Bacterıal pathogens ın ventılator-assocıated pneumonıa; molecular assessment of resıstance profıles

Area of Science:

• Medical Microbiology
• Infectious Diseases
• Clinical Research

Background:

• Ventilator-associated pneumonia (VAP) is a leading cause of intensive care unit infections, associated with increased mortality and healthcare costs.
• Multidrug-resistant (MDR) Gram-negative bacteria, including Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa, are the primary VAP pathogens.
• Understanding the molecular resistance mechanisms of these pathogens is crucial for effective treatment and control.

Purpose of the Study:

• To investigate the molecular antibiotic resistance profiles of bacterial isolates from hospital-acquired VAP cases.
• To identify specific resistance genes and characterize the genetic relatedness of VAP pathogens.
• To provide a comprehensive molecular characterization of VAP pathogens in a Turkish hospital setting.

Main Methods:

• Bacterial isolates from VAP cases were collected over one year at Kırşehir Training and Research Hospital.
• Polymerase Chain Reaction (PCR) was used to identify antibiotic resistance genes.
• Repetitive Extragenic Palindromic-PCR (rep-PCR) and Multi-Locus Sequence Typing (MLST) were employed for genotyping and assessing clonal relatedness.

Main Results:

• Acinetobacter baumannii (46.2%) and Klebsiella pneumoniae (42.3%) were the most frequent isolates.
• High resistance rates were observed: A. baumannii showed 100% resistance to ciprofloxacin and carbapenems; K. pneumoniae exhibited 94.73% resistance to carbapenems and 100% to colistin.
• Specific resistance genes (e.g., bla_TEM, bla_OXA-23, bla_NDM-1) were identified, and predominant MLST types (e.g., A. baumannii ST2, K. pneumoniae ST2096) were determined, including novel clones in Türkiye.

Conclusions:

• The study highlights a significant burden of MDR Gram-negative bacteria causing VAP, with concerning resistance to critical antibiotics like carbapenems and colistin.
• Molecular characterization revealed specific resistance genes and prevalent bacterial clones, including novel ones in Türkiye.
• Findings emphasize the urgent need for enhanced infection control measures, judicious antibiotic use, and continuous surveillance of antimicrobial resistance mechanisms in VAP.