of the Aerococcus spp. strains were identified. The 20S system identified 84% (41 of 49 strains) of three species of group D non-enterococcus strains. The GPI system identified 96% of the same group D non-enterococcus strains. The 20S system identified 84% (190 of 226 strains) of 10 species of viridans streptococci; however, supplemental conventional tests were required to identify 49% (110 of the 226 strains) of the viridans strains to the species level. The GPI system identified 79% of the same viridans streptococci without the need for supplemental tests. Both systems identified 84% (161 of 192 strains) of the seven most commonly occurring viridans Streptococcus spp. The 20S system identified 82% (75 of 92 strains) and the GPI system identified 84% (54 of 64 strains) of Streptococcus pneumoniae.

Nineteen isolates of Alloiococcus otitidis from ear fluid samples collected by tympanostomy from patients at four geographic locations were identified by phenotypic characterization and genetic relatedness. Initial growth of A. otitidis isolates occurred after 3 days at 37؇C on brain heart infusion (BHI) agar with 5% rabbit blood. Heavy growth occurred in BHI broth supplemented with 0.07% lecithin and 0.5% Tween 80 after 4 days of incubation. The isolates were gram-positive cocci that divided on an irregular plane and produced metabolic lactic acid, pyrrolidonyl arylamidase, and leucine aminopeptidase. These cocci grew sparsely in 6.5% NaCl-BHI broth, were asaccharolytic on both fermentative and oxidative bases, and were cytochrome negative by the iron-porphyrin test. The cellular fatty acid profile of A. otitidis was distinguished from those of related genera and characterized by major amounts (>14%) of 16:0, 18:2, 18:1 9c, and 18:0 and smaller amounts of 14:0, 16:1 7c, 17:0, and 18:1 7c. Fifteen isolates demonstrated >69% relatedness by DNA-DNA hybridization. Four isolates plus the original 15 were confirmed as A. otitidis by dot blot hybridization with a digoxigenin-labeled nucleotide probe specific for this species. The intergenic space between the genes coding for the 16S and 23S rRNAs of alloiococci was amplified by PCR, analyzed by restriction fragment length polymorphism, and determined to consist of three different genetic types. Although ␤-lactamase negative, A. otitidis demonstrated intermediate levels of resistance to beta-lactams, including expanded-spectrum cephalosporins, and were resistant to trimethoprim-sulfamethoxazole and erythromycin. Alloiococcus otitidis was first isolated from the ear fluid samples of children in a clinical study of chronic otitis media in Buffalo, N.Y. (10). Fifteen A. otitidis isolates were collected from 320 tympanocentesis fluid samples collected during effusive episodes of 200 patients with otitis media. In a study in Atlanta, Ga., of patients undergoing tympanostomy and tube placement, A. otitidis was isolated from 5 of 108 ear fluid samples collected from young children with chronic otitis media during 1991 and 1992 (20). The children had otalgia and middle ear effusion, with reddened, thickened, and retractive tympanic membranes. Two of the 5 Atlanta isolates and 10 of the 15 New York isolates were the only organisms found in the chronically effusive ear fluid samples, indicating a potential association between this bacterium and chronic effusive otitis. In 1992, British researchers designated this organism a new genus and species, A. otitis, on the basis of sequence analysis of the 16S rRNA (1). This nomenclature was revised to A. otitidis in keeping with the rules of the Bacteriological Code (21). This study characterizes 19 of these isolates from four geographic locations to (i) determine an adequate growth medium for cultivation, (ii) identify physiological characteristics, (iii) confirm the identities of these isolates by using DNA-DNA homology and a dot blot ...

A 4-h method was devised to differentiate the non-beta-hemolytic streptococci into three categories: enterococci, group D nonenterococci, and viridans streptococci. All of the Streptococcus faecalis, 90% of the Streptococcus faecium (enterococci), and 96% of the Streptococcus bovis biotype I (group D nonenterococci) cultures were correctly identified by the 4-h method. The less commonly isolated group D cultures had lower rates of correct identification by this method. None of the viridans streptococci was identified incorrectly.