Caracterización clínica y microbiológica de pacientes con trazas en Xpert MTB/RIF Ultra / Clinical and microbiological characterization of patients with Xpert MTB/RIF Ultra traces

INTRODUCCIÓN: El Xpert MTB/RIF Ultra (Ultra) ha mejorado dramáticamente el diagnóstico de la tuberculosis (TBC). Con él ha nacido la categoría de trazas, que es la menor carga bacilar detectable por este examen. OBJETIVO: Describir las características clínicas de los pacientes con presencia de trazas en el Ultra y evaluar la confirmación de la TBC como diagnóstico clínico. MATERIALES Y MÉTODOS: Estudio descriptivo de serie de casos. Se extrajo la información de fichas clínicas de pacientes con positividad a trazas. Se confrontaron datos clínicos, microbiológicos e histopatológicos. RESULTADOS: Se analizaron 21 pacientes. La edad promedio fue de 52 años. Todos los casos presentaron baciloscopias negativas. Cuatro cultivos en medio líquido MGIT fueron positivos, dos en pleura parietal, uno en líquido pleural y otro en expectoración. En pleura parietal, tres casos presentaron granulomas con necrosis caseosa y un granuloma esbozos de necrosis. En tejido pulmonar se observaron dos casos con granulomas con esbozos de necrosis y dos con granulomas no necrotizantes. Tres pacientes tenían el antecedente de TBC previa, se interpretó la positividad de trazas en ellos como falsos positivos. Finalmente se diagnosticaron 13 casos como TBC activa, donde cinco de ellos fueron TBC pleurales. La mayor concordancia clínica, microbiológica e histopatológica fue en muestras de líquido y tejido pleural. DISCUSIÓN: Se debe interpretar con cautela los hallazgos de esta prueba en muestras de vía aérea; el análisis multidisciplinario (clínica, imágenes, microbiología, histología) es crucial en las decisiones de nuestras conductas clínicas futuras. El hallazgo de trazas en pleura tiene, a nuestro parecer, un alto valor diagnóstico en el estudio de la tuberculosis en esta localización.

INTRODUCTION: Xpert MTB/RIF Ultra has dramatically changed the diagnosis of tuberculosis. A new category called traces appeared, which is the smallest amount of bacillar load detectable. OBJECTIVE: Describe the clinical characteristics of patients that present traces in Xpert MTB/RIF Ultra test, and to evaluate the confirmation of tuberculosis as clinical diagnosis. METHODS: We perform a descriptive case series study. Information was recovered from clinical records of patients with positive test for traces. Clinical, histopathological and microbiological results were confronted. RESULTS: Twenty one patients were analyzed. The mean age was 52 years-old. All cases had negative smear microscopy and four MGIT cultures were positive, two in pleural fluid and another in sputum. In parietal pleura, three cases presented granulomas with caseous necrosis, and one showed granuloma with very little necrosis. In pleural tissue we observed two cases of granulomas with traces of necrosis and two with non-necrotizing granulomas. Three patients had history of previous tuberculosis and positive traces, the test was interpreted as a false positive result. Finally, active tuberculosis was diagnosed in 13 cases, and five of them were pleural tuberculosis. The highest clinical, microbiological and histopathological agreement was in fluid and pleural tissue samples. DISCUSSION: The findings of Xpert MTB/RIF Ultra in airway samples must be interpreted carefully. Multi-disciplinary analysis is crucial in future clinical decisions. The finding of traces in pleura has, in our opinion, a high diagnostic value in the study of tuberculosis in this location.

Molecular epidemiology of hospital-onset methicillin-resistant Staphylococcus aureus infections in Southern Chile.

Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogen of public health importance. In Chile, the Cordobes/Chilean clone was the predominant healthcare-associated MRSA (HA-MRSA) clone in 1998. Since then, the molecular epidemiological surveillance of MRSA has not been performed in Southern Chile. We aimed to investigate the molecular epidemiology of HA-MRSA infections in Southern Chile to identify the MRSA clones involved, and their evolutionary relationships with epidemic international MRSA lineages. A total of 303 single inpatient isolates of S. aureus were collected in the Valdivia County Hospital (2007-2008), revealing 33% (100 MRSA/303) prevalence for HA-MRSA infections. The SCCmec types I and IV were identified in 97% and 3% of HA-MRSA, respectively. All isolates lacked the pvl genes. A random sample (n = 29) of all MRSA was studied by pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), SCCmec subtyping, agr and spa typing, and virulence genes profiling. PFGE analysis revealed the predominance (89%, 26/29) of pulsotype A and three additional pulsotypes, designated H1, I33, and G1. Pulsotype A (ST5-SCCmecI-spa-t149) is clonally related to the Cordobes/Chilean clone. Pulsotype H1 (ST5-SCCmecIVNT-spa-t002) is genetically related to the Pediatric clone (ST5-SCCmecIV). Pulsotype I33 (ST5-SCCmecIVc-spa-t002) is clonally related by PFGE to the community-associated MRSA (CA-MRSA) clone spread in Argentina, I-ST5-IVa-PVL(+). The G1 pulsotype (ST8-SCCmecIVc-spa-t024) is clonally related to the epidemic USA300 CA-MRSA. Here, we demonstrate the stability of the Cordobes/Chilean clone over time as the major HA-MRSA clone in Southern Chile. The identification of two CA-MRSA clones might suggest that these clones have entered into the healthcare setting from the community. These results emphasize the importance of the local surveillance of MRSA infections in the community and hospital settings.

Susceptibility of Arcobacter butzleri to human blood serum / Susceptibilidade de Arcobacter butzleri ao soro humano

A susceptibilidade de 10 amostras de Arcobacter butzleri ao soro humano foi estudada. A maior atividade bactericida foi encontrada no soro humano normal, com taxas de sobrevivência bacterianainversamente proporcionais à diluição do soro. As maiores taxas de sobrevivência foram obtidas com o soro inativado pelo calor. As taxas de sobrevivência decresceram com a adição de soro fresco ao inativado. O soro com valores reduzidos de gamaglobulinas e valores normais de complemento mostrou ativo efeito bactericida. Os resultados demonstraram que A. butzleri é altamente susceptível ao efeito bactericida do soro humano, sugerindo que pode ser capaz de ativar diretamente o complemento pela via alternativa.

[Antimicrobial susceptibility and resistance patterns of Staphylococcus aureus isolated from patients and carriers in Valdivia city, Chile]. / Susceptibilidad antimicrobiana y patrones de resistencia de Staphylococcus aureus aislados de pacientes y portadores en la ciudad de Valdivia, Chile.

UNLABELLED: In vitro susceptibility of nosocomial and community acquired strains of Staphylococcus aureus must be periodically evaluated because of its continuous evolution. AIM: To know the antimicrobial susceptibility of S. aureus isolated in Valdivia, to determine the prevalence of methicillin resistance and global patterns of resistance and to compare the evolution of the susceptibility along the years. MATERIAL AND METHODS: A total of 278 S. aureus strains were evaluated: 136 obtained from hospitalized patients, 50 belonged to outpatients and 92 to healthy carriers. Antimicrobial agents tested were: penicillin, oxacillin, vancomycin, gentamycin, ciprofloxacin, lincomycin and erythromycin. RESULTS: Thirty three, 28 and 1.1% of strains isolated from hospitalized, outpatients and carriers, respectively, were methicillin-resistant. Six resistance patterns were found. No vancomycin resistant strain was isolated. COMMENT: It is worrisome that 2% of S. aureus strains obtained from hospitalized patients showed intermediate resistance to vancomycin.

Susceptibilidad antimicrobiana y patrones de resistencia de Staphylococcus aureus aislados de pacientes y portadores en la ciudad de Valdivia, Chile / Antimicrobial susceptibility and resistance patterns of Staphylococcus aureus isolated from patients and carriers in Valdivia city, Chile

La susceptibilidad in vitro de Staphylococcus aureus adquirido, tanto en el ambiente hospitalario como en la comunidad, debe ser monitorizada periódicamente por su continua evolución. Objetivos: Conocer la susceptibilidad antimicrobiana de cepas de S. aureus aisladas en Valdivia, determinar la prevalencia de cepas resistentes a meticilina y sus respectivos patrones de resistencia, analizar la evolución de esta susceptibilidad a través de los años. Material y Métodos: Se evaluaron 278 cepas de S. aureus: 136 obtenidas de pacientes hospitalizados, 50 de pacientes ambulatorios y 92 de portadores. Los antimicrobianos ensayados fueron: penicilina, oxacilina, vancomicina, gentamicina, ciprofloxacina, lincomicina y eritromicina.

In vitro susceptibility of nosocomial and community acquired strains of Staphylococcus aureus must be periodically evaluated because of its continuous evolution. Aim: To know the antimicrobial susceptibility of S. aureus isolated in Valdivia, to determine the prevalence of methicillin resistance and global patterns of resistance and to compare the evolution of the susceptibility along the years. Material and Methods: A total of 278 S. aureus strains were evaluated: 136 obtained from hospitalized patients, 50 belonged to outpatients and 92 to healthy carriers. Antimicrobial agents tested were: penicillin, oxacillin, vancomycin, gentamycin, ciprofloxacin, lincomycin and erythromycin. Results: Thirty three, 28 and 1.1 percent of strains isolated from hospitalized, outpatients and carriers, respectively, were methicillin-resistant. Six resistance patterns were found. No vancomycin resistant strain was isolated. Comment: It is worrisome that 2 percent of S. aureus strains obtained from hospitalized patients showed intermediate resistance to vancomycin.

Genotipos de Staphylococcus aureus con fenotipo meticilino resistente, aislados de pacientes del Hospital Base de Valdivia / Genotypes of Staphylococcus aureus strains with methicillin resistant phenotype

Background: Methicillin resistant strains of Staphylococcus aureus (MRSA) are an important cause of nosocomial infections. Aim: To determine the genotypes of MRSA strains. Material and methods: Fifty five strains of MRSA, isolated from patients hospitalized in Hospital Base Valdivia, were studied. The phenotype was determined through MicroScan® in all strains and by minimum inhibitory concentration (MIC) in 41. The genotype of the strains was analyzed by a duplex polymerase chain reaction (PCR) of the mecA gene, amplifying eight hypervariable DNA regions associated to such gene. Results: According to MIC, 88 percent of strains had a pattern of resistance against multiple antimicrobial (penicillin, ampicillin, cephradine, gentamycin, ciprofloxacin, íincomycin and erythromycin). Vancomicin resistan strains were not detected. Only 53 strains (96 percent) had at least one of the eight hypervariable regions and were classified as MRSA. Genotypic patterns types 15 were the most commonly detected in 38 percent and 34 percent of strains, respectively. MicroScan® erroneously classified five strains in an incorrect phenotype, according to results obtained with duplex PCR. MIC results did not differ from those of duplex PCR. Conclusions: Duplex- PCR is a useful tool to detect hyper variable regions associated to mecA gene.

Antibodies anti-Chlamydia pneumoniae and anti-Mycoplasma pneumoniae in patients with negative serology for hantavirus. Retrospective study

The seroprevalence of Chlamydia pneumoniae and Mycoplasma pneumoniae in hantavirus seronegative patients, who had symptoms and signs compatible with pneumonia was established. For this purpose we used the indirect fluorescent antibody test. Titers > or =1:16 for C. pneumoniae and M. pneumoniae were found in 8.6 percent and 17.1 percent of the serum, respectively, showing evidence of recent or current infection

Antibodies anti-Chlamydia pneumoniae and anti-Mycoplasma pneumoniae in patients with negative serology for hantavirus. Retrospective study.

The seroprevalence of Chlamydia pneumoniae and Mycoplasma pneumoniae in hantavirus seronegative patients, who had symptoms and signs compatible with pneumonia was established. For this purpose we used the indirect fluorescent antibody test. Titers > or = 1:16 for C. pneumoniae and M. pneumoniae were found in 8.6% and 17.1% of the serum, respectively, showing evidence of recent or current infection.

[Infection by intestinal protozoa and helminths in schoolchildren from riverside sectors, with different fecal contamination levels, of Valdivia River, Chile]. / Infección por protozoos y helmintos intestinales en escolares de sectores ribereños, con distintos niveles de contaminación fecal, del río Valdivia, Chile.

During 1993, the prevalences of infection by intestinal protozoa and helminths (IPH) in the riverside schoolchildren population of two sectors of Valdivia river, with different levels of fecal contamination, were compared in relation to their contact with river water (swimming, bathing) and basic sanitation elements (BSE) of their houses: feces and garbage disposal, and water supply. Populations of children from sectors A (n = 418), with significatively greater (SG) total coliform most probable number (MPN), and sector B (n = 400), were examined. PAFS test was used for the stool examination of one sample, from each child. The global prevalence of infection by IPH was similar in A (74.8%) and B (72.5%) sectors. From 10 identified IPH, only Entamoeba histolytica and Hymenolepis nana showed prevalences of infection SG in sector A, than in sector B. The contact of the children with the water of the river showed association with SG prevalences for E. histolytica, Entamoeba coli and Endolimax nana in sector B and for E. histolytica in sector A. No sanitary condition for the different BSE contributed to SG prevalences for E. histolytica, Ascaris lumbricoides and Trichuris trichiura in both sectors, and for E. coli in sector B. The contact with the river water and the different BSE contributed to prevalences SG in 5 and 3 IPH in sectors B and A, respectively. The results suggest that a project in study for the development of a treatment plant of wastewater in sector A, could contribute to control infection by IPH. But, this measure must be associated with improvement of the BSE, health education, and application of chemotherapy measures for geohelminthosis in both sectors.

Diagnostic fiberoptic bronchoscopy in patients with community-acquired pneumonia. Comparison between bronchoalveolar lavage and telescoping plugged catheter cultures.

We compared the diagnostic value of quantitative cultures of bronchoalveolar lavage (BAL) and telescoping plugged catheter (TPC) samples in 40 patients with moderately severe community-acquired pneumonia (CAP). None had received antibiotics previously. BAL quantitative cultures were performed in 13 control patients without pneumonia. In 28 (70 percent) patients, TPC cultures yielded > or = 10(3) cfu/ml of a pathogenic bacterium in pure culture. In 27 of these cases and in four additional cases, BAL cultures yielded > or = 10(3) cfu/ml. BAL cultures from the control group were sterile in seven cases, yielded normal flora in three cases, and yielded microorganisms thought to be not significant in two cases. Microbiologic agreement was reached by both TPC and BAL for 32 (84 percent) of 38 microorganisms recovered. Quantitative cultures from both techniques correlated very well (r = 0.71, p < 0.0001). We conclude that both TPC and BAL have similar accuracy to determine etiologic diagnosis of CAP. There was good qualitative and quantitative agreement between both techniques.

[Microbiological study of urethritis in men]. / Estudio microbiológico de la uretritis en el hombre.

From 1985 to 1987 we obtained urethral samples from 453 patients with a clinical diagnosis of urethritis. N gonorrhoeae was isolated in 55%, a rate that increased along the study period. The most common other agent was U urealyticum alone or in combination with other organisms. Among 82 patients, the incidence of chlamydia trachomatis was 19%. The proportion of Beta-lactamase producing strains among N gonorrhoeae varied form 7% in 1985 to 13% in 87 and 3% in 1988.

[Detection of Chlamydia trachomatis in urethral samples by direct immunofluorescence]. / Detección de Chlamydia trachomatis en muestras uretrales mediante inmunofluorescencia directa.

The presence of Chlamydia trachomatis was studied by the direct immunofluorescence test, as also was that of Neisseria gonorrhoeae, Mycoplasma and Ureaplasma by the standard methods, in 82 patients with urethral discharge. Ch. trachomatis was found in 19.5% (16) of the cases and in 11 of them (68.8%) there was association with the other bacteria investigated. This eleven patients presented a scanty gelatinous discharge.

[Neisseria gonorrhoeae: 3 years of surveillance of antibiotic susceptibility and search of beta-lactamase-producing strains]. / Neisseria gonorrhoeae: tres años de vigilancia en la susceptibilidad antibiótica y pesquisa de cepas productoras de beta lactamasa.

247 strains of N gonorrhoeae were isolated from 453 patients with acute urethritis from 1985 to 1987. 19 strains produced beta-lactamase for a 7, 13 and 3% incidence in each of the 3 years. MIC between 1 and 8 micrograms/ml or between 65 and 256 micrograms/ml were found in 2 groups of beta lactamase producing strains. An increase in the sensitivity rate (81%) to penicillin of non beta-lactamase producing strains was observed in this period. The sensitivity to erythromycin and chloramphenicol remained constant while a slight increase in resistance to tetracycline was observed.

Susceptibilidad de Dermatofitos, Candida y otros hongos frente a ácidos grasos y escualeno / Susceptibility of dermatophytes, Candida and other fungos apposite fatty and squalene acids

La piel contiene distintos ácidos grasos y otros compuestos que han demostrado poseer una actividad antimicótica. Se estudió la acción inibitoria de los ácidos grasos undecilénico, láurico, mirístico y del escualeno sobre dermatofitos, candida sp., Aspergillus sp., Aspergillus sp. y Scopulariopsis sp. Para ello se usó el método de dilución en agar de Chmel y Louria con un inóculo definido por Negroni. El ácido undecilénico inhibió al 100% de los dermatofitos con concentraciones inferiores o iguales a 64 µg/ml de medio. En cambio, la mayoría de las cepas de Aspergillus y Scopulariopsis crecieron con concentraciones superiores a 128 µg/ml. El ácido láurico inhibió al 53.2% de las cepas con concentraciones inferiores o iguales a 128 µg/ml. Fueron particularmente sensibles (100%) las cepas de Trichophyton verrucosum (64µg/ml). El escualeno y el ácido mirístico presentaron una mínima actividad antimicotica

Susceptibilidad in vitro de dermatofitos, Candida y otros hongos frente a Tolciclato: estudio comparativo de dos inóculos / In vitro susceptibitity of dermatophytes, Candida and other fungi to tolciclate: comparative studies using 2 inocula

Se estudió la actividad de tolciclato frente a dermatofitos, Candida y otros hongos con dos inóculos diferentes. Con el inóculo definido por Negroni los dermatofitos fueron inhibidos en un 100% a una concentración inferior o igual a 2,56 microng/ml. En cambio con el inóculo definido por Bianchi, el 100% de estas cepas fue susceptible a concentraciones inferiores o iguales a 0,08 microns/ml. El 100% de las cepas de C. albicans fueron resistentes a 5,12 microng/ml con ambos inóculos

Susceptibilidad in vitro de algunos hongos y bacterias frente a un S-acil derivado de tiosalicilamida / Susceptibility in vitro of some fungi and bacteria to S-acyl derivated from thiosalicylamide

Se estudió el comportamiento de dermatofitos, Candida y otros hongos como también de bacterias aisladas en Valdivia, Chile, frente a S-acetil-N-terbutil tiosalicilamida. El 94,5% de los dermatofitos fueron inhibidos por CIM iguales o inferiores a 64 micron-grama/ml. de medio del S-acetil derivado. El 41,7% de las cepas de C. albicans y el 25% de las cepas de Scopulariopsis brevicaulis fueron resistentes a concentraciones de 128 micron-grama/ml. de medio. Staphylococcus aureus fue inhibido en un 100% a concentraciones iguales o inferiores a l6 micron-grama/ml

Búsqueda de reservorios animados e inanimados de microorganismos patogenos y oportunistas en una unidad de tratamiento intensivo / Search fr animate and inanimate reservoirs of pathogenic and oportunistic microorganisms in an intensive care unit

Se realizó búsqueda de reservorios animados e inanimados de STAPHYLOCOCCUS AUREUS, enterobacterias y bacilos Gram negativos no fermentadores, en la Unidad de Tratamiento Intensivo del Hospital Hohn Kennedy, Valdivia. Se tomaron muestras de secreción faríngea y manos del personal asistencial en dos oportunidades separadas por 30 días. Las muestras ambientales se recolectaron de superficies, desinfectantes, jabones y lubrificantes, ropa de cama, respiradores, material médico estéril y vectores. Se usó el antibiotipo como marcador epidemiológico. Las especies más aisladas en personal fueron STAPHYLOCOCCUS AUAREUS (43,8%) y ENTEROBACTERAGGLOMERANS (28,1%); en embiente se aisló con mayor frecuencia ENTEROBACTER AGGLOMERANS (18,4%) y PSEUDOMONAS PUTIDA y SERRATIA MARCESCENS (13,2%). El antibiotipo demostró que cepas de una misma especie estaban diseminadas tanto en el ambiente como en el personal