Background: Multidrug-resistant bacteria present resistance mechanisms against β-lactam antibiotics, such as Extended-Spectrum Beta-lactamases (ESBL) and Metallo-β-lactamases enzymes (MBLs) operon encoded in Gram-negative species. Likewise, Gram-positive bacteria have evolved other mechanisms through mec genes, which encode modified penicillin-binding proteins (PBP2). This study aimed to determine the presence and spread of β-lactam antibiotic resistance genes and the microbiome circulating in Quito’s Public Transport (QTP). Methods: A total of 29 station turnstiles were swabbed to extract the surface environmental DNA. PCRs were performed to detect the presence of 13 antibiotic resistance genes and to identify 16S rDNA barcoding, followed by clone analysis, Sanger sequencing and BLAST search. Results: ESBL genes blaTEM-1 and blaCTX-M-1 and MBL genes blaOXA-181 and mecA were detected along QPT stations. Two subvariants were found for blaTEM-1, blaCTX-M-1, and blaOXA-181. Almost half of the circulating bacteria found at QPT stations were common human microbiota species including those classified by the WHO as pathogens of critical and high-priority surveillance. Conclusions: β-lactam antibiotic resistance genes are widely spread throughout QPT. This is the first report of blaOXA-181 in environmental samples in Ecuador. Moreover, we detected a new putative variant of this gene. Some commensal coagulase-negative bacteria may have a role as mecA resistance reservoirs

The genus Prototheca, unicellular, non-photosynthetic, yeast-like microalgae, is a pathogen of concern for the dairy industry causing bovine mastitis that currently cannot be cured and hence generates significant economic losses in milk production. In this study, for the first time in Ecuador, we identify Prototheca bovis as the etiologic agent of chronic mastitis in dairy cattle. Milk samples (n=458) of cows with chronic mastitis were cultured on Sabouraud Dextrose Agar (SDA). Microscopy and cytB gene sequencing were used to identify Prototheca, whereby Prototheca bovis was isolated from 15.1% (n=69) of the milk samples, one of the highest infection rates that can be found in the literature in a “non-outbreak” situation. No other Prototheca species were found. We were unable to isolate the alga from environmental samples. We showed that P. bovis was relatively resistant to disinfectants used to sterilize milking equipment on the cattle farms where it was isolated. We discuss how to avoid future infection and also hypothesize that the real prevalence of Prototheca infection in bovine mastitis is probably much higher than what was detected. We recommend a protocol to increase the diagnostic yield in the bacteriology laboratory.