Campylobacter is the leading cause of human bacterial gastroenteritis worldwide and has a major impact on global public health. Whole Genome Sequencing (WGS) is a powerful tool applied in the study of foodborne pathogens. The objective of the present study was to apply WGS to determine the genetic diversity, virulence factors and determinants of antimicrobial resistance of the populations of C. jejuni and C. coli in Peru. A total of 129 Campylobacter strains (108 C. jejuni and 21 C. coli) were sequenced using Illumina Miseq platform. In silico MLST analysis identified a high genetic diversity among those strains with 30 sequence types (STs), several of them within 11 clonal complexes (CC) for C. jejuni, while the strains of C. coli belonged to a single CC with 8 different STs. Phylogeny analysis showed that Peruvian C. jejuni strains were divided into 2 clades with 5 populations, while C. coli formed a single clade with 4 populations. Furthermore, in silico analyses showed the presence of several genes associated with adherence, colonization and invasion among both species: cadF (83.7%), jlpA (81.4%), racR (100%), dnaJ (83.7%), pebA (83.7%), pldA (82.1%), porA (84.5%), ceuE (82.9%), ciaB (78.3%), iamB (86.8%), and flaC (100%). The majority (82.9%) of the Campylobacter strains carried the cdtABC operon which code for cytolethal distending toxin (CDT). Half of them (50.4%) carried genes associated with the presence of T6SS, while the frequency of genes associated with T4SS were relatively low (11.6%). Genetic markers associated with resistance to quinolones, tetracycline (tetO, tetW/N/W), beta-lactamases (blaoxa–61), macrolides (A2075G in 23S rRNA) were found in 94.5, 21.7, 66.7, 6.2, 69.8, and 18.6% of strains, respectively. The cmeABC multidrug efflux operon was present in 78.3% of strains. This study highlights the importance of using WGS in the surveillance of emerging pathogens associated with foodborne diseases, providing genomic information on genetic diversity, virulence mechanisms and determinants of antimicrobial resistance. The description of several Campylobacter genotypes having many virulence factors and resistance to quinolones and tetracyclines circulating in Peru provides important information which helps in the monitoring, control and prevention strategies of this emerging pathogen in our country.

Objetivos. Evaluar la susceptibilidad antimicrobiana in vitro a cloranfenicol (CHL) y ciprofloxacino (CIP) de cepas de Bartonella bacilliformis procedentes de áreas endémicas de la enfermedad de Carrión (EC) en el Perú, mediante tres métodos de laboratorio. Materiales y métodos. Se evaluó la susceptibilidad antimicrobiana a CHL y CIP de 100 cepas de Bartonella bacilliformis, los aislamientos procedieron de pacientes de los departamentos de Ancash, Cusco, Cajamarca, Lima y La Libertad; las cepas se evaluaron mediante: disco difusión, E-Test y dilución en agar. Resultados. El 26% de las cepas de Bartonella bacilliformis evaluadas, presentaron resistencia a CIP y 1% a CHL. Se obtuvieron patrones similares de sensibilidad/resistencia antimicrobiana en los tres métodos utilizados. Conclusiones. Las cepas de Bartonella bacilliformis circulantes en el Perú, presentan elevados niveles de resistencia in vitro a CIP, por lo que se recomienda ampliar la investigación sobre la utilización del fármaco en los esquemas de tratamiento de la EC. Los métodos de E-test y disco difusión resultaron más convenientes para la evaluación de la susceptibilidad antimicrobiana in vitro del microorganismo. Palabras clave: Bartonella bacilliformis; Ciprofloxacino; Cloranfenicol; Pruebas antimicrobianas de difusión por disco; Recuento de dilución agar (fuente: DeCS BIREME). ANTIMICROBIAL RESISTANCE OF Bartonella bacilliformis STRAINS FROM REGIONS ENDEMIC TO BARTONELLOSIS IN PERU ABSTRACT Objectives. To evaluate in vitro antimicrobial susceptibility to chloramphenicol (CHL) and ciprofloxacin (CIP) in strains of Bartonella bacilliformis from areas that are endemic to Bartonellosis in Peru, through three laboratory methods. Materials and methods. Antimicrobial susceptibility to CHL and CIP from 100 strains of Bartonella bacilliformis isolated in patients from the regions of Ancash, Cusco, Cajamarca, Lima and La Libertad were evaluated. Strains were evaluated by: disk diffusion, E-test and agar dilution. Results. 26% of the strains of Bartonella bacilliformis evaluated were resistant to CIP and 1% to CHL. Similar patterns of antimicrobial sensitivity / resistance were obtained in all three methods. Conclusions. Bartonella bacilliformis strains circulating in Peru have high levels of in vitro resistance to CIP, so it is advisable to expand research on the use of drug treatment regimens of the Bartonellosis. The methods of E-test and disk diffusion were the most suitable for assessment in vitro of antimicrobial susceptibility of the microorganism.

Tecnólogo médico; b biólogo; c magister en Microbiología; d doctor en Ciencias Médicas; e magister en Bioquímica, Biología Molecular y Biomedicina; f magister en Bioinformática; g doctor en Bioquímica y Biología Molecular

The presence of amino acid changes in GyrA, GyrB, ParC, ParE, and in a proposed chromosomal chloramphenicol acetyl transferase (CAT), as well as mutations at 23S rRNA, were established by PCR and sequencing in 38 B. bacilliformis clinical isolates from four different areas in Peru. Eighteen out of 24 (75%) isolates showing ciprofloxacin resistance for both disk-diffusion and e-test presented amino acid substitutions in GyrA (G89C, six isolates, A91V, 1 isolate) GyrB (S474F, 10 isolates) or both (GyrA D95N and GyrB S474F, one isolate). Two out of 14 susceptible isolates presented amino acid substitutions at GyrB (S474F) or a double substitution GyrA D95N and GyrB S474F. Of note, ciprofloxacin-resistant isolates were recovered in the four areas studied. No amino acid change was observed at ParC or ParE. Only one isolate showed chloramphenicol resistance, but no alteration was present in either 23S rRNA or CAT. B. bacilliformis resistant to quinolones are extended throughout Peru, with amino acid substitutions at GyrA or GyrB as the main, albeit not exclusive, cause. B. bacilliformis seems to have an apparent facility to develop mutations on GyrB outside the classical positions 91, 95 of GyrA and 85, 88 of ParC.