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1.
Int J Food Microbiol ; 344: 109109, 2021 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-33677191

RESUMO

The objective of the present study was to characterize Salmonella enterica serovar Infantis isolated from chicken meat determining their clonal relationships with S. Infantis isolated from children with diarrhea. Fifteen meat-recovered S. Infantis were analyzed. Susceptibility levels to 14 antibacterial agents, the presence of ESBL and that of inducible plasmid-mediated AmpC (i-pAmpC) were determined by phenotypical methods. The presence of ESBL and pAmpC was confirmed by PCR, and detected ESBL-encoding genes were sequenced and their transferability tested by conjugation. The presence of gyrA mutations as well as Class 1 integrons was determined by PCR. Clonal relationships were established by REP-PCR and RAPD. In addition, 25 clinical isolates of S. Infantis were included in clonality studies. All meat-recovered S. Infantis were MDR, showing resistance to ampicillin, nitrofurans and quinolones, while none was resistant to azithromycin, ceftazidime or imipenem. ESBL (blaCTX-M-65) and i-pAmpC (blaDHA) were detected in 2 and 5 isolates respectively (in one case concomitantly), with blaCTX-M-65 being transferable through conjugation. In addition, 1 isolate presented a blaSHV gene. All isolates presented D87Y at GyrA, nalidixic acid active efflux pump and a Class 1 integron of ~1000 bp (aadA1). Clonal analysis showed that all isolates were related. Further they were identical to MDR blaCTX-M-65-producing S. Infantis isolates causing children diarrhea in Lima. The dissemination of MDR blaCTX-M-65-producing S. Infantis between marketed meat and children highlights a public health problem which needs be controlled at livestock level.


Assuntos
Proteínas de Bactérias/genética , Carne/microbiologia , Intoxicação Alimentar por Salmonella/transmissão , Salmonelose Animal/transmissão , Salmonella enterica/genética , beta-Lactamases/genética , Animais , Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Galinhas/microbiologia , Criança , Humanos , Integrons/genética , Plasmídeos/genética , Técnica de Amplificação ao Acaso de DNA Polimórfico , Intoxicação Alimentar por Salmonella/microbiologia , Salmonelose Animal/microbiologia , Salmonella enterica/efeitos dos fármacos , Salmonella enterica/isolamento & purificação , Sorogrupo , beta-Lactamases/metabolismo
2.
Int J Food Microbiol ; 340: 109042, 2021 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-33461002

RESUMO

The development of antimicrobial resistance in foodborne pathogens is a growing public health concern. This study was undertaken to determine the antimicrobial susceptibility of Salmonella enterica subspecies enterica isolated from the Australian commercial egg layer industry. S. enterica subspecies enterica (n=307) isolated from Australian commercial layer flock environments (2015-2018) were obtained from reference, research and State Government laboratories from six Australian states. All Salmonella isolates were serotyped. Antimicrobial susceptibility testing (AST) for 16 antimicrobial agents was performed by broth microdilution. Antimicrobial resistance genes and sequence types (STs) were identified in significant isolates by whole genome sequencing (WGS). Three main serotypes were detected, S. Typhimurium (n=61, 19.9%), S. Senftenburg (n=45, 14.7%) and S. Agona (n=37, 12.1%). AST showed 293/307 (95.4%) isolates were susceptible to all tested antimicrobial agents and all isolates were susceptible to amoxicillin-clavulanate, azithromycin, ceftiofur, ceftriaxone, ciprofloxacin, colistin, florfenicol, gentamicin, kanamycin and trimethoprim-sulfamethoxazole. Low levels of non-susceptibility were observed to streptomycin (2.3%, n=7), sulfisoxazole (2.0%, n=6), chloramphenicol (1.3%, n=4) and tetracycline (1.0%, n=3). Very low levels of non-susceptibility were observed to ampicillin (2/307; 0.7%) and cefoxitin (2/307; 0.7%). Two isolates (S. Havana and S. Montevideo), exhibited multidrug-resistant phenotypes to streptomycin, sulfisoxazole and tetracycline and possessed corresponding antimicrobial resistance genes (aadA4, aac(6')-Iaa, sul1, tetB). One S. Typhimurium isolate was resistant to ampicillin and tetracycline, and possessed both tetA and blaTEM-1B. WGS also identified these isolates as belonging to ST4 (S. Montevideo), ST578 (S. Havana) and ST19 (S. Typhimurium). The absence of resistance to highest priority critically important antimicrobials as well as the extremely low level of AMR generally among Australian commercial egg layer Salmonella isolates likely reflect Australia's conservative antimicrobial registration policy in food-producing animals and low rates of antimicrobial use within the industry.


Assuntos
Antibacterianos/farmacologia , Galinhas/microbiologia , Farmacorresistência Bacteriana , Abrigo para Animais , Aves Domésticas/microbiologia , Salmonella enterica/efeitos dos fármacos , Animais , Austrália , Ciprofloxacino/farmacologia , Farmacorresistência Bacteriana/genética , Farmacorresistência Bacteriana Múltipla/genética , Genoma Bacteriano , Testes de Sensibilidade Microbiana , Salmonella enterica/isolamento & purificação , Sorogrupo , Sequenciamento Completo do Genoma
3.
Appl Environ Microbiol ; 87(6)2021 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-33361364

RESUMO

Antimicrobial-resistant pathogens display significant public health threats by causing difficulties in clinical treatment of bacterial infection. Antimicrobial resistance (AMR) is transmissible between bacteria, significantly increasing the appearance of antimicrobial-resistant pathogens and aggravating the AMR problem. In this work, the dissemination dynamics of AMR from invading multidrug-resistant (MDR) Escherichia coli to a community of pathogenic Salmonella enterica was investigated using a continuous-culture device, and the behaviors of dissemination dynamics under different levels of antibiotic stress were investigated. Three MDR E. coli invasion events were analyzed in this work: MDR E. coli-S. enterica cocolonization, MDR E. coli invasion after antibiotic treatment of S. enterica, and MDR E. coli invasion before antibiotic treatment of S. enterica It was found that both horizontal gene transfer (HGT) and vertical gene transfer (VGT) play significant roles in AMR dissemination, although different processes contribute differently under different circumstances, that environmental levels of antibiotics promote AMR dissemination by enhancing HGT rather than leading to selective advantage for resistant bacteria, and that early invasion of MDR E. coli completely and quickly sabotages the effectiveness of antibiotic treatment. These findings contribute to understanding the drivers of AMR dissemination under different antibiotic stresses, the detrimental impact of environmental tetracycline contamination, and the danger of nosocomial presence and dissemination of MDR nonpathogens.IMPORTANCE Antimicrobial resistance poses a grave threat to public health and reduces the effectiveness of antimicrobial drugs in treating bacterial infections. Antimicrobial resistance is transmissible, either by horizontal gene transfer between bacteria or by vertical gene transfer following inheritance of genetic traits. The dissemination dynamics and behaviors of this threat, however, have not been rigorously investigated. In this work, with a continuous-culture device, we studied antimicrobial resistance dissemination processes by simulating antimicrobial-resistant Escherichia coli invasion to a pathogenic Salmonella enterica community. Using this novel tool, we provide evidence on the drivers of antimicrobial resistance dissemination, on the detrimental impact of environmental antibiotic contamination, and on the danger of antimicrobial resistance in hospitals, even if what harbors the antimicrobial resistance is not a pathogen. This work furthers our understanding of antimicrobial resistance and its dissemination between bacteria and of antibiotic therapy, our most powerful tool against bacterial infection.


Assuntos
Farmacorresistência Bacteriana Múltipla/genética , Escherichia coli/genética , Salmonella enterica/genética , Antibacterianos/farmacologia , Técnicas Bacteriológicas , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Transferência Genética Horizontal , Interações Microbianas , Testes de Sensibilidade Microbiana , Filogenia , Salmonella enterica/efeitos dos fármacos , Salmonella enterica/crescimento & desenvolvimento , Tetraciclina/farmacologia
4.
Methods Mol Biol ; 2182: 127-139, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32894492

RESUMO

Salmonella enterica is able to establish robust adherent communities called biofilms that allow for long-term colonization of both biotic and abiotic surfaces. These biofilm communities pose a significant challenge to successful eradication of the bacteria from contaminated surfaces and the infected host, as entry into the biofilm phenotype confers the bacterial population with tolerance to a variety of environmental and therapeutic insults to which it would otherwise be susceptible. The identification of antimicrobial strategies that specifically target the Salmonella biofilm state is therefore of great importance in order to both prevent and treat biofilm-mediated disease. Here, we provide detailed methods for the in vitro cultivation of Salmonella biofilms that can easily be scaled up for use in high-throughput screening of candidate anti-biofilm agents. These assays may also be utilized to further characterize the inhibitory and/or disruptive capabilities of lead anti-biofilm agents, as well as to identify combination treatments that demonstrate enhanced anti-biofilm effects. Furthermore, the assays may be slightly modified (e.g., optimal growth conditions) to evaluate other bacterial genera.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Salmonella enterica/efeitos dos fármacos
6.
Int J Food Microbiol ; 335: 108859, 2020 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-32947147

RESUMO

In this study, 205 Salmonella enterica serovar Corvallis strains were obtained from humans and foods from Guangdong, Guangxi, and Shanghai in China from 2009 to 2017 to assess drug resistance and molecular epidemiology. These isolates displayed high rates of resistance to sulfisoxazole (94.15%) and tetracycline (77.56%). Surprisingly, the rate of resistance to ciprofloxacin reached 21.46%. Moreover, 63.9% of the strains displayed multidrug resistance. Detection of quinolone genes showed that 97.56% of the strains had single mutations (T57S) in parC. The plasmid-mediated quinolone resistance (PMQR) genes qnrS, aac(6')-Ib-cr, and qnrB, were also detected. The extended spectrum ß-lactamase (ESBLS) gene that was most common among the isolates was blaTEM-1 (18.05%). These S. Corvallis isolates are the first to date, that have been reported to possess blaCTX-M-55 or blaNDM-5. Additionally, 95.61% of isolates were biofilm producers. The streptomycin resistance rate was higher in strong biofilm producers (87.50%) than in moderate (37.93%) and weak (26.49%) biofilm producers. Pulsed-field gel electrophoresis (PFGE) showed that some strains from different sources had the same genotype. These isolates may be transmitted to humans through food and therefore the monitoring of these isolates should be strengthened in China.


Assuntos
Farmacorresistência Bacteriana Múltipla/genética , Quinolonas/farmacologia , Salmonella enterica/efeitos dos fármacos , Salmonella enterica/genética , beta-Lactamases/genética , Animais , Antibacterianos/farmacologia , Biofilmes/crescimento & desenvolvimento , Galinhas/microbiologia , China , Eletroforese em Gel de Campo Pulsado , Microbiologia de Alimentos , Humanos , Testes de Sensibilidade Microbiana , Plasmídeos/genética , Prevalência , Salmonella enterica/isolamento & purificação , Sorogrupo
7.
PLoS Pathog ; 16(7): e1008700, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32687537

RESUMO

With antibiotic resistance rates on the rise, it is critical to understand how microbial species interactions influence the evolution of resistance. In obligate mutualisms, the survival of any one species (regardless of its intrinsic resistance) is contingent on the resistance of its cross-feeding partners. This sets the community antibiotic sensitivity at that of the 'weakest link' species. In this study, we tested the hypothesis that weakest link dynamics in an obligate cross-feeding relationship would limit the extent and mechanisms of antibiotic resistance evolution. We experimentally evolved an obligate co-culture and monoculture controls along gradients of two different antibiotics. We measured the rate at which each treatment increased antibiotic resistance, and sequenced terminal populations to question whether mutations differed between mono- and co-cultures. In both rifampicin and ampicillin treatments, we observed that resistance evolved more slowly in obligate co-cultures of E. coli and S. enterica than in monocultures. While we observed similar mechanisms of resistance arising under rifampicin selection, under ampicillin selection different resistance mechanisms arose in co-cultures and monocultures. In particular, mutations in an essential cell division protein, ftsI, arose in S. enterica only in co-culture. A simple mathematical model demonstrated that reliance on a partner is sufficient to slow the rate of adaptation, and can change the distribution of adaptive mutations that are acquired. Our results demonstrate that cooperative metabolic interactions can be an important modulator of resistance evolution in microbial communities.


Assuntos
Adaptação Fisiológica/efeitos dos fármacos , Resistência Microbiana a Medicamentos/fisiologia , Escherichia coli/fisiologia , Interações Microbianas/fisiologia , Salmonella enterica/fisiologia , Adaptação Fisiológica/genética , Ampicilina/farmacologia , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Técnicas de Cocultura , Escherichia coli/efeitos dos fármacos , Interações Microbianas/efeitos dos fármacos , Modelos Teóricos , Mutação , Rifampina/farmacologia , Salmonella enterica/efeitos dos fármacos
8.
PLoS One ; 15(7): e0235641, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32614888

RESUMO

We sequenced 25 isolates of phenotypically multidrug-resistant Salmonella Indiana (n = 11), Typhimurium (n = 8), and Enteritidis (n = 6) using both MinION long-read [SQK-LSK109 and flow cell (R9.4.1)] and MiSeq short-read (Nextera XT and MiSeq Reagent Kit v2) sequencing technologies to determine the advantages of each approach in terms of the characteristics of genome structure, antimicrobial resistance (AMR), virulence potential, whole-genome phylogeny, and pan-genome. The MinION reads were base-called in real-time using MinKnow 3.4.8 integrated with Guppy 3.0.7. The long-read-only assembly, Illumina-only assembly, and hybrid assembly pipelines of Unicycler 0.4.8 were used to generate the MinION, MiSeq, and hybrid assemblies, respectively. The MinION assemblies were highly contiguous compared to the MiSeq assemblies but lacked accuracy, a deficiency that was mitigated by adding the MiSeq short reads through the Unicycler hybrid assembly which corrected erroneous single nucleotide polymorphisms (SNPs). The MinION assemblies provided similar predictions of AMR and virulence potential compared to the MiSeq and hybrid assemblies, although they produced more total false negatives of AMR genotypes, primarily due to failure in identifying tetracycline resistance genes in 11 of the 19 MinION assemblies of tetracycline-resistant isolates. The MinION assemblies displayed a large genetic distance from their corresponding MiSeq and hybrid assemblies on the whole-genome phylogenetic tree, indicating that the lower read accuracy of MinION sequencing caused incorrect clustering. The pan-genome of the MinION assemblies contained significantly more accessory genes and less core genes compared to the MiSeq and hybrid assemblies, suggesting that although these assemblies were more contiguous, their sequencing errors reduced accurate genome annotations. Our research demonstrates that MinION sequencing by itself provides an efficient assessment of the genome structure, antimicrobial resistance, and virulence potential of Salmonella; however, it is not sufficient for whole-genome phylogenetic and pan-genome analyses. MinION in combination with MiSeq facilitated the most accurate genomic analyses.


Assuntos
Farmacorresistência Bacteriana Múltipla/genética , Genoma Bacteriano , Salmonella enterica/genética , Sequenciamento Completo do Genoma/métodos , Antibacterianos/farmacologia , Genótipo , Testes de Sensibilidade Microbiana , Fenótipo , Filogenia , Plasmídeos/genética , Plasmídeos/metabolismo , Mutação Puntual , Salmonella enterica/classificação , Salmonella enterica/efeitos dos fármacos , Salmonella enterica/patogenicidade , Salmonella enteritidis/classificação , Salmonella enteritidis/efeitos dos fármacos , Salmonella enteritidis/genética , Salmonella enteritidis/patogenicidade , Salmonella typhimurium/classificação , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/genética , Salmonella typhimurium/patogenicidade , Virulência
9.
Int J Food Microbiol ; 333: 108790, 2020 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-32693316

RESUMO

Salmonella, one of the most important foodborne pathogens, can be the cause of bacterial food-borne illness and is commonly associated with the consumption of retail meat. Multidrug-resistant Salmonella isolates with high adaptability, have been responsible for many foodborne disease outbreaks. Here we present an investigation on the contamination and the antimicrobial resistance of Salmonella in retail meat obtained from supermarkets and from open markets in Guangxi, China. From the years 2009 to 2016, a total of 604 Salmonella isolates were recovered from a total of 3340 meat samples including 797 beef, 911 pork, 942 chicken and 690 duck, representing 18.08% of the samples tested. Pork was the most contaminated meat. Salmonella was detected in 322 samples from supermarkets and the positive rate of 21.03% was higher than that of 15.70% in 284 samples from open markets (P<0.05). The prevalence of Salmonella in retail meat in the summer and fall months: June (2015, 40.63%), October (2012, 34.6%; 2016, 43.75%) was higher than in other seasons of the year. One hundred and twenty-seven serotypes were identified among the 604 Salmonella enterica isolates, and S. Derby (28.48%), S. Agona (9.77%), S. London (4.97%) and S. Enteritidis (4.47%) were the most common serotypes. Tests of susceptibility to 21 antimicrobial agents showed that 87.58% of the isolates were resistant to at least one antimicrobial, and 57.79% exhibited multidrug resistance (MDR), as they were resistant to at least three antimicrobials. The presence of most of the antimicrobial-resistant genes tested was consistent with the resistant phenotypes found. Among all the antimicrobial resistant genes (ARGs) examined in this study, blaTEM-1, aadA1, cmlA, tetA, sul1 and sul2 were the most prevalent resistant genes in the multidrug resistant isolates. Our findings show that there was a trend that the Salmonella contamination in retail meat had increased and isolates showed an MDR phenotype and that the MDR had become more and more serious. Twenty-one isolates of S. Agona were randomly analyzed by using the enterobacterial repetitive intergenic consensus sequence PCR (ERIC-PCR) and six different types were found, indicating the existence of cross-contamination in the food market. The results indicate that the hazard analysis of the critical control points (HACCP) system for the whole food chain of retail meat should be further analyzed and improved.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Carne/microbiologia , Salmonella enterica/efeitos dos fármacos , Animais , Bovinos , Galinhas/microbiologia , China , Patos , Doenças Transmitidas por Alimentos/microbiologia , Testes de Sensibilidade Microbiana , Prevalência , Salmonella enterica/genética , Salmonella enterica/isolamento & purificação , Suínos
10.
Food Chem ; 328: 127131, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32485586

RESUMO

Carvacrol (CAR) is a natural bioactive compound with antioxidant and antimicrobial activity that is present in essential oils. The application of CAR in food preservation is hampered by its high volatility, low solubility in water, and susceptibility to light, heat and oxygen degradation. Polylactide (PLA) is an FDA-approved polymer derived from renewable resources. Controlled release of CAR from PLA nanoparticles (NPs) could improve its antimicrobial efficacy and storage. In this study, negatively charged CAR-NPs and positively charged polyethylenimine (PEI)-coated CAR-(PEI)NPs were formulated by nanoprecipitation methods and characterised by dynamic light scattering, electron microscopy, encapsulation efficiency, and drug loading capacity. The positively charged (PEI)NPs enhanced the in vitro antimicrobial activity of CAR against Escherichia coli, Listeria monocytogenes, Salmonella enterica and Staphylococcus aureus. Bacterial uptake, evaporation tests, release studies and NP stability after storage were assessed to provide evidence supporting CAR-(PEI)NPs as a potential nanocarrier for further development in food preservation.


Assuntos
Antibacterianos/farmacologia , Cimenos/farmacologia , Nanopartículas/química , Poliésteres/química , Antibacterianos/química , Cimenos/química , Cimenos/farmacocinética , Portadores de Fármacos/química , Escherichia coli/efeitos dos fármacos , Microbiologia de Alimentos , Listeria monocytogenes , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Polietilenoimina/química , Salmonella enterica/efeitos dos fármacos , Solubilidade , Staphylococcus aureus/efeitos dos fármacos
11.
Microb Cell Fact ; 19(1): 98, 2020 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-32366243

RESUMO

BACKGROUND: An increasing rate of antibiotic resistance among Gram-negative bacterial pathogens has created an urgent need to discover novel therapeutic agents to combat infectious diseases. Use of bacteriocins as therapeutic agents has immense potential due to their high potency and mode of action different from that of conventional antibiotics. RESULTS: In this study, a novel bacteriocin E20c of molecular weight 6.5 kDa was purified and characterized from the probiotic strain of Enterococcus hirae. E20c had bactericidal activities against several multidrug resistant (MDR) Gram-negative bacterial pathogens. Flow cytometry and scanning electron microscopy studies showed that it killed the Salmonella enterica cells by forming ion-permeable channels in the cell membrane leading to enhanced cell membrane permeability. Further, checkerboard titrations showed that E20c had synergistic interaction with antibiotics such as ampicillin, penicillin, ceftriaxone, and ciprofloxacin against a ciprofloxacin- and penicillin-resistant strain of S. enterica. CONCLUSION: Thus, this study shows the broad spectrum antimicrobial activity of novel enterocin E20c against various MDR pathogens. Further, it highlights the importance of bacteriocins in lowering the minimum inhibitory concentrations of conventional antibiotics when used in combination.


Assuntos
Antibacterianos/farmacologia , Bacteriocinas/farmacologia , Ciprofloxacino/farmacologia , Salmonella enterica/efeitos dos fármacos , beta-Lactamas/farmacologia , Bacteriocinas/isolamento & purificação , Hidrocarbonetos Aromáticos com Pontes/isolamento & purificação , Hidrocarbonetos Aromáticos com Pontes/farmacologia , Membrana Celular/efeitos dos fármacos , Permeabilidade da Membrana Celular/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla , Sinergismo Farmacológico , Streptococcus faecium ATCC 9790/química , Streptococcus faecium ATCC 9790/metabolismo , Bactérias Gram-Negativas/efeitos dos fármacos , Testes de Sensibilidade Microbiana
12.
Int J Food Microbiol ; 328: 108660, 2020 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-32450393

RESUMO

Salmonella (S.) Infantis is currently the most common serovar in broilers and boiler meat in the European Union. In the field, eradication of S. Infantis in affected poultry flocks is considered extremely difficult. Despite stringent cleaning and disinfection measures between the placement of flocks, recurrent infections are often reported. So far, the efficacy of disinfectants on S. Infantis has rarely been studied. Therefore, in the present in-vitro study the bacteriostatic and bactericidal efficacy of ten commercial disinfectants were tested against seven S. Infantis field isolates. Combinations of aldehyde and quarternary ammonium were the active compounds of five, peroxygen of three, cresol and alkylamines of one disinfectant, respectively. Investigations were performed according to standard protocols and regulations. Different concentrations of disinfectants were used to test the bacteriostatic efficacy. Different temperatures and low and high protein exposures were applied as variables to investigate the bactericidal efficacy. Following neutralization of the disinfectants an additional incubation step was introduced to investigate the revitalisation potential of S. Infantis. The bacteriostatic efficacy could be assessed for seven disinfectants. For three disinfectants a bacteriostatic effect was observed when the recommended concentration was used, whereas with four disinfectants only increased concentrations led to this effect. The bactericidal efficacy was not influenced by temperature, whereas high protein exposure decreased the efficacy of nine disinfectants. Furthermore, reactivation of S. Infantis was revealed after application of disinfectants for the majority of products. Interestingly, the strain of S. Infantis influenced the efficacy of the disinfectants. Overall, products based on aldehydes and quarternary ammonium compounds proved most efficient, followed by peroxgen, cresol and alkylamines.


Assuntos
Antibacterianos/farmacologia , Desinfetantes/farmacologia , Doenças das Aves Domésticas/prevenção & controle , Salmonelose Animal/prevenção & controle , Salmonella enterica/efeitos dos fármacos , Aldeídos/farmacologia , Compostos de Amônio/farmacologia , Animais , Galinhas/microbiologia , Cresóis/farmacologia , Microbiologia de Alimentos , Carne/microbiologia , Aves Domésticas/microbiologia , Doenças das Aves Domésticas/microbiologia , Salmonelose Animal/microbiologia , Salmonella enterica/classificação , Salmonella enterica/isolamento & purificação
13.
Food Microbiol ; 90: 103470, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32336351

RESUMO

Particulates of harvest debris are common in tomato packinghouse dump tanks, but their role in food safety is unclear. In this study we investigated the survival of Salmonella enterica and the shifts in relative abundance of culturable mesophilic aerobic bacteria (cMAB) as impacted by particulate size and interaction with chlorine treatment. Particulates suspended in grape tomato wash water spanned a wide size range, but the largest contribution came from particles of 3-20 µm. Filtration of wash water through 330 µm, applied after 100 mg/L free chlorine (FC) wash, reduced surviving cMAB by 98%. The combination of filtration (at 330 µm or smaller pore sizes) and chlorinated wash also altered the cMAB community, with the survivors shifting toward Gram-positive and spore producers (in both lab-simulated and industrial conditions). When tomatoes and harvest debris inoculated with differentially tagged Salmonella were washed in 100 mg/L FC for 1 min followed by filtration, only cells originating from harvest debris survived, with 85 and 93% of the surviving cells associated with particulates larger than 330 and 63 µm, respectively. This suggests that particulates suspended in wash water can protect Salmonella cells from chlorine action, and serve as a vector for cross-contamination.


Assuntos
Cloro/farmacologia , Contaminação de Alimentos/prevenção & controle , Lycopersicon esculentum/microbiologia , Viabilidade Microbiana , Microbiota , Salmonella enterica/efeitos dos fármacos , Contagem de Colônia Microbiana , Desinfetantes/farmacologia , Contaminação de Alimentos/análise , Manipulação de Alimentos/métodos , Tamanho da Partícula , Salmonella enterica/fisiologia
14.
Emerg Microbes Infect ; 9(1): 535-538, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32122270

RESUMO

Worldwide emergence of Salmonella enterica serovar Newport (S. Newport) infection in humans, in parallel with a significant increasing prevalence of antimicrobial resistance (AR), is a serious public health concern. However, the prevalence of S. Newport resistance in China remains largely unknown. A retrospective study of 287 S. Newport clinical isolates collected during 1997-2018 was undertaken for characterization of AR profiles using the micro-dilution assay. We found a recent emergence of colistin resistance in four Chinese clinical isolates, including mcr-1-positive isolates. Importantly, phylogenomic and microbiological investigations indicate multiple independent clonal transmission of colistin-resistant S. Newport isolates of different seafood origins. Our study highlights potential reservoirs for transmission of colistin resistance and suggests that the global food supply chain may facilitate this dissemination.


Assuntos
Colistina/farmacologia , Infecções por Salmonella/microbiologia , Salmonella enterica/isolamento & purificação , Farmacorresistência Bacteriana , Humanos , Salmonella enterica/efeitos dos fármacos
15.
Poult Sci ; 99(3): 1387-1394, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32111313

RESUMO

The antibacterial properties of egg yolk antibodies have been known for many years. Enhanced antibiotic resistance has resulted in increased need for using these antibodies as an alternative. In the present study, generation, capsulation, and inhibition growth properties of IgY directed against Salmonella enterica subsp. enterica serovar Infantis (SI) were evaluated. White Leghorn layer hens were immunized using whole cell of inactivated SI. Salmonella Infantis-specific antibody activities in sera and egg yolk were determined by ELISA. A total of 480 one-day-old male "Cobb 500" chicks were randomly divided into 8 groups, with 6 replications of 10 birds kept for 21 D. All birds from 7 challenged groups were orally inoculated with 1 mL of SI suspension (1 × 107 CFU/mL) at 3 and 4 D of age. Two groups were dietary supplemented with 5 g/kg immune powdered yolk or nonimmune powdered yolk. One group was dietary supplemented with 12.8 g/kg capsulated immune yolk (CIY). Two groups were given 8.3 mL/L of immune water-soluble yolk or nonimmune water-soluble yolk fraction in drinking water. In the antibiotic group, 1 mL/L Enrofloxacin 10% was added to drinking water. All supplements except for the antibiotic (on Day 4 for 10 D) were added on day one and continued during the experiment. Negative and positive control groups received no supplements. During the experiment, among the challenged groups, the minimum SI cecal colonization and the lowest isolation of SI from the liver (P < 0.01) was observed in the antibiotic group. Following antibiotic group, in the group receiving CIY, colonization of bacteria in ceca and liver was significantly reduced during the second and third weeks of the experiment (P < 0.01). According to the results, capsulated specific IgY has a beneficial effect in reducing the colonization of Salmonella under the conditions of this study in comparison with other forms of IgY antibody.


Assuntos
Anticorpos Antibacterianos/imunologia , Galinhas , Gema de Ovo/fisiologia , Imunoglobulinas/imunologia , Doenças das Aves Domésticas/prevenção & controle , Salmonelose Animal/prevenção & controle , Salmonella enterica/fisiologia , Ração Animal/análise , Animais , Dieta/veterinária , Suplementos Nutricionais/análise , Feminino , Intestinos/microbiologia , Masculino , Doenças das Aves Domésticas/microbiologia , Distribuição Aleatória , Salmonelose Animal/microbiologia , Salmonella enterica/efeitos dos fármacos , Sorogrupo
16.
Zhonghua Yu Fang Yi Xue Za Zhi ; 54(3): 323-326, 2020 Mar 06.
Artigo em Chinês | MEDLINE | ID: mdl-32187940

RESUMO

To conduct outbreak identification and transmission factor analysis of typhoid epidemic occurred in Xinqiao town, Jiangyin city from June to September 2016. A total of 14 strains of Salmonella typhi isolated from confirmed cases were collected, and 65 external environment samples and 13 food samples related to the outbreak were taken. Real-time PCR was used to detect specific gene of Salmonella typhi in the samples. Conventional method was used to isolate strains. The strains isolated from both the samples and patients in the epidemic were subjected to antimicrobial susceptibility testing and PFGE molecular characteristics. Salmonella typhi strain was isolated from one external sample (well water of a deli processing plant). The results of drug susceptibility showed that 15 strains were resistant to nalidixic acid. A total of 15 strains of Salmonella typhi were divided into 2 molecular patterns by pulsed field gel electrophoresis. The fingerprints of PFGE from the 13 patients and the environmental isolate were completely consistent, and there was one band difference from the other patient isolate. Combined with the epidemiological investigation and laboratory test results, it was determined that the outbreak was caused by genetic clone of the same Salmonella typhi. Food processing plant should be one of the key links.


Assuntos
DNA Bacteriano/genética , Surtos de Doenças , Epidemias , Salmonella enterica/genética , Salmonella typhi/genética , Febre Tifoide/epidemiologia , Antibacterianos/uso terapêutico , China/epidemiologia , Resistência Microbiana a Medicamentos , Eletroforese em Gel de Campo Pulsado , Humanos , Testes de Sensibilidade Microbiana , Reação em Cadeia da Polimerase em Tempo Real , Salmonella enterica/efeitos dos fármacos , Salmonella enterica/isolamento & purificação , Salmonella typhi/classificação , Salmonella typhi/efeitos dos fármacos , Salmonella typhi/isolamento & purificação , Febre Tifoide/diagnóstico , Febre Tifoide/tratamento farmacológico , Febre Tifoide/microbiologia
17.
Int J Food Microbiol ; 322: 108572, 2020 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-32169770

RESUMO

Global dissemination of non-typhoidal Salmonella producing extended-spectrum ß-lactamase (ESBL) is a public-health concern. Recently, the prevalence of Salmonella spp. resistant to third-generation cephalosporins has been increasing in food-producing animals in Korea. In this study, we investigated resistance mechanisms and molecular characteristics of S. Virchow isolates resistant to extended-spectrum cephalosporins (ESCs). We obtained 265 S. Virchow isolates from fecal and carcasses samples of cattle (n = 2), pigs (n = 7), and chickens (n = 256) during 2010-2017, and observed high ESC-resistance (63.8%, 169/265); most of the resistant isolates (96.4%) were obtained from chickens. ESC-resistant S. Virchow isolates (n = 169) showed significantly higher resistance rates to other antimicrobials (especially aminoglycosides and tetracycline, p-value <0.0001), as well as prevalence of multidrug resistance, than did ESC-susceptible S. Virchow isolates (n = 96). All ESC-resistant S. Virchow produced CTX-M-15-type ESBL (n = 147) and/or CMY-2-type AmpC ß-lactamase (n = 23). ESC-resistant S. Virchow represented seven pulsotypes, predominantly composed of type II (58.6%) and III (26.0%), detected in 69 farms in 10 provinces, and 33 farms in 7 provinces, respectively. Genes encoding ESC-resistance were horizontally transferred by conjugation to recipient E. coli J53; this was demonstrated in 28.8% (42/146) of blaCTX-M-15-positive isolates and in 50.0% (11/22) of blaCMY-2-positive isolates. All conjugative plasmids carrying blaCTX-M-15 and blaCMY-2 genes belonged to ST2-IncHI2 and ST12/CC12-IncI1, respectively. Genetic features of transferred bla genes were involved with ISEcp1 in both blaCTX-M-15 and blaCMY-2; ISEcp1 plays a critical role in the efficient capture, expression, and mobilization of bla genes. In addition to blaCTX-M-15 genes, resistance markers to aminoglycosides and/or tetracycline were co-transferred to recipient E. coli J53. Our results show a high prevalence of ESBL-producing S. Virchow in chickens and chicken carcasses. Specific blaCTX-M-15 and blaCMY-2-carrying S. Virchow clones and plasmids were predominant in food-producing animals nationwide. Restriction of antimicrobial use and proper biosecurity practices at the farm level should be urgently implemented in the poultry industry.


Assuntos
Microbiologia de Alimentos , Salmonella enterica/enzimologia , Salmonella enterica/isolamento & purificação , beta-Lactamases/genética , Animais , Antibacterianos/farmacologia , Proteínas de Bactérias , Bovinos/microbiologia , Cefalosporinas/farmacologia , Galinhas/microbiologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Farmacorresistência Bacteriana/genética , Plasmídeos/genética , Aves Domésticas/microbiologia , República da Coreia , Salmonella enterica/efeitos dos fármacos , Salmonella enterica/genética , Sorogrupo , Suínos/microbiologia , beta-Lactamases/metabolismo
18.
J Food Prot ; 83(3): 412-417, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-32050031

RESUMO

ABSTRACT: Fresh produce, such as blueberries, continues to be a source of foodborne illness in the United States. Despite new practices and intervention technologies, blueberries and other produce are contaminated with foodborne pathogens, such as Salmonella. The aim of this study was to evaluate the efficacy of chlorine dioxide gas (CDG) against Salmonella enterica serovars Newport, Stanley, Muenchen, and Anatum on artificially contaminated whole fresh blueberries. Blueberries were dip inoculated into a 400-mL bath containing a Salmonella serovar cocktail of either ca. 6 or 9 log CFU/mL. Samples were dried for either 2 or 24 h before treatment with 1.5 or 3 mg of CDG/L of air to a final treatment of 3.55 to 6 ppm/h/g of blueberry. Salmonella cells were recovered by stomaching CDG-treated and nontreated control samples with 0.1% peptone and enumerated on xylose lysine Tergitol 4 agar. CDG treatments achieved up to a 5.63-log CFU/g reduction of the cocktail using 5.5 ppm/h/g, whereas the lowest treatment, 4 ppm/h/g (1.5 mg of CDG/L), was still capable of a 4.45-log CFU/g reduction. Incubation time significantly (P < 0.001) affected CDG efficacy against both inoculation concentrations. Additionally, all serovars responded similarly to CDG treatment when tested individually (P > 0.0691). Finally, the availability of a water reservoir during treatments did not have a significant effect (P = 0.9818) on CDG efficacy in this study. Our results demonstrate that CDG can be an efficacious treatment option for whole blueberry decontamination.


Assuntos
Mirtilos Azuis (Planta)/microbiologia , Compostos Clorados/farmacologia , Desinfetantes , Óxidos/farmacologia , Salmonella enterica/efeitos dos fármacos , Cloro , Contagem de Colônia Microbiana , Desinfetantes/farmacologia , Microbiologia de Alimentos , Sorogrupo
19.
Microb Genom ; 6(2)2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32003708

RESUMO

To establish the prevalence of mobile colistin resistance (mcr) genes amongst Salmonella enterica isolates obtained through public health surveillance in England (April 2014 to September 2017), 33 205 S. enterica genome sequences obtained from human, food, animal and environmental isolates were screened for the presence of mcr variants 1 to 8. The mcr-positive genomes were assembled, annotated and characterized according to plasmid type. Nanopore sequencing was performed on six selected isolates with putative novel plasmids, and phylogenetic analysis was used to provide an evolutionary context for the most commonly isolated clones. Fifty-two mcr-positive isolates were identified, of which 32 were positive for mcr-1, 19 for mcr-3 and 1 for mcr-5. The combination of Illumina and Nanopore sequencing identified three novel mcr-3 plasmids and one novel mcr-5 plasmid, as well as the presence of chromosomally integrated mcr-1 and mcr-3. Monophasic S. enterica serovar Typhimurium accounted for 27/52 (52 %) of the mcr-positive isolates, with the majority clustering in clades associated with travel to Southeast Asia. Isolates in these clades were associated with a specific plasmid range and an additional extended-spectrum beta-lactamase genotype. Routine whole-genome sequencing for public health surveillance provides an effective screen for novel and emerging antimicrobial determinants, including mcr. Complementary long-read technologies elucidated the genomic context of resistance determinants, offering insights into plasmid dissemination and linkage to other resistance genes.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Colistina/farmacologia , Genoma Bacteriano , Salmonella enterica/genética , Animais , Antibacterianos/metabolismo , Proteínas de Bactérias/metabolismo , Farmacorresistência Bacteriana , Inglaterra/epidemiologia , Microbiologia Ambiental , Microbiologia de Alimentos , Humanos , Testes de Sensibilidade Microbiana , Filogenia , Plasmídeos/genética , Plasmídeos/metabolismo , Vigilância em Saúde Pública , Infecções por Salmonella/epidemiologia , Infecções por Salmonella/microbiologia , Salmonelose Animal/epidemiologia , Salmonelose Animal/microbiologia , Salmonella enterica/classificação , Salmonella enterica/efeitos dos fármacos , Salmonella enterica/isolamento & purificação
20.
PLoS One ; 15(1): e0220427, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32004341

RESUMO

Identifying and controlling the emergence of antimicrobial resistance (AMR) is a high priority for researchers and public health officials. One critical component of this control effort is timely detection of emerging or increasing resistance using surveillance programs. Currently, detection of temporal changes in AMR relies mainly on analysis of the proportion of resistant isolates based on the dichotomization of minimum inhibitory concentration (MIC) values. In our work, we developed a hierarchical Bayesian latent class mixture model that incorporates a linear trend for the mean log2MIC of the non-resistant population. By introducing latent variables, our model addressed the challenges associated with the AMR MIC values, compensating for the censored nature of the MIC observations as well as the mixed components indicated by the censored MIC distributions. Inclusion of linear regression with time as a covariate in the hierarchical structure allowed modelling of the linear creep of the mean log2MIC in the non-resistant population. The hierarchical Bayesian model was accurate and robust as assessed in simulation studies. The proposed approach was illustrated using Salmonella enterica I,4,[5],12:i:- treated with chloramphenicol and ceftiofur in human and veterinary samples, revealing some significant linearly increasing patterns from the applications. Implementation of our approach to the analysis of an AMR MIC dataset would provide surveillance programs with a more complete picture of the changes in AMR over years by exploring the patterns of the mean resistance level in the non-resistant population. Our model could therefore serve as a timely indicator of a need for antibiotic intervention before an outbreak of resistance, highlighting the relevance of this work for public health. Currently, however, due to extreme right censoring on the MIC data, this approach has limited utility for tracking changes in the resistant population.


Assuntos
Antibacterianos/farmacologia , Cefalosporinas/farmacologia , Cloranfenicol/farmacologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Salmonella enterica/efeitos dos fármacos , Animais , Teorema de Bayes , Conjuntos de Dados como Assunto , Humanos , Modelos Lineares , Testes de Sensibilidade Microbiana , Saúde Pública , Infecções por Salmonella/microbiologia , Salmonella enterica/crescimento & desenvolvimento , Salmonella enterica/isolamento & purificação , Suínos , Doenças dos Suínos/microbiologia
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