RESUMEN
Halomonas hamiltonii is a gram-negative rod bacterium isolated from highly saline environments. H. hamiltonii has rarely been reported as a human pathogen. Herein, we present the first case report of a purulent lymphadenitis caused by H. hamiltonii worldwide. The patient was a previously healthy girl aged 1 year who was referred to our hospital for left axillary lymphadenitis. Although oral amoxicillin was administered, lymphadenitis did not improve, and an abscess developed. After incision and drainage, the abscess was reduced. No recurrence of lymphadenitis was observed. The pus culture was negative. However, the 16S ribosomal DNA was amplified by the melting temperature mapping method. The amplified 16S ribosomal DNA sequence revealed 99.7% identity of H. hamiltonii. To the best of our knowledge, this is the first case of H. hamiltonii infection in a lymph node. This pathogen should be considered when diagnosing purulent lymphadenitis in healthy patients with lymphadenopathy of unknown origin.
Asunto(s)
COVID-19 , Síndrome Mucocutáneo Linfonodular , Humanos , COVID-19/complicaciones , Síndrome Mucocutáneo Linfonodular/complicaciones , Síndrome Mucocutáneo Linfonodular/diagnóstico , SARS-CoV-2 , Síndrome de Respuesta Inflamatoria Sistémica/complicaciones , Síndrome de Respuesta Inflamatoria Sistémica/diagnósticoRESUMEN
Many potent neutralizing SARS-CoV-2 antibodies have been developed and used for therapies. However, the effectiveness of many antibodies has been reduced against recently emerging SARS-CoV-2 variants, especially the Omicron variant. We identified a highly potent SARS-CoV-2 neutralizing antibody, UT28K, in COVID-19 convalescent individuals who recovered from a severe condition. UT28K showed efficacy in neutralizing SARS-CoV-2 in an in vitro assay and in vivo prophylactic treatment, and the reactivity to the Omicron strain was reduced. The structural analyses revealed that antibody UT28K Fab and SARS-CoV-2 RBD protein interactions were mainly chain-dominated antigen-antibody interactions. In addition, a mutation analysis suggested that the emergence of a UT28K neutralization-resistant SARS-CoV-2 variant was unlikely, as this variant would likely lose its competitive advantage over circulating SARS-CoV-2. Our data suggest that UT28K offers potent protection against SARS-CoV-2, including newly emerging variants.