Biofilms are widespread in nature and constitute an important strategy implemented by microorganisms to survive in sometimes harsh environmental conditions. They can be beneficial or have a negative impact particularly when formed in industrial settings or on medical devices. As such, research into the formation and elimination of biofilms is important for many disciplines. Several new methodologies have been recently developed for, or adapted to, biofilm studies that have contributed to deeper knowledge on biofilm physiology, structure and composition. In this review, traditional and cutting-edge methods to study biofilm biomass, viability, structure, composition and physiology are addressed. Moreover, as there is a lack of consensus among the diversity of techniques used to grow and study biofilms. This review intends to remedy this, by giving a critical perspective, highlighting the advantages and limitations of several methods. Accordingly, this review aims at helping scientists in finding the most appropriate and up-to-date methods to study their biofilms.
- MeSH
- bakteriální adheze MeSH
- biofilmy * růst a vývoj MeSH
- databáze faktografické MeSH
- design vybavení MeSH
- hybridizace in situ fluorescenční MeSH
- laboratoř na čipu MeSH
- mikrobiologické techniky přístrojové vybavení metody MeSH
- mikroskopie metody MeSH
- molekulární biologie metody MeSH
- počítačové zpracování obrazu metody MeSH
- software MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
UNLABELLED: An understanding of adherence ability is crucial in many areas, for example, in research on biofilms, evaluation of probiotics or in biotechnology. In all these analyses, the reproducible washing is very important in the prevention of false results. During washing, the force, direction of the flow, position of the pipette tip, number of washing cycles, type of washing solution and the way of removing the washing solution can be sources of inappropriate stress to attached cells. To overcome these problems, we here propose the use of high mass density solutions as flotation agents. As the density of bacteria is lower than that of the flotation solutions, nonattached or weakly attached bacteria are moved to the surface due to hydrostatic force. Caesium chloride, ammonium nitrate and sodium diatrizoate solutions, which are commonly used as FAs, were compared with a standard method of rinsing. Several concentrations of agents were used to investigate the optimal concentration and influence of hydrostatic pressure on adhered micro-organisms. We show that flotation is a rapid method for distinguishing between adhered and weakly attached or loosed cells with reproducible results. Due to its range of possible mass density concentration, the best FA was shown to be caesium chloride. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study that suggests using flotation agents to separate planktonic from adhered bacteria. When a high-density solution is used, buoyancy of bacteria ensures their segregation in the solution. Flotation agents could be used instead of washing procedure, which is inaccurate and hardly reproducible. High-density flotation agents could be used for more precise evaluation of bacterial adherence in many assays, such as research of biofilms or evaluation of probiotics.
The ability of bacteria to bind different compounds and to adhere to biotic and abiotic surfaces provides them with a range of advantages, such as colonization of various tissues, internalization, avoidance of an immune response, and survival and persistence in the environment. A variety of bacterial surface structures are involved in this process and these promote bacterial adhesion in a more or less specific manner. In this review, we will focus on those surface adhesins and exopolymers in selected foodborne pathogens that are involved mainly in primary adhesion. Their role in biofilm development will also be considered when appropriate. Both the clinical impact and the implications for food safety of such adhesion will be discussed.
Conditions facilitating resistance to quaternary ammonium compounds (QACs) were investigated in Staphylococcus aureus SK982 exposed to benzalkonium chloride (BAC; a member of QACs) under various circumstances. S. aureus SK982 carrying the qacA gene encoding for resistance to QACs was grown in the presence of stable or gradually increasing concentrations of BAC, or it was exposed to this antiseptic in the exponential phase of growth. Bacteria cultivated in the highest BAC concentrations that did not retard their growth comparing to the untreated control were subjected to real-time quantitative polymerase chain reaction analysis for relative expression of the efflux genes qacA and norA. Under such conditions, S. aureus SK982 tolerated a relatively low stable concentration of BAC (1.22 mg/L) when compared with a gradually increasing antiseptic concentration (tolerance of 4.88 mg/L). However, in both cases, qacA expression was not significant. The culture exposed in the exponential phase of growth tolerated the highest concentration of BAC (9.76 mg/L) as also accompanied by significant overexpression of qacA. Expression of norA was relatively low regardless of the conditions tested. It seems that under the short-term conditions, the phase of bacterial growth is more important for the expression of BAC resistance than the capability to adapt to this antiseptic. This study provides a deeper insight into the relevance of the qac genes in conferring resistance to QACs.
- MeSH
- antibakteriální látky aplikace a dávkování farmakologie MeSH
- bakteriální léková rezistence genetika MeSH
- bakteriální proteiny genetika MeSH
- benzalkoniové sloučeniny aplikace a dávkování farmakologie MeSH
- kvantitativní polymerázová řetězová reakce MeSH
- membránové transportní proteiny genetika MeSH
- mikrobiální testy citlivosti MeSH
- proteiny spojené s mnohočetnou rezistencí k lékům genetika MeSH
- regulace genové exprese u bakterií MeSH
- Staphylococcus aureus účinky léků genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The occurrence of staphylococci and enterococci expressing increased resistance to erythromycin (ERY) and, in particular, to macrolide-lincosamide-streptogramin B (MLS(B) ) antibiotics was investigated in dairy cattle, pigs and turkeys. Three hundred rectal (cloacal) swabs of each animal species were examined. A total of 120 and 71 staphylococci and enterococci, respectively, with increased resistance to ERY were identified. These were most frequent in turkeys (42.3% of positive animals), followed by pigs and dairy cattle (6.7% and 6.0% of positive animals, respectively). Similarly, MLS(B) -resistant isolates colonized predominantly turkeys (29.7% of animals), while their occurrence in pigs and dairy cattle was only sporadic (0.8% of animals). At least one of the erm genes encoding for MLS(B) resistance was found in 56.7% and 69.0% of staphylococci and enterococci, respectively. The erm(C) gene prevailed in staphylococci while the erm(B) gene was predominant in enterococci. Macrolide efflux genes msr(A) and msr(C) were also frequent in staphylococci and enterococci, respectively. Macrolide inactivation gene mph(C) occurred mainly in staphylococci. In staphylococci, methicillin resistance was rarely detected (7.5% of isolates), but resistance to telithromycin (ketolides) was frequent in both staphylococci and enterococci (89.2% and 47.9% of isolates, respectively). This study showed that turkeys represent an important source of ERY (MLS(B) )-resistant cocci. In addition, resistance to ketolides was also frequent.
- MeSH
- antibakteriální látky farmakologie MeSH
- bakteriální geny účinky léků MeSH
- bakteriální léková rezistence genetika MeSH
- bakteriální proteiny genetika metabolismus MeSH
- Enterococcus účinky léků genetika izolace a purifikace MeSH
- erythromycin farmakologie MeSH
- fenotyp MeSH
- genotyp MeSH
- krocani MeSH
- linkosamidy farmakologie MeSH
- makrolidy farmakologie MeSH
- mikrobiální testy citlivosti MeSH
- nemoci drůbeže MeSH
- prasata MeSH
- prevalence MeSH
- skot MeSH
- stafylokokové infekce farmakoterapie epidemiologie MeSH
- Staphylococcus účinky léků genetika izolace a purifikace MeSH
- streptogramin B farmakologie MeSH
- zvířata MeSH
- Check Tag
- skot MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem MeSH
Although Pasteurella multocida serogroup F has been described as an avian-adapted serogroup, it was recently found in rabbit nests in the Czech Republic. Therefore, the ability of 2 avian P. multocida serogroup F strains to induce disease in rabbits was investigated. Two groups of 18 Pasteurella-free rabbits were intranasally challenged with strains isolated from chickens and turkeys. Half of the animals in each challenge group were immunosuppressed using dexamethasone. All of the challenged rabbits exhibited clinical signs of peracute septicemic disease, ending with shock, and died or were euthanized in the terminal stages of the disease 1 to 2 d post-infection. Gross pathological changes included systemic vascular collapse and vascular leak syndrome. Hyperemia, hemorrhage, edema, inflammatory cell infiltrates, focal necrosis, and degenerative changes were observed histologically in parenchymatous organs. This is the first study directly demonstrating that avian P. multocida serogroup F strains are highly virulent in rabbits and that avian hosts cannot be excluded as a possible source of rabbit infection with serogroup F.
- MeSH
- cholera veterinární MeSH
- DNA bakterií analýza genetika MeSH
- infekce bakteriemi rodu Pasteurella mikrobiologie patologie přenos veterinární MeSH
- králíci mikrobiologie MeSH
- krocani mikrobiologie MeSH
- kur domácí mikrobiologie MeSH
- multilokusová sekvenční typizace veterinární MeSH
- nemoci drůbeže MeSH
- Pasteurella multocida klasifikace genetika izolace a purifikace patogenita MeSH
- pulzní gelová elektroforéza veterinární MeSH
- techniky typizace bakterií veterinární MeSH
- virulence MeSH
- zvířata MeSH
- Check Tag
- králíci mikrobiologie MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Geographically related Staphylococcus epidermidis isolates from human patients (n=30), dairy farms (farmers and individual raw milk from cattle, n=36) and a dairy plant (n=55) were examined for epidemiological relatedness by pulsed-field gel electrophoresis and, using in vitro methods, for the ability to produce biofilm and antimicrobial resistance. Methicillin-resistant isolates (MRSE) were also identified and characterized. Isolates from farmers and dairy cattle were found to be genetically related, while isolates from human patients were highly diverse. Some dairy plant isolates (18.2%) were closely related to those from dairy farms. Biofilm production and resistance to antimicrobial agents were most typical for isolates from human patients, of which 76.7% were MRSE. Methicillin resistance was also widespread in farm-related isolates (61.1%). This study indicates the possible transmission of S. epidermidis between cattle and farmers. Dairy products were not proven to be an important source of either human infections or methicillin-resistant strains.
- MeSH
- biofilmy růst a vývoj MeSH
- DNA bakterií genetika MeSH
- DNA fingerprinting MeSH
- fenotyp MeSH
- genotyp MeSH
- lidé MeSH
- mikrobiální testy citlivosti MeSH
- mikrobiologie životního prostředí MeSH
- mléko mikrobiologie MeSH
- molekulární epidemiologie MeSH
- pulzní gelová elektroforéza MeSH
- shluková analýza MeSH
- skot MeSH
- Staphylococcus epidermidis klasifikace genetika izolace a purifikace fyziologie MeSH
- techniky typizace bakterií MeSH
- zemědělství MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- skot MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Rabbits are often used as animal models for experimental purposes; in many cases steroid-induced immunosuppression is necessary. The aim of this study was to characterise a model of immunosuppression in rabbits, based on changes in the lymphocyte subset distribution, changes in proliferative capacity of lymphocytes and activity of neutrophils 1, 3 and 7 days after the administration of 2mg/kg dexamethasone phosphate (DXP) three times at 6-h intervals. In peripheral blood, neutrophilia and lymphopenia together with eosinopenia, monocytopenia and basopenia in the absence of leukocytosis was detected. One day after DXP administration the absolute numbers of all lymphocyte subsets decreased in the blood, whereas in bone marrow, absolute numbers of all lymphocyte subsets increased significantly, except CD79alpha(+) cells that increased only in relative numbers. The effect of DXP on lymphocytes from the spleen, mesenteric and popliteal lymph nodes was less pronounced. In the thymus, DXP led to a marked reduction of the relative and absolute numbers of CD4(+)CD8(+) thymocytes. The proliferative capacity of lymphocytes after concanavalin A stimulation was lower in the peripheral blood and spleen only on day 1, no changes were detected in lymph nodes or in bone marrow. A marked increase in proliferative capacity was detected in the thymus. Spontaneous production of reactive oxygen metabolites by neutrophils was reduced on days 1 and 3 after DXP administration. The present results demonstrate clearly that this DXP application protocol is useful for the experimental induction of relatively short-lasting immunosuppression in rabbits.
- MeSH
- dexamethason farmakologie MeSH
- financování organizované MeSH
- imunosupresiva farmakologie MeSH
- imunosupresivní léčba MeSH
- králíci MeSH
- modely nemocí na zvířatech MeSH
- náhodné rozdělení MeSH
- podskupiny lymfocytů imunologie účinky léků MeSH
- proliferace buněk účinky léků MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- zvířata MeSH
