This systematic review focuses on obtaining the most relevant information from multiple studies that detected a mobilized colistin resistance mcr gene in Salmonella for a better comprehension of its global distribution. A group of strategic and systematic keywords was combined to retrieve research data on the detection frequency of the mcr gene globally from four database platforms (Google Scholar, Science Direct, PubMed, and Scielo). Forty eight studies attended all the eligibility criteria and were selected. China was the country with the highest frequency of Salmonella strains with the mcr gene, and Europe exhibited a wide diversity of countries with positive mcr strains. Also, animals and humans carried the highest frequency of positive strains for the mcr gene. Salmonella Typhimurium was the most frequent serovar carrying the mcr gene.Apparently, colistin overuse in animal husbandry has increased the selective pressure of antimicrobial resistance, resulting in the emergence of a plasmid-mediated colistin resistance mcr gene in China. The mcr-positive Salmonella strains are recently predominant worldwide, which is probably due to the capacity of this gene to be swiftly horizontally transmissible. The transmission ability of mcr-positive Salmonella strains to humans through the consumption of contaminated animal-based food is a public health concern.

Campylobacter jejuni (C. jejuni) is responsible for 80% of human campylobacteriosis and is the leading cause of gastroenteritis globally. The relevant public health risks of C. jejuni are caused by particular virulence genes encompassing its virulome. We analyzed 40,371 publicly available genomes of C. jejuni deposited in the NCBI Pathogen Detection Database, combining their epidemiologic metadata with an in silico bioinformatics analysis to increase our current comprehension of their virulome from a global perspective. The collection presented a virulome composed of 126 identified virulence factors that were grouped in three clusters representing the accessory, the softcore, and the essential core genes according to their prevalence within the genomes. The multilocus sequence type distribution in the genomes was also investigated. An unexpected low prevalence of the full-length flagellin flaA and flaB locus of C. jejuni genomes was revealed, and an essential core virulence gene repertoire prevalent in more than 99.99% of genomes was identified. Altogether, this is a pioneer study regarding Campylobacter jejuni that has compiled a significant amount of data about the Multilocus Sequence Type and virulence factors concerning their global prevalence and distribution over this database.

In recent years, Campylobacter has become increasingly resistant to antibiotics, especially those first-choice drugs used to treat campylobacteriosis. Studies in South America have reported cases of antibiotic-resistant Campylobacter in several countries, mainly in Brazil. To understand the current frequency of antibiotic-resistant Campylobacter in humans, farm animals, and food of animal origin in South America, we systematically searched for different studies that have reported Campylobacter resistance. The most commonly reported species were C. jejuni and C. coli. Resistance to ciprofloxacin was found to be ubiquitous in the isolates. Nalidixic acid and tetracycline showed a significantly expressed resistance. Erythromycin, the antibiotic of first choice for the treatment of campylobacteriosis, showed a low rate of resistance in isolates but was detected in almost all countries. The main sources of antibiotic-resistant Campylobacter isolates were food of animal origin and farm animals. The results demonstrate that resistant Campylobacter isolates are disseminated from multiple sources linked to animal production in South America. The level of resistance that was identified may compromise the treatment of campylobacteriosis in human and animal populations. In this way, we are here showing all South American communities the need for the constant surveillance of Campylobacter resistance and the need for the strategic use of antibiotics in animal production. These actions are likely to decrease future difficulties in the treatment of human campylobacteriosis.

Salmonella Isangi is an infrequent serovar that has recently been reported in several countries due to nosocomial infections. A considerable number of reports indicate Salmonella Isangi multidrug resistance, especially to cephalosporins, which could potentially pose a risk to public health worldwide. Genomic analysis is an excellent tool for monitoring the emergence of microorganisms and related factors. In this context, the aim of this study was to carry out a genomic analysis of Salmonella Isangi isolated from poultry in Brazil, and to compare it with the available genomes from the Pathogen Detection database and Sequence Read Archive. A total of 142 genomes isolated from 11 different countries were investigated. A broad distribution of extended-spectrum beta-lactamase (ESBL) genes was identified in the Salmonella Isangi genomes examined (blaCTX-M-15, blaCTX-M-2, blaDHA-1, blaNDM-1, blaOXA-10, blaOXA-1, blaOXA-48, blaSCO-1, blaSHV-5, blaTEM-131, blaTEM-1B), primarily in South Africa. Resistome analysis revealed predicted resistance to aminoglycoside, sulfonamide, macrolide, tetracycline, trimethoprim, phenicol, chloramphenicol, and quaternary ammonium. Additionally, PMQR (plasmid-mediated quinolone resistance) genes qnr19, qnrB1, and qnrS1 were identified, along with point mutations in the genes gyrAD87N, gyrAS83F, and gyrBS464F, which confer resistance to ciprofloxacin and nalidixic acid. With regard to plasmids, we identified 17 different incompatibility groups, including IncC, Col(pHAD28), IncHI2, IncHI2A, IncM2, ColpVC, Col(Ye4449), Col156, IncR, IncI1(Alpha), IncFIB (pTU3), Col(B5512), IncQ1, IncL, IncN, IncFIB(pHCM2), and IncFIB (pN55391). Phylogenetic analysis revealed five clusters grouped by sequence type and antimicrobial gene distribution. The study highlights the need for monitoring rare serovars that may become emergent due to multidrug resistance.