Effect of RecA inactivation and detoxification systems on the evolution of ciprofloxacin resistance in Escherichia coli

Background Suppression of SOS response and overproduction of reactive oxygen species (ROS) through detoxification system suppression enhance the activity of fluoroquinolones. Objectives To evaluate the role of both systems in the evolution of resistance to ciprofloxacin in an isogenic model of Escherichia coli. Methods Single-gene deletion mutants of E. coli BW25113 (wild-type) (ΔrecA, ΔkatG, ΔkatE, ΔsodA, ΔsodB), double-gene (ΔrecA-ΔkatG, ΔrecA-ΔkatE, ΔrecA-ΔsodA, ΔrecA-ΔsodB, ΔkatG-ΔkatE, ΔsodB-ΔsodA) and triple-gene (ΔrecA-ΔkatG-ΔkatE) mutants were included. The response to sudden high ciprofloxacin pressure was evaluated by mutant prevention concentration (MPC). The gradual antimicrobial pressure response was evaluated through experimental evolution and antibiotic resistance assays. Results For E. coli BW25113 strain, ΔkatE, ΔsodB and ΔsodB/ΔsodA mutants, MPC values were 0.25 mg/L. The ΔkatG, ΔsodA, ΔkatG/katE and ΔrecA mutants showed 2-fold reductions (0.125 mg/L). The ΔkatG/ΔrecA, ΔkatE/ΔrecA, ΔsodA/ΔrecA, ΔsodB/ΔrecA and ΔkatG/ΔkatE/ΔrecA strains showed 4–8-fold reductions (0.03–0.06 mg/L) relative to the wild-type. Gradual antimicrobial pressure increased growth capacity for ΔsodA and ΔsodB and ΔsodB/ΔsodA mutants (no growth in 4 mg/L) compared with the wild-type (no growth in the range of 0.5–2 mg/L). Accordingly, increased growth was observed with the mutants ΔrecA/ΔkatG (no growth in 2 mg/L), ΔrecA/ΔkatE (no growth in 2 mg/L), ΔrecA/ΔsodA (no growth in 0.06 mg/L), ΔrecA/ΔsodB (no growth in 0.25 mg/L) and ΔrecA/ΔkatG/ΔkatE (no growth in 0.5 mg/L) compared with ΔrecA (no growth in the range of 0.002–0.015 mg/L). Conclusions After RecA inactivation, gradual exposure to ciprofloxacin reduces the evolution of resistance. After suppression of RecA and detoxification systems, sudden high exposure to ciprofloxacin reduces the evolution of resistance in E. coli.Plan Nacional de I+D+i 2013-2016 and the Instituto de Salud Carlos III (projects and PI17/01501 and PI20-00239)Subdirección General de Redes y Centros de Investigación Cooperativa, Ministerio de Economía, Industria y Competitividad, Spanish Network for Research in Infectious Diseases (REIPI; RD16/0016/0001 and REIPI RD16/ 0016/0009

Outbreaks by Klebsiella oxytoca in neonatal intensive care units: Analysis of an outbreak in a tertiary hospital and systematic review

Objective: Klebsiella oxytoca can cause nosocomial infections, affecting vulnerable newborns. There are few studies describing nosocomial outbreaks in the neonatal intensive care units (NICU). In this study, a systematic review of the literature was carried out to know the main characteristics of these outbreaks and the evolution of one is described. Methods: We conducted a systematic review in the Medline database up to July 2022, and present a descriptive study of an outbreak with 21 episodes in the NICU of a tertiary hospital, between September 2021 and January 2022. Results: 9 articles met the inclusion criteria. The duration of outbreaks was found to be variable, of which 4 (44.4%) lasted for a year or more. Colonization (69%) was more frequent than infections (31%) and the mortality rate was 22.4%. In studies describing sources, the most frequent was the environmental origin (57.1%). In our outbreak there were 15 colonizations and 6 infections. The infections were mild conjunctivitis without sequelae. Molecular typing analysis made it possible to detect 4 different clusters. Conclusions: There is an important variability in the evolution and results of the published outbreaks, highlighting a greater number of colonized, use of PFGE (pulsed-field gel electrophoresis) techniques for molecular typing and implementation of control measures. Finally, we describe an outbreak in which 21 neonates were affected with mild infections, resolved without sequelae and whose control measures were effective.Objetivos: Klebsiella oxytoca puede causar infecciones nosocomiales y afectar a recién nacidos vulnera bles. Existen escasos trabajos que describan brotes nosocomiales en las unidades de cuidados intensivos neonatales (UCIN). En este estudio se realiza una revisión sistemática de la literatura para conocer las características principales de estos brotes y se describe la evolución de uno. Métodos: Se realizó una revisión sistemática en la base de datos Medline hasta julio de 2022, y un estudio descriptivo de un brote con 21 episodios en la UCIN de un hospital de tercer nivel, desde septiembre de 2021 a enero de 2022. Resultados: Nueve artículos cumplían los criterios de inclusión. Se encontró que la duración de los brotes fue variable, y que 4 (44,4%) se prolongaron durante un ano˜ o más. Las colonizaciones (69%) fueron más frecuentes que las infecciones (31%) y la tasa de mortalidad fue del 22,4%. En los estudios que describen las fuentes lo más frecuente fue el origen ambiental (57,1%). En nuestro brote hubo 15 colonizaciones y 6 infecciones. Las infecciones fueron conjuntivitis leves sin secuelas. El análisis mediante tipado molecular permitió detectar 4 clústeres diferentes. Conclusiones: Existe una variabilidad importante en la evolución y resultados de los brotes publicados, destacando un mayor número de colonizados, uso de técnicas de electroforesis en campo pulsado para tipado molecular e implantación de medidas de control. Finalmente, describimos un brote en el que se afectaron 21 neonatos con infecciones leves, resueltas sin secuelas y cuyas medidas para su control resultaron eficaces

Outbreaks by Klebsiella oxytoca in neonatal intensive care units: Analysis of an outbreak in a tertiary hospital and systematic review

[ES] Objetivos: Klebsiella oxytoca puede causar infecciones nosocomiales y afectar a recién nacidos vulnerables. Existen escasos trabajos que describan brotes nosocomiales en las unidades de cuidados intensivos neonatales (UCIN). En este estudio se realiza una revisión sistemática de la literatura para conocer las características principales de estos brotes y se describe la evolución de uno. Métodos: Se realizó una revisión sistemática en la base de datos Medline hasta julio de 2022, y un estudio descriptivo de un brote con 21 episodios en la UCIN de un hospital de tercer nivel, desde septiembre de 2021 a enero de 2022. Resultados: Nueve artículos cumplían los criterios de inclusión. Se encontró que la duración de los brotes fue variable, y que 4 (44,4%) se prolongaron durante un año o más. Las colonizaciones (69%) fueron más frecuentes que las infecciones (31%) y la tasa de mortalidad fue del 22,4%. En los estudios que describen las fuentes lo más frecuente fue el origen ambiental (57,1%). En nuestro brote hubo 15 colonizaciones y 6 infecciones. Las infecciones fueron conjuntivitis leves sin secuelas. El análisis mediante tipado molecular permitió detectar 4 clústeres diferentes. Conclusiones: Existe una variabilidad importante en la evolución y resultados de los brotes publicados, destacando un mayor número de colonizados, uso de técnicas de electroforesis en campo pulsado para tipado molecular e implantación de medidas de control. Finalmente, describimos un brote en el que se afectaron 21 neonatos con infecciones leves, resueltas sin secuelas y cuyas medidas para su control resultaron eficaces.[EN] Objectives: Klebsiella oxytoca can cause nosocomial infections, affecting vulnerable newborns. There are few studies describing nosocomial outbreaks in the neonatal intensive care units (NICU). In this study, a systematic review of the literature was carried out to know the main characteristics of these outbreaks and the evolution of one is described. Methods: We conducted a systematic review in the Medline database up to July 2022, and present a descriptive study of an outbreak with 21 episodes in the NICU of a tertiary hospital, between September 2021 and January 2022. Results: Nine articles met the inclusion criteria. The duration of outbreaks was found to be variable, of which 4 (44.4%) lasted for a year or more. Colonization (69%) was more frequent than infections (31%) and the mortality rate was 22.4%. In studies describing sources, the most frequent was the environmental origin (57.1%). In our outbreak there were 15 colonizations and 6 infections. The infections were mild conjunctivitis without sequelae. Molecular typing analysis made it possible to detect 4 different clusters. Conclusions: There is an important variability in the evolution and results of the published outbreaks, highlighting a greater number of colonized, use of pulsed-field gel electrophoresis (PFGE) techniques for molecular typing and implementation of control measures. Finally, we describe an outbreak in which 21 neonates were affected with mild infections, resolved without sequelae and whose control measures were effective.Peer reviewe

Interhospital Spread of blaVIM-1- and blaCTX-M-15-Producing K. pneumoniae ST15 on an IncR Plasmid in Southern Spain

In 2014–2015, the main CTX-M-15- and OXA-48-producing clone in our region was ST15. Recently, K. pneumoniae ST15 isolates co-producing VIM-1 and CTX-M-15 were detected in several hospitals. The aim was to study the emergence and acquisition of this carbapenemase. Between 2017 and 2019, four hospitals submitted twenty-nine VIM-1- and CTX-M-15-producing K. pneumoniae ST15 isolates to our laboratory. Seven representatives of each XbaI PFGE pulsotype were sequenced using short- and long-read technologies. RAST, CGE databases, and Pathogenwatch were used for resistance determinants and capsule-type analysis. Plasmid comparison was performed with Easyfig2.1. Phylogenetic analysis included other contemporary ST15 isolates from Spain. The 29 isolates were clustered into seven different pulsotypes. The selected genomes, from three hospitals in two different provinces, were clustered together (fewer than 35 alleles) and differed by more than 100 alleles from other ST15 isolates obtained in the region. These seven isolates harbored one IncR plasmid (200–220 kb) with a common backbone and four regions flanked by IS26: one contained blaVIM-1, another contained blaCTX-M-15, the third contained blaOXA-1, and the fourth harbored heavy-metal-tolerance genes. The two initial plasmids, from two different centers, were identical, and rearrangement of four regions was observed in the five subsequent plasmids. Our findings showed the first intercenter dissemination of IncR plasmids carrying blaVIM-1, blaCTX-M-15, and metal-tolerance genes mediated by a new lineage of K. pneumoniae ST15. Two different capture events of the blaVIM-1 gene or different IS26-mediated plasmid rearrangements from a common ancestor may explain plasmid variations.Centro de Investigación Biomédica en Red de Enfermedades Infecciosas RH-0136-2020Instituto de Salud Carlos III RH-0136-2020Junta de Andalucía RH-0136-202