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1.
J Infect Dis ; 174(3): 636-8, 1996 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8769627

RESUMO

The complement phenotypes of Moraxella catarrhalis isolates obtained from adult patients with acute laryngitis were investigated using a microliter serum bactericidal assay and compared with those of other donor groups. Laryngitis isolates had a higher proportion (57%) of complement-resistant strains than did carrier strains from healthy 8- to 13-year-old schoolchildren (16%). The difference between these groups was statistically significant (chi2 [3 x 2 table] = 21.55; P < .001). The relatively frequent occurrence of the complement-resistant (virulence-associated) phenotype in adults with acute laryngitis supports the theory of an active role of M. catarrhalis in the pathogenesis of acute laryngitis.


Assuntos
Proteínas do Sistema Complemento/química , Laringite/microbiologia , Moraxella catarrhalis/patogenicidade , Virulência/genética , Adolescente , Adulto , Criança , Pré-Escolar , Proteínas do Sistema Complemento/genética , Proteínas do Sistema Complemento/fisiologia , Humanos , Moraxella catarrhalis/isolamento & purificação , Fenótipo
2.
FEMS Immunol Med Microbiol ; 11(3): 207-11, 1995 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-7581272

RESUMO

The purpose of this study was to investigate complement resistance in Branhamella (Moraxella) catarrhalis isolated from healthy schoolchildren or sputum-producing adult patients. Two techniques were used: a serum bactericidal assay as the gold standard and an easier 'culture and spot' test. Children (age 4-13; n = 303) and patients (n = 1047) showed high colonization/infection rates with B. catarrhalis (31% and 19%, respectively). Complement resistance or intermediate sensitivity occurred frequently in patient isolates (62% and 27%, respectively) and less often in children (33% and 8.5%, respectively; P << 0.0001). In young children (age 4-5 years), the proportion of complement-resistant strains was around 50%. Complement resistance in B. catarrhalis is associated with illness and may hence be considered a virulence factor.


Assuntos
Proteínas do Sistema Complemento/metabolismo , Moraxella catarrhalis/imunologia , Moraxella catarrhalis/patogenicidade , Adolescente , Adulto , Atividade Bactericida do Sangue , Portador Sadio/microbiologia , Criança , Pré-Escolar , Humanos , Moraxella catarrhalis/isolamento & purificação , Infecções por Neisseriaceae/microbiologia , Nariz/microbiologia , Faringe/microbiologia , Escarro/microbiologia , Virulência/imunologia
3.
J Infect Dis ; 170(6): 1613-6, 1994 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-7996007

RESUMO

Resistance of microorganisms to antimicrobial agents is an increasing problem in the treatment of infectious diseases. In mixed infections, an interesting development can arise when one organism protects another from being killed by an antibiotic. Unfortunately, in the case of respiratory tract infections, experimental evidence of this development is poor. In this study, mice intranasally infected with a lethal number of pneumococci and treated with a curative dose of penicillin or amoxicillin died from pneumococcal pneumonia when they were coinoculated with beta-lactamase-producing Moraxella catarrhalis. beta-lactamase-negative M. catarrhalis did not show a similar indirect pathogenic effect. Treatment with a combination of amoxicillin and the beta-lactamase inhibitor clavulanic acid was not affected by beta-lactamase-producing M. catarrhalis. These findings help explain antibiotic failure in respiratory tract infections, even though the causative microorganism is sensitive to the antibiotic in vitro.


Assuntos
Moraxella catarrhalis/enzimologia , Infecções por Neisseriaceae/microbiologia , Penicilinas/uso terapêutico , Pneumonia Pneumocócica/tratamento farmacológico , beta-Lactamases/metabolismo , Amoxicilina/uso terapêutico , Combinação Amoxicilina e Clavulanato de Potássio , Animais , Ácidos Clavulânicos/uso terapêutico , Quimioterapia Combinada/uso terapêutico , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Infecções por Neisseriaceae/complicações , Especificidade de Órgãos , Resistência às Penicilinas , Pneumonia Pneumocócica/complicações , Pneumonia Pneumocócica/microbiologia , Streptococcus pneumoniae/efeitos dos fármacos
4.
FEMS Immunol Med Microbiol ; 8(1): 69-75, 1994 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8156053

RESUMO

The efficacy, as oral vaccines, of hepta- and mono-valent, Klebsiella-containing bacterial lysates and a number of control preparations was tested in mice. The preparations were administered during two periods of four days each, interrupted by an interval of 3 days. Fourteen days after the first dose, the animals were challenged either intraperitoneally (i.p.; peritonitis/sepsis model) or intranasally (i.n.; pneumonia model). Animals treated with low doses of Klebsiella lysate, in the form of either a 7-valent lysate or a Klebsiella monolysate, showed enhanced survival in both the peritonitis/sepsis and the pneumonia models. Hexa- and tetra-valent preparations without Klebsiella were not protective in the models tested. Furthermore, it was found that the protection is accompanied by priming for Klebsiella-specific IgG responsiveness (probably at the T cell level) and by significant IgA anti-Klebsiella serum antibody levels in about one third of the animals. The oral efficacy of Klebsiella-containing lysates suggests the presence of an adjacent component that directs Klebsiella antigen(s) to follow a selective intestinal pathway which renders them immunogenic. The identity of this component is under investigation.


Assuntos
Vacinas Bacterianas/imunologia , Infecções por Klebsiella/prevenção & controle , Klebsiella pneumoniae/imunologia , Peritonite/prevenção & controle , Pneumonia/prevenção & controle , Sepse/prevenção & controle , Vacinação/métodos , Administração Oral , Animais , Anticorpos Antibacterianos/sangue , Antígenos de Bactérias/administração & dosagem , Antígenos de Bactérias/imunologia , Antígenos de Bactérias/isolamento & purificação , Vacinas Bacterianas/administração & dosagem , Imunoglobulina A/sangue , Imunoglobulina A/imunologia , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Klebsiella pneumoniae/isolamento & purificação , Masculino , Camundongos
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