RESUMEN

OBJECTIVES: To describe at genomic level nine carbapenemase-producing Klebsiella pneumoniae ST307 (Kp-ST307) clinical isolates recovered in Buenos Aires during 2017 to 2021, investigating their resistome, virulome, and phylogeny. METHODS: Antimicrobial susceptibility was determined according to Clinical and Laboratory Standards Intitute (CLSI). Genomic DNA was sequenced by Illumina MiSeq and analysed using SPAdes, PROKKA, and Kleborate. Phylogeny of 355 randomly selected Kp-ST307 genomes and those from nine local isolates was inferred by a maximum-likelihood approach. The tree was visualized using Microreact. RESULTS: Besides resistance to ß-lactams and fluoroquinolones, six out of nine Kp-ST307 were also resistant to ceftazidime/avibactam (CZA). This difficult-to-treat resvistance phenotype was mediated by blaSHV-28 and GyrA-83I/ParC-80I mutations in addition to carbapenemase coding genes. Among CZA susceptible isolates, two of them harboured blaKPC-3 while the other harboured blaKPC-2+blaCTX-M-15. Regarding CZA-resistant isolates, three harboured blaKPC-3+blaNDM-1+blaCMY-6, two carried blaKPC-2+blaNDM-5+blaCTX-M-15, and blaNDM-5+blaCTX-M-15 were detected in the remaining isolate. Furthermore, five colistin-resistant isolates presented a nonsense mutation in mgrB. Global Kp-ST307 isolates were distributed in two deep-branching lineages while local isolates were set in the main clade of the phylogenetic tree. The five isolates from the same hospital, harbouring blaKPC-3 or blaKPC-3+blaNDM-1+blaCMY-6, clustered in a monophyletic subclade with Italian isolates. Also, an isolate harbouring blaKPC-2+blaNDM-5+blaCTX-M-15 recovered in another hospital was closed to this group. The remaining local Kp-ST307 were grouped in other subclades containing isolates of diverse geographical origin. CONCLUSION: The inferred resistome was consistent with the resistant phenotype. Phylogeny suggested multiple introduction events in our region and a single major introduction in one hospital followed by local spread.

Asunto(s)

Antibacterianos , Proteínas Bacterianas , Ceftazidima , Infecciones por Klebsiella , Klebsiella pneumoniae , Pruebas de Sensibilidad Microbiana , Filogenia , beta-Lactamasas , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/efectos de los fármacos , Klebsiella pneumoniae/aislamiento & purificación , Klebsiella pneumoniae/enzimología , Klebsiella pneumoniae/clasificación , Argentina , beta-Lactamasas/genética , Proteínas Bacterianas/genética , Humanos , Infecciones por Klebsiella/microbiología , Antibacterianos/farmacología , Ceftazidima/farmacología , Farmacorresistencia Bacteriana Múltiple/genética , Genoma Bacteriano , Compuestos de Azabiciclo/farmacología , Combinación de Medicamentos , Genómica , Secuenciación Completa del Genoma

RESUMEN

Abstract Clostridioides difficile is a spore-forming anaerobe microorganism associated to nosocomial diarrhea. Its virulence is mainly associated with TcdA and TcdB toxins, encoded by their respective tcdA and tcdB genes. These genes are part of the pathogenicity locus (PaLoc). Our aim was to characterize relevant C. difficile toxinotypes circulating in the hospital setting. The tcdA and tcdB genes were amplified and digested with different restriction enzymes: EcoRI for tcdA; HincII and AccI for tcdB. In addition, the presence of the cdtB (binary toxin) gene, TcdA and TcdB toxins by dot blot and the cytotoxic effect of culture supernatants on Vero cells, were evaluated. Altogether, these studies revealed three different circulating toxinotypes according to Rupnik's classification: 0, I and VIII, being the latter the most prevalent one. Even though more studies are certainly necessary (e.g. sequencing analysis), it is worth noting that the occurrence of toxinotype I could be related to the introduction of bacteria from different geographical origins. The multivariate analysis conducted on the laboratory values of individuals infected with the most prevalent toxinotype (VIII) showed that the isolates associated with fatal outcomes (GCD13, GCD14 and GCD22) are located in regions of the biplots related to altered laboratory values at admission. In other patients, although laboratory values at admission were not correlated, levels of urea, creatinine and white blood cells were positively correlated after the infection was diagnosed. Our study reveals the circulation of different toxinotypes of C. difficile strains in this public hospital. The variety of toxinotypes can arise from pre-existing microorganisms as well as through the introduction of bacteria from other geographical regions. The existence of microorganisms with different pathogenic potential is relevant for the control, follow-up, and treatment of the infections.

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Resumen Clostridioides difficile es un anaerobio esporulado que se asocia con episodios de diarreas hospitalarias. Su virulencia se encuentra vinculada, principalmente, a las toxinas TcdA y TcdB, codificadas por sus respectivos genes, tcdA y tcdB, que son parte de un locus de patogenicidad (PaLoc). Nuestro objetivo fue caracterizar los toxinotipos de C. difficile circulantes en un hospital público. Los genes tcdA y tcdB fueron amplificados y digeridos con diferentes enzimas de restricción: EcoRI para tcdA; HincII y AccI para tcdB. Además, se evaluó la presencia de cdtB (gen de la toxina binaria B) y de las toxinas A y B (por dot blot), así como el efecto citotóxico de sobrenadantes de cultivo sobre células Vero. En conjunto, estos estudios revelaron tres toxinotipos circulantes según la clasificación de Rupnik: 0, I y VIII; el más prevalente fue el último. Aunque son necesarios más estudios (ej., secuenciación), es interesante notar que la presencia del toxinotipo I podría estar relacionada con la introducción de bacterias de diferente origen geográfico. En los pacientes infectados con el toxinotipo VIII, el análisis multivariante de los resultados de laboratorio mostró que los aislamientos asociados a decesos (GCD13, GCD14 y GCD22) estaban situados en regiones de los biplots relacionados con valores de laboratorio alterados al momento de la internación. En los otros pacientes, aunque no se observó correlación entre los valores de laboratorio al momento de la internación y la evolución clínica, los niveles de urea, creatinina y recuento de glóbulos blancos estuvieron correlacionados positivamente entre sí una vez diagnosticada la infección. Nuestro estudio revela la circulación de diferentes toxinotipos de C. difficile en un mismo hospital público. La variedad de toxinotipos puede originarse a partir de microorganismos preexistentes en la región, así como también por la introducción de bacterias provenientes de otras regiones geográficas. La existencia de microorganismos con diferente potencial patogénico es relevante para el control, el seguimiento y el tratamiento de las infecciones.

RESUMEN

Clostridioides difficile is a spore-forming anaerobe microorganism associated to nosocomial diarrhea. Its virulence is mainly associated with TcdA and TcdB toxins, encoded by their respective tcdA and tcdB genes. These genes are part of the pathogenicity locus (PaLoc). Our aim was to characterize relevant C. difficile toxinotypes circulating in the hospital setting. The tcdA and tcdB genes were amplified and digested with different restriction enzymes: EcoRI for tcdA; HincII and AccI for tcdB. In addition, the presence of the cdtB (binary toxin) gene, TcdA and TcdB toxins by dot blot and the cytotoxic effect of culture supernatants on Vero cells, were evaluated. Altogether, these studies revealed three different circulating toxinotypes according to Rupnik's classification: 0, I and VIII, being the latter the most prevalent one. Even though more studies are certainly necessary (e.g. sequencing analysis), it is worth noting that the occurrence of toxinotype I could be related to the introduction of bacteria from different geographical origins. The multivariate analysis conducted on the laboratory values of individuals infected with the most prevalent toxinotype (VIII) showed that the isolates associated with fatal outcomes (GCD13, GCD14 and GCD22) are located in regions of the biplots related to altered laboratory values at admission. In other patients, although laboratory values at admission were not correlated, levels of urea, creatinine and white blood cells were positively correlated after the infection was diagnosed. Our study reveals the circulation of different toxinotypes of C. difficile strains in this public hospital. The variety of toxinotypes can arise from pre-existing microorganisms as well as through the introduction of bacteria from other geographical regions. The existence of microorganisms with different pathogenic potential is relevant for the control, follow-up, and treatment of the infections.

Asunto(s)

Toxinas Bacterianas , Clostridioides difficile , Animales , Chlorocebus aethiops , Humanos , Toxinas Bacterianas/genética , Toxinas Bacterianas/análisis , Enterotoxinas/genética , Clostridioides difficile/genética , Clostridioides , Células Vero , Hospitales Públicos , Proteínas Bacterianas/genética

RESUMEN

Abstract MDR Klebsiella pneumoniae ST307 is a high-risk clone, whose genetic features contribute to its adaptation to hospital environments and the human host. This study describesthe emergence and clonal dissemination of K. pneumoniae ST307, recovered during November2018 to February 2019 in a hospital in Buenos Aires city, which concurrently harbored KPC-3and NDM-1. These isolates were resistant to all -lactams and to the ceftazidime/avibactamcombination. Molecular studies showed that blaKPC-3was located in Tn4401a platform, whileblaNDM-1was surrounded upstream by ISKpn14 followed by a partial sequence of ISAba125 anddownstream by bleMBL-trpF, located in a 145.5 kb conjugative plasmid belonging to the Inc A/Cgroup. The dissemination of K. pneumoniae ST307 isolates co-producing KPC-3 and NDM-1 couldlead to a worrisome scenario due to the remarkable features of this clone and its resistanceprofile.

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Resumen Klebsiella pneumoniae ST307 es un clon de alto riesgo, cuyas características genéticas contribuyen a su adaptación al entorno hospitalario y al huésped humano. Este estudio describe la emergencia y diseminación clonal de aislamientos de K. pneumoniae ST307 productores de KPC-3 y NDM-1, recuperados en un hospital de Buenos Aires. Estos aislamientos fueron resistentes a todos los p-lactámicos y a la combinación ceftacidima/avibactam. Los estudios moleculares evidenciaron que el contexto genético de blaKPC-3 se correspondió con el Tn4401a, mientras que blaNDM-1 estuvo flanqueado corriente arriba por ISKpn14 y una secuencia parcial de ISAba125 y corriente abajo por bleMBL - trpF, localizado a su vez en un plásmido conjugativo de 145.5 kb perteneciente al grupo Inc A/C. La emergencia de aislamientos de K. pneumoniae ST307 coproductores de KPC-3 y NDM-1 pone de manifiesto una situación altamente preocupante debido a las características de este clon y a su perfil de multirresistencia.

RESUMEN

MDR Klebsiella pneumoniae ST307 is a high-risk clone, whose genetic features contribute to its adaptation to hospital environments and the human host. This study describes the emergence and clonal dissemination of K. pneumoniae ST307, recovered during November 2018 to February 2019 in a hospital in Buenos Aires city, which concurrently harbored KPC-3 and NDM-1. These isolates were resistant to all ß-lactams and to the ceftazidime/avibactam combination. Molecular studies showed that blaKPC-3 was located in Tn4401a platform, while blaNDM-1 was surrounded upstream by ISKpn14 followed by a partial sequence of ISAba125 and downstream by bleMBL-trpF, located in a 145.5kb conjugative plasmid belonging to the Inc A/C group. The dissemination of K. pneumoniae ST307 isolates co-producing KPC-3 and NDM-1 could lead to a worrisome scenario due to the remarkable features of this clone and its resistance profile.

Asunto(s)

Infecciones por Klebsiella , Klebsiella pneumoniae , Humanos , Klebsiella pneumoniae/genética , beta-Lactamasas/genética , Antibacterianos , Pruebas de Sensibilidad Microbiana , Proteínas Bacterianas/genética

RESUMEN

OBJECTIVES: To assess the epidemiological features of 76 Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella pneumoniae (KPC-Kp) isolates recovered from three hospitals in Buenos Aires, Argentina, during 2015-2017. METHODS: Antimicrobial susceptibilities were determined according to CLSI Clinical and Laboratoy Standards guidelines. Molecular typing of KPC-Kp was performed by pulsed-field gel electrophoresis (PFGE)-Xbal and multilocus sequence typing. Plasmid encoded genes involved in carbapenem, fosfomycin and colistin resistance were detected by polymerase chain reaction (PCR) and sequencing. Also, mgrB inactivation was investigated in those colistin-resistant isolates. Genetic platforms involved in horizontal spread of blaKPC were investigated by PCR mapping. RESULTS: Besides ß-lactams, high resistance rates were observed for gentamycin, quinolones and trimethoprim-sulfamethoxazole. KPC-Kp sequence type (ST)258 corresponded to 26% of the isolates, while 42% corresponded to ST25. The other isolates were distributed in a diversity of lineages such as ST11 (10.5%), ST392 (10.5%), ST307, ST13, ST101, ST15 and ST551. blaKPC-2 was detected in 75 of 76 isolates, and one ST307 isolate harboured blaKPC-3. Tn4401 was identified as the genetic platform for blaKPC in epidemic lineages such as ST258 and ST307. However, in ST25 and ST392, which are usually not related to blaKPC, a blaKPC-bearing non-Tn4401 element was identified. Alterations in mgrB were detected in seven of 11 colistin-resistant isolates. CONCLUSIONS: Despite previous reports in Argentina, ST258 is no longer the absolute clone among KPC-Kp isolates. In the present study, dissemination of more virulent lineages such as the hypermucoviscous ST25 was detected. The emergence of the high-risk clone ST307 and occurrence of blaKPC-3 was noticed for the first time in this region.

Asunto(s)

Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Infecciones por Klebsiella/microbiología , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/metabolismo , Epidemiología Molecular , beta-Lactamasas/genética , beta-Lactamasas/metabolismo , Argentina/epidemiología , Técnicas de Tipificación Bacteriana , Carbapenémicos , Colistina/farmacología , Farmacorresistencia Bacteriana Múltiple/genética , Electroforesis en Gel de Campo Pulsado , Humanos , Infecciones por Klebsiella/epidemiología , Klebsiella pneumoniae/efectos de los fármacos , Klebsiella pneumoniae/aislamiento & purificación , Pruebas de Sensibilidad Microbiana , Tipificación Molecular , Tipificación de Secuencias Multilocus , Plásmidos , beta-Lactamas

RESUMEN

Ten IMP-8-producing Escherichia coli isolates were recovered from surveillance cultures of a neonatal intensive care unit; eight of the isolates were clonally related. A 168.2-kb blaIMP-8 plasmid was fully sequenced, and it corresponded to the recently described IncA/C1-ST13 plasmid. This plasmid was detected in all isolates, even in those that were not clonally related. One unrelated isolate was also resistant to colistin and positive for mcr-1 This marker was located in a 62.7-kb IncI2 plasmid, which was also fully sequenced.

Asunto(s)

Proteínas de Escherichia coli/genética , Escherichia coli/genética , Plásmidos/genética , beta-Lactamasas/metabolismo , Antibacterianos/farmacología , Colistina/farmacología , Farmacorresistencia Bacteriana/genética , Escherichia coli/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , beta-Lactamasas/genética

Asunto(s)

Proteínas Bacterianas/biosíntesis , Genes Bacterianos , Klebsiella pneumoniae/enzimología , beta-Lactamasas/biosíntesis , Antibacterianos/farmacología , Argentina/epidemiología , Hospitales , Humanos , Infecciones por Klebsiella/epidemiología , Infecciones por Klebsiella/microbiología , Infecciones por Klebsiella/prevención & control , Klebsiella pneumoniae/efectos de los fármacos , Klebsiella pneumoniae/genética , Pruebas de Sensibilidad Microbiana

RESUMEN

El objetivo de éste estudio es aportar información sobre los genotipos de Chlamydia trachomatis (Ct) que circulan en el área metropolitana de Buenos Aires y su Conurbano. Se estudiaron 38 muestras positivas para Ct, provenientes de distintos hospitales, obtenidas del tracto urogenital de mujeres y hombres, y de conjuntivas de neonatos. La confirmación de la presencia de Ct se realizó por amplificación génica de un segmento del plásmido críptico mediante PCR. Para la genotipificación de Ct se amplificó el gen omp-1, los productos de ésta amplificación fueron digeridos con el enzima AluI, y los fragmentos obtenidos fueron separados por electroforesis en geles de poliacrilamida al 13,5 por ciento. Los resultados obtenidos fueron confirmados por digestión con EcoRI. Cuando fue necesario se recurrió a la digestión con una segunda enzima. El genotipo E, detectado en 20 casos, fue el más frecuente y estuvo presente en muestras de origen cervical, uretral y conjuntival, lo que en distribución muestra un perfil similar a la mayoría de las regiones donde se han estudiado. Esta mayor frecuencia de detección podría deberse a una mejor adaptación de éste genotipo a las condiciones de transmisión e infección y a las islas de virulencia particulares del genotipo (AU)

Asunto(s)

Humanos , Recién Nacido , Masculino , Femenino , Chlamydia trachomatis/clasificación , Argentina , Chlamydia trachomatis/aislamiento & purificación , Reacción en Cadena de la Polimerasa , Técnicas de Tipificación Bacteriana , América Latina , Infecciones por Chlamydia/diagnóstico

RESUMEN

El objetivo de éste estudio es aportar información sobre los genotipos de Chlamydia trachomatis (Ct) que circulan en el área metropolitana de Buenos Aires y su Conurbano. Se estudiaron 38 muestras positivas para Ct, provenientes de distintos hospitales, obtenidas del tracto urogenital de mujeres y hombres, y de conjuntivas de neonatos. La confirmación de la presencia de Ct se realizó por amplificación génica de un segmento del plásmido críptico mediante PCR. Para la genotipificación de Ct se amplificó el gen omp-1, los productos de ésta amplificación fueron digeridos con el enzima AluI, y los fragmentos obtenidos fueron separados por electroforesis en geles de poliacrilamida al 13,5 por ciento. Los resultados obtenidos fueron confirmados por digestión con EcoRI. Cuando fue necesario se recurrió a la digestión con una segunda enzima. El genotipo E, detectado en 20 casos, fue el más frecuente y estuvo presente en muestras de origen cervical, uretral y conjuntival, lo que en distribución muestra un perfil similar a la mayoría de las regiones donde se han estudiado. Esta mayor frecuencia de detección podría deberse a una mejor adaptación de éste genotipo a las condiciones de transmisión e infección y a las islas de virulencia particulares del genotipo

Asunto(s)

Humanos , Recién Nacido , Masculino , Femenino , Chlamydia trachomatis , Argentina , Técnicas de Tipificación Bacteriana , Infecciones por Chlamydia , Chlamydia trachomatis , América Latina , Reacción en Cadena de la Polimerasa