Current Microbiology

, Volume 9, Issue 3, pp 155-162

Transfer ofHaemophilus equigenitalis Taylor et al. 1978 to the genusTaylorella gen. nov. asTaylorella equigenitalis comb. nov.

  • Chihiro SugimotoAffiliated withNational Institute of Animal Health
  • , Yasuro IsayamaAffiliated withNational Institute of Animal Health
  • , Riichi SakazakiAffiliated withNational Institute of Health
  • , Shigehiko KuramochiAffiliated withNational Institute of Health

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The taxonomic position ofHaemophilus equigenitalis Taylor et al. 1978, the causative agent of contagious equine metritis, was studied in comparison with phenotypically similar organisms such asMoraxella, Legionella, and others.Haemophilus equigenitalis is a microaerophilic, Gram-negative, nonmotile, short rod; the mean base composition of deoxyribonucleic acid of this organism is 36.5±0.5 mol% G+C. It shows best growth on chocolate agar, but very poor or no growth on plain nutrient agar and blood agar, although it requires no X- or V-factors for the growth. It is positive in catalase, oxidase, phosphatase, and phosphoamidase tests, but very unreactive in other biochemical tests for routine use. It produces no acid from any carbohydrates nor glycosidase. Arylamidase activities of the organism to β-naphtylamide derivatives of various amino acids, and di- and tripeptides were also compared with those of other taxa. The group of this organism was different from other known taxa in the numerical analysis of its phenotypic characteristics, DNA base composition, and DNA-DNA hybridization. These data indicate thatH. equigenitalis does not belong in the genusHaemophilus nor other known genera, but rather in a new genus. Therefore, we propose thatHaemophilus equigenitalis be reclassified in a new genusTaylorella asTaylorella equigenitalis.