Moraxella catarrhalis

Background

• Gram negative diploccocus
• Common cause of pneumonia, otitis media, and sinusitis

Differential Diagnosis

Causes of Pneumonia

Bacteria

• Gram-positive
  • Streptococcus pneumoniae
  • Staphylococcus aureus
• Gram-negative
  • Haemophilus influenzae
  • Klebsiella pneumoniae
  • Escherichia coli
  • Pseudomonas aeruginosa
  • Moraxella catarrhalis
• Atypical pneumonia
  • Chlamydophila pneumoniae
  • Chlamydophila psittaci
  • Mycoplasma pneumoniae
  • Coxiella burnetti
  • Legionella pneumophila

Viral

• Common
  • Influenza
  • Respiratory syncytial virus
  • Parainfluenza
• Rarer
  • Adenovirus
  • Metapneumovirus
  • Severe acute respiratory syndrome (SARS)
  • Middle east respiratory syndrome coronavirus (MERS)
  • 2019-nCoV (COVID-19)
• Cause other diseases, but sometimes cause pneumonia
  • Herpes simplex virus
  • Varicella-zoster (VZV)
  • Measles
  • Rubella
  • Cytomegalovirus
  • Smallpox
  • Dengue

Fungal

• Histoplasmosis
• Coccidioidomycosis
• Blastomycosis
• Pneumocystis jirovecii pneumonia (PCP)
• Sporotrichosis
• Cryptococcosis
• Aspergillosis
• Candidiasis

Parasitic

• Ascariasis
• Schistosomiasis
• Toxoplasma gondii

Antibiotic Sensitivities

Category	Antibiotic	Sensitivity
Penicillins	Penicillin G	R
	Penicillin V	R
Anti-Staphylocccal Penicillins	Methicillin	R
	Nafcillin/Oxacillin	R
	Cloxacillin/Diclox.	R
Amino-Penicillins	AMP/Amox	R
	Amox-Clav	S
	AMP-Sulb	S
Anti-Pseudomonal Penicillins	Ticarcillin	R
	Ticar-Clav	S
	Pip-Tazo	S
	Piperacillin	I
Carbapenems	Doripenem	S
	Ertapenem	S
	Imipenem	S
	Meropenem	S
	Aztreonam	S
Fluroquinolones	Ciprofloxacin	S
	Ofloxacin	S
	Pefloxacin	S
	Levofloxacin	S
	Moxifloxacin	S
	Gemifloxacin	S
	Gatifloxacin	S
1st G Cephalo	Cefazolin	I
2nd G. Cephalo	Cefotetan	S
	Cefoxitin	S
	Cefuroxime	S
3rd/4th G. Cephalo	Cefotaxime	S
	Cefizoxime	S
	CefTRIAXone	S
	Ceftaroline	S
	CefTAZidime	S
	Cefepime	S
Oral 1st G. Cephalo	Cefadroxil	R
	Cephalexin	R
Oral 2nd G. Cephalo	Cefaclor/Loracarbef	I
	Cefproxil	S
	Cefuroxime axetil	S
Oral 3rd G. Cephalo	Cefixime	S
	Ceftibuten	S
	Cefpodox/Cefdinir/Cefditoren	S
Aminoglycosides	Gentamicin	S
	Tobramycin	S
	Amikacin	S
	Chloramphenicol	S
	Clindamycin	R
Macrolides	Erythromycin	I
	Azithromycin	S
	Clarithromycin	S
Ketolide	Telithromycin	S
Tetracyclines	Doxycycline	S
	Minocycline	S
Glycylcycline	Tigecycline	S
	Daptomycin	R
Glyco/Lipoclycopeptides	Vancomycin	X1
	Teicoplanin	X1
	Telavancin	X1
	Fusidic Acid	X1
	Trimethoprim	X1
	TMP-SMX	S
Urinary Agents	Nitrofurantoin	X1
	Fosfomycin	X1
Other	Rifampin	S
	Metronidazole	R
	Quinupristin dalfoppristin	S
	Linezolid	I
	Colistimethate	X1

Key

• S susceptible/sensitive (usually)
• I intermediate (variably susceptible/resistant)
• R resistant (or not effective clinically)
• S+ synergistic with cell wall antibiotics
• U sensitive for UTI only (non systemic infection)
• X1 no data
• X2 active in vitro, but not used clinically
• X3 active in vitro, but not clinically effective for Group A strep pharyngitis or infections due to E. faecalis
• X4 active in vitro, but not clinically effective for strep pneumonia

See Also

• Microbiology (Main)

External Links

CDC: Moraxella catarrhalis