The Changing Epidemiology and Antimicrobial Susceptibility of Staphylococcus aureus Isolated from Blood Cultures in a University Hospital from Argentina.

Staphylococcus aureus bacteremia (SAB) is one of the most common serious bacterial infections worldwide. In this study, we demonstrated changes in SAB epidemiology in an Argentinean University Hospital during an 8-year period (2009-2016). A total of 326 S. aureus clinical isolates were recovered in three periods: P1: 2009-2010, P2: 2012-2014, and P3: 2015-2016. Among these, 127 were methicillin-resistant S. aureus (MRSA) and were characterized by phenotypic and molecular methods. We hereby report a significant decline in multiple drug resistance among MRSA isolates associated with an increase in SCCmec IV between the three periods. A diversity of MRSA-IV clones (mainly ST30-MRSA-IV, ST5-MRSA-IV, and ST8-MRSA-IV) replaced between 2009 and 2016 the previous prevalent MRSA clone causing bloodstream infections at this hospital (ST5-MRSA-I). MRSA population structure continued to diversify between P2 and P3. Notably, ST8-MRSA-IV-t008 related to USA300 was first detected during P2, and ST8-MRSA-IV together with ST30-MRSA-IV related to the Southwest Pacific clone were the more prevalent MRSA genotypes circulating during P3.

[Vibrio vulnificus infection of the skin and soft parts. Communication of a case diagnosed in Argentina]. / Infección de piel y partes blandas por Vibrio vulnificus. Comunicación de un caso diagnosticado en Argentina.

Vibrio vulnificus is one of the most virulent Vibrio species known. It is a bacterium with universal distribution. The first case registered in Uruguay occurred in 2001 and, since then, several infections have occurred per year. Recently, in this country, V. vulnificus was responsible for a fatal soft tissue infection. Although no cases of human infection with this species have been reported in Argentina, researchers have recently identified V. vulnificus in samples associated with microplankton in the Rio Negro estuary. We present the case of a severe skin and soft tissue infection by V. vulnificus from an open wound in a patient in contact with a marine aquatic environment on the coast of the River Plate, in Uruguay. Isolation of vibrios from wound specimens can cause rapidly progressing tissue damage, particularly V. vulnificus which has a high mortality rate without early and appropriate intervention. In our case, the rapid identification of the microorganism allowed us to support the empirical treatment used, which a good clinical evolution.

Vibrio vulnificus es una de las especies de Vibrio más virulentas que se conocen. Es una bacteria de distribución universal. El primer caso registrado en Uruguay se produjo en 2001, y desde entonces ocurren varias infecciones por año. Recientemente, en ese país, V. vulnificus fue responsable de una infección de partes blandas de curso letal. Aunque no han sido comunicados casos de infección humana por esta especie en Argentina, se ha identificado recientemente Vibrio vulnificus en muestras asociadas con microplancton en el estuario del Río Negro. Presentamos el caso de una infección grave de piel y partes blandas por V. vulnificus a partir de una herida abierta en un paciente en contacto con medio acuático marino en la costa de Uruguay del Río de la Plata. El aislamiento de vibrios en muestras de heridas puede causar un daño en los tejidos con rápida progresión, en particular V. vulnificus, que tiene una alta mortalidad sin la precoz y apropiada intervención. En nuestro caso, la rápida identificación del microorganismo permitió avalar el tratamiento empírico utilizado, con una buena evolución clínica.

Infección de piel y partes blandas por Vibrio vulnificus. Comunicación de un caso diagnosticado en Argentina / Vibrio vulnificus infection of the skin and soft parts. Communication of a case diagnosed in Argentina

Resumen Vibrio vulnificus es una de las especies de Vibrio más virulentas que se conocen. Es una bacteria de distribución universal. El primer caso registrado en Uruguay se produjo en 2001, y desde entonces ocurren varias infecciones por año. Recientemente, en ese país, V. vulnificus fue responsable de una infección de partes blandas de curso letal. Aunque no han sido comunicados casos de infección humana por esta especie en Argentina, se ha identificado recientemente Vibrio vulnificus en muestras asociadas con microplancton en el estuario del Río Negro. Presentamos el caso de una infección grave de piel y partes blandas por V. vulnificus a partir de una herida abierta en un paciente en contacto con medio acuático marino en la costa de Uruguay del Río de la Plata. El aislamiento de vibrios en muestras de heridas puede causar un daño en los tejidos con rápida progresión, en particular V. vulnificus, que tiene una alta mortalidad sin la precoz y apropiada intervención. En nuestro caso, la rápida identificación del microorganismo permitió avalar el tratamiento empírico utilizado, con una buena evolución clínica.

Abstract Vibrio vulnificus is one of the most virulent Vibrio species known. It is a bacterium with universal distribution. The first case registered in Uruguay occurred in 2001 and, since then, several infections have occurred per year. Recently, in this country, V. vulnificus was responsible for a fatal soft tissue infection. Although no cases of human infection with this species have been reported in Argentina, researchers have recently identified V. vulnificus in samples associated with microplankton in the Rio Negro estuary. We present the case of a severe skin and soft tissue infection by V. vulnificus from an open wound in a patient in contact with a marine aquatic environment on the coast of the River Plate, in Uruguay. Isolation of vibrios from wound specimens can cause rapidly progressing tissue damage, particularly V. vulnificus which has a high mortality rate without early and appropriate intervention. In our case, the rapid identification of the microorganism allowed us to support the empirical treatment used, which a good clinical evolution.

Evaluation of sperm integrin α5ß1 as a potential marker of fertility in humans.

Sperm selection for assisted reproduction techniques is generally based on basic parameters, while key aspects of sperm competence and its journey from the deposition site to the fertilization site are overlooked. Consequently, identifying molecular markers in spermatozoa that can efficiently predict the fertility of a semen sample could be of great interest, particularly in cases of idiopathic male infertility. When spermatozoa reach the female reproductive tract, it provides to them the cellular and molecular microenvironment needed to acquire fertilizing ability. In this sense, considering the role that integrin α5ß1 of spermatozoa plays in reproduction-related events, we investigated the correlation between the subcellular localization of sperm integrin α5ß1 and early embryo development outcome after in vitro fertilization (IVF) procedures in human. Twenty-four semen samples from normozoospermic men and metaphase II (MII) oocytes from healthy women aged under 38 years, from couples who underwent IVF cycles, were used in this work. Sperm α5ß1 localization was evaluated by immunofluorescence assay using an antibody against integrin α5 subunit. Integrin α5ß1 was mainly localized in the sperm acrosomal region (45.33±7.89%) or the equatorial segment (30.12±7.43%). The early embryo development rate (data obtained from the Fertility Center) correlated positively with the localization of α5ß1 in the acrosomal region (number of usable embryos / inseminated oocytes: ρ = 0.75; p<0.01 and number of usable embryos/total number of two pronuclear zygotes: ρ = 0.80; p<0.01). However, this correlation was not significant when the equatorial segment mark was evaluated. In addition, human sperm released from co-culture with bovine oviductal epithelial cells (BOEC) showed a significant enrichment in the acrosomal localization pattern of α5ß1 compared to those sperm that were not co-cultured with BOEC (85.20±5.35% vs 35.00±17.09%, respectively, p<0.05). In conclusion, the evaluation of sperm integrin α5ß1 immunolocalization could be a useful tool to select sperm with fertilizing ability from human semen samples before IVF procedures.

Photosensitization of bovine serum albumin by pterin: a mechanistic study.

Pterins, heterocyclic compounds widespread in biological systems, are able to photoinduce oxidation of DNA and its components. In the present study, we have investigated the photosensitizing properties of pterin (Ptr), the parent compound of oxidized pterins, using bovine serum albumin (BSA) as target. Aqueous solutions of BSA were exposed to UV-A irradiation (350nm) in the presence of Ptr, under various experimental conditions. The photosensitized processes were followed by UV/vis spectrophotometry, an enzymatic method for H2O2 determination and electrophoresis (SDS-PAGE). We present data that demonstrate unequivocally that BSA is damaged by Ptr. Although association between Ptr and the protein was evidenced by steady-state and time-resolved fluorescence measurements, the photosensitized damage takes place via a purely dynamic mechanism, which involves an electron transfer from BSA to the triplet excited state of Ptr, formed after UV-A excitation.