RESUMEN
OBJECTIVE: We aimed to describe a colistin (COL)-resistant (R) Chromobacterium violaceum (Cvi) isolate from a septic patient in Argentina expressing a previously unknown gene, blaCVI-1. METHODS: In 2019, a 12 year old child was injured with a thorn in a lagoon. The child was hospitalized due to sepsis and multiple abscesses. Cvi was isolated from skin and soft tissue and tracheal aspirate. The patient was successfully treated with imipenem (IMI) plus amikacin. Antimicrobial susceptibility was assessed by disk diffusion, broth microdilution, and the E-test. Carbapenemase activity was assayed by double-disk synergy and microbiological tests. Resistance, virulence, and additional gene searches were performed by in silico analysis of sequences obtained by whole-genome sequencing (WGS). A maximum likelihood phylogenetic tree was built with public Cvi genomes. RESULTS: R was seen for IMI and COL. Expression of a metallo-ß-lactamase was confirmed. Genome analysis revealed blaCVI-1, a subclass B2 metallo-ß-lactamase with 62.66% ID with CphA from A. hydrophila (WP081086394). R to COL could be attributed to the arnC and arnT genes. Virulence factors required for invasion and toxicity were also found. No plasmids were detected. The phylogeny tree showed two main clades with geographical distinction, and the isolate studied here stands alone in a branch closely related to two clinical isolates from the USA. CONCLUSIONS: This is the second report of infection by Cvi in Argentina. This pathogen carried a new gene, blaCVI-1, a metallo-ß-lactamase that can be detected by routine methods. Prompt suspicion of C. violaceum infection is crucial to treating this rare pathogen rapidly and properly.
RESUMEN
Argentina has two endemic areas of paracoccidioidomycosis (PCM). Bordering Paraguay and Brazil, Northeast Argentina (NEA) comprises the area with the highest incidence where the chronic adult clinical form has historically been reported. Juvenile form in children and adolescents is rare in this area since only one case was reported in the last 10 years. Despite this, between 2010 and 2012, several cases of acute/subacute clinical forms in children aged 10 to 16 (median 12) were detected. In the last decade, the NEA region has been exposed to ecological variations as consequences of certain climatic and anthropogenic changes, including El Niño-Southern Oscillation phenomenon during 2009, and deforestation. The region has also suffered from the significant ecological effects of the construction of one of the biggest hydroelectric dams of South America. This study aims to describe clinical and epidemiological aspects of acute/subacute PCM cases detected in children from NEA and to discuss climatic and anthropogenic changes as possible contributing factors in the emergence of this disease in children. This acute/subacute PCM cluster was characterized by severe disseminated and aggressive presentations to localized form, with a high spectrum of clinical manifestations uncommonly observed. Due to the lack of experience in acute/subacute PCM in children in the studied area and the atypical clinical manifestations observed, the diagnosis was delayed. In order to avoid misdiagnosis, a higher level of suspicion is now required in NEA and countries bordering the southern part of the endemic area, which are affected by the changes discussed in this article.