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1.
Front Cell Infect Microbiol ; 12: 869339, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35646717

RESUMO

Listeria monocytogenes is an opportunistic intracellular pathogen causing an infection termed listeriosis. Despite the low incidence of listeriosis, the high mortality rate in individuals at risk makes this bacterium one of the most dangerous foodborne pathogens. Reports about a relapse of infection after antibiotic treatment suggest that the bacteria may be able to evade antibiotic treatment and persist as a dormant, antibiotic-tolerant subpopulation. In this study, we observed intracellular generation of antibiotic-resistant L-forms of Listeria monocytogenes following Ampicillin treatment of Listeria monocytogenes infected cells. Detection and identification of intracellular Listeria L-forms was performed by a combination of fluorescence in-situ hybridization and confocal laser scanning microscopy. Using micromanipulation, it was possible to isolate single intracellular L-form cells that following transfer into fresh medium gave rise to pure cultures. In conclusion, the results obtained here provide strong evidence that antibiotic treatment of infected host cells can induce the formation of L-forms from intracellular Listeria monocytogenes. Furthermore, our results suggest that intracellular L-forms persist inside host cells and that they represent viable bacteria, which are still able to grow and proliferate.


Assuntos
Listeria monocytogenes , Listeriose , Ampicilina/farmacologia , Antibacterianos/farmacologia , Humanos , Listeriose/tratamento farmacológico , Listeriose/microbiologia
2.
J Prev Med Hyg ; 63(1): E139-E141, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35647368

RESUMO

Endophthalmitis due to Listeria monocytogenes is a rare form of listeriosis. Here, we report two cases that occurred in patients with different medical history, a 46-years-old woman with no comorbidities and an elderly man with several comorbidities. There was no history of trauma or surgery in either patient suggesting an endogenous origin. Despite antibiotic treatment, both patients showed poor visual acuity outcomes. Subtyping clinical isolates using whole genome sequencing could allow to characterise Listeria monocytogenes strains involved in rare clinical manifestation, such as in unusual anatomical sites, even in immunocompetent patients.


Assuntos
Endoftalmite , Listeria monocytogenes , Listeriose , Idoso , Endoftalmite/tratamento farmacológico , Feminino , Humanos , Listeria monocytogenes/genética , Listeriose/tratamento farmacológico , Pessoa de Meia-Idade
3.
Food Microbiol ; 106: 104054, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35690447

RESUMO

Human pathogens can develop biofilm structures on different artificial substrates common in the food industry. In this study, we investigated the inactivation efficacy of low-energy X-ray irradiation on Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes biofilms on food contact surfaces, including polyvinyl chloride (PVC), stainless steel with finish 2B (STS 2B), and Teflon. The numbers of viable cells in biofilms on all test coupons were significantly (p < 0.05) reduced as the X-ray dose increased. Interestingly, different biofilm inactivation levels were observed relative to various material surfaces. Teflon showed the lowest D5d (dose required for a 5-log reduction in cell count) values among three groups of coupons, whereas PVC exhibited higher D5d values than the other two coupons. The mechanism of the X-ray antibiofilm effect was identified through the measurement of extracellular polymeric substances (EPS) in biofilms. X-ray irradiation could remove exopolysaccharides, which are major component of EPS and the removal rate increased with increasing irradiation dose. The analyses also confirmed that the disintegration of EPS was strongly related to the trends of biofilm inactivation on different coupon surfaces. This study is the first to demonstrate that X-ray irradiation effectively inactivates major foodborne pathogen biofilms on various food contact surfaces and to evaluate its antibiofilm mechanisms to enhance safety in the food processing industries.


Assuntos
Microbiologia de Alimentos , Listeria monocytogenes , Biofilmes , Contagem de Colônia Microbiana , Humanos , Politetrafluoretileno/farmacologia , Cloreto de Polivinila/farmacologia , Aço Inoxidável , Raios X
4.
Food Microbiol ; 106: 104033, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35690452

RESUMO

Chlorine and peroxyacetic acid (PAA) are commonly applied in dump tanks and flume systems in commercial fresh apple packing lines; however, little is known about their practical efficacies in dump tank water systems. This study evaluated the efficacies of chlorine and PAA to control Listeria monocytogenes on fresh apples and cross-contamination in simulated dump tank water (SDTW). Efficacies of chlorinated water with initial free chlorine (FC) of 25-100 ppm against L. monocytogenes on apples were significantly impacted by the presence of organic matter, especially for chlorine with 25 ppm initial FC. Chlorine with initial FCs of 50-100 ppm and 2 min contact reduced L. monocytogenes on apples by ∼0.9 log10 CFU/apple in SDTW with 1000 ppm chemical oxygen demand (COD). However, 2-5 min wash of chlorine with 25 ppm initial FC only led to ∼0.3 log10 CFU/apple reduction of L. monocytogenes on apples in SDTW compared to ∼0.9 log10 CFU/apple reduction in clean water. The impacts of organic matter on the antimicrobial efficacy of PAA are concentration dependent. At 20-80 ppm and tested contact times (2-5 min), efficacies of PAA against L. monocytogenes were not influenced by organic matter presented in SDTW; 2-5 min wash with PAA 80 ppm caused 1.7-1.8 log10 CFU/apple log reduction. However, the anti-Listeria efficacy of 10 ppm PAA was significantly lower in SDTW than in clean water. Sanitizers at the tested concentrations reduced L. monocytogenes transferred from contaminated apples to uncontaminated apples and SDTW but did not eliminate it. There were 1.7-0.6 and 1.0-0.9 log10 CFU/apple of L. monocytogenes transferred to uninoculated apples in SDTW treated with 50-100 ppm FC and 60-80 ppm PAA, respectively, for 2 min, while 3.6-3.7 log10 CFU/apple of L. monocytogenes were transferred to uncontaminated apples in SDTW without any sanitizer treatments. Data indicated that sanitizer treatments in SDTW are effective but can be further improved to ensure the microbial safety of apples.


Assuntos
Desinfetantes , Listeria monocytogenes , Malus , Cloro/farmacologia , Contagem de Colônia Microbiana , Desinfetantes/farmacologia , Manipulação de Alimentos , Microbiologia de Alimentos , Ácido Peracético/farmacologia , Água/farmacologia
5.
Food Res Int ; 157: 111367, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35761627

RESUMO

Listeria monocytogenes is a foodborne pathogen that can form biofilms in food processing facilities even under unfavorable growth environment. This study aimed to evaluate the biofilm eradication ability of Listeria-specific bacteriophage (phage) cocktail (LMPC01+02+03) against L. monocytogenes young (1 day) and mature (3 days) biofilms formed on food contact materials (FCMs: polyethylene, polypropylene, and stainless steel) at 4, 15, and 30 °C. In addition, virulence-related genes and biofilm structure parameters of the phage-treated biofilms were investigated. The biofilm eradication ability of the phage cocktail was evaluated on 96 well and MBEC plate, and the results revealed that a multiplicity-of-infection (MOI) 100 of the phage cocktail exhibited the ability of eradicate biofilms. Using MOI 100, the phage cocktail treatment on the biofilms formed on FCMs for 8 h reduced over 2 log CFU/cm2 of the young biofilms, and approximately 1 log CFU/cm2 of the mature biofilms. In addition, the phage treatment against the biofilms resulted in a significant up-regulation of two genes (flaA and motB), and up/down-regulation or no changes in three genes (hlyA, prfA, and actA). Confocal and scanning electron microscopy images revealed the loss of the biofilm matrix after the phage treatment, and quantitative analysis revealed a reduction in the structural parameters of the biofilm, except the microcolonies at the substratum level, which increased. These results suggested that MOI 100 of the phage cocktail (LMPC01+02+03) was an effective tool for eradicating L. monocytogenes biofilms formed on FCMs, and it is essential to develop a countermeasure to eradicate the biofilm remaining after phage treatment.


Assuntos
Bacteriófagos , Listeria monocytogenes , Bacteriófagos/genética , Biofilmes , Contagem de Colônia Microbiana , Virulência
6.
Klin Lab Diagn ; 67(6): 362-368, 2022 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-35749602

RESUMO

Results from research on isolation, identification, and study of biological properties of L. monocytogenes clinical isolates and Listeria spp test strains are presented. Peculiarities of modern research methods for indicating and identifying pathogenic listeria to improve the quality of laboratory studies of clinical material are studied. The culture method provides reliable results of microbiological analyses upon detecting Listeria spp. The presented list and algorithm of the laboratory diagnostic methods can be used as a basis for elaborating regulatory documents for carrying out microbiological research on any biological material for the presence of bacteria of the genus Listeria spp. and L. monocytogenes species in it.


Assuntos
Listeria monocytogenes , Listeria , Humanos , Listeria/genética
7.
J Med Microbiol ; 71(6)2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35723974

RESUMO

Microorganisms produce a wide variety of volatile organic compounds (VOCs) as products of their metabolism and some of them can be specific VOCs linked to the microorganism's identity, which have proved to be helpful for the diagnosis of infection via odour fingerprinting. The aim of this study was to determine the VOCs produced and consumed to characterize the volatile metabolism of seven isolates of different clonal complexes (CCs) of Listeria monocytogenes. For this purpose, dichloromethane extracts from the thioglycolate broth medium were analysed by gas chromatography coupled to mass spectrometry (GC/MS). Also, multivariate analyses were applied to the data obtained. Results showed that all the isolates of L. monocytogenes produced de novo isobutanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-(methylthio)-1-propanol, acetic acid, isobutyric acid, butanoic acid, and isovaleric acid. Significant differences were found among isolates for the production amount of these volatiles, which allowed their differentiation. Thus, CC4 (ST-219/CT-3650) and CC87 (ST-87/CT-4557) showed an active volatile compounds metabolism with high consumption nitrogen and sulphur compounds and production of alcohols and acids, and CC8 (ST-8/CT-8813) and CC3 (ST-3/CT-8722) presented a less active volatile metabolism. Moreover, within the VOCs determined, huge differences were found in the production of butanol among the seven isolates analysed, being probably a good biomarker to discriminate among isolates belonging to different CCs. Hence, the analysis of volatile profile generated by the growth of L. monocytogenes in vitro could be a useful tool to differentiate among CCs isolates.


Assuntos
Listeria monocytogenes , Compostos Orgânicos Voláteis , Meios de Cultura , Cromatografia Gasosa-Espectrometria de Massas/métodos , Compostos Orgânicos Voláteis/metabolismo
8.
Int J Food Microbiol ; 376: 109773, 2022 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-35689970

RESUMO

In nature, bacterial pathogens like L. monocytogenes, live in nature associated with other microbial species in spatially-structured communities called biofilms. In the food industry, biofilms contribute to the survival and persistence of L. monocytogenes within processing facilities, thereby enhancing its risk of cross-contaminating food products. The challenge of combating biofilms has triggered the search for new antibiofilm strategies including devising ways to interfere with cell communication mechanisms (quorum-sensing) that are known to be involved with biofilm development regulation. The aim of this study was to explore cell communication signals in a L. monocytogenes-carrying microbial community isolated from a meat processing plant (location No. 96) in order to elucidate the ecological interactions that could serve as a starting point for the development of new antibiofilm strategies. Quorum quenching (QQ) and quorum sensing (QS) activities were screened among 31 bacterial strains isolated from location No. 96. Whereas no QQ activity was detected against short-chain lactone N-hexanoyl-DL-homoserine lactone (C6-HSL), it was detected against N-dodecanoyl-DL-homoserine lactone (C12-HSL) in 7 isolates (23%), particularly in Pseudomonas monteilli, Rhodococcus sp. and Rhodococcus erythropolis. QS activity assays detected HC4, C4, C6, OC6, HC10 and C16 in all the extracts, being C4, C6 and OC6 with predominantly produced by Pseudomonas monteilli, Pseudomonas gesardii, Psychrobacter maritimus and Paracoccus sp. High production levels of C16-HSL by Paracoccus sp. and the role of this long-chain lactone as a self-inhibitor of cell aggregation led us to carry out further studies focused on the effects of a Paracoccus lactone extract (PLE) against the biofilm formation by L. monocytogenes. A quantitative microscopic analysis demonstrated a significant decrease (p < 0.05) in the area occupied by biofilms formed on stainless steel (SS) coupons by different strains of L. monocytogenes in the presence of PLEs. Conversely, no significant differences were observed in the total number of viable adhered cells on SS coupons with or without PLE. The observed effect was partially reproduced by the addition of pure C16-HSL to 24 h-biofilms of L. monocytogenes L1.96. These results demonstrate that the observed effects can be attributed, at least partially, to the HSLs contained in the PLE. Overall, the present results highlight how interspecies communication within a biofilm can open up new insights for the development of new ways to combat biofilm.


Assuntos
Listeria monocytogenes , Microbiota , Biofilmes , Lactonas , Percepção de Quorum
9.
Sci Immunol ; 7(72): eabp8632, 2022 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-35714199

RESUMO

In this issue of Science Immunology, Barreto de Albuquerque et al. track immune responsiveness to the foodborne pathogen Listeria monocytogenes during oral infection. Their findings extend the notion of compartmentalized immunity within the gastrointestinal tract to the oral cavity and provide previously unkown insights into regional specialization of oral immunity.


Assuntos
Listeria monocytogenes , Listeriose , Trato Gastrointestinal , Humanos , Imunidade nas Mucosas , Mucosa Bucal
10.
BMC Microbiol ; 22(1): 160, 2022 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-35717165

RESUMO

BACKGROUND: The food industry is increasingly becoming more scrutinized, given the frequency and intensity with which zoonotic diseases are being reported. Pathogen tracking has become more applicable with regards food safety. It is in this regard that the present study was formulated to track Listeria species. in freshly slaughtered cattle carcasses by utilizing standard and molecular biological techniques. METHODS: A cross-sectional study design was conducted from March to December 2020 with 200 samples being equally collected in the rainy and dry seasons. A total of 180 and 20 swabs were aseptically collected from carcasses and the environment respectively. Samples were first subjected to pre-enrichment in half-strength Fraser broth followed by enrichment in full strength Fraser broth and subsequent plating on Listeria agar. Listeria growth characteristics were identified up to species level based on their morphological and biochemical characteristics. Further, molecular detection and phylogenetic analysis was conducted. Quantitative proportionate survey data were analyzed using Stata Version 15 software to estimate crude prevalence taking into account complex design at abattoir level. Factors associated with contamination were characterized using logistic regression. Sequences were analyzed using, Genetyyx version 12 and phylogenetic Mega. RESULTS: Of the 200 samples, 19 were positive for Listeria species identified as L.innocua 14/19 (73.7%) and L. monocytogenes 5/19 (26.3%). All isolates were from freshly slaughtered carcasses, and none from environment. Siginificant differences in contamination levels were observed based on season: rainy season yielded 14 (73.6%) whilst the dry season 5 (26.3%). The L. monocytogenes strains showed a high degree of homogeneity on phylogenetic analysis and clustered based on abattoir. Seasonality was identified as a major determinant influencing contamination based on the final logistic regression model. CONCLUSION: This study found evidence of L. monocytogenes contamination on traditionally raised beef carcasses across various abattoirs surveyed. The failure to find Listeria contamination on the abattoir environment may to a greater extent intimate cattle carccases as primary sources of contamination. However, a more comprerehnsive study incorporating different geographical regions is needed to conclusively ascertain these present findings.


Assuntos
Listeria monocytogenes , Listeria , Animais , Bovinos , Estudos Transversais , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Listeria/genética , Filogenia , Zâmbia
11.
Food Microbiol ; 106: 103757, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35690455

RESUMO

In response to the massive use of biocides for controlling Listeria monocytogenes (hereafter Lm) contaminations along the food chain, strains showing biocide tolerance emerged. Here, accessory genomic elements were associated with biocide tolerance through pangenome-wide associations performed on 197 Lm strains from different lineages, ecological, geographical and temporal origins. Mobile elements, including prophage-related loci, the Tn6188_qacH transposon and pLMST6_emrC plasmid, were widespread across lineage I and II food strains and associated with tolerance to benzalkonium-chloride (BC), a quaternary ammonium compound (QAC) widely used in food processing. The pLMST6_emrC was also associated with tolerance to another QAC, the didecyldimethylammonium-chloride, displaying a pleiotropic effect. While no associations were detected for chemically reactive biocides (alcohols and chlorines), genes encoding for cell-surface proteins were associated with BC or polymeric biguanide tolerance. The latter was restricted to lineage I strains from animal and the environment. In conclusion, different genetic markers, with polygenic nature or not, appear to have driven the Lm adaptation to biocide, especially in food strains but also from animal and the environment. These markers could aid to monitor and predict the spread of biocide tolerant Lm genotypes across different ecological niches, finally reducing the risk of such strains in food industrial settings.


Assuntos
Desinfetantes , Listeria monocytogenes , Animais , Compostos de Benzalcônio/farmacologia , Cloretos , Desinfetantes/farmacologia , Farmacorresistência Bacteriana/genética , Ecossistema , Genômica
12.
Int J Mol Sci ; 23(11)2022 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-35682909

RESUMO

L. monocytogenes, consisting of 13 serotypes, is an opportunistic food-borne pathogen that causes different host reactions depending on its serotypes. In this study, highly toxic L. monocytogenes&nbsp;10403s resulted in more severe infections and lower survival rates. Additionally, to investigate the remodeling of the host proteome by strains exhibiting differential toxicity, the cellular protein responses of intestinal organoids were analyzed using tandem mass tag (TMT) labeling and high-performance liquid chromatography-mass spectrometry. The virulent strain 10403s caused 102 up-regulated and 52 down-regulated proteins, while the low virulent strain M7 caused 188 up-regulated and 25 down-regulated proteins. Based on the analysis of gene ontology (GO) and KEGG databases, the expressions of differential proteins in organoids infected by L. monocytogenes&nbsp;10403s (virulent strain) or M7 (low virulent strain) were involved in regulating essential processes such as the biological metabolism, the energy metabolism, and immune system processes. The results showed that the immune system process, as the primary host defense response to L. monocytogenes, comprised five pathways, including ECM-receptor interaction, the complement and coagulation cascades, HIF-1, ferroptosis, and NOD-like receptor signaling pathways. As for the L. monocytogenes&nbsp;10403s vs. M7 group, the expression of differential proteins was involved in two pathways: systemic lupus erythematosus and transcriptional mis-regulation in cancer. All in all, these results revealed that L. monocytogenes strains with different toxicity induced similar biological functions and immune responses while having different regulations on differential proteins in the pathway.


Assuntos
Listeria monocytogenes , Listeriose , Proteínas de Bactérias/metabolismo , Humanos , Organoides/metabolismo , Proteômica , Virulência
13.
Food Res Int ; 156: 111118, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35651000

RESUMO

Due to the ubiquitous character of Listeria monocytogenes multiple strains of the pathogen may end up co-existing in/on the same final products and could potentially cause infection during consumption. Such multiple strain contamination may occur in different stages of the food supply chain. The present study evaluated the effect of oxygen availability and matrix structure on inter-strain interactions of L. monocytogenes that may occur at high population levels in/on different dairy model systems. L. monocytogenes strains C5 and ScottA (4b), 6179 (1/2a) and PL25 (1/2b) were selected as resistant to different antibiotics (enabling selective enumeration of each strain in co-culture) and inoculated (2.0-3.0 log CFU/mL, g or cm2) in Ricotta and Camembert broth (1 dairy product: 2 » Ringer solution) and in/on dairy-based structured media (dairy broth supplemented with 0.6 and 1.4% agar), in single and two-strain cultures (1:1 strain ratio). Bacterial growth was assessed during storage at 7 °C, under aerobic, hypoxic and anoxic conditions. Every experimental treatment was tested with three biological replicates and two technical repeats (n = 3 × 2). The simultaneously presence of different strains of the pathogen in/on the same substrate did not affect neither the duration of the lag phase nor the growth rate of the co-cultured strains. The observed inter-strain interactions were related with the final population reached/decrease during storage and occurred after the "critical" population density of ca. 6.0 log CFU/mL, g or cm2. The phenomenon was more pronounced in/on Ricotta than in/on Camembert-based substrates, indicating that the composition and the available nutrients of the substrate may affect the interactions that expressed as difference in the final population level between singly and co-cultured strains. Under aerobic and hypoxic conditions, most of the observed interactions were more pronounced in dairy-based broths and were mitigated with the addition of agar. The elimination of oxygen resulted in a prolonged lag time, which lasted at least 5 days and no observed interactions by the end of storage, due to low microbial counts. Investigating inter-strain interactions during growth in/on different substrates, which may have undergone temperature abuse during their transport along the supply chain or during storage in household refrigerators, could assist in explaining the mismatch between clinical and food samples during outbreak investigations.


Assuntos
Listeria monocytogenes , Ágar , Contagem de Colônia Microbiana , Microbiologia de Alimentos , Humanos , Oxigênio , Densidade Demográfica
14.
Food Res Int ; 156: 111143, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35651015

RESUMO

Listeria monocytogenes is a gram-positive pathogen, that usually adheres to stainless steel (SS), and other abiotic surfaces in food processing that undergo repeated cleaning and cause the spread of Listeria. Through the enumeration of biofilm cells, extracellular polymeric substance (EPS) component and the scanning electron microscopy (SEM) analysis of biofilms, it was found that the ratio of cells and extracellular matrix is affected by nutrition status. Regardless of the temperature, all strains exhibited a higher adhesion ability when exposed to 10-fold diluted TSB-YE (DTSB-YE, nutrition deficiency). Three hour initial adhesion was significantly positively correlated with biofilm formation (p<0.01). DTSB-YE enhances initial attachment and subsequently promotes biofilm formation. The SEM analysis also showed that in DTSB-YE the adhesion and covered area of the attached cells were higher than those in TSB-YE (rich media). The amount of both extracellular polysaccharides and proteins was significantly higher when incubated in DTSB-YE than TSB-YE. The highest biofilm formation of Lm83 was observed in DTSBYE independent of temperature. The effects of nutrition deficiency on the expression of critical biofilm-associated genes of Lm 83 planktonic and biofilm cells were measured. The gene expression levels of inlA and sigB in biofilm cells in TSB-YE and DTSB-YE were approximately 95.7% and 88.0% and 42.2% and 45.7% lower than those in planktonic cells, respectively. However, the expression of inlA in DTSB-YE was significantly higher (p<0.05) than that in TSB-YE for the same cell state. Interestingly, the gene expression of motB was considerably higher in DTSB-YE than in TSBYE, regardless of the state. These results indicate that better cell motility in nutrient deficiencies might facilitate the cell aggression to promote biofilm formation.


Assuntos
Listeria monocytogenes , Biofilmes , Matriz Extracelular de Substâncias Poliméricas , Microbiologia de Alimentos , Expressão Gênica , Cinética , Listeria monocytogenes/genética
15.
Adv Food Nutr Res ; 100: 211-264, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35659353

RESUMO

The concern with food safety in the milk chain begins with the quality of the raw milk. Due to the health hazard that this food can carry when contaminated, the focus of studies has turned to microbiological and chemical contaminants that may be present in raw milk. There is an essential concern about conventional pathogens (Shiga toxin-producing Escherichia coli, Salmonella spp., Listeria monocytogenes, Campylobacter spp., Salmonella spp., and coagulase-positive Staphylococcus spp.) and emerging pathogens (Arcobacter butzleri, Yersinia enterocolitica, Mycobacterium avium ssp. paratuberculosis, Helicobacter pylori, and Cronobacter sakazakii) found in raw milk and dairy products. In addition, a growing public health issue has been raised regarding antimicrobial-resistant pathogens and commensal strains found in milk and dairy products. The antibiotic residues in milk can also damage health, such as allergies, and cause technological problems in dairy products processing. This health issue extends to other chemical contaminants such as heavy metals, pesticides, polycyclic aromatic hydrocarbons, melamine, dioxins, polychlorinated biphenyls, plasticizers, and additives in milk and dairy products. Other chemical substances formed by microorganisms are also of high importance, such as biogenic amines and mycotoxins. Therefore, this chapter aimed to revise and discuss relevant biological and chemical risks to ensure the safety and quality of raw milk and dairy products.


Assuntos
Listeria monocytogenes , Leite , Animais , Microbiologia de Alimentos , Leite/microbiologia , Salmonella
16.
Curr Microbiol ; 79(8): 232, 2022 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-35767082

RESUMO

The objective of this work is the study of the antifungal and antibacterial activity of Lactiplantibacillus plantarum S61 strains, isolated from traditional fermenting green olives against Rhodotorula glutinis UMP 22 and Listeria monocytogenes ATCC 19117, and its application in meat as bio-preservative agent. The cell-free supernatant (CFS) of Lpb. plantarum S61 shows high inhibition zones, which are 22.45 ± 0.49 and 17.75 ± 0.35 mm, against Rhodotorula glutinis and Listeria monocytogenes. The minimum fungicidal and bactericidal concentrations of the CFS obtained are 8% (v/v) and 10% (v/v), respectively. The competition assay, realized in liquid medium by co-culture of Lpb. plantarum S61 with Rho Rhodotorula glutinis and L. monocytogenes, led to inhibition percentages of 77.72% and 89.52%, respectively. However, the antimicrobial activity of Lpb. plantarum S61 was revealed a proteinaceous nature. Lpb. plantarum S61 strain allowed the reduction of L. monocytogenes in minced poultry meat during 7 days of storage at 4 °C. In addition, Lpb. plantarum S61 improved the physicochemical and color parameters of poultry minced meat. Lpb. plantarum S61 and/or its antimicrobial compounds can be applied as bio-preservative agent in meat product and food industry.


Assuntos
Síndrome de Fadiga Crônica , Listeria monocytogenes , Probióticos , Animais , Antibacterianos/farmacologia , Carne/microbiologia , Aves Domésticas , Rhodotorula
17.
Nature ; 606(7915): 769-775, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35676476

RESUMO

Adaptive immune components are thought to exert non-overlapping roles in antimicrobial host defence, with antibodies targeting pathogens in the extracellular environment and T cells eliminating infection inside cells1,2. Reliance on antibodies for vertically transferred immunity from mothers to babies may explain neonatal susceptibility to intracellular infections3,4. Here we show that pregnancy-induced post-translational antibody modification enables protection against the prototypical intracellular pathogen Listeria monocytogenes. Infection susceptibility was reversed in neonatal mice born to preconceptually primed mothers possessing L. monocytogenes-specific IgG or after passive transfer of antibodies from primed pregnant, but not virgin, mice. Although maternal B cells were essential for producing IgGs that mediate vertically transferred protection, they were dispensable for antibody acquisition of protective function, which instead required sialic acid acetyl esterase5 to deacetylate terminal sialic acid residues on IgG variable-region N-linked glycans. Deacetylated L. monocytogenes-specific IgG protected neonates through the sialic acid receptor CD226,7, which suppressed IL-10 production by B cells leading to antibody-mediated protection. Consideration of the maternal-fetal dyad as a joined immunological unit reveals protective roles for antibodies against intracellular infection and fine-tuned adaptations to enhance host defence during pregnancy and early life.


Assuntos
Imunidade Materno-Adquirida , Imunoglobulina G , Espaço Intracelular , Listeria monocytogenes , Mães , Gravidez , Acetilesterase , Animais , Animais Recém-Nascidos , Linfócitos B , Feminino , Imunidade Materno-Adquirida/imunologia , Imunoglobulina G/imunologia , Interleucina-10/biossíntese , Espaço Intracelular/imunologia , Espaço Intracelular/microbiologia , Listeria monocytogenes/imunologia , Listeriose/imunologia , Listeriose/prevenção & controle , Camundongos , Ácido N-Acetilneuramínico/metabolismo , Gravidez/imunologia , Lectina 2 Semelhante a Ig de Ligação ao Ácido Siálico , Linfócitos T
18.
Anal Methods ; 14(24): 2423-2430, 2022 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-35674012

RESUMO

Listeria monocytogenes (L. monocytogenes) is one of the most lethal pathogenic bacteria. Although the traditional microbial culture method has high sensitivity and selectivity for the diagnosis of L. monocytogenes, it is time-consuming and not suitable for on-site detection. A rapid, convenient and visualized on-site detection method is particularly needed. In this work, Fe3O4@UiO-66-NH2 was prepared for both magnetic separation and lateral flow immunoassay (LFIA) for the detection of L. monocytogenes by taking advantage of the easy separation of the magnetic core Fe3O4 and the high surface area of the outer layer UiO-66-NH2. Fe3O4@UiO-66-NH2 with a high surface area and good water-dispersibility and optical properties was synthesized by a simple hydrothermal process. It could directly adsorb on the surface of target bacteria and form Fe3O4@UiO-66-NH2-bacteria conjugates, without the labeling of an antibody. After magnetic separation and concentration, the Fe3O4@UiO-66-NH2-bacteria conjugates were detected by the antibody on the test line of the LFIA strip, resulting in a visible orange band. The capture efficiency and LFIA detection of Fe3O4@UiO-66-NH2 were optimized in this study. Under the optimal conditions, a good linear correlation between the test line intensity and the concentration of L. monocytogenes was obtained in the range of 105-108 CFU mL-1, and the limit of detection was 2.2 × 106 CFU mL-1 by the naked eye. The Fe3O4@UiO-66-NH2-based LFIA strip showed strong specificity for L. monocytogenes, and the detection took 45 min without culture enrichment. Therefore, the proposed Fe3O4@UiO-66-NH2-based strip showed the advantages of simple synthesis, being label-free, low cost, good selectivity and convenience.


Assuntos
Listeria monocytogenes , Nanocompostos , Imunoensaio/métodos , Fenômenos Magnéticos , Estruturas Metalorgânicas , Ácidos Ftálicos
19.
J Comp Pathol ; 194: 7-13, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35577461

RESUMO

A 27-year-old female white-faced saki (Pithecia pithecia) died following an onset of vomiting and ptyalism. Necropsy revealed lesions of suppurative ventriculitis, choroid plexitis, periventricular encephalitis and meningitis with intralesional gram-positive coccobacilli and paired rods. The saki also had suppurative to mononuclear hepatitis, mild intestinal crypt necrosis, proliferative glomerulonephritis, aortic arteriosclerosis, pulmonary interstitial fibrosis, chronic mild epicarditis, ovarian medullary arteriopathy and a focal superficial cerebral fibrotic nodule with surrounding chronic mixed cell inflammation. Listeria monocytogenes was cultured from liver and spinal cord. Intralesional Listeria bacteria were immunolabelled in brain sections and real-time polymerase chain reaction of brain tissue detected L. monocytogenes. Whole genome multilocus sequence typing characterized the cultured bacterial isolates as sequence type 6 and clonal complex 6. A database search for related clinical and food listerial outbreaks identified genetically related isolates but, because these isolates were more than 20 alleles distant from the saki isolates, they were not a related cluster. Reports of listeriosis in non-human primates are infrequent, and when infections do occur, they tend to be haematogenous with the propensity to cause meningoencephalitis. This saki likely ingested environmental L. monocytogenes, which resulted in disease that may have been facilitated by pre-existing co-morbidities and age.


Assuntos
Listeria monocytogenes , Listeriose , Pitheciidae , Animais , Surtos de Doenças , Feminino , Listeria monocytogenes/genética , Listeriose/epidemiologia , Listeriose/microbiologia , Listeriose/veterinária , Tipagem de Sequências Multilocus/veterinária , Pitheciidae/genética
20.
Pol J Microbiol ; 71(1): 63-71, 2022 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-35635167

RESUMO

In order to clarified characteristics and function of internalin G (inlG) in Listeria monocytogenes ATCC®19111 (1/2a) (LM), the immune protection of the inlG was evaluated in mice, the homologous recombination was used to construct inlG deletion strains, and their biological characteristics were studied by the transcriptomics analysis. As a result, the immunization of mice with the purified protein achieved a protective effect against bacterial infection. The deletion strain LM-AinlG was successfully constructed with genetic stability. The mouse infection test showed that the virulence of LM was decreased after the deletion of the inlG gene. The deletion strain showed enhanced adhesion to and invasion of Caco-2 cells. Compared to the wild strain, 18 genes were up-regulated, and 24 genes were down-regulated in the LM-AinlG. This study has laid a foundation for further research on the function of inlG and the pathogenesis of LM. In this study, immunization of mice with the purified inlG protein achieved a protective effect against Listeria monocytogenes infection. The virulence of LM-ΔinlG was decreased by mouse infection. However, the adhesion and invasion ability to Caco-2 cell were enhanced. Compared to the wild strain, 18 genes were up-regulated, and 24 genes were down-regulated in the LM-ΔinlG. This study has laid a foundation for further study of the function of the inlG and the listeriosis.


Assuntos
Listeria monocytogenes , Listeriose , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Células CACO-2 , Humanos , Listeria monocytogenes/genética , Listeriose/microbiologia , Camundongos , Virulência/genética
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