Preformed Bacterial Toxins

Plasma-Activated Water (PAW) as a Disinfection Technology for Bacterial Inactivation with a Focus on Fruit and Vegetables

Plasma-activated water (PAW) is generated by treating water with cold atmospheric plasma (CAP) using controllable parameters, such as plasma-forming voltage, carrier gas, temperature, pulses, or frequency as required. PAW is reported to have lower pH, higher conductivity, and higher oxygen reduction potential when compared with untreated water due to the presence of reactive species. PAW has received significant attention from researchers over the last decade due to its non-thermal and non-toxic mode of action especially for bacterial inactivation. The objective of the current review is to develop a summary of the effect of PAW on bacterial strains in foods as well as model systems such as buffers, with a specific focus on fruit and vegetables. The review elaborated the properties of PAW, the effect of various treatment parameters on its efficiency in bacterial inactivation along with its usage as a standalone technology as well as a hurdle approach with mild thermal treatments. A section highlighting different models that can be employed to generate PAW alongside a direct comparison of the PAW characteristics on the inactivation potential and the existing research gaps are also included. The mechanism of action of PAW on the bacterial cells and any reported effects on the sensory qualities and shelf life of food has been evaluated. Based on the literature, it can be concluded that PAW offers a significant potential as a non-chemical and non-thermal intervention for bacterial inactivation, especially on food. However, the applicability and usage of PAW depend on the effect of environmental and bacterial strain-based conditions and cost-effectiveness.

A botulism outbreak from roasted canned mushrooms

Food-borne botulism is a rare disease that results from ingestion of the toxins produced by Clostridium botulinum. The most common cause of the disease is the consumption of home-canned foods prepared under inappropriate conditions, especially in rural environments. In this report, a food-borne botulism outbreak potentially caused by roasted home-canned mushrooms is evaluated and the major reasons for delayed diagnosis are emphasized. The clinical features, symptoms and prognosis of the five botulism patients involved in this outbreak are presented. The clinical progressions, treatments, durations of mechanical ventilation, intensive care unit stays and hospital stays of the three patients admitted to Akdeniz University Hospital are reported.

Two-family outbreak of botulism associated with the consumption of smoked ribs in Sichuan Province, China

BACKGROUND

On September 22, 2013, two patients from Sichuan Province, China presented with symptoms of food-borne botulism, a rare but fatal illness caused by the consumption of foods containing Clostridium botulinum neurotoxins.

METHODS

Investigators reviewed the medical charts and food consumption histories, and interviewed patients and family members. Food samples and clinical specimens were tested for botulinum toxin and neurotoxin-producing Clostridium species by standard methods.

RESULTS

The first two index cases presented with cranial neuropathies and flaccid paralysis, and required mechanical ventilation. There were 12 confirmed outbreak-associated cases. Botulinum toxin type A was identified in the smoked ribs, and all of the patients had consumed the smoked ribs from the same local restaurant. The smoked ribs contained no added salt, sugar, or preservative. Botulinum toxin production likely resulted from the cold-smoking preparation method and inappropriate refrigeration.

CONCLUSIONS

Smoked ribs produced by a local restaurant, contaminated with type A botulism, was the contributor to this outbreak. The supervision of food safety should be strengthened to prevent future outbreaks in China.

The Janus faces of botulinum neurotoxin: sensational medicine and deadly biological weapon

The botulinum neurotoxins are the most dangerous toxins known (BoNTs serotypes A-G) and induce profound flaccid neuromuscular paralysis by blocking nerve-muscle communication. Poisoned motoneurons react by emitting a sprouting network known to establish novel functional synapses with the abutting muscle fiber. Understanding how our motoneurons are capable of bypassing such transmission blockade, thereby overcoming paralysis, by an astonishing display of plasticity is one of the research goals that have numerous therapeutic ramifications. This Mini-Review aims at giving a brief update on the recent discoveries regarding the molecular mechanism of botulinum toxins intoxication. Curing botulism still is a challenge once the toxin has found his way inside motoneurons. In view of the potential use of botulinum toxins as biological weapon, more research is needed to find efficient ways of curing this disease.

Clostridium botulinum and the Clinical Laboratorian: A Detailed Review of Botulism, Including Biological Warfare Ramifications of Botulinum Toxin

Objective.—This review article is designed to thoroughly familiarize all health care professionals with the history, classification, epidemiology, clinical characteristics, differential diagnosis, diagnostic evaluation (including laboratory-based testing), treatment, and prognosis of botulism. It is especially targeted toward clinical laboratorians and includes a detailed enumeration of the important clinical laboratory contributions to the diagnosis, treatment, and monitoring of patients with botulism. Finally, the bioterrorism potential for botulism is discussed, with an emphasis on the clinical laboratory ramifications of this possibility.

Data Sources.—Included medical periodicals and textbooks accessioned from computerized and manual medical literature searches. More than 1000 medical works published from the 1800s through 2003 were retrieved and reviewed in this process.

Data Synthesis.—Pertinent data are presented in textual and tabular formats, the latter including 6 tables presenting detailed information regarding the clinical parameters, differential diagnosis, diagnostic studies, laboratory testing, and therapeutic approaches to botulism.

Conclusions.—Because botulism is such a rare disease, a keen awareness of its manifestations and prompt diagnosis are absolutely crucial for its successful treatment. The bioterrorism potential of botulism adds further urgency to the need for all health care professionals to be familiar with this disease, its proper evaluation, and timely treatment; the need for such urgency clearly includes the clinical laboratory.

Detection of secreted peptides by using hypothesis-driven multistage mass spectrometry

A method is presented for the rapid detection and characterization of trace amounts of peptides secreted from microorganisms, including pheromones, virulence factors, and quorum-sensing peptides. The procedure, based on targeted multistage MS, uses a novel matrix-assisted laser desorptionionization-ion trap mass spectrometer to overcome limitations of current MS methods (limited dynamic range, signal suppression effects, and chemical noise) that impair observation of low abundance peptides from complex biological matrixes. Here, secreted peptides that are hypothesized to be present in the supernatant, but that may not be sufficiently abundant to be observed in single-stage mass spectra, are subjected to multistage MS. Highly specific fragmentation signatures enable unambiguous identification of the peptides of interest and differentiation of the signals from the background. As examples, we demonstrate the rapid (<1 min) determination of the mating type of cells in colonies of Saccharomyces cerevisiae and the elucidation of autoinducing peptides (AIPs) from supernatants of pathogenic Staphylococci. We confirm the primary structures of the agrD encoded cyclic AIPs of Staphylococcus aureus for groups I, II, and IV and provide direct evidence that the native group-III AIP is a heptapeptide (INCDFLL). We also show that the homologous peptide from Staphylococcus intermedius is a nonapeptide (RIPTSTGFF) with a lactone ring formed through condensation of the serine side chain with the C terminus of the peptide. This is the first demonstration of cyclization in a staphylococcal AIP that occurs via lactone formation. These examples demonstrate the analytical power of the present procedure for characterizing secreted peptides and its potential utility for identifying microorganisms.

Clostridium botulinum and the ophthalmologist: a review of botulism, including biological warfare ramifications of botulinum toxin

The anaerobic bacterium Clostridium botulinum causes disease by elaborating an extremely potent neurotoxin that inhibits release of acetylcholine at presynaptic nerve endings, thereby resulting in a descending flaccid paralysis and autonomic nervous system dysfunction. Possible ophthalmological effects of this neurotoxin are many and typically constitute the earliest manifestations of botulism. This review summarizes the medical literature on botulism with regard to historical perspective, epidemiology, clinical manifestations, and treatment. Ophthalmological findings of botulism are tabulated and their frequencies are provided. Finally, the bioterrorism/biologic warfare ramifications of botulinum toxin are briefly discussed.

Foodborne Illnesses

Foodborne illnesses cause a substantial human and financial burden. Despite sanitary infrastructure improvements, the incidence of foodborne bacterial infections due to non-typhoidal salmonellae (NTS), Campylobacter jejuni, and enterohemorrhagic Escherichia coli (EHEC) has risen over the last two decades. Overall, viruses account for two thirds of all foodborne illness. Most foodborne illnesses are self-limited. Supportive therapy with rehydration and the correction of electrolyte abnormalities is usually sufficient. Antibiotics play a beneficial role in the treatment of patients with certain foodborne diseases, such as listeriosis and typhoid fever, and all patients with tissue invasive or bloodstream infections. Immunocompromised patients should be treated presumptively. Antibiotics are of variable efficacy for the treatment of many infections limited to the gastrointestinal tract, and recommendations differ between pathogens. Antibiotics are generally helpful for shigellosis and cholera, and possibly beneficial for campylobacteriosis. However, antibiotics are potentially harmful in uncomplicated NTS and EHEC gastroenteritis and generally should not be used. Toxin-mediated food poisoning usually does not require specific therapy. The exception is botulism, for which botulinum antitoxin is highly efficacious if used early in the course of illness. Empiric therapy for gastroenteritis is possibly beneficial, though the magnitude of benefit is modest and incurs the risk of inadvertently treating NTS or EHEC. The choice of antibiotic should be based on local resistance patterns and the results of susceptibility testing.