Valeria Prado J

Situación epidemiológica de las enfermedades transmitidas por alimentos en Santiago de Chile: período 1999-2000

Background: Foodborne diseases are becoming an important cause of morbidity in Chile. In the Metropolitan Region of Chile, the Environmental Health Service started a surveillance program for foodborne diseases in 1994. In 2000, this program was complemented with an etiologic study of individuals involved in outbreaks. Aim: To report the incidence of foodborne outbreaks in the Metropolitan Region of Chile and its causative agents. Results: One hundred ninety outbreaks of foodborne diseases were reported in 1999 and 260 in 2000. The Southern Metropolitan health service had the higher incidence rates (7.5 in 1999 and 8.2 in 2000). The mean attack rates were 25% in both periods, affecting 1248 individuals in 1999 and 1774 in 2000. In 18% of outbreaks, a pathogen was identified; the most frequent agents were Salmonella Spp, Staphylococcus aureus and Shigella. In 15% of subjects, the cause was histamine or chemical agents. In the rest of the cases, the cause was not identified. The foods with higher risk of causing foodborne diseases were hot prepared dishes, home made goat cheese and meats. Conclusions: The incidence rates of foodborne disease in Metropolitan Area of Chile are high and maybe underestimate, only in a low rate of outbreaks was possible to have samples for etiologic studies. For a better understanding of this problem, timely notification of foodborne diseases must be encouraged and educational campaigns about the proper manipulation of food items must be implemented (Rev Med Chile 2002; 130: 495-501)

Tendencias en la etiología de la meningitis bacteriana aguda en niños chilenos, período 1989-1998.: Impacto de la vacuna anti-H influenzae tipo b (Hib)

Background: Acute bacterial meningitis still has a high mortality and rate of complications. Aim: To assess the impact of anti H influenzae vaccination on the epidemiology of acute bacterial meningitis in Chilean children. Material and methods: A retrospective study of hospital discharge records of patients with acute bacterial meningitis. Causative agents were studied globally, by hospital and by age group. The changes in etiology from 1989 to 1995 were also assessed. Between 1996 and 1998, only those patients with acute bacterial meningitis caused by H influenzae were recollected. Results: In the period prior to vaccination (1989-1995), 1000 cases were registered. The main causative agents were N meningitidis in 33.8%, H influenzas type b in 21.9% and S pneumoniae in 15.4%. The incidence of H influenzae decreased in the period from 36.4 to 9.9% (p<0.001) and the incidence of N meningitidis increased from 22.9 to 52.1% (p <0.001). The incidence of S pneumoniae did not change significantly. H influenzae predominated in children between 4 and 24 months of age and N meningitidis predominated in children over 25 months of age. In the period after the introduction of vaccination (1995-1998), there was a further decrease in the incidence of H influenzae from 10 to 2% (p <0.001). Until 1997, there was a considerable increase in the incidence of N meningitidis, specially in children over 25 months of age. It declined in 1998 to 38%. Conclusions: There was a reduction in the incidence of acute bacterial meningitis caused by H influenzae prior to the introduction of the vaccine against H influenzae type b. The decrease was more pronounced after the introduction of the vaccine (Rev Med Chile 2001; 129: 719-26)

Síndrome hemolítico urémico asociado a infección intestinal por Escherichia coli productora de shigatoxina (STEC) en pacientes chilenos: aspectos clínicos y epidemiológicos

Se revisan y actualizan aspectos clinicos y epidemiologicos de las infecciones por Escherichia coli productora de shigatoxina (STEC), y el sindrome hemolitico uremico (SHU). Se incluyen resultados de una vigilancia de SHU en 14 centros centinelas (2000-2002), que mostro una incidencia promedio de 3,4 casos por 100.000 ninos, 78%) en el grupo de 6 a 48 meses. Esta vigilancia reflejo una situacion endemica, con aumento en verano. Se analiza la observacion clinica protocolizada de 119 pacientes con SHU hospitalizados en la Region Metropolitana (RM) (1988 y 2002). Edad promedio: 16 meses. El 578%> tenia diarrea con sangre, 9%> no tenia diarrea previa, 60%> recibio antibacterianos, 72%> presento oligoanuria y 53%> necesito dialisis. El 31%o tuvo compromiso de conciencia y 15%o presento convulsiones. Letalidad 3%. Se analizan brotes de STEC asociados a alimentos ocurridos en la RM en el hogar (2), un jardin infantil (1) y en un servicio de neonatologia (1). Finalmente, se entregar recomendaciones para el manejo clinico y prevencion, se revisan los criterios diagnosticos, nuevas estrategias terapeuticas y progresos en el desarrollo de vacunas.

Aplicación de la capacidad bactericida del cobre en la práctica médica

BACKGROUND Copper is essential for cell metabolism in animals and plants and thus for life. Along centuries, copper has been identified as a metal containing antimicrobial properties. In recent years, laboratory assays and clinical studies have revealed that surfaces of metallic copper or its alloys, containing at least 70% copper, eliminate in a few hours several pathogenic organisms including bacterial strains associated with nosocomial infections, influenza virus, HIV, and fungi such as Candida albicans. In March 2008, the American Environmental Protection Agency (EPA), supported by scientific evidence gathered to date, registered copper as the first and only metal with antimicrobial properties. We herein review certain mechanisms proposed for the antibacterial, antiviral and antifungal activity of copper. We also discuss in vitro and clinical efficacy studies developed world wide and in Chile, focusing on bactericidal activity of copper surface areas in comparison to materials typically used in hospital environments such as stainless steel and polymers. Scientific evidence gathered to date, consistently shows that the use of copper surface areas in high contact critical points in hospitals, significantly reduces environmental bacterial load. This is associated with a decreased risk of pathogen transmission to patients and represents therefore an interesting complement to infection control programs.

Prevalencia de Chlamydia trachomatis en conjuntivitis neonatal determinada mediante las técnicas de inmuno- fluorescencia y amplificación génica

Backgrund: Chlamydia trachomatis is one of the most common identifiable infectious agents in neonatal conjunctivitis. It also causes pneumonitis, that is preceded by conjunctivitis in one third of cases. Aim: To asses the prevalence of Chlamydia trachomatis in newborns with conjunctivitis. Patients and methods: In 162 newborns, coming from 14 Primary Health Centers from Santiago de Chile, C. trachomatis was detected by indirect fluorescence and two polymerase chain reaction (PCR 1 and 2), wich amplified different sequences from the common endogenous plasmid. Those patients with positive indirect fluorescence and PCR 2 were definedas infected: Results: The prevalence of C. trachomatis was 8%, and the distribution of the positive cases was similar in the different Health Centers. Other isolates were: S. aureus (9.8%), S. pneumoniae (8%), S. viridans (6.2%) y H. influenzae (5.5%). Conclusions: The prevalence of C. trachomatis in neonatal conjunctivitis in Chile is similar to that of developed countries. Therefore, C. trachomatis should be considered in the election of antimicrobials for the treatment of neonatal conjunctivitis, to avoid ocular and respiratory complications. (Rev Med Chile 2000; 128: 758-65).

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.

Prevalencia de Escherichia coli enterohemorrágico en una zona ganadera de Argentina: Caracterización genotípica de las cepas de origen animal

Background: There is a high prevalence of infection by Enterohemorrhagic Escherichia coli (EHEC) and patients with hemolytic uremic syndrome (HUS) in Argentina. Aim: To study cattle and pigs as a possible reservoir of EHEC in Argentina. Material and methods: One hundred two healthy animals (68 cattles and 31 pigs) from a livestock in Argentina, were studied. Stool samples were obtained with a rectal swab. The strains were identified by DNA hybridization with specific gene probes detecting Shiga-like toxin 1 and 2 (Stx1, Stx2), and hly gen related to fimbrial adhesin-associated plasmid. EHEC strains were serogrouped using comercial antisera. Results: EHEC was isolated from 30 out of 68 bovines cultures (44.1%) and from 25 out of 31 pigs (58.1%). Isolates carrying genes codifying both Stx1 and Sxt2, were observed in 50% of cattle and 63.9% of pigs. The gene which codifies for hemolysin (associated to fimbrial adhesin) was observed in about 41% of EHEC isolates. Strains belonging to serogroups O26, O111, and O157 were isolated from cattle, and O111, and O157 from pigs. Conclusions: The high percentage of EHEC in both cattle and pigs and the presence of human infection-associated serogroups, suggests that these animals are a reservoir of EHEC associated with disease in humans (Rev Med Chile 2000; 128: 1335-41).

Estado actual de inmunidad para hepatitis por virus A en diversos grupos de adultos

Background: As sanitary and economic conditions improve, the prevalence of antibodies to hepatitis A is now significantly lower. Aim: To evaluate the prevalence of hepatitis A virus antibodies in healthy Chilean adults. Material and methods: Antibodies to hepatitis A virus were measured, using a commercial ELISA assay, in 215 voluntary blood donors (163 male, aged 19 to 30 years old) and 295 medical students and health personnel (156 male, aged 19 to 39 years old), residing in Valdivia, Chile. Results: Antibodies against hepatitis A virus were found in 68,2% of the total sample (351/510). Ninety percent of flood donors and 54% of health personnel and students were positive (p <0.01). Age specific prevalence in blood donors 19 to 22, 23 to 29 and 27 to 30 years old was 81,0%, 95,2% and 95,6% respectively. Among the same age groups in medical students, the prevalence was 47,9%, 53,2% and 61,9% respectively (p <0.01). Conclusions: This study indicates a reduction in the prevalence of hepatitis A virus antibodies among adults in Valdivia (Chile). Differences detected between individuals are probably related to different socioeconomic levels. Medical students have an increased risk for hepatitis A infections than the general population.

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).