Staphylococcal detection

In reconstitution experiments, the self-assembly of the pore-forming protein a-hemolysin of Staphylococcus aureus (aHL) [181-183] was examined in plain and S-layer-supported lipid bilayers. Staphylococcal aHL formed lytic pores when added to the lipid-exposed side of the DPhPC bilayer with or without an attached S-layer from B coagulans E38/vl. The assembly of aHL pores was slower at S-layer-supported compared to unsupported folded membranes. No assembly could be detected upon adding aHL monomers to the S-layer face of the composite membrane. Therefore, the intrinsic molecular sieving properties of the S-layer lattice did not allow passage of aHL monomers through the S-layer pores to the lipid bilayer [142]. 

Representatives of medium-size analytes detected by affinity biosensors based on spectroscopy of guided modes include food-safety related analytes such as staphylococcal enterotoxin B , botulinum toxin, and E. coli... 

Homola J., Dostalek J., Chen S., Rasooly A., Jiang S., Yee S.S., Spectral surface plasmon resonance biosensor for detection of staphylococcal enterotoxin B (SEB) in milk, Intern. J. Food Microbiology 2002 75 61-69. 

Shriver-Lake L.C, Shubin Y., Ligler F.S., Detection of staphylococcal enterotoxin B in spiked food samples, J. Food Protect. 2003 66 1851-1856. 

Molecular weight of the main bacterial toxins ranges from 28,000 to 150,000, which makes it possible for most sensitive SPR biosensors to measure their concentrations directly or using a sandwich assay. Examples of food safety-related toxins detected by SPR biosensors include Botulinum toxin (detection limit 2.5 pg/ml " ), . coli enterotoxin (detection limit 6 pg/ml " ) and Staphylococcal enterotoxin B (detection limit 5 ng/ml and 0.5 ng/ml for direct detection and sandwich assay, respectively" ). 

Direct detection of Staphylococcal enterotoxins B (SEB) is illustrated in Fig. 14 which shows binding of SEB to the wavelength-modulated SPR sensor surface coated with respective antibodies for five different SEB concentrations". Figure 15 shows the sensor response to binding after 30-minute SEB incubation and initial binding rate as a function of SEB... 

Figure 14. SPR sensor-based detection of Staphylococcal enterotoxin B (SEB) ...

Figure 15. Detection of Staphylococcal enterotoxin B using an SPR biosensor. Sensor response as a function of SEB concentration.

J. Homola, J. Dostalek, S. F. Chen, A. Rasooly, S. Jiang, and S. S. Yee, "Spectral Surface Plasmon Resonance Biosensor for Detection of Staphylococcal Enterotoxin B(SEB) in Milk," International Journal of Food Microbiology 75, 61-69 (2002). 

Three groups of methods have been applied to the detection of staphylococcal enterotoxins ... 

Atanassova, V., Meindl, A. and Ring, C., Prevalence of Staphylococcus aureus and staphylococcal enterotoxins in raw pork and uncooked smoked ham - a comparison of classical culturing detection and RFLP-PCR, bit. J. Food Microbiol., 68, 105-13, 2001. 

Nedelkov, D., and Nelson, R. W. (2003). Detection of staphylococcal enterotoxin B via bio-molecular interaction analysis mass spectrometry. Appl. Environ. Microbiol. 69,5212-5215. 

Slavik, R., Homola, J., and Brynda, E. (2002). A miniature fiber optic surface plasmon resonance sensor for fast detection of staphylococcal enterotoxin B. Biosens. Bioelectron. 17, 591-595. 

Chemical analysis of Mur levels has proved effective in both clinical and environmental samples, since Mur is not synthesized by eukaryotic cells. For example, it is readily detected in infected human body fluids, for example, synovial fluids from patients with staphylococcal arthritis and spinal fluids from those with pneumococcal pneumonia [7,16]. However, the most widely used method for its analysis, as an alditol acetate, is time consuming. A large number of derivatives have been tested in order to develop a simpler alternative. Unfortunately the limit of detection for these alternative approaches has not been optimal [17,18]. 

Oxacillin and cloxacillin are the most widely used isoxazolyl penicillins, the latter being particularly appropriate for treatment or prevention of bovine staphylococcal mastitis. Following intramammary treatment of a lactating cow with three successive infusions of 200 mg/48 h each of sodium cloxacillin, residues were present in milk (detection limit equal to 3 ppb) from the treated quarter for 60 h after the last infusion crossover from treated to untreated quarter was also observed (59). When cloxacillin benzathine was administered by the intramammary route to dairy cows in the dry period at a dosage of 500 mg/quarter, cloxacillin residues were present neither in serum ( 25 ppb) sampled after 5 days of drug administration nor in milk ( 5 ppb), including the milk collected... 

T. Alefantis, P. Grewal, J. Ashton, A.S. khan, J.J. Valdes and V.G. Del Vecchio, A rapid and sensitive magnetic bead-based immunoassay for the detection of staphylococcal enterotoxin B for high-through put screening, Mol. Cell. Probes, 18 (2004) 379-382. 

In one report, an array of antigens patterned on a substrate was constructed for detection of IgG antibodies from various species. This method, termed miniaturized mosaic immunoassay, is rendered possible by using the PDMS channel for patterning materials [1027]. In another report, various antibodies were patterned via the PDMS channel on a substrate for detection of three antigens FI antigen (from Yersinia pestis), staphylococcal enterotoxin B, and D-dimer (DDi, a marker of sepsis and thrombotic disorder) [1028],... 

Detection of staphylococcal enterotoxin B (SEB), a causative agent of food poisoning, was achieved by QDs conjugated with polyclonal sheep anti-SEB antibody.57 Moreover, this approach also harbors the possibility of a multiplexed immunoassay (see Fig. 12.3), which was first reported by Goldman et al.58 in 2004 four toxins of interest in food- or water-borne illnesses (cholera toxin, ricin,... 

Medina, M.B. 2003. Detection of staphylococcal enterotoxin B (SEB) with surface plasmon resonance biosensor. J Rapid Methods Autom Microbiol 11 225-243. 

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