Gram (+) cocci กลุม Catalase-positive (2H202 -> 2H2o + O2 <Gas> )
Lec3 - Staphylococci Genus: Staphylococcus
Grape-like cluster, Non-fastidious, Facultative anaerobe, Skin Normal flora
• Coagulase-positive
1. Staphylococcus aureus *
-
Pathogenic
Normal flora: skin
💊 Novobiocin susceptible
Highlight Lab:
- Coagulase positive
- Protein A
- Ferments mannitol
- MRSA: world-wide problem
- β- hemolysin -> ใชเปน control
CAMP test: แยก GAS, GBS
• Virulence factors
•
1. Protein A: จับกับ Fc IgG ปองกัน Antiphagocytic effect
2. Fibronectin-binding protein: จับกับ Fibronectin ของ cell
3. Cytolytic exotoxin: Membrane-damaging toxin
4. Enzyme: Coagulase ➟ fibrin formation
I) Free coagulase: จับ prothrombin
II) Bound coagulase (Clumping factor): ยึดตัวมันกับ fibrin
5. Superantigen exotoxin: CTK ↑ ↑
6. Exfoliatin ➟ Scalded skin syndrome
7. TSST-1: toxic shock syndrome toxin = Superantigen
•
Treatment:
- 💊 Drug of choice(IV): Cloxacillin?, Vancomycin(MRSA)
- Oral therapy: trimethoprim-sulfamethoxaxole
- Empirical therapy (ครอบคลุม ): MRSA strains
•
Disease (Not invasive)
➟ Stapylococcal Toxic Shock Syndrome(STSS)
8. Enterotoxins ➟ Scalded skin syndrome
** 15 enterotoxins(A-E, D-P) ≈ TSST-1 = Superantigen
•
Epidermiology: ผูหญิงมีรอบเดือน
- Skin& Mucosal surface
- Survive on dry surface
- Person to person spread: Contact, Exposure
- Risk factors: foreign body, surgical procedure
Use of antibiotics
** Infants, Young children w/ Poor hygiene, Shunts,
Viral respi infect, Compromise pulmonary function
Antibiotic resistance:
Penicillin resistance: β-Lactamase, Plasmid
Methicillin resistance: SCCmec area, mecA (สราง low aff PBP2a)
➟ PBP2a low affinity for all β-Lactam(ยา)
Vancomycin resistance: vanA สราง D-ala -D-lac dipeptide
➟ reduce vancomycin affinity
➟ Toxin-mediated disease: food-poisoning, TSS, Scalded skin
➟ Pyogenic diseases: imedigo แผลพุพอง, Folliculitis รูขุมขนอักเสบ,
Furuncle ฝหนอง, Carbuncles ฝฝกบัว
➟ Systemic disease *Un common except Shunt: เจาะคอ
•
Diagnosis
- Microscopy
- Cell culture: Non selective media(Plain agar)
• Coagulase-negative: มี Slime layer = virulence factor: จับ+ปองกัน
➳ Identification:
2. Staphylococcus epidermidis
Novobiocin resistance
Coagulase
Manitol fermentation
- Non pathogenic = No virulent
factors
- Normal flora: nose& skin
- Opportunistic infection
- Poly saccharide slime
- implanted Medical device
- Confirmed: Drawing blood 2 side !
- 💊 Novobiocin susceptible
3. Staphylococcus saprophyticus
- pathogenic: UTI in 95% female
•
Disease: Sub-acute endocarditis, Infection
nd
( 2 จาก E.coli)
- Normal human flora: skin,
mucosal
- Virulence factor = urease,
adhesin
- Most infections= Patient own
organism
- 💊 Novobiocin resistance !!!!!
• Treatment:
💊 Drug of choice(IV): oxacillin, Vancomycin(oxacillinresistance)
รักษาทันที: Endocarditis, Shut infection
Toxic Shock Syndrome(STSS): Stap vs Strep
Strep: Invasive -> Meningitis, Pharyngitis, Wound infection
Gram (+) cocci กลุม Catalase-negative (2H202 --X--> 2H2o + O2 <Gas>)
Lec4: Streptococci & Enterococci
In chain transparent colony, Fastidious, Facultative anaerobes, Hemolysis on BA, Skin Normal flora
• β- hemolytic (complete)
แบงตาม Lanfield group (A-G)
1. GAS: Streptococcus pyogenes
- 💊 Bacitracin sensitive
- Normal flora: skin oropharynx
- CAMP test negative (---- w/ S.aureus)
- Optochin bile resistance
• Virulence factors:
1. Streptococcal pyrogenic exotoxins
(Spe. A B C F): Some= super AG -> TSS
2. Streptolysins: pore forming toxin
3. M protein: cross reactive Ig, ยอย C3B
4. Streptokinase
5. Capsule (Hyaluronic acid)
• Diseases: sup/non-suppurative
1. Suppurative streptococcal disease
➟ Pharyngitis (strep/sore throat), Scarlet fever ไขอีดําอีแดง
➟ Skin infection: cellulitis, impetigo แผลพุพอง, Erysipelas ไฟลามทุง
➟ Necrotizing fasciitis (Flesh-eating disease/ Gangrene) 99%fetal
➟ STSS.
➟ Pneumonia, Meningitis.
➟ Septicaemia
+3,4. GCS, GGS: Streptococcus disgalatiae
: skin infection, tonsillitis, sepsis
+ 5. GDS
2. GBS: Streptococcus agalatiae
- Maternal intrapartum
- Normal flora: Urogenital GI URT
- CAMP test positive (--> w/ S.aureus)
- Bacitracin resistance
- Optochin bile resistance
•
Virulence factors: β hemolysin, capsule
• Diseases:
1. Neonatal disease: Bacteremia, Sepsis.
Pneumonia, Meningitis
2. Infect pregnant woman +postpartum
: UTI
3. Adult/Old age: Skin & Soft skin
infection
2. Non-suppurative streptococcal disease (2wk throat/ Scarlet
fever/ impetigo)
➟ Rheumatic fever & heart disease (Rheumatogenic strain)
- เกิดจาก Cross react Anti-M protein, Persistent Ig
-
Polyarthritis, Sydenham”s Chorea(Vitus dance), Nodules, Skin rash,
➟ Acute poststreptococcal glomerulonephritis (Nephritogenic strain)
- เกิดจาก Cross react with glomeruli
• α- hemolytic (partial)
•
Virulence factors: Pneumolysin: pore
forming toxin , Capsule, IgA protease
•
Diseases
➟ Purulent otitis media
3. Streptococcus pneumoniae
(Pneumococcus)
- gram (+) diplococci (pair lancet shape)
- mucoid colony
- Pathogenic @Nasopharynx
- Bacitracin resistance
- 💊 Optochin bile sensitive, bile
Soluble
• Viridans Group (heterogenous α, γ,
rare β hemolysis)
- Bacitracin resistance
- Optochin bile resistance
5.1 group viridian Strep (50% of case)
➟ Subacute bacterial endocarditis **
5.2 subgroup Mutans ➟ Dental caries
- mouth
5.3 subgroup Anginosus ➟ Wound
infection
- upR/GI/GU/Skin
Vaccine: Pneumonia conjugated vaccine
•
Antibiotic resistance: Penicillin, Amoxicillin, 3CG (ceftriaxone)
•
Disease: Meningitis +/- Hear lost
Sepsis. STSS
2nd รอง H. influenzae
➟ Sinusitis: 2nd รอง H. influenzae
➟ Lobar Pneumonia: common เด็ก<2y,
คนแก + Bronchopneumonia (Very uncommon)
➟ Meningitis: common ผูใหญ
4. Streptococcus suis
- tonsil and URT of pig
•
•
Virulence factors: Suilysin: pore
forming toxin, capsule
• Enterococcus: (α, γ, β)
➳ Enterococcus vs GDS:
- GPC in pair, short chain
- intestine
- Optochin bile & 6.5% NaCl resistance
- virulence factors: biofilm, hemolysin
6.1 Enterocoocus faecalis
• Disease: UTI, Peritonitis, Carditis
, Meningitis
6.2 Enterocoocus faecium
• VRE: Vancomycin Resistance
Enterococci (พบมาก) -> D-ala D-lac
➳ Sensitive test (Bacitracin & Optochin) :
Gram (+) Bacilli กลุม Aerobe & Facultative anaerobes ✅ O2
Lec6: Aerobic Gram-positive bacilli
•
กลุม Bacillus: Endospore/ Aerobes: Spore forming, Heat resistance, large,
Motile except B. antracis
1. Bacillus antracis
- non-motile
- capsule: poly-D-glutamic acid สรางจาก
Plasmid gene
- Central oval shape spore
- Non-fastidious: BA (non hemolytic),
Nutrient agar
- Human infection: จับ กิน สูด
2. Bacillus cereus
- motile
- Hemolysis on BA
- toxin-mediated food poisoning
(2 form: pre= heat & acid stable,
Secrete= heat labile)
**Resistance to penicillin & cephalosporins
• Virulence factors:
1. Capsule: g-D-glutamic acid
2. Complex protein toxins: heat-labile exotoxin
- PA: Protective antigen: จับ Receptor ตัด,
เปนทางเขาของ toxin (Heptamer)
- LF: Lethal factor: zinc-dependent
protease, cleaves ↓ MAPK -> death
- EF: Edema factor: calmodulin-dependent
adenylate cyclase, ↑cAMP -> Edema
• Clinical manifestations (2 form):
1. Emetic form: Heat stable ≈ Stap toxin
- incubation period < 6hr
- fired rice
- severe vomiting
•
treatment: Self-limiting=rehydration
• Clinical manifestations:
1. Cutaneous anthrax (20% mortality): Hide porter’s disease
ตุมนํ้ามีเลือด, blackened necrotic eschar, ไมไข&เจ็บ, ขยายตัว
2. Pulmonary anthrax (95% mortality): Hemorrhagic necrosis
3. GI anthrax (95% mortality): fever, toxemia, massive bloody
diarrhea
Diagnosis: Specimen - Aspiration
• n, swab, blood culture, Sputum
Lab - Gram stain, Culture ➟ Medusa head, Finger-like edge &
beaten egg whites, Dry ground glass surface
• Control & treatment:
💊 Drug of choice: Ciprofloxacin, penicillin
Vaccine: live attenuated spores (Stern vaccine: X plasmid)
Permanent live long Immunity
2. Diarrheal form: Heat labile ≈ Cholera toxin
- incubation period > 6hr
- Meat, veggie, pasta saurce
- severe vomiting
• กลุม Corynebacterium: Non-endospore/ regular shape: Palisade, Chinese
letter, Pleomorphic, stain unevenly, catalase + mycolic acid
3.1 Corynebacterium diphtheriae
•
Virulence factors:
•
Pathogenesis: Lecture pathology
• Disease:
1. Respiratory diphtheria: Incubate 2-5 days
Sudden onset: Bull neck, Sore throat, Darkgrey pesudomembrane
+ Complication: Respi obstruction, Myocarditis, Neuro sign
2. Cutaneous diphtheria:
Skin contact, Non-toxin-medaited, Necrosis ulcer
1. Diptheria toxin: lysogenic bacteriophage
2. Specific Corynephages: tox+ phages
- Club-shape
Tox <–> (Avirlulence) -> Tox + (Virulent)
- Skin Normal flora
- Methylene blue: Metachromatic granules
3. Exotoxin: ➟ local (Necrosis) & Systemic
(Volutin granules) สะสม polyphosphate: ATP
- fragment A: Inactivate Elongation factor-2
• Diagnosis:
- fastidious:
, inhibit protein synthesis
- Specimen: Throat swab, portion of Membrane
Enriched media=BA, Loeffler’s serum media - fragment B: bind membrane receptor
Selective media= K tellurite agar(grey->Black)
- Lab: Gram stain, Gold standard! : Elek test, PCR-tox gene
@heart, nerve cell
= CTBA (Cysteine Tellurite BA) -X->gram(-), NF
• Treatment & Control: Antitoxin, penicillin Contacts : toxoid
• Epidemiology: Age 2-5 yrs., Asymptomatic
vaccine (inactivated toxoid), erythromycin
carrier, Droplets, Incubate 2-5 days
DTP: คอตีบ ไอกรน บาดทะยัก ( DT, DTaP, DTwP, Tdap(3), Td(2))
3.2 Diphtheroid:
- gram positive/ palisade / Chinese letter
C.haemolyticum
Should know: Rhodococcus equi
- Facultative intracellular bac
- shape varies, Gram (+)
- Facultative intracellular organism
- Opportunistic pathogen
-
DT, DTaP, DTwP: เด็ก < 6 yrs.
Tdap(3), Td(2): ผูใหญ > 6 yrs.
•
-
Diagnosis:
Colorless to pale pink colonies
CAMP-test positive ≈GBS
Some = Acid-fast
•
Drugs: Antibiotic that penetrate intracellularly
-
Normal flora, cause disease in
immunocompromise: C.ulcerans,
Epidemiology: In forest, Dry & Dusty soil,
Animal, Wild animal, Bloodsucking insect
•
Disease: Common ➟ Pneumonia
•
Transmission: Inhalation, Inoculation,
Exposure to domestic animal
• กลุม Listeria & กลุม Erysipelothrix: Non-endospore/ irregular shape
: Listeriosis, gram (+) short rods, Tumbling movement กลิ้งที่ 20-25oc,
: CAMP-test positive
: Common food-borne: L. monocytogenes
4. Listeria monocytogenes
- Facultative intracellular bac
- food-borne pathogen
- primary reservoir = soil, water, ลําไสสัตว
- Facultative intracellular pathogen
- Transmission: Ingestion, Direct
contact
- grow in refrigeration * -> Trumpling
motility
+ Should know: Gardnerella vaginalis
- Gram-variable rod
- Gram (+) cell wall
5. Erysipelothrix rhusiopathiae
- Farm animal *Tonsil of PIG
- Small, slender, Gram (+) rod
- Microaerophilic, Partial/non hemolysis
• Virulence factors:
1. Hemolysin: Listeriolysin O -> lyse phagolytic
vacuole
2. ActA protein: สราง flagella จาก actin ->
Actin-based motility
3. Lipolytic soluble antigen: phospholipase C
enzyme (spreading) -> ทะลุผนัง2ชั้น (2 layers)
•
-
Disease: Listeriosis
Mild symptom: Flu-like
Septicemia & meningitis
Risk: คนทอง ทารก เด็ก คนแก
ภูมิตํ่า DM, ใชSteroid, โรคไต
•
-
Disease: Bacterial vaginosis
Association with Aerobes & Non-aerobes
Lactobacillus Dysbiosis
•
Occupational hazard: Erysipeloid (Finger
edema)
Risk: Fish handle, veterinarian, Gardener
•
Pathogenesis: IP-4 days, Erypesoid: นิ้วบวม
• Clinical manifestations:
1. Pregnancy- associated Listeriosis: Abortion, Still birth,
Transplacental spread, Intrauterine infection
2. Neonatal Listeriosis:
Early onset-> sepsis, respiratory distress, skin lesion
(Severe = Granulomatosis infantiseptica)
Late onset-> 2-3wks, meningitis
•
-
Diagnosis:
Meningitis: CSF-> low number of bacteria (Almost no organism)
CAMP test positive
Catalase positive
Culture: Cold enrichment process,
Liquid media -> Tumbling motility
Semi solid media -> Umbrella growth
•
Treatment & Control: 💊💊 Bivalent drug
•
-
Diagnosis:
White & grey vaginal discharge
Clue cells: เยือ้ ขาวหุม
Whiff test: 10%KOH, “Fishy odor 90%++”
-
💊 Drug of choice: Metronidazole, คู นอนไมตองรักษา
•
•
Identification:
Catalase negative, non-motile
Culture: BA -> pinpoint colony, alpha/non-hemolysis
Triple sugar iron (TSI) agar: H2S producer (Black Dark)
💊 Drug of choice: Penicillin, Clindamycin