Haemophilus influenzae: Difference between revisions

Latest revision as of 17:25, 12 January 2024

Background

Microbiology

Species of Gram-negative bacillus within the genus Haemophilus
Deficient heme biosynthetic pathway leading to X-factor-dependent growth on media
Fastidious growth with standard media
May be encapsulated; non-encapsulated strains are referred to as "nontypeable"
The group includes Haemophilus influenzae, Haemophilus aegyptius, and Haemophilus haemolyticus

Test	Biotype
Test	I	II	III	IV	V	VI	VII	VIII
Indole	+	+	–	–	+	–	+	+
Urease	+	+	+	+	–	–	–	–
ODC	+	–	–	+	+	+	–	–

Clinical Manifestations

Community-acquired pneumonia, particularly in children, meningitis, bacteremia, mainly type b strains
Community-acquired pneumonia, acute otitis media, acute sinusitis, acute exacerbation of COPD, mainly untypeable strains

Management

For beta-lactamase-negative strains, ampicillin is recommended
For beta-lactamase-positive strains, ceftriaxone or cefepime
Alternatives include chloramphenicol, ertapenem, meropenem
Possibly also a fluoroquinolone, azithromycin, clarithromycin, doxycycline, amoxicillin-clavulanic acid
Duration depends on syndrome being treated:
- Uncomplicated meningitis: 10 days
- Pneumonia: at least 5 days, with clinical improvement
- Septic arthritis: 10 to 14 days
- Pericarditis: 3 to 6 weeks
- Empyema: 3 to 6 weeks
- Osteomyelitis: 3 to 6 weeks

@@ Line 3: / Line 3: @@
 * Species of [[Stain::Gram-negative]] [[Shape::bacillus]] within the genus [[Genus::Haemophilus]]
 * Deficient heme biosynthetic pathway leading to X-factor-dependent growth on media
+* Fastidious growth with standard media
+* May be encapsulated; non-encapsulated strains are referred to as "nontypeable"
 * The group includes ''Haemophilus influenzae'', [[Haemophilus aegyptius]], and [[Haemophilus haemolyticus]]
 {{DISPLAYTITLE:''Haemophilus influenzae''}}
+{| class="wikitable"
-[[Category::Gram-negative bacilli]]
+! rowspan="2" |Test
+! colspan="8" |Biotype
+|-
+!I
+!II
+!III
+!IV
+!V
+!VI
+!VII
+!VIII
+|-
+|Indole
+| +
+| +
+|–
+|–
+| +
+|–
+| +
+| +
+|-
+|Urease
+| +
+| +
+| +
+| +
+|–
+|–
+|–
+|–
+|-
+|ODC
+| +
+|–
+|–
+| +
+| +
+| +
+|–
+|–
+|}
+== Clinical Manifestations ==
+* [[Community-acquired pneumonia]], particularly in children, [[meningitis]], [[bacteremia]], mainly type b strains
+* [[Community-acquired pneumonia]], [[acute otitis media]], [[acute sinusitis]], [[acute exacerbation of COPD]], mainly untypeable strains
+== Management ==
+* For beta-lactamase-negative strains, [[ampicillin]] is recommended
+* For beta-lactamase-positive strains, [[ceftriaxone]] or [[cefepime]]
+* Alternatives include [[chloramphenicol]], [[ertapenem]], [[meropenem]]
+* Possibly also a [[Fluoroquinolones|fluoroquinolone]], [[azithromycin]], [[clarithromycin]], [[doxycycline]], [[amoxicillin-clavulanic acid]]
+* Duration depends on syndrome being treated:
+** Uncomplicated [[Bacterial meningitis|meningitis]]: 10 days
+** [[Community-acquired pneumonia|Pneumonia]]: at least 5 days, with clinical improvement
+** [[Septic arthritis]]: 10 to 14 days
+** [[Pericarditis]]: 3 to 6 weeks
+** [[Empyema]]: 3 to 6 weeks
+** [[Osteomyelitis]]: 3 to 6 weeks
+== Further Reading ==
+* Antimicrobial Resistance in ''Haemophilus influenzae''. ''Clin Microbiol Rev''. 2007. doi: [https://doi.org/10.1128/CMR.00040-06 10.1128/CMR.00040-06]
+[[Category:Gram-negative bacilli]]