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 <i>bla</i>TEM genes being most common except in Ghana, where <i>bla</i>SHV genes predominated. These variations suggest that different bacterial hosts carry ESBL genes across countries. Quantitative PCR results further highlight that <i>bla</i>TEM 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.IMPORTANCEThe rise of antimicrobial-resistant bacteria, particularly extended-spectrum beta-lactamase (ESBL)-producing strains, poses a serious threat to healthcare in developing countries. This study utilized real-time PCR to detect ESBL genes directly from fecal DNA of 161 participants across four countries, offering a comprehensive analysis without the biases of traditional culture-based methods. High ESBL gene carriage rates were found in Ecuador, Ghana, and Vietnam, with regional differences in gene prevalence: <i>bla</i>TEM dominated in most countries, while <i>bla</i>SHV was most frequent in Ghana. These results highlight the widespread community-level dissemination of ESBL genes in low- and middle-income countries, underscoring the importance of using gene detection as a tool for assessing the spread of resistant bacteria.