scholarly journals In Vitro Evaluation of Bacteriocins Activity Against Listeria monocytogenes Biofilm Formation

2015 ◽  
Vol 178 (6) ◽  
pp. 1239-1251 ◽  
Author(s):  
Anderson Carlos Camargo ◽  
Otávio Almeida Lino de Paula ◽  
Svetoslav Dimitrov Todorov ◽  
Luís Augusto Nero
Keyword(s):  
Listeria Monocytogenes ◽  
Biofilm Formation ◽  
In Vitro Evaluation

In vitro evaluation of antimicrobial potential and ability of biofilm formation of autochthonousLactobacillusspp. andLactococcusspp. isolated from traditionally made cheese from Southeastern Serbia

2018 ◽  
Vol 42 (11) ◽  
pp. e13776 ◽  
Author(s):  
Mirjana Ž. Muruzović ◽  
Katarina G. Mladenović ◽  
Milan D. Djilas ◽  
Olgica D. Stefanović ◽  
Ljiljana R. Čomić
Keyword(s):  
Biofilm Formation ◽  
In Vitro Evaluation ◽  
Antimicrobial Potential ◽  
Southeastern Serbia

Evaluation of Methods To Assess the Biofilm-Forming Ability of Listeria monocytogenes

2012 ◽  
Vol 75 (8) ◽  
pp. 1411-1417 ◽  
Author(s):  
ANTÓNIO LOURENÇO ◽  
FRANCISCO REGO ◽  
LUISA BRITO ◽  
JOSEPH F. FRANK
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
High Throughput ◽  
Biofilm Formation ◽  
High Throughput Screening ◽  
Screening Methods ◽  
Genetic Lineage ◽  
Production Lines ◽  
Genetic Characteristics

The contamination of ready-to-eat products with Listeria monocytogenes has been related to the presence of biofilms in production lines, as biofilms protect cells from chemical sanitizers. The ability of L. monocytogenes to produce biofilms is often evaluated using in vitro methodologies. This work aims to compare the most frequently used methodologies, including high-throughput screening methods based on microplates (crystal violet and the Calgary Biofilm Device) and methods based on CFU enumeration and microscopy after growth on stainless steel. Thirty isolates with diverse origins and genetic characteristics were evaluated. No (or low) correlations between methods were observed. The only significant correlation was found between the methods using stainless steel. No statistically significant correlation (P > 0.05) was detected among genetic lineage, serovar, and biofilm-forming ability. Because results indicate that biofilm formation is influenced by the surface material, the extrapolation of results from high-throughput methods using microplates to more industrially relevant surfaces should be undertaken with caution.

scholarly journals Analysis of genetic diversity and antibiotic options for clinical Listeria monocytogenes infections in China

2021 ◽  
Author(s):  
Wei Yu ◽  
Yicheng Huang ◽  
Chaoqun Ying ◽  
Yanzi Zhou ◽  
Li Zhang ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Biofilm Formation ◽  
Virulence Genes ◽  
Genomic Island ◽  
Therapeutic Option ◽  
Treatment Options ◽  
Bactericidal Effect ◽  
Time Kill ◽  
Sequence Types

Abstract Background The aim of this study was to investigate the mechanism of Listeria monocytogenes (Lm) pathogenicity and resistance. In addition, the effect of existing treatment options against Lm were systematically evaluated. Methods Six Lm isolates were collected and antimicrobial susceptibility testing of 15 antibiotics were done. Subsequently, whole genome sequencing and bioinformatics analysis were performed. Biofilm formation was evaluated by crystal violet staining. Furthermore, the effect of meropenem, linezolid, penicillin, vancomycin, trimethoprim/sulfamethoxazole were determined using the time-kill assay. Results Four sequence types (STs) were identified (ST1, ST3, ST87, ST451). Multi-virulence-locus sequence typing (MVLST) results classified ST87 isolates into cluster. All isolates were resistant to fosfomycin and daptomycin with fosX and mprF. In addition, a total of 80 virulence genes were detected and 72 genes were found in all six isolates. Seven genes associated with haemolysin were found in 26530 and 115423. However, due to lack of one genomic island including virulence genes related to flagellar synthesis, isolate 115423 produced less biofilm than five other isolates. Even all isolates were susceptible to vancomycin, the in vitro time-kill assay showed vancomycin monotherapy resulted in less than 2 log10 CFU/mL compared with the initial count. Trimethoprim/sulfamethoxazole at serum or cerebrospinal fluid concentrations had bactericidal effect against tested Lm strains at 24 h. Conclusions ST87 clone was a typical prevalent ST in clinical Lm isolates in China. Trimethoprim/sulfamethoxazole might be greater potential therapeutic option against Lm infections.

scholarly journals Packaging properties and control of Listeria monocytogenes in bologna by cellulosic films incorporated with pediocin

2013 ◽  
Vol 16 (3) ◽  
pp. 226-235 ◽  
Author(s):  
Paula Judith Pérez Espitia ◽  
Jhon Jairo Reina Pacheco ◽  
Nathália Ramos de Melo ◽  
Nilda de Fátima Ferreira Soares ◽  
Alba Manuela Durango
Keyword(s):  
Antimicrobial Activity ◽  
Water Vapor ◽  
Listeria Monocytogenes ◽  
Biofilm Formation ◽  
Testing Machine ◽  
Meat Products ◽  
Gravimetric Method ◽  
Water Vapor Permeability ◽  
Vapor Permeability

Listeria monocytogenes is a foodborne pathogen, able to survive and proliferate at refrigeration temperatures. As a result, ready-to-eat meat products have been associated with major outbreaks. Producing meat products involves lethal preservation treatments, e.g. thermal treatments. Listeria contamination, however, may be introduced when products are sliced and packaged at retail businesses or delicatessens. In Brazil, sliced bologna is very popular at retail markets. After slicing, however, bologna has a short shelf-life. The aim of this work was to study the effects of pediocin incorporation on the load at break, water vapor permeability rate and structure, by microscopic analysis, of antimicrobial cellulosic packaging. The potential application of the developed packaging for the preservation of bologna and inhibition of Listeria biofilm formation was also studied. Cellulosic antimicrobial packaging films were produced with cellulose acetate and acetone. Pediocin (commercially available concentrate ALTA TM 2341) was incorporated at 30, 40 and 50 % w/w. The load at break of films was studied using the Universal Testing Machine (Instron) at 10 °C and 25 °C. The water vapor permeability was determined by gravimetric method. A scanning electron microscope was used to study the developed packaging structure. Antimicrobial activity of films against Listeria innoucua and L. monocytogenes was tested both in vitro and in bologna samples. Results showed that values of load at break decreased with increasing concentrations of pediocin at 10 °C and 25 °C. Regarding water vapor permeability, only the control and 50 % pediocin films presented statistical difference, with the 50 % pediocin film being more permeable. In vitro tests showed antimicrobial activity against L. innocua. Cellulosic film with 50 % pediocin reduced L. monocytogenes growth on sliced bologna by 1.2 log cycles after 9 days and prevented biofilm formation on packaging and bologna surfaces. Hence, active cellulosic films made with 50 % pediocin in the form of commercially available concentrated ALTA™ 2341 have the potential of being used in a system of hurdle technologies as a final obstacle for L. monocytogenes control in bologna preservation.

scholarly journals Biofilm production by Listeria monocytogenes strains: detection with colorimetric analysis

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
P Centorame ◽  
L Iacone ◽  
R Salini ◽  
A Ciarulli ◽  
F Guidi ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Crystal Violet ◽  
Biofilm Formation ◽  
Colorimetric Analysis ◽  
Solution Versus ◽  
Crystal Violet Solution ◽  
Biofilm Production ◽  
Staining Methods

Abstract Background In literature, there are no standardized laboratory methods to detect formed biomass by colorimetric analysis. The purpose of this study was to compare three staining methods and two different wavelengths for determination of biofilm formation of Listeria monocytogenes (Lm) strains. Methods Three strains of Lm isolated from different origin were tested using 96 well polistirene plates at 12 °C and 30 °C, after incubation the wells were subjected to washing, detaching and staining with crystal violet (CV) at 0.2% and 2% (Panreac EU) in 95% ethanol and with Gram's crystal violet solution (Merck KGaA, Germany). The absorbance at 492nm and 540nm wavelengths was read using a spectrophotometer (SIRIO S, Seac, Firenze, Italia). Results The strains incubated at 12 °C displayed production of biofilm when stained with CV 2% and with Gram's crystal violet solution, both at 492 and 540 nm (with better evidence at 540 nm). If CV 0.2% was used to stain and reading at both optical densities there was evidence of weak or no biofilm production. At 30 °C, the biofilm production was displayed at both temperature and with all the stains. For all the strains and for all the conditions tested, the absorbance was greater but not proportional using the Gram's crystal violet solution, versus the CV 0,2% and CV 2%, and absorbance was higher at 540nm versus at 492nm. Conclusions Results confirmed the lack of reproducibility of each of the method used to detect and quantify the biomass produced during a biofilm formation test in vitro and the absence of ratio between the different results obtained using different CV concentration and wavelengths for reading. Key messages Biofilm production at 12 °C could not be adequately detected staining the wells with CV 0,2%. Absorbance could be influenced by the solvent in the stain used (ethanol, methanol or phenol or mixtures). To obtain data for assessment of biomass formation, being the method characterized by poor reproducibility, the laboratory should use at least the same stain and wavelength.

scholarly journals The Effect of Oleanolic and Ursolic Acids on the Hemolytic Properties and Biofilm Formation of Listeria monocytogenes

2014 ◽  
Vol 63 (1) ◽  
pp. 21-25 ◽  
Author(s):  
ANNA KUREK ◽  
KATARZYNA MARKOWSKA ◽  
ANNA M. GRUDNIAK ◽  
WIRGINIA JANISZOWSKA ◽  
KRYSTYNA I. WOLSKA
Keyword(s):  
Antibacterial Activity ◽  
Listeria Monocytogenes ◽  
Medicinal Plants ◽  
Oleanolic Acid ◽  
Biofilm Formation ◽  
Listeriolysin O ◽  
Pentacyclic Triterpenoids ◽  
Toxin Secretion ◽  
Vitro Effect

Oleanolic acid and ursolic acid are pentacyclic triterpenoids isolated from a variety of medicinal plants, which have antibacterial activity. Listeria monocytogenes is a Gram-positive facultative pathogen, being the causative agent of listeriosis. The present study was carried out to evaluate the in vitro effect of sub-inhibitory concentrations of both triterpene acids on the pathogenicity determinants of L. monocytogenes: their hemolytic activity and biofilm forming ability. Oleanolic and ursolic acids inhibited listeriolysin O activity without influencing toxin secretion. Biofilm formation, and the viability of L. monocytogenes cells in biofilms was diminished by both compounds. Thus, both acids affected L. monocytogenes virulence. It was also demonstrated that oleanolic acid bound to the peptidoglycan of L. monocytogenes and this interaction was influenced by teichoic acids.

In vitro evaluation of mercury (Hg2+) effects on biofilm formation by clinical and environmental isolates of Klebsiella pneumoniae

2019 ◽  
Vol 169 ◽  
pp. 669-677 ◽  
Author(s):  
Lívia Caroline Alexandre de Araújo ◽  
Antônio Fernando da Purificação-Júnior ◽  
Sivoneide Maria da Silva ◽  
Ana Catarina Souza Lopes ◽  
Dyana Leal Veras ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Biofilm Formation ◽  
Environmental Isolates ◽  
In Vitro Evaluation

scholarly journals Conditions of In Vitro Biofilm Formation by Serogroups of Listeria monocytogenes Isolated from Hass Avocados Sold at Markets in Mexico

Foods ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2097
Author(s):  
María Guadalupe Avila-Novoa ◽  
Velia Navarrete-Sahagún ◽  
Jean Pierre González-Gómez ◽  
Carolina Novoa-Valdovinos ◽  
Pedro Javier Guerrero-Medina ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Virulence Genes ◽  
Staining Method ◽  
Proteinase K ◽  
Epifluorescence Microscopy ◽  
Growth Media ◽  
Foodborne Illnesses

Listeria monocytogenes is an important pathogen that has been implicated in foodborne illnesses and the recall of products such as fruit and vegetables. This study determines the prevalence of virulence-associated genes and serogroups and evaluates the effects of different growth media and environmental conditions on biofilm formation by L. monocytogenes. Eighteen L. monocytogenes isolates from Hass avocados sold at markets in Guadalajara, Mexico, were characterized by virulence-associated genes and serogroup detection with PCR. All isolates harbored 88.8% actA, 88.8% plcA, 83.3% mpl, 77.7% inlB, 77.7% hly, 66.6% prfA, 55.5% plcB, and 33.3% inlA. The results showed that 38.8% of isolates harbored virulence genes belonging to Listeria pathogenicity island 1 (LIPI-1). PCR revealed that the most prevalent serogroup was serogroup III (1/2b, 3b, and 7 (n = 18, 66.65%)), followed by serogroup IV (4b, 4d–4e (n = 5, 27.7%)) and serogroup I (1/2a–3a (n = 1, 5.5%)). The assessment of the ability to develop biofilms using a crystal violet staining method revealed that L. monocytogenes responded to supplement medium TSBA, 1/10 diluted TSBA, and TSB in comparison with 1/10 diluted TSB (p < 0.05) on polystyrene at 240 h (p < 0.05). In particular, the biofilm formation by L. monocytogenes (7.78 ± 0.03–8.82 ± 0.03 log10 CFU/cm2) was significantly different in terms of TSBA on polypropylene type B (PP) (p < 0.05). In addition, visualization by epifluorescence microscopy, scanning electron microscopy (SEM), and treatment (DNase I and proteinase K) revealed the metabolically active cells and extracellular polymeric substances of biofilms on PP. L. monocytogenes has the ability to develop biofilms that harbor virulence-associated genes, which represent a serious threat to human health and food safety.

scholarly journals The biofilm formation ability of Listeria monocytogenes isolated from meat, poultry, fish and processing plant environments is related to serotype and pathogenic profile of the strains

2012 ◽  
Vol 2 (1) ◽  
pp. 12 ◽  
Author(s):  
Domenico Meloni ◽  
Roberta Mazza ◽  
Francesca Piras ◽  
Sonia Lamon ◽  
Simonetta Gianna Consolati ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Biofilm Formation ◽  
Target Genes ◽  
Microtiter Plate ◽  
Food Sources ◽  
Processing Plant ◽  
Pathogenic Potential ◽  
Microtiter Plate Assay ◽  
Processing Plants

In the present study, the relationships between serotype, pathogenic profile and <em>in vitro</em> biofilm formation of 106 <em>Listeria monocytogenes</em> strains, having no epidemiological correlation and isolated from different environmental and food sources, were analyzed. The quantitative assessment of the <em>in vitro</em> biofilm formation was carried out by using a microtiter plate assay with spectrophotometric reading (OD620). The isolates were also submitted to serogrouping using the target genes <em>lmo0737</em>, <em>lmo1118, ORF2819, ORF2110, prs</em>, and to the evaluation of the presence of the following virulence genes: <em>prfA, hlyA, rrn, inlA, inlB, iap, plcA, plcB, actA</em> and <em>mpl</em>, by multiplex PCRs. The 62% of the strains showed weak or moderate <em>in vitro</em> ability in biofilm formation, in particular serotypes 1/2b and 4b, frequently associated with sporadic or epidemic listeriosis cases. The 25% of these isolates showed polymorphism for the <em>actA</em> gene, producing a fragment of 268-bp instead of the expected 385-bp. The deletion of nucleotides in this gene seems to be related to enhanced virulence properties among these strains. Strains belonging to serotypes associated with human infections and characterized by pathogenic potential are capable to persist within the processing plants forming biofilm.

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