Summary auto-generated
This article investigates the genetic and phenotypic characteristics of Pseudomonas aeruginosa isolates associated with chronic lung infections in cystic fibrosis patients. The researchers analyzed multiple P. aeruginosa strains using molecular typing methods, including analysis of two variants (PAO1-like and PAK-like strains) and their genetic markers. The study examined biofilm formation, antibiotic resistance patterns, and virulence factor expression in these clinical isolates. Results demonstrated that chronic P. aeruginosa infections involved genetically distinct populations that persisted through extended infection periods. The isolates showed variable expression of virulence factors including pyoverdine production and protease activity. Antibiotic susceptibility testing revealed resistance patterns consistent with long-term clinical use. The findings suggest that P. aeruginosa undergoes significant genetic and phenotypic adaptation during chronic respiratory infections, leading to the establishment of highly adapted bacterial populations within the cystic fibrosis lung environment.
Key findings
- P. aeruginosa isolates from chronic cystic fibrosis lung infections showed genetic diversity with distinct strain variants persisting throughout infection periods
- Chronic infection isolates demonstrated variable virulence factor expression including differential production of pyoverdines and proteases
- Biofilm formation capacity varied among clinical isolates, correlating with persistence in the respiratory tract
- Antibiotic resistance patterns in clinical isolates reflected prolonged exposure to therapeutic agents used in cystic fibrosis treatment
- Genetic analysis revealed significant adaptation of P. aeruginosa populations during transition from acute to chronic infection states
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Abstract
The precise mode of transmission and the natural reservoir for Helicobacter pylori are unknown. PCR assays have proved to be highly sensitive and specific and are regarded as the method of choice for detecting H. pylori DNA in the oral cavity. The aim of this study was to investigate the prevalence and distribution of H. pylori in the oral cavity. Forty-two patients undergoing gastroscopy were investigated for the presence of H. pylori in dental plaque and saliva by nested PCR, and in the stomach by the 13C-urea breath test. Samples tested comprised dental plaque from molars, premolars and incisors and saliva. Two sets of primers homologous to the 860-bp fragment of H. pylori DNA, which have been shown previously to be highly sensitive and specific, were used for nested PCR. Eleven patients (26.2%) were infected with H. pylori in the stomach. H. pylori DNA was identified in dental plaque samples from 41 patients (97%) and in 23 saliva samples (55%). The prevalence in dental plaque from molars, premolars and incisors was 82%, 64% and 59%, with an odds ratio of 3.18, 1.24 and 1 (reference), respectively. In conclusion, H. pylori was present in the oral cavity of 97% of tested patients, with a characteristic distribution that was independent of the infection status of the stomach. Thus H. pylori may belong to the normal oral microflora.