Detection and identification of methicillin resistant and sensitive strains of Staphylococcus aureus using tandem measurements.

Discrimination of methicillin resistant (MRSA) and sensitive (MSSA) strains of Staphylococcus aureus, was achieved by the specially selected lytic bacteriophage with a wide host range of S. aureus strains and a penicillin-binding protein (PBP 2a) specific antibody. A quartz crystal microbalance with dissipation monitoring (QCM-D) was employed to analyze bacteria-phage interactions.

Natural biopolymer for preservation of microorganisms during sampling and storage.

Stability of microbial cultures during sampling and storage is a vital issue in various fields of medicine, biotechnology, food science, and forensics. We have developed a unique bacterial preservation process involving a non-toxic, water-soluble acacia gum polymer that eliminates the need for refrigerated storage of samples. The main goal of this study is to characterize the efficacy of acacia gum polymer for preservation of pathogenic bacteria (Bacillus anthracis and methicillin-resistant Staphylococcus aureus-MRSA) on different materials, used for swabbing and filtration: cotton, wool, polyester, rayon, charcoal cloth, and Whatman paper.

Effects of surface functionalization on the surface phage coverage and the subsequent performance of phage-immobilized magnetoelastic biosensors.

One of the important applications for which phage-immobilized magnetoelastic (ME) biosensors are being developed is the wireless, on-site detection of pathogenic bacteria for food safety and bio-security. Until now, such biosensors have been constructed by immobilizing a landscape phage probe on gold-coated ME resonators via physical adsorption. Although the physical adsorption method is simple, the immobilization stability and surface coverage of phage probes on differently functionalized sensor surfaces need to be evaluated as a potential way to enhance the detection capabilities of the biosensors.

Preservation of bacteria in natural polymers.

A new inexpensive and simple method for preserving microorganisms has been developed. Natural polymers of acacia gum and pullulan were used to preserve model bacteria Escherichia coli and Bacillus subtilis via immobilization and storage under various conditions. Formulation of E.

Sequential detection of Salmonella typhimurium and Bacillus anthracis spores using magnetoelastic biosensors.

Multiple phage-based magnetoelastic (ME) biosensors were simultaneously monitored for the detection of different biological pathogens that were sequentially introduced to the measurement system. The biosensors were formed by immobilizing phage and 1mg/ml BSA (blocking agent) onto the magnetoelastic resonator's surface. The detection system included a reference sensor as a control, an E2 phage-coated sensor specific to S.

The effect of salt and phage concentrations on the binding sensitivity of magnetoelastic biosensors for Bacillus anthracis detection.

This article presents an investigation of the effect of salt and phage concentrations on the binding affinity of magnetoelastic (ME) biosensors. The sensors were fabricated by immobilizing filamentous phage on the ME platform surface for the detection of Bacillus anthracis spores. In response to the binding of spores to the phage on the ME biosensor, a corresponding decrease occurs in resonance frequency.

Phage immobilized magnetoelastic sensor for the detection of Salmonella typhimurium.

In this article, a phage-based magnetoelastic sensor for the detection of Salmonella typhimurium is reported. Filamentous bacteriophage specific to S. typhimurium was used as a biorecognition element in order to ensure specific and selective binding of bacteria onto the sensor surface.

Rapid and sensitive magnetoelastic biosensors for the detection of Salmonella typhimurium in a mixed microbial population.

In this article, we report the results of an investigation into the performance of a wireless, magnetoelastic biosensor designed to selectively detect Salmonella typhimurium in a mixed microbial population. The Langmuir-Blodgett (LB) monolayer technique was employed for antibody (specific to Salmonella sp.) immobilization on rectangular shaped strip magnetoelastic sensors (2 x 0.

A magnetoelastic resonance biosensor immobilized with polyclonal antibody for the detection of Salmonella typhimurium.

Mass-sensitive, magnetoelastic resonance sensors have a characteristic resonant frequency that can be determined by monitoring the magnetic flux emitted by the sensor in response to an applied, time varying, magnetic field. This magnetostrictive platform has a unique advantage over conventional sensor platforms in that measurement is wireless and remote. A biosensor for the detection of Salmonella typhimurium was constructed by immobilizing a polyclonal antibody (the bio-molecular recognition element) onto the surface of a magnetostrictive platform.

Affinity-selected filamentous bacteriophage as a probe for acoustic wave biodetectors of Salmonella typhimurium.

Proof-in-concept biosensors were prepared for the rapid detection of Salmonella typhimurium in solution, based on affinity-selected filamentous phage prepared as probes physically adsorbed to piezoelectric transducers. Quantitative deposition studies indicated that approximately 3 x 10(10)phage particles/cm(2) could be irreversibly adsorbed for 1 h at room temperature to prepare working biosensors. The quality of phage deposition was monitored by fluorescent microscopy.

Evaluation of agar plates for direct enumeration of Campylobacter spp. from poultry carcass rinses.

Campy-Cefex, a modification of Campy-Cefex, modified charcoal cefoperazone deoxycholate (mCCDA), Karmali, CAMPY, and Campy-Line agars were evaluated for their efficiency to isolate and enumerate Campylobacter spp. from poultry carcass rinses. Campy-Cefex and its modification produced the best results but were statistically similar to CAMPY, mCCDA, and Karmali.

Landscape phage probes for Salmonella typhimurium.

We selected from landscape phage library probes that bind preferentially Salmonella typhimurium cells compared with other Enterobacteriaceae. The specificity of the phage probes for S. typhimurium was analyzed by the phage-capture test, the enzyme-linked immunosorbent assay (ELISA), and the precipitation test.

Specific and selective biosensor for Salmonella and its detection in the environment.

The specific and selective detection of Salmonella typhymurium based on the use of a polyclonal antibody immobilized by the Langmuir-Blodgett method on the surface of a quartz crystal acoustic wave device was demonstrated in liquid samples. These biosensors were selective to S. typhymurium in the presence of large concentrations of Escherichia coli O157:H7.

Differences in the pathogenicity of various bacterial isolates used in an induction model for gangrenous dermatitis in broiler chickens.

A gangrenous dermatitis model was developed in broiler chickens, in which birds previously vaccinated at 14 days of age with a bursal disease virus vaccine were challenged at 4 wk of age with various bacterial combinations with the combination of subcutaneous and intramuscular injection. Gangrenous dermatitis lesions were not produced in birds injected with one of the Staphylococcus aureus isolates, either alone or in combination with various Clostridium septicum isolates. Other S.

Rapid and sensitive biosensor for Salmonella.

The rapid and sensitive detection of Salmonella typhymurium based on the use of a polyclonal antibody immobilized by the Langmuir-Blodgett method on the surface of a quartz crystal acoustic wave device was demonstrated. The binding of bacteria to the surface changed the crystal resonance parameters; these were quantified by the output voltage of the sensor instrumentation. The sensor had a lower detection limit of a few hundred cells/ml, and a response time of < 100 s over the range of 10(2)-10(10) cells/ml.

Molecular subtyping of Clostridium perfringens by pulsed-field gel electrophoresis to facilitate food-borne-disease outbreak investigations.

Clostridium perfringens is a common cause of food-borne illness. The illness is characterized by profuse diarrhea and acute abdominal pain. Since the illness is usually self-limiting, many cases are undiagnosed and/or not reported.

Specific identification of Campylobacter fetus by PCR targeting variable regions of the 16S rDNA.

Campylobacter fetus is recognized as a human and animal pathogen. The isolation and differentiation of C. fetus in diagnostic laboratories is hindered by its relatively slow growth and lack of distinguishing biochemical characteristics.

Viability of Bordetella pertussis in four suspending solutions at three temperatures.

We studied the survival of Bordetella pertussis in four suspending solutions (Casamino Acids broth, deionized water, phosphate-buffered saline, and serum inositol), subjected to three storage temperatures (4, -20, and -70 degrees C) and two freezing methods (direct freezing and fast-freezing in an ethanol-dry-ice bath). Recovery rates were higher for longer periods for suspensions stored at -70 degrees C than those stored at -20 or 4 degrees C. Serum inositol showed the highest recovery rates for all experimental conditions, followed by Casamino Acids, deionized water, and phosphate-buffered saline.

Use of multiple molecular subtyping techniques to investigate a Legionnaires' disease outbreak due to identical strains at two tourist lodges.

A multistate outbreak of Legionnaires' disease occurred among nine tour groups of senior citizens returning from stays at one of two lodges in a Vermont resort in October 1987. Interviews and serologic studies of 383 (85%) of the tour members revealed 17 individuals (attack rate, 4.4%) with radiologically documented pneumonia and laboratory evidence of legionellosis.

Rapid immunodot technique for identifying Bordetella pertussis.

We developed and evaluated a rapid test with monoclonal antibodies to identify cultures of Bordetella pertussis. Samples of 5 microliters of cells suspended in formalin-saline were dried onto a nitrocellulose disk. The disk was placed in a filtration device, and 5-microliters volumes of murine monoclonal antibody directed against B.

Incubation of water samples containing amoebae improves detection of legionellae by the culture method.

Some protozoans isolated from aquatic habitats, including domestic water supplies, can support the intracellular replication of autochthonous legionellae in vitro. We studied the effect of incubating water samples containing amoebae on the sensitivity of culture for legionellae. Samples collected during investigations of legionellosis epidemics and shown by conventional culture procedures to contain amoebae, but not legionellae, were incubated at 35 degrees C and replated.

Communitywide outbreak of Legionnaires' disease associated with a grocery store mist machine.

From 10 October through 13 November 1989, 33 patients were hospitalized with legionnaires' disease in Bogalusa, Louisiana. A case-control study revealed case-patients were more likely than controls to have shopped at grocery store A (93% vs. 52%; odds ratio [OR], 11.

Characterization of an axenic strain of Hartmannella vermiformis obtained from an investigation of nosocomial legionellosis.

A free-living amoeba identified as Hartmannella vermiformis was isolated from a water sample obtained during an investigation of nosocomial legionellosis. Hartmannella vermiformis is known to support the intracellular multiplication of Legionella pneumophila. This strain of H.

Virulence of a Legionella anisa strain associated with Pontiac fever: an evaluation using protozoan, cell culture, and guinea pig models.

Legionella anisa and the amoeba Hartmannella vermiformis were isolated from an indoor fountain implicated as the infectious reservoir in an outbreak of Pontiac fever. We evaluated the ability of this strain of L. anisa to multiply in cultures of an amoeba (H.

Increased recovery of Legionella micdadei and Legionella bozemanii on buffered charcoal yeast extract agar supplemented with albumin.

The recovery of Legionella micdadei and L. bozemanii serogroups 1 and 2 from infected guinea pig spleens was evaluated by using two culture media: buffered charcoal yeast extract agar with 0.1% alpha-ketoglutarate (BCYE alpha) and the same medium supplemented with 1% bovine serum albumin (ABCYE alpha).