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Geographic divergence of methicillin-resistant Staphylococcus aureus ST5-SCCmecI in the aftermath of a major earthquake and tsunami: impact of a plasmid harboring heavy metal resistance genes
(American Society for Microbiology, 2025-04-09)
Jose R. W. Martínez
;
Manuel Alcalde-Rico
;
Estefanía Jara-Videla
;
Jinnethe Reyes
;
Lina P. Carvajal
(MRSA) is a major public health menace. The global spread of MRSA is characterized by successive waves of epidemic clones dominating specific geographical regions. The acquisition of genes encoding resistance to heavy metals (HMRGs) is thought to be a key feature in the geographic divergence of MRSA. However, the cause-effect relationship between the presence of HMRGs and the divergence of MRSA clones remains to be clarified. In this study, we assessed the role that HMRGs may have played in the evolutionary divergence of the MRSA ST5-SCC <jats:italic>mec</jats:italic> I lineage in Latin America. We conducted a genomic characterization of 113 MRSA clinical isolates from six Latin American healthcare centers, including 53 isolates collected from two cities in Chile (Santiago and Concepción). We found a plasmid (pSCL4752) harboring arsenic, cadmium, and mercury resistance genes in 65% ( <jats:italic>n</jats:italic> = 71) of the ST5-SCC <jats:italic>mec</jats:italic> I isolates. We also observed a geographic divergence associated with the presence of pSCL4752 in Chilean isolates, with a higher frequency in isolates from Concepción (88%) compared to Santiago (29%). Interestingly, a molecular clock analysis revealed that this divergence occurred in the aftermath of an 8.8 Mw earthquake and tsunami that struck the Concepción area in 2010. Moreover, our results demonstrate that the carriage of pSCL4752 can be beneficial or detrimental for ST5-SCC <jats:italic>mec</jats:italic> I isolates, depending on the environmental availability of these heavy metals. Our results suggest that the divergence of the ST5-SCC <jats:italic>mec</jats:italic> I MRSA lineage in Latin America could have been fostered by environmental disasters and influenced by the presence/absence of HMRGs harbored in a plasmid. </jats:p> <jats:sec> <jats:title>IMPORTANCE</jats:title> <jats:p> Methicillin-resistant <jats:italic>Staphylococcus aureus</jats:italic> (MRSA) is a major cause of life-threatening infections worldwide and a growing public health concern. The rise of antibiotic-resistant bacteria, such as MRSA, is often linked to genetic adaptations that enhance their survival. Our research sheds light on how environmental changes, such as those triggered by a natural disaster, can influence the evolution and geographic spread of a highly resistant MRSA lineage in Latin America. We identified a plasmid carrying genes for resistance to arsenic, cadmium, and mercury, which was associated with the geographic divergence of the ST5-SCC <jats:italic>mec</jats:italic> I MRSA lineage, with striking differences in its prevalence between regions affected by a major earthquake and tsunami. By linking environmental events to pathogen evolution, our study highlights the role of ecological pressures in the spread of MRSA. These findings emphasize the need to integrate environmental monitoring into public health strategies to better understand the global challenge of antimicrobial resistance.
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New Dermoscopy Pattern in Nevus‐Associated Melanomas
(Wiley, 2025-04-19)
Nelson Lobos‐Guede
;
Dan Hartmann
;
Valentina Darlic
;
Cristina Carrera
;
Llucia Alos
Melanomas can appear de novo or in association with a pre‐existing nevus. The association of melanomas with pre‐existing nevi and its role as a melanoma precursor is a controversial issue. Dermoscopy can increase melanoma's diagnostic accuracy and help us suspect nevus‐associated melanomas (NAM). Differentiating NAMs clinically and dermoscopically can be challenging. There are few published studies so far describing dermoscopic features of NAM that have differentiated from <jats:italic>de novo</jats:italic> melanomas, such as multi‐component pattern, multifocal pigmentation, atypical pigment network, regression structures, negative pigment network, irregular globules, and streaks. Here, we report four acquired compound NAMs showing a starburst pattern (SP) within the lesion. No publications have reported NAMs with melanoma components in the form of SP arising within the center of the lesion. Therefore, when faced with a compound or intradermal nevus with incipient central reticulated pigmentation, especially if there is no history of trauma or previous surgery, we must pay alert to the possibility of an early development of melanoma.
2
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Multiomics dissection of human RAG deficiency reveals distinctive patterns of immune dysregulation but a common inflammatory signature
(American Association for the Advancement of Science (AAAS), 2025-01-10)
Marita Bosticardo
;
Kerry Dobbs
;
Ottavia M. Delmonte
;
Andrew J. Martins
;
Francesca Pala
<jats:p> Human recombination-activating gene (RAG) deficiency can manifest with distinct clinical and immunological phenotypes. By applying a multiomics approach to a large group of <jats:italic>RAG</jats:italic> -mutated patients, we aimed at characterizing the immunopathology associated with each phenotype. Although defective T and B cell development is common to all phenotypes, patients with hypomorphic <jats:italic>RAG</jats:italic> variants can generate T and B cells with signatures of immune dysregulation and produce autoantibodies to a broad range of self-antigens, including type I interferons. T helper 2 (T <jats:sub>H</jats:sub> 2) cell skewing and a prominent inflammatory signature characterize Omenn syndrome, whereas more hypomorphic forms of RAG deficiency are associated with a type 1 immune profile both in blood and tissues. We used cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq) analysis to define the cell lineage–specific contribution to the immunopathology of the distinct RAG phenotypes. These insights may help improve the diagnosis and clinical management of the various forms of the disease. </jats:p>
Scopus© Citations 2 1
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Histiocitosis de Erdheim Chester como desafío diagnóstico ante un cuadro sistémico: Reporte de un caso
(2024)
Dominga García
;
Yorman Flores
;
Maximiliano Vergara
;
Cristian Labarca Solar
Scopus© Citations 1
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Prenatal presentation of pleuropulmonary blastoma associated to DICER1 syndrome: differential diagnosis of congenital pulmonary malformation
(2023)
Valenzuela, Catalina Catán
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Paula Vargas Innocenti
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Gutierrez, Aquiles Hachim
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Pinto, Pablo Jorquera
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Ramos, Ximena Claverie
3Scopus© Citations 2
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<i>PUF60</i>‐related developmental disorder: A case series and phenotypic analysis of 10 additional patients with monoallelic <i>PUF60</i> variants
(2023)
H. Grimes
;
M. Ansari
;
T. Ashraf
;
Anna Mª. Cueto‐González
;
A. Calder
<jats:title>Abstract</jats:title><jats:p><jats:italic>PUF60</jats:italic>‐related developmental disorder (also referred to as Verheij syndrome), resulting from haploinsufficiency of <jats:italic>PUF60</jats:italic>, is associated with multiple congenital anomalies affecting a wide range of body systems. These anomalies include ophthalmic coloboma, and congenital anomalies of the heart, kidney, and musculoskeletal system. Behavioral and intellectual difficulties are also observed. While less common than other features associated with <jats:italic>PUF60</jats:italic>‐related developmental disorder, for instance hearing impairment and short stature, identification of specific anomalies such as ophthalmic coloboma can aid with diagnostic identification given the limited spectrum of genes linked with this feature. We describe 10 patients with <jats:italic>PUF60</jats:italic> gene variants, bringing the total number reported in the literature, to varying levels of details, to 56 patients. Patients were recruited both via locally based exome sequencing from international sites and from the DDD study in the United Kingdom. Eight of the variants reported were novel <jats:italic>PUF60</jats:italic> variants. The addition of a further patient with a reported c449‐457del variant to the existing literature highlights this as a recurrent variant. One variant was inherited from an affected parent. This is the first example in the literature of an inherited variant resulting in <jats:italic>PUF60</jats:italic>‐related developmental disorder. Two patients (20%) were reported to have a renal anomaly consistent with 22% of cases in previously reported literature. Two patients received specialist endocrine treatment. More commonly observed were clinical features such as: cardiac anomalies (40%), ocular abnormalities (70%), intellectual disability (60%), and skeletal abnormalities (80%). Facial features did not demonstrate a recognizable gestalt. Of note, but remaining of unclear causality, we describe a single pediatric patient with pineoblastoma. We recommend that stature and pubertal progress should be monitored in <jats:italic>PUF60</jats:italic>‐related developmental disorder with a low threshold for endocrine investigations as hormone therapy may be indicated. Our study reports an inherited case with <jats:italic>PUF60</jats:italic>‐related developmental disorder which has important genetic counseling implications for families.</jats:p>
Scopus© Citations 5 1
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Understanding the phenotypic variability in Niemann-Pick disease type C (NPC): a need for precision medicine
(2023)
Macarena Las Heras
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Benjamín Szenfeld
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Rami A. Ballout
;
Emanuele Buratti
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Silvana Zanlungo
<jats:title>Abstract</jats:title><jats:p>Niemann-Pick type C (NPC) disease is a lysosomal storage disease (LSD) characterized by the buildup of endo-lysosomal cholesterol and glycosphingolipids due to loss of function mutations in the <jats:italic>NPC1</jats:italic> and <jats:italic>NPC2</jats:italic> genes. NPC patients can present with a broad phenotypic spectrum, with differences at the age of onset, rate of progression, severity, organs involved, effects on the central nervous system, and even response to pharmacological treatments. This article reviews the phenotypic variation of NPC and discusses its possible causes, such as the remaining function of the defective protein, modifier genes, sex, environmental cues, and splicing factors, among others. We propose that these factors should be considered when designing or repurposing treatments for this disease. Despite its seeming complexity, this proposition is not far-fetched, considering the expanding interest in precision medicine and easier access to multi-omics technologies.</jats:p>
Scopus© Citations 7 2
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Whole-genome sequencing reveals changes in genomic diversity and distinctive repertoires of T3SS and T6SS effector candidates in Chilean clinical Campylobacter strains
(2023)
Assaf Katz
;
Lorena Porte
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WEITZEL, THOMAS
;
Carmen Varela
;
Cristina Muñoz-Rehbein
<jats:p><jats:italic>Campylobacter</jats:italic> is the leading cause of bacterial gastroenteritis worldwide and an emerging and neglected pathogen in South America. This zoonotic pathogen colonizes the gastrointestinal tract of a wide range of mammals and birds, with poultry as the most important reservoir for human infections. Apart from its high morbidity rates, the emergence of resistant strains is of global concern. The aims of this work were to determine genetic diversity, presence of antimicrobial resistance determinants and virulence potential of <jats:italic>Campylobacter</jats:italic> spp. isolated from patients with acute gastrointestinal disease at ‘Clinica Alemana’, Santiago de Chile. The study considered the isolation of <jats:italic>Campylobacter</jats:italic> spp., from stool samples during a 20-month period (January 2020 to September 2021). We sequenced (NextSeq, Illumina) and performed an in-depth analysis of the genome sequences of 88 <jats:italic>Campylobacter jejuni</jats:italic> and 2 <jats:italic>Campylobacter</jats:italic> coli strains isolated from clinical samples in Chile. We identified a high genetic diversity among C. je<jats:italic>juni</jats:italic> strains and the emergence of prevalent clonal complexes, which were not identified in our previous reports. While ~40% of strains harbored a mutation in the gyrA gene associated with fluoroquinolone resistance, no macrolide-resistance determinants were detected. Interestingly, gene clusters encoding virulence factors such as the T6SS or genes associated with long-term sequelae such as Guillain-Barré syndrome showed lineage-relatedness. In addition, our analysis revealed a high degree of variability regarding the presence of fT3SS and T6SS effector proteins in comparison to type strains 81-176, F38011, and NCTC 11168 and 488. Our study provides important insights into the molecular epidemiology of this emerging foodborne pathogen. In addition, the differences observed regarding the repertoire of fT3SS and T6SS effector proteins could have an impact on the pathogenic potential and transmissibility of these Latin American isolates, posing another challenge in characterizing the infection dynamics of this emergent and neglected bacterial pathogen.</jats:p>
29Scopus© Citations 8
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Glucocerebrosidase mutations disrupt the lysosome and now the mitochondria
(2023)
Andrés D. Klein
;
Tiago Fleming Outeiro
1Scopus© Citations 19
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Connexins in Cancer, the Possible Role of Connexin46 as a Cancer Stem Cell-Determining Protein
(2023)
Isidora M. León-Fuentes
;
María G. Salgado-Gil
;
María S. Novoa
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RETAMAL LUCERO, MAURICIO ANTONIO
<jats:p>Cancer is a widespread and incurable disease caused by genetic mutations, leading to uncontrolled cell proliferation and metastasis. Connexins (Cx) are transmembrane proteins that facilitate intercellular communication via hemichannels and gap junction channels. Among them, Cx46 is found mostly in the eye lens. However, in pathological conditions, Cx46 has been observed in various types of cancers, such as glioblastoma, melanoma, and breast cancer. It has been demonstrated that elevated Cx46 levels in breast cancer contribute to cellular resistance to hypoxia, and it is an enhancer of cancer aggressiveness supporting a pro-tumoral role. Accordingly, Cx46 is associated with an increase in cancer stem cell phenotype. These cells display radio- and chemoresistance, high proliferative abilities, self-renewal, and differentiation capacities. This review aims to consolidate the knowledge of the relationship between Cx46, its role in forming hemichannels and gap junctions, and its connection with cancer and cancer stem cells.</jats:p>
Scopus© Citations 3 2

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