Description and comparative genomic analysis of a mcr-1-carrying Escherichia coli ST683/CC155 recovered from touristic coastal water in Northeastern Brazil

Whole genome analysis of multidrug-resistant Escherichia coli isolate collected from drinking water in Armenia revealed the plasmid-borne mcr-1.1-mediated colistin resistance

The rate of polymyxin-resistant Enterobacteriaceae, as well as human and animal infections caused by them, is increasing worldwide, posing a high epidemiological threat since colistin represents a last-resort antibiotic to treat complicated infections. The study of environmental niches, in particular, aquatic ecosystems in terms of genome analysis of inhabiting antimicrobial-resistant (AMR) microorganisms as reservoirs of acquired resistance determinants (AMR genes), represents a specific concern from a One Health approach. Here, we present a phenotypic AMR analysis and molecular characterization of Escherichia coli isolate found in municipal drinking water after an accident in the water supply system of a residential building in Armenia in 2021. CrieF1144 E. coli isolate was resistant to ampicillin, ampicillin/sulbactam, cefuroxime, ciprofloxacin, levofloxacin, trimethoprim/sulfamethoxazole, colistin, and tigecycline, whereas whole genome sequencing (WGS) revealed blaTEM-1B, tet(A), and a combination of dfrA14 with sul1 resistance determinants, which corresponds well with phenotypic resistance above. Moreover, the multidrug-resistant isolate studied harbored mcr-1.1 gene on a conjugative 251 Kb IncHI2 plasmid, whose structure was determined using hybrid short- and long-reads assembly. CrieF1141_p1 plasmid carried all antimicrobial resistance genes revealed in the isolate and did not harbor any virulence determinants, so it could contribute to the spread of AMR genes in the bacterial population. Two copies of ISApl1 transposase-encoding element, which is likely to mediate mcr-1.1 gene mobilization, were revealed surrounding this gene in a plasmid.

IMPORTANCE

Evolutionary patterns of Escherichia coli show that they usually develop into highly pathogenic forms by acquiring fitness advantages such as antimicrobial resistance (AMR) and various virulence factors through horizontal gene transfer mediated by mobile elements. This has led to high prevalence of multidrug-resistant (MDR) strains, which highlights the relevancy of enhanced surveillance to monitor and prevent transmission of the MDR bacteria to human and animal populations. However, the limited number of reports regarding the whole genome sequencing (WGS) investigation of MDR E. coli strains isolated from drinking water and harboring mcr genes hampers the adoption of a comprehensive approach to address the relationship between environmental E. coli populations and human and veterinary infections. Our results highlight the relevance of analyzing the environment, especially water, as a part of the surveillance programs to understand the origins and dissemination of antimicrobial resistance within the One Health concept.

CRISPR-Cas System, Antimicrobial Resistance, and Enterococcus Genus-A Complicated Relationship

(1) Background: The rise in antibiotic resistant bacteria poses a significant threat to public health worldwide, necessitating innovative solutions. This study explores the role of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) in the context of antibiotic resistance among different species from the Enterococcus genus. (2) Methods: The genomes of Enterococcus included in the study were analyzed using CRISPRCasFinder to distinguish between CRISPR-positive (level 4 CRISPR) and CRISPR-negative genomes. Antibiotic resistance genes were identified, and a comparative analysis explored potential associations between CRISPR presence and antibiotic resistance profiles in Enterococcus species. (3) Results: Out of ten antibiotic resistance genes found in Enterococcus species, only one, the efmA gene, showed a strong association with CRISPR-negative isolates, while the others did not significantly differ between CRISPR-positive and CRISPR-negative Enterococcus genomes. (4) Conclusion: These findings indicate that the efmA gene may be more prevalent in CRISPR-negative Enterococcus genomes, and they may contribute to a better understanding of the molecular mechanisms underlying the acquisition of antibiotic resistance genes in Enterococcus species.

Gram-negative bacilli carrying mcr gene in Brazil: a pathogen on the rise

The incidence of infections caused by resistant Gram-negative pathogens has become a critical factor in public health due to the limitation of therapeutic options for the control of infections caused, especially, by Enterobacteriaceae (Escherichia coli and Klebsiella pneumoniae), Pseudomonas spp., and Acinetobacter spp. Thus, given the increase in resistant pathogens and the reduction of therapeutic options, polymyxins were reintroduced into the clinic. As the last treatment option, polymyxins were regarded as the therapeutic key, since they were one of the few classes of antimicrobials that had activity against multidrug-resistant Gram-negative bacilli. Nonetheless, over the years, the frequent use of this antimicrobial has led to reports of resistance cases. In 2015, mcr (mobile colistin resistance), a colistin resistance gene, was described in China. Due to its location on carrier plasmids, this gene is characterized by rapid spread through conjugation. It has thus been classified as a rising threat to public health worldwide. In conclusion, based on several reports that show the emergence of mcr in different regional and climatic contexts and species of isolates, this work aims to review the literature on the incidence of the mcr gene in Brazil in different regions, types of samples identified, species of isolates, and type of carrier plasmid.

Molecular Epidemiology of Antimicrobial Resistance and Virulence Profiles of Escherichia coli, Salmonella spp., and Vibrio spp. Isolated from Coastal Seawater for Aquaculture

The occurrence of waterborne antimicrobial-resistant (AMR) bacteria in areas of high-density oyster cultivation is an ongoing environmental and public health threat given the popularity of shellfish consumption, water-related human recreation throughout coastal Thailand, and the geographical expansion of Thailand's shellfish industry. This study characterized the association of phenotypic and genotypic AMR, including extended-spectrum β-lactamase (ESBL) production, and virulence genes isolated from waterborne Escherichia coli (E. coli) (n = 84), Salmonella enterica (S. enterica) subsp. enterica (n = 12), Vibrio parahaemolyticus (V. parahaemolyticus) (n = 249), and Vibrio cholerae (V. cholerae) (n = 39) from Thailand's coastal aquaculture regions. All Salmonella (100.0%) and half of V. cholerae (51.3%) isolates harbored their unique virulence gene, invA and ompW, respectively. The majority of isolates of V. parahaemolyticus and E. coli, ~25% of S. enterica subsp. enterica, and ~12% of V. cholerae, exhibited phenotypic AMR to multiple antimicrobials, with 8.9% of all coastal water isolates exhibiting multidrug resistance (MDR). Taken together, we recommend that coastal water quality surveillance programs include monitoring for bacterial AMR for food safety and recreational water exposure to water for Thailand's coastal water resources.

Genomic Analysis of a Highly Virulent NDM-1-Producing Escherichia coli ST162 Infecting a Pygmy Sperm Whale (Kogia breviceps) in South America

Carbapenemase-producing Enterobacterales are rapidly spreading and adapting to different environments beyond hospital settings. During COVID-19 lockdown, a carbapenem-resistant NDM-1-positive Escherichia coli isolate (BA01 strain) was recovered from a pygmy sperm whale (Kogia breviceps), which was found stranded on the southern coast of Brazil. BA01 strain belonged to the global sequence type (ST) 162 and carried the bla_NDM–1, besides other medically important antimicrobial resistance genes. Additionally, genes associated with resistance to heavy metals, biocides, and glyphosate were also detected. Halophilic behavior (tolerance to > 10% NaCl) of BA01 strain was confirmed by tolerance tests of NaCl minimal inhibitory concentration, whereas halotolerance associated genes katE and nhaA, which encodes for catalase and Na⁺/H⁺ antiporter cytoplasmic membrane, respectively, were in silico confirmed. Phylogenomics clustered BA01 with poultry- and human-associated ST162 lineages circulating in European and Asian countries. Important virulence genes, including the astA (a gene encoding an enterotoxin associated with human and animal infections) were detected, whereas in vivo experiments using the Galleria mellonella infection model confirmed the virulent behavior of the BA01 strain. WHO critical priority carbapenemase-producing pathogens in coastal water are an emerging threat that deserves the urgent need to assess the role of the aquatic environment in its global epidemiology.