[Clinical characterization of blaIMP positive gram-negative rods isolated cases]

Area of Science:

• Medical Microbiology
• Infectious Diseases
• Antimicrobial Resistance

Background:

• The emergence of metallo-beta-lactamase (MBL) genes, such as blaIMP, is a significant global health concern.
• Gram-negative rods (GNR) carrying MBL genes pose a therapeutic challenge due to their resistance to a broad spectrum of antibiotics.

Purpose of the Study:

• To detect blaIMP-positive GNR strains isolated at Oita Medical University Hospital between 1993 and 1999.
• To investigate the clinical characteristics of patients infected or colonized with these blaIMP-positive GNR strains.

Main Methods:

• Detection of blaIMP gene in GNR isolates.
• Antimicrobial susceptibility testing.
• Analysis of patient clinical data, including demographics, comorbidities, and device usage.
• Genotyping of isolates using pulsed field gel electrophoresis (PFGE).

Main Results:

• Twenty-five blaIMP-positive GNR strains (20 Pseudomonas aeruginosa, 5 Serratia marcescens) were identified, predominantly from urinary samples after 1997.
• Most isolates exhibited multidrug resistance, although some remained susceptible to aztreonam or imipenem.
• In 88% of cases, blaIMP-positive GNR were considered the cause of infection.
• Patients were often elderly (over 65), had malignant diseases, and utilized indwelling catheters (urinary, intratracheal, or intravenous).
• Isolates often originated from the same hospital department and shared similar genotypes.

Conclusions:

• The study highlights the prevalence and clinical significance of blaIMP-positive GNR in a hospital setting.
• Catheterization appears to be a risk factor for infection with these multidrug-resistant organisms.
• The findings underscore the need for surveillance and infection control measures against MBL-producing GNR.