Infecciones invasivas por estreptococos de los grupos A, C y G en la Argentina / Invasive infectios due to group A, C and G streptococci in Argentina

Streptococcus pyogenes (estreptococo beta-hemolítico del grupo A) (SGA) y Streptococcus dysgalactiae subsp. equisimilis, (estreptococos beta-hemolíticos grupos C y G) (SDSE) son capaces de provocar enfermedades graves como la fascitis necrotizante y el síndrome de shock tóxico estreptocócico (SSTE) y de causar complicaciones posinfecciosas. El objetivo de este trabajo fue presentar resultados de un estudio multicéntrico y compararlo con diferentes estudios descriptivos previos sobre infecciones invasivas por estreptococos beta-hemolíticos de los grupos A, C y G, también realizados en la Argentina. Se incluyeron 54 pacientes de 0 a 15 años con infecciones invasivas por SGA (N=50) o SDSE (N=4) en forma prospectiva entre julio de 2011 y junio de 2012 en 28 centros de 17 ciudades argentinas. Se aisló S. pyogenes en 28 pacientes que presentaron bacteriemia, 6 de ellas sin foco. Cuatro pacientes (7,4%) presentaron SSTE, en todos los casos por S. pyogenes. La mortalidad fue del 2,0% para SGA. La evolución de los pacientes fue peor en los tres estudios anteriores respecto del actual: mayor porcentaje de casos de SSTE (diferencias no significativas) y mayor mortalidad (diferencia significativa respecto de dos estudios previos). Es probable que la morbimortalidad haya decrecido en esta última década en la Argentina posiblemente debido al uso temprano de clindamicina en las infecciones invasivas por S. pyogenes y SDSE, aunque no se puede descartar la diferente circulación de cepas virulentas. Esta apreciación además está sesgada por la inclusión de pacientes de distintos centros con diferentes formas de presentación inicial (AU)

Streptococcus pyogenes (group A ß-hemolytic streptococcus (GAS)) and Streptococcus dysgalactiae subsp. equisimilis (group C and G ß-hemolytic streptococcus (GCGS)) may cause severe diseases such as necrotizing fasciitis and streptococcal toxic shock syndrome (STSS) as well as postinfectious complications. The aim of this report was to present the results of a multicenter study and compare them with the results of different previous descriptive studies on invasive infections due to beta-hemolytic streptococcus groups A, C, and G that were also conducted in Argentina. Forty-five patients between 0 and 15 years of age with invasive infections due to GAS (N=50) or GCGS (N=4) were prospectively included in the study between July 2011 and June 2012 from 28 centers in 17 Argentine cities. S. pyogenes was isolated in 28 patients who presented with bacteremia, without a focus in six. Four patients (7.4%) had STSS, due to S. pyogenes in all of them. In patients with GAS, mortality rate was 2.0%. Outcome of the patients was worse in previous studies than in the present one: Percentages of cases with STSS (no significant difference) and mortality (significant difference) were higher. It is probable that over the last decade morbidity and mortality have decreased in Argentina, possibly due to the early use of clindamycin in invasive infections due to S. pyogenes and GCGS, although a different circulation of virulent strains cannot be ruled out. Additionally, this observation is biased by the inclusion of patients from different centers with different presentations at onset (AU)

Rabies control in Mexico.

Rabies in dogs was unknown in the Americas before the arrival of the Spanish "Conquistadores". Until the mid-1980s rabies in animals and, in turn in humans, changed little from year to year, with the number of dog vaccinations reported annually rarely reaching one million. In Mexico, the national rabies control programme using mass parenteral vaccination of dogs started in 1990 with about seven million dogs vaccinated the same year. The number of vaccinated dogs exceeded 10 and 15 million in 1995 and 2005, respectively. Modern cell culture-based inactivated rabies virus vaccines were used. A key factor for the success of the dog rabies control program was the supply of potent canine rabies vaccines. Between 1990 and 2005, more than 150 million vaccine doses from 300 lots were administered. Each lot was tested for potency prior to use in the field. The required minimum content of rabies virus antigen for vaccines was 2 IU, in accord with WHO standards. Testing revealed antigen contents ranging from 3.28 to 5.59 IU. As a result of the mass dog vaccination campaigns, human rabies cases due to dog-mediated rabies decreased from 60 in 1990 to 0 in 2000. The number of rabies cases in dogs decreased from 3,049 in 1990 to 70 cases last year.

Endocarditis due to vancomycin-resistant Enterococcus raffinosus successfully treated with linezolid: case report and review of literature.

Enterococcus raffinosus is scarcely found in clinical samples and even less frequently as etiologic agent of endocarditis. We are herein presenting one case of mitral prosthetic-valve endocarditis in a 77-y-o male due to a vancomycin-resistant Enterococcus raffinosus isolate, successfully treated with 6 weeks of linezolid, and a two-year follow up.

Molecular identification of Echinococcus granulosus genotypes (G1 and G7) isolated from pigs in Mexico.

With the aim of genotyping Echinococcus granulosus cysts found in Mexican livestock, we collected hydatid cysts from the livers and lungs of pigs in slaughterhouses in the state of Morelos, Central Region of Mexico. DNA was extracted from the parasites and examined by polymerase chain reaction (PCR) of rDNA internal transcribed spacer 1 (ITS1-PCR), Eg9-PCR, Eg16-PCR, and PCR-restriction fragment length polymorphism (PCR-RFLP). In addition, fragments of the genes coding for mitochondrial cytochrome c oxidase subunit 1 (CO1) and NADH dehydrogenase 1 (ND1) were sequenced. Two different genotypes of E. granulosus were unequivocally identified, the common sheep genotype, G1, and the common pig genotype, G7. The G1 genotype of E. granulosus has not been previously demonstrated in Mexico. Because of its recognized infectivity in humans, G1 genotype is a direct threat to human health and its presence in Mexico is consequently of immediate public health importance and epidemiological relevance.

Prevalence of Escherichia coli O157 in cattle and swine in central Mexico.

Escherichia coli O157:H7 is a foodborne pathogenic bacterium that can reside undetected in the gastrointestinal tract of cattle because colonization by this bacterium is asymptomatic. Recent research has indicated that swine can carry and transmit this pathogen as well. The development of more advanced and sensitive detection techniques has improved the limit of detection and increased sensitivity for this important pathogen. This study was undertaken to determine the prevalence of E. coli O157 in cattle and swine in Mexico with the more sensitive detection technique of immunomagnetic bead separation. Samples (n = 60 per farm) were taken from four cattle and four swine farms (n = 240 cattle samples, n = 240 swine samples) located throughout central Mexico in October 2001. The prevalence of E. coli O157 was found to be only 1.25% on cattle farms and 2.1% on swine farms. The prevalence in cattle in this study is lower than that reported in the United States and could be related to the lower reported prevalence of E. coli O157 in humans in Mexico. However, further research is needed to verify prevalence throughout other regions of Mexico, as well as prevalence during other seasons of the year.

[Duchenne and Becker muscular dystrophy in Chile]. / Distrofia muscular de Duchenne y Becker en Chile.

Duchenne muscular dystrophy is one of the best known forms of muscular dystrophy. The incidence in different countries varies from 130 to 390 per million male live births. Becker variety may be considered a mild form of Duchenne dystrophy, with an incidence 10 times lower. A sex linked recessive inheritance is involved in both forms, the affected gene is placed at locus X21. The incidence of both forms in Chile is similar to that reported worldwide, and has been increasing since 1950. Increased CK and LDH levels are confirmed in patients, and overall, they are also higher in female carriers. However only 26% of carriers have increased CK levels and 21% increased LDH levels, compared to normal subjects. Electromyograms show myopathic characteristics in all carrier women. The scope of a prospective clinical, genetic and epidemiologic study currently underway is discussed.