Enterobacterias portadoras de KPC en un hospital universitario / KPC-producing Enterobacteriaceae in a university hospital

La resistencia a carbapenemes en enterobacterias representa una situación de alto impacto clínico debido a las limitadas opciones terapéuticas disponibles para el tratamiento de las infecciones causadas por estos microorganismos multirresistentes que cursan con altas tasas de morbilidad y mortalidad. En nuestro país, en los últimos 5 años, se observó la diseminación de aislamientos de Klebsiella pneumoniae portadores de carbapenemasa de tipo KPC pertenecientes al ST258, clon diseminado mundialmente. En nuestro hospital la incidencia de episodios fue aumentando, especialmente la infección del sitio quirúrgico y las bacteriemias. En el último bienio se observó la diseminación del mecanismo de resistencia a otras enterobacterias y probablemente a otros secuenciotipos de K pneumoniae con mayor sensibilidad a antibióticos no ß-lactámicos. Se hace necesario instaurar las correctas medidas de prevención y control para evitar la diseminación de estos patógenos.

The presence of carbapenem -resistant Enterobacteriaceae in clinical settings represents a concerning issue due to the limited therapeutic options available for the treatment of the infections caused by these multi-drug resistant bacteria which usually have high mortality rates. The spread of Klebsiella pneumoniae isolates belonging to ST258 was observed in the last 5 years in our country. In our hospital the number of episodes has grown with the years and the most prevalent infections were the surgical site and bacteremia. In the last 2 years KPC spread to other Enterobacteriaceae and probably to other STs in K pneumoniae which showed different susceptibility patterns to non ß-lactamic antimicrobials. We believe that it is vital to install the appropriate measures to prevent and control the dissemination of these microorganisms.

Clinical, microbiological, and genetic characteristics of heteroresistant vancomycin-intermediate Staphylococcus aureus bacteremia in a teaching hospital.

The emergence of vancomycin intermediate Staphylococcus aureus (VISA) and heterogeneous VISA (hVISA) is of major concern worldwide. Our objective was to investigate the prevalence, phenotypic and molecular features of hVISA strains isolated from bacteremic patients and to determine the clinical significance of the hVISA phenotype in patients with bacteremia. A total of 104 S. aureus blood isolates were collected from a teaching hospital of Argentina between August 2009 and November 2010. No VISA isolate was recovered, and 3 out of 92 patients (3.3%) were infected with hVISA, 2 of them methicillin-resistant S. aureus (MRSA) (4.5% of MRSA). Macro Etest and prediffusion method detected 3/3 and 2/3 hVISA respectively. Considering the type of bacteremia, the three cases were distributed as follows: two patients had suffered multiple episodes of bacteremia (both hVISA strains recovered in the second episode), while only one patient had suffered a single episode of bacteremia with hVISA infection. MRSA bloodstream isolates exhibiting the hVISA phenotype were related to HA-MRSA Cordobes clone (ST5-SCCmec I-spa t149) and MRSA Argentinean pediatric clone (ST100-SCCmec IVNV-spa t002), but not to CA-MRSA-ST30-SCCmec IV-spa t019 clone that was one of the most frequent in our country. Although still relatively infrequent in our hospital, hVISA strains were significantly associated with multiple episodes of bacteremia (p=0.037) and genetically unrelated.

Enterococcus spp.: Resistencia antimicrobiana en infecciones intrahospitalarias / Enterococcus spp.: Antimicrobial resistance in hospital- acquired infections / Enterococcus spp.: ResistÛncia antimicrobiana em infecþ§es intra-hospitalares

Entre los años 1996 y 2010 se estudiaron 1873 aislamientos de Enterococcus spp. pertenecientes a pacientes internados en un hospital universitario de la Ciudad Autónoma de Buenos Aires con infección intrahospitalaria. El 64,2% y el 30,4% de los aislamientos correspondieron a E. faecalis y E. faecium, respectivamente. En el periodo estudiado las infecciones por Enterococcus spp. representaron entre el 8% y el 10% del total de las infecciones nosocomiales. La prevalencia de E. faecium aumentó de un 1,5% en el año 1996 a un 4% en 2010. El primer aislamiento de enterococo resistente a vancomicina se detectó en el año 1998 y correspondió a un E. faecium y en el año 2004 se halló en E. faecalis. Actualmente más del 70% de los aislamientos de E. faecium son resistentes a vancomicina, no así en E. faecalis donde la resistencia es ocasional. No se detectó resistencia a linezolid ni a tigeciclina en Enterococcus spp.(AU)

One thousand eight hundred and seventy-three Enterococcus spp. isolates belonging to patients undergoing hospital-acquired infections at the University Hospital of Buenos Aires city were studied between the years 1996 and 2010. A total of 64.2% and 30.4% of the isolates were identified as E. faecalis y E. faecium respectively. The infections caused by Enterococcus spp. represented from 8% to 10% of the total number of the nosocomial infections in the period studied. The E. faecium prevalence increased from 1.5% in 1996 to 4% in 2010. The first vancomycin-resistant Enterococcus faecium was detected in the year 1998 and in the year 2004 this resistance was detected in E. faecalis as well. At present, more than 70% of the E. faecium isolates show vancomycin resistance; on the contrary, in the case of E. faecalis, this resistance is unusual. Resistance to linezolid or to tigecycline has not been detected in Enterococcus spp. so far.(AU)

Entre os anos 1996 e 2010 estudaram-se 1873 isolamentos de Enterococcus spp. pertencentes a pacientes internados num Hospital Universitário da Cidade Aut¶noma de Buenos Aires com infecþÒo intra-hospitalar. 64,2% e 30,4% dos isolamentos corresponderam a E. faecalis e E. faecium respectivamente. No estudado as infecþ§es por Enterococcus spp. representaram entre 8% e 10% do total das infecþ§es nosocomiais. A prevalÛncia de E. faecium aumentou de 1,5% no ano 1996 para 4% em 2010. O primeiro isolamento de enterococo resistente a vancomicina foi detectado no ano 1998 e correspondeu a um E. faecium e no ano 2004 foi achado em E. faecalis. Atualmente mais de 70% dos isolamentos de E. faecium sÒo resistentes a vancomicina, mas nÒo é assim em E. faecalis onde a resistÛncia é ocasional. NÒo se detectou resistÛncia a linezolid nem a tigeciclina em Enterococcus spp.(AU)

Enterococcus spp: Resistencia antimicrobiana en infecciones intrahospitalarias / Enterococcus spp: Antimicrobial resistance in hospital-acquired infections / Enterococcus spp: Resistência antimicrobiana em infecções intra-hospitalares

Entre los años 1996 y 2010 se estudiaron 1873 aislamientos de Enterococcus spp. pertenecientes a pacientes internados en un hospital universitario de la Ciudad Autónoma de Buenos Aires con infección intrahospitalaria. El 64,2% y el 30,4% de los aislamientos correspondieron a E. faecalis y E. faecium, respectivamente. En el periodo estudiado las infecciones por Enterococcus spp. representaron entre el 8% y el 10% del total de las infecciones nosocomiales. La prevalencia de E. faecium aumentó de un 1,5% en el año 1996 a un 4% en 2010. El primer aislamiento de enterococo resistente a vancomicina se detectó en el año 1998 y correspondió a un E. faecium y en el año 2004 se halló en E. faecalis. Actualmente más del 70% de los aislamientos de E. faecium son resistentes a vancomicina, no así en E. faecalis donde la resistencia es ocasional. No se detectó resistencia a linezolid ni a tigeciclina en Enterococcus spp.

[Candida albicans outbreak in a neonatal intensive care unit]. / Brote de candidemia por Candida albicans en neonatología.

The appearance of Candida albicans in three patients made physicians investigate an outbreak. Outbreak description and microbiologic screening: Case 1 developed C. albicans in the placenta culture and in the blood culture carried out on the 8th day of birth. Four days after this candidemia, C. albicans was recovered in a catheter tip of a second neonate (case 2) and finally five days later other newborn (case 3) developed C. albicans in the hemoculture. After that, the hands of all caregivers as well as case 3's incubator, case 1's mother, and from all nine neonates in the unit were studied with swabs. A wet mount was done to all swabs and then they were cultured in Chromagar Candida and SDA. All C. albicans were studied by RAPD. RAPD study showed that C. albicans recovered from placenta and blood cultures of case 1, the catheter tip of case 2 and the blood culture of case 3, resulted to be identical and these yeasts were related to the C. albicans from the mouth of case 1 mother and the mouth of another colonized newborn. C. albicans was not found in the others swabs. The isolations of identical C. albicans allowed to suppose the horizontal transmission from the case 1, that had acquired it congenitally. Not only isolation of unusual Candida species would be an alert. Despite patients' personal factors to justify a fungal infection, the recovery of C. albicans in a short period of time should warn physicians about the possibility of a horizontal transmission.

Brote de candidemia por Candida albicans en neonatología / Candida albicans outbreak in a neonatal intensive care unit

El aislamiento de Candida albicans en tres pacientes (dos en hemocultivos)sugirió la existencia de un brote epidémico. En el caso 1 se aisló C. albicans dela placenta de la madre, así como de una muestra de sangre del recién nacidotomada a los ocho días de vida. Cuatro días después del diagnóstico de estacandidemia, se aisla C. albicans en la punta del catéter de otro neonato (caso 2),y cinco días después en los hemocultivos de un tercer neonato (caso 3). Antela sospecha de un brote epidémico, se investigó la existencia de colonización.Se tomaron mediante hisopo muestras de las manos del personal, la cuna delcaso 3, la madre del caso 1 y los nueve neonatos internados. Cada hisopo sesembró en Chromagar Candida® y agar glucosado de Sabouraud.Los aislamientos de C. albicans recuperados fueron estudiados por RAPD.El estudio por RAPD mostró que los aislamientos de C. albicans de la placenta,los de los hemocultivos de los casos 1 y 3, y el de la punta de catéter del caso2 eran genotípicamente idénticos. Se aisló C. albicans de otros dos neonatos(boca e ingle en uno e ingle en el otro) y de la boca de la madre del caso 1.Esta última cepa y la de la boca del neonato colonizado estarían genéticamenterelacionadas con la de los casos mencionados. No se aisló C. albicans delresto de los hisopos. Los aislamientos de C. albicans idénticos permitieronsuponer la trasmisión horizontal a partir del caso 1, quien la había adquiridocongénitamente. Aunque los pacientes tengan factores de riesgo quejustifiquen una infección por Candida, el aislamiento de C. albicans en variasmuestras en un tiempo corto, debe hacer sospechar la posibilidad de latrasmisión horizontal de la infección(AU)

The appearance of Candida albicans in three patients made physiciansinvestigate an outbreak. Outbreak description and microbiologic screening:Case 1 developed C. albicans in the placenta culture and in the blood culturecarried out on the 8th day of birth. Four days after this candidemia, C. albicanswas recovered in a catheter tip of a second neonate (case 2) and finally fivedays later other newborn (case 3) developed C. albicans in the hemoculture.After that, the hands of all caregivers as well as case 3’s incubator, case 1’smother, and from all nine neonates in the unit were studied with swabs. A wetmount was done to all swabs and then they were cultured in ChromagarCandida and SDA. All C. albicans were studied by RAPD. RAPD study showedthat C. albicans recovered from placenta and blood cultures of case 1, thecatheter tip of case 2 and the blood culture of case 3, resulted to be identicaland these yeasts were related to the C. albicans from the mouth of case 1mother and the mouth of another colonized newborn. C. albicans was notfound in the others swabs. The isolations of identical C. albicans allowed tosuppose the horizontal transmission from the case 1, that had acquired itcongenitally. Not only isolation of unusual Candida species would be an alert.Despite patients’ personal factors to justify a fungal infection, the recovery ofC. albicans in a short period of time should warn physicians about thepossibility of a horizontal transmission(AU)