σB affects biofilm formation under the dual stress conditions imposed by adding salt and low temperature in Listeria monocytogenes

2014 ◽  
Vol 52 (10) ◽  
pp. 849-855 ◽  
Author(s):  
Jin-Ju Lee ◽  
Gilho Lee ◽  
Ji-Hyun Shin
2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Joana Barbosa ◽  
Sandra Borges ◽  
Ruth Camilo ◽  
Rui Magalhães ◽  
Vânia Ferreira ◽  
...  

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.


Author(s):  
Endrit Hasani ◽  
Sabrine Labidi ◽  
Csilla Mohácsi-Farkas ◽  
Gabriella Kiskó

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.


Author(s):  
S. R. Warke ◽  
V. C. Ingle ◽  
N. V. Kurkure ◽  
P. A. Tembhurne ◽  
Minakshi Prasad ◽  
...  

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.


2013 ◽  
Vol 80 (1) ◽  
pp. 97-103 ◽  
Author(s):  
Dan Li ◽  
Yukie Shibata ◽  
Toru Takeshita ◽  
Yoshihisa Yamashita

ABSTRACTAStreptococcus mutansmutant defective in aciduricity was constructed by random-insertion mutagenesis. Sequence analysis of the mutant revealed a mutation ingidA, which is known to be involved in tRNA modification inStreptococcus pyogenes. Complementation ofgidAbyS. pyogenesgidArecovered the acid tolerance ofS. mutans. Although thegidA-inactivatedS. pyogenesmutant exhibited significantly reduced expression of multiple extracellular virulence proteins, theS. mutansmutant did not. On the other hand, thegidAmutant ofS. mutansshowed reduced ability to withstand exposure to other stress conditions (high osmotic pressure, high temperature, and bacitracin stress) besides an acidic environment. In addition, loss of GidA decreased the capacity for glucose-dependent biofilm formation by over 50%. This study revealed thatgidAplays critical roles in the survival ofS. mutansunder stress conditions, including lower pH.


2016 ◽  
Vol 79 (7) ◽  
pp. 1143-1153 ◽  
Author(s):  
JOHN C. FRELKA ◽  
GORDON R. DAVIDSON ◽  
LINDA J. HARRIS

ABSTRACT After harvest, inshell walnuts are dried using low-temperature forced air and are then stored in bins or silos for up to 1 year. To better understand the survival of bacteria on inshell walnuts, aerobic plate counts (APCs) and Escherichia coli–coliform counts (ECCs) were evaluated during commercial storage (10 to 12°C and 63 to 65% relative humidity) over 9 months. APCs decreased by 1.4 to 2.0 log CFU per nut during the first 5 months of storage, and ECCs decreased by 1.3 to 2.2 log CFU per nut in the first month of storage. Through the remaining 4 to 8 months of storage, APCs and ECCs remained unchanged (P &gt; 0.05) or decreased by &lt;0.15 log CFU per nut per month. Similar trends were observed on kernels extracted from the inshell walnuts. APCs and ECCs were consistently and often significantly higher on kernels extracted from visibly broken inshell walnuts than on kernels extracted from visibly intact inshell walnuts. Parameters measured in this study were used to determine the survival of five-strain cocktails of E. coli O157:H7, Listeria monocytogenes, and Salmonella inoculated onto freshly hulled inshell walnuts (~8 log CFU/g) after simulated commercial drying (10 to 12 h; 40°C) and simulated commercial storage (12 months at 10°C and 65% relative humidity). Populations declined by 2.86, 5.01, and 4.40 log CFU per nut for E. coli O157:H7, L. monocytogenes, and Salmonella, respectively, after drying and during the first 8 days of storage. Salmonella populations changed at a rate of −0.33 log CFU per nut per month between days 8 and 360, to final levels of 2.83 ± 0.79 log CFU per nut. E. coli and L. monocytogenes populations changed by −0.17 log CFU per nut per month and −0.26 log CFU per nut per month between days 8 and 360, respectively. For some samples, E. coli or L. monocytogenes populations were below the limit of detection by plating (0.60 log CFU per nut) by day 183 or 148, respectively; at least one of the six samples was positive at each subsequent sampling time by either plating or by enrichment.


2013 ◽  
Vol 165 (3) ◽  
pp. 259-264 ◽  
Author(s):  
Sachin R. Kadam ◽  
Heidy M.W. den Besten ◽  
Stijn van der Veen ◽  
Marcel H. Zwietering ◽  
Roy Moezelaar ◽  
...  

Microbiology ◽  
2010 ◽  
Vol 156 (12) ◽  
pp. 3782-3790 ◽  
Author(s):  
Stijn van der Veen ◽  
Tjakko Abee

The food-borne pathogen Listeria monocytogenes is able to form biofilms in food processing environments. Since biofilms are generally difficult to eradicate during clean-up procedures, they pose a major risk for the food industry. Stress resistance mechanisms involved in L. monocytogenes biofilm formation and disinfectant resistance have, to our knowledge, not been identified thus far. In this study, we investigated the role of hrcA, which encodes the transcriptional regulator of the class I heat-shock response, and dnaK, which encodes a class I heat-shock response chaperone protein, in static and continuous-flow biofilm formation and resistance against benzalkonium chloride and peracetic acid. Induction of both hrcA and dnaK during continuous-flow biofilm formation was observed using quantitative real-time PCR and promoter reporters. Furthermore, in-frame deletion and complementation mutants of hrcA and dnaK revealed that HrcA and DnaK are required to reach wild-type levels of both static and continuous-flow biofilms. Finally, disinfection treatments of planktonic-grown cells and suspended static and continuous-flow biofilm cells of wild-type and mutants showed that HrcA and DnaK are important for resistance against benzalkonium chloride and peracetic acid. In conclusion, our study revealed that HrcA and DnaK are important for L. monocytogenes biofilm formation and disinfectant resistance.


PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257236
Author(s):  
Zong He Zhu ◽  
Abdul Sami ◽  
Qing Qing Xu ◽  
Ling Ling Wu ◽  
Wen Yin Zheng ◽  
...  

The present study was performed to evaluate the effects of seed priming. This was done by soaking the seeds of two rapeseed cultivars, namely, ZY15 (tolerant to low temperature and drought) and HY49 (sensitive to low temperature and drought), for 12 h in varying solutions: distilled water, 138 mg/L salicylic acid (SA), 300 mg/L gibberellic acid (GA), 89.4 mg/L sodium nitroprusside (SNP), 3000 mg/L calcium chloride (CaCl2), and 30 mg/L abscisic acid (ABA). Primed and non-primed seeds were left to germinate at 15°C and -0.15 MPa (T15W15) and at 25°C and 0 MPa (T25W0), respectively. The results showed that SA, GA, SNP, CaCl2, and ABA significantly improved the germination potential (GP), germination rate (GR), germination index (GI), stem fresh weight (SFW), stem dry weight (SDW), root length (RL), stem length (SL), and seed vigor index (SVI) under T15W15. For ZY15 seeds under T25W0, GA, SNP, CaCl2, and ABA priming reduced the average germination time (96% after 5 days) compared to that of the control (88% after 5 days). For ZY15 seeds under T15W15, SA, SNP, CaCl2, and ABA priming, with respect to the control and water-treated groups, shortened the average germination time (92% after 5 days) compared to that of the control (80% after 5 days). For HY49 seeds under T25W0, GA, SNP, CaCl2, and ABA priming reduced the average germination time (92% after 5 days) compared to that of the control (85% after 5 days). Similarly, for HY49 seeds under T15W15, GA priming shortened the average germination time (89% after 5 days) compared to that of the control (83% after 5 days). These priming agents increased the net photosynthesis, stomatal conductivity, and transpiration rate of rape seedlings under conditions of low temperature and drought stress, while also decreasing intercellular carbon dioxide (CO2) concentrations. Additionally, SA, GA, SNP, CaCl2, and ABA increased superoxide dismutase concentrations (SOD) and ascorbic peroxidase (APX) activities of rape seedlings under stress conditions, while decreasing catalase (CAT) and peroxidase (POD) activities in ZY15 seedlings. In HY49, which is sensitive to low temperature and drought, all priming solutions, except for SNP, led to an increase in SOD activity levels and a decrease in CAT activity levels. Overall, SA, GA, SNP, and CaCl2 increased the concentrations of indoleacetic acid (IAA), GA, ABA, and cytokinin (CTK) in seedlings under stress conditions. Moreover, compared to SA, CaCl2, and ABA, GA (300 mg/L) and SNP (300 mol/L) showed improved priming effects for ZY15 and HY49 under stress conditions.


2021 ◽  
Vol 11 ◽  
Author(s):  
Yunge Liu ◽  
Lina Wu ◽  
Jina Han ◽  
Pengcheng Dong ◽  
Xin Luo ◽  
...  

The aim of this study was to assess the efficacy of four natural antimicrobial compounds (cinnamaldehyde, eugenol, resveratrol and thymoquinone) plus a control chemical disinfectant (sodium hypochlorite) in inhibiting biofilm formation by Listeria monocytogenes CMCC54004 (Lm 54004) at a minimum inhibitory concentration (MIC) and sub-MICs. Crystal violet staining assay and microscopic examination were employed to investigate anti-biofilm effects of the evaluated compounds, and a real-time PCR assay was used to investigate the expression of critical genes by Lm 54004 biofilm. The results showed that five antimicrobial compounds inhibited Lm 54004 biofilm formation in a dose dependent way. Specifically, cinnamaldehyde and resveratrol showed better anti-biofilm effects at 1/4 × MIC, while sodium hypochlorite exhibited the lowest inhibitory rates. A swimming assay confirmed that natural compounds at sub-MICs suppressed Lm 54004 motility to a low degree. Supporting these findings, expression analysis showed that all four natural compounds at 1/4 × MIC significantly down-regulated quorum sensing genes (agrA, agrC, and agrD) rather than suppressing the motility- and flagella-associated genes (degU, motB, and flaA). This study revealed that sub-MICs of natural antimicrobial compounds reduced biofilm formation by suppressing the quorum sensing system rather than by inhibiting flagella formation.


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