| Haemophilus aegyptius |
Taxonomy
Morphology
Cultural characteristics
Biochemical characters
Ecology
Pathogenicity
References
Phylum Proteobacteria, Class Gammaproteobacteria, Order Pasteurellales, Family Pasteurellaceae, Genus Haemophilus,
Haemophilus aegyptius (Trevisan 1889) Pittman and Davis 1950.
Historical synonyms: Bacillus aegyptius Trevisan 1889, Bacillus conjunctivitidis Kruse 1896, Bacterium conjunctivitis Chester 1897,
Bacterium pseudo conjunctivitidis (Kruse) Chester 1897, Bacterium aegyptiacum Lehmann and Neumann 1899, Hemophilus
conjunctivitidis (Kruse) Bergey et al. 1923. Common name: Koch-Weeks Bacillus.
Haemophilus aegyptius (Trevisan 1889) Pittman and Davis 1950.
Historical synonyms: Bacillus aegyptius Trevisan 1889, Bacillus conjunctivitidis Kruse 1896, Bacterium conjunctivitis Chester 1897,
Bacterium pseudo conjunctivitidis (Kruse) Chester 1897, Bacterium aegyptiacum Lehmann and Neumann 1899, Hemophilus
conjunctivitidis (Kruse) Bergey et al. 1923. Common name: Koch-Weeks Bacillus.
Gram-negative, 0.2-0.3 / 2.0-3.0 µm, piliated, long slender rods, nonmotile,
nonsporeforming. Capsules have not been demonstrated.
nonsporeforming. Capsules have not been demonstrated.
Growth of freshly isolated strains on chocolate agar is slow; colonies are smooth,
low, convex, grayish, translucent, 0.5 mm in diameter in 48h. Forms comet-like
colonies in semisolid agar media. Hemolysis is negative.
Does not grow on Tryptic soy agar Difco with X and V factors added , in contrast to
Haemophilus influenzae. Aerobic, facultatively anaerobic, requires X-factor and
V-factor for growth. CO2 is not required. Optimum temperature 34-37 ºC. Growth on
MacConkey agar was not determined.
low, convex, grayish, translucent, 0.5 mm in diameter in 48h. Forms comet-like
colonies in semisolid agar media. Hemolysis is negative.
Does not grow on Tryptic soy agar Difco with X and V factors added , in contrast to
Haemophilus influenzae. Aerobic, facultatively anaerobic, requires X-factor and
V-factor for growth. CO2 is not required. Optimum temperature 34-37 ºC. Growth on
MacConkey agar was not determined.
Causes acute or subacute infectious conjunctivitis in hot climates. It has not been demonstrated in healthy individuals. Humans are
the only natural host .
the only natural host .
Produce an extracellular IgA1-cleaving endopeptidase and have neuraminidase activity. Is piliated. Have hemagglutinating activity.
Causes acute or subacute infectious conjunctivitis in hot climates.
“BPF clones” closely related to H. aegyptius (H. influenzae biogroup aegyptius) have been associated with Brazilian purpuric fever.
Presents low experimental pathogenicity for mouse and higher for 8-days chicken embryos.
Causes acute or subacute infectious conjunctivitis in hot climates.
“BPF clones” closely related to H. aegyptius (H. influenzae biogroup aegyptius) have been associated with Brazilian purpuric fever.
Presents low experimental pathogenicity for mouse and higher for 8-days chicken embryos.
- Mogens Kilian, 2004. Genus III. Haemophilus. In: Bergey’s Manual of Systematic Bacteriology, Second edition, Vol two, part B,
George M. Garrity (Editor-in-Chief), pp. 883-904. - Mary P.E. Slack, 2006. Haemophilus. In: Topley & Wilson’s Microbiology and Microbial Infections, 10th edition, Vol. 2, Bacteriology,
Edward Arnold Ltd. - Pozsgi N., 1985. Genul Pasteurella. In: Bacteriologie medicala, vol II, V. Bilbiie, N. Pozsgi (sub redactia), Ed. Medicala, Bucuresti,
123-130. - Margaret Pittman & Dorland J. Davis: IDENTIFICATION OF THE KOCH-WEEKS BACILLUS (HEMOPHILUS AEGYPTIUS). J.
Bacteriol. 59 (3): 413.
Positive results for nitrates reduction, oxidase, alkaline phosphatase, catalase and urease. Acid production from D(+) glucose, D(+)
galactose and maltose is weak.
Negative results for H2S production, arginine dehydrolase, lysine decarboxylase, ornithine decarboxylase, indole production,
alpha-glucosidase, gas production from D-glucose, acid production from: glycerol, xylitol, L(+) arabinose, dulcitol, meso-inositol,
mannitol, D(-) sorbitol, D(-) fructose, D(+) mannose, L(+) rhamnose, L(-) sorbose, cellobiose, lactose, D(+) melibiose, sucrose
(saccharose), trehalose, raffinose, inulin, D(+) xylose, esculin and salicin.
galactose and maltose is weak.
Negative results for H2S production, arginine dehydrolase, lysine decarboxylase, ornithine decarboxylase, indole production,
alpha-glucosidase, gas production from D-glucose, acid production from: glycerol, xylitol, L(+) arabinose, dulcitol, meso-inositol,
mannitol, D(-) sorbitol, D(-) fructose, D(+) mannose, L(+) rhamnose, L(-) sorbose, cellobiose, lactose, D(+) melibiose, sucrose
(saccharose), trehalose, raffinose, inulin, D(+) xylose, esculin and salicin.
(c) Costin Stoica
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