Moraxella catarrhalis

Last updated

Moraxella catarrhalis
Scientific classification
Kingdom:
Phylum:
Class:
Order:
Family:
Genus:
Species:
M. catarrhalis
Binomial name
Moraxella catarrhalis
(Frosch and Kolle 1896) Henriksen and Bøvre 1968 [1]

Moraxella catarrhalis is a fastidious, nonmotile, Gram-negative, aerobic, oxidase-positive diplococcus that can cause infections of the respiratory system, middle ear, eye, central nervous system, and joints of humans. It causes the infection of the host cell by sticking to the host cell using trimeric autotransporter adhesins.

Aerobic organism

An aerobic organism or aerobe is an organism that can survive and grow in an oxygenated environment. In contrast, an anaerobic organism (anaerobe) is any organism that does not require oxygen for growth. Some anaerobes react negatively or even die if oxygen is present.

Oxidase test microbiological and biochemical method for identification

The oxidase test is a test used in microbiology to determine if a bacterium produces certain cytochrome c oxidases. It uses disks impregnated with a reagent such as N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD) or N,N-dimethyl-p-phenylenediamine (DMPD), which is also a redox indicator. The reagent is a dark-blue to maroon color when oxidized, and colorless when reduced. Oxidase-positive bacteria possess cytochrome oxidase or indophenol oxidase. These both catalyze the transport of electrons from donor compounds (NADH) to electron acceptors . The test reagent, TMPD dihydrochloride acts as an artificial electron donor for the enzyme oxidase. The oxidized reagent forms the colored compound indophenol blue. The cytochrome system is usually only present in aerobic organisms that are capable of using oxygen as the terminal electron acceptor. The end-product of this metabolism is either water or hydrogen peroxide.

A diplococcus is a round bacterium that typically occurs in the form of two joined cells. Examples of gram-negative diplococci are Neisseria spp., Moraxella catarrhalis, and Acinetobacter spp. Examples of gram-positive diplococci are Streptococcus pneumoniae and Enterococcus spp.

Contents

Epidemiology

M. catarrhalis is a human pathogen with an affinity for the human upper respiratory tract. Other primates, such as macaques, might become infected by this bacterium. [2]

History

M. catarrhalis was previously placed in a separate genus named Branhamella . The rationale for this was that other members of the genus Moraxella are rod-shaped and rarely caused infections in humans. However, results from DNA hybridization studies and 16S rRNA sequence comparisons were used to justify inclusion of the species M. catarrhalis in the genus Moraxella. [3] As a consequence, the name Moraxella catarrhalis is currently preferred for these bacteria. Nevertheless, some in the medical field continue to call these bacteria Branhamella catarrhalis.

The only species of Branhamella is reclassified to Moraxella catarrhalis.

Moraxella is a genus of Gram-negative bacteria in the Moraxellaceae family. It is named after the Swiss ophthalmologist Victor Morax. The organisms are short rods, coccobacilli, or as in the case of Moraxella catarrhalis, diplococci in morphology, with asaccharolytic, oxidase-positive, and catalase-positive properties. M. catarrhalis is the clinically most important species under this genus.

Bacilli taxon (class) Bacilli, including some rod-shaped (bacilli) and some spherical (cocci) bacteria

Bacilli is a taxonomic class of bacteria that includes two orders, Bacillales and Lactobacillales, which contain several well-known pathogens such as Bacillus anthracis. Bacilli are almost exclusively gram-positive bacteria.

Moraxella is named after Victor Morax, a Swiss ophthalmologist who first described this genus of bacteria. Catarrhalis is derived from catarrh, from the Greek meaning "to flow down" (cata- implies down; -rrh implies flow), describing the profuse discharge from eyes and nose typically associated with severe inflammation in colds.

Victor Morax French and Swiss ophthalmologist

Victor Morax was a Swiss ophthalmologist born in Morges, Switzerland.

Catarrh is inflammation of the mucous membranes in one of the airways or cavities of the body, usually with reference to the throat and paranasal sinuses. It can result in a thick exudate of mucus and white blood cells caused by the swelling of the mucous membranes in the head in response to an infection. It is a symptom usually associated with the common cold, pharyngitis, and chesty coughs, but it can also be found in patients with adenoiditis, otitis media, sinusitis or tonsillitis. The phlegm produced by catarrh may either discharge or cause a blockage that may become chronic.

Greek language language spoken in Greece, Cyprus and Southern Albania

Greek is an independent branch of the Indo-European family of languages, native to Greece, Cyprus and other parts of the Eastern Mediterranean and the Black Sea. It has the longest documented history of any living Indo-European language, spanning more than 3000 years of written records. Its writing system has been the Greek alphabet for the major part of its history; other systems, such as Linear B and the Cypriot syllabary, were used previously. The alphabet arose from the Phoenician script and was in turn the basis of the Latin, Cyrillic, Armenian, Coptic, Gothic, and many other writing systems.

Genetics

The whole genome sequence of M. catarrhalis CCUG 353 type strain was deposited and published in DNA Data Bank of Japan, European Nucleotide Archive, and GenBank in 2016 under the accession number LWAH00000000. [4]

Genome entirety of an organisms hereditary information; genome of organism (encoded by the genomic DNA) is the (biological) information of heredity which is passed from one generation of organism to the next; is transcribed to produce various RNAs

In the fields of molecular biology and genetics, a genome is the genetic material of an organism. It consists of DNA. The genome includes both the genes and the noncoding DNA, as well as mitochondrial DNA and chloroplast DNA. The study of the genome is called genomics.

The DNA Data Bank of Japan (DDBJ) is a biological database that collects DNA sequences. It is located at the National Institute of Genetics (NIG) in the Shizuoka prefecture of Japan. It is also a member of the International Nucleotide Sequence Database Collaboration or INSDC. It exchanges its data with European Molecular Biology Laboratory at the European Bioinformatics Institute and with GenBank at the National Center for Biotechnology Information on a daily basis. Thus these three databanks contain the same data at any given time.

European Nucleotide Archive Online database from the EBI on Nucleotides

The European Nucleotide Archive (ENA) is a repository providing free and unrestricted access to annotated DNA and RNA sequences. It also stores complementary information such as experimental procedures, details of sequence assembly and other metadata related to sequencing projects. The archive is composed of three main databases: the Sequence Read Archive, the Trace Archive and the EMBL Nucleotide Sequence Database. The ENA is produced and maintained by the European Bioinformatics Institute and is a member of the International Nucleotide Sequence Database Collaboration (INSDC) along with the DNA Data Bank of Japan and GenBank.

Clinical significance

These bacteria are known to cause otitis media, [5] [6] bronchitis, sinusitis, and laryngitis. Elderly patients and long-term heavy smokers with chronic obstructive pulmonary disease should be aware that M. catarrhalis is associated with bronchopneumonia, as well as exacerbations of existing chronic obstructive pulmonary disease.

Otitis media otitis which involves inflammation of the middle ear

Otitis media is a group of inflammatory diseases of the middle ear. The two main types are acute otitis media (AOM) and otitis media with effusion (OME). AOM is an infection of rapid onset that usually presents with ear pain. In young children this may result in pulling at the ear, increased crying, and poor sleep. Decreased eating and a fever may also be present. OME is typically not associated with symptoms. Occasionally a feeling of fullness is described. It is defined as the presence of non-infectious fluid in the middle ear for more than three months. Chronic suppurative otitis media (CSOM) is middle ear inflammation of greater than two weeks that results in episodes of discharge from the ear. It may be a complication of acute otitis media. Pain is rarely present. All three may be associated with hearing loss. The hearing loss in OME, due to its chronic nature, may affect a child's ability to learn.

Bronchitis type of lower respiratory disease

Bronchitis is inflammation of the bronchi in the lungs. Symptoms include coughing up mucus, wheezing, shortness of breath, and chest discomfort. Bronchitis is divided into two types: acute and chronic. Acute bronchitis is also known as a chest cold.

Sinusitis human disease

Sinusitis, also known as a sinus infection or rhinosinusitis, is inflammation of the mucous membrane that lines the sinuses resulting in symptoms. Common symptoms include thick nasal mucus, a plugged nose, and facial pain. Other signs and symptoms may include fever, headaches, poor sense of smell, sore throat, and cough. The cough is often worse at night. Serious complications are rare. It is defined as acute sinusitis if it lasts less than 4 weeks, and as chronic sinusitis if it lasts for more than 12 weeks.

The peak rate of colonisation by M. catarrhalis appears to occur around 2 years of age, with a striking difference in colonization rates between children and adults (very high to very low).

M. catarrhalis has recently been gaining attention as an emerging human pathogen. It has been identified as an important cause in bronchopulmonary infection, causing infection through pulmonary aspiration in the upper pulmonary tract. [7] Additionally, it causes bacterial pneumonia, especially in adults with a compromised immune system. [8] It has also been known to cause infective exacerbations in adults with chronic lung disease, and it is an important cause in acute sinusitis, maxillary sinusitis, bacteremia, meningitis, conjunctivitis, acute purulent irritation of chronic bronchitis, urethritis, septicemia (although this is rare), septic arthritis (which is also a rare occurrence),and acute laryngitis in adults and acute otitis media in children. [9] [10] M. catarrhalis is an opportunistic pulmonary invader, and causes harm especially in patients who have compromised immune systems or any underlying chronic disease. [7] [9]

M. catarrhalis has also been linked with septic arthritis in conjunction with bacteremia. [9] Although cases of bacteremia caused by M. catarrhalis have been reported before, this was the first instance in which bacteremia caused by M. catarrhalis was also associated with septic arthritis. A microbiological evaluation of the patient (a 41-year-old male) revealed that M. catarrhalis was the cause of the disease rather than Neisseria as was previously believed. This was also the second case of M. catarrhalis causing septic arthritis (although in the first case, no mention of bacteremia was made). [9]

Along with its relation to septic arthritis, bacteremia is also caused by M. catarrhalis infection, which can range in severity from a slight fever to lethal sepsis and an associated respiratory tract infection is usually also identified. [11] Bacteremia infections caused by M. catarrhalis have a 21% mortality rate among patients. However, this may have been due to a lack of knowledge about the bacterium because of its recent recognition as a pathogen. [11]

Infection of high-grade bacteremia was linked with the development of endocarditis. [11] However, the patients without endocarditis has been related to the background of each patient, especially the existence of other illnesses and any possible immune impairments they may have. Also, although bacteremia caused by M. catarrhalis has been infrequently reported, this may be due to a misdiagnosis or oversight because M. catarrhalis was only recently (1990s) identified as an important pathogen. [11] Many chronic diseases in patients with M. catarrhalis bacteremia can be linked to the patients with immune defects or respiratory debility. Likewise, respiratory debility in patients with bacteremic pneumonia caused by M. catarrhalis infection can be linked with increased rates of pharyngeal colonization, enhancement of bacterial adherence to abnormal epithelium, and increased susceptibility of pulmonary parenchyma to infection. [11]

Antibiotic resistance

Antibiotic sensitivity test: This strain shows resistance to ampicillin because it produces the enzyme b-lactamase. This is confirmed by the disc (nitrocefin) labelled b turning red. M. cat BSAC.JPG
Antibiotic sensitivity test: This strain shows resistance to ampicillin because it produces the enzyme β-lactamase. This is confirmed by the disc (nitrocefin) labelled β turning red.

M. catarrhalis can be treated with antibiotics, but it is commonly resistant to penicillin, ampicillin, and amoxicillin. [11]

Current research priorities involve trying to find a suitable vaccine [12] for this genotypically diverse organism, as well as determining factors involved with virulence, e.g. complement resistance. Lipooligosaccharide is considered one possible virulence factor. [12]

Since the recent recognition of M. catarrhalis as an important pathogenic microbe, development of a possible antibiotic has been ongoing. A fraction of M. catarrhalis strains seemed to be resistant to ampicillin, which makes ampicillin and amoxicillin inappropriate choices of antibiotic against it. [7] Although all strains of M. catarrhalis were susceptible to cotrimoxazole, erythromycin, sulfadimidine, and tetracycline, they were also resistant to trimethoprim. [7] M. catarrhalis resistance to beta-lactam antibiotics, such as ampicillin and amoxicillin, is mediated by periplasmic lipoprotein beta-lactamases BRO-1 and BRO-2, which protect the peptidoglycan layer by hydrolyzing the beta-lactam molecules that enter the bacterial cell. [13] The beta-lactamases are produced in the cytoplasm and translocated to the periplasmic space by twin-arginine translocation pathway, which is a protein secretion pathway that transports proteins across a bilipid membrane in a folded state. [14] M. catarrhalis produces and secretes beta-lactamase containing outer-membrane vesicles that can function as an extracellular delivery system of beta-lactam resistance that promotes the survival of otherwise beta-lactam sensitive bacteria in the vicinity of M. catarrhalis. This behavior is beneficial for the other bacteria and can make the antibiotic treatment of polymicrobial infections more difficult. [15] Also, the resistance of M. catarrhalis to other antibiotics may be attributed to beta-lactamase, as well, because the use of these antibiotics has triggered an increase in development of beta-lactamase, which resists antibiotics. [7]

However, a 1994 study has identified a large protein on the surface of M. catarrhalis that may serve as a target for protective antibodies. [8] This UspA (the designated antigen) protein is the first surface-exposed protein on M. catarrhalis that can be a target for biologically active antibodies, and therefore lead to a vaccination. This protein was also present in all of the strains tested. The large size of the exposed protein macromolecule makes it similar to Neisseria gonorrhoeae outer membrane protein macromolecular complex, which implies that UspA may be a single polypeptide chain. [8]

Active immunization, in a study, of M. catarrhalis in the respiratory tract allowed the control of the growth of M. catarrhalis and led to the development of serum antigens. [10] Also, an enhanced ability exists in the test subjects (mice) to clear M. catarrhalis from their lungs. Likewise, passive immunization of M. catarrhalis from the mice respiratory tracts also enhanced the mice's ability to clear the microbes from their lungs, which means that serum antibodies likely play a large role in the immunization and protection of the respiratory tract. [10] Along with outer membrane proteins that are consistent among different strains of M. catarrhalis, a sort of subclass-specific IgG antibody response to certain outer membrane proteins may also exist. Therefore, the outer membrane antigens of M. catarrhalis also provide a possible vaccine source. Also, a bactericidal serum antibody has also been developed in response to the diseases caused by M. catarrhalis. [10]

Treatment

Treatment options include antibiotic therapy or a so-called "watchful waiting" approach. The great majority of clinical isolates of this organism produce beta-lactamases, so are resistant to penicillin. Resistance to trimethoprim, trimethoprim-sulfamethoxazole (TMP-SMX), clindamycin, and tetracycline have been reported. It is susceptible to fluoroquinolones, most second- and third-generation cephalosporins, erythromycin, and amoxicillin-clavulanate.

Vaccine development

Currently, no vaccine is known in the US against M. catarrhalis infection. It is a significant cause of respiratory tract infections against which a vaccine is sought. Several outer membrane proteins are currently under investigation as potential vaccine antigens, including the porin M35.

Biochemistry

During the first reported case of M. catarrhalis causing bacteremia that was associated with septic arthritis, the microbe was cultured, which revealed much about the morphology of its colonies, as well as M. catarrhalis itself. [9] M. catarrhalis is a large, kidney-shaped, Gram-negative diplococcus. It can be cultured on blood and chocolate agar plates after an aerobic incubation at 37 °C for 24 hours. Cultures revealed gray-white hemispheric colonies about 1 mm in diameter. These colonies were fragile and easy to crumble, and appeared to have a waxy surface. [9]

The hockey puck test was applied to these M. catarrhalis colonies, [9] in which a wooden stick is used to try to push the colonies across the plate. The M. catarrhalis colonies scored positively on this test, which means they could be slid across the plate. The colonies did not demonstrate hemolysis, and were not able to ferment glucose, sucrose, maltose, or lactose. They were able to produce DNase. Cultures of the M. catarrhalis tested positive for oxidase and nitrate reduction, which is characteristic of M. catarrhalis. [9] Many laboratories also perform a butyrate esterase test and a beta-lactamase test. Both tests should be positive and can help to rapidly identify it from a culture. [16]

The recognition of M. catarrhalis as a pathogen has led to studies for possible antibodies against it, which have led to a wider understanding of its composition. The outer membrane protein (OMP) profiles of different strains of M. catarrhalis are extremely similar to each other. [8] Analyses of these OMP profiles with monoclonal antibodies (MAbs) revealed that a few proteins with similar molecular masses in the different strains have cross-reactive epitopes. [8] Also, a surface-exposed protein on M. catarrhalis has an unusually high molecular mass. An 80-kDa OMP on M. catarrhalis is immunogenic and common to all nonencapsulated strands of M. catarrhalis, which suggests it may be used as an antigen for immunization. [8]

Protein secretion

M. catarrhalis utilizes the twin-arginine translocation pathway (TAT pathway) for the transport of folded proteins across the inner membrane. [14] The translocase apparatus is a typical Gram-negative TAT translocase consisting of three essential membrane proteins: TatA, TatB and TatC. TatA proteins form a pore through which passenger proteins are transported and TatB and TatC proteins recognize, bind and direct the passenger proteins to the membrane spanning TatA pore. [14] [17]

The M. catarrhalis TAT translocase protein encoding genes tatA, tatB and tatC are located in a single tatABC locus in the bacterial chromosome and are likely to be transcriptionally and translationally linked due to a single-nucleotide overlap between each gene. [14]

Multiple M. catarrhalis proteins have been predicted or tested to contain the highly conserved leader motif for translocation and to be transported by the TAT pathway. Beta-lactamases BRO-1 and BRO-2 have been shown to be transported by the TAT pathway. Other potential passenger proteins include an iron-dependent peroxidase -like protein, a cytochrome c -like protein and a phosphate ABC transporter inner membrane protein- like protein. A functioning TAT pathway is necessary for the optimal growth of M. catarrhalis even in conditions without antibiotics. [14]

Related Research Articles

Gram-negative bacteria group of bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation

Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the gram-staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall sandwiched between an inner cytoplasmic cell membrane and a bacterial outer membrane.

Group A streptococcal infection

A group A streptococcal infection is an infection with group A streptococcus (GAS). Streptococcus pyogenes comprises the vast majority of the Lancefield group A streptococci, and is often used as a synonym for GAS. However, S. dysgalactiae can also be group A. S. pyogenes is a beta-hemolytic species of Gram positive bacteria that is responsible for a wide range of both invasive and noninvasive infections.

Scarlet fever infectious disease

Scarlet fever is a disease which can occur as a result of a group A Streptococcus infection. The signs and symptoms include a sore throat, fever, headaches, swollen lymph nodes, and a characteristic rash. The rash is red and feels like sandpaper and the tongue may be red and bumpy. It most commonly affects children between five and 15 years of age.

<i>Staphylococcus aureus</i> species of bacterium

Staphylococcus aureus is a Gram-positive, round-shaped bacterium that is a member of the Firmicutes, and it is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often positive for catalase and nitrate reduction and is a facultative anaerobe that can grow without the need for oxygen. Although S. aureus usually acts as a commensal of the human microbiota it can also become an opportunistic pathogen, being a common cause of skin infections including abscesses, respiratory infections such as sinusitis, and food poisoning. Pathogenic strains often promote infections by producing virulence factors such as potent protein toxins, and the expression of a cell-surface protein that binds and inactivates antibodies. The emergence of antibiotic-resistant strains of S. aureus such as methicillin-resistant S. aureus (MRSA) is a worldwide problem in clinical medicine. Despite much research and development, no vaccine for S. aureus has been approved.

Lipopolysaccharide chemical compound

Lipopolysaccharides (LPS), also known as lipoglycans and endotoxins, are large molecules consisting of a lipid and a polysaccharide composed of O-antigen, outer core and inner core joined by a covalent bond; they are found in the outer membrane of Gram-negative bacteria.

<i>Human orthopneumovirus</i> hrs virus

Human orthopneumovirus, formerly Human respiratory syncytial virus (HRSV), is a syncytial virus that causes respiratory tract infections. It is a major cause of lower respiratory tract infections and hospital visits during infancy and childhood. A prophylactic medication, palivizumab, can be employed to prevent HRSV in preterm infants, infants with certain congenital heart defects (CHD) or bronchopulmonary dysplasia (BPD), and infants with congenital malformations of the airway. Treatment is limited to supportive care, including oxygen therapy and more advanced breathing support with CPAP or nasal high flow oxygen, as required.

<i>Klebsiella pneumoniae</i> species of bacterium

Klebsiella pneumoniae is a Gram-negative, non-motile, encapsulated, lactose-fermenting, facultative anaerobic, rod-shaped bacterium. It appears as a mucoid lactose fermenter on MacConkey agar.

<i>Haemophilus influenzae</i> species of bacterium

Haemophilus influenzae is a Gram-negative, coccobacillary, facultatively anaerobic pathogenic bacterium belonging to the Pasteurellaceae family. H. influenzae was first described in 1892 by Richard Pfeiffer during an influenza pandemic.

Bacterial pneumonia is a type of pneumonia caused by bacterial infection.

Human parainfluenza viruses

Human parainfluenza viruses (HPIVs) are the viruses that cause human parainfluenza. HPIVs are a paraphyletic group of four distinct single-stranded RNA viruses belonging to the Paramyxoviridae family. These viruses are closely associated with both human and veterinary disease. Virions are approximately 150–250 nm in size and contain negative sense RNA with a genome encompassing about 15,000 nucleotides.

Carbapenem group of β-lactam antibiotics

Carbapenems are a class of highly effective antibiotic agents commonly used for the treatment of severe or high-risk bacterial infections. This class of antibiotics is usually reserved for known or suspected multidrug-resistant (MDR) bacterial infections. Similar to penicillins and cephalosporins, carbapenems are members of the beta lactam class of antibiotics, which kill bacteria by binding to penicillin-binding proteins, thus inhibiting bacterial cell wall synthesis. However, these agents individually exhibit a broader spectrum of activity compared to most cephalosporins and penicillins. Furthermore, carbapenems are typically unaffected by emerging antibiotic resistance, even to other beta-lactams.

Ampicillin/sulbactam is a combination of the common penicillin-derived antibiotic ampicillin and sulbactam, an inhibitor of bacterial beta-lactamase. Two different forms of the drug exist. The first, developed in 1987 and marketed in the United States under the tradename Unasyn, generic only outside the United States, is an intravenous antibiotic. The second, an oral form called sultamicillin, is marketed under the trade name Ampictam outside the United States. And generic only in the United States, ampicillin/sulbactam is used to treat infections caused by bacteria resistant to beta-lactam antibiotics. Sulbactam blocks the enzyme which breaks down ampicillin and thereby allows ampicillin to attack and kill the bacteria.

Capnocytophaga is a genus of Gram-negative bacteria. Normally found in the oropharyngeal tract of mammals, they are involved in the pathogenesis of some animal bite wounds as well as periodontal diseases.

Adenoiditis inflammation of the adenoid tissue

Adenoiditis is the inflammation of the adenoid tissue it's usually caused by an infection. Adenoiditis is treated using medication or surgical intervention.

Klebsiella pneumonia infection by Klebsiella bacteria

Klebsiella pneumonia (KP) is a form of bacterial pneumonia associated with Klebsiella pneumoniae. It is typically due to aspiration and alcoholism may be a risk factor, though it is also commonly implicated in hospital-acquired urinary tract infections, and COPD individuals

Kingella kingae is a species of Gram-negative aerobic coccobacilli. First isolated in 1960 by Elizabeth O. King, it was not recognized as a significant cause of infection in young children until the 1990s, when culture techniques had improved enough for it to be recognized. It is best known as a cause of septic arthritis, osteomyelitis, spondylodiscitis, bacteraemia, and endocarditis, and less frequently lower respiratory tract infections and meningitis.

A pneumococcal infection is an infection caused by the bacterium Streptococcus pneumoniae, which is also called the pneumococcus. S. pneumoniae is a common member of the bacterial flora colonizing the nose and throat of 5–10% of healthy adults and 20–40% of healthy children. However, it is also a cause of significant disease, being a leading cause of pneumonia, bacterial meningitis, and sepsis. The World Health Organization estimate that in 2005 pneumococcal infections were responsible for the death of 1.6 million children worldwide.

Acute exacerbation of chronic obstructive pulmonary disease

Acute exacerbation of COPD is a sudden worsening of COPD symptoms that typically lasts for several days. It may be triggered by an infection with bacteria or viruses or by environmental pollutants. Typically, infections cause 75% or more of the exacerbations; bacteria can roughly be found in 25% of cases, viruses in another 25%, and both viruses and bacteria in another 25%. Airway inflammation is increased during the exacerbation resulting in increased hyperinflation, reduced expiratory air flow and decreased gas exchange.

Pathogenic <i>Escherichia coli</i>

Escherichia coli ( Anglicized to ; commonly abbreviated E. coli) is a gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms (endotherms). Most E. coli strains are harmless, but some serotypes are pathogenic and can cause serious food poisoning in humans, and are occasionally responsible for product recalls. E. coli are also responsible for a majority of cases of urinary tract infections. The harmless strains are part of the normal flora of the gut, and can benefit their hosts by producing vitamin K2, and by preventing the establishment of pathogenic bacteria within the intestine.

References

  1. "Moraxella". List of Prokaryotic names with Standing in Nomenclature . Retrieved 2 May 2018.
  2. Embers ME, Doyle LA, Whitehouse CA, Selby EB, Chappell M, Philipp MT (January 2011). "Characterization of a Moraxella species that causes epistaxis in macaques". Veterinary Microbiology. 147 (3–4): 367–75. doi:10.1016/j.vetmic.2010.06.029. PMC   3971920 . PMID   20667430.
  3. Enright MC, McKenzie H (May 1997). "Moraxella (Branhamella) catarrhalis--clinical and molecular aspects of a rediscovered pathogen". Journal of Medical Microbiology. 46 (5): 360–71. doi:10.1099/00222615-46-5-360. PMID   9152030.
  4. Jakobsson HE, Salvà-Serra F, Thorell K, Gonzales-Siles L, Boulund F, Karlsson R, Sikora P, Engstrand L, Kristiansson E, Moore ER (June 2016). "Draft Genome Sequence of Moraxella catarrhalis Type Strain CCUG 353T". Genome Announcements. 4 (3): e00552–16. doi:10.1128/genomeA.00552-16. PMC   4911475 . PMID   27313296.
  5. Mawas F, Ho MM, Corbel MJ (January 2009). "Current progress with Moraxella catarrhalis antigens as vaccine candidates". Expert Review of Vaccines. 8 (1): 77–90. doi:10.1586/14760584.8.1.77. PMID   19093775.
  6. Yu S, Gu XX (June 2007). "Biological and immunological characteristics of lipooligosaccharide-based conjugate vaccines for serotype C Moraxella catarrhalis". Infection and Immunity. 75 (6): 2974–80. doi:10.1128/IAI.01915-06. PMC   1932890 . PMID   17371852.
  7. 1 2 3 4 5 Winstanley TG, Spencer RC (September 1986). "Moraxella catarrhalis: antibiotic susceptibility with special reference to trimethoprim". The Journal of Antimicrobial Chemotherapy. 18 (3): 425–6. doi:10.1093/jac/18.3.425. PMID   3771428.
  8. 1 2 3 4 5 6 Helminen ME, Maciver I, Latimer JL, Klesney-Tait J, Cope LD, Paris M, McCracken GH, Hansen EJ (October 1994). "A large, antigenically conserved protein on the surface of Moraxella catarrhalis is a target for protective antibodies". The Journal of Infectious Diseases. 170 (4): 867–72. doi:10.1093/infdis/170.4.867. PMID   7523537.
  9. 1 2 3 4 5 6 7 8 Melendez PR, Johnson RH (1991). "Bacteremia and septic arthritis caused by Moraxella catarrhalis". Reviews of Infectious Diseases. 13 (3): 428–9. doi:10.1093/clinids/13.3.428. PMID   1907759.
  10. 1 2 3 4 Maciver I, Unhanand M, McCracken GH, Hansen EJ (August 1993). "Effect of immunization of pulmonary clearance of Moraxella catarrhalis in an animal model". The Journal of Infectious Diseases. 168 (2): 469–72. doi:10.1093/infdis/168.2.469. PMID   8335988.
  11. 1 2 3 4 5 6 Ioannidis JP, Worthington M, Griffiths JK, Snydman DR (August 1995). "Spectrum and significance of bacteremia due to Moraxella catarrhalis". Clinical Infectious Diseases. 21 (2): 390–7. doi:10.1093/clinids/21.2.390. PMID   8562749.
  12. 1 2 Peng D, Hong W, Choudhury BP, Carlson RW, Gu XX (November 2005). "Moraxella catarrhalis bacterium without endotoxin, a potential vaccine candidate". Infection and Immunity. 73 (11): 7569–77. doi:10.1128/IAI.73.11.7569-7577.2005. PMC   1273912 . PMID   16239560.
  13. Bootsma HJ, Aerts PC, Posthuma G, Harmsen T, Verhoef J, van Dijk H, Mooi FR (August 1999). "Moraxella (Branhamella) catarrhalis BRO beta-lactamase: a lipoprotein of gram-positive origin?". Journal of Bacteriology. 181 (16): 5090–3. PMC   94001 . PMID   10438784.
  14. 1 2 3 4 5 Balder R, Shaffer TL, Lafontaine ER (June 2013). "Moraxella catarrhalis uses a twin-arginine translocation system to secrete the β-lactamase BRO-2". BMC Microbiology. 13 (1): 140. doi:10.1186/1471-2180-13-140. PMC   3695778 . PMID   23782650.
  15. Schaar V, Nordström T, Mörgelin M, Riesbeck K (August 2011). "Moraxella catarrhalis outer membrane vesicles carry β-lactamase and promote survival of Streptococcus pneumoniae and Haemophilus influenzae by inactivating amoxicillin". Antimicrobial Agents and Chemotherapy. 55 (8): 3845–53. doi:10.1128/AAC.01772-10. PMC   3147650 . PMID   21576428.
  16. Manual of Clinical Microbiology, 10th edition. James Versalovic, copyright 2012 ASM press.
  17. Palmer T, Berks BC (June 2012). "The twin-arginine translocation (Tat) protein export pathway". Nature Reviews. Microbiology. 10 (7): 483–96. doi:10.1038/nrmicro2814. PMID   22683878.