Genomic epidemiology of Staphylococcus aureus isolated from bloodstream infections in South America during 2019 supports regional surveillance.

Staphylococcus aureus remains one of the leading causes of infections worldwide and a common cause of bacteraemia. However, studies documenting the epidemiology of S. aureus in South America using genomics are scarce. We hereby report on the largest genomic epidemiology study to date of both methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) in South America, conducted by the StaphNET-SA network. We characterised 404 genomes recovered from a prospective observational study of S. aureus bacteraemia in 58 hospitals from Argentina, Bolivia, Brazil, Paraguay and Uruguay between April and October 2019. We show that a minority of S. aureus isolates are phenotypically multi-drug resistant (5.2%), but more than a quarter are resistant to macrolide-lincosamide-streptogramin B (MLSb). MSSA were more genetically diverse than MRSA. Lower rates of associated antimicrobial resistance in community-associated(CA)-MRSA versus hospital-associated (HA)-MRSA were found in association with three S. aureus genotypes dominating the MRSA population: CC30-MRSA-IVc-t019-lukS/F-PV+, CC5-MRSA-IV-t002-lukS/F-PV- and CC8-MRSA-IVc-t008-lukS/F-PV+-COMER+. These are historically from a CA origin, carry on average fewer antimicrobial resistance determinants, and often lack key virulence genes. Surprisingly, CC398-MSSA-t1451-lukS/F-PV- related to the CC398 human-associated lineage is widely disseminated throughout the region, and is described here for the first time as the most prevalent MSSA lineage in South America. Moreover, CC398 strains carrying ermT (largely responsible for the MLSb resistance rates of MSSA strains: inducible iMLSb phenotype) and sh_fabI (related to triclosan resistance) were recovered from both CA and HA origin. The frequency of MRSA and MSSA lineages differed between countries but the most prevalent S. aureus genotypes are high-risk clones widely distributed in the South American region without a clear country-specific phylogeographical structure. Therefore, our findings underline the need for continuous genomic surveillance by regional networks such as StaphNET-SA. This article contains data hosted by Microreact.

Biochemical changes in certain enzymes of Lysapsus limellium (Anura: Hylidae) exposed to chlorpyrifos.

Different enzyme biomarkers (AChE: acetylcholinesterase, CbE: carboxylesterase, GST: glutathione-S-transferase, CAT: catalase) were measured in digestive tissues of Lysapsus limellum frogs collected from a rice field (RF: chlorpyriphos sprayed by aircraft) and a non-contaminated area (RS: reference site), immediately (24h) and 168 h after aerial spraying with chlorpyrifos (CPF). CPF degradation was also searched in water samples collected from RF and RS, and found that insecticide concentration was reduced to≈6.78% of the original concentration in RF at 168 h. A significant reduction of AChE and CbE activities was detected in L. limellum from RF in stomach and liver at 24 and 168 h, and in intestine only at 24h, with respect to RS individuals. CAT activity decreased in intestine of L. limellum from RF 24h and 168 h after exposure to CPF, whereas GST decreased in that tissue only at 24h. In stomach and liver, a decrease was observed only at 168 h in both CAT and GST. The use of biomarkers (AChE, CbE, GST, and CAT) provides different lines of evidences for ecotoxicological risk assessment of wild frog populations at sites contaminated with pesticides.

Beneficios de incorporar un simbiótico a la dieta de adultos mayores con infecciones recurrentes / Benefits of adding symbiotic food to the diet of elderly people with recurrent infections

El propósito de este trabajo fue estudiar la evolución clínica de un grupo de adultos mayores, proclives a padecer infecciones bacterianas principalmente de las vías respiratorias, al adicionar a su dieta un alimento simbiótico con Lactobacillus casei, Lactobacillus acidophillus y fructanos y, además, correlacionar los resultados obtenidos con modificaciones en los parámetros inmunológicos medidos. Se incluyeron 90 pacientes adultos mayores de 65 años, todos con antecedentes de infecciones bacterianas recurrentes de las vías respiratorias. Cada individuo suplementó su dieta habitual con una dosis diaria del simbiótico SanCor Bio con fructanos. La administración se realizó durante los meses de época invernal. Se realizó un seguimiento clínico, se hizo recuento de Lactobacillus spp en materia fecal, se cuantificaron subpoblaciones linfocitarias CD4 y CD8 y se evaluó la activación de monocitos en sangre periférica. Se observó disminución de los cuadros virales (gripales) y ausencia de infecciones bacterianas de vías respiratorias; además, aumentó el número de Lactobacillus spp en materia fecal y se estimuló la respuesta inmune principalmente inespecífica. Esto sugiere que dicho simbiótico puede ser utilizado como terapia preventiva en grupos vulnerables a infecciones y con depleciones del sistema inmunológico.

The aim of this work was to study the clinical evolution of a group of elderly people who had a tendency to suffer from bacterial infections, mainly of the respiratory tract, after having added food with Lactobacillus casei, Lactobacillus acidophilus and fructans to their diet, and then to correlate the results obtained with alterations in immunological parameters previously set. Ninety patients who were older than 65 and had a background of recurrent bacterial infections in their respiratory tract were included in this study. Their daily diet was supplemented with a dose of Sancor Bio during winter months in 2007. A clinical analysis was carried out, Lactobacillus spp in faeces were counted, CD4 and CD8 lymphocytes were quantified and the activation of monocytes in peripheral blood was evaluated. In conclusion, the administration of this symbiotic food proved to be biochemical and clinically effective, showing to be a good colony of the intestinal mucose, promoting the principally unspecific immune response, everything correlated with clinical information. All this suggests that this food can be used asa preventive therapy in groups of people who are vulnerable to infections and who have immunological system depletions.