Effect of salinity on genes involved in the stress response in mangrove soils.

Mangroves are a challenging ecosystem for the microorganisms that inhabit them, considering they are subjected to stressful conditions such as high and fluctuating salinity. Metagenomic analysis of mangrove soils under contrasting salinity conditions was performed at the mouth of the Ranchera River to the Caribbean Sea in La Guajira, Colombia, using shotgun sequencing and the Illumina Hiseq 2500 platform. Functional gene analysis demonstrated that salinity could influence the abundance of microbial genes involved in osmoprotectant transport, DNA repair, heat shock proteins (HSP), and Quorum Sensing, among others. In total, 135 genes were discovered to be linked to 12 pathways. Thirty-four genes out of 10 pathways had statistical differences for a p-value and FDR < 0.05. UvrA and uvrB (nucleotide excision repair), groEL (HSP), and secA (bacterial secretion system) genes were the most abundant and were enriched by high salinity. The results of this study showed the prevalence of diverse genetic mechanisms that bacteria use as a response to survive in the challenging mangrove, as well as the presence of various genes that are recruited in order to maintain bacterial homeostasis under conditions of high salinity.

Genomic surveillance of the Lambda SARS-CoV-2 variant in a global phylogenetic context.

The massive sequencing of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and global genomic surveillance strategies allowed the detection of many variants of concern and interest. The variant of interest Lambda (C.37), which originated in South America, has been the most prevalent in Peru and Chile, but its dispersion in other continents still remains unknown. The current study aims to determine the phylogenetic relationship among C.37 isolates worldwide, focusing on spike mutations to understand the spread of Lambda in pandemics. A total of 7441 sequences identified as C.37 were downloaded from the GISAID database; local analysis was carried out to identify spike mutations and phylogenetic analysis was carried out to determine the rate of spread of the virus. Our results showed some spike mutations of Lambda that allowed us to detect small local outbreaks in different countries that occurred in the past and identify several clades that have not yet been designated. Although the lineage C.37 is not epidemiologically relevant in Europe or North America, the endemic behavior of this variant in Peru had a major impact on the second SARS-CoV-2 wave.

Response to comment on "genetic variants and source of introduction of SARS-CoV-2 in South America".

During a pandemic, science needs data to generate helpful evidence, and researchers assume this responsibility despite the risk of potential bias. This is the response to the comment made by Pedro Romero, who argued that our manuscript did not use reassembling and mapping strategies for corroborating mutations, and lacked bootstrap support in the phylogenetic analysis.

Genomic analysis reveals a rapid spread and predominance of lambda (C.37) SARS-COV-2 lineage in Peru despite circulation of variants of concern.

The pandemic generated by SARS-Cov-2 has caused a large number of cases and deaths in the world, but South America has been one of the continents that were most hard hit. The appearance of new variants causes concern because of the possibility that they may evade the protection generated by vaccination campaigns, their greater capacity to be transmitted, or their higher virulence. We analyzed the circulating variants in Peru after improving our Genomic Surveillance program. The results indicate a steep increase of the lambda lineage (C.37) until becoming predominant between January and April 2021, despite the cocirculation of other variants of concern or interest. Lambda lineage deserves close monitoring and could probably become a variant of concern in the near future.

Genetic variants and source of introduction of SARS-CoV-2 in South America.

After more than 4 months of the COVID-19 pandemics with genomic information of SARS-CoV-2 around the globe, there are more than 1000 complete genomes of this virus. We used 691 genomes from the GISAID database. Several studies have been reporting mutations and hotspots according to viral evolution. Our work intends to show and compare positions that have variants in 30 complete viral genomes from South American countries. We classified strains according to point alterations and portray the source where strains came into this region. Most viruses entered South America from Europe, followed by Oceania. Only Chilean isolates demonstrated a relationship with Asian isolates. Some changes in South American genomes are near to specific domains related to viral replication or the S protein. Our work contributes to the global understanding of which sort of strains are spreading throughout South America, and the differences among them according to the first isolates introduced to this region.

Trends in antimicrobial resistance of Shigella species in Peru, 2011-2020.

Objective: To describe the frequency of antimicrobial resistance rates and spatial-temporal distribution of Shigella species from the last 10 years in Peru. Methods: A cross-sectional descriptive study was carried out. A total of 1668 Shigella strains, remitted as part of the national enteric pathogen surveillance from 2011 to 2020, were analysed. The strains were confirmed by conventional tests and serotyped with polyvalent and monovalent antibodies. Also, antimicrobial susceptibility was performed according to the Kirby-Bauer method. Results: The most frequent Shigella species was S. sonnei (49.2%), followed by S. flexneri (42.2%), S. boydii (7.9%) and S. dysenteriae (0.7%). Phase II (46.29%) was the most frequent serotype in S. sonnei, serotype 2a (43.61%) in S. flexneri, serotype 2 in S. boydii and serotype 4 in S. dysenteriae. High rates of resistance were detected for trimethoprim/sulfamethoxazole (91.0%), tetracycline (88.4%), ampicillin (73.9%) and chloramphenicol (64.9%), moderate rates for amoxicillin/clavulanic acid (25.1%), ciprofloxacin (16.7%) and nalidixic acid (14.8%), and low rates for cefotaxime (1.74%), nitrofurantoin (0.7%) and ceftazidime (0.6%). Moreover, antimicrobial resistance to fluoroquinolones increased considerably from 2017 to 2020. Conclusion: S. sonnei was the most frequent species, which have a large proportion of strains resistant to trimethoprim/sulfamethoxazole, and a growing trend of resistance to ciprofloxacin and nalidixic acid. This increase in resistance to commonly used antibiotics in treatments is alarming, threatening the control and management of these currently treatable infections.

Emergence and Molecular Epidemiology of Campylobacter jejuni ST-2993 Associated with a Large Outbreak of Guillain-Barré Syndrome in Peru.

Campylobacter jejuni infection is considered the most frequent factor associated with Guillain-Barré syndrome (GBS). In 2019, a large outbreak of GBS was detected in Peru, being associated with C. jejuni detected in stool samples from these patients. The aim of this study was to determine the molecular epidemiology of C. jejuni strains (ST-2993) associated with a large GBS outbreak in Peru. In this study, 26 C. jejuni strains belonging to the ST-2293, obtained from 2019 to 2020, were sequenced using Illumina technology. Five low-quality sequences were removed using bioinformatics, and 21 genomes (17 clinical strains and 4 chicken strains) were considered in the phylogenetic analysis and comparative genomics. Phylogenetic reconstruction, including genomes from international databases, showed a connection between Peruvian and Chinese GBS strains, both of them having lipooligosaccharides (LOS) locus genes related to molecular mimicry with gangliosides in peripheral nerves. Also, ST-2993 was detected in Amazon strains recovered many years before the 2019 outbreak, but with no epidemiological connection with GBS. Besides, a close relationship between human and chicken C. jejuni strains indicated chicken as one of the probable reservoirs. Finally, comparative genomics revealed differences between Chinese and Peruvian strains, including the presence of a prophage inserted into the genome. In conclusion, C. jejuni ST-2993 strains recovered from the GBS outbreak are closely related to Peruvian Amazon strains. Moreover, ST-2993 has been circulated in Peru since 2003 in the Peruvian Amazonia, showing the necessity to reinforce the epidemiological surveillance of C. jejuni to improve the prevention and control of future GBS outbreaks. IMPORTANCE This article describes the molecular epidemiology of C. jejuni strains (ST-2993) associated with a large Guillain-Barré Syndrome (GBS) outbreak in Peru, sequencing several strains recovered from GBS patients and chickens from 2019 to 2020. Phylogenetic analysis showed a connection between Peruvian and Chinese GBS strains, both of them having lipooligosaccharides (LOS) locus genes related to molecular mimicry with gangliosides in peripheral nerves. Also, ST-2993 strains were detected in isolates recovered many years before the 2019 outbreak, but with no epidemiological connection with GBS. Besides, a close relationship between human and chicken strains indicated those animals as a probable reservoir. This information will help to understand the real situation of GBS in Peru and its causal agent, C. jejuni ST-2993, showing the necessity to increase epidemiological tracking of these kinds of pathogens to detect them and avoid GBS outbreaks in the future.

WGS-Based Lineage and Antimicrobial Resistance Pattern of Salmonella Typhimurium Isolated during 2000-2017 in Peru.

Salmonella Typhimurium is associated with foodborne diseases worldwide, including in Peru, and its emerging antibiotic resistance (AMR) is now a global public health problem. Therefore, country-specific monitoring of the AMR emergence is vital to control this pathogen, and in these aspects, whole genome sequence (WGS)­based approaches are better than gene-based analyses. Here, we performed the antimicrobial susceptibility test for ten widely used antibiotics and WGS-based various analyses of 90 S. Typhimurium isolates (human, animal, and environment) from 14 cities of Peru isolated from 2000 to 2017 to understand the lineage and antimicrobial resistance pattern of this pathogen in Peru. Our results suggest that the Peruvian isolates are of Typhimurium serovar and predominantly belong to sequence type ST19. Genomic diversity analyses indicate an open pan-genome, and at least ten lineages are circulating in Peru. A total of 48.8% and 31.0% of isolates are phenotypically and genotypically resistant to at least one antibiotic, while 12.0% are multi-drug resistant (MDR). Genotype−phenotype correlations for ten tested drugs show >80% accuracy, and >90% specificity. Sensitivity above 90% was only achieved for ciprofloxacin and ceftazidime. Two lineages exhibit the majority of the MDR isolates. A total of 63 different AMR genes are detected, of which 30 are found in 17 different plasmids. Transmissible plasmids such as lncI-gamma/k, IncI1-I(Alpha), Col(pHAD28), IncFIB, IncHI2, and lncI2 that carry AMR genes associated with third-generation antibiotics are also identified. Finally, three new non-synonymous single nucleotide variations (SNVs) for nalidixic acid and eight new SNVs for nitrofurantoin resistance are predicted using genome-wide association studies, comparative genomics, and functional annotation. Our analysis provides for the first time the WGS-based details of the circulating S. Typhimurium lineages and their antimicrobial resistance pattern in Peru.

Confirmed Severe Acute Respiratory Syndrome Coronavirus 2 Reinfections After a Second Wave With Predominance of Lambda in Lima and Callao, Peru.

Background: Coronavirus disease 2019 (COVID-19) infection is a major public health problem in the world and reinfections are becoming more frequent. Our main objective was to describe the epidemiological, clinical, and genomic characteristics of the confirmed cases of reinfection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the capital of Lima and Callao, Peru. Methods: We searched in the Peruvian laboratory information system from April 2020 up to May 2021, looking for cases having 2 positive molecular tests for SARS-CoV-2 with more than 90 days between them. We performed genomic sequencing to the available pairs of samples and described the clinical characteristics, epidemiological impact, and genomic analysis of the confirmed reinfections. Results: There were 1 694 164 people with a positive diagnostic test for SARS-CoV-2 in Lima/Callao during the study period. Of these, 1695 had 2 positive molecular tests with more than 90 days between them. Two hundred eleven had both samples available for genomic analysis according to our selection criteria, and these were retrieved and submitted to sequencing. Thirty cases were confirmed to be SARS-CoV-2 reinfections with 2 different lineages in the 2 episodes. The variant Lambda (C.37) was the most common during the second infection and accounted for 19 (63.3%) of the 30 cases. Conclusions: We report 30 cases of confirmed SARS-CoV-2 reinfections. The Lambda variant was the most common cause of the second infections, in concordance with its predominant circulation during Peru's second wave. This report describes the largest series of confirmed reinfections by SARS-CoV-2 in Latin America.We describe the epidemiological, clinical, and genomic characteristics of the confirmed cases of reinfection by severe acute respiratory syndrome coronavirus 2 in Lima and Callao, durante la segunda ola en Peru. The Lambda variant (C.37) was the most common cause of the second infections.

First Report of SARS-CoV-2 Lineage B.1.1.7 (Alpha Variant) in Ecuador, January 2021.

On January 5 2021, Ecuadorian COVID-19 genomic surveillance program detected a suspicious case of the B.1.1.7 lineage (alpha variant) of SARS-CoV-2 in Los Rios province, later confirmed by genome sequencing. The patient travelled from the UK by the end of December 2020. By contact tracing, several new cases were detected confirming B.1.1.7 transmission and spreading in Ecuador.

Genomic epidemiology of SARS-CoV-2 transmission lineages in Ecuador.

Characterisation of SARS-CoV-2 genetic diversity through space and time can reveal trends in virus importation and domestic circulation, and permit the exploration of questions regarding the early transmission dynamics. Here we present a detailed description of SARS-CoV-2 genomic epidemiology in Ecuador, one of the hardest hit countries during the early stages of the COVID-19 pandemic. We generate and analyse 160 whole genome sequences sampled from all provinces of Ecuador in 2020. Molecular clock and phylgeographic analysis of these sequences in the context of global SARS-CoV-2 diversity enable us to identify and characterise individual transmission lineages within Ecuador, explore their spatiotemporal distributions, and consider their introduction and domestic circulation. Our results reveal a pattern of multiple international importations across the country, with apparent differences between key provinces. Transmission lineages were mostly introduced before the implementation of non-pharmaceutical interventions (NPIs), with differential degrees of persistence and national dissemination.

Genomic epidemiology of SARS-CoV-2 transmission lineages in Ecuador.

Characterisation of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) genetic diversity through space and time can reveal trends in virus importation and domestic circulation and permit the exploration of questions regarding the early transmission dynamics. Here, we present a detailed description of SARS-CoV-2 genomic epidemiology in Ecuador, one of the hardest hit countries during the early stages of the coronavirus-19 pandemic. We generated and analysed 160 whole genome sequences sampled from all provinces of Ecuador in 2020. Molecular clock and phylogeographic analysis of these sequences in the context of global SARS-CoV-2 diversity enable us to identify and characterise individual transmission lineages within Ecuador, explore their spatiotemporal distributions, and consider their introduction and domestic circulation. Our results reveal a pattern of multiple international importations across the country, with apparent differences between key provinces. Transmission lineages were mostly introduced before the implementation of non-pharmaceutical interventions, with differential degrees of persistence and national dissemination.

Molecular diversity in pathogenic variants of vibrio parahaemolyticus in Peru. / Diversidad molecular de variantes patogénicas de Vibrio parahaemolyticus en el Perú.

During the period from 1995 to 2017, in order to determine the diversity of Vibrio parahaemolyticus pathogenic variants in Peru, 102 Peruvian genomes (97 from a hospital setting and 5 from an out-of-hospital setting) were analyzed using the multilocus typification scheme and BLASTn in the search for virulence genes. Fifteen different sequence types were identified. It was found that the ST3 genotype, which is found in the pandemic clone, was the most abundant, with 52% (n=53); followed by ST120, with 23.5% (n=24); and the CC345 clonal complex, with 11.8% (n=12). A total of 89 analyzed strains presented genes encoding the pathogenicity island VpaI-7 (87.3%), while 96 presented the tdh gene (94.1%), and 6 the trh gene (5.9%). The ST3 genotype was the predominant one during the evaluated period, this genotype was the cause of a major outbreak in Peru's past history. Other pathogenic genotypes found represent a latent public health risk associated with seafood consumption.

Con el objetivo de determinar la diversidad de variantes patogénicas de Vibrio parahaemolyticus en el Perú durante el periodo 1995-2017, se analizaron 102 genomas peruanos (97 clínicos y 5 ambientales) empleando el esquema de tipificación multilocus y BLASTn para la búsqueda de genes de virulencia. Se identificaron 15 tipos de secuencia diferentes, encontrándose que el genotipo ST3, perteneciente al clon pandémico, fue el más abundante, con 52% (n=53); seguido por el ST120, con 23,5% (n=24); y el complejo clonal CC345, con 11,8% (n=12). Un total de 89 cepas analizadas presentaron genes que codifican la isla de patogenicidad VpaI-7 (87,3%), mientras que 96 presentaron el gen tdh (94,1%), y 6, el trh (5,9%). Durante el periodo evaluado, se resalta la predominancia del ST3, causante de un importante brote en el pasado del Perú, además de otros genotipos patógenos que representan un riesgo latente en salud pública asociado al consumo de alimentos marinos.

Resistome and comparative genomics of clinical isolates of diarrheagenic Escherichia coli from Lima, Peru. / Resistoma y genómica comparativa de aislados clínicos de Escherichia coli diarreogénica en Lima, Perú.

In order to describe the genomic characteristics related to antimicrobial resistance and comparative genomics of diarrheagenic Escherichia coli (DEC), 14 DEC isolates from the strain collection of the Instituto Nacional de Salud (INS) were subjected to genome sequencing. We used bioinformatic procedures to analyze the obtained sequences in order to look for microbial resistance genes and genetic regions related to pathotypes and phylogroups. Several antimicrobial resistance determinants were detected, but the production of beta-lactamases and mutations associated to quinolone resistance were the most relevant. Additionally, we observed isolates of the same pathotype grouped in different phylogroups. The comparative genomics analysis showed a greater number of orthologous genes in isolates from the same pathotype and phylogroup. In conclusion, DEC isolates from Lima, Peru, showed resistance to multiple drugs; likewise, molecular and phylogenetic diversity was observed in several pathotypes and phylogroups.

Con el objetivo de describir las características genómicas relacionadas con la resistencia antimicrobiana y genómica comparativa de Escherichia coli diarreogénica (DEC), se sometieron a secuenciamiento genómico catorce aislamientos de DEC del banco de cepas del Instituto Nacional de Salud (INS). Las secuencias obtenidas se analizaron mediante procedimientos bioinformáticos a fin de buscar genes de resistencia microbiana y regiones genéticas relacionadas con patotipos y filogrupos. Se detectaron diversos determinantes de resistencia antimicrobiana, se destaca la producción de betalactamasas y mutaciones asociadas a la resistencia a quinolonas. Además, se observaron aislamientos de un mismo patotipo agrupados en distintos filogrupos. El análisis de genómica comparativa mostró un mayor número de genes ortólogos en aislamientos que pertenecían al mismo patotipo y filogrupo. Sobre la base de lo estudiado, los aislamientos de DEC en Lima, Perú, presentan resistencia a múltiples fármacos, y se detectaron varios patotipos y filogrupos con diversidad molecular y filogenética.

Phylogenetic structure of Salmonella Enteritidis provides context for a foodborne outbreak in Peru.

Salmonella Enteritidis, an important foodborne zoonosis, has a dramatically increased number of cases around the world. To explore the phylogenetic structure of Peruvian Salmonella Enteritidis strains and their relationship with an outbreak occurred in 2018, we analyzed a comprehensive strains of S. Enteritidis received by the National Institute of Health during the period 2000-2018. A total of 180 strains were characterized by microbiological procedures, serotyping and whole genome sequencing. Based on genome sequences annotated, virulence factors and accessory genes were identified. Phylogenetic and population structure analysis were also analyzed based on SNPs. The phylogenetic analysis grouped the genomes into two well-supported clades that were consistent with population structure analysis. The clinical and food strains corresponding to the outbreak were included in the same cluster, which presented the sdhA gene, related to the increase of the virulence of this pathogen. The phylogenetic relationship of Peruvian S. Enteritidis suggests the presence of four S. enteritidis population with high epidemiological importance.

Influence of salinity on the degradation of xenobiotic compounds in rhizospheric mangrove soil.

Mangroves are highly productive tropical ecosystems influenced by seasonal and daily salinity changes, often exposed to sewage contamination, oil spills and heavy metals, among others. There is limited knowledge of the influence of salinity on the ability of microorganisms to degrade xenobiotic compounds. The aim of this study were to determine the salinity influence on the degradation of xenobiotic compounds in a semi-arid mangrove in La Guajira-Colombia and establish the more abundant genes and degradation pathways. In this study, rhizospheric soil of Avicennia germinans was collected in three points with contrasting salinity (4H, 2 M and 3 L). Total DNA extraction was performed and shotgun sequenced using the Illumina HiSeq technology. We annotated 507,343 reads associated with 21 pathways and detected 193 genes associated with the degradation of xenobiotics using orthologous genes from the KEGG Orthology (KO) database, of which 16 pathways and 113 genes were influenced by salinity. The highest abundances were found in high salinity. The degradation of benzoate showed the highest abundance, followed by the metabolism of the drugs and the degradation of chloroalkane and chloroalkene. The majority of genes were associated with phase I degradation of xenobiotics. The most abundant genes were acetyl-CoA C-acetyltransferase (atoB), catalase-peroxidase (katG) and GMP synthase (glutamine-hydrolysing) (guaA). In conclusion, the metagenomic analysis detected all the degradation pathways of xenobiotics of KEGG and 59% of the genes associated with these pathways were influenced by salinity.

[Multidrug resistance of Salmonella infantis in Peru: a study through next generation sequencing]. / Multidrogorresistencia de Salmonella infantis en Perú: un estudio mediante secuenciamiento de nueva generación.

OBJECTIVES.: To describe the phenotypic and genotypic patterns of the antimicrobial resistance of Salmonella Infantis in Peru. MATERIALS AND METHODS.: Two hundred and ninety-seven strains of Salmonella sp. submitted to the National Institute of Health (INS, in Spanish) during 2014-2016 were analyzed. The strains were phenotypically characterized by microbiological, serological, and antimicrobial susceptibility tests. Based on antimicrobial resistance patterns, 46 strains were selected and genetically characterized by next generation sequencing. RESULTS.: 193/297 (65%) strains of Salmonella Infantis were identified, of which 143 (74.1%) were multidrug-resistant producers of extended spectrum beta-lactamases (ESBL). The genomic sequencing evidenced a new profile for Salmonella Infantis; additionally, it identified the presence of 15 different genetic determinants of antimicrobial resistance coded in bacterial chromosome and five coded in a megaplasmid. The phenotypic and genotypic resistance patterns matched, with the exception of ceftazidime. Moreover, the 46 strains presented resistance and/or decreased sensitivity to quinolones. CONCLUSIONS.: Salmonella Infantis has become one of the sero-varieties most frequently referred to the INS, which includes ESBLproducing multidrug-resistant strains with resistance to quinolones. Finally, the relevance of next generation sequencing is reasserted in the characterization of new variants of pathogens that are important for public health, and their potential use in antimicrobial resistance surveillance systems.

OBJETIVOS.: Describir los patrones fenotípicos y genotípicos de la resistencia antimicrobiana de Salmonella Infantis en Perú. MATERIALES Y MÉTODOS.: Se analizaron 297 cepas de Salmonella sp. remitidas al Instituto Nacional de Salud (INS) en el periodo 2014-2016. Las cepas fueron caracterizadas fenotípicamente mediante pruebas microbiológicas, serológicas y de susceptibilidad antimicrobiana. En base a los patrones de resistencia antimicrobiana se seleccionaron 46 cepas que fueron caracterizadas genéticamente mediante secuenciamiento de nueva generación. RESULTADOS.: Se identificaron 193/297 (65,0%) cepas de Salmonella Infantis, de la cuales 143 (74,1%) fueron multidrogorresistentes productoras de betalactamasas de espectro extendido (BLEE). Con el secuenciamiento genómico se evidenció un nuevo perfil para Salmonella Infantis, además, se identificó la presencia de 15 diferentes determinantes genéticos de resistencia a los antimicrobianos codificados en cromosoma bacteriano y cinco codificados en un megaplásmido. Los patrones de resistencia fenotípicos y genotípicos coincidieron, a excepción de la ceftazidima. Asimismo, las 46 cepas presentaron resistencia y/o sensibilidad disminuida a las quinolonas. CONCLUSIONES.: Salmonella Infantis se ha convertido en una de las serovariedades más frecuentemente referidas al INS, la cual incluye cepas multidrogoresistentes productoras de BLEE con resistencia a las quinolonas. Finalmente, se reafirma la relevancia del secuenciamiento de nueva generación en la caracterización de nuevas variantes de patógenos de importancia para la salud pública y su uso potencial en los sistemas de vigilancia de resistencia antimicrobiana.

Primer aislamiento y caracterización de la cepa prototipo del virus SARS-CoV-2 a inicios de la pandemia de la COVID-19 en el Perú

Introducción: Actualmente los contagios por el virus del SARS-CoV-2 supera los 600 millones de casos en el mundo. Objetivo: Aislar y caracterizar el virus SARS-CoV-2 causante de la COVID-19 a inicios de la pandemia en el Perú. Materiales y métodos: Se realizó el aislamiento viral a partir de 20 muestras de hisopado nasal y faríngeo positivas a SARS-CoV-2 por RT-PCR. El aislamiento se realizó en las líneas celulares Vero ATCC CCL-81 y Vero E6, evaluando el efecto citopático, la presencia del virus por RT-PCR, inmunofluorescencia indirecta (IFI) y posterior identificación por secuenciación genómica. Posteriormente, uno de los aislamientos de mayor circulación fue seleccionado y denominado cepa prototipo (PE/B.1.1/28549/2020), realizándose 10 pasajes sucesivos en células Vero ATCC CCL-81 para evaluar la dinámica de mutaciones. Resultados: Se observaron 11 aislamientos de virus por efecto citopático confirmándose por RT-PCR e IFI, de los cuales 6 fueron secuenciados identificándose los linajes B.1, B.1.1, B.1.1.1 y B.1.205, según el comité Pango de los genomas. La cepa prototipo corresponde a la variante B.1.1 y el análisis de las secuencias de los pasajes sucesivos mostró mutaciones a nivel de la proteína de la espiga (S) del virus, sin variación en la identidad del linaje. Conclusiones: Se aislaron 4 linajes en la línea celular Vero ATCC CCL-81. Los subcultivos en la misma línea celular muestran mutaciones en la proteína de la espiga, lo que indica mayor adaptabilidad a la célula hospedera y variación de la patogenicidad in vitro, comportamiento que le permite tener más éxito de supervivencia.

Introduction: Currently, infections caused by the SARS-CoV-2 virus exceed 600 million cases in the world. Objective: Isolation and characterization of the SARS-CoV-2 virus causing COVID-19 at the beginning of the pandemic in Peru. Materials and methods: Twenty nasal and pharyngeal swab samples were isolated from SARS-CoV-2 using two cell lines, Vero ATCC CCL-81 and Vero E-6; virus identification was performed by RT-PCR and the onset of cytopathic effect (CPE) was evaluated by indirect immunofluorescence and subsequent identification by genomic sequencing. One of the most widely circulating isolates were selected and named the prototype strain (PE/B.1.1/28549/2020). Then 10 successive passages were performed on Vero ATCC CCL-81 cells to assess mutation dynamics. Results: We detected 11 virus isolates by cytopathic effect, and subsequently confirmed by RT-PCR and indirect immunofluorescence. Of these, six were sequenced and identified as the lineages B.1, B.1.1, B.1.1.1, and B.1.205 according to the Pango lineage nomenclature. The prototype strain corresponded to lineage B.1.1. The analysis of the strains from the successive passages showed mutations mainly at in the spike (S) protein of the virus without variation in the identity of the lineage. Conclusions: Four lineages were isolated in the Vero ATCC CCL-81 cell line. Subcultures in the same cell line show mutations in the spike protein indicating greater adaptability to the host cell and variation in pathogenicity in vitro, a behavior that allows it to have more survival success.

Diversidad molecular de variantes patogénicas de Vibrio parahaemolyticus en el Perú / Molecular diversity in pathogenic variants of vibrio parahaemolyticus in Peru

RESUMEN Con el objetivo de determinar la diversidad de variantes patogénicas de Vibrio parahaemolyticus en el Perú durante el periodo 1995-2017, se analizaron 102 genomas peruanos (97 clínicos y 5 ambientales) empleando el esquema de tipificación multilocus y BLASTn para la búsqueda de genes de virulencia. Se identificaron 15 tipos de secuencia diferentes, encontrándose que el genotipo ST3, perteneciente al clon pandémico, fue el más abundante, con 52% (n=53); seguido por el ST120, con 23,5% (n=24); y el complejo clonal CC345, con 11,8% (n=12). Un total de 89 cepas analizadas presentaron genes que codifican la isla de patogenicidad VpaI-7 (87,3%), mientras que 96 presentaron el gen tdh (94,1%), y 6, el trh (5,9%). Durante el periodo evaluado, se resalta la predominancia del ST3, causante de un importante brote en el pasado del Perú, además de otros genotipos patógenos que representan un riesgo latente en salud pública asociado al consumo de alimentos marinos.

ABSTRACT During the period from 1995 to 2017, in order to determine the diversity of Vibrio parahaemolyticus pathogenic variants in Peru, 102 Peruvian genomes (97 from a hospital setting and 5 from an out-of-hospital setting) were analyzed using the multilocus typification scheme and BLASTn in the search for virulence genes. Fifteen different sequence types were identified. It was found that the ST3 genotype, which is found in the pandemic clone, was the most abundant, with 52% (n=53); followed by ST120, with 23.5% (n=24); and the CC345 clonal complex, with 11.8% (n=12). A total of 89 analyzed strains presented genes encoding the pathogenicity island VpaI-7 (87.3%), while 96 presented the tdh gene (94.1%), and 6 the trh gene (5.9%). The ST3 genotype was the predominant one during the evaluated period, this genotype was the cause of a major outbreak in Peru's past history. Other pathogenic genotypes found represent a latent public health risk associated with seafood consumption.