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

Abstract

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.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: blaTEM dominated in most countries, while blaSHV 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.

Keywords: extended-spectrum beta-lactamase genes; feces; multinational; real-time PCR; residents.

Fig 1

Quantitative levels of ESBL genes in resident feces. X in the figure indicates the median level of positive samples.