Pseudomonas aeruginosa is an opportunistic pathogen with a high capacity to adapt to different factors. The aim of this study is to analyze the pathogenicity in P. aeruginosa strains and their resistance to heavy metals and antibiotics, in agricultural soil of the state of Tamaulipas, Mexico. Susceptibility to 16 antibiotics was tested using the Kirby-Bauer method (CLSI). Eight virulence factors (FV) and six genes associated with heavy metal resistance were detected by PCR. As a result, P. aeruginosa was detected in 55% of the samples. The eight virulence factors were identified in ≥80% of the strains. The strains showed some level of resistance to only three antibiotics: 32.8% to ticarcillin, 40.8% to ticarcillin/clavulanic acid and 2.4% to aztreonam. The most frequent heavy metal resistance genes were arsC (92.8%) and copA (90.4%). However, copB and arsB genes were also identified in a percentage greater than 80%, and the least frequent genes were merA in 14.4% and czcA in 7.2%. Although P. aeruginosa strains showed a high percentage of factor virulence (potential ability to cause infections), their high levels of susceptibility to antibiotics lead to the assumption that infections are easily curable.

Background/Objectives: Antibiotic-resistant strains have been reported in aquatic ecosystems, with varying prevalence and resistance patterns by region. In Tamaulipas, Mexico, little information has been generated on this topic, making it difficult to estimate their potential risk to environmental and human health. Therefore, the objective of this study was to evaluate the presence and virulence of antibiotic-resistant strains of Pseudomonas aeruginosa in environmental water from Tamaulipas, Mexico. Methods: One hundred water samples were collected from different water bodies in Tamaulipas to identify P. aeruginosa by PCR and MALDI-TOF, virulence gene detection, antimicrobial susceptibility testing, and detection class 1 integrons. Results: In this study, 109 P. aeruginosa strains were isolated. Eight virulence genes were identified in 47.7% to 80.7% of the strains, with the rhlAB gene being the most frequent. The strains showed resistance or intermedia resistance to 10 of the 16 antibiotics tested, in a range of resistance values 0.9–66.2%. In total, 100% (109/109) were susceptible to ceftazidime (CAZ), gentamicin (GM), amikacin (AN), netilmicin (NET), tobramycin (NN) and norfloxacin (NOR), and 65.7% were resistant to ticarcillin/clavulanic acid and 53.5% to ticarcillin; the resistance to the remaining antibiotics was between 19.4% and 0.9%. The class 1 integron was not identified in any of the strains analyzed. Conclusions:P. aeruginosa in environmental waters of Tamaulipas showed potential to cause infections and low rates of resistance to most of the antibiotics tested. However, 20% were resistant to one of the most common treatments, which could pose a risk to public health.

La bacteria Azospirillum brasilense ha sido estudiada por asociarse a la estimulación de crecimiento de plantas por producción de auxinas, especialmente del ácido indol acético, además de la fijación biológica de nitrógeno. El análisis de genomas se emplea para generar una matriz de huella genómica y con ellos construir un árbol para distinguir las diferencias entre especies de este género. El presente análisis se realizó con el método de la huella genómica virtual empleando el programa VAMPhyRE. Se diseñaron sondas para detectar 19 nucleótidos y con los resultados obtenidos se generó una matriz de huella genómica a partir de la cual se construyó un árbol genómico de mínima evolución el cual reveló las relaciones filogenómicas entre las especies del género resaltando que la especie A brasilense está separada en un clado perfectamente diferenciado de las otras especies del grupo. Así mismo, el análisis permitió detectar que el genoma de A brasilense este compuesto de 19.284 genes, equivalentes a 16 % de los genes anotados y conforman el core genome de las cepas analizadas. El 27 % son genes medianamente conservados. Esta es una evidencia de la gran variabilidad genómica de la especie. Además, se generó un gráfico del genoma de la especie. Además, empleando el programa PROKKA y el método de huella genómica virtual se creó una matriz de distancias que generó un árbol filogenómico de mínima evolución, sin raíz, en forma radial mostrando que todas las cepas de A brasilense están alojadas en un mismo clado y separadas de las otras especies de este género.