The Burkholderia contaminans prevalent phenotypes as possible markers of poor clinical outcomes in chronic lung infection of children with cystic fibrosis.

Burkholderia contaminans, a species of the Burkholderia cepacia complex-prevalent in certain Latin-American and European countries-can cause chronic pulmonary infection in persons with cystic fibrosis. Our aim was to gain insights into long-term lung infections with a focus on correlating how bacterial phenotypic traits in the chronic infection impact on patients' clinical outcome. Genotypic characteristics of 85 B. contaminans isolates recovered from 70 patients were investigated. For 16 of those patients, the clinical status and bacterial phenotypic characteristics, e.g. several virulence factors, phenotypic variants, and the antimicrobial susceptibility pattern, were evaluated. Two clones were found in the whole bacterial population: (i) the multiresistant ST 872 PCR-recA-RFLP-HaeIII-K-pattern clone, which carries a pathogenic island homologous to BcenGI11 of B. cenocepacia J2315, and (ii) the ST 102 PCR-recA-RFLP-HaeIII-AT-pattern clone. The emergence of certain bacterial phenotypes in the chronic infection such as the nonmucoid phenotype, small colony variants, brownish pigmented colonies, and hypermutators, proved to be, together with coinfection with Pseudomonas aeruginosa, the possible markers of more challenging infections and poor prognosis. The presence of cocolonizers and the bacterial phenotypes that are especially adapted to persist in long-term respiratory tract infections have a crucial role in patients' clinical outcomes.

Primer reporte de Escherichia coli diarreogénica en población pediátrica ambulatoria con diarrea atendida en la ciudad de La Plata, Argentina / First report of diarrheagenic Escherichia coli in pediatric outpatient population with diarrhea in La Plata, Argentina

Resumen Escherichia coli diarreogénica comprende un grupo heterogéneo de cepas que presentan diversos factores de virulencia y causan diferentes síndromes diarreicos. Los patotipos más estudiados son Escherichia coli enteropatogénica (EPEC), Escherichia coli enterotoxigé-nica (ETEC), Escherichia coli enteroagregativa (EAEC), Escherichia coli enteroinvasiva (EIEC) y Escherichia coli productora de toxina Shiga (STEC). El objetivo de este estudio fue estimar la frecuencia de infección de los diversos patotipos de E. coli diarreogénica en una población pediátrica ambulatoria con diarrea, atendida en el Hospital Sor María Ludovica de La Plata, Argentina, durante el período mayo-octubre de 2017. Los patotipos fueron detectados mediante la amplificación molecular de ocho genes de virulencia característicos. Se estudiaron las heces de 211 ninos (76% menores de 5 años). Se detectó infección con E. coli diarreogénica en el 12,3% (n = 26/211) de los niños con diarrea. Los patotipos identificados fueron EAEC, ETEC (todos lt positivos), EPEC y STEC (stx2 y eae positivos). El patotipo EAEC fue prevalente en todos los grupos etarios, mientras que los patotipos ETEC, EPEC y STEC solamente se observaron en niñnos menores de 5 anños. Este estudio constituye el primer reporte de detección por técnicas de amplificación molecular de Escherichia coli diarreogénica en una población pediátrica ambulatoria con diarrea, de la zona de La Plata. Se necesitan estudios más amplios que incluyan la caracterización de los aislamientos abarcando un mayor número de genes, controles asintomáticos, distintas épocas del ano y población de diversas áreas geográficas para esclarecer la relevancia de la infección por E. coli diarreogénica en niños de Argentina.

Abstract Diarrheagenic Escherichia coli is a heterogeneous group of strains that presents various virulence factors and causes different diarrheal syndromes. The most studied pat-hotypes are enteropathogenic Escherichia coli (EPEC), enterotoxigenic Escherichia coli (ETEC), enteroaggregative Escherichia coli (EAEC), enteroinvasive Escherichia coli (EIEC) and Shiga toxin-producing Escherichia coli (STEC). The objective was to estimate the frequency of infec-tion of diarrheagenic E. coli pathotypes in children with diarrhea, attended at the Sor María Ludovica Hospital in La Plata, Argentina, during the period May-October 2017. E. coli pathotypes were detected by molecular amplification of eight characteristic virulence genes. The feces of 211 children (76% under 5 years) were studied. Infection with diarrheagenic E. coli was detected in 12.3% of the samples. The pathotypes were EAEC (10.43%), ETEC (1.42%, all of them positive for thermolabile toxin), EPEC (0.95%) and STEC (0.47%, positive for Shiga toxin 2). The EAEC pathotype was prevalent in children of all age groups, while ETEC, EPEC and STEC were only observed in children under 5 years of age. This study constitutes the first report of diarrheagenic Escherichia coli detection in an outpatient pediatric population with diarrhea from La Plata, using molecular amplification techniques. Broader future studies, including the charac-terization of the isolates with the largest number of genes, asymptomatic controls, different times of the year and population from different geographic areas will be necessary to clarify the relevance of diarrheagenic E. coli infection in children from Argentina.

[First report of diarrheagenic Escherichia coli in pediatric outpatient population with diarrhea in La Plata, Argentina]. / Primer reporte de Escherichia coli diarreogénica en población pediátrica ambulatoria con diarrea atendida en la ciudad de La Plata, Argentina.

Diarrheagenic Escherichia coli is a heterogeneous group of strains that presents various virulence factors and causes different diarrheal syndromes. The most studied pathotypes are enteropathogenic Escherichia coli (EPEC), enterotoxigenic Escherichia coli (ETEC), enteroaggregative Escherichia coli (EAEC), enteroinvasive Escherichia coli (EIEC) and Shiga toxin-producing Escherichia coli (STEC). The objective was to estimate the frequency of infection of diarrheagenic E. coli pathotypes in children with diarrhea, attended at the Sor María Ludovica Hospital in La Plata, Argentina, during the period May-October 2017. E. coli pathotypes were detected by molecular amplification of eight characteristic virulence genes. The feces of 211 children (76% under 5 years) were studied. Infection with diarrheagenic E. coli was detected in 12.3% of the samples. The pathotypes were EAEC (10.43%), ETEC (1.42%, all of them positive for thermolabile toxin), EPEC (0.95%) and STEC (0.47%, positive for Shiga toxin 2). The EAEC pathotype was prevalent in children of all age groups, while ETEC, EPEC and STEC were only observed in children under 5 years of age. This study constitutes the first report of diarrheagenic Escherichia coli detection in an outpatient pediatric population with diarrhea from La Plata, using molecular amplification techniques. Broader future studies, including the characterization of the isolates with the largest number of genes, asymptomatic controls, different times of the year and population from different geographic areas will be necessary to clarify the relevance of diarrheagenic E. coli infection in children from Argentina.

Estudio multicéntrico argentino sobre la utilidad del panel de neumonía de FilmArray® / Argentine multicenter study on the utility of the FilmArray® pneumonia panel

Resumen Las infecciones de las vías respiratorias inferiores se encuentran entre aquellas en las que el uso inadecuado de antimicrobianos es frecuente, por lo que es fundamental contar con una prueba diagnóstica rápida, sensible y específica. El sistema de FilmArray es un análisis de PCR múltiple con un panel de neumonía que incluye 26 microorganismos y 7 marcadores de resistencia antimicrobiana. Los objetivos de este estudio fueron: a) establecer la correlación entre los cultivos cuantitativos para agentes bacterianos de muestras de vías respiratorias inferiores (MRVB) y la detección fenotípica de mecanismos de resistencia con los correspondientes resultados de FilmArray; b) determinar el cambio terapéutico generado con el informe del resultado inmediato. Se incluyó un total de 194 MRVB correspondientes a 191 pacientes con neumonía y se documentaron 277 bacterias. FilmArray identificó 253/277 (91%) bacterias y 161/277 (58%) se aislaron del cultivo, 58 (23%) coincidieron con el mismo recuento, 116 (46,7%) dieron mayores recuentos con FilmArray y 72 (28,9%) fueron detectadas por este método pero el cultivo fue negativo. Se detectaron marcadores de resistencia antimicrobiana en 63 aislados, pero solo 28 fueron confirmados por métodos fenotípicos. Estos resultados podrían haber provocado cambios en el tratamiento antibiótico en el 74,6% (174/194). FilmArray es una herramienta útil para optimizar el tratamiento antimicrobiano en pacientes con neumonía.

Abstract Lower respiratory tract infections are among those in which the inappropriate use of antimicrobials is common, so it is essential to have a rapid, sensitive and specific diagnostic test. The FilmArray system is a multiplex PCR assay with a pneumonia panel that includes 26 microorganisms and 7 antibiotic resistance markers. The objectives of this study were: a) to establish the correlation between quantitative cultures for bacterial agents from lower respiratory tract samples (MRVB) and the phenotypic detection of resistance mechanisms with the corresponding results of FilmArray b) to determine the therapeutic change generated with the immediate result report. A total of 194 MRVB corresponding to 191 patients with pneumonia were included and 277 bacterial strains were documented. FilmArray identified 253/277 (91%) bacteria and 161/277 (58%) were isolated from culture, 58 (23%) matched the same count, 116 (46.7%) yielded higher counts with FilmArray, and 72 (28.9%) with negative culture were detected by this method. Antibiotic resistance markers were detected in 63 strains, but only 28 were confirmed by phenotypic methods. These results may cause changes in the antimicrobial treatment in 74.6% (174/194). FilmArray is a useful tool to optimize antimicrobial therapy in patients with pneumonia.

Resumo As infecções do trato respiratório inferior estão entre aquelas em que o uso inadequado de antimicrobianos é comum, por isso é essencial um teste diagnóstico rápido, sensível e específico. O sistema FilmArray é um ensaio de PCR multiplo com um painel de pneumonia que inclui 26 microrganismos e 7 marcadores de resistência antimicrobiana. Os objetivos deste estudo foram: a) estabelecer a correlação entre as culturas quantitativas de agentes bacterianos de amostras do trato respiratório inferior (MRVB) e a detecção fenotípica de mecanismos de resistência com os resultados correspondentes do FilmArray b) determinar a alteração terapêutica gerada com o relatório de resultado imediato. Um total de 194 MRVB correspondendo a 191 pacientes com pneumonia foram incluídos e 277 cepas bacterianas foram documentadas. FilmArray identificou 253/277 (91%) bactérias e 161/277 (58%) foram isoladas da cultura, 58 (23%) coincidiram com mesma contagem, 116 (46,7%) deram contagens mais altas com FilmArray e 72 (28,9%) foram detectados por este método, mas a cultura foi negativa. Marcadores de resistência antimicrobiana foram detectados em 63 cepas, mas apenas 28 foram confirmados por métodos fenotípicos. Esses resultados puderam causar alterações no tratamento antibiótico em 74,6% (174/194). FilmArray é uma ferramenta útil para otimizar a terapia antimicrobiana em pacientes com pneumonia..

Persistent infection with a rotavirus vaccine strain in a child suffering from Severe Combined Immunodeficiency in Argentina.

Due to the high burden of disease associated with rotavirus, the massive vaccination in children before six months of age has been encouraged. Currently licensed oral live vaccines have shown low risk of associated adverse events in the general population. Noteworthy, postmarketing reports of severe gastroenteritis with persistent vaccine viral shedding in children with severe combined immunodeficiency (SCID) have led companies to include this inborn error of immunity as an additional contraindication. SCID is not usually screened in newborns from developing countries. Therefore, the administration of live attenuated vaccines represents the first contact of these patients with life-threatening pathogens. We describe a clinical case of an infant with SCID who suffered from persistent rotavirus symptomatic diarrhea after receiving the rotavirus oral vaccine and was found to be infected with the vaccine strain. This case attempts to contribute to the discussion of those diseases that need to be incorporated into a screening program since an early diagnosis permits clinicians to withhold live attenuated immunization.

Fungal infections in hematopoietic stem cell transplantation in children at a pediatric children's hospital in Argentina.

Our primary objective was to describe the incidence of proven or probable invasive fungal infections (IFIs), a devastating complication of hematopoietic stem cell transplant (HSCT), in HCST in a middle-income country. Secondary objectives were to describe factors associated with IFIs and outcomes. In this single center retrospective study, pediatric patients who underwent a first allogeneic or autologous HSCT from 1998 to 2016 were included. Of the 251 HSCT recipients: 143 transplants were allogeneic and 108 were autologous. Overall, 23 (9%) experienced an IFI, mostly due to yeasts (83%). IFIs were more common in allogeneic HSCT (18/143, 13%) than in autologous HSCT (5/108, 5%; P = .045). Of the 23 patients with IFIs, 14 (61%) died, but only 1 directly from IFI (pulmonary aspergillosis). Overall survival at 3 years was 0.42 ± 0.11 in patients with IFIs and 0.60 ± 0.37 in those without IFIs (P = .049). In Argentina, IFIs during HSCT are common. Recipients of allogeneic HSCT are at higher risk, and IFI is associated with reduced overall survival. Future work should focus on interventions to reduce and improve IFI outcomes in children undergoing transplants in low- and middle-income countries.

Burkholderia puraquae sp. nov., a novel species of the Burkholderia cepacia complex isolated from hospital settings and agricultural soils.

Bacteria from the Burkholderia cepacia complex (Bcc) are capable of causing severe infections in patients with cystic fibrosis (CF). These opportunistic pathogens are also widely distributed in natural and man-made environments. After a 12-year epidemiological surveillance involving Bcc bacteria from respiratory secretions of Argentinean patients with CF and from hospital settings, we found six isolates of the Bcc with a concatenated species-specific allele sequence that differed by more than 3 % from those of the Bcc with validly published names. According to the multilocus sequence analysis (MLSA), these isolates clustered with the agricultural soil strain, Burkholderia sp. PBP 78, which was already deposited in the PubMLST database. The isolates were examined using a polyphasic approach, which included 16S rRNA, recA, Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), DNA base composition, average nucleotide identities (ANIs), fatty acid profiles, and biochemical characterizations. The results of the present study demonstrate that the seven isolates represent a single novel species within the Bcc, for which the name Burkholderia puraquae sp. nov. is proposed. Burkholderia puraquae sp. nov. CAMPA 1040T (=LMG 29660T=DSM 103137T) was designated the type strain of the novel species, which can be differentiated from other species of the Bcc mainly from recA gene sequence analysis, MLSA, ANIb, MALDI-TOF MS analysis, and some biochemical tests, including the ability to grow at 42 °C, aesculin hydrolysis, and lysine decarboxylase and ß-galactosidase activities.

Candidemias en pediatría: distribución de especies y sensibilidad a los antifúngicos / Candidemia in Pediatrics: Species distribution and antifungal susceptibility

Las infecciones graves causadas por levaduras del género Candida son frecuentes en la población hospitalaria. Debido a las diferencias en la distribución de especies y la sensibilidad a los antifúngicos según el área geográfica y el tipo de paciente, resulta importante estudiar la epidemiología de cada institución. Con este propósito, hemos realizado un estudio retrospectivo y descriptivo sobre las candidemias ocurridas en el Hospital de Ninos «Superiora Sor María Ludovica¼ de la ciudad de La Plata. En un período de 6 años (2010-2015) se registraron 177 episodios de candidemia. Las especies predominantes fueron Candida albicans (45%) y Candida parapsilosis (28%). Las salas de internación con mayor cantidad de episodios fueron las unidades de terapia intensiva de pediatría, la neonatal y la cardiovascular (58%). En los casos donde se realizaron pruebas de sensibilidad a los antifúngicos, no se observó resistencia a la anfotericina B en todo el período y la resistencia a azoles se limitó a 4 aislamientos de especies menos frecuentes.

Serious infections caused by Candida yeasts are frequent in the hospital population. Due to differences in species distribution and antifungal susceptibility testing depending on the geographic area and the type of patient, it is important to study the epidemiology of each institution. For this purpose, we conducted a retrospective, descriptive study on the occurrence of candidemia in the Children's Hospital "Superiora Sor María Ludovica" of the city of La Plata. In a 6-year period (2010-2015), 177 candidemia episodes were recorded. The predominant species were Candida albicans (45%) and Candida parapsilosis (28%). The hospital wards with the highest number of candidemia episodes were the pediatric, neonatal and cardiovascular intensive care units (58%). No resistance to amphotericin B was observed throughout the period whereas resistance to azoles was limited to 4 strains of less frequent species.

[Candidemia in Pediatrics: Species distribution and antifungal susceptibility]. / Candidemias en pediatría: distribución de especies y sensibilidad a los antifúngicos.

Serious infections caused by Candida yeasts are frequent in the hospital population. Due to differences in species distribution and antifungal susceptibility testing depending on the geographic area and the type of patient, it is important to study the epidemiology of each institution. For this purpose, we conducted a retrospective, descriptive study on the occurrence of candidemia in the Children's Hospital "Superiora Sor María Ludovica" of the city of La Plata. In a 6-year period (2010-2015), 177 candidemia episodes were recorded. The predominant species were Candida albicans (45%) and Candida parapsilosis (28%). The hospital wards with the highest number of candidemia episodes were the pediatric, neonatal and cardiovascular intensive care units (58%). No resistance to amphotericin B was observed throughout the period whereas resistance to azoles was limited to 4 strains of less frequent species.

Genetic diversity of Burkholderia contaminans isolates from cystic fibrosis patients in Argentina.

A total of 120 Burkholderia cepacia complex isolates collected during 2004-2010 from 66 patients in two cystic fibrosis reference centers in Argentina were analyzed. Burkholderia contaminans was the species most frequently recovered (57.6%), followed by Burkholderia cenocepacia (15%), a species distribution not reported so far. The recA-PCR-based techniques applied to the B. contaminans isolates revealed that 85% of the population carried the recA-ST-71 allele. Our results showed the utility of BOX-PCR genotyping in analyzing B. contaminans diversity. This approach allowed us to address clonal transmission during an outbreak and the genetic changes occurring in infecting bacteria over the course of chronic infection.

Fourier transform infrared spectroscopy for rapid identification of nonfermenting gram-negative bacteria isolated from sputum samples from cystic fibrosis patients.

The accurate and rapid identification of bacteria isolated from the respiratory tract of patients with cystic fibrosis (CF) is critical in epidemiological studies, during intrahospital outbreaks, for patient treatment, and for determination of therapeutic options. While the most common organisms isolated from sputum samples are Pseudomonas aeruginosa, Staphylococcus aureus, and Haemophilus influenzae, in recent decades an increasing fraction of CF patients has been colonized by other nonfermenting (NF) gram-negative rods, such as Burkholderia cepacia complex (BCC) bacteria, Stenotrophomonas maltophilia, Ralstonia pickettii, Acinetobacter spp., and Achromobacter spp. In the present study, we developed a novel strategy for the rapid identification of NF rods based on Fourier transform infrared spectroscopy (FTIR) in combination with artificial neural networks (ANNs). A total of 15 reference strains and 169 clinical isolates of NF gram-negative bacteria recovered from sputum samples from 150 CF patients were used in this study. The clinical isolates were identified according to the guidelines for clinical microbiology practices for respiratory tract specimens from CF patients; and particularly, BCC bacteria were further identified by recA-based PCR followed by restriction fragment length polymorphism analysis with HaeIII, and their identities were confirmed by recA species-specific PCR. In addition, some strains belonging to genera different from BCC were identified by 16S rRNA gene sequencing. A standardized experimental protocol was established, and an FTIR spectral database containing more than 2,000 infrared spectra was created. The ANN identification system consisted of two hierarchical levels. The top-level network allowed the identification of P. aeruginosa, S. maltophilia, Achromobacter xylosoxidans, Acinetobacter spp., R. pickettii, and BCC bacteria with an identification success rate of 98.1%. The second-level network was developed to differentiate the four most clinically relevant species of BCC, B. cepacia, B. multivorans, B. cenocepacia, and B. stabilis (genomovars I to IV, respectively), with a correct identification rate of 93.8%. Our results demonstrate the high degree of reliability and strong potential of ANN-based FTIR spectrum analysis for the rapid identification of NF rods suitable for use in routine clinical microbiology laboratories.

Analisis de la resistencia a los antibacterianos en los aislamientos de pacientes internados en el Hospital de Niños Superiora Sor María Ludovica durante el año 2005 / An analysis of the resistance to antibacterials in germs isolated from in patients at the Superiora Sor María Ludovica children's Hospital, 2005

El tratamiento empírico con antibióticos adecuados requiere del conocimiento de la epidemiología bacteriana local. Para ello se realizo un estudio retrospectivo de la sensibilidad a los antibióticos de los microorganismos recuperados durante 2005 de los pacientes internados.Los microorganismos mas frecuentemente aislados fueron: Staphylococcus aureus (S. aureus) (24.1 %), Escherichia coli (E. coli) (15.8 %), Klebsiella pneumoniae (K. Pneumoniae) (12.4%) y Pseudomonas aeruginosa (P. aeruginosa) (10.1 %). En S. aureus la resistencia a meticilina supero el 40 %, con alto porcentaje de resistencia acompañante a otros antibióticos y total sensibilidad a TMS. La resistencia en E. coli y K. pneumoniae a cefalosporinas de tercera generación llego a niveles alarmantes (34.1% y 60%, respectivamente). P. aeruginosa mostró altos niveles para ceftazidima, carbapenemes y gentamicina (entre el 10% y 20%), mantenido total sensibilidad al colistin.Resulta evidente que el control de la infección Hospitalaria y el uso racional de los antimicrobianos son las únicas alternativas para impedir el incremento de la residencia de las bacterias.

Estreptococo ß hemolítico grupo A en pacientes pediátricos: análisis de la sensibilidad a los macrólidos / Group A Beta hemolytic streptococcus in pediatrics: analysis of its sensitivity to macrolides

El streptococcus pyogenes (estreptococo beta hemolítico grupo A) (S. pyogenes) es el microorganismo aislado mas frecuentemente en la faringo amigdalitis bacteriana. No existen hasta el momento cepas resistentes a penicilina, por lo tanto sigue siendo el antibiótico de elección para su tratamiento. En los últimos años se ha detectado un aumento de la resistencia a antibióticos de la familia de los macrólidos, tanto en nuestro país como en el resto del mundo. Debido a esta realidad decidimos vigilar que ocurre con los aislamientos de S. pyogenes obtenidos de muestras de hisopados de fauces en nuestro hospital.Se estudiaron 152 cepas entre mayo de 2002 y mayo de 2006. El cultivo y la identificación bioquímica se realizaron por la metodología convencional. Las pruebas de sensibilidad se ensayaron de acuerdo a las normas CLSI (Clinical and Laboratory Standards Institute). Se realizo antibiograma por difusión en agar Mueller-Hinton con 5% de sangre ovina, probándose penicilina, eritromicina y clindamicina.Todos los aislamientos estudiados fueron sensibles a los antibióticos ensayados. Dado su bajo costo y su baja selección de resistencia en el resto de la flora oro-faríngia, la penicilina sigue siendo el antibiótico de elección para el tratamiento de las faringitis estreptocóccicas.

Estreptococo ß hemolítico grupo A en pacientes pediátricos. Análisis de la sensibilidad a los macrólidos / Group A Beta hemolytic streptococcus in pediatrics. analysis of its sensitivity to macrolides

El streptococcus pyogenes (estreptococo beta hemolítico grupo A) (S. pyogenes) es el microorganismo aislado mas frecuentemente en la faringoamigdalitis bacteriana. No existen hasta el momento cepas resistentes a penicilina, por lo tanto sigue siendo el antibiótico de elección para su tratamiento. En los últimos años se ha detectado un aumento de la resistencia a antibióticos de la familia de los macrólidos, tanto en nuestro país como en el resto del mundo. Debido a esta realidad decidimos vigilar que ocurre con los aislamientos de S. pyogenes obtenidos de muestras de hisopados de fauces en nuestro hospital.Se estudiaron 152 cepas entre mayo de 2002 y mayo de 2006. El cultivo y la identificación bioquímica se realizaron por la metodología convencional. Las pruebas de sensibilidad se ensayaron de acuerdo a las normas CLSI (Clinical and Laboratory Standards Institute). Se realizo antibiograma por difusión en agar Mueller-Hinton con 5% de sangre ovina, probándose penicilina, eritromicina y clindamicina.Todos los aislamientos estudiados fueron sensibles a los antibióticos ensayados. Dado su bajo costo y su baja selección de resistencia en el resto de la flora oro-faríngia, la penicilina sigue siendo el antibiótico de elección para el tratamiento de las faringitis estreptocóccicas

Analisis de la resistencia a los antibacterianos en los aislamientos de pacientes internados en el Hospital de Niños Superiora Sor María Ludovica durante el año 2005 / An analysis of the resistance to antibacterials in germs isolated from in patients at the Superiora Sor María Ludovica childrens Hospital, 2005

El tratamiento empírico con antibióticos adecuados requiere del conocimiento de la epidemiología bacteriana local. Para ello se realizo un estudio retrospectivo de la sensibilidad a los antibióticos de los microorganismos recuperados durante 2005 de los pacientes internados.Los microorganismos mas frecuentemente aislados fueron: Staphylococcus aureus (S. aureus) (24.1 %), Escherichia coli (E. coli) (15.8 %), Klebsiella pneumoniae (K. Pneumoniae) (12.4%) y Pseudomonas aeruginosa (P. aeruginosa) (10.1 %). En S. aureus la resistencia a meticilina supero el 40 %, con alto porcentaje de resistencia acompañante a otros antibióticos y total sensibilidad a TMS. La resistencia en E. coli y K. pneumoniae a cefalosporinas de tercera generación llego a niveles alarmantes (34.1% y 60%, respectivamente). P. aeruginosa mostró altos niveles para ceftazidima, carbapenemes y gentamicina (entre el 10% y 20%), mantenido total sensibilidad al colistin.Resulta evidente que el control de la infección Hospitalaria y el uso racional de los antimicrobianos son las únicas alternativas para impedir el incremento de la residencia de las bacterias.