Burkholderia cepacia complex in cystic fibrosis: critical gaps in diagnosis and therapy.

Burkholderia cepacia complex (Bcc) is a bacterial group with 'natural' multi-antimicrobial resistance. This complex has generated epidemic outbreaks across the world. In people with cystic fibrosis (CF), Bcc can cause severe lung infections that lead to accelerated lung damage, which can be complicated by necrotizing pneumonia accompanied by high fevers, leucocytosis, and bacteraemia, which commonly causes fatal outcomes. Specifically, infection by Burkholderia cenocepacia is considered an exclusion criterion for lung transplantation. The species of Bcc exhibit both genetic and phenotypic hypervariability that complicate their accurate microbiological identification. Automated methods such as MALDI-TOF can err in the determination of species. Their slow growth even in selective agars and the absence of international consensuses on the optimal conditions for their isolation make early diagnosis a difficult challenge to overcome. The absence of correlations between antibiograms and clinical results has resulted in the absence of standardized cut-off values of antimicrobial susceptibility, a fact that brings a latent risk since incorrect antibiotic therapy can induce the selection of more aggressive variants that worsen the clinical picture of the host, added to the absence of a clear therapeutic guide for the eradication of pulmonary infections by Bcc in patients with CF, resulting in frequently ineffective treatments. There is an urgent need to standardize methods and diagnostic tools that would allow an early and accurate diagnosis, as well as to perform clinical studies of the effectiveness of available antibiotics to eradicate Bcc infections, which would allow us to establish standardized therapeutic schemes for Bcc-infected patients.

Diagnosis and Therapeutic Strategies Based on Nucleic Acid Aptamers Selected against Pseudomonas aeruginosa: The Challenge of Cystic Fibrosis.

Antimicrobial resistance (AMR) is a rapidly spreading global health problem, and approximately five million deaths associated with AMR pathogens were identified prior to the COVID-19 pandemic. Pseudomonas aeruginosa has developed increasing AMR, and in patients with cystic fibrosis (CF) colonized by this bacterium, rare phenotypes have emerged that complicate the diagnosis and treatment of the hosts, in addition to multiple associated "epidemic strains" with high morbidities and mortalities. The conjugation of aptamers with fluorochromes or nanostructures has allowed the design of new identification strategies for Pseudomonas aeruginosa with detection limits of up to 1 cell ⋅ mL-1 , and the synergy of aptamers with antibiotics, antimicrobial peptides and nanostructures has exhibited promising therapeutic qualities. Some selected aptamers against this bacterium have shown intrinsic antimicrobial activity. However, these aptamers have been poorly evaluated in clinical isolates and have shown decreased interactions for CF isolates, demonstrating, in these cases, uncommon phenotypes resulting from the selective qualities of this disease as well as the great adaptive capacity of the pathogen. Therefore, finding an aptamer or set of aptamers that have the ability to recognize strange phenotypes of this bacillus is crucial in the battle against AMR.

Aptámeros acoplados a nanopartículas para el diagnóstico y tratamiento de las infecciones microbianas / Aptamers coupled to nanoparticles in the diagnosis and treatment of microbial infections

Existen nanopartículas con características antibacterianas destacables y aptámeros capaces de reconocer con gran afinidad y especificidad a determinadas bacterias patógenas. La combinación de ambos sistemas se ha utilizado en el diseño de métodos rápidos de detección bacteriana con excelentes límites de detección. Asimismo, la sinergia entre aptámeros y nanopartículas ha permitido optimizar la actividad antimicrobiana de antibióticos y otras nanoestructuras dotándolos de actividad bacteria-específica, convirtiéndolas en herramientas atractivas y prometedoras frente a las bacterias resistentes a múltiples antimicrobianos

There are nanoparticles with remarkable antibacterial characteristics and aptamers able to recognize specific pathogenic bacteria with high affinity and specificity. The combination of both systems has been used to design rapid bacterial detection methods with excellent detection limits. Likewise, the synergism between aptamers and nanoparticles have allowed to optimize the antimicrobial activity of antibiotics and other nanostructures providing them with activity bacterium-specific, turning into attractive and promising tools to fight against bacteria resistant to multiple antimicrobials

Aptamers coupled to nanoparticles in the diagnosis and treatment of microbial infections. / Aptámeros acoplados a nanopartículas para el diagnóstico y tratamiento de las infecciones microbianas.

There are nanoparticles with remarkable antibacterial characteristics and aptamers able to recognize specific pathogenic bacteria with high affinity and specificity. The combination of both systems has been used to design rapid bacterial detection methods with excellent detection limits. Likewise, the synergism between aptamers and nanoparticles have allowed to optimize the antimicrobial activity of antibiotics and other nanostructures providing them with activity bacterium-specific, turning into attractive and promising tools to fight against bacteria resistant to multiple antimicrobials.

Aislamiento de poblaciones de Serratia marcescens de origen clínico en dos institutos pediátricos / Isolation of populations of Serratia marcescens of clinical origin in two pediatrics institutions

Introudcción. Serratia marcescens es un patógeno oportunista en hospederos inmunocomprometidos y se asocia fundamentalmente a brotes intrahospitalarios con tasas de letalidad elevadas. El propósito del presente estudio fue tipificar 2 poblaciones de S. marcescens de origen clínico aisladas en 2 institutos pediátricos semejantes. Material y métodos. Se empleó el sistema de biotipificación propuesto por Grimont para la caracterización de 65 cepas del Hospital Infantil de México, originalmente clasificadas como Enterobacter sp y 35 cepas del Instituto Nacional de Pediatría aisladas en un brote intrahospitalario. Reesultados. El biogrupo más numeroso en ambas poblaciones fue el A 5/8 y de éste los biotipos A8a y A8b; se observaron variaciones en las proporciones de los biotipos identificados acordes al hospital de aislamiento, así como en los biotipos y patrones de resistencia a los antibióticos en cepas aisladas del mismo pacientes en muestras diferentes. Conclusiones. Del presente estudio se concluye que es importante que en los hospitales se realicen estudios epidemiológicos particulares de sus poblaciones de S. marcescens, pero es más importante aún que se lleve a cabo una correcta identificación de esta bacteria para valorar adecuadamente su importancia como patógeno oportunista en nuestro medio