Multi-drug resistant Staphylococcus aureus isolated from emergency ward of an Iranian hospital

Purpose: To study the prevalence of resistant strains of Staphylococcus aureus isolated from surfaces, beds and various equipment of an Iranian hospital emergency ward. Methods: Two hundred swab samples were collected from the surfaces, beds, trolleys, surgical equipment and diagnostic medical devices in emergency ward. Samples were cultured and those that were S. aureus-positive were confirmed using polymerase chain reaction (PCR). Antimicrobial resistance pattern was analyzed using disk diffusion method. Results: Nine of 200 samples (4.5 %) collected were positive for S. aureus. Surfaces (8.8 %), beds (5 %) and trolleys (5 %) were the most commonly contaminated. S. aureus isolates exhibited varying levels of resistance against antibiotics with the following being the highest: tetracycline (88.8 %), penicillin (88.8 %) and ampicillin (77.7 %). The prevalence of resistance against methicillin, oxacillin and azithromycin were 44.4, 33.3 and 33.3 %, respectively. There was no pattern of resistance against imipenem. Conclusion: Efficient disinfection of surfaces, beds, trolleys and surgical instruments should be performed periodically to reduce colonization of resistant strains of S. aureus in various areas of emergency health care centers.

Positive biocompatibility of nanocrystalline glass-like carbon thin films

The interest in carbon nanomaterials with high transparency and electrical conductivity has grown within the last decade in view of a wide variety of applications, including biocompatible sensors, diagnostic devices and bioelectronic implants. The aim of this work is to test the biocompatibility of particular nanometer-thin nanocrystalline glass-like carbon films (NGLC), a disordered structure of graphene flakes joined by carbon matrix (Romero et al., 2016). We used a cell line (SN4741) from substantia nigra dopaminergic cells derived from transgenic mouse embryo cells (Son et al., 1999). Some cells were cultured on top of NGLC films (5, 20 and 80 nm) and other with NGLC nanoflakes (approx. 5-10 mm2) in increasing concentrations: 1, 5, 10, 20 and 50 μg/ml, during 24 h, 3 days and 7 days. Cells growing in normal conditions were defined under culture with DMEM supplemented with 10% FCS, Glucose (0,6%), penicillin-streptomycin (50U/ml) and L-glutamine (2mM) at 5%CO2 humidified atmosphere. Nanoflakes were resuspended in DMEM at the stock concentration (2 g/l). The experiments were conducted in 96 well plates (Corning) using 2500 cells per well. For MTT analysis, the manufacturer recommendations were followed (Roche, MTT kit assay): a positive control with a 10% Triton X-100 treatments (15 minutes) and a negative control without neither Triton X-100 nor NGLC. As apoptosis/necrosis assay we used LIVE/DEAD® Viability/Cytotoxicity Assay Kit (Invitrogen). In a separate experiment, cells were cultured on top of the NGLC films for 7 days. Primary antibodies: anti-synaptophysin (SYP, clone SY38, Chemicon) and goat anti-GIRK2 (G-protein-regulated inward-rectifier potassium channel 2 protein) (Abcom) following protocol for immunofluorescence. WB for proteins detection performed with a polyclonal anti-rabbit proliferating cell nuclear antigen (PCNA). Results demonstrated the biocompatibility with different concentration of NGLC varying the degree of survival from a low concentration (1 mg/ml) in the first 24 h to high concentrations (20-50 g/ml) after 7 days as it is corroborated by the PCNA analysis. Cells cultured on top of the film showed after 7 days axonal-like alignment and edge orientation as well as net-like images. Neuronal functionality was demonstrated to a certain extent through the analysis of coexistence between SYP and GIRK2. In conclusion, this nanomaterial could offer a powerful platform for biomedical applications such as neural tissue engineering

Utilización de antimicrobianos en las infecciones odontogénicas en niños y adolescentes: análisis farmacocinético/farmacodinámico (PK/PD)

El objetivo de este estudio es evaluar la eficacia de los tratamientos más utilizados en infecciones odontogénicas en niños y adolescentes aplicando criterios farmacocinéticos/farmacodinámicos (PK/PD). Se han simulado las curvas de concentración plasmática libre-tiempo a partir de parámetros farmacocinéticos medios de amoxicilina, amoxicilina-ácido clavulánico, cefuroxima axetilo, espiramicina, clindamicina, azitromicina y metronidazol. Para los antibióticos con actividad dependiente del tiempo, se ha calculado el tiempo durante el cual las concentraciones permanecen por encima de la concentración inhibitoria mínima (CIM90) de los microorganismos (T>CIM). Para los antimicrobianos con actividad dependiente de la concentración, se ha calculado el cociente entre el área bajo la curva y la CIM90 (ABC/CIM90). Con amoxicilina-ácido clavulánico (80 mg/kg/día) se han obtenido índices de eficacia adecuados frente a los microorganismos estudiados (T > CIM > 40%), excepto paraVeillonella spp. Clindamicina (40 mg/kg/día) también ha presentado índices PK/PD adecuados frente a la mayoría de los patógenos, excepto Lactobacillus, Actinobacillus actinomycetemcomitans, Peptostreptococcus resistente a penicilina y Eikenella corrodens. Con dosis altas de amoxicilina los resultados no han sido satisfactorios frente a varias especies bacterianas. Con azitromicina y metronidazol no se han alcanzado valores adecuados frente a la mayoría de patógenos (ABC/CIM90 < 25). En conclusión, el tratamiento empírico más adecuado en infecciones odontogénicas en niños y adolescentes es amoxicilina-ácido clavulánico en altas dosis de amoxicilina, aunque se puede utilizar como alternativa clindamicina. Sería conveniente confirmar estos resultados mediante ensayos clínicos, para cuyo diseño y evaluación podría ser de gran utilidad la aplicación de estudios PK/PD.