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Bacteriology.pptx
- 1. BACTERIOLOGY DR. RINSA VAHEED GLOBALINSTITUTE OF PUBLIC HEALTH 16th March2022
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- 5. BACTERIAL TOXINS Alternormal metabolism of host cells Often responsible for significant symptoms of bacterial infections Very few toxins have been identified Exotoxins (secreted by the bacterium) Type III cytotoxins modulate intracellular target Other toxins work on the surface of host cells Pattern recognition system/ pore forming toxins / cytotoxins( binds T cell receptor)
- 6. STAPHYLOCOCCUS Gram positive,Grape-like clusters Medically important species Staphylococcus aureus…causes pyogenic infection Staphylococcus epidermidis…..skin commensal Staphylococcus saprophyticus…..opportunistic pathogen Epidemiological importance Hospital cross infection More than 50% of hospital nursing staff Spread: direct contact, fomites, other vehicles Antibiotic resistant strains
- 7. STAPHYLOCOCCUS Colonize innose, other mucus membrane and skin of 30-40% of humans/ Carriers Causes focal abscess: Skin(boils), lungs, bones, Kidney and heart General Feature: Secrete potent exotoxins Toxic Shock Syndrome ...TSST1 Tampon Use Staphylococcal scalded skin syndrome Looks like skin has scalded or burned Food poisoning Develop in 30minutes to 8 hrs after consuming;
- 8. Entering thebody Do not penetrate deep tissue, Unless there is cut or wound, Laceration, insect bite, surgery, skin disease Area of infection remain localized. (Boil) Most local infection : collection of pus (abscess), furuncle, carbuncle Spread to subcutaneous or sub mucosal tissue: Cellulitis Cell for controlling infection: Nutrophils Host defense mechanism against staphylococcus
- 9. VIRULENCE FACTORS 1. Adherence factors/ Adhesins- (MSCRAMMS) 1. The microbial surface component recognises adhesive matrix molecules 2. Release of exotoxins 1. TSST 2. Alpha hemolysin
- 10. STREPTOCOCCUS Gram positive,arranged in chains 2Groups Group A Wide range of clinical manifestations Group B Leading cause of neonatal sepsis and meningitis
- 11. STREPTOCOCCUS Distributed worldwide, foundin skin and mucous membrane..20%of school aged children; Community-acquired pneumonia Asymptomatic Spread: direct contact, respiratory droplets, person to person contact Common infection in school children.. Pharyngitis or Strep throat....acute rheumatic fever (serious infection) • Acute rheumatic fever(serious infection)… carditis...inflammation of heart (scarring of valves) • Autoimmune disease: between strep A and antigen Affect skin and soft tissue: Pyoderma • Requires break in skin for bacteria to enter Infection mostly remain localized, some can invade deeper tissue, causing life-threatening infections
- 12. VIRULENCE FACTOR • Adhesin:Protein F (fibronectin-binding protein) • Protein G • Exotoxins: Erythrogenic toxins, Exotoxin A, Haemolysin
- 13. CORYNEBACTERIUM The mostimportant member of the genus is Corynebacterium diphtheriae A triple vaccine (DPT) is used for active immunization: The vaccine contains diphtheria toxoid, tetanus toxoid and pertussis vaccine. Pathogenicity: due to the production of a very powerful exotoxin. Immunocompromised individuals. Commensal corynebacteria are normally present in the throat, skin, conjunctiva and other areas.
- 16. PNEUMOCOCCUS Also calledStreptococcus pneumoniae Gram positive, Its cocci in pair Most common cause of bacterial pneumonia acquired in community Million death every year, throughout globe Infections Pneumonia, Bacteremia, Meningitis (in severe case) Spread: Person to person by respiratory droplets Initial colonization in nasopharynx and spread to lungs
- 18. VIRULENCE FACTOR Undergoclassic struggle with phagocytes Thick capsule: enables resistance Host produce : C reactive protein binds and activate complement TREATMENT Revolutionized by Penicillin Resistance developed... harder to treat Vaccines
- 19. CLOSTRIDIUM Large grampositive anaerobic bacilli Causes Tetanus... Cl tetani Botulism.... Cl botulinum Antibiotic associated diarrhea... Cl difficile Gas gangrene (myonecrosis involving muscle) …..Cl perfringens; Cl sporogenes ; Cl histolyticum Depending on exotoxins they secret A-G variety of serotype Only A, B, E affects humans
- 20. CLOSTRIDIUM Cl tetani Pathogenesis: Tetanus toxin.... Spasticity of muscles Cl botulinum Pathogenesis: Botulinum toxin (Neurotoxin).... Flaccid paralysis Food born; Wound botulism, Infant botulism, Iatrogenic Cl perfringens Pathogenesis: Alpha toxins which destroys phospholipids...gas production Compromised blood supply....Myonecrosis
- 21. VIRULENCE FACTOR OFCL BOTULINUM All Neurotoxins (except C2) enters blood stream Neuromuscular junction Binds on neuron terminates Prevent the release of acetyl choline Inhibition of muscular contraction Flaccid paralysis
- 22. MYCOBACTERIUM Acid fastbacilli Stained using Ziehl-Neelsen Three main groups Mycobacterium tuberculosis Tuberculosis Mycobacterium leprae Leprosy Non tuberculosis mycobacteria (NTM) Pulmonary disease
- 23. MYCOBACTERIUM TUBERCULOSIS Obligateaerobic bacilli....prefer oxygen Tuberculosis: World's most infectious killer Every year 10 million people fell ill Founder of bacteriology: Robert Koch Tubercle Bacillus, 24th March 1882 Primary infection...lower lobes of lungs Reactivated infection.... upper lobes of lungs Spread: droplet spread Infects macrophages
- 24. MYCOBACTERIUM LEPRAE Discoveredby Hansen, 1873 Causes Leprosy or Hansen disease Affects : Superficial tissue of skin and peripheral nerve Incubation period 3-5 years Spread : direct contact, air droplets Symptoms: Numbness of feet (due to nerve damage) Thickness and discolouration of skin Loss of sensation of skin....( injury or loss of finger and toes)
- 26. Phagocytosis ofmycobacterium, Bacteria grows and multiplies inside the cell Kills macrophage Fill bacteria in the lungs CD 4 T cells gets activated …(few weeks later) Releases interferon gamma Interferon gamma+ CD4 T cells + Macrophages …. Type 4 Hypersensitive reaction Granuloma formation... Caseating necrosis... Ghon focus in the lungs...Ranke complex(multiple complex with calcification)' VIRULENCE FACTORS
- 27. NEISSERIA Gram negative,aerobic, non-motile, non-sporing diplococci (arranged in pairs) Pathogenic species if Neisseria N. meningitidis N. gonorrhoeae Commensal of nasopharynx Spread: direct contact, droplet spread,
- 28. TYPES OF NEISSERIA NeisseriaMeningitis Meningitis common in early childhood (3mnths- 5 years) • Hemorrhagic skin rash • Sever condition: Waterhouse-Friedrichson syndrome..(purpuric rash, shock, Neisseria gonorrhoeae Characterized by : • Acute urethritis or dysuria.. In male • Mucopurulent cervicitis, Vulvovaginitis... in female
- 29. VIRULENCE FACTORS Capsular polysaccharide...protectsphagocytosis Serogroups A,B,C,Y....accounts invasion of disease Lipopolysaccharide and endotoxins Endotoxin bind to CD4 cells of host molecule... release of inflammatory mediators Produce endothelial injury... causes shock and myocardial dysfunction IgA proteases... cleaves mucosal igA
- 30. HAEMOPHILUS Gram negative,oxidase positive, pleomorphic bacilli, requires special growth factors X and V H. influenza: most pathogenic... pneumonia and meningitis in children Spread: person to person, direct contact, droplet spread
- 31. CENTRAL NERVOUS SYSTEMINFECTION Pyogenic meningitis...in children less then 2 years Subdural effusion...common complication; characterized by seizures Epiglottitis...older children 2-7years Pneumonia in infants......pleural involvement VIRULENCE FACTOR Capsule polysaccharide Endotoxin... induce host inflammatory response Outer member proteins IgA 1 proteases... inactivate IgA1 in mucosal surface Pili and other adhesion proteins.... helps in colonization on epithelial surface
- 32. LEPTOSPIRA Comes underthe classification of spirochaetes Delicate, Helical rot like structure, motile with endo flagella Important species: Leptospira interrogans and Leptospira biflexa Spread : Zoonotic disease (from animal to human) Leptospirosis... sever form called Weil's disease Contaminated water containing urine of animals...(through cut or abrasions/ mucosa)
- 34. SALMONELLA Rod-shaped Gram-negativebacteria of the family Enterobacteriaceae. Salmonella Typhi Causes: Typhoid fever / Enteric fever Constipation... following indigestion; Rose spot rashes all over the body; Diarrhea Salmonella paratyphi Parathyphoid fever...(milder infection) Spread : Feco-oral route Salmonella Enteriditis Watery diarrhea Spread : Human to animal
- 36. VIRULENCE FACTORS Vi Capsule...survive phogocytosis Endotoxins... systematic manifestation of salmonellosis Fimbriae....mediates binding of bacteria to terminal part of small intestine Acid tolerance response (ATR) gene... produced from stomach acid and acid PH of phagosome Catalase and Superoxide dismutase... protect from intercellular killing in macrophage
- 37. VIBRIO Short, Curved,Cylindrical gram-negative bacteria Important species: Vibrio Cholerae John Snow: Father of epidemiology Conducted study on cholera outbreak in mid 1800's V. cholerae Spread : Contaminated food and water; Poor hygiene Watery stool,
- 38. RICKETTSIA Nonmotile, gram-negative,non-spore-forming, highly pleomorphic bacteria Caused by Obligate intracellular parasite Fleas, lice, ticks and mites Rickettsial pox Maculopapular rash No human to human transmission
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- 40. CHLAMYDIA Small oligateintrecellular parasite Gram negative Cell wall not not well charcterized Inner and outer membrane Important species C . Trachomatis Conjuctivities Pneumonia in infants Urogenital infections
- 41. VIRULENCE FACTOR Infects epithelialcells/ Macrophages Down regulation of class IMHC Lymphoid follicle formation Fibrosis Disease result from destruction of cells and host immune response
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- 45. KLEBSIELLA Gram positive Non Motile Lactose Fermenting Rod shaped Bacteria Facultative Anaerobes Act as opportunistic human pathogen
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- 47. ESCHERIS COLI E.colibacteria discovered by Escherichia . Detection of E.coli in water indicates pollution and contamination and these are main source of infection Produce infection in Humans and Animals Morphology : Gram -ve , straight rods appear in pairs, Clasiification of E.coli Enteropathogenic Enterotoxigenic Enteroinvasive Enterohemorrhagic Enteroaggressive It produces Exotoxins : Haemolysin , Enterotoxin These exotoxins are the main reason for diarrheas
- 48. MAIN INFECTION CAUSED BYE.COLI Pyogenic Infection Intraabdominal Infection Peritonitis Abcess Speticimia Produce Drug resistance infection Neonatal meningitis Gastroenteritis
- 49. VIRULENECE FACTOR Surface AntigenToxin O Endotoxic Activity K protects against phagocytosis Fimbria which promote virulence
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- 52. SHIGELLA An Enterobacteriaceae Gram negative bacilli Mostly non-motile and Non- sporing They are aerobic sometimes facultative anaerobic Incubation period is about 12- 48 hours may vary between 1- 7 days
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- 54. PSEUDOMONAS A largegroup of aerobic ,non sporing gram negative bacteria Found natural water soil moist environment Opportunistic Pathogen
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- 56. ENTEROBACTERIA Aerobic andfacultative anaerobic Gram negative enteric bacilli. The most common members are Escherichia, Salmonella, Shigella, Klebsiella, Escherichia coli forms a part of normal intestinal flora of man and animal. There are four major types of clinical syndromes which are caused by Escherichia coli: 1. Urinary tract infection 2. Diarrhoea 3. Pyogenic infections 4. Septicaemia
- 57. BACILLUS Members ofthe genus Bacillus are ubiquitous, present in soil, dust, air and water and are frequently isolated as contaminants in bacteriological culture media. They are sporogenous, rod shaped, aerobic, Gram positive bacteria. Bacillus anthracis, the causative agent of anthrax, is the most important pathogen of the group. Bacillus cereus can cause food poisoning usually associated with fried rice from Chinese restaurants. It produces enterotoxin. The diseases is mild and self-limiting, requiring no specific treatment.
- 58. ACTINOMYCETES Actinomycetes areGram positive, filamentous bacteria intermediate in properties between true bacteria and fungi. The family Actinomycetes contains three major medically important genera, Actinomyces, Nocardia and Actinomadura. The Actinomyces causes a disease known as actinomycosis. The disease occurs in four clinical forms: cervicofacial, thoracic, abdominal and pelvic actinomyces.
- 59. YERSINIA Yersiniae areGram negative, short bacilli showing bipolar staining (safety pin appearance) with methylene blue. They are primary pathogens of rodents and men are accidentally infected. The genus yersinia contains three medically important species 1. Yersenia pestis - the caustive agent of plague 2. Yersinia pseudotuberculosis - a primary pathogen of rodents 3. Yersinia entercolitica - causes human diarrhoeal diseases In human, plague occurs in three forms: bubonic, pneumonic and septicaemic.
- 60. MYCOPLASMA Mycoplasmas differfrom other bacteria in that they lack a rigid cell wall. Due to lack of rigid cell wall, they are extremely plemorphic. They are resistant to cell wall antibiotics such as penicillins and cephalosporins. This again due to absence of cell wall. Mycoplasma causes two types of diseases in man – pneumonia and genital infections. Mycoplasma pneumoniae causes primary atypical pneumonia. Mycoplasma hominis causes non-gonococcal urethritis (NGU).
- 61. LEGIONELLA Legionella pneumophilais the most important species of the genus Legionella. The natural habitat of L. pneumophila is water. The organisms have been isolated from cooling towers, air conditioning systems, showers and respiratory ventilators. These sources facilitate transmission of the organism to the human respiratory tract by generating infectious aerosols. Legionella infection may occur in two main forms- Legionnaire's disease and Pontaic fever, together known as legionellosis.
- 62. BORDETELLA Three importantspecies of Bordetella include Bordetella pertussis, Bordetella parapertussis and Bordetella bronchiseptica. Bordetella pertussis is the main causative agent of whooping cough. Pertussis toxin is exotoxin produced by B. pertussis. Pertussis vaccine is generally administered in combination with diphtheria toxoid and tetanus toxoid (DPT). B. pertussis acts as an adjuvant for the toxoids producing better antibody response. Vaccine is very effective for prophylaxis.
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Editor's Notes
- #2 Before we start discussing Bacteriology it is important to discuss human microbiomes. All of the microbiomes that live IN and ON us!. So the Human body is only 25% human cells so when you look at me you are actually seeing 75% are bacteria, fungi and archery… Is int it amazing?. So whenever our body is exposed to the outside world, the mouth, the lungs, the GI tract, the skin, etc is exposed to the microbiome community. Even when a fetus is in its mother’s womb… it encounters microbiomes through the nutrients and blood supply through the mother. So at the time of birth when the baby passes through the birth canal during normal delivery, it encounters microbiomes in the canal.
- #6 A different class of toxins recognized are Exotoxins have separate A and B subunits/ components; typically they are secreted by the bacterium and what they do is bind with the R or receptor in the eukaryotic cell. it is taken inside the cell and there the A component is released inside the host cell to the cytoplasm and it causes its effect on the cell. Another type of toxin is called Type3 Cytotoxins… they look like a syringe injecting molecules into the cell's cytoplasm. This reaches the host cell by the structure of bacterium called secretory injection system.
- #7 Pyogenic infection in which pus is produced
- #10 Adherence factors: (the microbial surface component recognizing adhesive matrix molecules) These molecules recognize the most prominent components of the blood plasma, which include fibrinogen, fibronectin-binding proteins, collagens, etc Exotoxins: Toxic Shock syndrome toxins, alpha toxins alpha-hemolysin ( this alpha protein are the reason for the pore formation in staphylococcus infection) and Exfoliative Toxins Then the organism multiplies inside the host
- #13 Protein F (fibronectin-binding protein) -acts as a major adhesin to bind to pharyngeal epithelial cells. Protein G prevents the effective phagocytosis by binding with IgG through the Fc region Exotoxins: Erythrogenic toxins, Exotoxin A Hemolysin
- #14 Diphteriods are commensals of skin and mucous membrane
- #16 Diphtheria toxin consists of 1 molecule of A and 1 molecule of B. here B is the receptor-binding component. It binds with the HB-EGF receptors Through the binding, It enters the host cells through endocytosis The environment inside the host cell favours the B subunit to release into the cytoplasm And the A subunit will inhibit protein synthesis, as a result, the the DT affected cells will die
- #17 Also called Streptococcus pneumoniae Its Gram-positive, looks like Its cocci in pair Most common cause of bacterial pneumonia acquired in the community Million death every year, throughout globe infection……… it was reported about 1.6 million deaths annually in the pre-vaccination era Pneumococcus is still one of the most common causes of vaccine-preventable death worldwide with approximately 400,000 deaths in children aged less than 5 years, and around 1,500,000 deaths in all age groups in 2015 38 Pneumonia, Bacteremia, Meningitis (in severe case) Spread: Person to person by respiratory droplets Initial colonization in nasopharynx and spread to lungs
- #18 Invasive Pneumococcal disease is serious and causes serious threat to health Groups at high risk include elderly persons, person with chronic diseases and immunocompromised patient