Moraxella catarrhalis – Pathogen or Commensal?

Aebi, Christoph

doi:10.1007/978-1-4419-7185-2_9

Cited by 42 publications

(37 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moraxella spp. are Gram-negative bacteria that are commensals or pathogens for animals (cattle, sheep, cats, dogs, rabbits, and pigs), and Moraxella catarrhalis is a mucosal commensal or pathogen for humans (26). In silico analysis of GenBank databases revealed that a gene encoding a putative MCR-like protein was located on the chromosome of the M. catarrhalis genome, sharing 59% and 60% amino acid identity with MCR-1 and MCR-2, respectively.…”

mentioning

confidence: 99%

Moraxella Species as Potential Sources of MCR-Like Polymyxin Resistance Determinants

Kieffer

Nordmann

Poirel

2017

Antimicrob Agents Chemother

View full text Add to dashboard Cite

Plasmid-mediated resistance to polymyxins mediated by the MCR-1/2 determinants has been reported in Enterobacteriaceae worldwide. Using PCR-based and cloning strategies, a series of Moraxella spp. were screened for mcr-like genes. Moraxella spp. that are mainly animal pathogens but may also be human pathogens were identified as potential reservoirs of mcr-like genes.KEYWORDS polymyxin, plasmid, resistance, reservoir, animal, MCR R esistance to polymyxins in Enterobacteriaceae results mostly from chromosomal mutations in genes involved in modification of lipopolysaccharide (LPS) (1, 2). In particular, it has been shown that mutations, truncations, or insertions into genes encoding LPS-modifying enzymes may be responsible for acquired resistance to polymyxins in Enterobacteriaceae (1, 3, 4), Acinetobacter baumannii, and Pseudomonas aeruginosa (1, 5). However, the plasmid-mediated polymyxin resistance determinant MCR-1 was recently found in Escherichia coli and Klebsiella pneumoniae isolates recovered from humans and animals in China (6). The mcr-1 gene has been reported worldwide in other enterobacterial genera, including Enterobacter, Salmonella, and Shigella (7-11). This resistance was identified in Enterobacteriaceae isolated from various animal species, including cattle, chicken, and pigs (12-14), and from river samples and vegetables (15).MCR-1 is a 541-amino-acid phosphoethanolamine transferase that adds phosphoethanolamine to the lipid A moiety of LPS, leading to a more cationic LPS structure and consequently to resistance to polymyxins (6). Recently, the MCR-2 protein (538 amino acids long, 81% amino acid identity with MCR-1) was identified in Belgium from colistin-resistant E. coli (16). Additionally, the MCR-1.2 and MCR-1.3 variants (both exhibiting single amino acid substitutions versus MCR-1) were identified in Italy and China, respectively (17,18). Several plasmid types carrying the mcr-1 gene, belonging to the IncI2, IncHI2, or IncX4 incompatibility groups, have been identified (8,10,12). In addition, the mcr-1.2 and mcr-2 genes were found on IncX4 plasmid scaffolds (16,17).It is often suggested that animals treated with polymyxins represent a significant reservoir of polymyxin-resistant Gram-negative isolates, particularly MCR-producing isolates (19). In fact, polymyxins are heavily used in veterinary medicine, and Europeans, particularly in Spain and Italy, have a high consumption of those antibiotics for food-producing animals (20). The frequent identification of MCR-1-producing isolates from animals further supports the hypothesis that the animal world might be the primary source of this resistance determinant.

show abstract

mentioning

confidence: 99%

Moraxella Species as Potential Sources of MCR-Like Polymyxin Resistance Determinants

Kieffer

Nordmann

Poirel

2017

Antimicrob Agents Chemother

View full text Add to dashboard Cite

show abstract

“…During the past decades, it has gained increasing attention as a mucosal pathogen [1,2,3] with the potential to cause upper and lower respiratory tract infections. In preschool children M. catarrhalis is the third most common cause of infective otitis media [4].…”

Section: Introductionmentioning

confidence: 99%

Collagen VI Is Upregulated in COPD and Serves Both as an Adhesive Target and a Bactericidal Barrier for <b><i>Moraxella catarrhalis</i></b>

Abdillahi

Bober²,

Nordin

et al. 2015

J Innate Immun

View full text Add to dashboard Cite

Moraxella catarrhalis is a Gram-negative human mucosal commensal and pathogen. It is a common cause of exacerbation in chronic obstructive pulmonary disease (COPD). During the process of infection, host colonization correlates with recognition of host molecular patterns. Importantly, in COPD patients with compromised epithelial integrity the underlying extracellular matrix is exposed and provides potential adhesive targets. Collagen VI is a ubiquitous fibrillar component in the airway mucosa and has been attributed both adhesive and killing properties against Gram-positive bacteria. However, less is known regarding Gram-negative microorganisms. Therefore, in the present study, the interaction of M. catarrhalis with collagen VI was characterized. We found that collagen VI is upregulated in the airways of COPD patients and exposed upon epithelial desquamation. Ex vivo, we inoculated airway biopsies and fibroblasts from COPD patients with M. catarrhalis. The bacteria specifically adhered to collagen VI-containing matrix fibrils. In vitro, purified collagen VI microfibrils bound to bacterial surface structures. The primary adhesion target was mapped to the collagen VI α₂-chain. Upon exposure to collagen VI, bacteria were killed by membrane destabilization in physiological conditions. These previously unknown properties of collagen VI provide novel insights into the extracellular matrix innate immunity by quickly entrapping and killing pathogen intruders.

show abstract

“…oraxella catarrhalis is an increasingly important human-specific pathogen contributing to worldwide morbidity and mortality that has transitioned from an emerging to an established pathogen (1)(2)(3). Otitis media in children is the primary cause of new antibiotic prescriptions and pediatric office visits, with M. catarrhalis accounting for 10% to 20% of acute otitis media episodes (2,(4)(5)(6).…”

mentioning

confidence: 99%

Expression of the Oligopeptide Permease Operon of Moraxella catarrhalis Is Regulated by Temperature and Nutrient Availability

Jones

Murphy

2015

Infect Immun

View full text Add to dashboard Cite

Moraxella catarrhalis causes otitis media in children and exacerbations of chronic obstructive pulmonary disease in adults. Together, these two conditions contribute to enormous morbidity and mortality worldwide. The oligopeptide permease (opp) ABC transport system is a nutritional virulence factor important for the utilization of peptides. The substrate binding protein OppA, which binds peptides for uptake, is a potential vaccine antigen, but little was known about the regulation of gene expression. The five opp genes oppB, oppC, oppD, oppF, and oppA are in the same open reading frame. Sequence analysis predicted two promoters, one located upstream of oppB and one within the intergenic region between oppF and oppA. We have characterized the gene cluster as an operon with two functional promoters and show that cold shock at 26°C for <0.5 h and the presence of a peptide substrate increase gene transcript levels. Additionally, the putative promoter upstream of oppA contributes to the transcription of oppA but is not influenced by the same environmental cues as the promoter upstream of oppB. We conclude that temperature and nutrient availability contribute to the regulation of the Opp system, which is an important nutritional virulence factor in M. catarrhalis. Moraxella catarrhalis is an increasingly important human-specific pathogen contributing to worldwide morbidity and mortality that has transitioned from an emerging to an established pathogen (1-3). Otitis media in children is the primary cause of new antibiotic prescriptions and pediatric office visits, with M. catarrhalis accounting for 10% to 20% of acute otitis media episodes (2, 4-6). Chronic obstructive pulmonary disease (COPD) is the third leading cause of death in the United States, with M. catarrhalis contributing to at least 10% of exacerbations (7-11). The socioeconomic burden of otitis media and COPD is significant, with an estimated $50 billion dollars annually in health care expenses globally (5, 9, 12). In view of the morbidity and health care cost associated with M. catarrhalis, it is important to understand the mechanisms of pathogenesis in order to guide development of novel approaches to treatment and prevention (2,13,14). In previous work, we identified OppA as a promising vaccine antigen and a nutritional virulence factor for M. catarrhalis (15,16).We previously characterized the oligopeptide permease (opp) gene cluster as an ABC transport system vital for the utilization of peptide substrates. The gene cluster encodes two permeases, OppB and OppC; two ATPases, OppD and OppF; and a substrate binding protein, OppA (16). We hypothesized that this gene cluster was transcribed as an operon and that environmental factors, temperature and essential nutrients available as peptides, would alter the rate of transcription.The lower respiratory tract has a normal body temperature of 37°C, while the upper airways, specifically the nasopharynx, where M. catarrhalis first colonizes, ranges from 34°C at room temperature (25°C) down to 26°C after a short...

show abstract

Moraxella catarrhalis – Pathogen or Commensal?

Cited by 42 publications

References 44 publications

Moraxella Species as Potential Sources of MCR-Like Polymyxin Resistance Determinants

Moraxella Species as Potential Sources of MCR-Like Polymyxin Resistance Determinants

Collagen VI Is Upregulated in COPD and Serves Both as an Adhesive Target and a Bactericidal Barrier for <b><i>Moraxella catarrhalis</i></b>

Expression of the Oligopeptide Permease Operon of Moraxella catarrhalis Is Regulated by Temperature and Nutrient Availability

Contact Info

Product

Resources

About