Lorena Porte

Bordetella holmesii in Nasopharyngeal Samples from Chilean Patients with Suspected Bordetella pertussis Infection

We read the article of Njamkepo et al. ([5][1]) with great interest. These authors report the finding of Bordetella holmesii DNA in 177 IS 481 -positive nasopharyngeal samples from French patients with suspected pertussis. They performed 4 Bordetella species-specific “in-house” real-time PCRs on

Catheter-associated bloodstream infection caused by Leifsonia aquatica in a haemodialysis patient: a case report.

Leifsonia aquatica is an aquatic coryneform rod that is capable of forming biofilms in environmental water sources. It has rarely been associated with human infections and its pathogenicity and clinical significance are uncertain. We describe a case of catheter-related bloodstream infection in a haemodialysis patient. The isolate grew on conventional media as a yellow-pigmented colony, but identification required molecular methods. Although the strain displayed reduced sensitivity to vancomycin, the clinical outcome was favourable after catheter removal and intravenous treatment with this antibiotic. Our report gives further evidence of the capability of this aquatic bacterium to cause human infection.

Presencia de Bordetella holmesii en brote epidémico de coqueluche en Chile

The incidence of whooping cough in Chile ranges from 4.1 and 7.5 per hundred thousand inhabitants. B. pertussis detection is performed by Real Time PCR (Q-PCR) directed to the insertion sequence IS481. However, this sequence is also found in the genome of B. bronchiseptica and B. holmesii. The latter is also a respiratory pathogen whose clinical features are similar to B. pertussis. However, it is important to differentiate between these species because in immunosuppressed patients B. holmesii is more likely to cause bacteremia and is less susceptible to erythromycin. The goal of this work is to measure prospectively and retrospectively the presence of B. holmesii in samples reported positive for B. pertussis in the period 2010-2011. During this period, 1994 nasopharyngeal specimens entered the laboratory for Bordetella sp. PCR, of which 224 were positive. The analysis by Q-PCR directed to the recA gene of B. holmesii of all 224 positive samples determined a prevalence of B. holmesii of 0.6% (12/1994). Because of its more aggressive behavior in immunosupressed patients and its different resistance pattern, routine screening of B. pertussis and B. holmesii is currently performed for all samples in which Bordetella sp PCR is initially detected.

Head-to-head comparison of Microflex LT and Vitek MS systems for routine identification of microorganisms by MALDI-TOF mass spectrometry in Chile

Background Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) is a new and revolutionary identification method for microorganisms and has recently been introduced into clinical microbiology in many industrialized countries in Europe and North America. Objectives Our study aimed to compare the performance and practicality of two commercial MALDI-TOF MS platforms in a head-to head manner at a routine laboratory in Chile. Methods During a five-month period in 2012–13, the diagnostic efficiency (correct identification rate) and agreement between Microflex LT (Bruker Daltonics) and Vitek MS (bioMérieux) was compared in a parallel manner to conventional identification including genotypic analysis for difficult-to-identify strains. The study included 804 microbial isolates: 252 Enterobacteriaceae, 126 non-fermenters, 36 other gram-negative rods, 279 gram-positive cocci, 32 gram-positive rods, 32 anaerobes, and 47 yeasts. Other relevant factors of the two devices such as user friendliness and connectivity were also evaluated and compared. Results Both systems correctly identified the vast majority (98%) of the isolates to the genus level. Vitek MS reached higher rates of identification to species and species complex level than Microflex LT (81% vs. 85% and 87% vs. 93%, respectively), which was mainly based on the higher performance among coagulase negative staphylococci and Candida isolates. The evaluation of user friendliness and other technical aspects showed only marginal differences, which slightly favored Vitek MS, mainly due to its ready-to-use supplies, easier connectivity and workflow integration, and availability of local technical support. Conclusions Both MALDI-TOF MS systems permitted fast and accurate identification of most microbial strains and showed a high level of user-friendliness. The observed differences were marginal and slightly favored Vitek MS, mainly due to practicality and connectivity issues within our setting.

Bacteremic pneumococcal pneumonia: serotype distribution, antimicrobial susceptibility, severity scores, risk factors, and mortality in a single center in Chile

AIMS Bacteremic pneumococcal pneumonia (BPP) is a severe condition. To evaluate seasonal distribution, mortality, serotype frequencies, antimicrobial susceptibility, and different severity scores among patients with BPP. PATIENTS AND METHODS Patients were identified by laboratory data and restricted to adulthood. Standard methods were used for serotyping and antimicrobial susceptibility. Risk factors were analyzed by univariate and multivariate methods. Severity scores (APACHE II, CURB-65 and CAP PIRO) were compared using ROC curves. RESULTS Sixty events of community-acquired BPP occurred between 2005 and 2010. A seasonal pattern was detected. Mean age was 72.1 years old (81.4% ≥ 60 years). All had a predisposing factor. Previous influenza (3.3%) or pneumococcal immunization (1.7%) was infrequent. Admission to critical units was required by 51.7%. Twenty-two serotypes were identified among 59 strains. Only one strain had intermediate resistance to penicillin (1.7%). In-hospital mortality reached 33.3%. Multivariate analysis identified a CAP PIRO score>3 (OR 29.7; IC95 4.7-187), age ≥ 65 years (OR 42.1; IC95 2.2-796), and a platelet count<100,000/μL (OR 10.9; IC95 1.2-96) as significant independent factors associated with death. ROC curve analysis did not reveal statistical differences between the three severity scores to predict death (AUC 0.77-0.90). The prognostic yield for all of them was limited (Positive Likelihood Ratio: 1.5-3.8). CONCLUSIONS BPP had a high case-fatality rate in this group of adult patients with no association to resistant isolates, and a low immunization record. Three independent factors were related to death and the prognostic yield of different severity scores was low.

Infecciones por Listeria monocytogenes, una experiencia de dos décadas: A two decade experience

Introduccion: Las infecciones por Listeria monocytogenes representan una zoonosis con escasa caracterizacion clinica en Chile. Objetivo: Analizar manifestaciones clinicas y factores de riesgo asociados a desenlace fatal. Pacientes yMetodos: Estudio retrospectivo de casos desde 1991 a 2012. Resultados: Se identificaron 23 casos, dos de ellos de aparicion nosocomial (8,7%). La edad promedio fue 68,4 anos (rango 44-90). El 70% de los casos ha ocurrido desde el ano 2003. Los factores predisponentes mas frecuentes fueron edad > 65 anos (60,9%), diabetes mellitus (40,9%) e inmunosupresion (27,3%). No se encontraron casos asociados a embarazo, infeccion por VIH o neonatos. La presentacion clinica correspondio a infeccion del SNC (39%,) con ocho casos de meningitis y uno de romboencefalitis (5%); bacteriemias (43,5%) con un caso de endocarditis infecciosa; abscesos (8,7%) y un caso de neumonia y de peritonitis bacteriana espontanea (8,7%). El consumo de alimentos de riesgo fue buscado en cinco pacientes y confirmado en cuatro (80%). Las manifestaciones clinicas mas frecuentes fueron fiebre (90,9%) y compromiso de conciencia (63,6%). La presencia de cefalea (OR 21 p < 0,05), o nauseas y/o vomitos (OR 50 p < 0,01) se asociaron en forma significativa a infeccion del SNC. Solo 45,5% recibio una terapia antimicrobiana empirica inicial adecuada y 36,4% un esquema sinergico. Ocho pacientes fallecieron (34,8%), desenlace que estuvo asociado a bacteriemia (OR 8,25; IC95 1,2-59 p < 0,05). Conclusiones: Las infecciones por L. monocytogenes parecen estar aumentando lentamente en Chile, producen infecciones en diferentes parenquimas, afectan a pacientes vulnerables, y tienen una alta letalidad, especialmente en el subgrupo con bacteriemia.

Susceptibilidad a azoles y anfotericina B de aislados de Candida spp: Experiencia de una red de salud universitaria,entre 2004 y 2010

OBJECTIVE To describe antifungal susceptibility testing surveillance (December 2004-September 2010) in Candida spp., for amphotericin B, fluconazole and voriconazole, at the Laboratorio de Microbiología, Pontificia Universidad Católica de Chile. METHOD The study was performed utilizing E test and included yeasts from invasive origin and isolates in which antifungal susceptibility testing was asked for by the patients physician. RESULTS The yeasts were mainly recovered from urine samples (n: 64), blood cultures (n: 51) and secretions (n: 24). Two hundred ninety three isolates were studied: C. albicans (38%), C. glabrata (30%), C. tropicalis (11%), C. parapsilosis (10%), C. krusei (4%) and others (7%). All Candida species were 100% susceptible to amphotericin B, except C. krusei (1/12). Fluconazoles global susceptibility in C. albicans was 91.8%, but 100% in isolates from blood cultures versus 76% in isolates from urine. C. tropicalis was 93.9% susceptible to fluconazole, C. parapsilosis, 90% and C. glabrata 30.3%. C. krusei had no susceptible isolates to fluconazole. Voriconazole resistance was mainly present in C. glabrata (11.5%). CONCLUSIONS We recommend the study of antifungal susceptibility in isolates from invasive origin, selected urine strains and C. glabrata. Fluconazole remains effective in C. albicans from blood.

Gastroenteritis aguda causada por Vibrio cholerae no-O1, no-O139 que porta una región homóloga a la isla de patogenicidad VpaI-7

Resumen Cepas patogenicas de Vibrio cholerae , el agente causal del colera, expresan generalmente uno de dos antigenos O (denominados O1 u O139). La mayoria de las cepas ambientales son no patogenicas y corresponden al tipo denominado “no-O1, no-O139”. Sin embargo, algunas cepas de este tipo son claramente patogenas y han causado brotes de gastroenteritis e infecciones extra-intestinales en humanos. Se reporta un caso clinico de gastroenteritis aguda causado por una cepa de V. cholerae no-O1, no-O139 que contiene en su genoma una region homologa a un segmento de la isla de patogenicidad VpaI-7 descrita previamente en V. parahaemolyticus . Referencias 1.- Bidinost C, Saka H, Aliendro O, Sola C, Panzetta-Duttari G, Carranza P, et al. Virulence factors of non-O1 non-O139 Vibrio cholerae isolated in Cordoba, Argentina. Rev Argent Microbiol 2004; 36: 158-63.2.- Faruque S M, Albert M J, Mekalanos J J. Epidemiology, genetics, and ecology of toxigenic Vibrio cholerae . Microbiol Mol Biol Rev 1998; 62: 1301-14.3.- Thompson F L, Iida T, Swings J. Biodiversity of

Espondilodiscitis: experiencia clínica en un hospital general de Chile

Introduccion: La espondilodiscitis (ED) implica prolongados periodos de hospitalizacion, de latencia diagnostica y riesgo de complicaciones a largo plazo. No existen publicaciones recientes en Chile al respecto. Objetivos: Caracterizar un grupo de pacientes con ED. Pacientes y Metodos: Serie clinica, que incluyo pacientes en un periodo de ocho anos. Resultados: 37 pacientes, 37,8% mujeres y 62,2% hombres, con promedio etario 66,8 anos; 64,9% adultos mayores, 35,1% diabeticos y 21,6% con co-morbilidad urologica. Los principales sintomas fueron dolor y fiebre. 89,2% tuvo elevacion de VHS. 86,5% conto con resonancia magnetica, que siempre fue confirmatoria, siendo la columna lumbar la localizacion mas frecuente (43,2%). Se identifico etiologia en 28/37 pacientes: en 71,4% cocaceas grampositivas (Staphylococcus aureus predominantemente), solo en 10,7% M. tuberculosis. Staphylococcus aureus estuvo asociado a co-morbilidades medicas en forma significativa (p < 0,05) y el grupo de bacilos gramnegativos a historia hepatobiliar y/o intestinal (p < 0,05). El metodo de mayor rendimiento fue el cultivo obtenido por puncion quirurgica. El tratamiento antimicrobiano fue indicado en promedio por 63,8 dias (IQR 53-72), con reacciones adversas en 18,9%. La estadia hospitalaria fue 38,9 dias promedio, no existiendo fallecidos durante este periodo. 18,9% presento secuelas motoras. Discusion: La mayoria de pacientes con ED correspondio a adultos mayores, siendo S. aureus la principal etiologia. Hubo una baja frecuencia de M. tuberculosis. Resulto considerable la magnitud de efectos adversos asociados a la terapia antimicrobiana y las complicaciones neurologicas.

Micobacterias atípicas en cinco pacientes adultos sin evidencias de inmunosupresión: Construyendo una experiencia

El objetivo de este trabajo es reportar la experiencia acumulada sobre infecciones por micobacterias atipicas en pacientes sin inmunosupresion. Entre el ano 2008 y 2013 se observaron cinco pacientes con infeccion por micobacterias atipicas: dos con infeccion cutanea y tres con infeccion pulmonar. Ninguno de estos pacientes tenia evidencias de inmunosupresion. Un paciente con bursitis de codo por M. chelonae tuvo un estudio citoquimico con aumento de celularidad de predominio mononuclear y desarrollo de bacterias al quinto dia; respondio favorablemente a claritromicina. Un caso con infeccion cutanea por M. fortuitum evoluciono en forma prolongada con supuracion ganglionar antes del diagnostico y el cultivo solicitado a los 13 dias fue positivo. Los tres pacientes con aislados pulmonares presentaron tos y expectoracion y tenian en comun ser mujeres en edad post-menopausica y presentar pequenos infiltrados nodulares asociados a bronquiectasias en el estudio de imagenes pulmonares, un patron descrito en la literatura cientifica. En estos tres casos, la latencia entre la toma de muestra y el informe definitivo tuvo un rango de 40 a 89 dias. El aislamiento de micobacterias atipicas en muestras de expectoracion en pacientes sin inmunosupresion se da en un contexto tipico pero plantea dificultades diagnosticas y terapeuticas. El lento crecimiento de estos microorganismos en el laboratorio contribuye a este problema.BACKGROUND Respiratory infection caused by Pneumocystis jiroveci is a common opportunistic infection in patients with human immunodeficiency virus (HIV) with CD4 counts < 200 cells/mm³. However, it has also been reported in patients with other causes of immunosuppression. OBJECTIVES To compare the characteristics, severity and mortality of respiratory infection by P. jiroveci in patients with and without HIV infection. METHODS Retrospective cohort follow-up of adult patients admitted to our hospital with infection by P. jiroveci since 2006 to 2013. RESULTS We included 82 patients with respiratory infection by P. jiroveci of which 55% (45) were not infected with HIV. In this group, 68.8% (31) had diagnosis of cancer and 20% (9) received solid-organ transplant. 57.9% (26) were hospitalized in an intensive care unit. 42.2% (19) suffered multiple organ failure (MOF), 46.7% (21) required mechanical ventilation (MV) and 40.9% (18) inotropic drugs. Mortality was 33.3% (15). Statistically significant differences were observed between groups in age (p <0.001), requirement of MV (p <0.001) inotropic drugs (p 0.001) and MOF (p <0.001). Mortality was higher in the HIV-positive group, reaching statistical significance (p 0.007). CONCLUSION Pneumocystis pneumonia mortality was higher in patients without HIV, who suffered more complications and progression to respiratory failure with MOF.Background: Respiratory infection caused by Pneumocystis jiroveci is a common opportunistic infection in patients with human immunodeficiency virus (HIV) with CD4 counts Introduccion: La infeccion respiratoria por Pneumocystis jiroveci constituye una patologia oportunista frecuente en pacientes infectados con virus de inmunodeficiencia humana (VIH), con recuentos de LTCD4