[Sporotrichoid nocardiosis by Nocardia brasiliensis]. / Nocardiosis esporotricoide por Nocardia brasiliensis.

Nocardia brasiliensis is a gram-positive, branched, aerobic, acid-resistant, rod-shaped bacillus that inhabits in soil, rotten organic matter and waters. Cutaneous nocardiosis in immunocompetent individuals can manifest in three different forms: actinomycetoma, superficial skin infection or lymphocutaneous infection. A case of an 85-year-old woman with an ulcerated lesion on the back of her left hand with erythematous papules in the lymphatic tract infected by N. brasiliensis is described. The microorganism was presumptively identified by conventional and inexpensive methods for a medium complexity laboratory at the species level. The morphological characteristics of colonies, the mold smell, a positive Kinyoun stain and the presence of aerial mycelium were the key tests to identify the genus. Species level identification was confirmed by mass spectrometry (MALDI-TOF MS). The trimethoprim-sulfamethoxazole treatment was effective as this agent was active in the susceptibility testing.

Changing epidemiology of KPC-producing Klebsiella pneumoniae in Argentina: Emergence of hypermucoviscous ST25 and high-risk clone ST307.

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.

Bifidobacterium scardovii aislado de 2 muestras consecutivas de orina / Bifidobacterium scardovii isolated from 2 consecutive urine samples

La especie Bifidobacterium scardovii está constituida por bacilos gram positivos anaerobios facultativos, cuyo desarrollo es estimulado por el CO2 y la anaerobiosis. Excepcionalmente se la ha asociado a infecciones humanas. Se presenta el caso de un paciente anoso con infección urinaria por B. scardovii y Enterococcus faecalis, ambos microorganismos aislados en 2 urocultivos consecutivos. El bacilo no desarrolló en los medios de cultivo habituales, pero sí en agar chocolate en CO2 y en agar Brucella suplementado, incubados durante 72 h a 35°C. La coloración de Gram alertó acerca de su presencia al observarse abundantes bacilos gram positivos irregulares con extremos bifurcados en forma de Y, y escasos cocos gram positivos. Es importante la coloración de Gram en orinas con piuria y la siembra en medios enriquecidos por tiempos prolongados. En este caso, sin el resultado del Gram y con el desarrollo de E. faecalis, no hubiésemos advertido la presencia del agente mayoritario.

Bifidobacterium scardovii species consists of facultative anaerobic gram-positive rods whose growth is stimulated by CO2 and anaerobiosis. Exceptionally it has been associated with infections in humans. An elderly male patient with a urinary tract infection due to B. scardovii and Enterococcus faecalis is presented here; both microorganisms were isolated from two consecutive urine samples. The bacillus did not grow on standard media, but on chocolate agar incubated in CO2 and on supplemented Brucella agar in an anaerobic atmosphere, incubated for 72 h at 35°C. Gram staining with abundant irregular gram-positive rods with Y-shaped ends and some gram-positive cocci alerted to its presence. The importance of the Gram stain test in urine samples with pyuria and the growth on enriched media for long periods is highlighted here. In this case, if we had not had the Gram stain test results, and had considered only the E. faecalis growth, we would have lost the major etiologic agent.

[Bifidobacterium scardovii isolated from 2 consecutive urine samples]. / Bifidobacterium scardovii aislado de 2 muestras consecutivas de orina.

Bifidobacterium scardovii species consists of facultative anaerobic gram-positive rods whose growth is stimulated by CO2 and anaerobiosis. Exceptionally it has been associated with infections in humans. An elderly male patient with a urinary tract infection due to B. scardovii and Enterococcus faecalis is presented here; both microorganisms were isolated from two consecutive urine samples. The bacillus did not grow on standard media, but on chocolate agar incubated in CO2 and on supplemented Brucella agar in an anaerobic atmosphere, incubated for 72h at 35°C. Gram staining with abundant irregular gram-positive rods with Y-shaped ends and some gram-positive cocci alerted to its presence. The importance of the Gram stain test in urine samples with pyuria and the growth on enriched media for long periods is highlighted here. In this case, if we had not had the Gram stain test results, and had considered only the E. faecalis growth, we would have lost the major etiologic agent.

Anaerobiospirillum succiniciproducens y Desulfovibrio desulfuricans en 2 casos de bacteriemias insidiosas / Anaerobiospirillum succiniciproducens and Desulfovibrio desulfuricans in 2 cases of insidious bacteremia

Se presentan 2 casos de bacteriemias insidiosas por bacilos gram negativos anaerobios curvos, espiralados, móviles e infrecuentes en pacientes atendidos en un hospital de la ciudad de Buenos Aires. Estas bacteriemias, asociadas al aislamiento de Anaerobiospirillum y Desulfovibrio, fueron de origen poco claro y afectaron a pacientes inmunocomprometidos, con patologías simultáneas. Pruebas claves en la identificación del género Anaerobiospirillum fueron el estudio de la micromorfología, su carácter de anaerobio estricto, el resultado negativo en la prueba de catalasa, el patrón de discos de interés taxonómico, la fermentación de glucosa y la producción de β-N-acetilglucosaminidasa. El género Desulfovibrio se diferenció por el perfil presentado en las pruebas con discos, por ser asacarolítico, sin actividad de enzimas glucosídicas, y por producir desulfoviridina y H2S. Se alerta sobre la resistencia o sensibilidad intermedia de Anaerobiospirillum succiniciproducens (especie a la que correspondió el aislado de Anaerobiospirillum) a algunos de los antimicrobianos de primera línea frente a bacilos gram negativos anaerobios, como el metronidazol; fueron activas las combinaciones de aminopenicilinas con inhibidores de β-lactamasas y el imipenem. Desulfovibrio desulfuricans (especie a la que correspondió el aislado de Desulfovibrio) fue productora de β-lactamasas y resistente a las cefalosporinas; en cambio, fueron activos el metronidazol, el imipenem y la levofloxacina. La identificación confiable de estos microorganismos orienta hacia el mejor esquema terapéutico.

Two cases of insidious bacteremia by uncommon curve and spiral-shaped, motile anaerobic gram-negative rods are presented. Both of them were of an unclear origin and occurred in immunosuppressed patients with simultaneous diseases. The key tests for the identification of Anaerobiospirillum were its micromorphology, a strictly anaerobic condition, negative catalase activity, the special-potency disk profile, glucose fermentation, and β-NAG production. Desulfovibrio species was identified by all the above preliminary tests but with a different disk profile, as well as for being asaccharolytic and desulfoviridin and H2S producer. We here alert about the resistance or intermediate susceptibility of Anaerobiospirillum succiniciproducens against antimicrobial agents, such as metronidazole, one of the first-line drugs used for the treatment of anaerobic gram-negative infections. Aminopenicillins with β-lactamase-inhibitor combinations and imipenem were active for this agent. Desulfovibrio desulfuricans was β-lactamase producer and resistant to cephalosporins, while metronidazole, imipenem and levofloxacin were active. A reliable identification of these microorganisms is important for establishing the best therapeutic scheme.

[KPC-producing Klebsiella pneumoniae colonization at a University Hospital]. / Colonización por Klebsiella pneumoniae productora de carbapenemasa tipo KPC en un Hospital Universitario.

A surveillance study was conducted at a University Hospital in Buenos Aires City aimed to assess the rates of colonization with carbapenemase-producing strains of Klebsiella pneumoniae, which are bacteria of utmost epidemiological importance. To this end, rectal swabs collected from all inpatients were cultured for the presence of these bacteria. Two point prevalence surveys showed high prevalence rates (up to 25%). The following variables were evaluated in all inpatients: place of origin (home or other chronic care center), age, prolonged hospitalization, antibiotics for at least 72 hours prior to swabbing, intensive care unit requirements for at least 24 hours, mechanical ventilation assistance for more than 4 days, hemodialysis requirements, need for surgery, enteral feeding through a nasogastric tube, and functional evaluation according to the Karnofsky performance scale. The variable associated with the highest statistical significance was the use of nasogastric enteral feeding. Also, the length of stay was significantly higher and the functional status was significantly worse in colonized patients. As for the prior use of antibiotics, results were close to statistical significance but without reaching it. Measures were implemented in order to control the spread of the microorganism in the acute setting and beyond. Upon implementation of such measures, a third prevalence survey was performed that showed a decrease in the horizontal transmission of the microorganism.

[Anaerobiospirillum succiniciproducens and Desulfovibrio desulfuricans in 2 cases of insidious bacteremia]. / Anaerobiospirillum succiniciproducens y Desulfovibrio desulfuricans en 2 casos de bacteriemias insidiosas.

Two cases of insidious bacteremia by uncommon curve and spiral-shaped, motile anaerobic gram-negative rods are presented. Both of them were of an unclear origin and occurred in immunosuppressed patients with simultaneous diseases. The key tests for the identification of Anaerobiospirillum were its micromorphology, a strictly anaerobic condition, negative catalase activity, the special-potency disk profile, glucose fermentation, and ß-NAG production. Desulfovibrio species was identified by all the above preliminary tests but with a different disk profile, as well as for being asaccharolytic and desulfoviridin and H2S producer. We here alert about the resistance or intermediate susceptibility of Anaerobiospirillum succiniciproducens against antimicrobial agents, such as metronidazole, one of the first-line drugs used for the treatment of anaerobic gram-negative infections. Aminopenicillins with ß-lactamase-inhibitor combinations and imipenem were active for this agent. Desulfovibrio desulfuricans was ß-lactamase producer and resistant to cephalosporins, while metronidazole, imipenem and levofloxacin were active. A reliable identification of these microorganisms is important for establishing the best therapeutic scheme.

Colonización por Klebsiella pneumoniae productora de carbapenemasa tipo KPC en un hospital universitario / KPC-producing Klebsiella pneumoniae colonization at a University Hospital

Se realizó un estudio de vigilancia en un Hospital Universitario de la Ciudad Autónoma de Buenos Aires con el fin de determinar la prevalencia de colonización por cepas de Klebsiella pneumoniae productora de carbapenemasa, bacterias de gran importancia epidemiológica. A tal fin, se investigó su presencia en cultivos de hisopados rectales de todos los pacientes internados. Se realizaron dos cortes de prevalencia en los cuales se encontraron tasas de hasta 25%. Además, se analizaron las siguientes variables en toda la población estudiada: procedencia (domicilio u otro centro de cuidados crónicos), edad, internación prolongada, uso de antibióticos por al menos 72 horas previas al hisopado, internación en unidad de terapia intensiva, requerimientos de hemodiálisis, necesidad de cirugía, alimentación enteral mediante sonda nasogástrica, asistencia respiratoria mecánica por más de 4 días y evaluación funcional según escala de Karnofsky. La variable asociada a la colonización con mayor significación estadística fue el uso de sonda nasogástrica para alimentación enteral. Además, se observó que el tiempo de internación fue significativamente mayor y la clase funcional fue peor en los pacientes colonizados. En cuanto al uso previo de antibióticos se obtuvieron valores cercanos a la significación estadística, aunque sin alcanzarla. Con base en las variables evaluadas se implementaron medidas de contingencia con el fin de controlar la diseminación del microorganismo. Finalmente, se realizó un tercer corte de prevalencia durante la implementación de dichas medidas, el cual mostró una disminución en la transmisión horizontal del microorganismo.

A surveillance study was conducted at a University Hospital in Buenos Aires City aimed to assess the rates of colonization with carbapenemase-producing strains of Klebsiella pneumoniae, which are bacteria of utmost epidemiological importance. To this end, rectal swabs collected from all inpatients were cultured for the presence of these bacteria. Two point prevalence surveys showed high prevalence rates (up to 25%). The following variables were evaluated in all inpatients: place of origin (home or other chronic care center), age, prolonged hospitalization, antibiotics for at least 72 hours prior to swabbing, intensive care unit requirements for at least 24 hours, mechanical ventilation assistance for more than 4 days, hemodialysis requirements, need for surgery, enteral feeding through a nasogastric tube, and functional evaluation according to the Karnofsky performance scale. The variable associated with the highest statistical significance was the use of nasogastric enteral feeding. Also, the length of stay was significantly higher and the functional status was significantly worse in colonized patients. As for the prior use of antibiotics, results were close to statistical significance but without reaching it. Measures were implemented in order to control the spread of the microorganism in the acute setting and beyond. Upon implementation of such measures, a third prevalence survey was performed that showed a decrease in the horizontal transmission of the microorganism.