Preliminary assessment of VIS-NIR-SWIR spectroscopy with a portable instrument for the detection of Staphylococcus aureus biofilms on surfaces

6 p.Bacterial biofilms constitute a major source of sanitary problems and economic losses in the food industry. Indeed, biofilm removal may require intense mechanical cleaning procedures or very high concentrations of disinfectants or both, which can be damaging to the environment and human health. This study assessed the efficacy of a technique based on spectroscopy in the visible, near-infrared, and short-wavelength infrared range for the quick detection of biofilms formed on polystyrene by the pathogenic bacterium Staphylococcus aureus. To do that, biofilms corresponding to three S. aureus strains, which differed in biofilm-forming ability and composition of the extracellular matrix, were allowed to develop for 5 or 24 h, representing an active formation stage and mature biofilms, respectively. Spectral analysis of the samples, corresponding to three biological replicates of each condition, was then performed by using a portable device. The results of these experiments showed that partial least squares discriminant analysis of the spectral profile could discriminate between surfaces containing attached bacterial biomass and non-inoculated ones. In this model, the two first principal components accounted for 39 and 19% of the variance and the estimated error rate stabilized after four components. Cross-validation accuracy of this assessment was 100%. This work lays the foundation for subsequent development of a spectroscopy-based protocol that allows biofilm detection on food industrial surfacesS

Modelling the spatial risk of malaria through probability distribution of Anopheles maculipennis s.l. and imported cases

Malaria remains one of the most important infectious diseases globally due to its high incidence and mortality rates. The influx of infected cases from endemic to non-endemic malaria regions like Europe has resulted in a public health concern over sporadic local outbreaks. This is facilitated by the continued presence of competent Anopheles vectors in non-endemic countries. We modelled the potential distribution of the main malaria vector across Spain using the ensemble of eight modelling techniques based on environmental parameters and the Anopheles maculipennis s.l. presence/absence data collected from 2000 to 2020. We then combined this map with the number of imported malaria cases in each municipality to detect the geographic hot spots with a higher risk of local malaria transmission. The malaria vector occurred preferentially in irrigated lands characterized by warm climate conditions and moderate annual precipitation. Some areas surrounding irrigated lands in northern Spain (e.g. Zaragoza, Logroño), mainland areas (e.g. Madrid, Toledo) and in the South (e.g. Huelva), presented a significant likelihood of A. maculipennis s.l. occurrence, with a large overlap with the presence of imported cases of malaria. While the risk of malaria re-emergence in Spain is low, it is not evenly distributed throughout the country. The four recorded local cases of mosquito-borne transmission occurred in areas with a high overlap of imported cases and mosquito presence. Integrating mosquito distribution with human incidence cases provides an effective tool for the quantification of large-scale geographic variation in transmission risk and pinpointing priority areas for targeted surveillance and prevention

Efectos de la dispersión de alimento sobre la elección y los patrones de exploración

Una variable poco estudiada en el área de forrajeo y elección de parches es la distribución del alimento. Dos parches con similar densidad de alimento pero distinta distribución implican diferentes tiempos de búsqueda y, en consecuencia, diferente exposición a posibles predadores. Se estudió el efecto de la dispersión de alimento sobre la elección, exploración y explotación de parche. Se expuso a un grupo de ratas a un instrumento con una zona de elección y dos parches topográficamente iguales y con la misma cantidad de alimento, pero diferente dispersión: alimento concentrado en un solo lugar vs alimento disperso en ocho puntos. Los animales permanecieron durante más tiempo en el parche con alimento concentrado, mientras que en el parche disperso realizaron visitas breves y exhaustivas respecto al vaciado. Los animales desarrollaron patrones de exploración tópicos para cada una de las zonas. Se sugiere que los animales establecieron la zona de elección y el parche concentrado como zonas seguras de exploración