Molecular and genetic characterization of carbapenemase-producing bacteria in Venezuela

Area of Science:

• Medical Microbiology
• Infectious Diseases
• Molecular Epidemiology

Background:

• Carbapenem-resistant Gram-negative bacteria (CRGNB) pose a significant global health threat.
• Limited characterization of CRGNB in Venezuela hinders effective infection control strategies.
• Understanding the genetic basis and epidemiology of carbapenem resistance is crucial for public health.

Purpose of the Study:

• To characterize carbapenem-resistant Gram-negative bacteria isolates from a clinical setting in Venezuela.
• To identify the types and prevalence of carbapenemase genes among these isolates.
• To investigate the genetic environment of carbapenemase genes, particularly blaNDM-1.

Main Methods:

• Isolation and identification of Gram-negative bacteria from clinical samples.
• Phenotypic and genotypic characterization of carbapenem resistance.
• Detection of carbapenemase genes (blaKPC, blaVIM, blaOXA, blaNDM) using molecular methods.
• Analysis of the genetic structure surrounding the blaNDM-1 gene.

Main Results:

• 34 CRGNB isolates were characterized, primarily Klebsiella pneumoniae (17), Pseudomonas aeruginosa (9), and Acinetobacter baumannii (8).
• 85% of isolates harbored carbapenemase genes: blaKPC-2 (34.4%), blaVIM-type (24.1%), blaOXA-23 (24.1%), blaNDM-1 (27.5%), and co-existence of blaOXA-23/blaNDM-1 (6.8%).
• The blaNDM-1 gene in Acinetobacter baumannii exhibited an uncommon genetic structure, while in Klebsiella pneumoniae, it showed a common plasmid-associated structure.

Conclusions:

• This study provides the first detailed characterization of carbapenemase-producing bacteria in Venezuela.
• The presence of diverse carbapenemase genes, including blaNDM-1, highlights the urgent need for enhanced surveillance and control measures.
• Understanding the genetic context of resistance genes is vital for predicting and managing the spread of CRGNB.