Phylum Firmicutes, Class Bacilli, Order Lactobacillales, Family Lactobacillaceae, Genus Lactobacillus, [Group A lactobacilli
(obligately homofermentative), Lactobacillus delbrueckii phylogenetic-group] , Lactobacillus iners Falsen, Pascual, Sjoden, Ohlen
and Collins 1999.
Synonym: Lactobacillus sp. EF (Enevold Falsen) group 47.
Gram-positive rods (0.5-1.5 x 1.5-10 μm) occurring singly, in pairs and in short chains.
After 24 h incubation on blood agar under anaerobic conditions, colonies are small
(less than 1 mm diameter), smooth, translucent, and nonpigmented. Old cultures
display a “fried egg” appearance. No growth on MRS agar or Rogosa agar.
Facultatively anaerobic. No growth at 15 ºC. Can grow at 30 ºC and 42 ºC. Can grow in
1.5% NaCl, but not in 3% NaCl.
Isolated from human clinical specimens (urine, vagina) and medical care products.
Undetermined. May be a normal vaginal inhabitant.
- Hammes W.P. and Hertel C., 2009. Genus I. Lactobacillus Beijerinck 1901. In: (Eds.) P.D. Vos, G. Garrity, D. Jones, N.R. Krieg, W.
Ludwig, F.A. Rainey, K.-H. Schleifer, W.B. Whitman. Bergey’s Manual of Systematic Bacteriology, Volume 3: The Firmicutes,
- Falsen E., Pascual C., Sjoden B., Ohlen M. and Collins M.D., 1999. Phenotypic and phylogenetic characterization of a novel
Lactobacillus species from human sources : description of Lactobacillus iners sp. nov. IJSB 49, 217-221.
- Tell Jakobsson and Urban Forsum. Letter to the Editor: Lactobacillus iners: a Marker of Changes in the Vaginal Flora? J. Clin.
Microbiol. September 2007 45:9 3145; published ahead of print 25 July 2007.
Obligately homofermentative (hexoses are fermented almost exclusively to lactic acid by the Embden-Meyerhof pathway; pentoses or
gluconate are not fermented).
Positive results for hippurate hydrolysis, alanine-phenylalanine-proline arylamidase, esterase C4, alpha-glucosidase, leucine
arylamidase, phosphoamidase, fermentation of glucose without gas production.
Negative results for catalase, aesculin hydrolysys, arginine hydrolysis, gelatin hydrolysis, nitrate reduction, oxidase, urease,
Voges-Proskauer reaction, alkaline phosphatase, chymotrypsin, alpha-fucosidase, alpha-galactosidase, beta-galactosidase,
beta-galacturonidase, beta-glucosidase, beta-glucuronidase, glycyl-tryptophan arylamidase, alpha-mannosidase,
beta-mannosidase, lipase C14, trypsin, fermentation of: arabinose, arabitol, glycogen, N-acetylglucosamine, lactose, mannitol,
melezitose, melibiose, raffinose, rhamnose, ribose, sorbitol, sucrose, tagatose, trehalose, and xylose.
Variable results for maltose fermentation.
(c) Costin Stoica