Moraxella catarrhalis Infection Clinical Presentation

Updated: Mar 22, 2021
  • Author: Michael Constantinescu, MD; Chief Editor: Michael Stuart Bronze, MD  more...
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History and Physical Examination

The history typically suggests the type of infection present (eg, upper respiratory tract infection [URTI], lower respiratory tract infection [LRTI], bacteremia, or endocarditis). Physical findings in M catarrhalis infections are similar to findings of infections with other organisms in the same location.

Common cold

In 29% of common-cold episodes due to bacterial pathogens (including M catarrhalis), affected children continued to be symptomatic 10 days after the first appearance of symptoms. [3]

Otitis media

A clinical history of acute otitis media and otitis media with effusion with symptoms includes otalgia, fever, and hearing loss. Otitis media is a very common condition, especially in children. Approximately 70% of children experience at least 1 episode of otitis media during childhood. M catarrhalis has been isolated in 3-17.3% of middle ear exudates in children with otitis media. [4, 5]


In a patient with sinusitis, the clinical history commonly includes headache, pain in the maxillary or frontal area, fever, and cough. Young children present with persistent nasal discharge (lasting longer than 2 weeks) and cough, especially at night. M catarrhalis has been isolated in 22% of maxillary sinus aspirates in children as a single pathogen and in 72% of aspirates in combination with other organisms (eg, S pneumoniae or H influenzae). [6]

Lower respiratory tract infection

In adult patients who have a history of conditions such as chronic obstructive pulmonary disease (COPD), pneumoconiosis, asthma, malignancies, or immunosuppression and who show findings characteristic of bronchitis or pneumonia or exacerbations of their underlying condition, M catarrhalis infection is a possibility. M catarrhalis LRTI is also associated with smoking. M catarrhalis is isolated from sputum and transtracheal aspirate specimens at rates of 0.2-8.1%, accompanied by H influenzae and/or S pneumoniae in more than 30% of cases. [7, 8, 9, 10]

In children, LRTIs have been associated with a history of recent respiratory syncytial virus or cytomegalovirus infection or with more debilitating conditions, such as bronchopulmonary dysplasia, ventricular septal defect, leukemia, Arnold-Chiari syndrome, prematurity, or HIV infection. [11, 12]

Nosocomial infections

Outbreaks of nosocomial infections with M catarrhalis have been reported, mostly involving pulmonary units or pediatric intensive care units (PICUs).


In 46% of patients with M catarrhalis bacteremia, no primary site of infection is found. Bacteremia is rare with M catarrhaliscommunity-acquired pneumonia. [13] The following conditions have been found to predispose to M catarrhalis bacteremia:

Endocarditis and other local infections

M catarrhalisendocarditis has been described in patients with a history of valvular conditions or prostheses, as well as in patients who were previously healthy. It has also been described as a complication of balloon angioplasty. [14, 15] M catarrhalis has been identified as a pathogen in cleft palate repairs (resulting in a higher fistula rate). [16] Sporadic cases of other infections with M catarrhalis include the following:

  • Meningitis

  • Neonatal ophthalmia

  • Septic arthritis

  • Urinary tract infection

  • Wound infection

  • Peritonitis in patients on dialysis

  • Periorbital cellulitis [17]

  • Acute urethritis resembling gonorrhea [18]



Complications of M catarrhalis infection may include the following:

  • Recurrence

  • Bacteremia and sepsis

  • Meningitis

  • Mastoiditis

  • Hearing loss

  • Pleural effusion

  • Shock

  • Death