I’m a Professor at CIAD Mazatlan working in the Bacteriology and Microbial Genomic Laboratories. My principal lines of research are: virulence mechanisms of bacteria of aquatic, Pathology of shrimp and fish, isolation and Pathogenesis of aquatic bacteria. Since 2013 I’m the head research in Mexico about the pathogenesis of vibrios causing AHPND in shrimp. My major scientific publications are about diseases of shrimp and fish, their virulence factors and pathogen characterization, including two new shrimp diseases (BRS and AHPND) and three new bacteria pathogenic to tilapia.
1 Departamento de Genética y Bioestadística, Facultad de Medicina Veterinaria y Zootecnia, Univer... more 1 Departamento de Genética y Bioestadística, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Ciudad Universitaria, Circuito Exterior, Coyoacán, CDMX, Mexico montaldo@unam.mx (Corresponding autor) 2 Departamento de Producción Agrícola y Animal, Universidad Autónoma Metropolitana, Unidad Xochimilco, Coyoacán, CDMX, Mexico 3 Departamento El Hombre y su Ambiente, Universidad Autónoma Metropolitana, Unidad Xochimilco, Coyoacán, CDMX, Mexico Maricultura del Pacífico, Mazatlán, Sinaloa, Mexico. 5 Centro de Investigación en Alimentación y Desarrollo, A.C. Unidad Mazatlán en Acuicultura y Manejo Ambiental, Mazatlán, Sinaloa, Mexico
Vibrio parahaemolyticusstrains have been identified as the causative agent of acute hepatopancrea... more Vibrio parahaemolyticusstrains have been identified as the causative agent of acute hepatopancreas necrosis disease (VpAHPND+) in shrimp. In the present work, a highly virulent (M0904) and less virulent (M0607) strain ofVpAHPND+ were used in experimental infections ofPenaeus vannamei. Throughout the experiment, histopathological analyses were conducted on shrimp tissues, and samples from the bottom (B) and water column (WC) of each aquarium were taken to estimate bacterial growth. The first deaths of shrimp challenged withVpM0904 occurred 4 h post-infection (hpi), reached 50% mortality at 17 hpi, and showed more acute pathological progression associated with AHPND despite both strains having similar bacterial densities from 0-4 hpi. The first deaths of shrimp inoculated withVpM0607 occurred at 13 hpi, a difference of 9 h. These shrimps displayed reduction of reserve vacuoles in R and B cells of the hepatopancreas, and reached 50% mortality at 27 hpi. As bacterial growth in the WC an...
Vibrio parahaemolyticus (Vp) is the etiological agent of the acute hepatopancreatic necrosis dise... more Vibrio parahaemolyticus (Vp) is the etiological agent of the acute hepatopancreatic necrosis disease (AHPND) in Penaeus vannamei shrimp. Vp possesses a 63–70 kb conjugative plasmid that encodes the binary toxin PirAvp/PirBvp. The 250 kDa PirABvp complex was purified by affinity chromatography with galactose-sepharose 4B and on a stroma from glutaraldehyde-fixed rat erythrocytes column, as a heterotetramer of PirAvp and PirBvp subunits. In addition, recombinant pirB (rPirBvp) and pirA (rPirAvp) were obtained. The homogeneity of the purified protein was determined by SDS-PAGE analysis, and the yield of protein was 488 ng/100 μg of total protein of extracellular products. The PirABvp complex and the rPirBvp showed hemagglutinating activity toward rat erythrocytes. The rPirAvp showed no hemagglutinating capacity toward the animal red cells tested. Among different mono and disaccharides tested, only GalNH2 and GlcNH2 were able to inhibit hemagglutination of the PirABvp complex and the rP...
To examine the pathogenicity of Vibrio strains, several doses of Vibrio harveyi (CAIM 1622 and CA... more To examine the pathogenicity of Vibrio strains, several doses of Vibrio harveyi (CAIM 1622 and CAIM 1508), Vibrio ponticus (CAIM 1751) and Vibrio anguillarum (CAIM 8) were used to challenge Pacific white snook Centropomus viridis Lockington, 1877 juveniles, and survival, gross signs and histological lesions were observed. Susceptibility of pathogenic vibrios CAIM 1508 and CAIM 1751 to antibiotics used in aquaculture was also evaluated. The growth ability of the tested strains was not related to their pathogenicity. One of the V. harveyi strains (CAIM 1508) was the most virulent, causing per-acute septicaemia in C. viridis even at a low dose (1.4 × 104 CFU g-1). Although the V. ponticus strain (CAIM 1751) was less virulent, this is the first report of it as a pathogen of white snook. Fish challenged with V. ponticus displayed external, generalized haemorrhaging. Necrosis of the digestive tract and intravascular haemosiderosis were the most remarkable histological lesions in fish challenged with both strains. Multifocal necrosis of the internal organs and bacterial masses was also observed. The lowest minimum inhibitory concentration of the pathogenic strains (CAIM 1508 and CAIM 1751) was calculated for enrofloxacin (20 and 10 µg ml-1, respectively), and both bacteria were resistant to amoxicillin, ampicillin and trimethoprim-sulfamethoxazole.
Between August and December 2013, the offshore cages of a commercial marine farm culturing red dr... more Between August and December 2013, the offshore cages of a commercial marine farm culturing red drum Sciaenops ocellatus in Campeche Bay Mexico were affected by an outbreak of an ulcerative granulomatous disease with up to 70% cumulative mortality. Thirty‐one adults displaying open ulcers on the skin were submitted for diagnosis. At necropsy, multiple white‐yellowish nodules (0.1–0.5 cm in diameter) were present in all internal organs, where the kidney and the spleen were the most severely affected. Histopathology evinced typical systemic granulomatous formations. Gram and Ziehl–Neelsen stains on tissue imprints, bacterial swabs and tissue sections revealed Gram‐positive, acid‐fast, branching beaded long rod filamentous bacteria. Tissue samples resulted positive for nocardiosis with a Nocardia genus‐specific nested PCR. Definite identification at the species level and taxonomic positioning of the fastidious pathogen were achieved through a specific Nocardia seriolae PCR and by sequen...
1 Departamento de Genética y Bioestadística, Facultad de Medicina Veterinaria y Zootecnia, Univer... more 1 Departamento de Genética y Bioestadística, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Ciudad Universitaria, Circuito Exterior, Coyoacán, CDMX, Mexico montaldo@unam.mx (Corresponding autor) 2 Departamento de Producción Agrícola y Animal, Universidad Autónoma Metropolitana, Unidad Xochimilco, Coyoacán, CDMX, Mexico 3 Departamento El Hombre y su Ambiente, Universidad Autónoma Metropolitana, Unidad Xochimilco, Coyoacán, CDMX, Mexico Maricultura del Pacífico, Mazatlán, Sinaloa, Mexico. 5 Centro de Investigación en Alimentación y Desarrollo, A.C. Unidad Mazatlán en Acuicultura y Manejo Ambiental, Mazatlán, Sinaloa, Mexico
Vibrio parahaemolyticusstrains have been identified as the causative agent of acute hepatopancrea... more Vibrio parahaemolyticusstrains have been identified as the causative agent of acute hepatopancreas necrosis disease (VpAHPND+) in shrimp. In the present work, a highly virulent (M0904) and less virulent (M0607) strain ofVpAHPND+ were used in experimental infections ofPenaeus vannamei. Throughout the experiment, histopathological analyses were conducted on shrimp tissues, and samples from the bottom (B) and water column (WC) of each aquarium were taken to estimate bacterial growth. The first deaths of shrimp challenged withVpM0904 occurred 4 h post-infection (hpi), reached 50% mortality at 17 hpi, and showed more acute pathological progression associated with AHPND despite both strains having similar bacterial densities from 0-4 hpi. The first deaths of shrimp inoculated withVpM0607 occurred at 13 hpi, a difference of 9 h. These shrimps displayed reduction of reserve vacuoles in R and B cells of the hepatopancreas, and reached 50% mortality at 27 hpi. As bacterial growth in the WC an...
Vibrio parahaemolyticus (Vp) is the etiological agent of the acute hepatopancreatic necrosis dise... more Vibrio parahaemolyticus (Vp) is the etiological agent of the acute hepatopancreatic necrosis disease (AHPND) in Penaeus vannamei shrimp. Vp possesses a 63–70 kb conjugative plasmid that encodes the binary toxin PirAvp/PirBvp. The 250 kDa PirABvp complex was purified by affinity chromatography with galactose-sepharose 4B and on a stroma from glutaraldehyde-fixed rat erythrocytes column, as a heterotetramer of PirAvp and PirBvp subunits. In addition, recombinant pirB (rPirBvp) and pirA (rPirAvp) were obtained. The homogeneity of the purified protein was determined by SDS-PAGE analysis, and the yield of protein was 488 ng/100 μg of total protein of extracellular products. The PirABvp complex and the rPirBvp showed hemagglutinating activity toward rat erythrocytes. The rPirAvp showed no hemagglutinating capacity toward the animal red cells tested. Among different mono and disaccharides tested, only GalNH2 and GlcNH2 were able to inhibit hemagglutination of the PirABvp complex and the rP...
To examine the pathogenicity of Vibrio strains, several doses of Vibrio harveyi (CAIM 1622 and CA... more To examine the pathogenicity of Vibrio strains, several doses of Vibrio harveyi (CAIM 1622 and CAIM 1508), Vibrio ponticus (CAIM 1751) and Vibrio anguillarum (CAIM 8) were used to challenge Pacific white snook Centropomus viridis Lockington, 1877 juveniles, and survival, gross signs and histological lesions were observed. Susceptibility of pathogenic vibrios CAIM 1508 and CAIM 1751 to antibiotics used in aquaculture was also evaluated. The growth ability of the tested strains was not related to their pathogenicity. One of the V. harveyi strains (CAIM 1508) was the most virulent, causing per-acute septicaemia in C. viridis even at a low dose (1.4 × 104 CFU g-1). Although the V. ponticus strain (CAIM 1751) was less virulent, this is the first report of it as a pathogen of white snook. Fish challenged with V. ponticus displayed external, generalized haemorrhaging. Necrosis of the digestive tract and intravascular haemosiderosis were the most remarkable histological lesions in fish challenged with both strains. Multifocal necrosis of the internal organs and bacterial masses was also observed. The lowest minimum inhibitory concentration of the pathogenic strains (CAIM 1508 and CAIM 1751) was calculated for enrofloxacin (20 and 10 µg ml-1, respectively), and both bacteria were resistant to amoxicillin, ampicillin and trimethoprim-sulfamethoxazole.
Between August and December 2013, the offshore cages of a commercial marine farm culturing red dr... more Between August and December 2013, the offshore cages of a commercial marine farm culturing red drum Sciaenops ocellatus in Campeche Bay Mexico were affected by an outbreak of an ulcerative granulomatous disease with up to 70% cumulative mortality. Thirty‐one adults displaying open ulcers on the skin were submitted for diagnosis. At necropsy, multiple white‐yellowish nodules (0.1–0.5 cm in diameter) were present in all internal organs, where the kidney and the spleen were the most severely affected. Histopathology evinced typical systemic granulomatous formations. Gram and Ziehl–Neelsen stains on tissue imprints, bacterial swabs and tissue sections revealed Gram‐positive, acid‐fast, branching beaded long rod filamentous bacteria. Tissue samples resulted positive for nocardiosis with a Nocardia genus‐specific nested PCR. Definite identification at the species level and taxonomic positioning of the fastidious pathogen were achieved through a specific Nocardia seriolae PCR and by sequen...
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