Microbiology (Unit 9)

Promote Microbial Growth: Skin

• moist/sebum rich → certain areas more hospitable

• norm flora: Cultibacterium & Staphylococcus

Bacterial Skin Diseases: Pyodermic Infections

• pathogen: S. aureus

• s/s: pustules (raised pus skin lesions: folliculitis < furuncles < carbuncles)

• virluence: leukocidins → kill wbcs

• transmisson: direct/indirect

• detection: inspection/culture swabs (severe)

• entry: parenteral

• treatment: self limiting, ab for severe

Bacterial Skin Diseases: Scalded Skin Syndrome

• pathogen: S. aureus

• s/s: bulla (fluid filled lesion, >1cm), red/severe peeling

• virluence: exotoxin

• transmisson: direct/indirect

• detection: inspection/culture swabs (severe)

• entry: parenteral

• treatment: IV antibiotics

Bacterial Skin Diseases: Impetigo

• pathogen: S. aureus

• s/s: vesicles (fluid filled, <1cm), pustule/bulla rupture + form crusts

• transmisson: direct/indirect

• detection: inspection/culture swabs (severe)

• entry: parenteral

• treatment: topical antibiotics

Bacterial Skin Diseases: Necrotizing Fasciitis

• pathogen: S. pyogenes

• s/s: pain, swelling, bulla (foul smell), necrosis, ↓ bp

• virluence: capsule, m protein, exoenzymes (ex. proteases)

• transmisson: direct

• detection: inspection/culture swabs (severe)

• entry: parenteral

• treatment: debridement (remove infected), amputation, IV antibiotics

Bacterial Skin Diseases: Acne

• pathogen: C. acnes

• s/s: papules (sm raised lesions) + pustules

• virluence: bacterium consumes sebum in comedones (white/blackheades) → inflam

• transmisson: oppurtunistic

• detection: inspection/culture swabs (severe)

• entry: skin

• treatment: topical agents, antibiotics

Viral Skin Diseases: Herpes Simples Virus Type I

=cold sores

• pathogen: hsv

• s/s: painful vessicles on lips → burst + form crusts

• virluence: latent/recurrent, travels to trigeminal nerve + hiberante

• transmisson: direct (more during active infection)

• detection: inspection, lab testing (severe)

• entry: mucus mems

• treatment: antivirals

Viral Skin Diseases: Herpes Simples Virus Type II

=genital herpes

• pathogen: hsv

• s/s: painful vesicles on/around genitals → burst/form crust

• virluence factors: latent/recurrent, travels to lumbar-sacral nerves + hibernate

• transmisson: direct (more during active infection)

• detection: inspection, lab testing (severe)

• entry: mucus mems

• treatment: antivirals

Fungal Skin Diseases: Cutaneous Candidasis

• pathogen: C. albicans

• s/s: red, itchy rash on skin folds

• transmisson: oppurtunistic

• detection: inspection

• entry: skin

• treatment: anti-fungal

Fungal Skin Diseases: Vaginal Yeast Infection

• pathogen: C. albicans

• s/s: itching, thick yellow/white discharge, odor

• transmisson: oppurtunistic

• detection: inspection

• entry: skin

• treatment: anti-fungal

Fungal Skin Diseases: Thrush

• pathogen: C. albicans

• s/s: white patches in mouth, potential bleeding

• transmisson: oppurtunistic

• detection: inspection

• entry: skin

• treatment: anti-fungal

Promote Microbial Growth: Respiratory System

• can carry potential pathogenic organisms in upper resp (ex. S. heamophilus, Neisseria)

• none in lower resp (protected by: mucus, ciliary escalator, alveolar macrophages, IgA)

Bacterial Respiratory Diseases: S. pneumoniae

• disease: bacterial pneumonia

• s/s: painful breathing w fluid in alveoli

• virluence: capsule, autolysins (degrade cell wall/promote adherence)

• transmisson: direct (common)/indirect

• detection: gram pos

• entry: mucus mems (resp)

• treatment: antibiotics

• vaccine: conjugate

Bacterial Respiratory Diseases: H. influenzae

• disease: bacterial pneumonia

• s/s: painful breathing w fluid in alveoli

• virluence: capsule

• transmisson: direct (common)/indirect

• detection: gram neg

• entry: mucus mems (resp)

• treatment: antibiotics

• vaccine: conjugate

Bacterial Respiratory Diseases: M. pneumoniae

• disease: bacterial pneumonia

• s/s: painful breathing w fluid in alveoli

• virluence: more mild

• transmisson: direct (common)/indirect

• detection: no cell wall

• entry: mucus mems (resp)

• treatment: self limiting

• vaccine: no

Bacterial Respiratory Diseases: Strep Throat

• pathogen: S. pyogenes

• s/s: swollen tonsils/lymph nodes, petechiae (red bumps) on palate

• virluence factors: capsule, m protein, exoenzymes (ex. proteases)

• transmisson: direct (common)/indirect

• detection: culture swab

• entry: mucus mems

• treatment: antibiotics

• vaccine: none

Bacterial Respiratory Diseases: Tuberculosis

• pathogen: M. tuberculosis

• s/s: chronic cough, chest pain, cough blood

• virluence: mycolic acid protects against digestion after phago → rep inside macro forming tubercles → chronic inflam (more macro recruited) → tubercles rupture → blood/bacteria spreads

• transmisson: direct (common)/indirect

• detection: tuberculin skin test → X-ray (if pos)

• entry: mucus mems

• treatment: antibiotics

• vaccine: yes

Bacterial Respiratory Diseases: Pertussis (Whooping Cough)

• pathogen: B. pertussis

• s/s: mild → uncontrolable coughing w whoop (long recovery w chronic cough)

• virluence factors: adhesins, a-b exotoxin, cytotoxin (damages ciliated ep cells → ↑ mucus)

• transmisson: direct (common)/indirect

• detection: culture swab

• entry: mucus mems

• treatment: antibiotics

• vaccine: yes

Viral Respiratory Diseases: Common Cold

(viral resp milder than bacterial)

• pathogen: coronavirus

• s/s: runny nose, pharyngitis

• virluence: antigenic variation

• transmisson: direct (more)/indirect

• detection: symps, viral diagonisitc tests

• entry: mucus mems

• treatment: self limiting

• vaccine: none

Viral Respiratory Diseases: Influenza

• pathogen: influenza virus

• s/s: fever, chills, body ache

• virluence: antigenic variation

• transmisson: direct (more)/indirect

• detection: symps viral diagnostic tests

• entry: mucus mems

• treatment: self limiting, antivirals

• vaccine: yes

Viral Respiratory Diseases: Viral Pneumonia

• pathogen: influenza virus

• s/s: fever, cough (longer lasting than flu)

• virluence: antigenic variation

• transmisson: direct (more)/indirect

• detection: symps, viral diagnostic

• entry: mucus mems

• treatment: self limiting, antiviral

• vaccine: yes

Influenza Virus: Antigenic Variation

= depends on combo of spike proteins

• hemagglutinin (H): viral entry

• neuraminidase (N): viral exit

evolutionary changes:

• anitgenic drift: point mutations cause slight changes in spike proteins (new vaccines yearly)

• anitgenic shift: lrg changes due to gene reassortment → host infected w multiple influenza viruses (→ new influenza virus)

Viral Respiratory Diseases Leading to Skin Rashes: Chicken Pox

• pathogen: Varicella-zoster virus

• s/s: viremia (virus detectable in blood) & pustular rash on face → burst → crusts

• virluence: moves along sensory nerves to dorsal ganglia → becomes dormant

• transmisson: direct (more)/indirect

• detection: symps, diagnostic tests

• entry: mucus mems

• treatment: self limiting

• vaccine: yes

Viral Respiratory Diseases Leading to Skin Rashes: Shingles

• pathogen: Varicella-zoster virus

• s/s: virus reactivated (stress, aging, immunosuppression) → moves along sensory nerves → painful lessions (vesicles/pustules → crusts)

• transmisson: activate latent virus (not contagious→ not exposed person can devlop prim chickenpox infection, if in contact with shingles)

• detection: symps, diagnostic tests

• entry: mucus mems

• treatment: antivirals

• vaccine: yes

Viral Respiratory Diseases Leading to Skin Rashes: Measles

• pathogen: measles virus

• s/s: viremia, macular (flat/discoloured lesions), rash on face/extremities, fever, kopliks spots (white spots inside cheek)

• transmisson: direct(more)/indirect/air vehicle

• detection: symps, diagnostic tests

• entry: mucus mems

• treatment: self limiting, care for symps

• vaccine: yes

Bacterial Circulatory Diseases: Toxic Shock Syndrome

• pathogen: S. aureus

• s/s: toxemia, vomit, diarrhea, hypotension → sepsis (excess cytokines → damaging inflammation)

• virluence factors: produce TSST-1 (superantigen exotoxin)

• transmisson: oppurtunistic (existing skin wound/tampons)

• detection: s/s, culture swabs, toxin detection

• entry: parenteral

• treatment: debride infected tissue, vasopressors ↑ bp, antibiotics

Bacterial Circulatory Diseases: Gas Gangrene

(obligate anaerobe + forms endospore)

• pathogen: C. perfringens

• s/s: ischemia (reduced flow), necrosis → pain, gas pockets (from fermentation)

• virluence factors: exotoxins (cytolytic)

• transmisson: oppurtunisitic (wound → blood vessels)

• detection: s/s, culture swabs, toxin detection

• entry: parenteral

• treatment: debridement, amputation, o2 therapy, antibiotics

Viral Circulatory Diseases: Infectious Mononucleosis

• pathogen: Epstein-Barr virus

• s/s: pharyngitis, fever, extreme fatigue (months), lymph node swell

• transmisson: direct contact w body fluids

• detection: s/s, serological tests

• entry: mucus mems

• treatment: self limiting

Viral Circulatory Diseases: Burkitt Lymphoma

• pathogen: Epstein-Barr virus

• s/s: rapid growing tumors

• transmisson: oppurtunisitc (weakened from malaria/hiv)

• detection: biopsy

• treatment: chemo

Viral Circulatory Diseases: HIV Infection

• pathogen: human immunodeficiency virus

• s/s: inital flu like symp, viremia / latent: becomes dormant, no viremia

• virluence factors: targets CD4 receptor

• transmisson: direct/indirect contact w body fluid

• detection: serological tests

• entry: mucus mems / parenteral (needles)

• treatment: antivirals

• complications: untreated → virus reactivated + attacks T cells until IS severly damaged (death from oppurtunistic)

Helminthic Circulatory Diseases: Lymphatic Filiariasis

(nematode)

• pathogen: W. bancrofti

• s/s: target/block lymphphatic vessels → edema/fibrosis (=extreme swelling → never reversed)

• transmisson: vector biological transmission (mosquito transfer larvae)

• entry: parenteral

• treatment: anti helminthic meds

Promote Microbial Growth: Gastrointestinal System

• gi tract = warm/nutrient filled → lrg #’s of norm flora

• ex. Lactobacillus, E. coli

Bacterial Stomach Diseases: Peptic Ulcers

• pathogen: H. pylori

• s/s: nausea, lack appetite, weight loss, dark stool

• virluence factors: urease (produce ammonia → neutralizes tum acid), ulcers (damage stomach lining), maybe stomach perforation/cancer risk

• transmisson: direct (body fluid)/vehicle(contaminated water)

• detection: stool/urease test (radiolabelled urea)

• entry: mucus mems

• treatment: antibiotics

Infections of Lower Intestine

types:

1. infection: pathogen ingested, colonizes/damages (longer incubation, slower progression)

2. intoxication: ingest toxins → damage (symps disapear quick, fever rare)

• s/s: nausea, vomit, diarrhea, fever

• transmisson: food/water vehicle

• detection: stool swab

• entry: mucus mems

treatments:

• oral rehydration therapy: fluid/electrolytes given

• antibiotics: in spec cases (infections)

Lower Intestine Infection: S. aureus

• type of mo: bacteria

• virulence: heat stable enterotoxins (superantigen)

• other: intoxication only, salty/improperly prepared food

Lower Intestine Infection: Shigella spp. (Shigellosis)

• type of mo: bacteria

• virulence: invasive/spreads to neighbouring cells, shiga toxin produced (→ hemorrhaging)

• other: comps = HUS, prevalent in fecal contaminated f/w

Lower Intestine Infection: Salmonella spp.

• type of mo: bacteria

• virulence: invasive, doesnt spread endotoxin

• other: enter blood + persist in body (person=carrier), often in poultry/animals (ex. turtle)

Lower Intestine Infection: E. coli - EPEC

• type of mo: bacteria

• other: travelers diarrhea (fecal contaminated f/w)

Lower Intestine Infection: E. coli - EHEC

• type of mo: bacteria

• virulence: shiga-like toxin

• other: comps= HUS, cant prevent w antibiotics, fecal contaminated f/w (more severe)

Lower Intestine Infection: V. cholerae

• type of mo: bacteria

• virulence: a-b exotoxin (→ extreme loss of ions/water)

• other: severe diarrhea (rice water stools), fecal contaminated f/w after natural disasters, shellfish (biofilm)

Lower Intestine Infection: C. difficile

• type of mo: bacteria

• virulence: 2 toxins → diarrhea, dehydration, appetite loss, abdom pain

• other: HAI/oppurtunistic (LT antibiotic use) + fecal contaminated f/w

Lower Intestine Infection: G. lamblia (Giardiasis)

• type of mo: protozoa

• virulence: attach through adhesive disk (blocks nutrient absorption)

• other: symps last 2-6 weeks or chronic, physcial removal from water (not boiling)

Other Digestive Diseases: Hepatitis A Virus

• disease: hepatitis

• s/s: acute liver inflam → appetite loss, dark urine, abdom pain, gray stool, non spec symp or asymp

pathogenesis:

1. enters blood → spread/reach liver, becomes inflamed) → loss of norm liver func (breakdown bilirubin → jaundice)

2. no further comps, always clear infection

• transmisson: vehicle food (fecal/viral contaminated)

• detection: serlogical test, often undetected

• entry: mucus mems

• treatment: self limiting

• vaccine: yes

Other Digestive Diseases: Hepatitis B Virus

• disease: hepatitis

• s/s: acute liver inflam → appetite loss, dark urine, abdom pain, gray stool, non spec symp or asymp

pathogenesis:

1. enters blood → spread/reach liver, becomes inflamed) → loss of norm liver func (breakdown bilirubin → jaundice)

2. sm amount of patients devlop chronic liver inflam/liver cancer

• transmisson: direct (infected fluid)/indirect (fomites)

• detection: serlogical test, often undetected

• entry: parenteral (indirect), mucus mems (direct)

• treatment: antiviral

• vaccine: yes

Other Digestive Diseases: Hepatitis C Virus

• disease: hepatitis

• s/s: acute liver inflam → appetite loss, dark urine, abdom pain, gray stool, non spec symp or asymp

pathogenesis:

1. enters blood → spread/reach liver, becomes inflamed) → loss of norm liver func (breakdown bilirubin → jaundice)

2. lrg amount of patients devlop chronic liver inflam/liver cancer

• transmisson: direct (infected fluid)/indirect (fomites)

• detection: serlogical test, often undetected

• entry: parenteral (indirect), mucus mems (direct)

• treatment: antiviral

• vaccine: no

Infections of the Nervous System

• blood brain barrier prevents entry into NS

• s/s: severe headache, fever, photophobia, stiff neck

types:

meningitis: inflam of meninges

• transmission: pathogens enter bloodstream after trauma, production of toxins, spread from resp (direct/droplet trransmission) → leads to inflam → pathogen now enters CNS

encephalitis: inflam of brain tissue

Bacterial Causes of Meningitis

• pathogen: N. meningitides

• s/s: petechial rash (doesnt fade when pressed)

• virulence: endotoxins, attachment factors, capsule

• detection: gram neg

• vaccine: yes

also: S. pneumoniae + H. influenzae

Non Bacterial Causes of Meningitis: Herpes, Influenza & Measles Virus

• mo: virus

• s/s: less severe

• mode of transmission: direct/indirect contact

• treatment: self limiting

Non Bacterial Causes of Meningitis: C. neoformans

• mo: fungi

• s/s: asymp in healthy

• virulence: thick capsule prevents phagocytosis

• transmission: vehicle air (in soil/aerosolized pigeon poo)

• detection: serological

• treatment: anti fungal drugs

Non Bacterial Causes of Meningitis: N. fowleri

• mo: protozoa

• s/s: trophozoite parasite enters nasal passage + travels to CNS

• transmission: submersion of head in freshwater

• detection: observe in cerebrospinal fluid

• treatment: anti protozoan drug w theraputic hypothermia → high mortality

Other Disease of Nervous System: Tetanus

• pathogen: C. tetani

• mo: bacteria

• s/s: localized (muscle spasm of spec group) & generalized (spread throughout body → lockjaw, paralysis of resp muscles)

• virulence: tetanospasmin (exotoxin) prevents GABA release (need for muscle relaxation)

• transmisson: direct contact (wounds) & vector biological (animal bites)

• entry: parenteral

• treatment: assisted breathing, wound debridement, antibiotic therapy, anti-toxins

• vaccine: yes

Other Disease of Nervous System: Botulism

• pathogen: C. botulinum

• mo: bacteria

• s/s: abdom cramps, vomit, flaccide paralysis

• virulence: botulism toxin (exo) prevents acetylcholine release (need for muscle contraction)

• transmisson: vehicle food/air, direct contact (iatrogenic botulism)

• entry: mucus mems (foodborne/inhalation) + parenteral

• treatment: anti-toxins

• vaccine: no

Other Disease of Nervous System: Rabies

• pathogen: rabies virus

• mo: virus

• s/s: furious (agitation, hydrophobia, salivation) + paralytic (muscles paralyze → coma)

• virulence: long incubation (longer if bite far from brain), slowly travles to brain/disrupt norm NT func → moves to other tissues

• transmission: vector biological (animal bites)

• entry: parenteral

• treatment: vaccine (slow progression) + antibodies

• vaccine: yes

Bacterial UTI Causes

• pathogen: E. coli, K. spp., P. aeruginosa,

• disease: cystitis (bladder infection), untreated → pyelonephritis / glomerulonephritis (kidney)

• s/s: dysuria (painful), pyuria (pus), hematuria (blood), bladder pain, high urination, back pain (kidney infection)

• transmission: F (fecal contamination, shorter urethra) & M (prostatitis/kidney stones → impact urine drainage, high infection rate)

• detection: swab

• entry: mucus mems

• treatment: antibiotics

Bacterial Diseases of Reproductive: Gonorrhea

• pathogen: N. gonorrhoeae

• mo: bacteria

• s/s: asymp → M (burning pee + discharge) + F (pelvic pain/discharge → PID)

• virulence: fimbriae/endotoxins

• transmission: direct

• detection: swab

• entry: mucus mems

• treatment: antibiotics

• vaccine: no

Bacterial Diseases of Reproductive: Syphilis

• pathogen: T. pallidum

• mo: bacteria

• s/s: stage 1 (painless lession= chancre), 2 (skin rash → latent), 3 (lesions in diff systems cuz of chronic inflam)

• virulence: lipoproteins

• transmission: direct

• detection: swab

• entry: mucus mems

• treatment: antibiotics

• vaccine: no

Bacterial Diseases of Reproductive: Genital Warts & Cancer

• pathogen: human papillomavirus

• mo: virus

• s/s: warts (irregular, soft pink)

• transmission: direct

• detection: pap smear (cells w enlarged nuclei)

• entry: mucus mems

• treatment: warts (removal/topical meds) + cancer (chemo)

• vaccine: yes