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Epidemiologic Study of Pseudomonas aeruginosa in critical patients and reservoirs
A L Corona-Nakamura1, M G Miranda-Novales, B Leaños-Miranda
1Departamento de Infectología, Centro Médico del Occidente, Guadalajara, Jalisco, Mexico.
Background:
Pseudomonas aeruginosa is a common cause of nosocomial infections, particularly in intensive care units (ICUs). The aim of this study was to characterize P. aeruginosa clinical isolates by comparing antimicrobial susceptibility patterns with the presence of plasmids and to establish the clonal relatedness by pulsed-field gel electrophoresis (PFGE) typing.
Methods:
The patients included those with isolation of P. aeruginosa hospitalized for more than 48 h in the ICU from April to May 1998. Environmental and staff cultures were obtained simultaneously. Minimal inhibitory concentrations, plasmid DNA profiles, and PFGE genomic patterns of enzyme restriction chromosomal DNA were compared.
Results:
Sixty P. aeruginosa isolates were obtained from 197 clinical specimens, 178 environmental samples, and 47 hand cultures of personnel. Antimicrobial resistance was as follows: tobramycin 100%; ticarcillin, cefotaxime, ceftriaxone, ceftazidime, and gentamicin 80%; cefepime 60%; amikacin, ticarcillin/clavulanate, imipenem, and meropenem 40%; piperacillin and norfloxacin 20%; carbenicillin 12%, and ciprofloxacin 0%. Plasmids were detected in 11 isolates (18%). PFGE typing showed that 23 isolates belonged to a common clone (pattern A), identified from five patients, two nurses, and 10 environmental samples. Ten isolates were grouped in four clusters and 27 isolates had unrelated genomic patterns. There was no relationship among DNA genomic patterns, plasmid profiles, and susceptibility patterns.
Conclusions:
PFGE demonstrated the existence of a common clone in a critical care area. Reinforcement of infection control measures is needed to avoid horizontal transmission and severe infections.
Insights
A common clone of Pseudomonas aeruginosa was identified in an intensive care unit (ICU), highlighting the need for enhanced infection control to prevent the spread of this nosocomial pathogen.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Hospital Epidemiology
Background:
- Pseudomonas aeruginosa is a significant cause of hospital-acquired infections, particularly in intensive care units (ICUs).
- Characterizing clinical isolates is crucial for understanding transmission dynamics and implementing effective control measures.
Purpose of the Study:
- To compare antimicrobial susceptibility patterns with plasmid presence in P. aeruginosa clinical isolates.
- To determine clonal relatedness using pulsed-field gel electrophoresis (PFGE) typing.
Main Methods:
- Analysis of P. aeruginosa isolates from clinical specimens, environmental samples, and staff cultures.
- Comparison of antimicrobial susceptibility, plasmid DNA profiles, and PFGE genomic patterns.
- Patients hospitalized >48 hours in the ICU were included.
Main Results:
- A common P. aeruginosa clone (pattern A) was identified across patients, staff, and the environment.
- High antimicrobial resistance rates were observed for several antibiotics, with 100% resistance to tobramycin.
- No correlation was found between genomic patterns, plasmid profiles, and antimicrobial susceptibility.
Conclusions:
- Pulsed-field gel electrophoresis (PFGE) confirmed a prevalent clone within the critical care setting.
- Strengthened infection control protocols are essential to mitigate horizontal transmission and severe P. aeruginosa infections.