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RESUMEN Introducción: para lograr el adecuado y precoz diagnóstico de la infección en pie diabético, es necesario la obtención de una muestra bacteriológica de calidad para la identificación del germen causal. Objetivo: identificar posibles relaciones entre los resultados obtenidos, en el cultivo realizado mediante hisopado superficial versus el obtenido mediante biopsia de los tejidos profundos en la infección del pie diabético. Materiales y métodos: se realizó un estudio explicativo observacional, longitudinal, prospectivo en el Servicio Provincial de Angiología y Cirugía Vascular del Hospital Provincial Clínico Quirúrgico Universitario "Comandante Faustino Pérez", durante un periodo de 3 años desde enero del 2016 hasta diciembre del 2018. Una selección muestral no probabilística determinó una muestra constituida por 138 extremidades en 132 pacientes con diagnóstico clínico de pie diabético infectado, que requirieron cirugía para desbridamiento de la lesión. Aceptaron ser incluidos en la investigación y para el aislamiento del germen causal fueron empleados ambos métodos de cultivo: hisopado superficial y biopsia de los tejidos profundos. Resultados: el promedio de microorganismos aislados se incrementó en relación con la severidad de la infección del pie diabético, con mayor incremento en el aislamiento hecho por el hisopado superficial. El hisopado superficial posee pobre correlación con los gérmenes aislados mediante el cultivo de la biopsia de los tejidos profundos. Conclusiones: las muestras deben ser obtenidas preferentemente por curetaje. En el diagnóstico de la infección del pie diabético es de gran utilidad, por su rapidez y concordancia con los resultados del cultivo, efectuar siempre una tinción de Gram a partir del mismo sitio (AU).

ABSTRACT Introduction: to arrive to an adequate and precocious diagnosis of the diabetic foot infection, it is necessary to obtain a qualitative bacteriological sample to identify the causing germ. Objective: to identify possible relationships between the results obtained both, in the culture made through superficial swab and the culture obtained from deep tissues biopsy in the diabetic foot infection. Materials and methods: a prospective, longitudinal, observational, explicative study was carried out in the Provincial Service of Angiology and Vascular Surgery of Provincial University Clinical Surgical Hospital "Comandante Faustino Pérez", in a period of three years, from January 2016 to December 2018. A non-probabilistic sampling choose a sample of 138 lower limbs in 132 patients with clinical diagnosis of infected diabetic foot, who required surgery for lesion debridement. They gave their consent to be included in the research; for the isolation of the casual germ were used both culture methods, superficial swab and deep tissues biopsy. Results: the average of isolated microorganism increased in relation to the severity of the diabetic food infection, with higher increase in the isolation obtained by superficial swab. The superficial swab shows poor correlation with the germ isolates by the culture the deep tissue biopsy. Conclusions: the samples should be gathered preferably by curettage. In the diagnosis of the diabetic foot infection, it is very useful, due to its speed and concordance with the culture results, to make always a Gram staining beginning from the same place (AU).

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The development of multi-species biofilms in chronic wounds is a serious health problem that primarily generates strong resistance mechanisms to antimicrobial therapy. The use of silver nanoparticles (AgNPs) as a broad-spectrum antimicrobial agent has been studied previously. However, their cytotoxic effects limit its use within the medical area. The purpose of this study was to evaluate the anti-biofilm capacity of chitosan gel formulations loaded with AgNPs, using silver sulfadiazine (SSD) as a standard treatment, on strains of clinical isolates, as well as their cytotoxic effect on human primary fibroblasts. Multi-species biofilm of Staphylococcus aureus oxacillin resistant (MRSA) and Pseudomonas aeruginosa obtained from a patient with chronic wound infection were carried out using a standard Drip Flow Reactor (DFR) under conditions that mimic the flow of nutrients in the human skin. Anti-biofilm activity of chitosan gels and SSD showed a log-reduction of 6.0 for MRSA when chitosan gel with AgNPs at a concentration of 100 ppm was used, however it was necessary to increase the concentration of the chitosan gel with AgNPs to 1000 ppm to get a log-reduction of 3.3, while the SSD showed a total reduction of both bacteria in comparison with the negative control. The biocompatibility evaluation on primary fibroblasts showed better results when the chitosan gels with AgNPs were tested even in the high concentration, in contrast with SSD, which killed all the primary fibroblasts. In conclusion, chitosan gel formulations loaded with AgNPs effectively prevent the formation of biofilm and kill bacteria in established biofilm, which suggest that chitosan gels with AgNPs could be used for prevention and treatment of infections in chronic wounds. The statistic significance of the biocompatibility of chitosan gel formulations loaded with AgNPs represents an advance; however further research and development are necessary to translate this technology into therapeutic and preventive strategies.

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