Moraxella catarrhalis is a bacterium that can live in the human respiratory tract for many years without showing any symptoms. However, in some situations it can become a pathogen. It is responsible, inter alia, for acute otitis media, which is common in children. It is estimated that most young patients are carriers of this microorganism. Moraxella catarrhalis can also cause various infections in immunocompromised adults and the elderly. What diseases does Moraxella catarrhalis cause? When can you catch it? How to treat infections caused by this bacterium?
Moraxella catarrhalisis a bacterium found in the human upper respiratory tract. For many years, doctors and scientists believed that this microbe was their harmless, commensal inhabitant. Commensalism is a form of coexistence of two organisms in which only one gains benefits while not harming the other. In this case, the bacteria lives in the human respiratory tract without adversely affecting he alth.
It turned out, however, thatMoraxella catarrhaliscan cause acute otitis media in children. This bacterium can also be dangerous for patients suffering from chronic obstructive pulmonary disease. In these people, it can cause recurrent, chronic respiratory infections.
Moraxella catarrhalisis an aerobic bacterium that is part of the physiological flora of the mucous membranes. It belongs to the group of Gram-negative microbes, which means that it has two cell membranes: outer and cytoplasmic.
AdditionallyMoraxella catarrhalisis covered with a mucous shell that protects it from external factors. Due to the shape of the colonies it creates, it is classified as a split.
Contents:
- Pathogenicity Moraxella catarrhalis
- Respiratory colonization by Moraxella catarrhalis
- Ability of Moraxella catarrhalis to form biofilm
- Moraxella catarrhalis - antibiotic therapy
- Moraxella catarrhalis as a threat to children's he alth
- Moraxella catarrhalis acute otitis media
- Moraxella catarrhalis infections in adults
- Moraxella catarrhalis and nosocomial infections
- What determines thethe virulence of Moraxella catarrhalis?
- Drug resistance Moraxella catarrhalis
- Moraxella catarrhalis - diagnostic tests
Pathogenicity Moraxella catrrhalis
Moraxella catarrhalisis an opportunistic bacterium. This means that it can settle in the host's body without causing any symptoms. The pathogen is visibly activated when the immune system is weakened. Carriers may unknowingly pass the bacterium on to people around them.
Commensal formMoraxella catarrhalisoccurs very often in children. This pathogen is carried by up to 75% of young patients. These bacteria most often inhabit the nasopharynx. In the case of adults, only about 5% of the population is carriers.
In recent years,Moraxella catarrhalishas been treated more and more seriously as a threat by doctors and scientists. It is currently believed to be the cause of bronchopulmonary infections.
This bacterium is responsible for many cases of pneumonia in adults with compromised immune systems.
Children are especially vulnerable to attacksMoraxella catarrhalis . In their case, acute otitis media occurs most often. This bacterium can also cause the following diseases in patients:
- acute sinusitis
- maxillary sinusitis
- bacteremia
- meningitis
- conjunctivitis
- acute purulent bronchitis
- urethritis
- septic arthritis
- acute laryngitis
Respiratory colonization by Moraxella catarrhalis
Colonization of the upper respiratory tract by Moraxella catarrhalis is extremely common in children. In adults, this problem is rare. There are also factors other than age that increase the likelihood of carrying this bacterium. These include:
- living in densely populated places
- low social status
- genetic predisposition
Most adults who are carriers ofMoraxella catarralis suffer from COPD (Chronic Obstructive Pulmonary Disease) or another respiratory disease.
Situations conducive to colonization of the respiratory tract byMoraxella catarralisis attending kindergartens and nurseries, as well as hospitalization in multi-person rooms.
Ability of Moraxella catarrhalis to form biofilm
Biofilm is a multicellular structure made of bacteria surrounded by a layerthe substances they produce. Thanks to the creation of this form, microorganisms show greater resistance to antibiotics and the immune mechanisms of our body.
Biofilm is able to adhere to biological surfaces, such as teeth, and artificial surfaces, such as implants. This structure is sometimes metaphorically described as "the city of microbes".
Biofilm formation is an important step in the colonization of our body byMoraxella catarrhalis . It allows bacteria to survive in the respiratory tract for a long time. It also protects them from the immune response and administered medications.
Moraxella catarrhalis - antibiotic therapy
In the treatment of infections caused byMoraxella catarrhalis , the following is used:
- kotrimoxazole
- higher generation cephalosporins
- penicillin in combination with an inhibitor
- tetracyclines
- quinolones
- amoxicillin with clavulanic acid
- macrolides
Moraxella catarrhalis as a threat to children's he alth
Moraxella catarrhalisis an important pathogen causing infections in children. This is because their immune systems are just developing. In adults, diseases related to the activity of this bacterium usually occur as a result of severe weakening of the body.
In children, the most common illnesses ofMoraxella catarrhalisare acute otitis media and sinusitis. Cases of pneumonia are rare. Typically, this type of infection is associated with a child's immunodeficiency.
Moraxella catarrhalis acute otitis media
Acute otitis media (AOM) is a common childhood disease. It is the most common reason for the use of antibiotics in patients in this age group. Infants and children up to 3 years of age are the most exposed to AOM. It is related to the immaturity of their immune system. It is estimated that as many as 80% of children experience an episode of this disease before their third birthday.
The most common bacteria causing acute otitis media in children are:
- M.catarrhalis
- Streptococcus pneumoniae
- Haemophilus influenzae
At the same time, it has been proven that the colonization of the child's oropharynx byMoraxella catarrhalisis a factor increasing the likelihood of developing AOM.
Symptoms of acute otitis media:
- throbbing ear pain of high intensity
- purulentdischarge from the ear
- fever
- headache
- hearing problems
- loss of appetite
- weakness
Proper diagnosis requires consultation with a specialist doctor. If a child is diagnosed with AOM, antibiotics are usually required.
Moraxella catarrhalis infections in adults
Infections with the bacterium M. catarrhalis in the respiratory system in adults take various clinical forms. The most important are:
- laryngitis
- exacerbation of chronic obstructive pulmonary disease
- pneumonia
- nosocomial respiratory tract infections
These types of infections usually affect immunocompromised patients and the elderly.
Moraxella catarrhalis and nosocomial infections
There are many known cases of in-hospital outbreaks caused by M.catarrhalis . There are certain risk factors that increase the likelihood of this bacteria spreading in the hospital setting. The meanings are:
- multi-bed sale
- long hospitalization
- contamination of hospital space
Moraxella catarralishas been tested to survive for 3 weeks in a sputum sample. Therefore, this pathogen can persist on hospital surfaces for quite a long time, infecting other patients.
What determines the virulence of Moraxella catarrhalis?
Research has shown thatMoraxella catarrhalishas the ability to colonize the respiratory tract and middle ear mucosa. This is possible due to the numerous receptors that bind to elements of the host epithelium. These bacteria also have the ability to penetrate inside human cells. Thanks to this, being inside them, they avoid the immune response of our body.
Moraxella catarrhalisalso demonstrates the ability to compete with the physiological commensal bacterial flora of the respiratory tract. It can multiply and develop with reduced access to nutrients. Under such conditions, it gains an advantage over other microorganisms. This bacterium then creates microcolonies and a biofilm.
Drug resistance Moraxella catarrhalis
M.catarrhalisshows high sensitivity to most antibiotics used to treat respiratory infections. However, innate resistance of these microorganisms to penicillin, vancomycin, trimethoprim and clindamycin has been documented.
CommonMoraxella catarralisresistance to penicillin is due to the ability of this bacterium to produce β-lactamases. First strainshowing this type of drug resistance was detected in Sweden in 1977. Since then, the percentage of microorganisms belonging toMoraxella catarralisexhibiting resistance to penicillin has increased rapidly. It is currently estimated that the β-lactamase-producing capacity is over 90% of M.catarrhalis .
Beta-lactamases are enzymes produced by bacteria. These proteins have the ability to break the beta-lactam bond in the molecules of some antibiotics. Thanks to their action, microorganisms are insensitive to certain groups of drugs.
A method of stopping bacteria from resisting penicillin is by combining this antibiotic with a β-lactamase inhibitor. These substances block the action of the anti-bacterial enzymeMoraxella catarralison drugs.
Moraxella catarrhalis - diagnostic tests
In order to diagnose the infection caused byMoraxella catarrhalis , usually a swab is made and then the bacteria are cultured. Unfortunately, its external resemblance toNeisseriaoften causes diagnostic problems.
In order to start the proper treatment with antibiotics, it is recommended to perform an antibiogram. This test is effective in determiningMoraxella catarrhalissusceptibility to specific medications.
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Sara Janowska, MA in pharmacyPhD student of interdisciplinary doctoral studies in the field of pharmaceutical and biomedical sciences at the Medical University of Lublin and the Institute of Biotechnology in Białystok. A graduate of pharmaceutical studies at the Medical University of Lublin with a specialization in Plant Medicine. She obtained a master's degree defending a thesis in the field of pharmaceutical botany on the antioxidant properties of extracts obtained from twenty species of mosses. Currently, in his research work, he deals with the synthesis of new anti-cancer substances and the study of their properties on cancer cell lines. For two years she worked as a master of pharmacy in an open pharmacy.
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