Clinical, microbiological and genomic characterization of Gram-negative bacteria with dual carbapenemases as identified by rapid molecular testing.

Objective: Dual carbapenemase-producing organisms (DCPOs) are an emerging threat that expands the spectrum of antimicrobial resistance. There is limited literature on the clinical and genetic epidemiology of DCPOs. Methods: DCPO isolates were identified by Xpert® Carba-R PCR testing of routine diagnostic cultures performed from 2018 to 2021 at a New York City health system. WGS was performed by Illumina and/or PacBio. Medical records of patients were reviewed for clinical and epidemiological data. Results: Twenty-six DCPO isolates were obtained from 13 patients. Klebsiella pneumoniae (n = 22) was most frequent, followed by Pseudomonas aeruginosa (n = 2), Escherichia coli (n = 1) and Enterobacter cloacae (n = 1). The most common DCPO combination was blaNDM/blaOXA-48-like (n = 16). Notably, 1.05% (24/2290) of carbapenem-resistant Enterobacterales isolates were identified as DCPOs. The susceptibility profiles matched the identified resistance genes, except for a K. pneumoniae (blaKPC/blaOXA-48-like) isolate that was phenotypically susceptible to meropenem. Eleven patients were hospitalized within the year prior to admission, and received antibiotic(s) 1 month prior. Seven patients were originally from outside the USA. Hypertension, kidney disease and diabetes were frequent comorbidities. Death in two cases was attributed to DCPO infection. WGS of eight isolates showed that carbapenemases were located on distinct plasmids, except for one K. pneumoniae isolate where NDM and KPC carbapenemases were located on a single IncC-type plasmid backbone. Conclusions: Here we characterized a series of DCPOs from New York City. Foreign travel, prior hospitalization, antibiotic usage and comorbidities were common among DCPO cases. All carbapenemases were encoded on plasmids, which may facilitate horizontal transfer.

Rhodococcus equi infection after reduction mammaplasty in an immunocompetent patient / Infección por Rhodococcus equi luego de cirugía de reducción mamaria en huésped inmunocompetente

The majority of infections caused by R. equi occur in hosts with some degree of cell-mediated immunodeficiency. Immunocompetent individuals are infrequently affected and usually present with localized disease. Infections of the skin or related structures are uncommon and are usually related to environmental contamination. The microbiology laboratory plays a key role in the identification of the organism since it may be mistaken for common skin flora. We describe a 31 year-old woman without medical problems who presented nine weeks after breast reduction with right breast cellulitis and purulent drainage from the surgical wound. She underwent incision and drainage, and cultures of the wound yielded Rhodococcus equi. The patient completed six weeks of antimicrobial therapy with moxifloxacin and rifampin with complete resolution.

La mayoría de las infecciones causadas por Rhodococcus equi ocurren en huéspedes con algún grado de inmunodeficiencia celular. Los individuos inmunocompetentes son afectados con baja frecuencia y suelen presentarse con enfermedad localizada. Las infecciones de la piel o partes blandas son poco frecuentes y están usualmente relacionadas con contaminación ambiental. El laboratorio de microbiología juega un papel clave en la identificación del organismo, ya que este puede confundirse con flora normal de la piel. Se describe una mujer de 31 años sin problemas médicos que consultó nueve semanas después de haber sido sometida a cirugía de reducción mamaria, con celulitis del seno derecho y drenaje purulento de la herida quirúrgica. Se practicó incisión y drenaje quirúrgico y los cultivos de la herida demostraron R. equi. La paciente recibió seis semanas de tratamiento antimicrobiano con moxifloxacina y rifampicina demostrando resolución completa.