Morphology of Salmonella enterica serovar Heidelberg typing phages

Eleven tailed phages are described. They belong to the Myoviridae, Siphoviridae, or Podoviridae families and represent the ViI, T1, T5, Jersey, N4, and P22 species of enterobacterial phages. Morphology is correlated with host range.     

Characterization of Salmonella enterica serovar Heidelberg from Turkey-Associated Sources

Salmonella enterica serovar Heidelberg strains are frequently associated with food-borne illness, with recent isolates showing higher rates of resistance to multiple antimicrobial agents. One hundred eighty S. enterica serovar Heidelberg isolates, collected from turkey-associated production and processing sources, were tested for antimicrobial susceptibility and compared by pulsed-field gel electrophoresis (PFGE) and plasmid profile analysis. The potential for the transfer of resistance between strains was studied by conjugation experiments. PFGE analysis using XbaI digestion identified eight clusters (based on 90% similarity), with the largest containing 71% of the isolates. Forty-two percent of the isolates were resistant to at least 1 of the 15 antimicrobial agents tested, and 4% of the isolates were resistant to 8 or more antimicrobial agents. Resistances to streptomycin (32%), tetracycline (30%), and kanamycin (24%) were most commonly detected. Interestingly, the XbaI PFGE profiles of selective multidrug-resistant strains (n = 22) of S. enterica serovar Heidelberg from turkey-associated sources were indistinguishable from the predominant profile (JF6X01.0022) detected in isolates associated with human infections. These isolates were further differentiated into seven distinct profiles following digestion with the BlnI enzyme, with the largest cluster comprising 15 isolates from veterinary diagnostic and turkey processing environments. Conjugation experiments indicated that resistance to multiple antimicrobial agents was transferable among strains with diverse PFGE profiles.     

Defined Minimal Growth Medium for Acanthamoeba polyphaga

Nutritional requirements of Acanthamoeba polyphaga (strain PD) were compared to those reported for A. castellanii. Although A. polyphaga and A. castellanii have essentially the same minimal amino acid requirements–arginine, methionine, leucine, isoleucine, and valine–A. polyphaga cannot utilize acetate as sole carbon source, but A. castellanii can if the medium is supplemented with glycine.     

Defined Liquid Minimal Medium for Caryophanon latum

A defined medium has been developed for the trichome-forming bacterium, Caryophanon latum. Acetate is the main carbon and energy source, and either N-glutamate, or N-NH(4) can be used as the nitrogen source.     

Development of a Synthetic Minimal Medium for Listeria monocytogenes

A defined solid and liquid minimal medium, HTM, which contained methionine and cysteine as the sole amino acids, was developed for Listeria monocytogenes. Complex broth-grown L. monocytogenes had to adapt to HTM by inducing amino acid biosyntheis. HTM is the simplest minimal medium available for growth of L. monocytogenes.     

Biosynthesis During Recovery of Heat-Injured Salmonella typhimurium

Salmonella typhimurium 7136 incorporated label from glucose-U-(14)C into nucleic acids, lipids, and pool material during recovery from heat injury. There was very little incorporation of label into protein during recovery.     

Biodegradation of Gossypol by Mixed Fungal Cultures in Minimal Medium

The fungal cultures, namely – Pleurotus sajor-caju MTCC 1806, Saccharomyces cerevisiae MTCC 6933 and Candida tropicalis MTCC 1406 and their combinations, C. tropicalis + S. cerevisiae, P. sajor-caju + S. cerevisiae and C. tropicalis + P. sajor-caju were grown in minimal medium containing 100 ppm of gossypol as the sole carbon and energy source. The culture supernatants of C. tropicalis + S. cerevisiae and P. sajor-caju + S. cerevisiae had low residual gossypol levels of 29 and 25 ppm, respectively. In the present study, we attempted to isolate gossypol-degrading enzyme and biodegraded gossypol from the culture supernatants of C. tropicalis + S. cerevisiae and P. sajor-caju + S. cerevisiae. The specific activity of laccase in the purified enzyme extracts of the C. tropicalis + S. cerevisiae and P. sajor-caju + S. cerevisiae treated samples was 425 and 224 U/mg, respectively. In SDS-PAGE, the gossypol-degrading enzyme was revealed as 3 bands of molecular weights ranging from 45 to 66 kDa. The characterization of biodegraded gossypol by FTIR analysis showed a reduction in aldehydes (C-H) stretches in samples treated with fungi. Mass spectrometry analysis revealed that the monoisotopic mass of the biodegraded gossypol was 474 g/mol.     

Vertical Ascending Electrophoresis of Cells with a Minimal Stabilizing Medium

Abstract

Vertical fractionation of a mixture of fixed horse and human red blood cells layered over a stabilizing support medium was done to give a valid comparison with proposed space experiments. In particular, the effects of sample thickness and concentration on zone migration rate were investigated. Electrophoretic mobilities of horse and human cells calculated from zone migration rates were compatible with those obtained by micro electrophoresis. Complete cell separation was observed when low power and effective cooling were employed.     

Lysogenic phage in Salmonella enterica serovar Heidelberg (Salmonella heidelberg): Implications for organism tracing

Abstract A phage typing system using a group of 11 closely related phage (as judged by Southern analysis and restriction fragment length polymorphism analysis) was able to distinguish at least six phage types in Salmonella heidelberg of human and animal origin. Restriction fragment length polymorphism analysis using cosmid probes from S. heidelberg confirmed that most S. heidelberg isolates belong to a single 'clonal' group. Southern analysis using DNA isolated from each of the testing phage group showed that phage types 4, 5 and 6 carry closely related endogenous or lysogenic phage. Induction of a lysogenic phage Hlp-4 (Heidelberg lysogenic phage) from type 4 could become lysogenic and convert phage types 1 and 3 to phage type 4 and phage type 5 to a non-typable phenotype.     

Recovery of Bacteriophage from Contaminated Chilled and Frozen Samples of Edible West Coast Crabs

Edible West Coast crabs (Cancer magister and C. antennarius) were contaminated with bacteriophage and then held in a chilled or frozen state. Results indicated a significant survival of virus regardless of storage conditions.     

Enrichment Medium for Selection of Salmonella from Fish Homogenate

A new liquid medium, called “dulcitol selenite enrichment,” has been developed for the detection and enumeration of Salmonella in foods. The medium is not only highly selective in enriching Salmonella and inhibiting completely or appreciably other extraneous organisms commonly found in seafoods, but is also highly sensitive in recovering as low as 2 to 7 cells of Salmonella, even in the presence of large numbers (10⁴ to 10⁶ cells) of mixed flora common to these foods. The addition of seafood material does not seem to interfere with the sensitivity, selectivity, or productivity of the medium. Even physiologically debilitated cells of Salmonella were enriched well enough in this medium to be detected easily.     

Development of a Defined Minimal Medium for the Growth of Edwardsiella ictaluri

In this report, a complete defined medium and a minimally defined medium are described for Edwardsiella ictaluri. The complete defined medium consists of 46 individual components, including a basal salt solution, glucose, magnesium sulfate, iron sulfate, six trace metals, four nucleotides, 10 vitamins, and 19 amino acids. This medium supports growth in broth and on solid media. Optimal growth at 30(deg)C was obtained at pH 7.0, and at an osmolality of 390 mosmol/kg of H(inf2)O, with a glucose concentration of 4 g/liter. The defined minimal medium reduces the 46 components of the complete medium to eight essential components, including the basal salt solution, glucose, magnesium sulfate, pantothenic acid, and niacinamide. In addition, specific amino acids that depend on the specific requirements of the individual strains of E. ictaluri are added.     

Plating Medium for Differentiating Salmonella arizonae from Other Salmonellae

A differential plating medium developed for isolation of Salmonella arizonae produces a uniform reaction for both lactose-negative and -positive S. arizonae and differentiates S. arizonae from other salmonellae.     

Selective Plating Medium for Quantitative Recovery of Food-Borne Listeria monocytogenes

[This corrects the article on p. 167 in vol. 56.].     

Chemically Defined Minimal Medium for Growth of the Anaerobic Cellulolytic Thermophile Clostridium thermocellum

A minimal chemically defined medium has been developed for Clostridium thermocellum. The growth factors required are biotin, pyridoxamine, vitamin B₁₂, and p-aminobenzoic acid.     

A New Methodology for Differentiation and Typing of Closely Related Salmonella enterica serovar Heidelberg Isolates

This study describe the use of a combination of two recently proposed typing approaches, multiple amplification of prophage locus typing (MAPLT) and multiple-locus variable-number tandem-repeat analysis (MLVA) for subdividing within Salmonella enterica serovar Heidelberg (S. Heidelberg). The combined typing method was compared with pulsed-field gel electrophoresis (PFGE) by Simpson’s index of diversity (DI). PFGE was shown to have a DI?=?0.84 and was poor at differentiation of the predominant PT1 (Phage Type 1) phenotype. In comparison, the combined MAPLT/MLVA method comprising 3 MLVA and 9 MAPLT primer pairs provided a higher differentiating ability DI?=?0.92. More importantly, the combined methodology was found to be superior in the differentiation of the predominant PT1 isolates. In conclusion, this study demonstrated the potential of the rapid and simple amalgamated MAPLT/MLVA approach in determining transmission of isolates of clonal phage type groups from various environmental sources to humans.     

Recovery of sublethally heat-injured Salmonella typhimurium on supplemented plating media.

The efficacy of 32 additives to Levine eosin-methylene blue-salts agar medium (EMBS) for the recovery of sublethally heat-injured Salmonella typhimurium was evaluated. In order of decreasing effectiveness, lactate, mannitol, and alpha-glycerophosphate mediated 90% or more recovery of injured cells; similar levels of recovery were obtained on EMBS supplemented with 1% (wt/vol) tryptic soy broth, protease peptone, or plate count agar. Other additives showed little or no capacity for repair or strongly inhibited heated and nonheated cell suspensions. Conditions of growth and storage before heat treatment were also found to markedly affect susceptibility to heat injury.