USDA (food safety) 

Introduction

The genus Clostridium is comprised of gram-positive, anaerobic, spore-forming bacilli. The natural habitat of these organisms is the environment and the interstinal tracts of humans and other animals. Indeed, clostridia are ubiquitous; they are commonly found in soil, dust, sewage, marine sediments, decaying vegetation, and mud. Despite the identiciation of about 100 species of Clostridium, only a small number have been recognized as etiologic agents of medical and veterinary importance. Nonetheless, these species are associated with very serious diseases, including botulism, tetanus, anaerobic cellulitis, gas gangrene, bacteremia, pseudomembranous colitis, and clostridial gastroenteritis. As virtually all of these species have been siolated form fecal samples of apparently healthy persons, some of these isolates may be transient, rather than permanent residuents of the colonic flora (US20040115215). 

Botulism is caused by a neurotoxin produced by a member of the genus Clostridium, usually Clostridium botulinum. Organisms classified in this species produce neurotoxins distinguished by their serologic properties into toxin types A, B, C, D, E, and F. 

Particular Clostridium Species

Botulism: is a rare but serious illness caused by a toxin that attacks the body’s nerves and causes difficulty breathing, muscle paralysis, and even death. This toxin is made by Clostridium botulinum and sometimes Clostridium butyricum and Clostridium baratii bacteria. These bacteria can be spread by food and sometimes by other means. The bacteria that make botulinum toxin are found naturally in many places, but it’s rare for them to make people sick. These bacteria make spores, which act like protective coatings. Spores help the bacteria survive in the environment, even in extreme conditions. The spores usually do not cause people to become sick, even when they’re eaten. But under certain conditions, these spores can grow and make one of the most lethal toxins known.  See CDC

There are three types of botulism; 1) food borne, 2) infant and 3) wound. The botulinum toxin is a simple A-B toxin with a binding domain (B) and an enzymatic domain (A). There are 8 serotypes of botulinum toxin: A-H. The toxin binds to gangliosides receptor and is internalized. Each serotype cleaves a different part of the SNARE proteins that are responsible for the release of acetylcholine into the synapse from vesicles.

Botulism is a rare but serious illness caused by a toxin that attacks the body’s nerves. Botulism usually start with weakness of the muscles that control the eyes, face, mouth, and throat. This weakness may spread to the neck, arms, torso, and legs. Botulism also can weaken the muscles involved in breathing, which can lead to difficulty breathing and even death. See CDC

 –C. botulinum produces the most poisonous biological toxin known. Botulinal toxin blocks nerve transmission to the muscles, resulting in flaccid paralysis. When the toxin reaches airway and respiratory muscles, it results in respiratory failure that can cause death. C. botulinum used to be a major problem in home canning. Its spore is not killed by boiling and survives inadequate pressure sterilization. Mortality can be up to 25%. Symptoms are those common for neurotoxins like muscle weakness and paralysis.C. botulinum spores are carried by dust and are found on vegetables taken from the soil, on fresh fruits and on agricultural products such as honey. Under conditions favorable to the organism, the spores germinate to vegetative cells which produces toxin. Botulims disease may be goruped into 4 types based on the method of introduction of toxin into the bloodstream. Food borne botulims results form ingesting improperly preserved and inadequately heated food that contains botulinal toxin. There were 355 cases of food borne botulism in the US between 1976 and 1984. The death rate due to botulinal toxin is 12% and can be higher in particular risk groups. Wound induced botulism results form C. botulinum penetrating traumatized tissue and producing toxin that is absorbed into the bloostream. Since 1950, 30 cases of wound botulism have been reported. Inhalation botulism results when the toxin is inhaled.

–C. butyricum: C. butyricum is a soil inhabitant in various parts of the world, has been cultured from the stool of healthy children and adults, and is common in soured milk and cheeses. butyricum strains have been reported to be pathogenic, expressing virulence factors (i.e. toxins such as enterotoxins or botulinum neurotoxin; enzymes such as neuraminidase; adhesion molecules; and secretion of high levels of butyric acid).  See Casir 

Clostridium difficile (C. difficile) is a gram positive anaerobic bacillus. C dificile produces two main toxins: enterotoxin A (TcdA) and cytotoxin B (TcdB) which can play a role in diarrhaea. It is the leading casue of hospital acquired diarrhaea. (Pituch, Internat J Antimicrobial Agents, 33(S1), 2009, S42-S45)

C. difficile is considered one of the most difficult infections to treat. In patietns, CDI manifests in the colon and presents as abdominal cramping, colitis, and watery diarrhea. One of the biggest issues is the likelihood of reinfection. C. difficile casues about 500k cases of CDI in the US annually. Out of that population, 1 in 6 patietns will be reinfected within 8 weeks of recovery. This is known as recurrent CDI. (Ohaka, “Decreasing difficulty levels with mRNA-LNP vaccines” Tides Global, Oct 23, 2024). 

During the mid 1990s C difficile infection in acute care hosptials in the US was 30-40 cases per 100k. In 2001, this number rose to almost 50 and in 2005 was nearly three times the 1996 rate (31 per 100k). Of even greater concern are the increases in severe or fatal infection. In England, for example, C difficileinfection was listed as the primary cause of death for 599 patients in 199 and rote to 1998 in 2005 and 3393 in 2006. In addition, sporadic outbreaks have been reported in many hospitals. C dfficile infection predominantly affects elderly and frail hosptial and nursing home patients. However, a recent CDC advisory warns of the risk in populations not previously considered at risk. Metronidazole or oral vacomycin remain treatment of choice. (Kelly, NEJM, 359(18), 2008, 1932-1940)

The clincial spectrum of C difficile assocaited diase (CDAD) ranges form diarrhaea to severe life threatening psuedomembranous colitis. C difficile can be transmitted via personal contact or environmentally. C. difficile has more than 150 PCR ribotypes and 24 toxinotypes, has a pathogenicity locus (PaLoc) with genes encoding enterotoxin A (tcdA) and cytotoxin B (tcdB). (Kuijper, Clinical Microbiology and infection, 12(6), 2006, 2-18).

C difficile s also called “antibiotic associated colitis” due to disruption of intestinal flora by antibiotics which allows C. difficile to grow rapidly in unoccupied niches. Virulence factors include two toxins (A and B). Antibiotic associated pseudomenmbranous colitis results from the use of broad spectrum antibiotic agents such as clindamycin. These anti biotics cause diarrhea in about 10% of treated patietns and pseudomembranous colitis in about 1%. C. difficle causes antiotic assocaited diarrhea and almost all cases of pseudomembranous colitis. Psuedomembranous colitis results from the production of C dfficile toxin A and Toxin B in the olon. Toxin A probably caues most of the gastrointestinal symptoms because of its enterotoxic activity. The toxins may act synergistically and the initial pathology cased by toxin A allows toxin B to manifest its toxicity.

–Treatment of C. dificile:

—-Antibiotics:

Antibiotic –namely metronidazole and the glycopeptide vancomycin –are the current standard frist line therapy againt C. dificile infection.(Ohaka, “Decreasing difficulty levels with mRNA-LNP vaccines” Tides Global, Oct 23, 2024). Most patients with C. difficile associated disease are treated effectively with vancomysin or metronidazole. Other treatment includes tolevemer, a toxin binding polymer.

Although antiboiotics are generally effective, the disease frequently relapses, partly because antibotics kills not only C. difficile but also disrupt colonisation resistance of the gut microflora. Non-antibiotic strateis include probiotics, delibertate colonisation by non-toxigenic C. difficile strains, toxin binding agents, active immunisation, passive immunothepary with intravenous immunoglobulin, mAbs or bovine anti C diffcile whey concentrate and faecal transplantation. (Bauer, International J. of Antimicrobial Agents, 33(S1), 2009, S561-S56).

Between 15-30% of C. diffcile infected patients who initially respond to antimicrobial therapy experience rCDI. (Ohaka, “Decreasing difficulty levels with mRNA-LNP vaccines” Tides Global, Oct 23, 2024). 

—-IG or IGM or Both with Secretory component:

Simon (US2008/0260822) discloses treatment for C difficile using antigen specific polyclonal dimeric secretory IgA or pentameric secretory IgM. Because of the secretory component, it has resistance ot degradation in the gastrointestinal tract and can be used at lower doses. 

Simon (US 15/205359, published as US 2016/0319039) discloses treating C. difficile by adminstering a mixture of secretory IgA and secretory IgM.  In some embodiments the IgM or IgA is modified with secretory component. 

—-Vaccination against toxins A and B stimulates active immunity against C difficile in animals. Passive immunization as by serum antibodies agaisnt C difficile have shown to protect hamsters against C. difficile after oral adminsitration. Passive immunization with bovine antibodies has been prosed as a treatment for other infectious diseases of the gastrointestinal tract, such as diseases cuased by rotavius, enteropathogenic and enterotoxigenic E. coli, Vibrio cholerae and Cryptosporidium parvum. It has been reported that bovine IgG from the colostrum of cows vacinated with C. difficile toxoid protects hamsters agaisnt antibiotic assocaited ceditis. Human intravenous immunoglobuilin dervied from plasma donors has facilitated treatment in some pateints, specially patietns who lack circulating antibodies to the C difficile toxins. In vitro experiments have shown that polymeric IgA is superior to monomeric IgA and IgG in preventing C. dfficile toxin damainge to intestinal eptihelial cell monolayers. (Brown US 14.476,559). 

—-mRNA-LNP Vaccines:

Pro-Pro endopeptidase 1 (PPEP-1) is a highly conserved factor that modulates pathogen motility and adhersion through the cleavage of multiple factors on the C. difficle cell surface. PPEP-1 is a metalloprotease that plays a key role in bacterial mobility and gut colonization. It is secreted by all C. difficle strains, amking it an appealing target for such a heterogeneous family of pathogens. PPEP1 has another advantage which is that it is not present in other bacteria in the microbiome. This means that a vaccine should have a narrow-spectrum -C. difficile can be attacked without disrupting composition of the gut. As well as PPEP-1, C. difficile toxins TcdA and TcdB are targeted, further winnowing down the targets to toxigenic strains. Results showd that mRNA-LNP vaccines activate both CD4+ and CD8+ T cell resposnes, signifying an adaptive immune response. The vaccine could overcome deficits in host immunity to protect animals even after infection has occured. (Ohaka, “Decreasing difficulty levels with mRNA-LNP vaccines” Tides Global, Oct 23, 2024). 

C tetani is a spore forming clostridium that can become deposited in tissue through wounds. Clostridium tetani is the causative organism for the disease process known as tetanus. Clostridia are anaerobic organisms with at least 209 species and five subspecies. Clostridium tetani is one of the 4 most well-known exotoxin producing pathogens within this category. Although widespread vaccination efforts have reduced the public health threat, tetanus is a potentially fatal condition. Thus, it is important to recognize the typical clinical presentation, immediate management, and treatment of C. tetani infection. See George 

Clostridium tetani is a motile, anaerobic, spore forming bacteria (terminal spores with drum stick appearance). Vegetative cells are rod shaped, pleomorphic, and occur in pairs or short chains Footnote 1. It is Gram positive in young cultures, but becomes Gram negative upon sporulation. It is catalase and superoxide dismutase negative. It produces a potent neurotoxin tetanospasmin (TeNT), which degrades the SNARE protein required for GABA-ergic neurotransmission. 

Tetanus is caused by C. tetani, and has 4 different clinical manifestations: 1) local tetanus at the site of injury; 2) cephalic tetanus, which occurs due to head injuries or infections; 3) Generalized tetanus, which is the most common and represents 80% of the cases; 4) neonatal tetanus, which occurs in infants within 28 days of birth, due to infection of the umbilical stump. C. tetani colonizes small, non serious wounds such as a puncture wound with a splinter, and releases TeNT at the site of injury. The toxin rapidly enters the CNS through retrograde transport and blocks postsynaptic inhibition of spinal motor reflexes resulting in prolonged spasmodic contractions of the skeletal muscles. The first muscles to be affected are the neck and masseter muscles, causing rigidity of the neck and spasms of the jaw (lock jaw/trismus). See MSDS online

Because tetanus spores cannot be eliminated from the environment, and tetanus infection does not confer immunity, elimination requires ongoing active immunization with a tetanus toxoid–containing vaccine (TTCV). To protect infants from tetanus susceptibility at birth, women of reproductive age (usually 15–49 years) should be vaccinated with ≥2 doses of TTCV (TTCV2+), and immunization is recommended for undervaccinated pregnant women early in the third trimester. See MMWR

C. perfringens are ubiquitous and part of the normal flora. They produce a variety of toxins. It is a major cause of gas gangrene.

Corynebacterium: are gram-positive rods, often club-shaped, in singles, pairs (V-forms), or arranged in stacks (palisades) or irregular clusters. Some are found in the environment and many are in the normal flora (skin and mucous membranes).

–Corynebacterium diphtheriae (C. diptheriae (diphtheria)): is a non-endospore forming gram-positive club snaped bacterium.  C. diptheriae causes diptheria, a diseases which in the last 50 years has declined but has resurfaced because fewer people are getting faccinated. In Venezuela in 2017, health care was disrupted and hundreds of childen got diphteria. 

The most striking symptom of diptheria is a characteristic membrane that forms on the tonsils or pharynx. It can eventually cut of the airway, leading to death. The major virulence factor is an exotoxin encoded by a bacteriophage of C. diptheriae. Strains of the bacterium that are not lysogenized by this phage do not cause serious disease. The rlease of diptheria toxin in the blood leads to complications in distant organds, espeically myocarditis and neuritis. Neuritis affects motor nerves and may result in temperory paralysis of limbs, the soft palate and even the diaphragm.  See Wiki