Alberto Fica

Analysis of Molecular Epidemiology of Chilean Salmonella enterica Serotype Enteritidis Isolates by Pulsed-Field Gel Electrophoresis and Bacteriophage Typing

ABSTRACT Human Salmonella enterica serotype Enteritidis infections emerged in Chile in 1994. S. enterica serotype Enteritidis phage type 1 isolates predominated in the north, and phage type 4 isolates predominated in the central and southern regions. A study was planned to characterize this epidemic using the best discriminatory typing technique. Research involved 441 S. enterica serotype Enteritidis isolates, including clinical preepidemic samples (n = 74; 1975 to 1993) and epidemic (n = 199), food (n = 72), poultry (n = 57), and some Latin American (n = 39) isolates. The best method was selected based on a sample of preepidemic isolates, analyzing the discriminatory power (DP) obtained by phage typing and randomly amplified polymorphic DNA and pulsed-field gel electophoresis (PFGE) analysis. The highest DP was associated with BlnI PFGE-bacteriophage typing analysis (0.993). A total of 38 BlnI patterns (B patterns) were identified before the epidemic period, 19 since 1994, and only 4 in both periods. Two major clusters were identified by phylogenetic analysis, and the predominant B patterns clustered in the same branch. Combined analysis revealed that specific B pattern-phage type combinations (subtypes) disappeared before 1994, that different genotypes associated with S. enterica serotype Enteritidis phage type 4 had been observed since 1988, and that strain diversity increased before the expansion of S. enterica serotype Enteritidis in 1994. Predominant subtype B3-phage type 4 was associated with the central and southern regions, and subtype B38-phage type 1 was associated with the north (P < 0.0001). Food and poultry isolates matched the predominant S. enterica serotype Enteritidis subtypes, but isolates identified in neighboring countries (Peru and Bolivia) did not match S. enterica serotype Enteritidis subtypes identified in the north of Chile. The results of this work demonstrate that genetic diversity, replacement, and expansion of specific S. enterica serotype Enteritidis subtypes were associated with epidemic changes.

Tipificación fágica de aislados de salmonella enteritidis de muestras clínicas,alimentarias y avícolas en Chile

Since 1994 an extensive epidemic of infections with Salmonella enteritidis (S. enteritidis) has affected Chile. In order to understand the diversity of infective sources, the possible origin of the epidemic, and the epidemiological relationships between clinical, food, and poultry isolates, we carried out phage typing of three groups of samples: 1) 310 S. enteritidis clinical samples collected between 1975 and 1996, 2) 47 food isolates obtained during S. enteritidis outbreaks, and 3) 27 strains isolated in surveillance studies of poultry-raising establishments. With the clinical samples, a total of 13 phage types were identified, 2 isolates could not be typed, and 1 was considered atypical. The phage types that were identified most frequently were 1 (56.8%) and 4 (31.3%), trailed by type 8 (4.8%) and type 28 (1.9%). Over time and in different regions of the country there were major changes in the distribution of the phage types. In the first years of collection the only phage types registered were 8 and 28, which disappeared around 1980 and then began reappearing sporadically in 1996. With the gradual S. enteritidis expansion that started in 1988, in the central and southern areas of the country phage type 4 began to appear; that type had not been found before in Chile. In 1991 in the northern area of the country phage type 1 began to predominate; it was another type that had not been reported before in Chile. In the food isolates the only phage types identified were 1 and 4, which were also the most common in the poultry isolates. Phage typing of S. enteritidis has proved to be useful in guiding the epidemiological analysis of the infections caused by this pathogen.

A case of myopericarditis associated to Campylobacter jejuni infection in the southern hemisphere

Myopericarditis is an infrequent complication of acute diarrheal illness due to Campylobacter jejuni, and it has been mainly reported in developed nations. The first case detected in Chile--an upper-middle income country--that is coincidental with the increasing importance of acute gastroenteritis associated to this pathogen, is described. Recognition of this agent in stools requires special laboratory techniques not widely available, and it was suspected when a young patient presented with acute diarrhea, fever, and chest pain combined with electrocardiogram (EKG) abnormalities and elevated myocardial enzymes. C. jejuni myopericarditis can easily be suspected but its detection requires dedicated laboratory techniques.

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.

Opinión del Comité Consultivo de Inmunizaciones Sociedad Chilena de Infectología: Vacuna neumocóccica conjugada en niños y la emergencia de serotipo 19A

Inclusion of the 10-valent pneumococcal conjugated vaccine (PCV10) in the Chilean infant vaccination Program in 2011 was followed by a reduction of hospital admissions and pneumonia-related deaths in this age group. However, a progressive increase of serotype 19A pneumococcal isolates (not included in PCV10) has been observed. According to the analysis of pneumococcal strains performed by the national reference laboratory of the Institute of Public Health as part of a national surveillance on invasive pneumococcal infections, the relative proportion of serotype 19A isolates increased from <5% before 2010 to 12-23% in years 2014-2015. Serotype 19A represented 4-8% of the isolates in the pre-vaccine era among children less than 2 years, increasing to 25% during 2014. This increase has been documented in two-thirds of the national territory. Aimong children <5 years of age, 25% of 19A serotype isolates from non-meningeal infections were penicillin resistant wheras from meningeal infections near 100% were penicillin resistant. Genetic analysis indicates that 48% of these 19A strains belong to clonal complex 320, recognized for its pandemic potential and high antimicrobial resistance. Among children, most invasive infections secondary to serotype 19A have occurred in patients fully vaccinated with PCV10. These epidemiological changes indicate an increase in invasive pneumococcal infections by serotype 19A in Chile and the need to control this problem by changing the current PCV10 for the PCV13 vaccine containing serotype 19A.: Inclusion of the 10-valent pneumococcal conjugated vaccine (PCV10) in the Chilean infant vaccination Program in 2011 was followed by a reduction of hospital admissions and pneumonia-related deaths in this age group. However, a progressive increase of serotype 19A pneumococcal isolates (not included in PCV10) has been observed. According to the analysis of pneumococcal strains performed by the national reference laboratory of the Institute of Public Health as part of a national surveillance on invasive pneumococcal infections, the relative proportion of serotype 19A isolates increased from <5% before 2010 to 12-23% in years 2014-2015. Serotype 19A represented 4-8% of the isolates in the pre-vaccine era among children less than 2 years, increasing to 25% during 2014. This increase has been documented in two-thirds of the national territory. Aimong children <5 years of age, 25% of 19A serotype isolates from non-meningeal infections were penicillin resistant wheras from meningeal infections near 100% were penicillin resistant. Genetic analysis indicates that 48% of these 19A strains belong to clonal complex 320, recognized for its pandemic potential and high antimicrobial resistance. Among children, most invasive infections secondary to serotype 19A have occurred in patients fully vaccinated with PCV10. These epidemiological changes indicate an increase in invasive pneumococcal infections by serotype 19A in Chile and the need to control this problem by changing the current PCV10 for the PCV13 vaccine containing serotype 19A.

Clinical relevance of rhinovirus infections among adult hospitalized patients

Abstract Human rhinovirus (HRV) is an emerging viral pathogen. Aim To characterize a group of patients admitted due to infection by this agent in a general hospital in Chile. Methods Cases were identified by RT-PCR for 1 year through active surveillance of patients admitted with severe respiratory illness. Diagnosis was not available during hospitalization. Thirty-two cases were identified, 90% were ≥60 years old or had co-morbid conditions. Human rhinovirus-related admissions represented 23.7% of hospitalization due to severe acute respiratory infections among adults and ranked second to influenza (37.8%). Patients presented with pneumonia (68.8%), decompensated chronic lung conditions (21.9%), heart failure or influenza-like illness (6.3% each). Admission to intensive or intermediate care units was required by 31.2% and in-hospital mortality reached 12.5%. A CURB-65 score ≥3 was significantly associated to in-hospital mortality (p <0.05). Most patients received antibiotics (90%). Conclusions Human rhinovirus infections in elderly patients with co-morbid conditions are associated with hospitalizations, requiring critical or semi-critical antibiotics use. A high CURB-65 score was associated to in-hospital mortality.

Evaluación de las condiciones de manejo de catéteres vasculares periféricos en pacientes adultos

Evaluation of peripheral vascular catheter management conditions in adult patients Background: Peripheral venous vascular catheters (PVC) are devices that are not free of complications, and CDC, Atlanta, recommendations are followed in order to prevent them. However, available information in Chile on this matter is scarce. Objective: To evaluate if management of PVC fulfill safety recommendations in adult patients in a general hospital. Methods: Cross-sectional study evaluating compliance with 4 measures: patch condition, circuit condition, justification of PVC and registration of the device on medical records. Results: We evaluated 102 PVC, and 45.1% met all the measures assessed. Deficiencies were identified in 54.9% and included shortfalls in every one of the 4 topics measured. Compliance among those with iv sets was higher in comparison with those using mechanical valve needleless connectors (2.5 vs 1.9 points in a scale from 0 to 4; p < 0.001). In addition, compliance decreased progressively along time of use (Pearson coefficient -0.4; p < 0.05). Conclusions: Deficiencies on the safety management of PVC were frequent in clinical practice and worsen with days. Needleless mechanical connectors use is associated with a lower compliance.BACKGROUND Peripheral venous vascular catheters (PVC) are devices that are not free of complications, and CDC, Atlanta, recommendations are followed in order to prevent them. However, available information in Chile on this matter is scarce. OBJECTIVE To evaluate if management of PVC fulfill safety recommendations in adult patients in a general hospital. METHODS Cross-sectional study evaluating compliance with 4 measures: patch condition, circuit condition, justification of PVC and registration of the device on medical records. RESULTS We evaluated 102 PVC, and 45.1% met all the measures assessed. Deficiencies were identified in 54.9% and included shortfalls in every one of the 4 topics measured. Compliance among those with iv sets was higher in comparison with those using mechanical valve needleless connectors (2.5 vs 1.9 points in a scale from 0 to 4; p < 0.001). In addition, compliance decreased progressively along time of use (Pearson coefficient -0.4; p < 0.05). CONCLUSIONS Deficiencies on the safety management of PVC were frequent in clinical practice and worsen with days. Needleless mechanical connectors use is associated with a lower compliance.

Infecciones en pacientes reumatológicos asociadas a corticosteroides y antagonistas del factor de necrosis tumoral α

A great diversity of infectious agents can affect patients that use steroids at immunosuppressive doses or tumor necrosis factor alpha (TNF-alpha) antagonists. The list of participating microorganisms is more restricted in the case of anti TNF-alpha blockers. Overlapping agents include intracellular bacteria, Mycobacterium tuberculosis, geographic fungal agents that have the ability to establish granulamotous infections, herpes zoster, and reactivation of chronic hepatitis B virus infection. An important conceptual issue for these infections is the existence of a threshold prednisone daily dose for the emergence of opportunistic infections but higher levels of immunosuppression and cofactors are required in the case of Pneumocystis jiroveci and cytomegalovirus infections. In order to prevent these threats, a detailed medical evaluation is needed before prescription to detect potential risks and manage them properly. Prevention rules must be prescribed in every case, that include common sense behaviors, vaccines, and in selected cases, chemoprophylaxis for latent tuberculosis (TB) infection, P. jiroveci pneumonia (PCP) or other specific requirements. Latent TB infection is probable and requires chemoprophylaxis in the case of remote or recent exposure to a patient with lung TB, a positive tuberculin or interferon-gamma release assay result or residual lung scars in a chest x-ray exam. PCP prevention is suggested when the patient reaches a daily dose of prednisone of 30 mg but might be needed at lower doses in case of other concomitant immunosuppressive drugs or when lymphopenia arises shortly after prednisone initiation.

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.