Actinomyces europaeus (Gleimia europaea) asociado con absceso cerebral: comunicación de tres casos / Actinomyces europaeus (Gleimia europaea) associated with brain abscess: A reportof three cases

Resumen El absceso cerebral es una infección focal caracterizada por acumulación de pus enel parénquima cerebral; su diagnóstico es de urgencia debido a la alta mortalidad que acarrea.Presentamos tres casos de pacientes con abscesos cerebrales con foco otogénico de origen poli-microbiano, que presentaron en común el aislamiento de Actinomyces europaeus, agente nodescrito hasta el momento en esta localización. A. europaeus fue identificado por la metodo-logía convencional, por espectrometría de masas por desorción/ionización asistida por matriz(MALDI-TOF MS) y por secuenciación del gen ARNr 16S. La sensibilidad antibiótica se evaluó porel método epsilométrico. Todos los aislados presentaron sensibilidad a penicilina, vancomicinay linezolid, mientras que la sensibilidad a clindamicina y eritromicina fue variable. La iden-tificación por MALDI-TOF MS permitió arribar a nivel de especie de forma rápida y confiabley dar una respuesta oportuna y efectiva, evitando el retraso en el tratamiento, lo que sueleincrementar la morbimortalidad del cuadro clínico.

Corynebacterium guaraldiae sp. nov.: a new species of Corynebacterium from human infections.

Non-diphtheria Corynebacterium species (NDC) belonging to the human skin and mucosa microbiota are frequently neglected as contaminants. However, reports of human infections by Corynebacterium spp. have increased considerably in recent years. In this study, a group of six NDC isolates of urine (n = 5) and sebaceous cyst (n = 1) from two South American countries were identified at genus level or misidentified based on API® Coryne and genetic/molecular analyses. The 16S rRNA (99.09-99.56%) and rpoB (96.18-97.14%) gene sequence similarities of the isolates were higher when compared with Corynebacterium aurimucosum DSM 44532 T. Multilocus sequence analysis (MLSA) indicated that these six NDC isolates compose a distinctive phylogenetic clade. Genome-based taxonomic analysis with the whole-genome sequences was able to separate these six isolates from other known Corynebacterium type strains. Average nucleotide identity (ANI), average amino acid identity (AAI), and digital DNA-DNA hybridization (dDDH) values between closely related type strains and the six isolates were considerably lower than the currently recommended threshold values for species circumscription. Phylogenetic and genomic taxonomy analyses indicated these microorganisms as a novel Corynebacterium species, for which we formally propose the name Corynebacterium guaraldiae sp. nov. with isolate 13T (= CBAS 827T = CCBH 35012T) as type strain.

Infección de piel y partes blandas por Vibrio vulnificus. Comunicación de un caso diagnosticado en Argentina / Vibrio vulnificus infection of the skin and soft parts. Communication of a case diagnosed in Argentina

Resumen Vibrio vulnificus es una de las especies de Vibrio más virulentas que se conocen. Es una bacteria de distribución universal. El primer caso registrado en Uruguay se produjo en 2001, y desde entonces ocurren varias infecciones por año. Recientemente, en ese país, V. vulnificus fue responsable de una infección de partes blandas de curso letal. Aunque no han sido comunicados casos de infección humana por esta especie en Argentina, se ha identificado recientemente Vibrio vulnificus en muestras asociadas con microplancton en el estuario del Río Negro. Presentamos el caso de una infección grave de piel y partes blandas por V. vulnificus a partir de una herida abierta en un paciente en contacto con medio acuático marino en la costa de Uruguay del Río de la Plata. El aislamiento de vibrios en muestras de heridas puede causar un daño en los tejidos con rápida progresión, en particular V. vulnificus, que tiene una alta mortalidad sin la precoz y apropiada intervención. En nuestro caso, la rápida identificación del microorganismo permitió avalar el tratamiento empírico utilizado, con una buena evolución clínica.

Abstract Vibrio vulnificus is one of the most virulent Vibrio species known. It is a bacterium with universal distribution. The first case registered in Uruguay occurred in 2001 and, since then, several infections have occurred per year. Recently, in this country, V. vulnificus was responsible for a fatal soft tissue infection. Although no cases of human infection with this species have been reported in Argentina, researchers have recently identified V. vulnificus in samples associated with microplankton in the Rio Negro estuary. We present the case of a severe skin and soft tissue infection by V. vulnificus from an open wound in a patient in contact with a marine aquatic environment on the coast of the River Plate, in Uruguay. Isolation of vibrios from wound specimens can cause rapidly progressing tissue damage, particularly V. vulnificus which has a high mortality rate without early and appropriate intervention. In our case, the rapid identification of the microorganism allowed us to support the empirical treatment used, which a good clinical evolution.

Descripción de un caso de sepsis abdominal por Desulfovibrio desulfuricans / Description of a case of abdominal sepsis due to Desulfovibrio desulfuricans

Resumen Desulfovibrio spp. son bacterias anaerobias estrictas, ubicuas en la naturaleza, quepueden formar parte del tracto gastrointestinal humano o animal, pero también son bacteriasambientales presentes en el suelo y en el agua. Pueden persistir de manera asintomática enel intestino o comportarse como patógenos oportunistas, asociados con bacteriemia primariae infecciones intraabdominales. El número de infecciones por Desulfovibrio spp. puede estarsubestimado debido a su lenta velocidad de crecimiento y a que muchos laboratorios no realizancultivos en anaerobiosis de manera rutinaria. Pruebas sencillas, como el examen de la movilidaden fresco y de la morfología celular en la coloración de Gram, sumadas a la presencia de SH2en agar SIM y a la observación de una fluorescencia roja a pH alcalino bajo luz UV, seríanindicativas de Desulfovibrio spp. Se describe el caso de una bacteriemia por Desulfovibriodesulfuricans en una mujer con cuadro clínico de sepsis abdominal por apendicitis gangrenosacon fallo multiorgánico.

Abstract Desulfovibrio spp. are strict anaerobes that are ubiquitous in nature. They can reside in the human or animal gastrointestinal tract and, as they are also environmental bacteria, may be present in soil and water. They can persist asymptomatically in the intestine or behave as opportunistic pathogens associated with primary bacteremia and intraabdominal infections. Several Desulfovibrio spp. infections may be underestimated due to their slow growth rate and because many laboratories do not routinely perform anaerobic cultures. Simple tests such as motility detection on a fresh subculture, Gram stain to confirm cell morphology, presence of H2S in SIM agar and production of a red fluorescence in alkaline pH under UV light would be indicative of Desulfovibrio spp.

Dolosigranulum pigrum en absceso corneal / Dolosigranulum pigrum in corneal abscess

Resumen Dolosigranulum pigrum es un coco gram positivo, anaerobio facultativo, que forma parte de la microbiota oral y del tracto respiratorio superior. Aunque los reportes de infecciones por este microorganismo son escasos, se lo ha asociado a un amplio espectro de enfermedades infecciosas. Se describe el caso de un hombre adulto con un absceso corneal del que se aisló D. pigrum. El microorganismo fue identificado por espectrometría de masas (MALDI-TOF MS) y secuenciación del gen 16S ARNr. A su vez, se logró la identificación presuntiva mediante pruebas fenotípicas claves, como la disposición en racimos en la coloración de Gram, la prueba negativa de la catalasa, la producción de pirrolidonil arilamidasa y leucina aminopeptidasa, el crecimiento en NaCl al 6,5% y la hidrólisis de esculina. Los datos de la literatura y el presente caso respaldan la asociación del microorganismo con infecciones oculares, a menudo de curso destructivo, principalmente en pacientes de edad avanzada.

Abstract Dolosigranulum pigrum is a gram-positive, facultatively anaerobic coccus, which is part of the oral and upper respiratory tract microbiota. Although reports of infections by this microorganism are scarce, it has been associated with a wide spectrum of infectious diseases. The case of an elderly man with a lower corneal abscess, in which Dolosigranulum pigrum was isolated, is described. The microorganism was identified by mass spectrometry (MALDI-TOF MS) and by the sequencingof the 16S rRNAgene. Furthermore, the presumptive identification of the causative agent was achieved by using key phenotypic tests such as the cluster arrangement in Gram stain, the negative catalase test, the production of pyrrolidonyl arylamidase and leucine aminopeptidase activity, the growth in 6.5% NaCl and esculin hydrolysis. The data from the literature (and the present case) support the association of the microorganism with ocular infections, which often take a destructive course, mainly in elderly patients.

[Corynebacterium kroppenstedtii breast infections: Report of four cases]. / Infecciones mamarias por Corynebacterium kroppenstedtii: comunicación de 4 casos.

Corynebacterium kroppenstedtii is an immobile, non-sporulated, glucose-fermenting and lipophilic gram-positive rod of the skin microbiota. In recent years, numerous isolates of this species have been reported mainly in breast infections, such as abscesses and granulomatous mastitis. We present here four cases of C. kroppenstedtii infections isolated from breast aspiration samples in women. C. kroppenstedtii was identified by conventional methodology and mass spectrometry (MALDI-TOF MS). Using the epsilometric method, these isolates showed susceptibility to penicillin, ceftriaxone, minocycline, ciprofloxacin, and vancomycin, and variable susceptibility to clindamycin and trimethoprim sulfamethoxazole. Due to the association of C. kroppenstedtii with mammary infections, the identification at the species level of those corynebacteria isolated from this location is highly advisable in order to reach the final diagnosis and to test the antimicrobial susceptibility in order to apply the appropriate antibiotic treatment.

Diversity of Achromobacter species recovered from patients with cystic fibrosis, in Argentina / Diversidad de las especies de Achromobacter recuperadas de pacientes con fibrosis quística en Argentina

Abstract Different phenotype-based techniques and molecular tools were used to describe the distribution of different Achromobacter species in patients with cystic fibrosis (CF) in Argentina, and to evaluate their antibiotic resistance profile. Phenotypic identification was performed by conventional biochemical tests, commercial galleries and MALDI-TOF MS. Genetic approaches included the detection of A. xylosoxidans specific marker blaoxa-114, the amplificaron and sequencing of the 16S rRNA gene, nrdA and blaOXA complete sequence, and MLST analysis. Phenotypic approaches, even MALDI-TOF, rendered inconclusive or misleading results. On the contrary, concordant results were achieved with the nrdA sequencing or sequence type (ST) analysis, and the complete blaOXA sequencing, allowing a reliable discrimination of different Achromobacter species. A. xylosoxidans accounted for 63% of Achromobacter infections and A. ruhlandii accounted for 17%. The remaining species corresponded to A. insuavis, A. dolens, A. marplatensis and A. pulmonis. Antimicrobial susceptibilities were determined by the agar dilution method according to CLSI guidelines. Piperacillin, piperacillin/tazobactam and car-bapenems were the most active antibiotics. However, the emergence of carbapenem-resistant isolates was detected. In conclusion, prompt and accurate identification tools were necessary to determine that different Achromobacter species may colonize/infect the airways of patients with CF. Moreover, antimicrobial therapy should be administered based on the susceptibility profile of individual Achromobacter sp. isolates. © 2019 Asociación Argentina de Microbiología. Published by Elsevier España, S.L.U. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/).

Resumen Se emplearon diversas técnicas fenotípicas y moleculares para describir la distribución de diferentes especies del género Achromobacter en pacientes con fibrosis quística (FQ) en Argentina, y se evaluó el perfil de resistencia a los antibióticos. Se realizó la identificación fenotípica por pruebas bioquímicas convencionales, galerías comerciales y MALDI-TOF MS. El enfoque genético incluyó la detección del marcador especie-específico de A. xylosoxidans bla[PRESERVECIRC]tu, la amplificación y la secuenciación de los genes ARNr 16S, nrdA y secuencia completa de blaOXA, y el análisis por MLST. Los enfoques fenotípicos, incluso la técnica de MALDI-TOF, proporcionaron resultados no concluyentes o erróneos. Por el contrario, se obtuvieron resultados concordantes entre la secuenciación del gen nrdA o el análisis de secuenciotipos (ST) y la secuenciación completa de blaOXA, lo que permitió una discriminación confiable de las diferentes especies de Achromobacter. A. xylosoxidans representó el 63% de las infecciones por Achromobacter y A. ruhlandii representó el 17%. Las especies restantes correspondieron a A. insuavis, A. dolens, A. marplatensis y A. pulmonis. Se determinó la sensibilidad a antimicrobianos por el método de dilución en agar de acuerdo al CLSI. Los antibióticos más activos fueron piperacilina, piperacilina/tazobactam y carbapenemes. Sin embargo, se detectó la emergencia de aislamientos resistentes a carbapenemes. En conclusión, resultaron necesarias herramientas de identificación rápida y precisas para determinar las diferentes especies del género Achro-mobacter capaces de colonizar/infectar las vías respiratorias de los pacientes con FQ. Asimismo, la terapia antimicrobiana debería llevarse a cabo en función del perfil de sensibilidad de los aislamientos individuales de Achromobacter spp. © 2019 Asociacion Argentina de Microbiología. Publicado por Elsevier Espana, S.L.U. Este es un artículo Open Access bajo la licencia CC BY-NC-ND (https://creativecommons.org/licenses/by-nc-nd/4.0/).

Diversity of Achromobacter species recovered from patients with cystic fibrosis, in Argentina.

Different phenotype-based techniques and molecular tools were used to describe the distribution of different Achromobacter species in patients with cystic fibrosis (CF) in Argentina, and to evaluate their antibiotic resistance profile. Phenotypic identification was performed by conventional biochemical tests, commercial galleries and MALDI-TOF MS. Genetic approaches included the detection of A. xylosoxidans specific marker blaoxa-114, the amplification and sequencing of the 16S rRNA gene, nrdA and blaOXA complete sequence, and MLST analysis. Phenotypic approaches, even MALDI-TOF, rendered inconclusive or misleading results. On the contrary, concordant results were achieved with the nrdA sequencing or sequence type (ST) analysis, and the complete blaOXA sequencing, allowing a reliable discrimination of different Achromobacter species. A. xylosoxidans accounted for 63% of Achromobacter infections and A. ruhlandii accounted for 17%. The remaining species corresponded to A. insuavis, A. dolens, A. marplatensis and A. pulmonis. Antimicrobial susceptibilities were determined by the agar dilution method according to CLSI guidelines. Piperacillin, piperacillin/tazobactam and carbapenems were the most active antibiotics. However, the emergence of carbapenem-resistant isolates was detected. In conclusion, prompt and accurate identification tools were necessary to determine that different Achromobacter species may colonize/infect the airways of patients with CF. Moreover, antimicrobial therapy should be administered based on the susceptibility profile of individual Achromobacter sp. isolates.

Desarrollo y evaluación de una base de datos in house para la identificación rápida de Burkholderia contaminons por EM MALDI-TOF / Development and evaluation of an in-house database for quick identification of Burkholderia contaminans by MALDI-TOF MS

La espectrometría de masas (EM) (matrix assisted laser desorption ionization-time of flight) MALDI-TOF demostró ser una herramienta robusta para la identificación de numerosos grupos taxonómicos. No obstante, presenta limitaciones. Una ventaja clave de la técnica es la flexibilidad para la incorporación de espectros proteicos de microorganismos ausentes en la base de datos comercial. Dada la prevalencia de Burkholderia contaminans en los pacientes fibroquísticos en Argentina, y a que en ellos es crucial el diagnóstico microbiológico rápido y confiable, la EM MALDI-TOF surge como una herramienta estratégica. El objetivo del trabajo fue desarrollar una base de datos adicional con espectros peptídicos de aislamientos de referencia de B. contaminans. La misma demostró ser exitosa para la identificación del 97% de los aislamientos analizados. Por lo cual la EM MALDI-TOF con la base de datos extendida resultó ser una herramienta útil para la identificación y diferenciación de otras especies relacionadas a B. contaminans.

MALDI-TOF (matrix assisted laser desorption ionization-time of flight) mass spectrometry (MS) proved to be a robust tool for the identification of numerous taxonomic groups. However, it has limitations. A key advantage of this technique is the flexibility for the incorporation of protein profiles of microorganisms not included in the commercial database. Due to the prevalence of Burkholderia contaminans in fibrocystic patients in Argentina and the fact that rapid and reliable microbiological diagnosis is crucial in them, MALDI-TOF MS emerges as a strategic tool. The aim of this work was to develop an additional database with peptide spectra of reference isolates of B. contaminans. This database demonstrated to be successful for the identification of 97% of the isolates analyzed. Therefore, MALDI-TOF MS with the extended database was a useful tool for the identification and differentiation of other related species to B. contaminans.

[Development and evaluation of an in-house database for quick identification of Burkholderia contaminans by MALDI-TOF MS]. / Desarrollo y evaluación de una base de datos in house para la identificación rápida de Burkholderia contaminans por EM MALDI-TOF.

MALDI-TOF (matrix assisted laser desorption ionization-time of flight) mass spectrometry (MS) proved to be a robust tool for the identification of numerous taxonomic groups. However, it has limitations. A key advantage of this technique is the flexibility for the incorporation of protein profiles of microorganisms not included in the commercial database. Due to the prevalence of Burkholderia contaminans in fibrocystic patients in Argentina and the fact that rapid and reliable microbiological diagnosis is crucial in them, MALDI-TOF MS emerges as a strategic tool. The aim of this work was to develop an additional database with peptide spectra of reference isolates of B. contaminans. This database demonstrated to be successful for the identification of 97% of the isolates analyzed. Therefore, MALDI-TOF MS with the extended database was a useful tool for the identification and differentiation of other related species to B. contaminans.

Draft genome sequence of a taxonomically unique acinetobacter clinical strain with proteolytic and hemolytic activities.

Acinetobacter sp. strain A47, which has been recovered from several soft tissue samples from a patient undergoing reconstructive surgery due to a traumatic amputation, was categorized as a taxonomically unique bacterial strain. The molecular analysis based on three housekeeping protein-coding genes (16S rRNA, rpoB, and gyrB) showed that strain A47 does not belong to any of the hitherto known taxa and may represent a previously undescribed Acinetobacter species.

A taxonomically unique Acinetobacter strain with proteolytic and hemolytic activities recovered from a patient with a soft tissue injury.

A taxonomically unique bacterial strain, Acinetobacter sp. A47, has been recovered from several soft tissue samples from a patient undergoing reconstructive surgery owing to a traumatic amputation. The results of 16S rRNA, rpoB, and gyrB gene comparative sequence analyses showed that A47 does not belong to any of the hitherto-known taxa and may represent an as-yet-unknown Acinetobacter species. The recognition of this novel organism contributes to our knowledge of the taxonomic complexity underlying infections caused by Acinetobacter.

Presence of OXA-type enzymes in Achromobacter insuavis and A. dolens.

The accurate species identification of Achromobacter isolates is difficult and the clinical isolates of this genus are mostly referred as A. xylosoxidans. Here, we report new OXA variants in 2 isolates identified as A. insuavis (A114, A79) and 1 isolate identified as A. dolens (A336). These results suggest that different bla OXA genes are ubiquitous in the different species of Achromobacter spp. The role of the other species of Achromobacter in clinical samples needs to be reevaluated, and the proper identification is absolutely necessary to understand the epidemiology of this genus.

Bacteremia caused by an Acinetobacter junii strain harboring class 1 integron and diverse DNA mobile elements.

INTRODUCTION: Infections caused by Acinetobacter junii are rarely reported. However, some outbreaks of septicemia in neonates and pediatric oncology patients, as well as meningitis, peritonitis, and ocular infection have been described. Since it is highly infrequent to find the molecular characterization of A. junii strains in literature, in this study we described the molecular characterization of A. junii isolates recovered from blood samples of a renal transplant patient. METHODOLOGY: The case was defined as a catheter-related bacteremia caused by A. junii. The patient responded favorably after catheter removal and treatment with ciprofloxacin. RESULTS AND CONCLUSION: The complete molecular characterization of the isolate showed that it harbored a class 1 integron and diverse DNA mobile elements. This explains its genomic plasticity for acquiring antimicrobial resistance determinants and for adapting to a nosocomial niche.

[Bordetella holmesii endocarditis in an asplenic patient]. / Endocarditis por Bordetella holmesii en un paciente asplénico.

The case of a 52-year-old female patient with a history of critical aortic stenosis, hypothyroidism and splenectomy as treatment for her Hodgkin's lymphoma is herein presented. In April 2011, the patient was admitted to the cardiology service due to global heart failure, fever and poor response to diuretic and vasodilator therapy. A transesophageal echocardiogram showed images compatible with vegetations in the aortic, pulmonary, and mitral valves. A diagnosis of infective endocarditis was made. Growth of gram-negative coccobacilli was observed in two blood culture sets. The microorganism was finally identified as Bordetella holmesii. The patient was treated with ceftriaxone 1 g every 12 hours for 28 days with favorable outcome.

Distribution of allelic variants of the chromosomal gene bla OXA-114-like in Achromobacter xylosoxidans clinical isolates.

Achromobacter xylosoxidans is increasingly being documented in cystic fibrosis patients. The bla(OXA-114) gene has been recognized as a naturally occurring chromosomal gene, exhibiting different allelic variants. In the population under study, the bla(OXA-114)-like gene was found in 19/19 non-epidemiological-related clinical isolates of A. xylosoxidans with ten different alleles including 1 novel OXA-114 variant.

Abscesos cerebrales primarios por Nocardia farcinica en un paciente con SIDA / Primary cerebral abscesses due to Nocardia farcinica in an AIDS patient

Las bacterias del género Nocardia son microorganismos Gram positivos, aerobios, parcialmente ácido resistente, que en la mayoría de los casos se adquieren por inhalación o inoculación a través de la piel. La diseminación hemática puede comprometer el sistema nervioso central (SNC) bajo la forma de abscesos intraparenquimatosos. El compromiso del SNC también puede serprimario y afectar tanto a sujetos inmunocomprometidos como infección oportunista, como a inmunocompetentes. La frecuencia de abscesos cerebrales por Nocardia es baja y representa el 2por ciento del total de los abscesos cerebrales. El diagnóstico precoz asociado al tratamiento quirúrgico y laantibioticoterapia prolongada pueden mejorar el pronóstico y la morbimortalidad de estos pacientes.En huéspedes inmunocompetentes Nocardia spp.causan más frecuentemente actinomicetomas quenocardosis cerebral. Aquí se presenta un paciente VIH positivo que desarrolló abscesos cerebrales primarios por Nocardia farcinica y se realiza una revisión de la literatura sobre el tema.

Endocarditis por Bordetella holmesii en un paciente asplénico / [Bordetella holmesii endocarditis in an asplenic patient].

The case of a 52-year-old female patient with a history of critical aortic stenosis, hypothyroidism and splenectomy as treatment for her Hodgkin’s lymphoma is herein presented. In April 2011, the patient was admitted to the cardiology service due to global heart failure, fever and poor response to diuretic and vasodilator therapy. A transesophageal echocardiogram showed images compatible with vegetations in the aortic, pulmonary, and mitral valves. A diagnosis of infective endocarditis was made. Growth of gram-negative coccobacilli was observed in two blood culture sets. The microorganism was finally identified as Bordetella holmesii. The patient was treated with ceftriaxone 1 g every 12 hours for 28 days with favorable outcome.