scholarly journals Biofilm Formation and Adherence Characteristics ofListeria ivanoviiStrains Isolated from Ready-to-Eat Foods in Alice, South Africa

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Mirriam E. Nyenje ◽  
Ezekiel Green ◽  
Roland N. Ndip
Keyword(s):  
South Africa ◽  
Biofilm Formation ◽  
Food Industry ◽  
Microtiter Plate ◽  
Cross Contamination ◽  
Bacterial Strains ◽  
Cell Surface Properties ◽  
Listeria Ivanovii ◽  
Multispecies Biofilms

The present study was carried out to investigate the potential ofListeria ivanoviiisolates to exist as biofilm structures. The ability ofListeria ivanoviiisolates to adhere to a surface was determined using a microtiter plate adherence assay whereas the role of cell surface properties in biofilm formation was assessed using the coaggregation and autoaggregation assays. Seven reference bacterial strains were used for the coaggregation assay. The degree of coaggregation and autoaggregation was determined. The architecture of the biofilms was examined under SEM. A total of 44 (88%) strains adhered to the wells of the microtiter plate while 6 (12%) did not adhere. The coaggregation index ranged from 12 to 77% while the autoaggregation index varied from 11 to 55%. The partner strains ofS. aureus,S. pyogenes,P. shigelloides, andS. sonneidisplayed coaggregation indices of 75% each, whileS. Typhimurium,A. hydrophila, andP. aeruginosaregistered coaggregation indices of 67%, 58%, and 50%, respectively. The ability ofL. ivanoviiisolates to form single and multispecies biofilms at 25°C is of great concern to the food industry where these organisms may adhere to kitchen utensils and other environments leading to cross-contamination of food processed in these areas.

scholarly journals Analysis of biofilm formation by intestinal lactobacilli

2015 ◽  
Vol 61 (6) ◽  
pp. 437-446 ◽  
Author(s):  
Magdaléna Slížová ◽  
Radomíra Nemcová ◽  
Marián Mad’ar ◽  
Jana Hadryová ◽  
Soňa Gancarčíková ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Spatial Organization ◽  
Lactobacillus Reuteri ◽  
Carbon Sources ◽  
Tween 80 ◽  
Microtiter Plate ◽  
Culture Conditions ◽  
De Man ◽  
Mrs Medium

In this study, the biofilm-forming potential of intestinal Lactobacillus reuteri strains under different culture conditions was characterized by microtiter plate biofilm assays. Moreover, the spatial organization of exogenously applied L. reuteri L2/6 (a pig isolate) at specific locations in gastrointestinal tract of monoassociated mice was investigated by fluorescence in situ hybridization. We did not detect biofilm formation by tested strains in nutrient-rich de Man–Rogosa–Sharpe (MRS) medium. On the contrary, a highly positive biofilm formation was observed in medium with lower accessibility to the carbon sources and lack of salts. The results obtained confirmed the significant role of Tween 80 and the quantity and nature of the sugars in the growth medium in biofilm formation. The omission of Tween 80 in MRS medium favored the formation of biofilm. Abundant biofilm formation was detected in the presence of lactose, galactose, and glucose. However, a gradual increase in sugar concentration triggered a significant decrease in biofilm formation. In addition, conditions related to the gastrointestinal environment, such as low pH and the presence of bile and mucins, highly modulated biofilm production. This effect seems to be dependent on the specificity and properties of the medium used for cultivation. From the evidence provided by this study we conclude that the biofilm formation capacity of L. reuteri is strongly dependent on the environmental factors and culture medium used.

scholarly journals Biofilm Formation by Psychrobacter arcticus and the Role of a Large Adhesin in Attachment to Surfaces

2013 ◽  
Vol 79 (13) ◽  
pp. 3967-3973 ◽  
Author(s):  
Shannon M. Hinsa-Leasure ◽  
Cassandra Koid ◽  
James M. Tiedje ◽  
Janna N. Schultzhaus
Keyword(s):  
Biofilm Formation ◽  
Time Course ◽  
Microtiter Plate ◽  
Bacterial Attachment ◽  
Wild Type ◽  
Microtiter Plate Assay ◽  
Content Type ◽  
Reading Frame ◽  
Transposon Mutants

ABSTRACTPsychrobacter arcticusstrain 273-4, an isolate from a Siberian permafrost core, is capable of forming biofilms when grown in minimal medium under laboratory conditions. Biofilms form at 4 to 22°C when acetate is supplied as the lone carbon source and with 1 to 7% sea salt.P. arcticusis also capable of colonizing quartz sand. Transposon mutagenesis identified a gene important for biofilm formation byP. arcticus. Four transposon mutants were mapped to a 20.1-kbp gene, which is predicted to encode a protein of 6,715 amino acids (Psyc_1601). We refer to this open reading frame ascat1, for cold attachment gene 1. Thecat1mutants are unable to form biofilms at levels equivalent to that of the wild type, and there is no impact on the planktonic growth characteristics of the strains, indicating a specific role in biofilm formation. Through time course studies of the static microtiter plate assay, we determined thatcat1mutants are unable to form biofilms equivalent to that of the wild type under all conditions tested. In flow cell experiments,cat1mutants initially are unable to attach to the surface. Over time, however, they form microcolonies, an architecture very different from that produced by wild-type biofilms. Our results demonstrate that Cat1 is involved in the initial stages of bacterial attachment to surfaces.

scholarly journals Microbial biofilm: a “sticky” problem

2018 ◽  
Vol 33 (1) ◽  
Author(s):  
Arianna Pompilio ◽  
Giovanni Di Bonaventura
Keyword(s):  
Biofilm Formation ◽  
Therapeutic Strategies ◽  
Review Article ◽  
Bacterial Biofilm ◽  
Formation Mechanisms ◽  
The Past ◽  
Underlying Mechanisms ◽  
Biofilm Development ◽  
Multispecies Biofilms

Bacteria can form, on virtually any surface, single- and multispecies biofilms intrinsically resistant/tolerant to antibiotics and elusive of the host immune response. The study of bacterial biofilm development has, therefore, received great interest over the past 20 years and is motivated by the well-recognized role of these multicellular communities in infectious diseases. In this review article, we provide a synopsis of (i) biofilm formation mechanisms; (ii) biofilm clinical significance and underlying mechanisms; (iii) the current methodologies for microbiological diagnosis of biofilm-related infections; and (iv) current and future therapeutic strategies to combat biofilm-associated infections.

Influence of Temperature, Source, and Serotype on Biofilm Formation of Salmonella enterica Isolates from Pig Slaughterhouses

2015 ◽  
Vol 78 (10) ◽  
pp. 1875-1878 ◽  
Author(s):  
FRANCESCA PIRAS ◽  
FEDERICA FOIS ◽  
SIMONETTA GIANNA CONSOLATI ◽  
ROBERTA MAZZA ◽  
RINA MAZZETTE
Keyword(s):  
Optical Density ◽  
Salmonella Enterica ◽  
Biofilm Formation ◽  
Microtiter Plate ◽  
Cross Contamination ◽  
Meat Processing ◽  
Microtiter Plate Assay ◽  
Antimicrobial Resistance Profile ◽  
Density Values

Quantitative assessment of in vitro biofilm formation by 40 Salmonella enterica isolates isolated in pig abattoirs from animal and environmental sources (surfaces in contact and not in contact with meat) and classified in eight seroytpes was carried out by using a microtiter plate assay with spectrophotometric reading (optical density at 620 nm). Biofilm-forming ability was statistically correlated with the temperature of incubation (22 and 35°C), the source of the isolates, and the antimicrobial resistance profile. After incubation at 35°C, 9 isolates (22.5 %) were classified as weak biofilm producers. After incubation at 22°C, 25 isolates (62.5%) were classified as weak producers and 3 (7.5%) as moderate producers. The quantity of biofilm formed after incubation at 22°C was significantly higher (P < 0.01) than at 35°C. This result is notable because 22°C is a common temperature in meat processing facilities and in slaughterhouses. At 35°C, isolates detected from surfaces in contact with meat showed significantly higher (P < 0.1) optical density values compared to isolates from other samples, highlighting the risk of cross-contamination for carcasses and offal. No correlation was detected between quantity of biofilm and serotype or between biofilm formation and resistance to antimicrobials.

icaA Gene of Staphylococcus aureus Responds to NaCl, Leading to Increased Biofilm Formation

2018 ◽  
Vol 81 (3) ◽  
pp. 412-416 ◽  
Author(s):  
Soomin Lee ◽  
Sejeong Kim ◽  
Heeyoung Lee ◽  
Jimyeong Ha ◽  
Jeeyeon Lee ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Deletion Mutant ◽  
Microtiter Plate ◽  
Temperature Sensitive ◽  
Wild Type ◽  
Microtiter Plate Assay ◽  
Nacl Concentration ◽  
Icaa Gene

ABSTRACT The objective of this study was to elucidate the role of the icaA gene in biofilm formation of Staphylococcus aureus exposed to NaCl. The icaA-deletion mutant of S. aureus ATCC 13565 was constructed with the temperature-sensitive plasmid pIMAY. Microtiter plate assays were performed to confirm biofilm formation for both the wild type and the mutant at 0% (control), 2, 4, and 6% NaCl. The microtiter plate assay revealed that biofilm formation by the wild type increased (P < 0.05) as NaCl concentration increased, but biofilm formation of the mutant was not affected by NaCl concentration. Biofilm formation by the mutant was lower (P < 0.05) than that by the wild type. These results indicate that icaA plays an important role in biofilm formation by S. aureus when the pathogen is exposed to NaCl.

scholarly journals Isolation and Culture Dependent Characterization of Escherichia coli from the Sewage Waste Water of Lahore, Pakistan

2019 ◽  
pp. 1-13
Author(s):  
Abida Bano ◽  
Basharat Ali
Keyword(s):  
Waste Water ◽  
Drinking Water ◽  
Shiga Toxin ◽  
Biofilm Formation ◽  
Sewage Water ◽  
Cross Contamination ◽  
Bacterial Strains ◽  
E Coli ◽  
Toxin Genes ◽  
Shiga Toxin Genes

Aims: Infectious disease haemorrhagic uremic syndrome (HUS), present in sewage water, its cross contamination with drinking water may affect the community. This study was conducted to isolate the pathogenic strain of E. coli O157 from the sewage waste water of Lahore, Pakistan. The aim of this study was to evaluate biofilm formation and antibiotic susceptibility pattern for the isolated strains. Selective Hichrome EC O157 agar media was used for the isolation of E. coli. Methodology: Taxonomic status of strain was confirmed by 16S rRNA gene sequencing. Serotyping of E. coli O157 strains was accomplished by ProlexTM E. coli O157 Latex Test Reagent Kit results for O157. Bacterial strains were also evaluated for biofilm formation, toxin related genes (stx1, stx2, stx2c, stx2d) and antibiotic sensitivity. Results: Bacterial strains showed resistance against amoxicillin, tobramycin, tetracycline and nitrofurantoin antibiotics. Maximum biofilm formation was shown by strain E124 when used as monoculture. In cocultures, strains E35 and E101 were the most efficient biofilm formers. PCR amplification recorded negative results for shiga toxin genes. Conclusion: Shiga toxin genes were not present in any of the E. coli strain, from which we can suggest that our environment is free of shiga toxin genes. E. coli was present in sewage water, its cross contamination with drinking water may affect the community. Therefore, waste water should be treated properly before discarding it into the common water bodies.

A reconnaissance of tropical resources during Revolutionary years: the role of the Paris Museum d'Histoire Naturelle

1991 ◽  
Vol 18 (3) ◽  
pp. 333-362 ◽  
Author(s):  
MADELEINE LY-TIO-FANE
Keyword(s):  
South Africa ◽  
Natural History ◽  
Scientific Research ◽  
Extensive Literature ◽  
War Of Independence ◽  
Leading Role ◽  
Scientific Principles ◽  
Set Up ◽  
Joseph Ii

SUMMARY The recent extensive literature on exploration and the resulting scientific advances has failed to highlight the contribution of Austrian enterprise to the study of natural history. The leading role of Joseph II among the neutral powers which assumed the carrying trade of the belligerents during the American War of Independence, furthered the development of collections for the Schönbrunn Park and Gardens which had been set up on scientific principles by his parents. On the conclusion of peace, Joseph entrusted to Professor Maerter a world-encompassing mission in the course of which the Chief Gardener Franz Boos and his assistant Georg Scholl travelled to South Africa to collect plants and animals. Boos pursued the mission to Isle de France and Bourbon (Mauritius and Reunion), conveyed by the then unknown Nicolas Baudin. He worked at the Jardin du Roi, Pamplemousses, with Nicolas Cere, or at Palma with Joseph Francois Charpentier de Cossigny. The linkage of Austrian and French horticultural expertise created a situation fraught with opportunities which were to lead Baudin to the forefront of exploration and scientific research as the century closed in the upheaval of the Revolutionary Wars.

ROLE OF LIBRARIANS IN TEACHING INFORMATION LITERACY IN ZIMBABWEAN AND SOUTH AFRICAN UNIVERSITIES: A COMPARATIVE STUDY

Mousaion ◽  
2016 ◽  
Vol 33 (1) ◽  
pp. 23-42 ◽  
Author(s):  
Tinashe Mugwisi
Keyword(s):  
South Africa ◽  
South African ◽  
Information Literacy ◽  
Ethical Issues ◽  
University Libraries ◽  
Information And Communications Technologies ◽  
Communications Technologies ◽  
Information Skills ◽  
The University

Information and communications technologies (ICTs) and the Internet have to a large extent influenced the way information is made available, published and accessed. More information is being produced too frequently and information users now require certain skills to sift through this multitude in order to identify what is appropriate for their purposes. Computer and information skills have become a necessity for all academic programmes. As libraries subscribe to databases and other peer-reviewed content (print and electronic), it is important that users are also made aware of such sources and their importance. The purpose of this study was to examine the teaching of information literacy (IL) in universities in Zimbabwe and South Africa, and the role played by librarians in creating information literate graduates. This was done by examining whether such IL programmes were prioritised, their content and how frequently they were reviewed. An electronic questionnaire was distributed to 12 university libraries in Zimbabwe and 21 in South Africa. A total of 25 questionnaires were returned. The findings revealed that IL was being taught in universities library and non-library staff, was compulsory and contributed to the term mark in some institutions. The study also revealed that 44 per cent of the total respondents indicated that the libraries were collaborating with departments and faculty in implementing IL programmes in universities. The study recommends that IL should be an integral part of the university programmes in order to promote the use of databases and to guide students on ethical issues of information use.

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