Explore the Bacteriology course outline for Year 2 Microbiology. Master bacterial identification, physiology, and pathogenesis.
DEPARTMENT OF MEDICAL MICROBIOLOGY MBMM3311 MEDICAL BACTERIOLOGY Pre-requisite: Principles of Microbiology Course Purpose: To equip the student with knowledge and skills on bacteriology EXPECTED LEARNING OUTCOMES By the end of the course unit, the student should be able to: - Classify bacteria, Chlamydia, Rickettsiae and Mycoplasma - Describe pathogenesis of bacteria, Chlamydia, Rickettsiae and Mycoplasma - Identify micro-organisms using laboratory methods COURSE OUTLINE GRAM POSITIVE BACTERIA WEEK 1: GRAM POSITIVE COCCI Staphylococcus Species: - Staphylococcus aureus - Causes skin infections, pneumonia, septicemia, toxic shock syndrome, food poisoning - Staphylococcus epidermidis - Causes opportunistic infections, catheter-related infections - Staphylococcus saprophyticus - Causes urinary tract infections, especially in young women Streptococcus Species: - Streptococcus pyogenes (Group A Streptococcus) - Causes pharyngitis, scarlet fever, rheumatic fever, necrotizing fasciitis - Streptococcus agalactiae (Group B Streptococcus) - Causes neonatal meningitis and sepsis - Streptococcus pneumoniae - Causes pneumonia, meningitis, otitis media, sinusitis - Enterococcus species (Group D) - Causes urinary tract infections, endocarditis, wound infections PRACTICAL SESSION: Identification of Microorganisms Culture Characteristics: - Colony morphology on Blood agar and Mannitol salt agar - Haemolytic reactions: Alpha hemolysis (partial/green), Beta hemolysis (complete/clear), Gamma hemolysis (no hemolysis) Biochemical Characteristics: - Coagulase test - Differentiates S. aureus (positive) from other staphylococci (negative) - Catalase test - Differentiates staphylococci (positive) from streptococci (negative) - Bacitracin sensitivity - Identifies Group A Streptococcus (sensitive) - Optochin sensitivity - Identifies S. pneumoniae (sensitive) - Bile solubility test - Confirms S. pneumoniae (positive) Staining Techniques: - Gram staining procedure and interpretation - Acid-fast staining technique --- WEEK 2: GRAM POSITIVE SPORE-FORMING RODS Bacillus Species (Aerobic): - Bacillus anthracis - Causes anthrax (cutaneous, pulmonary "woolsorter's disease", gastrointestinal forms) - Bacillus cereus - Causes food poisoning with two syndromes: emetic (rice) and diarrheal Clostridium Species (Anaerobic): - Clostridium tetani - Causes tetanus (lockjaw) through neurotoxin production - Clostridium botulinum - Causes botulism (flaccid paralysis) through neurotoxin in contaminated food - Clostridium perfringens - Causes gas gangrene, food poisoning, necrotizing enteritis - Clostridium difficile - Causes pseudomembranous colitis and antibiotic-associated diarrhea WEEK 3: GRAM POSITIVE NON-SPORE FORMING RODS - Corynebacterium diphtheriae - Causes diphtheria with pseudomembrane formation in throat, produces diphtheria toxin - Listeria monocytogenes - Causes meningitis, septicemia in neonates and immunocompromised patients, causes spontaneous abortion in pregnant women GRAM NEGATIVE BACTERIA WEEK 2: GRAM NEGATIVE COCCI Neisseria Species: - Neisseria gonorrhoeae - Causes gonorrhea (sexually transmitted infection), urethritis, cervicitis, pelvic inflammatory disease, neonatal conjunctivitis - Neisseria meningitidis - Causes meningococcal meningitis and meningococcemia (severe septicemia with petechial rash) WEEK 4: GRAM NEGATIVE RODS - ENTEROBACTERIACEAE Major Enteric Pathogens: - Escherichia coli - Causes urinary tract infections, gastroenteritis (ETEC, EPEC, EHEC, EIEC), neonatal meningitis, septicemia, travelers' diarrhea - Salmonella typhi - Causes typhoid fever (enteric fever) with sustained fever, rose spots, and intestinal perforation - Salmonella enteritidis and other non-typhoidal Salmonella - Cause gastroenteritis and food poisoning --- WEEK 5: GRAM NEGATIVE RODS - ENTERIC PATHOGENS Intestinal Pathogens: - Shigella species (dysenteriae, flexneri, boydii, sonnei) - Cause bacillary dysentery with bloody diarrhea, abdominal cramps, tenesmus - Vibrio cholerae - Causes cholera with severe watery diarrhea ("rice water stools"), leading to dehydration - Vibrio parahaemolyticus - Causes gastroenteritis from contaminated seafood - Campylobacter jejuni - Causes gastroenteritis with bloody diarrhea, associated with Guillain-Barré syndrome - Helicobacter pylori - Causes peptic ulcer disease, chronic gastritis, gastric carcinoma, MALT lymphoma --- WEEK 6: GRAM NEGATIVE RODS - OPPORTUNISTIC PATHOGENS Hospital-Acquired and Opportunistic Infections: - Klebsiella pneumoniae - Causes pneumonia (especially in alcoholics), urinary tract infections, septicemia, produces thick mucoid colonies - Proteus mirabilis - Causes urinary tract infections with ammonia smell, produces urease, kidney stones, wound infections - Pseudomonas aeruginosa - Causes nosocomial infections, burn wound infections, pneumonia in cystic fibrosis patients, produces blue-green pigment (pyocyanin) - Bacteroides fragilis (Anaerobic) - Causes intra-abdominal infections, peritonitis, abscesses, anaerobic sepsis --- WEEK 7: GRAM NEGATIVE RODS - RESPIRATORY PATHOGENS Haemophilus Species: - Haemophilus influenzae - Causes meningitis, epiglottitis, pneumonia, otitis media, sinusitis (especially in children) - Haemophilus ducreyi - Causes chancroid (painful genital ulcer), a sexually transmitted infection Other Respiratory Pathogens: - Legionella pneumophila - Causes Legionnaires' disease (severe atypical pneumonia) and Pontiac fever, spreads through water systems - Bordetella pertussis - Causes whooping cough (pertussis) with paroxysmal cough and inspiratory whoop --- WEEK 8: GRAM NEGATIVE RODS - ZOONOTIC ORGANISMS (Animal-Related) Brucella Species: - Brucella melitensis - From goats and sheep - Brucella abortus - From cattle - Brucella suis - From pigs All cause brucellosis (undulant fever) with fever, sweating, arthralgia, hepatosplenomegaly Other Zoonotic Bacteria: - Yersinia pestis - Causes plague in three forms: bubonic (enlarged lymph nodes/buboes), pneumonic (severe pneumonia), and septicemic - Pasteurella multocida - Causes cellulitis and wound infections from animal bites (cats and dogs) - Francisella tularensis - Causes tularemia (rabbit fever) with ulceroglandular syndrome --- SPECIAL BACTERIA AND RELATED ORGANISMS --- WEEK 9: MYCOBACTERIA (ACID-FAST BACTERIA) Mycobacterium Species: - Mycobacterium tuberculosis - Causes tuberculosis (pulmonary TB and extrapulmonary TB affecting bones, kidneys, brain) - Mycobacterium leprae - Causes leprosy (Hansen's disease) with two forms: lepromatous and tuberculoid Atypical Mycobacteria (Non-tuberculous Mycobacteria): - Mycobacterium avium complex (MAC) - Causes opportunistic infections in AIDS patients, pulmonary disease - Mycobacterium kansasii - Causes pulmonary disease similar to TB - Mycobacterium marinum - Causes skin infections (swimming pool granuloma, fish tank granuloma) - Mycobacterium ulcerans - Causes Buruli ulcer with necrotizing skin lesions Note: Mycobacteria are characterized by their acid-fast property due to mycolic acid in their cell walls --- WEEK 10: ACTINOMYCETES AND MYCOPLASMAS Actinomycetes (Filamentous Bacteria): - Actinomyces israelii - Causes actinomycosis with three forms: cervicofacial ("lumpy jaw"), thoracic, and abdominal, characterized by sulfur granules - Nocardia asteroides - Causes nocardiosis with pulmonary infections and disseminated disease, especially in immunocompromised patients Mycoplasmas (Cell Wall-Deficient Bacteria): - Mycoplasma pneumoniae - Causes atypical pneumonia (walking pneumonia), tracheobronchitis - Mycoplasma hominis - Causes pelvic inflammatory disease, postpartum fever - Ureaplasma urealyticum - Causes non-gonococcal urethritis, reproductive tract infections Note: Mycoplasmas are the smallest free-living organisms, resistant to beta-lactam antibiotics due to lack of cell wall --- WEEK 11: SPIROCHETES (SPIRAL-SHAPED BACTERIA) Treponema Species: - Treponema pallidum - Causes syphilis with three stages: primary (chancre), secon