Multinational comparison of the detection of extended-spectrum beta-lactamase genes in healthy resident feces

The spread of antimicrobial-resistant bacteria, especially in developing countries, is a critical healthcare issue. Among these, extended-spectrum beta-lactamase (ESBL)-producing bacteria are particularly concerning due to their resistance to third- and fourth-generation cephalosporins. Traditional methods for assessing bacterial resistance involve culturing bacteria on selective media from fecal samples, which may lead to selection bias. Alternatively, real-time PCR allows for detecting resistance genes directly from fecal DNA, providing a broader view of resistant bacteria. In this study, we evaluated the utility of a real-time PCR assay targeting ESBL-producing genes as a comprehensive detection method for ESBL-producing resistant bacteria in fecal samples. Additionally, we conducted a multinational comparative analysis of the colonization status of residents using this approach. The study analyzed ESBL genes in fecal samples from 161 residents in four countries: Ecuador, Ghana, Vietnam, and Japan. Samples from Ecuador, Ghana, and Vietnam, where ESBL carriage was notably high, revealed gene variations by country, with blaTEM genes being most common except in Ghana, where blaSHV genes predominated. These variations suggest that different bacterial hosts carry ESBL genes across countries. Quantitative PCR results further highlight that blaTEM is the most abundant ESBL gene. Although gene presence does not confirm antibiotic resistance, these findings underline significant ESBL carriage in low- and middle-income countries. The study emphasizes that gene detection in fecal samples is valuable for understanding resistant bacteria spread in communities.