Medical Bacteriology Course Outline (MBMM OmpathStudy

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