Insights into macrolide resistance in Arcobacter butzleri: potential resistance mechanisms and impact on bacterial fitness and virulence.

BACKGROUND: Macrolides are recommended for treating the emerging enteropathogen Arcobacter butzleri; nonetheless, this bacterium often exhibits highly variable resistance rates, and the mechanisms behind this resistance phenotype remain largely unexplored. OBJECTIVES: To understand the phenotypic and genotypic consequences associated with the acquisition of erythromycin resistance in A. butzleri, as well as the effects on the fitness of this species. METHODS: Resistant strains resulting from spontaneous mutations and adaptive laboratory evolution under increasing erythromycin concentrations were examined regarding their cross-resistance and collateral susceptibility profiles. Genetic causes of phenotypic antibiotic resistance were analysed by sequencing and bioinformatics, with functional correlation through ethidium bromide accumulation assays. Growth profiles in the presence and absence of erythromycin, motility and biofilm formation abilities were assessed to detect potential changes in fitness and virulence. RESULTS: Clones from spontaneous mutation rate evolution demonstrated decreased susceptibility to erythromycin and other classes of antibiotics, associated with mutations in the transcriptional repressor areR, causing overexpression of the AreABC efflux pump. In turn, WGS analysis of the evolved strain showed additional mutations in the ribosomal proteins L4 and L22 and in the areR gene. Furthermore, the acquisition of macrolide resistance altered A. butzleri virulence and entailed a high biological cost. CONCLUSIONS: The findings of this study have proved that efflux activity contributes synergistically with mutations in the ribosomal proteins L4 and L22 to A. butzleri's high-level macrolide resistance. The results further suggest an impact on the bacterial physiology and virulence, with the increased fitness cost justifying the low worldwide prevalence of high-level resistant circulating strains.

Epidemiological Data and Antimicrobial Resistance of Campylobacter spp. in Portugal from 13 Years of Surveillance.

This study extensively analyzed campylobacteriosis surveillance in Portugal from 2009 to 2021, aiming to investigate demographic shifts, seasonal variations, and antimicrobial resistance (AMR) within Campylobacter isolates. Surveillance network and sentinel laboratory-based system data revealed a substantial under-notification of campylobacteriosis cases, suggesting an underestimated disease burden. Notification rates exhibited a paradigm shift, with a notable prevalence among the pediatric population, particularly in children aged 1-4 years, diverging from European reports. Additionally, an emerging trend of Campylobacter infections in younger adults (15-44 years) was observed. The study unveiled a unique seasonal distribution of cases, defying typical summer peaks seen elsewhere. AMR analysis revealed high resistance to ciprofloxacin and tetracycline, in both C. jejuni (93.7% and 79.2%, respectively) and C. coli (96.5% and 93.2%, respectively), stable throughout the studied period (2013-2021). C. coli exhibited significantly higher resistance to erythromycin, gentamicin, ampicillin and ertapenem compared to C. jejuni (p < 0.001). Multilocus Sequence Typing (MLST) data demonstrated the distribution of resistance markers across diverse sequence types, challenging the notion of a clonal origin for multidrug-resistant isolates. In conclusion, the study highlights the need for enhanced surveillance and raises concerns about alarming AMR levels, recommending the implementation of whole-genome sequencing (WGS)-based surveillance for a deeper comprehension of disease patterns and an evolving AMR landscape.

Genomic study of European Clostridioides difficile ribotype 002/sequence type 8.

Clostridioides difficile has significant clinical importance as a leading cause of healthcare-associated infections, with symptoms ranging from mild diarrhoea to severe colitis, and possible life-threatening complications. C. difficile ribotype (RT) 002, mainly associated with MLST sequence type (ST) 8, is one of the most common RTs found in humans. This study aimed at investigating the genetic characteristics of 537 C. difficile genomes of ST8/RT002. To this end, we sequenced 298 C. difficile strains representing a new European genome collection, with strains from Germany, Denmark, France and Portugal. These sequences were analysed against a global dataset consisting of 1,437 ST8 genomes available through Enterobase. Our results showed close genetic relatedness among the studied ST8 genomes, a diverse array of antimicrobial resistance (AMR) genes and the presence of multiple mobile elements. Notably, the pangenome analysis revealed an open genomic structure. ST8 shows relatively low overall variation. Thus, clonal isolates were found across different One Health sectors (humans, animals, environment and food), time periods, and geographical locations, suggesting the lineage's stability and a universal environmental source. Importantly, this stability did not hinder the acquisition of AMR genes, emphasizing the adaptability of this bacterium to different selective pressures. Although only 2.4 % (41/1,735) of the studied genomes originated from non-human sources, such as animals, food, or the environment, we identified 9 cross-sectoral core genome multilocus sequence typing (cgMLST) clusters. Our study highlights the importance of ST8 as a prominent lineage of C. difficile with critical implications in the context of One Health. In addition, these findings strongly support the need for continued surveillance and investigation of non-human samples to gain a more comprehensive understanding of the epidemiology of C. difficile.

Intersectoral collaboration in a One Health approach: Lessons learned from a country-level simulation exercise.

Intersectoral collaboration is an essential component of the One Health (OH) approach, which recognises the interconnectedness of the health of humans, animals, and the environment. The OH European Joint Programme (OHEJP) developed a national foodborne outbreak table-top simulation exercise (SimEx) to practice OH capacity and interoperability across the public health, animal health, and food safety sectors, improving OH preparedness for future disease outbreaks. The Portuguese OHEJP SimEx highlighted strengths and weaknesses regarding the roles and functions of available systems, the constraints of existing legislation, the importance of harmonisation and data sharing, and the creation of common main messages adapted to each target sector. However, there is still a long way to go to ensure cooperation among the Public Health, Animal Health, and Food Safety sectors, as a OH approach relies not only on the awareness of "field experts" but also on political and organisational willingness and commitment.

A rare cause of vertebral osteomyelitis: the first case report of rat-bite fever in Portugal

Abstract Rat-bite fever is a rarely diagnosed illness caused by Streptobacillus moniliformis . Although this disease is distributed worldwide, there have been few cases reported in Europe. Here, we report a case of vertebral osteomyelitis and sternoclavicular septic arthritis caused by S. moniliformis in a Portuguese patient previously bitten by a rat. Laboratory diagnosis was performed using molecular identification. This is the first case report of rat-bite fever in Portugal. The case described here serves as a reminder for physicians to consider this diagnosis in patients who have developed fever syndromes after being in contact with rodents.