Pseudomonas aeruginosa Sequence Type 235 is a clone that possesses an extraordinary ability to acquire mobile genetic elements and has been associated with the spread of resistance genes, including genes that encode for carbapenemases. Here, we aim to characterize the genetic platforms involved in resistance dissemination in blaKPC-2-positive P. aeruginosa ST235 in Colombia. In a prospective surveillance study of infections in adult patients attended in five ICUs in five distant cities in Colombia, 58 isolates of P. aeruginosa were recovered, of which, 27 (46.6%) were resistant to carbapenems. The molecular analysis showed that 6 (22.2%) and 4 (14.8%) isolates harboured the blaVIM and blaKPC-2 genes, respectively. The four blaKPC-2-positive isolates showed a similar PFGE pulsotype and belonged to ST235. Complete genome sequencing of a representative ST235 isolate shows a unique chromosomal contig of 7097.241 bp with eight different resistance genes identified and five transposons: a Tn6162-like with ant(2″)-Ia, two Tn402-like with ant(3″)-Ia and blaOXA-2 and two Tn4401b with blaKPC-2. All transposons were inserted into the genomic islands. Interestingly, the two Tn4401b copies harbouring blaKPC-2 were adjacently inserted into a new genomic island (PAGI-17) with traces of a replicative transposition process. This double insertion was probably driven by several structural changes within the chromosomal region containing PAGI-17 in the ST235 background. This is the first report of a double Tn4401b chromosomal insertion in P. aeruginosa, just within a new genomic island (PAGI-17). This finding indicates once again the great genomic plasticity of this microorganism.

Background: Helicobacter pylori is a bacterium associated with gastroduodenal disease and gastric cancer. Empirical therapy in the treatment of H. pylori infection increases the risk of apparition of antimicrobial drug resistance. In a previous report, in H. pylori clinical isolates, resistance rates to commonly used antimicrobial drugs were as follows: metronidazole 82%, clarithromycin 3.8%, and amoxicillin 1.9%. The aim was to establish the variation of resistance rates and the detection of H. pylori genetic mutations isolated from dyspeptic patients. Methods: Antimicrobial susceptibility profiles were performed by the E-test method for metronidazole, clarithromycin, amoxicillin, and tetracycline in 61 clinical isolates. Sequencing was performed to detect mutations associated with resistance to clarithromycin. Results: According to our results, resistance rates found in the 61 isolates were 78.60% for metronidazole and 8.20% for clarithromycin. None of the studied isolates had resistance to tetracycline and amoxicillin. Secondary resistance rates displayed an increase when compared to primary rates for metronidazole (87.50 vs. 77.35%) and for clarithromycin (25.66 vs. 5.66%). Of 5 isolates resistant to clarithromycin, 3 had the A2143G mutation. By comparing the results in this work with previous reports, antimicrobial drug resistance rates did not show major modifications for metronidazole, amoxicillin, and tetracycline during the last 10 years. For clarithromycin, the resistance rate showed a moderate increase; nevertheless, it remains low (<15%) and this change was not statistically significant. Conclusion: Together, all findings in this work indicate that these antimicrobial drugs can still be used as first line of defense on infected patients living in this region of the country.

Background: Helicobacter pylori causes one of the most prevalent chronic bacterial infections worldwide. Data about H. pylori resistance rates to levofloxacin and rifampin (antimicrobials for second-, third- or fourth-line therapy) in Colombia and South America are scarce. The present study aimed to assess levofloxacin and rifampin resistance rates among 61 H. pylori isolates from the western-central region of Colombia and to identify gyrA point mutations associated with levofloxacin resistance. Methods: For this purpose, antimicrobial susceptibility was determined using the E-test method and gyrA mutations in levofloxacin-resistant isolates were identified by PCR amplification followed by DNA sequencing. Results: Resistance rates to levofloxacin and rifampin were 24.6% and 13.1%, respectively. Among the 15 levofloxacin-resistant isolates, 6 (40%) isolates had ≥2 gyrA mutations and 5 of them exhibited high (≥32 mg/L) levofloxacin MICs. In addition, two new mutations (Y90C and V89D) were also detected. Conclusions: Clinically relevant resistance to levofloxacin and rifampin was detected among H. pylori isolates from central-western Colombia. Multiple gyrA mutations were identified in a significant proportion of levofloxacin-resistant isolates and were mainly associated with high MIC values, highlighting the need for regional surveillance to guide eradication therapies.

Helicobacter pylori infects the stomach and/or small intestines in more than half of the human population. Infection with H. pylori is the most common cause of chronic gastritis, which can lead to more severe gastroduodenal pathologies such as peptic ulcer, mucosa-associated lymphoid tissue lymphoma, and gastric cancer. H. pylori infection is particularly concerning in Colombia in South America, where > 80% of the population is estimated to be infected with H. pylori and the rate of stomach cancer is one of the highest in the continent. We compared the antimicrobial susceptibility profiles and short-read genome sequences of five H. pylori isolates obtained from patients diagnosed with gastritis of varying severity (chronic gastritis, antral erosive gastritis, superficial gastritis) in Pereira, Colombia sampled in 2015. Antimicrobial susceptibility tests revealed the isolates to be resistant to at least one of the five antimicrobials tested: four isolates were resistant to metronidazole, two to clarithromycin, two to levofloxacin, and one to rifampin. All isolates were susceptible to tetracycline and amoxicillin. Comparative genome analyses revealed the presence of genes associated with efflux pump, restriction modification systems, phages and insertion sequences, and virulence genes including the cytotoxin genes cagA and vacA. The five genomes represent three novel sequence types. In the context of the Colombian and global populations, the five H. pylori isolates from Pereira were phylogenetically distant to each other but were closely related to other lineages circulating in the country. H. pylori from gastritis of different severity varied in their antimicrobial susceptibility profiles and genome content. This knowledge will be useful in implementing appropriate eradication treatment regimens for specific types of gastritis. Understanding the genetic and phenotypic heterogeneity in H. pylori across the geographical landscape is critical in informing health policies for effective disease prevention and management that is most effective at local and country-wide scales. This is especially important in Colombia and other South American countries that are poorly represented in global genomic surveillance studies of bacterial pathogens.

Introducción: Las infecciones asociadas a la atención en salud (IAAS) son aquellas infecciones que el paciente adquiere mientras recibe tratamiento y en quien la infección no se había manifestado ni estaba en periodo de incubación en el momento de ingreso. Las IAAS son causadas por bacterias, hongos y virus. Por su parte, la resistencia a los antimicrobianos se produce cuando los microorganismos sufren cambios que no permiten la acción de los medicamentos empleados para tratar las infecciones. Debido a esto, la emergencia y rápida diseminación de infecciones por microorganismos resistentes a los antimicrobianos se considera un problema de salud pública que se asocia con la estancia hospitalaria, morbimortalidad y altos costos para el sistema de salud. En adición a esta problemática, las complicaciones infecciosas constituyen una de las causas más importantes de morbimortalidad en los pacientes oncológicos. Actualmente, las mortalidades más altas se encuentran asociadas a enterobacterias y P. aeruginosa. Es por esto, que el conocimiento adecuado de las infecciones en los pacientes oncológicos y su correcto manejo y prevención son determinantes para reducir sus complicaciones. Método: búsqueda de literatura en bases de datos indexadas. Resultados: En esta revisión se discute la importancia del estudio de las IAAS, las principales bacterias Gram negativas causantes de IAAS en pacientes oncológicos, el uso de antimicrobianos y los principales mecanismos de resistencia antimicrobiana.Conclusión: El estudio y entendimiento de la resistencia antimicrobiana en los procesos infecciosos de pacientes oncológicos, como las IAAS, son indispensables para el control, manejo y prevención de estas infecciones, con el fin de mejorar los tratamientos de los pacientes.