Endospore-forming bacteria

Germination events of endospores How many genetic copies maintained?

1, other is dissolved

Infection rate is low in US due to active immunization programs This is not the case in developing countries where the mortality rate can be as high as 50%, many of which will be neonatal cases Diagnosis based on clinical presentation alone bc of its extreme molecular oxygen sensitivity and low number of organisms required to initiate infection

C tetani

Found in soil, GI tract of animals and humans Usually contracted by wound contamination—typically a deep cut or puncture by a contaminated object owing to the strict anaerobic nature of bacterium

C tetani

B anthracis Anthrax ... is a highly virulent strain weaponized by the former USSR for biowarfare ... strain isolated from a bovine in Texas and used by 2001 Amerithrax letter murderer ... strain lack poly-glu capsule and used as vaccine

836 Ames strain Sterne strain

Bacillus anthracis and bacillus cereus are the .../... spore-forming bacterial pathogens The strict ... spore-forming pathogens include clostridium perfringens, C tetani, C botulinum, C. difficile

Aerobic/facultative Anaerobic

C diff Develops within about a week after administration of antibiotics (clindamycin, penicillins, cephalosporins, fluoroquinolone) Ranges from acute and self-limited to chronic

Antibiotic-associated diarrhea

C diff Endosporogenesis necessitates ... for sterilization, ... for decontamination, and thorough ... of hospital rooms

Autoclaving, incineration, disinfection

Easy to isolate from tissues, observe microscopically in specimens, and cultivate in vitro No endospores seen in clinical samples bc the spores germinate to vegetative cells before toxin production Colonial morphology involves irregular borders which are adherent w slight ground glass appearance on blood agar No hemolysis Plaque formation w specific phage is esen

B anthracis

A large, gram pos, facultatively anaerobic, endospore-forming, rod-shaped bacterium Rare polypeptide capsule composed of poly-D-glutamic acid is essential for virulence

Bacillus anthracis

Humans contract it thru infected animals and contaminated animal products No person to person transmission bc bacteria reproduce in mediastinal lymphatics rather than airways Spore aggregates can be milled to such as size (INFECTIOUS AEROSOL) that the organism can be employed as agent of bioterrorism

Bacillus anthracis

Ideal microorganism for development as bioweapon due to refractory nature of its endospores an its toxigenesis

Bacillus anthracis

The natural hosts are herbivores, therefore it is a veterinary pathogen Animals most likely get it from the soil where it is ubiquitous at mesophilic temps Survives indefinitely in soil as endospores

Bacillus anthracis

Zoonotic pulm infections contracted from inhalation of endospores and involve hemorrhagic mediastinitis w pleural effusions Often accompanied by hemorrhagic meningitis

Bacillus anthracis

Incubation period of up to 60 days after spore inhalation Alveolar macrophage eventually ingest spores and transfer them to mediastinal lymph nodes where they germinate Rapid onset of non-specific, flu-like symptoms w fever, massive edema, and lymphadenopathy of mediastinal lymph nodse

Bacillus anthracis—inhalation anthrax

Clostridium botulinum Produces an A-B subunit exotoxin called ..., one of which has endopeptidase activity (...) which inactivates the proteins that regulate the release of ..., thereby blocking neurotransmission at ... ... synapses

Botulinum, botulin, acetylcholine, peripheral cholinergic

Prevention of germination by storing food at 4˚C or inactivating toxin w heat Pt is treated by monitoring resp function, ventilation support if needed, gastric lavage, chemotherapy, and trivalent or heptavalent antitoxin to inactivate unbound toxin

C botulinum

Recover does not result in protective immunity and no vaccine is currently available for widespread use Nerve endings must be regenerated over time as binding is irreversible

C botulinum

MC mode of transmission: vehicle (food-borne, airborne organism), direct contact (wound), parenteral (injection) Virulence factors: exotoxin Culture/diagnosis: culture of organism; demonstration of toxin Prevention: food hygiene; toxoid immunization available for lab professionals Treatment: antitoxin, supportive care

Clostridium botuinum

The etiologic agent of botulism Large, gram pos, anaerobic, spore-forming bacillus Spores are terminal to sub-terminal and distend the cell wall Produces the most acutely toxic biological toxic known, on CDC select agent list of potentially weaponizable microbial products

Clostridium botulinum

Gram pos, strictly anaerobic bacillus which forms endospores resistant to antibacterial factors

Clostridium difficile

Ubiquitous sewage, soil, water, and air bacterium, therefore present on all environmental surfaces Can be a human gut microbiome commensal (bad bacterium)

Clostridium difficile

May simply colonize as a commensal in the GI tract, cause a self-limiting gastroenteritis, or cause a high morbidity destruction of tissue due to the ability to produce as many as 12 exotoxins and hydrolytic enzymes presenting as gag gangrene (clostridial myonecrosis)

Clostridium perfringens

Soft tissue infections typically resulting from bacterial contamination of wounds or localized trauma Surgical debridement and high-dose chemotherapy are indicated for the most serious infections

Clostridium perfringens

A large, gram pos, anaerobic, spore-forming (terminal, distends cell wall) bacillus that is extremely sensitive to molecular oxygen (strict anaerobe)

Clostridium tetani

MC mode of transmission: parenteral, direct contact Virulence factors: tetanospasmin exotoxin Culture/diagnosis: symptomatic Prevention: tetanus toxoid immunization Treatment: combination of passive antitoxin and tetanus toxoid active immunization, supportive care

Clostridium tetani

A zoonotic disease in humans contracted from infected animals or contaminated products thru cuts or puncture wounds in skin Ulcerative lesion surrounded by vesicular ring by day 5, necrotic black eschar w redness at day 15 Systemic symptoms, lymaphdenopathy, massive edema follow if untreated Amoxicillin is drug of choice

Cutaneous anthrax

C diff ... of the antibiotic may be sufficient for mild forms, but ... or ... chemotherapy is necessary for severe diarrhea or pseudomembranous colitis Recent research has been promising for various types of ... transplantation

Discontinuation, metronidazole or vancomycin Fecal

Bacillus cereus ... gastroenteritis is caused by a heat-stable, proteolysis-resistant enterotoxin ... gastroenteritis is mediated by a heat-labile enterotoxin

Emetic Diarrheal

C diff Virulence factors include ability to survive adverse conditions due to ..., ability to grow in absence of oxygen, and production of heat-labile .... A and B which damage epithelial lining of bowel

Endosporulation Enterotoxins A and B

B anthracis Spores are resistant to 70% ... and most other antiseptics and disinfectants Immediate empirical chemotherapy w ... or ... is essential for survival Vaccines are efficacious for agricultural animals, not as effective for humans in terms of precluding infection or relapse

Ethanol Ciprofloxacin, doxycycline

Clostridium botulinum This results in a presentation referred to as ... paralysis accompanied by blurred vision, ptosis, dry mouth, dilated pupils, constipation, and abdominal pain leading to eventual dyspnea and resp failure

Flaccid paralysis

C botulinum Foodborne diagnosis is reached upon detection of toxin in susceptible ... or patient ..., serum, or gastric fluid Infant disease is diagnosed on basis of the toxin being detected in ... or ... or a pos fecal culture

Food or patient feces, serum, or gastric fluid Feces or serum

Clostridium botulinum Ubiquitous in soil and water ... botulism is rare in US and usually involves improperly prepared or stored home-canned foods ... botulism is more common and is usually contracted by ingestion of contaminated food, dirt, or dust Colonization of GI tract follows

Foodborne Infant

C diff Primarily causative agent of antibiotic-associated ... infections ranging from self-limiting ... to ... ... which has high morbidity and mortality Resistant to certain antibiotics which alter the normal gut microbiome allowing for its endogenous growth or its exogenous acquisition from other sources

GI infections, diarrhea to pseudomembranous colitis

C tetani ... ... first leads to lockjaw due to contraction of facial muscles (.... ...) with drooling, sweating, and constant back spasms (....) ... ... results from infection of the umbilical stump which can become systemic with 90% mortality

Generalized tetanus, risus sardonicus, opisthotonos Neonatal tetanus

All species in both genera are gram ... w regard to their cell envelop ultrastructure and ... shaped w regard to cell morphology

Gram pos Rod-shaped bacilli

Clostridium botulinum Do not feed infants under 12 mo .... as it can contain endospores which are able to germinate in the immature GI tract in the absence of mature immune system

Honey

C tetani ... is an A-B subunit exotoxin, one of which is an endopeptidase that inactivates proteins that regulate release of inhibitory neurotransmitters ... ...-... acid and ... The result is unregulated excitatory synaptic activity in motor neurons, thereby conferring a state of ... paralysis

Tetanospasmin Gamma amino-butyric acid and glycine Spastic paralysis

Bacillus cereus Diarrheal form of food poisoning is an ... following ingestion of tainted food Incubation period is longer while reproduction occurs in GI tract w release of heat-labile enterotoxin

Infection

Fulminates in sepsis, resp failure, hypovolemic shock, and death within days of symptoms in absence of prompt therapy Hemorrhagic meningitis occurs in 50% of pts Pneumonia not typically seen

Inhalation anthrax—bacillus anthracis

Bacillus cereus Emetic disease is caused by an ... caused by ingestion of rice contaminated w heat-stable toxin Incubation period is then only hours and duration is about one day N/V, abdominal cramps Cooking kills vegetative cells, but spores survive Germination occurs in absence of refrigeration and the resulting toxin is not affected by reheating

Intoxication

Bacillus cereus Chemotherapy is not indicated as these are ... rather than infections

Intoxications

Inhalation anthrax ... toxin (protease) acts to stimulate macrophages to release pro-inflammatory lymphokines leading to tissue damage and shock, while the ... toxin (adenylate cyclase) causes edema

Lethal Edema

c tetani ... ... antitoxin protection assay if available in lab can cultivate the agent anaerobically

Murine tetanus

C diff Profuse abdominal cramping and diarrhea w fever White plaques form over intact tissue which are visible by colonscopy

Pseudomembranous colitis

Bacillus cereus Serious ... infections can occur when bacterium is introduced thru traumatic penetration of conjunctiva

Ocular infections

Inhalation anthrax Virulent strains possess the ... plasmid that carries genes for 3 protein toxin components which are only toxic in combination —protective antigen plus ... factor forms edema toxin —protective antigen plays ... factor forms lethal toxin

PXO1 plasmid Edema Lethal

Inhalation anthrax A second virulence factors involves the ... capsule It is coded for by 3 genes located on an additional plasmid designated ..., protects from phagocytosis

Poly-Dglutamic acid capsule, pXO2

C botulinum Wound infections are diagnosed on basis of toxin being detected in ... or ... or a pos wound culture Bioassay confirmation employs a ... ... protection test

Serum or wound Murine antitoxin

All are also ... organisms, therefore are ubiquitous in water and air, so found on all exposed environmental surfaces ... necessitates autoclaving for sterilization and incineration for decontamination

Soil Endosporogenesis

C tetani ... ... is used to vaccinate using a repeating cycle of booster doses Treatment involves debridement of wound, penicillin, or metronidazole to remove viable bacteria, passive immunization w tetanus ... for unbound toxin and vaccination w tetanus ... (disease does not confer immunity) Symptoms are treated until ... ... is recovered

Tetanus toxoid Ig, toxoid Synaptic transmission

Clostridium botulinum ... botulism is rarely seen ... botulism is the route by which bioweapons are designed to infect The infectious ... route results in disease w a rapid onset and high mortality

Wound Inhalation Aerosol