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1.
Int J Food Microbiol ; 426: 110890, 2024 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-39241546

RESUMEN

Salmonella enterica subsp. enterica serovar Typhimurium variant 4,[5],12:i:- (referred to as S. 4,[5],12:i:-) has emerged rapidly as the predominant Salmonella serovar in pigs, often associated with the acquisition of antibiotic resistance (ABR) and heavy metal resistance (HMR) genes. Our study analysed 78 strains of S. 4,[5],12:i:- (n = 57) and S. Typhimurium (n = 21), collected from 1999 to 2021, to investigate the evolution of mobile genetic elements (MGEs) containing HMR and ABR genes. Five MGEs harbouring HMR genes were identified: pUO-STVR2, pSTM45, pUO-STmRV1, SGI-4 and MREL. Among the strains, 91.23 % (52/57) of S. 4,[5],12:i:- carried at least one of these elements, compared to only 14.29 % (3/21) of S. Typhimurium. Since 2008, S. 4,[5],12:i:- have shifted from predominantly carrying pUO-STmRV1 to the emergence of SGI-4 and MREL, reducing ABR genes, reflecting the European Union ban on the use of antibiotics as feed additives. Increased resistance to copper and silver in S. 4,[5],12:i:-, conferred by SGI-4 and MREL, reflected that their acquisition was linked to the ongoing use of heavy metals in food-animal production. However, strains carrying SGI-4 and MREL still exhibit multidrug resistance, emphasising the need for targeted interventions to mitigate multidrug-resistant Salmonella spread in veterinary and public health settings.

2.
Appl Environ Microbiol ; 90(5): e0026424, 2024 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-38695519

RESUMEN

The emergence of foodborne Salmonella strains carrying antimicrobial resistance (AMR) in mobile genetic elements (MGE) is a significant public health threat in a One Health context requiring continuous surveillance. Resistance to ciprofloxacin and cephalosporins is of particular concern. Since pigs are a relevant source of foodborne Salmonella for human beings, we studied transmissible AMR genes and MGE in a collection of 83 strains showing 9 different serovars and 15 patterns of multidrug resistant (MDR) previously isolated from pigs raised in the conventional breeding system of Northern Spain. All isolates were susceptible to ciprofloxacin and three isolates carried blaCMY-2 or blaCTX-M-9 genes responsible for cefotaxime resistance. Filter mating experiments showed that the two plasmids carrying blaCTX-M-9 were conjugative while that carrying blaCMY-2 was self-transmissible by transformation. Whole-genome sequencing and comparative analyses were performed on the isolates and plasmids. The IncC plasmid pSB109, carrying blaCMY-2, was similar to one found in S. Reading from cattle, indicating potential horizontal transfer between serovars and animal sources. The IncHI2 plasmids pSH102 in S. Heidelberg and pSTM45 in S. Typhimurium ST34, carrying blaCTX-M-9, shared similar backbones and two novel "complex class 1 integrons" containing different AMR and heavy metal genes. Our findings emphasize the importance of sequencing techniques to identify emerging AMR regions in conjugative and stable plasmids from livestock production. The presence of MGE carrying clinically relevant AMR genes raises public health concerns, requiring monitoring to mitigate the emergence of bacteria carrying AMR genes and subsequent spread through animals and food.IMPORTANCEThe emergence of foodborne Salmonella strains carrying antimicrobial resistance (AMR) in mobile genetic elements (MGE) is a significant public health threat in a One Health context. Since pigs are a relevant source of foodborne Salmonella for humans, in this study, we investigate different aspects of AMR in a collection of 83 Salmonella showing nine different serovars and 15 patterns of multidrug resistant (MDR) isolated from pigs raised in the conventional breeding system. Our findings emphasize the importance of sequencing techniques to identify emerging AMR regions in conjugative and stable plasmids from livestock production. The presence of MGE carrying clinically relevant AMR genes raises public health concerns, requiring monitoring to mitigate the emergence of bacteria carrying AMR genes and subsequent spread through animals and food.


Asunto(s)
Antibacterianos , Farmacorresistencia Bacteriana Múltiple , Secuencias Repetitivas Esparcidas , Plásmidos , Salmonella , Animales , Porcinos/microbiología , Plásmidos/genética , Salmonella/genética , Salmonella/efectos de los fármacos , Salmonella/aislamiento & purificación , Farmacorresistencia Bacteriana Múltiple/genética , Antibacterianos/farmacología , Humanos , Resistencia a las Cefalosporinas/genética , Salmonelosis Animal/microbiología , España , Enfermedades de los Porcinos/microbiología , Cefalosporinas/farmacología , Transferencia de Gen Horizontal
3.
Int J Food Microbiol ; 419: 110753, 2024 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-38797020

RESUMEN

Salmonella enterica subsp. enterica serovar Typhimurium variant 4,[5],12:i:- (so called S. 4,[5],12:i:-) has rapidly become one of the most prevalent serovars in humans in Europe, with clinical cases associated with foodborne from pork products. The mechanisms, genetic basis and biofilms relevance by which S. 4,[5],12:i:- maintains and spreads its presence in pigs remain unclear. In this study, we examined the genetic basis of biofilm production in 78 strains of S. 4,[5],12:i:- (n = 57) and S. Typhimurium (n = 21), from human gastroenteritis, food products and asymptomatic pigs. The former showed a lower Specific Biofilm Formation index (SBF) and distant phylogenetic clades, suggesting that the ability to form biofilms is not a crucial adaptation for the S. 4,[5],12:i:- emerging success in pigs. However, using a pan-Genome-Wide Association Study (pan-GWAS) we identified genetic determinants of biofilm formation, revealing 167 common orthologous groups and genes associated with the SBF. The analysis of annotated sequences highlighted specific genetic deletions in three chromosomal regions of S. 4,[5],12:i:- correlating with SBF values: i) the complete fimbrial operon stbABCDE widely recognized as the most critical factor involved in Salmonella adherence; ii) the hxlA, hlxB, and pgiA genes, which expression in S. Typhimurium is induced in the tonsils during swine infection, and iii) the entire iroA locus related to the characteristic deletion of the second-phase flagellar genomic region in S. 4,[5],12:i:-. Consequently, we further investigated the role of the iro-genes on biofilm by constructing S. Typhimurium deletion mutants in iroBCDE and iroN. While iroBCDE showed no significant impact, iroN clearly contributed to S. Typhimurium biofilm formation. In conclusion, the pan-GWAS approach allowed us to uncover complex interactions between genetic and phenotypic factors influencing biofilm formation in S. 4,[5],12:i:- and S. Typhimurium.


Asunto(s)
Proteínas Bacterianas , Biopelículas , Estudio de Asociación del Genoma Completo , Salmonella typhimurium , Biopelículas/crecimiento & desarrollo , Salmonella typhimurium/genética , Salmonella typhimurium/metabolismo , Animales , Porcinos , Humanos , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Hierro/metabolismo , Filogenia , Salmonelosis Animal/microbiología , Infecciones por Salmonella/microbiología , Gastroenteritis/microbiología , Serogrupo
4.
Methods Find Exp Clin Pharmacol ; 8(11): 649-53, 1986 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-3807466

RESUMEN

There is increasing evidence suggesting that endogenous opioid peptides play a role both in temperature regulation and in the etiopathology of seizures. We have studied the effects of the opioid antagonist naloxone on hyperthermia-induced seizures in unrestrained 15 day old rat pups. Saline injected control animals exposed to an ambient temperature of 40 degrees C for one hr showed a gradual increase in body temperature reaching a maximum of 42 degrees C at 50 min of exposure; at this time, all animals had convulsions and 86% died. Animals pre-treated with 10 mg/kg naloxone reached a maximum core temperature of 41 degrees C after 60 min at 40 degrees C and no convulsions or deaths were observed. When animals were exposed for 60 min to a 27 degrees C environment, saline controls maintained their normal body temperature throughout the experiment, while 5 mg/kg naloxone produced a marked hyperthermic effect. These experiments suggest that endogenous opioids may play a role in both temperature adaptation and hyperthermia-induced seizures in the rat pup.


Asunto(s)
Naloxona/farmacología , Convulsiones Febriles/prevención & control , Adaptación Fisiológica/efectos de los fármacos , Animales , Modelos Animales de Enfermedad , Calor , Ratas , Ratas Endogámicas
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