[Incidence of alginate-coding gene in carbapenem-resistant Pseudomonas aeruginosa strains]
Tomasz Bogiel1, Joanna Kwiecińska-Piróg, Sylwia Kozuszko
1Katedra i Zakład Mikrobiologii, Collegium Medicum im. L. Rydygiera w Bydgoszczy, Uniwersytet Mikołaja Kopernika w Toruniu.
Abstract:
Pseudomonas aeruginosa rods are one of the most common isolated opportunistic nosocomial pathogens. Strains usually are capable to secret a capsule-like polysaccharide called alginate important for evasion of host defenses, especially during chronic pulmonary disease of patients with cystic fibrosis. Most genes for alginate biosynthesis and lysis are encoded by the operon. The aim of our study was to evaluate the incidence of algD sequence, generally use for alginate-coding gene detection, in 120 P. aeruginosa strains resistant to carbapenems. All isolates were obtained in the Department of Clinical Microbiology University Hospital no. 1 of dr A. Jurasz Collegium Medicum of L. Rydygier in Bydgoszcz Nicolaus Copernicus University in Toruń. Examined strains demonstrated resistance to carbenicillin (90,0%), ticarcillin (89,2%) and ticarcillin clavulanate (86,7%). All strains were susceptible to colistin. The majority of examined strains was susceptible to ceftazidime and cefepime (40,8% each) and norfloxacin (37,5%). Presence of algD gene - noted in 112 (93,3%) strains proves that not every strain is capable to produce alginate. It was also found out that differences in algD genes incidence in case of different clinical material that strains were isolated from were not statistically important.
Insights
The algD gene, crucial for alginate production in Pseudomonas aeruginosa, was found in 93.3% of carbapenem-resistant strains. This indicates that not all these opportunistic pathogens can produce alginate, impacting cystic fibrosis lung infections.
Area of Science:
- Clinical Microbiology
- Bacterial Pathogenesis
- Molecular Biology
Background:
- Pseudomonas aeruginosa is a common opportunistic nosocomial pathogen.
- Alginate production is key for P. aeruginosa to evade host defenses, particularly in cystic fibrosis patients.
- The algD gene is essential for alginate biosynthesis.
Purpose of the Study:
- To determine the incidence of the algD gene in carbapenem-resistant P. aeruginosa strains.
- To assess the potential for alginate production in these resistant strains.
Main Methods:
- Analysis of 120 P. aeruginosa isolates resistant to carbapenems.
- Detection of the algD gene using molecular methods.
- Antimicrobial susceptibility testing against various antibiotics.
Main Results:
- The algD gene was detected in 112 (93.3%) of the P. aeruginosa strains.
- The majority of strains exhibited resistance to carbenicillin, ticarcillin, and ticarcillin-clavulanate.
- No statistically significant difference in algD gene incidence was observed based on the source of clinical material.
Conclusions:
- While most carbapenem-resistant P. aeruginosa strains possess the algD gene, its presence does not guarantee alginate production.
- Understanding alginate production capacity is vital for managing P. aeruginosa infections, especially in cystic fibrosis.
- Further research is needed to elucidate the factors controlling alginate expression in P. aeruginosa.
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