An Unclassified Gram-Negative Rod Isolated From the Pharynx on Thayer-Martin Medium (Selective Agar)

Abstract

An oxidase-positive, small gram-negative rod was isolated on Thayer-Martin medium (TM) inoculated with pharyngeal swabs obtained during surveys to detect Neisseria carriers. In one survey, this organism was isolated from 48% of the subjects, and 50 or more colonies were present on the majority of the primary isolation plates. Other characteristics of the organism, which has been given the provisional designation "TM-1," include: delayed production (2 to 10 days) of acid from glucose, formation of gas during nitrate reduction, and the frequent formation of "pits" in the agar surface. On TM, nonpitting colonies of TM-1 are morphologically similar to colonies of Neisseria gonorrhoeae and N. kactamica. Comparison of the characteristics of TM-1 strains with other similar fastidious gram-negative organisms encountered in clinical laboratories indicates that TM-1 is a distinct species. Further studies are required before proper taxonomic placement can be made. During a survey to determine the pharyngeal carrier rates of Neisseria meningitidis and N.

Reduction of nitrogenous oxides by microorganisms.

“…Finally, an unidentified gram-negative bacterium quite like Moraxella kingii is isolated on occasion from pharyngeal and urinary sources on media selective for Neisseria. The capacity of this isolate for denitrification sharply distinguishes it from other related bacteria (131).…”

“…Denitrification. Bacterial isolates reported to be members of the genera listed in Table 2 are known to release nitrogen (or nitrous oxide) by respiratory nitrate reduction (81,131,225,323,343,354,393). The property fits poorly with other physiological aspects of certain of these (e.g., the bacilli), and Verhoeven (377) thus suggests a new genus, Denitrobacillus, to accommodate the species he considers unique, Bacillus licheniformis.…”

Differentiation of Kingella denitrificans from Neisseria gonorrhoeae by growth on a semisolid medium and sensitivity to amylase

“…Incubation was for 48 h at 35°C in an atmosphere of 5% CO2. NOTES 391 is unknown, its high prevalence (48%) in upper respiratory tract specimens (2,5) may complicate diagnostic procedures for identifying N. gonorrhoeae. Therefore, reliable laboratory techniques for distinguishing these microorganisms are necessary.…”

Comparison of a slide coagglutination technique with the Minitek system for confirmation of Neisseria gonorrhoeae

“…TM-1 and Gemella haemolysans (formerly N. haemolysans) isolates were included as organisms that are frequently encountered in the pharynx and other mucosal membranes and demonstrate Gram reactions similar to those of N. gonorrhoeae (10,19,22). In addition, TM-1 isolates have cultural characteristics, colony morphology, oxidase production, and biochemical reactions similar to those for N. gonorrhoeae (10,19). Acinetobacter species may mimic N. gonorrhoeae upon Gram reaction or possess similar cultural characteristics (18,19).…”