3 SPOROGENOUS ANAEROBIC GRAM POSITIVE RODS * SPOROGENOUS ANAEROBIC GRAM POSITIVE RODS CLOSTRIDIA ● ● Generally large rods that are often club shaped due to presence of spore. ● ● Sporulation is variable ● ● All initially stain gram positive but may become gram negative rapidly.
4 Pathogenic Potential of Clostridium -1- ● ● Very proteolytic and aerogenic; elaborate multiple toxins. ● ● Common inhabitants of the gastrointestinal tract and the female genital tract.
5 Pathogenic Potential of Clostridium -2- Some members associated with specific diseases. ● I.Gas Gangrene C. perfringens (type A), C. septicum C novyi type A, C. bifermentans C. histolyticum, C. sordelli, C. sporogenes ● II.Tetanus ● II.Tetanus ‑ C. tetani ● III.Botulism ‑ C. botulinum
6 Pathogenic Potential of Clostridium -3- ● IV.Antibiotic-associated Diarrhea and Colitis and Colitis C. difficile; rare C. perfringens type C ● V.Miscellaneous infections - wounds, abscess, soft tissue infection, myonecrosis, bacteremia: C. perfringens, C. ramosum, C. septicum, C. sporogenes and others
7 Tetanus -1- C. tetaniThe spores of C. tetani are found in feces of humans and animals and in soil. Signs and symptoms * Signs and symptoms :Tetanus affects skeletal muscles. * Mortality rates vary from 40% to 78%.
8 Tetanus -2- ● Generalized tetanus ● Generalized tetanus is the most common type of tetanus, representing about 80% of cases. ● Neonatal tetanus ● Neonatal tetanus is a form of generalized tetanus that occurs in newborns.
9 Tetanus -3- Neonatal tetanus ● ● A frequent cause of death in developing countries ● ● Most common causes: cutting the umbilical cord with unsterilized instruments or infection of the umbilical stump ● ● The fatality rate: around 90% ● ● The common death cause: respiratory failure
10 Tetanus -4- ● Local tetanus Uncommon form of the disease ● Cephalic tetanus ● Cephalic tetanus is a rare form of the disease
11 Tetanus -5- (tetanospasmin) The tetanus toxin (tetanospasmin) travels to the central nervous system and binds to nerve tissue. Prevents the inhibitory signals to the motor neurons and results in prolonged contraction of extensor and flexor muscles. C. tetanitetanolysin. C. tetani also produces tetanolysin.
12 Tetanus -6- ● tetanospasmin opisthotonos. ● Muscle spasms mediated by tetanospasmin produces a characteristic arching posture known as opisthotonos. ● ● Without treatment, the patient ultimately succumbs to respiratory failure. ● ● The incubation period ranges from 1 ‑ 54 days; generally 6 ‑ 15 days.
14 Tetanus -8- Diagnosis ● ● The diagnosis is based on clinical symptoms and patient history (i.e.lack of current vaccination). ● ● No attempt is made to cultivate the organism. ● ● A Gram stain of wound exudate (if available) may demonstrate Gram positive rods and gram negative rods with swollen ends due to the presence of spores.
15 Tetanus Tetanus -9- Latent period4-5d ～ several weeks Latent period: 4-5d ～ several weeks Lockjaw, sardonic smile opisthotonos
17 Tetanus -11- Therapy Treatment usually focuses on ● ● controlling muscle spasms, ● ● stopping toxin production and ● ● neutralizing the effects of the toxin.
18 Botulism Botulism -1- ●C. botulinum ● The causative agent, C. botulinum, is found in soil, freshwater, and seawater sediments. ●neuroparalytic disease ● Botulism is a neuroparalytic disease. ●C.botulinum ● The toxin of C.botulinum acts by blocking nerve function and leads to respiratory and musculoskeletal paralysis. ● acetylcholine ● The toxin affects nerves,it affect specifically, the inhibition of the release of acetylcholine from motor neurons.
19 Botulism Botulism -2- ● about one microgram is lethal to humans ● Botulism toxin is one of the most powerful known toxins: about one microgram is lethal to humans. ● ● In all cases illness is caused by the toxinC. Botulinum. toxin made by C. Botulinum.
21 Botulism Botulism -4- Mode of acquisition 1-Infant botulism. ● The most common form in Western countries, ● This occurs in small children who are colonised with the bacterium during the early stages of their life. ● The bacterium releases the toxin into the intestine, consumption of honey during the first year of life the consumption of honey during the first year of life has been identified as a risk factor for infant botulism.
22 Botulism -5- 2-Foodborn botulism. Results from contaminated Results from contaminated foodstuffs in which C. botulinum spores have been allowed to germinate and produce botulism toxin. 3-Wound botulism. Results Results from the contamination of a wound with the bacteria
23 Botulism -6- Diagnosis ● C.botulinum infections should be made on clinical grounds. ● Confirmation of the diagnosis is made by testing of a stool or enema specimen with the mouse.
25 Botulism -8- Treatment Botulism Immunoglobulin Intravenous Human * The only drug currently available to treat infant botulism is “Botulism Immunoglobulin Intravenous Human”. “horse-derived antitoxin”. * If diagnosed early, foodborne and wound botulism can be treated by inducing passive immunity with a “horse-derived antitoxin”.
26 Pseudomembranous colitis -1- C.difficile. ● Infection of the colon,often,but not always caused by the bacterium C.difficile. ● ● This disease is induced by long term use of broad spectrum antibiotics ● seudomembrane. ● It is characterized by the presence of colonic plaques that form a pseudomembrane.
27 Pseudomembranous colitis -2- C. difficile ● Key factor in the pathogenesis of PMC is a disturbance of the normal bowel flora that permits C. difficile to overgrow the endogenous flora, produce toxin and induce disease. ● Approximately 2% of healthy adults carry C. difficile C. difficile as commensal flora
28 Pseudomembranous colitis -3- Diagnosis ● Visualization of characteristic pseudomembranous plaques by colonoscopy ● Detection of the toxin is the most accurate diagnosis way but is difficult to perform. C. difficile ● C. difficile can be cultured on special media CCFA ‑ cycloserine, cefoxitin, egg yolk, fructose agar.
29 Pseudomembranous colitis -4- MAP :Mitojen Activated Protein Kinases
31 Pseudomembranous colitis -6- ● The disease is usually treated by oral metronidasole (500 mg every 8 hours) ● Oral vancomycin (125 mg every 6 hours) ● Additionally treatment by probiotics
32 Anaerobic cellulitis -1- proteolytic clostridia ● Invasion of necrotic wound tissue by the proteolytic clostridia. ● Characterized by gas accumulation, discoloration of the underlying skin, and the presence of a malodorous, brownish, purulent discharge.
34 Clostridial myonecrosis or gas gangrene -1- ● Gas gangrene is associated with severe deep wounds. Clostridial myonecrosisGas gangrene ● Clostridial myonecrosis or Gas gangrene develop in a lowered oxidation ‑ reduction potential present in the wound.
35 Clostridial myonecrosis or gas gangrene -2- This situation was caused by ● The presence of foreign bodies in the wound, ● Failure of the blood supply to the infected area, ● The presence of necrotic tissue and hemorrhagie in the wound, ● The presence and multiplication of other bacteria.
36 Clostridial myonecrosis or gas gangrene -3- ● Clinical features of gas gangrene include marked systemic toxicity, fever,tachycardia, and a tender, painful edematous wound with a sweet ‑ or foul ‑ smelling discharge. C. perfringensC. novyi and C. septicum, and Clostridium clostridiforme ● The most frequently encountered species are C. perfringens (predominant), C. novyi and C. septicum, and Clostridium clostridiforme.
38 C. perfringens food-borne illness -1- ● This is reported to be the third most common form of food poisoning in the world. ● The predisposing factor appears to be the ingestion of improperly cooked/stored meat or meat product. ● Most patients are afebrile.
39 C. perfringens food-borne illness -2- ● There is nausea and vomiting in one third of the cases; stools are usually foamy and foul smelling. ● The illness is usually mild and self-limiting. Diagnosis ● Diagnosis is confirmed by the recovery of a large number of organisms (>108 spores/g feces) from stool.
40 Isolation and Identification of Clostridia -1- ● Identification of the commonly encountered clostridia can often be accomplished on the basis of colony morphology, growth on selective media, aerotolerance determination and a few screening tests. Egg Yolk agar (EYA) ● Egg Yolk agar (EYA) is commonly employed for the identification of clostridia.
41 Isolation and Identification of Clostridia -2- lecithinase lipase ‑ ● EYA is useful for the detection of two enzymes: lecithinase ‑ precipitation around colony on EYA, lipase ‑ iridescent sheen at edge of colony on EYA. Alpha toxin C. perfringens ● Alpha toxin is a specific form of lecithinase produced by C. perfringens and a few other clinically important clostridia.
43 ASPOROGENOUS ANAEROBIC GRAM POSITIVE RODS as commensal flora ● Heterogeneous group of organisms that may be recovered as commensal flora on a variety of mucosal surfaces including the: upper respiratory tract, gastrointestinal tract, female genitourinary tract.
44 ASPOROGENOUS ANAEROBIC GRAM POSITIVE RODS -1- ● The genera observed vary with the anatomic site. These organisms are considered to be opportunistic pathogens that take advantage of breaks in the integrity of the mucosal surfaces. recovered from polymicrobic infections ● Usually recovered from polymicrobic infections involving facultative bacteria (enterics, staphylococci,streptococci) or anaerobic gram negative rods (Bacteroides or Fusobacterium).
45 ASPOROGENOUS ANAEROBIC GRAM POSITIVE RODS -2- The most commonly encountered genera are: ● Actinomyces, ● Bifidobacterium, ● Eubacterium, ● Propionibacterium, ● Mobiluncus, ● Lactobacillus
46 ACTINOMYCES Actinomyces are branching anaerobic or microaerophilic, non-sporulating Gram positive bacilli
47 ACTINOMYCOSIS -1- Actinomyces sp. ● Actinomycosis is an endogenous infection caused by Actinomyces sp. chronic suppurative disease ● The infection usually manifests as a chronic suppurative disease that may produce granulomatous lesions. ● The infection spreads by direct extension through contiguous tissue including connective tissue and bone.
50 BIFIDOBACTERIUM Pathogenicity Members of this genus are oral and intestinal commensal flora which are associated with polymicrobic infections, especially pulmonary. They are rarely encountered in clinical material. B. dentium B. dentium appears to be the only species with pathogenic potential.
51 BIFIDOBACTERIUM Characteristics ● Gram stain demonstrates irregular clusters of pleomorphic Gram positive rods to filamentous or branching filamentous forms. strict anaerobes ● Bifidobacteria are strict anaerobes
52 Bifidobacterium strains are important probiotics Different species and/or strains of Bifidobacteria may exert a range of beneficial health effects, including ● The regulation of intestinal microbial homeostasis ● The inhibition of pathogens and harmful bacteria that colonize and/or infect the gut mucosa
53 Bifidobacterium strains are important probiotics ● The modulation of local and systemic immune responses ● The repression of procarcinogenic enzymatic activities within the microbiota ● The production of vitamins, and the bioconversion of a number of dietary compounds into bioactive molecules
54 PROBIOTICS According to the currently adopted definition by FAO/WHO, probiotics are: "Live microorganisms which when administered in adequate amounts confer a health benefit on the host.According to the currently adopted definition by FAO/WHO, probiotics are: "Live microorganisms which when administered in adequate amounts confer a health benefit on the host.FAOWHOFAOWHO Lactic acid bacteria (LAB) and bifidobacteria are the most common types of microbes used as probioticsLactic acid bacteria (LAB) and bifidobacteria are the most common types of microbes used as probioticsLactic acid bacteria bifidobacteria microbesLactic acid bacteria bifidobacteria microbes
56 EUBACTERIUM. 1. Pathogenicity ● Members of the genus, primarily E. lentum E. lentum are rarely encountered in the clinical setting.It is transfered to the genus Eggerthella lenta Eggerthella and called Eggerthella lenta ● Most isolates are recovered from opportunistic, polymicrobic infections. ● Recent studies indicate that some members of the genus may be associated with periodontal infections
57 PROPIONIBACTERIUM PathogenicityPathogenicity: *Commensal flora ofr the skin, found on mucosal surfaces of the upper respiratory, gastrointestinal and urogenital tract. *Contaminant in specimens collected percutaneously. PropionibacteriaPropionibacteria have been recovered from infections involving prosthetic heart valves and joints as well as ventricular shunts.
58 PROPIONIBACTERIUM ● Sequelae have included osteomyelitis, septicemia, endocarditis and meningitis. ● P. acnes plays a role in the development of acne. ● P.propionicus, which closely resembles A.israelii, has been isolated also from cases of actinomycosis.
60 LACTOBACILLUS Pathogenicity ● Pathogenicity: Lactobacilli are the predominant commensal flora of the UGT in postpubescent females; they are also commensal flora of the oral cavity and intestinal tract. endocarditis, neonatal meningitis, chorioamnionitis as well as bacteremia and pulmonary infections ● Members are rarely associated with infections. However, lactobacilli have been recovered from cases of endocarditis, neonatal meningitis, chorioamnionitis as well as bacteremia and pulmonary infections.
61 LACTOBACILLUS Characteristics Characteristics: ● Most members are aerotolerant, producing larger colonies when grown anaerobically. Lactobacillusstrains are important probiotics ● Lactobacillus strains are important probiotics ● Lactobacilli ferment carbohydrates mainly to lactic acid.
62 MOBILUNCUS Pathogenicity ● Members of the genus are commensal flora for the genital tract and terminal portion of the gastrointestinal tract (rectum). bacterial vaginosis ● These organisms have been isolated from 50-65% of women diagnosed with bacterial vaginosis as well as the sex partners of these women. Gardnerella vaginalis clue cells ● The organisms have the ability to attach to vaginal epithelial cells in conjunction with Gardnerella vaginalis to form "clue cells". Mobiluncus species have been recovered from women with Pelvic Inflammatory Diseases.
63 MOBILUNCUS Characteristics Characteristics: ● Members of the genus are the only asporogenous anaerobic gram positive rod, clinically encountered, that are usually motile. ● Cells are gram positive to gram variable and may be curved.
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