Mobiluncus

Abstract

Mo.bi.lun'cus. L. adj. mobilis capable of movement, active; L. masc. n. uncus hook; N.L. masc. n. Mobiluncus a motile curved rod. Actinobacteria / Actinobacteria / Actinomycetales / Actinomycetaceae / Mobiluncus Curved rods with tapered ends, 1–5 × 0.4–0.6 µm. Depending on the growth medium, cells occur singly or in pairs with a gullwing appearance. Gram‐stain‐negative or Gram‐stain‐variable . Cells are motile by means of multiple subpolar flagella (exact numbers are yet to be determined, but are thought to be between one and eight), and possess a multi‐layered Gram‐stain‐positive cell‐wall type. Endospores are not formed . Anaerobic , growing best in an enriched CO 2 atmosphere. Some strains become aerotolerant after several passages, being able to grow in a partially reduced atmosphere containing 5% O 2 . Optimum growth at 35–37°C, with no or poor growth at 20, 43, or 45°C. Growth is stimulated by horse or rabbit serum and by whole blood. Growth is not stimulated by formate/fumarate. Slow growth on solid media. After 3 d incubation at 37°C, colonies on peptone/yeast extract/glucose/sheep blood or Columbia agar supplemented with human blood are pin‐point to 1 mm in diameter. After 5 d, the colonies are larger, 1–2.5 mm in diameter, and gray‐white or slightly yellowish. Cells are killed by heating at 55°C for 15 minutes. Oxidase‐ and catalase‐negative. Weakly (terminal pH 5.5–6.5) or strongly (terminal pH <5.5) saccharolytic. Fermentation products include acetic and succinic acids, with or without lactic acid, when grown in peptone/yeast extract/glucose medium. Propionic acid is not produced. Do not produce acid from L ‐arabinose, D ‐arabitol, lactose, mannitol, methyl‐β‐ D ‐galactopyranoside, or sorbitol. Negative for alkaline phosphatase, α‐arabinosidase, chymotrypsin, β‐galactosidase‐6‐phosphate, β‐glucosidase, trypsin, and urease (RapID 32Strep), cysteine arylamidase, lipase (C14), α‐mannosidase, β‐mannosidase, N ‐acetyl‐β‐glucosaminidase, glutamyl glutamic acid arylamidase, pyroglutamic acid, and valine arylamidase activity. Variable activity for phenylalanine arylamidase (weak‐ to strong‐positive reaction). Acid phosphatase‐ and pyrollydonyl arylamidase‐negative. Acetoin is not produced . Gelatin is not hydrolyzed. Nitrate may be reduced . Sensitive to ampicillin, cefazolin, cefoxitin, cephalothin, clindamycin, gentamicin, imipenem, moxalactam, penicillin G, rifampin, streptomycin, tobramycin, vancomycin, and virginiamycin. Resistant to colistin, cycloserine, nalidixic acid, neomycin, and mezlocillin. Associated with the human vaginal flora and bacterial vaginosis (BV). DNA G+C content (mol%) : 49–52 ( T m ; Spiegel and Roberts, 1984a); 50–54 ( T m ; Hammann et al., 1984). Type species : Mobiluncus curtisii Spiegel and Roberts 1984a, 181 VP .