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At least 379 records · Page 21Linked to original sources
PubMed2001

Epidemiology of chronic Pseudomonas aeruginosa infections in cystic fibrosis.

Chronic lung infection with Pseudomonas aeruginosa is primarily responsible for pulmonary deterioration of cystic fibrosis patients. The purpose of this study was to type the P. aeruginosa isolates collected sequentially from cystic fibrosis patients, chronically colonized with P. aeruginosa, by random amplified polymorphic DNA fingerprinting-PCR (RAPD-PCR). Sequential P. aeruginosa isolates (n: 130) that had been collected from 20 CF patients over at least 9 years were investigated. The isolates were analyzed by RAPD-PCR using two arbitrary primers. Antimicrobial susceptibility testing of all isolates was performed by the disc diffusion method. RAPD-PCR typing demonstrated that strains dissimilar in colony morphotype and of different antibiotic susceptibility patterns could be of the same genotype. Some CF patients were colonized with a rather constant P. aeruginosa flora, with strains of different phenotypes but of one genotype. However, some patients may be colonized with more than one genotype. The results also demonstrated that there might be a risk of cross-colonization between CF patients followed-up at the same center.

Adolescent↗
PubMed1992

Seasonal onset of initial colonisation and chronic infection with Pseudomonas aeruginosa in patients with cystic fibrosis in Denmark.

BACKGROUND AND METHODS: To assess the relation between seasonal variation and the onset of initial and chronic Pseudomonas aeruginosa infection, 300 Danish patients with cystic fibrosis were investigated. A retrospective analysis based on case reports was performed to identify the date and year of initial and chronic P aeruginosa infection from 1965 to 1990. RESULTS: Sixty six per cent of the patients contracted their initial P aeruginosa colonisation and 68% contracted chronic infection during the winter months (October to March). Despite major changes in treatment, including improved and intensified antibiotic treatment, during the investigation period in our cystic fibrosis centre, the seasonal difference in P aeruginosa infection persisted. CONCLUSIONS: As respiratory virus infections have the same seasonal distribution in Denmark such infections may pave the way for P aeruginosa and thus explain the parallel seasonal occurrence of this pathogen in patients with cystic fibrosis.

Chronic Disease↗
PubMed1997

Pseudomonas aeruginosa infection in embryonated hen's eggs. An alternative in vivo model for the screening of antibacterial substances.

Embryonated hens' eggs can be reliably infected by Pseudomonas aeruginosa in laboratory experiments. Therapy tests with the antibiotics azlocillin (CAS 37091-66-0) and gentamicin (CAS 13291-74-2) on this type of infected hens' eggs demonstrate that this test system offers a realistic alternative to septic experiments with small laboratory rodents. Chick embryos survive a lethal Pseudomonas infection when azlocillin or gentamicin in a relevant therapeutic dose are administered immediately after the infective agent. The use of Pseudomonas infected chick embryos in the screening for new antiinfectives allows, therefore, a considerable reduction of the number of laboratory rodents required.

Animal Testing Alternatives↗
PubMed2005

Hypermutation is a key factor in development of multiple-antimicrobial resistance in Pseudomonas aeruginosa strains causing chronic lung infections.

Pseudomonas aeruginosa is the most relevant pathogen producing chronic lung infections in patients with chronic underlying diseases such as cystic fibrosis (CF), bronchiectasis, and chronic obstructive pulmonary disease (COPD). Hypermutable (or mutator) P. aeruginosa strains, characterized by increased (up to 1,000-fold) spontaneous mutation rates due to alterations of the DNA mismatch repair (MMR) system have been found at high frequencies in the lungs of CF patients, but their role in other chronic processes is still unknown. Sixty-two P. aeruginosa isolates from 30 patients with underlying non-CF chronic respiratory diseases (22 with bronchiectasis and 8 with COPD) and documented chronic infection were studied. Antibiotic susceptibility profiles and mutation frequencies were determined, and complementation assays using the cloned wild-type mutS gene and molecular epidemiology studies (pulsed-field electrophoresis, [PFGE]) were performed with these strains. Thirty-three (53%) of the isolates were hypermutable, and 17 (57%) of the 30 patients were colonized by hypermutable strains. Strains from 11 of the 17 patients were found to be defective in the MMR mutS gene by complementation assays. Interpatient transmission of strains was ruled out by PFGE. Multiple-antimicrobial resistance was documented in 42% of the hypermutable strains in contrast to 0% resistance in the nonhypermutable strains (P < 0.0001). Hypermutable P. aeruginosa strains are extremely prevalent in chronic infections in contrast to what has been described in acute processes, suggesting a role of hypermutation in bacterial adaptation for long-term persistence. Furthermore, hypermutation is found to be a key factor for the development of multiple-antimicrobial resistance, and therefore these findings are expected to have important consequences for the treatment of chronic infections.

Adenosine Triphosphatases↗
PubMed1989

Oral ciprofloxacin and a monoclonal antibody to lipopolysaccharide protect leukopenic rats from lethal infection with Pseudomonas aeruginosa.

To study the treatment of infection with Pseudomonas aeruginosa, a leukopenic rat model was developed that closely mimics the pathogenesis of Pseudomonas infection in man. This model achieved approximately 90% mortality within 10 d of infection. Pseudomonas organisms were inconsistently shed from the feces despite gastrointestinal colonization (9 fecal v. 23 cecal cultures positive for challenge strain in 28 rats). Treatment of rats with oral ciprofloxacin at 40 mg/kg afforded complete protection. A suboptimal dose of ciprofloxacin (20 mg/kg), achieving peak levels of 0.31 micrograms/mL in serum and 26.3 micrograms/mL in stool, resulted in survival of 8 (40%) of 20 rats. Intraperitoneal administration of a monoclonal antibody directed at the lipopolysaccharide of the challenge strain of Pseudomonas resulted in survival of 5 rats (26%). The combination of the two increased the survival to 75% (15 of 20, P less than 0.05 compared to either treatment alone). Thus, the combination of suboptimal doses of ciprofloxacin and a monoclonal antibody appears to protect leukopenic rats from lethal infection better than either treatment alone.

Administration, Oral↗
PubMedDate not supplied

[Pseudomonas aeruginosa as the pathogen in opportunistic infections].

Pseudomonas aeruginosa, in spite of being an ubiquitous microorganism, rarely colonizes healthy individuals. Hospitalization, as well as the length of time spent in hospital, significantly increase the rate of colonization, especially in immunocompromized patients. Antibacterial chemotherapy or prophylaxis together with invasive diagnostic procedures favour colonization and infection with P. aeruginosa. Immune deficiencies and adverse interactions of P. aeruginosa with the immune system facilitate infection. Thus, a number of exogenous as well as endogenous factors and their interactions favour infection of patients with P. aeruginosa.

Drug Resistance, Microbial↗
PubMed2003

Highly adherent small-colony variants of Pseudomonas aeruginosa in cystic fibrosis lung infection.

Pseudomonas aeruginosa, an opportunistic human pathogen and ubiquitous environmental bacterium, is capable of forming specialized bacterial communities, referred to as biofilm. The results of this study demonstrate that the unique environment of the cystic fibrosis (CF) lung seems to select for a subgroup of autoaggregative and hyperpiliated P. aeruginosa small-colony variants (SCVs). These morphotypes showed increased fitness under stationary growth conditions in comparison with clonal wild-types and fast-growing revertants isolated from the SCV population in vitro. In accordance with the SCVs being hyperpiliated, they exhibited increased twitching motility and capacity for biofilm formation. In addition, the SCVs attached strongly to the pneumocytic cell line A549. The emergence of these highly adherent SCVs within the CF lung might play a key role in the pathogenesis of P. aeruginosa lung infection, where a biofilm mode of growth is thought to be responsible for persistent infection.

Bacterial Adhesion↗
PubMed1994

PA-I and PA-II lectin interactions with the ABO(H) and P blood group glycosphingolipid antigens may contribute to the broad spectrum adherence of Pseudomonas aeruginosa to human tissues in secondary infections.

Pseudomonas aeruginosa may cause serious infections in most human tissues/organs. Its adherence to them is mediated by a battery of adhesins including the PA-I and PA-II lectins, which are produced in this bacterium in high quantities. PA-I binds to the D-galactose of the erythrocyte glycosphingolipids exhibiting highest affinities for B and Pk (followed by P1) antigens, while PA-II preferentially binds to the L-fucose of H, A and B antigens. Intact P. aeruginosa cells also exhibit a clear Pk and P1 over p preference. Such affinities for the most common human ABH and P system antigens may underlie the widespread tissue infectivity and pathogenicity of this bacterium.

ABO Blood-Group System↗