Journal Article
Silent spreaders: multidrug-resistant and hypermucoviscous Klebsiella from animals threaten one health
Michelle de Souza Moura Gonçalves; Cássia C. da Motta; Dayanne A. De Melo; Thérèsse C. N. Holmström; Miliane M. S. De Souza
Brazilian Journal of Microbiology · Vol. 57, Issue 1 · 2026
Abstract
This study investigated the identification, antimicrobial resistance patterns, and phenotypic and genotypic traits of 30 Klebsiella isolates recovered from diverse animal species and infection sites. MALDI-TOF MS demonstrated higher accuracy in species-level identification than conventional phenotypic approaches, revealing a predominance of Klebsiella pneumoniae (80%), followed by K. variicola , K. aerogenes , and K. oxytoca . Multidrug resistance was detected in 46.6% of isolates, while 43.3% were extended-spectrum β-lactamase (ESBL) producers carrying genes such as blaTEM, blaCTX, and blaSHV. One carbapenemase-producing isolate was confirmed, and carbapenemase-encoding genes (blaOXA-48, blaNDM, blaKPC) were identified in additional strains. Notably, hypermucoviscosity was observed in four isolates, including the first report of a hypermucoviscous K. variicola from a dog. These findings highlight the presence of antimicrobial-resistant Klebsiella isolates in animal sources and support the need for integrated One Health surveillance.