Comparison of Moraxella catarrhalis isolates from children and adults for growth on modified New York City medium and potential virulence factors.
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Initial studies found that Moraxella catarrhalis isolates from adults that grew on modified New York City medium (MNYC(+)) that contained antibiotics selective for pathogenic neisseriae differed from strains that did not grow on this medium (MNYC(-)) in their potential virulence properties. It was predicted that higher usage of antibiotics to treat respiratory illness in children might result in higher proportions of MNYC(+) isolates if antibiotics were an important selective pressure for this phenotype. Two of 100 adult isolates (2 %) were MNYC(+), compared to 88 of 88 isolates (100 %) from children (P = 0.000). MNYC(+) strains were serum-resistant and bound in higher numbers to HEp-2 cells that were infected with respiratory syncytial virus (RSV). Endotoxin from an MNYC(+) isolate induced significantly higher pro-inflammatory response levels than endotoxin from an MNYC(-) strain. MNYC(-) adult isolates expressed haemagglutinins and bound in lower numbers to RSV-infected cells, but serum resistance was variable. All isolates from children were MNYC(+), serum-resistant and bound in greater numbers to RSV-infected cells. These results indicate that both RSV infection and antibiotic usage select for the MNYC(+) phenotype. (+info)
Presumed endocarditis caused by BRO beta-lactamase-producing Moraxella lacunata in an infant with Fallot's tetrad.
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A case of presumed endocarditis caused by Moraxella lacunata in a 15-month-old male infant with Fallot's tetrad is described. This infection may have occurred as the result of transmission of this organism between the father and his son. This is the first report of BRO beta-lactamase-producing M. lacunata causing presumed endocarditis. (+info)
Antigenic relationships of Moraxella bovis isolates recovered from outbreaks of infectious bovine keratoconjunctivitis in Argentina, Brazil, and Uruguay between 1983 and 2000.
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Cross-reactivity indices (CRIs) of 28 isolates of Moraxella bovis recovered from outbreaks of infectious bovine keratoconjunctivitis in Argentina (A, 11 isolates), Brazil (B, 7), and Uruguay (U, 10) between 1983 and 2000 were estimated. Hyperimmune sera were produced in rabbits and antibody titres determined with each isolate. Isolates showing CRIs3 70 were placed in the same group. Group I had 13 isolates (A, 1; B, 6; U, 6); group II had 6 isolates (A, 4; U, 2); groups III, IV, and V had 2 isolates each, recovered in Argentina; group VI had 2 isolates, from Uruguay; and group VII had 1 isolate, from Brazil. The CRIs3 70 between vaccine strains and isolates recovered before and after 1990 were 58% and 42%, 50% and 50%, and 33% and 67% with vaccine strains 2419, 2358, and 2439, respectively. Isolate 273, from Uruguay, showed CRIs > 70 with 78% of the isolates and is recommended as the vaccine strain. (+info)
Moraxella osloensis blood and catheter infections during anticancer chemotherapy: clinical and microbiologic studies of 10 cases.
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Moraxella osloensis, a gram-negative bacterium that is saprophytic on skin and mucosa, rarely causes infections. Moreover, infections in patients with cancer have not been reported. We describe 10 cases of M. osloensis blood or catheter infections that occurred during anticancer chemotherapy with or without preexisting neutropenia. The organism was identified definitively by sequencing analysis of the 16S ribosomal RNA gene. Fever (up to 39.7 degrees C) with substantial neutrophilia characterized these infections. The infections were monomicrobic for 3 patients and polymicrobic for 7 patients. Nine patients acquired the infection through central venous catheter colonization. The likely sources of the organism were sinusitis (3 cases), bronchitis (1 case), presumed subclinical mucositis from anticancer therapy (4 cases), and cutaneous graft-vs-host disease (2 cases). The infections resolved, without catheter removal, after antibiotic therapy with cell wall-active agents, to which all strains were shown to be susceptible. The M. osloensis strains exhibited significant morphologic variations on gram stain, and sheep blood agar was the preferred culture medium for 9 strains. (+info)
Immunization with the truncated adhesin moraxella catarrhalis immunoglobulin D-binding protein (MID764-913) is protective against M. catarrhalis in a mouse model of pulmonary clearance.
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Most Moraxella catarrhalis isolates express the outer membrane protein MID. In addition to its specific affinity for immunoglobulin D, MID functions as an adhesin and binds to human epithelium. The adhesive part is localized within MID(764-913). Two mid-deficient M. catarrhalis isolates were constructed and examined in a mouse model of pulmonary clearance. M. catarrhalis devoid of MID was cleared more efficiently, compared with the wild-type counterparts. Furthermore, mice immunized with MID(764-913) cleared M. catarrhalis much more efficiently, compared with mice immunized with bovine serum albumin. MID(764-913) is suggested as a promising candidate in a future M. catarrhalis vaccine. (+info)
Mucoid nitrate-negative Moraxella nonliquefaciens from three patients with chronic lung disease.
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Mucoid strains of Moraxella nonliquefaciens were recovered from the sputa of three indigenous Australians with chronic lung disease. These atypical strains failed to reduce nitrate, and one strain produced beta-lactamase. While the mucoid phenotype of M. nonliquefaciens has rarely been reported, the mucoid nitrate-negative biovar has never been previously reported. (+info)
Detection rates of bacteria in chronic otitis media with effusion in children.
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This study was performed to investigate polymerase chain reaction-based detection of bacterial DNA in middle ear fluid and assess the correlation between the PCR-positive rate with several factors associated with middle ear effusion. The purpose was to gain a further understanding of bacterial infection as a major cause of otitis media with effusion. Of the 278 specimens of middle ear fluid, 39 (14%) tested positive by ordinary culture. The overall detection rate of bacterial DNA using the PCR method was 36.7% for middle ear effusion, and bacterial DNA detection rates of Hemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis in the middle ear effusion were 29.1%, 4.7% and 10.8%, respectively. The bacterial DNA detection rate was higher in ears with a history of acute otitis media than those without the history. High detection rates were observed in patients younger than 48 months who have had a higher tendency to present with acute otitis media. We concluded that PCR is a more sensitive method for the detection of bacteria in middle ear effusion than ordinary culture, and acute otitis media is a major contributor to the pathogenesis of otitis media with effusion. (+info)
Moraxella catarrhalis coaggregates with Streptococcus pyogenes and modulates interactions of S. pyogenes with human epithelial cells.
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The pathogens Streptococcus pyogenes and Moraxella catarrhalis colonize overlapping regions of the human nasopharynx. We have found that M. catarrhalis can dramatically increase S. pyogenes adherence to human epithelial cells and that species-specific coaggregation of these bacteria correlates with this enhanced adherence. (+info)