Background Pseudomonas aeruginosa is an opportunist and versatile organism responsible for infections among immunocompromised hosts. This pathogen has high intrinsic resistance to most antimicrobials, including critical strains due to resistance to carbapenems, a last-resort antibiotic. P. aeruginosa AG1 (PaeAG1) is a Costa Rican high-risk ST-111 strain with resistance to multiple antibiotics, including carbapenems due to the activity of both VIM-2 and IMP-18 metallo-β-lactamases (MBLs). These genes are harbored in two class 1 integrons, belonging to one out of the 57 PaeAG1 genomic islands. However, the genomic context related to these determinants in PaeAG1 and other P. aeruginosa strains is unclear. Thus, we implemented a comparative genomic approach to define and up-date the phylogenetic relationship among complete P. aeruginosa genomes using a pan-genome analysis. We also studied the PaeAG1 genomic islands content in other strains and the architecture of genomic regions around the VIM-2- and IMP-18-carrying integrons. Results With 211 strains, the up-dated P. aeruginosa pan-genome revealed that complete genome sequences are able to separate clones by MLST profile (ST), including a clear ST-111 cluster with PaeAG1. The PaeAG1 genomic islands were found to define a diverse presence/absence pattern among related genomes, but content was related to phylogenetic relationships. Finally, landscape reconstruction of specific genomic regions showed that VIM-2-carrying integron (In59-like) is an old-acquaintance element harbored in a known genomic region completely found in other two ST-111 strains. In addition, PaeAG1 has an exclusive genomic region containing a novel IMP-18-carrying integron (registered as In1666), with an arrangement never reported before. Conclusions We provide new insights about the genomic determinants associated with the resistance to carbapenems in the high-risk PaeAG1 using comparative genomics. With the pan-genome analysis and the comparison of PaeAG1 genomic islands in other strains, it was possible to describe the genomic landscape of the two MBLs-carrying integrons, including an old-acquaintance element carrying VIM-2 and a new IMP-18-carrying integron.

14Tolerance to stress conditions is vital for organismal survival, including bacteria under specific environmental 15 conditions, antibiotics and other perturbations. Some studies have described common modulation and shared 16 genes during stress response to different types of disturbances (termed as perturbome), leading to the idea 17 of a central control at the molecular level. We implemented a robust machine learning approach to identify 18 and describe genes associated with multiple perturbations or perturbome in a Pseudomonas aeruginosa PAO1 19 model. 20Using public transcriptomic data, we evaluated six approaches to rank and select genes: using two 21 methodologies, data single partition (SP method) or multiple partitions (MP method) for training and testing 22 datasets, we evaluated three classification algorithms (SVM Support Vector Machine, KNN K-Nearest neighbor 23 and RF Random Forest). Gene expression patterns and topological features at systems level were include to 24 describe the perturbome elements. 25We were able to select and describe 46 core response genes associated to multiple perturbations in 26 Pseudomonas aeruginosa PAO1 and it can be considered a first report of the P. aeruginosa perturbome. 27Molecular annotations, patterns in expression levels and topological features in molecular networks revealed 28 biological functions of biosynthesis, binding and metabolism, many of them related to DNA damage repair 29 and aerobic respiration in the context of tolerance to stress. We also discuss different issues related to 30 implemented and assessed algorithms, including normalization analysis, data partitioning, classification 31 approaches and metrics. Altogether, this work offers a different and robust framework to select genes using 32 a machine learning approach. 33 34

Se presenta el caso de un paciente de 32 años, con historia de cefaleas de 10 años de evolución, que consulta al Servicio de Emergencias por cuadro subagudo de cefalea, asoció aura visual y parestesia en ambos miembros superiores. Sumado a esto, en la punción lumbar se documentó hipertensión endocraneal y pleocitosis linfocitaria. En el proceso diagnóstico se realizaron estudios que excluyen causas estructurales, vasculares, inflamatorias e infecciosas. De forma paralela, se le brindó tratamiento sintomático, durante el mismo presentó resolución clínica y a nivel de LCR control. El diagnóstico de síndrome de Headache and Neurological Deficits with cerebrospinalfluid Lymphocytosis (HaNDL) se realizó restrospectivamente. Este síndrome es poco frecuente o subdiagnosticado.En general, cursa con un buen pronóstico, a diferencia de sus diagnósticos diferenciales. La comprensión e identificación adecuadas de esta entidad evita complicaciones iatrogénicas.

Pseudomonas aeruginosa is an opportunist and versatile organism responsible for infections mainly in immunocompromised hosts. This pathogen has high intrinsic resistance to most antimicrobials. P. aeruginosa AG1 (PaeAG1) is a Costa Rican high-risk ST-111 strain with resistance to multiple antibiotics, including carbapenems, due to the activity of VIM-2 and IMP-18 metallo-β-lactamases (MBLs). These genes are harbored in two class 1 integrons located inone out of the 57 PaeAG1 genomic islands. However, the genomic context associated to these determinants in PaeAG1 and other P. aeruginosa strains is unclear. Thus, we first assessed the transcriptional activity of VIM-2 and IMP-18 genes when exposed to imipenem (a carbapenem) by RT-qPCR. To select related genomes to PaeAG1, we implemented a pan-genome analysis to define and up-date the phylogenetic relationship among complete P. aeruginosa genomes. We also studied the PaeAG1 genomic islands content in the related strains and finally we described the architecture and possible evolutionary steps of the genomic regions around the VIM-2- and IMP-18-carrying integrons.Expression of VIM-2 and IMP-18 genes was demonstrated to be induced after imipenem exposure. In a subsequent comparative genomics analysis with 211 strains, the P. aeruginosa pan-genome revealed that complete genome sequences are able to separate clones by MLST profile, including a clear ST-111 cluster with PaeAG1. The PaeAG1 genomic islands were found to define a diverse presence/absence pattern among related genomes. Finally, landscape reconstruction of genomic regions showed that VIM-2-carrying integron (In59-like) is an old-acquaintance element harbored in the same known region found in other two ST-111 strains. Also, PaeAG1 has an exclusive genomic region containing a novel IMP-18-carrying integron (registered as In1666), with an arrangement never reported before. Altogether, we provide new insights about the genomic determinants associated with the resistance to carbapenems in this high-risk P. aeruginosa using comparative genomics.

Se presenta el caso de un paciente de 32 años, con historia de cefaleas de 10 años de evolución, que consulta al Servicio de Emergencias por cuadro subagudo de cefalea, asoció aura visual y parestesia en ambos miembros superiores. Sumado a esto, en la punción lumbar se documentó hipertensión endocraneal y pleocitosis linfocitaria. En el proceso diagnóstico se realizaron estudios que excluyen causas estructurales, vasculares, inflamatorias e infecciosas. De forma paralela, se le brindó tratamiento sintomático, durante el mismo presentó resolución clínica y a nivel de LCR control. El diagnóstico de síndrome de Headache and Neurological Deficits with cerebrospinalfluid Lymphocytosis (HaNDL) se realizó restrospectivamente.Este síndrome es poco frecuente o subdiagnosticado. En general, cursa con un buen pronóstico, a diferencia de sus diagnósticos diferenciales. La comprensión e identificación