scholarly journals Biofilm Formation among Clinical and Food Isolates ofListeria monocytogenes

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Joana Barbosa ◽  
Sandra Borges ◽  
Ruth Camilo ◽  
Rui Magalhães ◽  
Vânia Ferreira ◽  
...  
Keyword(s):  
Tissue Culture ◽  
Listeria Monocytogenes ◽  
Osmotic Stress ◽  
Environmental Conditions ◽  
Biofilm Formation ◽  
Stress Conditions ◽  
Acidic Stress ◽  
Biofilm Production ◽  
Oflisteria Monocytogenes ◽  
Clinical Cases

Objective. A total of 725Listeria monocytogenesisolates, 607 from various foods and 118 from clinical cases of listeriosis, were investigated concerning their ability to form biofilms, at 4°C during 5 days and at 37°C during 24 h.Methods. Biofilm production was carried out on polystyrene tissue culture plates. FiveL. monocytogenesisolates were tested for biofilm formation after being exposed to acidic and osmotic stress conditions.Results. Significant differences (P<0.01) between clinical and food isolates were observed. At 37°C for 24 h, most food isolates were classified as weak or moderate biofilm formers whereas all the clinical isolates were biofilm producers, although the majority were weak. At 4°C during 5 days, 65 and 59% isolates, from food and clinical cases, respectively, were classified as weak. After both sublethal stresses, at 37°C just one of the five isolates tested was shown to be more sensitive to subsequent acidic exposure. However, at 4°C both stresses did not confer either sensitivity or resistance.Conclusions. Significant differences between isolates origin, temperature, and sublethal acidic stress were observed concerning the ability to form biofilms. Strain, origin, and environmental conditions can determine the level of biofilm production byL. monocytogenesisolates.

Biofilm Formation and Associated Genes in Listeria Monocytogenes

2017 ◽  
Vol 12 (3) ◽  
Author(s):  
S. R. Warke ◽  
V. C. Ingle ◽  
N. V. Kurkure ◽  
P. A. Tembhurne ◽  
Minakshi Prasad ◽  
...  
Keyword(s):  
Public Health ◽  
Listeria Monocytogenes ◽  
Multiplex Pcr ◽  
Food Processing ◽  
Biofilm Formation ◽  
Milk Samples ◽  
Biofilm Production ◽  
Food Borne ◽  
Serious Infections ◽  
Microtiter Assay

Listeria monocytogenes, an opportunistic food borne pathogen can cause serious infections in immunocompromised individuals. L. monocytogenes is capable of producing biofilm on the surface of food processing lines and instruments.The biofilm transfers contamination to food products and impose risk to public health. In the present study biofilm producing ability of L. monocytogenes isolates were investigated phenotypically and genotypically by microtiter assay and multiplex PCR, respectively. Out of 38 L. monocytogenes isolates 14 were recovered from animal clinical cases, 12 bovine environment and 12 from milk samples. A total of 3 (21.42%) clinical, 2 (16.66%) environment and 3 (25%) milk samples respectively, revealed biofilm production in microtiter assay. Cumulative results showed that 23 (60.52%) out of 38 strains of L. monocytogenes were positive for luxS and flaA gene and 1 (2.63%) was positive only for the flaA gene.

scholarly journals Inducible Clindamycin Resistance and Biofilm Production among Staphylococci Isolated from Tertiary Care Hospitals in Nepal

2021 ◽  
Vol 13 (4) ◽  
pp. 1043-1052
Author(s):  
Sarita Manandhar ◽  
Raju Shrestha ◽  
Ratna Shova Tuladhar ◽  
Sunil Lekhak
Keyword(s):  
Tissue Culture ◽  
Biofilm Formation ◽  
Tertiary Care ◽  
Plate Method ◽  
Methicillin Resistant ◽  
Inducible Clindamycin Resistance ◽  
Biofilm Production ◽  
Resistant Strains ◽  
Tissue Culture Plate ◽  
Tertiary Care Hospitals

Resistance to antibiotics, biofilm formation and the presence of virulence factors play important roles in increased mortality associated with infection by staphylococci. The macrolide lincosamide streptogramin B (MLSB) family of antibiotics is commonly used to treat infections by methicillin-resistant isolates. Clinical failure of clindamycin therapy has been reported due to multiple mechanisms that confer resistance to MLSB. This study aims to find the incidence of different phenotypes of MLSB resistance and biofilm production among staphylococci. A total of 375 staphylococci were isolated from different clinical samples, received from two tertiary care hospitals in Nepal. Methicillin resistance was detected by cefoxitin disc diffusion method and inducible clindamycin resistance by D test, according to CLSI guidelines. Biofilm formation was detected by the tissue culture plate method and PCR was used to detect ica genes. Of the total staphylococci isolates, 161 (42.9%) were Staphylococcus aureus, with 131 (81.4%) methicillin-resistant strains, and 214 (57.1%) isolates were coagulase-negative staphylococci, with 143 (66.8%) methicillin-resistant strains. The overall prevalence of constitutive MLSB (cMLSB) and inducible MLSB (iMLSB) phenotypes was 77 (20.5%) and 87 (23.2%), respectively. Both iMLSB and cMLSB phenotypes predominated in methicillin-resistant isolates. The tissue culture plate method detected biofilm formation in 174 (46.4%) isolates and ica genes in 86 (22.9%) isolates. Among biofilm producing isolates, cMLSB and iMLSB phenotypes were 35 (20.1%) and 27 (15.5%), respectively. The cMLSB and iMLSB were 11 (12.8%) and 19 (22.1%), respectively, in isolates possessing ica genes. Clindamycin resistance in the form of cMLSB and iMLSB, especially among MRSA, emphasizes the need for routine D tests to be performed in the lab.

scholarly journals Microtiter Plate Assay for Assessment of Listeria monocytogenes Biofilm Formation

2002 ◽  
Vol 68 (6) ◽  
pp. 2950-2958 ◽  
Author(s):  
D. Djordjevic ◽  
M. Wiedmann ◽  
L. A. McLandsborough
Keyword(s):  
Listeria Monocytogenes ◽  
Crystal Violet ◽  
Biofilm Formation ◽  
Microtiter Plate ◽  
Cellular Growth ◽  
Epifluorescence Microscopy ◽  
Simple Method ◽  
Microtiter Plate Assay ◽  
Plate Assay ◽  
Biofilm Production

ABSTRACT Listeria monocytogenes has the ability to form biofilms on food-processing surfaces, potentially leading to food product contamination. The objective of this research was to standardize a polyvinyl chloride (PVC) microtiter plate assay to compare the ability of L. monocytogenes strains to form biofilms. A total of 31 coded L. monocytogenes strains were grown in defined medium (modified Welshimer's broth) at 32°C for 20 and 40 h in PVC microtiter plate wells. Biofilm formation was indirectly assessed by staining with 1% crystal violet and measuring crystal violet absorbance, using destaining solution. Cellular growth rates and final cell densities did not correlate with biofilm formation, indicating that differences in biofilm formation under the same environmental conditions were not due to growth rate differences. The mean biofilm production of lineage I strains was significantly greater than that observed for lineage II and lineage III strains. The results from the standardized microtiter plate biofilm assay were also compared to biofilm formation on PVC and stainless steel as assayed by quantitative epifluorescence microscopy. Results showed similar trends for the microscopic and microtiter plate assays, indicating that the PVC microtiter plate assay can be used as a rapid, simple method to screen for differences in biofilm production between strains or growth conditions prior to performing labor-intensive microscopic analyses.

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 Comparison of biofilm formation between non-pathogenic Listeria strains under different stress conditions

2020 ◽  
Author(s):  
Endrit Hasani ◽  
Sabrine Labidi ◽  
Csilla Mohácsi-Farkas ◽  
Gabriella Kiskó
Keyword(s):  
Listeria Monocytogenes ◽  
Food Processing ◽  
Biofilm Formation ◽  
Stress Condition ◽  
Environmental Safety ◽  
Stress Conditions ◽  
Listeria Innocua ◽  
Meat Industry ◽  
Micro Organisms ◽  
Listeria Seeligeri

AbstractMicro-organisms can attach to food surfaces and develop biofilms which present a concern in food and environmental safety. The main goal of the current study was to investigate the biofilm formation of six non-pathogenic Listeria strains under different stress conditions using a microplate assay. The effect of the weak biofilm-forming non-pathogenic Listeria strains on the biofilm formation of a strong biofilm-forming pathogenic Listeria strain (Listeria monocytogenes #8) was also examined. Listeria innocua CCM4030, Listeria innocua 2885 and Listeria seeligeri/welshimeri 292 showed the same patterns of biofilm formation with increasing NaCl concentrations from 0.05 to 15%, but all the other strains showed a continuously decreasing trend of OD595 in the same conditions. This study showed that in the case of non-pathogenic Listeria strains, higher concentrations of NaCl do not present a stress condition that enhances biofilm formation. Decrease in pH inhibited biofilm formation for all the non-pathogenic Listeria strains. The weak biofilm forming non-pathogenic Listeria strains (Listeria innocua 2885 and Listeria innocua CCM4030) overgrew the strong biofilm-forming Listeria strain (Listeria monocytogenes #8) during biofilm formation. This phenomenon could be beneficial and potentially be used as a novel control strategy to prevent the colonization of the pathogenic Listeria at food processing facilities such as in meat industry.

scholarly journals Repercussion of biofilm and antibiotic resistance in ventilator associated pneumonia

2017 ◽  
Vol 5 (10) ◽  
pp. 4419 ◽  
Author(s):  
Vinodkumar C. S. ◽  
Satish S. Patil ◽  
Arun Kumar A. ◽  
B. S. Prasad ◽  
N. K. Kalappanavar ◽  
...  
Keyword(s):  
Tissue Culture ◽  
Drug Resistance ◽  
Antibiotic Resistance ◽  
Biofilm Formation ◽  
Culture Method ◽  
Ventilator Associated Pneumonia ◽  
Biofilm Production ◽  
Group I ◽  
Bacterial Aetiology ◽  
Microbiological Techniques

Background: Ventilator associated pneumonia contributes nearly half of all cases of hospital-acquired pneumonia. Drug resistance among ventilator associated pneumonia has obligation of device withdrawal in order to achieve clinical and microbiological cure. Aim of the study was to determine the relationship between antibiotic resistance of Endotracheal tube biofilm and pulmonary pathogens in ventilator-associated pneumonia.Methods: A descriptive analytical study of 100 clinically suspected VAP patients was done. Patients were divided into group-I and Group-II based on intubation duration for 1-5 days and 6-10 days respectively. Endotracheal aspirate (ETA) was collected from clinically diagnosed cases and processed as per standard microbiological techniques. Bacterial counts ≥106 CFU/ml for quantitative cultures was considered significant. Biofilm production was detected by tissue culture plate, tube method and Congo red method. Multi-variant analysis was done to find out the association of the various factors.Results: Klebsiella pneumoniae was the predominant bacteria isolated followed by Acinetobacter baumannii. 45% of Gram negative bacteria were β lactamase producers. In Biofilm production by tissue culture method, 72% of the isolates showed either strong or moderate biofilm formation. Multivariate analysis revealed that bacteria isolated from VAP occurring after 5 days of mechanical ventilation among prior antibiotic-treated patients were resistant to all the antibiotics tested.Conclusions: Bacterial aetiology, biofilm formation and drug resistance has ramification on outcome of ventilator associated pneumonia. Hence, advised that it is crucial to remove ET tube in regular interval to prevent biofilm formation and sequential cultures to obtain the microbiological information which enables better patient care. 

scholarly journals Disinfectant Susceptibility of Biofilm Formed by Listeria monocytogenes under Selected Environmental Conditions

2019 ◽  
Vol 7 (9) ◽  
pp. 280 ◽  
Author(s):  
Krzysztof Skowron ◽  
Ewa Wałecka-Zacharska ◽  
Katarzyna Grudlewska ◽  
Piotr Gajewski ◽  
Natalia Wiktorczyk ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Environmental Conditions ◽  
Biofilm Formation ◽  
Reference Strain ◽  
Bacterial Number ◽  
Food Borne ◽  
Nacl Concentration ◽  
Working Solution ◽  
Nutrients Availability ◽  
Strain Dependent

Listeria monocytogenes is a one of the most important food-borne pathogens. Its ability to form biofilm contributes to increased resistance to disinfectants and inefficient disinfection, posing a serious threat for the food industry, and in the end the consumer. The aim of this study was the comparison of the biofilm formation ability of L. monocytogenes strains on stainless steel, under different environmental conditions (temperature, pH, NaCl concentration, nutrients availability), and the assessment of biofilm susceptibility to disinfectants. The bactericidal activity of four disinfectants in two concentrations (100% and 50% of working solution) against biofilm was conducted on four clinical strains, four strains isolated from food and one reference strain ATCC 19111. It was found that biofilm susceptibility to disinfectants was influenced by environmental conditions. Biofilm susceptibility correlated with the decrease of temperature, pH, nutrients availability and salinity of the environment. The least sensitive to disinfectants was biofilm produced at pH = 4 (the bacterial number ranged from 0.25 log CFU × cm−2 to 1.72 log CFU × cm−2) whereas the most sensitive was biofilm produced at pH = 9 (5.16 log CFU × cm−2 to 7.84 log CFU × cm−2). Quatosept was the most effective disinfectant, regardless of the conditions. In conclusion, biofilm susceptibility to disinfectants is strain-dependent and is affected by environmental conditions.

scholarly journals Role of Cold Shock Proteins in Growth of Listeria monocytogenes under Cold and Osmotic Stress Conditions

2009 ◽  
Vol 75 (6) ◽  
pp. 1621-1627 ◽  
Author(s):  
Barbara Schmid ◽  
Jochen Klumpp ◽  
Eveline Raimann ◽  
Martin J. Loessner ◽  
Roger Stephan ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Osmotic Stress ◽  
Cold Shock ◽  
Microbial Control ◽  
Nacl Stress ◽  
Stress Conditions ◽  
Control Measures ◽  
Cold Shock Protein ◽  
Osmotic Stress Tolerance ◽  
Shock Proteins

ABSTRACT The gram-positive bacterium Listeria monocytogenes is a food-borne pathogen of both public health and food safety significance. It possesses three small, highly homologous protein members of the cold shock protein (Csp) family. We used gene expression analysis and a set of mutants with single, double, and triple deletions of the csp genes to evaluate the roles of CspA, CspB, and CspD in the cold and osmotic (NaCl) stress adaptation responses of L. monocytogenes. All three Csps are dispensable for growth at optimal temperature (37°C). These proteins are, however, required for efficient cold and osmotic stress tolerance of this bacterium. The hierarchies of their functional importance differ, depending on the environmental stress conditions: CspA>CspD>CspB in response to cold stress versus CspD>CspA/CspB in response to NaCl salt osmotic stress. The fact that Csps are promoting L. monocytogenes adaptation against both cold and NaCl stress has significant implications in view of practical food microbial control measures. The combined or sequential exposure of L. monocytogenes cells to these two stresses in food environments might inadvertently induce cross-protection responses.

Phenotypic heterogeneity of Pseudomonas aeruginosa isolates in the protected nature park ‘Palić’ (Serbia)

2016 ◽  
Vol 16 (5) ◽  
pp. 1370-1377 ◽  
Author(s):  
Bojana Vujović ◽  
Smilja Teodorović ◽  
Željka Rudić ◽  
Mile Božić ◽  
Vera Raičević
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Virulence Factors ◽  
Environmental Conditions ◽  
Biofilm Formation ◽  
Phenotypic Diversity ◽  
Production Capacity ◽  
Wide Distribution ◽  
Clear Correlation ◽  
Protective Mechanism ◽  
Biofilm Production

Pseudomonas aeruginosa is a globally distributed environmental bacterium, which is also a significant opportunistic pathogen of humans, animals and plants. It is considered that wide distribution of this bacterium is connected with its most significant constitutive property to form biofilms, and that this multicellular mode of growth, predominant in nature, serves as a protective mechanism against unfavourable environmental conditions. The work presented here examines the phenotypic diversity of Pseudomonas aeruginosa environmental isolates with respect to biofilm production capacity under different environmental conditions (temperature, pH, NaCl), production of virulence factors, and motility. The purpose of this work is to present the production of two quorum sensing-regulated virulence factors (rhamnolipids and pyocyanin), explore different motility tests (swimming, swarming and twitching) and discover potential relationship between assessed phenotypic features. Obtained results delineate environmental conditions coinciding with biofilm production and suggest a high correlation between rhamnolipid production levels and biofilm formation. Rhamnolipids affect motility competence, yet only the flagellum-mediated swimming motility has significant impact on the biofilm formation potential. Although it is challenging to demarcate a definitive, clear correlation between parameters tested, rhamnolipid content appears to serve as a link between the tested phenotypic factors.

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