Olivia Trucco A

Resistencia a los antimicrobianos en agentes causantes de infección del tracto urinario en 11 hospitales chilenos.: Proyecto PRONARES

Background: The computer program WHONET generates a common database to analyze local or general antimicrobial resistance of bacteria. A surveillance of agents causing urinary tract infections in Chile has been performed using this program. Aim: To report the results after 12 months of urinary tract infection agent surveillance. Material and methods: Since November, 1997, a surveillance of in vitro antimicrobial resistance, using agar diffusion techniques, has been performed in 20 to 40 bacterial strains per month, isolated from 11 hospitals in the country. Results have been analyzed using WHONET program. Results: In first 12 months, 3144 strains, 1625 coming from outpatients, have been studied. Seventy four percent of isolated strains were E coli, 19% were other enterobacteria, 4.1% were non fermenting bacilli and 2.1% were Gram (+) cocci. Sixty five percent of E coli strains were resistant to ampicillin, 11% to cefazolin, 2.5% to cefuroxime, 19% to ceftriaxone, 9% to ceftazidime, 4.2% to gentamicin 1.3% to amikacin, 5.6% to ciprofloxacin, 8.4% to grepafloxacin, 4.3% to nitrofurantoin and 43% to trimeproprim/sulphamethoxazole. Eighty two percent of other enterobacteria strains were resistant to ampicillin, 45.5% to cefazolin, 33.5% to cefuroxime, 26.6% to ceftriaxone, 21.5% to ceftazidime, 30.3% to gentamicin 17.2% to amikacin, 21% to ciprofloxacin, 16.3% to grepafloxacin, 48.2% to nitrofurantoin and 44.6% to trimeproprim/sulphamethoxazole. There were differences in betalactamic resistance among hospitals. Conclusions: Noteworthy is the high resistance rates to third generation cephalosporins, evidenced when the new cutoff values for E coli and Klebsiella spp are used. This national surveillance provides updated information on antimicrobial resistance of agents causing urinary tract infections.

Nasal carriage of Streptococcus pneumoniae in elderly subjects according to vaccination status

Background: S pneumoniae is the main cause of communityacquired pneumonia in the elderly, group that concentrates 95% of deaths. Aim: To assess the prevalence of nasal carriage of S pneumoniae in institutionalized elderly patients. Material and methods: One hundred eighteen institutionalized subjects aged over 60 years (65 males) were enrolled. Since they were also participating in a controlled protocol related to the immunogenicity of an anti-pneumococcal vaccine, our investigation was also blind and randomized. According to randomization, they received pneumococcal or tetanic vaccine. Nasal swab cultures were taken at the beginning of the trial and two months after vaccination. According to recommended methods, we identified S pneumoniae, the serotypes and their antimicrobial susceptibility. Results: In the first nasal sample, 16% of subjects were positive for S pneumoniae. The second sample was positive in 12%. Of the 33 isolated serotypes, 9.1% demonstrated intermediate resistance to penicillin and 3.3% were resistant to chloramphenicol. Conclusions: The study demonstrated a greater percentage of colonized patients than in the general population. The isolated serotypes are the same that cause invasive diseases in this age group, according to data of the Institute of Public Health of Chile. There were no differences in the percentage of colonization between subjects vaccinated against S pneumoniae and control groups, after two months of follow up. Isolated strains had a low resistance to penicillin. High level resistance was not observed (Rev Med Chile 2007; 135: 160-6). (Key words: Aged; Pneumococcal vaccines; Streptococcus pneumoniae)

Red de vigilancia de resistencia antimicrobiana PRONARES: Informe primer semestre 2001

PRONARES ANTIMICROBIAL SURVEILLANCE NETWORK ONANTIMICROBIAL AGENTS RESISTANCE: REPORT OF THE FIRSTSEMESTER 2001During the last years we have seen are emerging antimicrobial agentsresistance that compromise more strains, new species and new mechanisms. InNovember 1997 we iniciated a network of antimicrobial surveillance namedPRONARES in differents hospitals that working with a unique protocol (20strains by month by syndrome) and using a computational software WHONETsurveys the resistance in Chile. The results obtained during the first semesterof 2001 shows the susceptibility pattern of 5.251 strains isolated from differentclinical syndromes. In urinary tract infections

Perfil de resistencia a los antimicrobianos en agentes causantes de infección del tracto urinario en niños chilenos: Programa de vigilancia PRONARES

Background: PRONARES (Programa Nacional de Vigilancia de Resistencia) is a national surveillance program for antimicrobial susceptibility, focused in different syndromes and among these, urinary tract infections. The work is done in a laboratory net that uses common protocols and whose data are centrally analyzed using the WHONET program. Aim: To analyze the pattern of antimicrobial susceptibility of agents causing urinary infections in children in the period 1997-1999. Material and methods: In the study period, 5,525 strains were analyzed. Of these, 2,307 came from pediatric patients (1,495 hospitalized and 803 ambulatory). Results: The most common causative agent was E. coli in 74,2% of cases, followed by Klebsiella spp in 8,2% and other agents in a lower frequency. Of E. coli strains, 74% were resistant to ampicillin, 52% to clotrimoxazole and 30% to first generation cephalosporins. These strains were sensitive to second and third generation cephalosporins, aminoglycosides, ciprofloxacin and nitrofurantoin. Strains from nosocomial or community infections had similar antimicrobial susceptibility. Klebsiella spp had a high rate of antimicrobial resistance (over 40%), that was even higher among nosocomial strains. It was 90% susceptible to ciprofloxacin and 100% to imipenem. All centers from which strains came had a similar pattern of susceptibility, with the exception of a pediatric center that had significantly higher resistance levels. Conclusions: The current therapeutic recommendations for urinary tract infections in children caused by E coli, are still pertinent, but the use of first generation cephalosporins must be cautious. The treatment of Klebsiella spp requires an individual antibiogram (Rev Med Chile 2001; 129: 877-885).

Implementación de una red nacional para la vigilancia de resistencia de agentes patógenos a antimicrobianos según síndromes clínicos

El Instituto de Salud Publica de Chile y la Sociedad Chilena de Infectologia han aunado sus esfuerzos para coordinar y co-dirigir una red nacional para la vigilancia de resistencia de agentes patogenos a antimicrobianos segun sindromes clinicos. El objetivo de esta red es establecer un sistema nacional de vigilancia de la resistencia a antimicrobianos, estandarizado y coordinado, que proporcione informacion actualizada acerca de los agentes infecciosos mas relevantes por sindromes clinicos bien definidos, por edad y por lugar de origen: hospitalaria o de la comunidad. Nos parece fundamental la participacion de todos los Servicios de Salud del pais en esta red, para obtener datos de calidad, representativos de nuestra realidad nacional, que sean de real utilidad en el manejo de los pacientes.

Difusión de H. influenzae tipo B (HI B) en contactos intrafamiliares de niños con infecciones sistémicas por este agente

The high spreading rate of Haemophilus influenzae serotype b (Hi b) infections in children has been alreadyestablished. Rifampin prophylaxis is recommended in household contacts under 4 years of age. To define the localepidemic logical situation, 31 patients with invasive Hi b disease from two pediatric hospitals of Santiago Chile werestudied (24 had meningitis, 3 facial cellulitis, 1 necrotic pneumoniae and 3 pleuropneumonia, one of them withpericarditis), looking for pharingeal carriers of Hi b among household contacts: 18% of children and 5.9% of adultscontacts were colonized with the microorganism. Secondary disease was also detected in one household contactaged 7 months. Carriers were treated with oral rifampin 20 mg/kg per day (maximun dose 600 mg per day) during 4days, which resulted in erradication of the carrier state in all cases. Twelve percent of Hi b strains were ampiciUin-resistant and 4% showed ampicillin-chloramphenicol combined resistance among index cases. All strains isolatedfrom carriers were susceptible to both drugs.(Key words: bacterial infections, Haemophilus influenzae type B, household contacts, carriers, erradication,rifamycins, rifampicin.)

Starting a national surveillance network of antibiotic resistance classified by clinical syndromes

La Sociedad Chilena de Infectología es una Sociedad Científica, que desde su fundación, en 1983, se ha preocupado de aunar a infectólogos de adultos, de niños y microbiólogos, de todo el país, en torno a tópicos de vigilancia, prevención, diagnóstico y tratamiento de las enfermedades infecciosas. En este contexto, la preocupación por la resistencia bacteriana y el uso prudente de antimicrobianos ha sido un tema prioritario para nuestra Sociedad. Muchos de nuestros miembros trabajaron arduamente en la década pasada hasta conseguir, en el año 1999, tras un esfuerzo conjunto con el Ministerio de Salud de Chile y otras organizaciones, que se promulgara la ley de regulación de venta de antimicrobianos en Chile, paso fundamental en un largo camino por recorrer aún, para mantener el “uso prudente” de estos medicamentos en nuestro país, que no sólo pasa por regular su venta, sino también otros aspectos, como su licencia, dispensación e indicación por parte nuestra, los médicos.

Estudio de susceptibilidad in vitro en Haemophilus influenzae

El genero Haemophilus comprende un grupo de bacilos Gram negativos de requerimientos fastidiosos. H. influenzae tipo b, la especie mas importante, es un cocobacilo Gram negativo pequeno, que en muestras clinicas aparece pleomorfico. Es una bacteria inmovil, no esporulada, anaerobia facultativa, que requiere dos factores de crecimiento (X-V) presentes en eritrocitos, los cuales son liberados mediante calor (agar chocolate). El principal criterio diagnostico para las infecciones por H. influenzae es la tincion de Gram y el aislamiento del microorganismo del sitio de infeccion. Por ser el Haemophilus muy fastidioso, las muestras deben ser sembradas inmediatamente, en la superficie de un agar chocolate e incubadas en ambiente de 10% de Co2. El tratamiento de las infecciones invasoras por Haemophilus tipo b, especialmente meningitis, es una emergencia medica, cualquier retardo en el inicio del tratamiento puede hacer diferencia entre la vida y la muerte, por tanto el conocimiento del patron de susceptibilidad antimicrobiana de las cepas es clave para ayudar el tratamiento empirico. El estudio de susceptibilidad antimicrobiana de rutina realizado localmente (Kirby Bauer en caso de cepas no invasivas y E-test en invasivas) debe ser realizado en HTM medium