Microm 442 Final

Pseudomonas gram, shape, movement, environment, pathogen type

• Gram -

• Rods

• Often flagellated

• Water, soil, air, contaminants in labs

• Opportunistic

P. aeruginosa gram, shape, hemolysis, oxidase, temp, smell, pigment

• Gram -

• Long narrow rod

• Beta hemolytic

• Oxidase +

• Growth at 42 C (ideal at 37 C)

• Grape or corn chips

• Pyocyanin + pyoverdin - blueish green Pyorubin - red brown

P. aeruginosa diseases

• Hot tub folliculitis: infection of hair follicle root via contaminated water

• Swimmer’s ear: infection of external ear canal skin via contaminated water

• Predominant lung pathogen in those w/ CF, different genetic sub-lineages evolve over time

Cystic Fibrosis cause & treatment

• Mutation in CFTR protein that modulates water and Cl out of cells leading to inefficient pumping & thick mucinous secretions

• Antibiotics, lung transplant, CFTR modulator therapy

P. aeruginosa virulence factors

• Biofilm: collection of bacteria held together by matrix made of alginate & proteins

  • Lead to increased antibiotic resistance via changes in bacterial gene expression & nutrient limited in center core

• Mucoid: Overproduction of alginate that makes capsule around bacteria

  • Lead to protected microcolonies (small # act same as large #)

Bacterial genomics & pan-genome (P. aeruginosa)

• Entire genes can be absent/present in different strains from same species

  • some always found (core), some variably found (accessory)

• Pan-genome: entire possible genetic content of a bacterial species

• P. aeruginosa: antibiotic resistance, metabolic, virulence genes are large fraction of accessory genome

Mycobacterium identification/characteristics

• Acid fast staining: look pink/red due to dye penetrating waxy cell wall (acid fastness)

• Distinctive pigments from carotenoids

• Fastidious: slow growing and difficult

  • Can grow to high densities before immunity develops

• Difficult to culture in vitro & genetically manipulate

TB & HIV connection

• TB is highest in areas with endemic HIV

• HIV increases susceptibility to TB & worsens outcomes via T cell depletion

TB transmission

• Respiratory droplets

• Penetrate alveoli

• Requires prolonged, recurrent exposure for infection

TB pathogenesis & reactivation

• Ingested by macrophages → replicate in macrophages & destroy them → attract more cells → get ingested & repeat

• Reactivation: often occurs w/in 2 years in top of lungs, HIV is common cause

TB treatment

• 3 agents for disease due to high rates of resistance & bacterial burden

• Single agent used for exposure & no disease, low bacterial burden

Leprosy origin, hosts, incubation,disease

• First bacterium identified to cause disease in humans

• Human, primates, armadillos, Eurasian squirrels

• 2-10 year incubation period

• Low skin burden: tuberculoid, localized lesions

• High skin burden: Lepromatous, multiple lesions

Leprosy transmission, pathogenesis, treatment

• Aerosol route, animal & soil exposure, genetic predisposition

• Tropism for Schwann (nerve) cells, taken up by macrophages via complement receptor

• Multidrug therapy → infectiousness usually lost w/in 3 days

Other human mycobacterial infections

• M bovis: can cause tuberculosis

• M. kansasii & M. avium-intracellulare: tuberculosis like respiratory disease

• M. foruitum, marinum, ulcerans: skin & soft tissue infections

Haemophilus spp gram, shape, culture, CO2 %, motility/spore

• Gram -

• Coccobacilli or short rods

• Chocolate agar due to fastidious (need X & V factor)

• Facultative anaerobe, 5% CO2

• Non motile/spore

H. influenzae types

• Encapsulated: Type B (vaccine preventable, Hib), uncommon, BSI

  • Hib vaccine: conjugate PRP capsule to carrier protein to stimulate I/S

• NTHI (non encapsulated): nasopharyngeal colonizer, most common, pneumonia

H. influenzae virulence factors & treatments

• Capsule (Type B) & adhesins (protein E, OMP2, type IV pilus)

• Amoxicillin or IV abx if severe (ceftriaxone)

Other respiratory Haeomphilus spp

• H. aegyptius: conjustivitis

• H. parainfluenzae: AOM, sinusitis

• H. haemolyticus: invasive disease

H. ducreyi infection, transmission, treatment (chancroid)

• STI w/ multiple lesions

• Heterosexual transmission, low SES

• Azithromycin or ceftriaxone

Bordetella spp gram, shape, culture, O2, protection, transmission

• Gram -

• Coccobacilli or short rods

• Regan-Lowe culture (silvery) due to fastidious

• Strict aerobe

• Encapsulated

• Adults & adolescents are reservoir; disease in unimmunized (young/immunocompromised)

Clinical Pertusis & treatment

• Whooping cough (LRT), CFUs decrease over time, infectious for 3 weeks

• Macrolides, intubation/ventilation

Bordetella virulence factors

• Adhesions

  • Filamentous hemagglutinin (FHA)

  • Fimbriae

  • Pertactin

• Toxins

  • Adenylate cyclase toxin

  • Pertussis toxin

  • Tracheal cytotoxin

Zoonotic modes of acquisition

Skin contact, arthropod vector, inhalation, ingestion

Plague (Yersinia pestis): gram/shape, virulence factors, reservoirs, transmission, diagnosis, disease, treatment

Characteristics

• Gram negative rods w/ bipolar staining

Virulence

• Hms & Ymt promote biofilm formation & obstruction of flea gut

• Pla for host tissue spread

• YOPs injected by T3SS block phagocytic cells

Transmission

• Black rats, prairie dogs, other rodents

• Fleas and lice to humans

Diagnosis

• Gram stain/culture of Bubo

Disease

• Bubonic, Septicemic, Pneumonic

Treatment

• Doxycycline, fluoroquinoles

Tularemia (Francisella tularensis): gram/shape, virulence factors, transmission, diagnosis, disease, treatment

Characteristics

• Gram negative coccobacillus

Virulence

• LPS doesn’t stimulate IS

• Represses inflammasomes & cytokines

• T6SS to replicate in macrophage cytoplasm & kill

Transmission

• Arthropod vectors or rabbits/dogs

Diagnosis

• Culture w/ cysteine, serology

Disease

• Ulcero/oculo glandular

Treatment

• Doxycycline, fluoroquinoles

Brucellosis (Brucella): gram/shape, virulence factors, transmission, diagnosis, disease, treatment

Characteristics

• Gram negative coccobacillus

Virulence

• T4SS allow replication in ER vacuole in phagocytes

• LPS w/ O side chain prevents host defense activation

Transmission

• Unpasteurized dairy products

Diagnosis

• Bone marrow/blood culture

Disease

• Undulant fever/flu, bones/joints, CNS

Treatment

• Doxycycline & aminoglycoside/rifampin

Capnocytophaga canimorsus: gram/shape, virulence factors, transmission, diagnosis, disease, treatment

Characteristics

• Gram negative bacillus

Virulence

• Unusual iron transport system

• Resistant to serum & neutrophil uptake

Transmission

• Cats & dogs

Diagnosis

• Blood smear

Disease

• Sepsis w/ DIC

Treatment

• Beta lactams

Pasteurella multocida: gram/shape, virulence factors, transmission, diagnosis, disease, treatment

Characteristics

• Gram negative coccobacillus

Virulence

• Phage encoded toxin

• Capsule

• Iron/nutrient uptake

Transmission

• Fowl, cats, dogs

Diagnosis

• Blood/chocolate agar, mousey odor

Disease

• SSTI, osteomyelitis

Treatment

• Beta lactams, fluoroquinoles

Rat bite fever (Streptobacillus moniliformis): gram/shape, transmission, diagnosis, disease, treatment

Characteristics

• Gram negative rod

Transmission

• Rats, contaminated water/unpasteur milk

Diagnosis

• Broth - puff balls

• Has anticoagulant so blood culture doesn’t work

Disease

• Fever, migratory polyarthralgias, rash

Treatment

• Penicillin

Anthrax (Bacillus anthracis): gram/shape, virulence factors, transmission, diagnosis, disease, treatment

Characteristics

• Gram positive rod, spore forming

Virulence

• Anthrax toxin: lethal (heart/blood vessel/muscle) & edema factor (liver, depletes ATP via cAMP conversion)

• Antiphagocytic capsule

Transmission

• Herbivore contact, woolsorter’s disease, any infected animal product; no person-person

Diagnosis

• Gram stain - glass appearance/tacky, chest x-ray/CT

Disease

• Cutaneous (majority) - ulcers, lower mortality

• Gastrointestinal - vomiting/diarrhea, high morality

• Inhalational - inhale spores, breath/lung issues, high mortality

Treatment

• Fluoroquinole + carbapenem + linezolid/doxycycline

Myco & Ureaplasma identification

• Fastidious: rich medium w/ serum, small colonies

  • M. pneumoniae takes several weeks to grow

• PCR, serology

Animal bites w/ Mycoplasma: species & infection

Mycoplasma are commensals in mammals, often harmless

M. phocimorsus can cause aggressive infection, fails beta lactam therapy

Mycoplasma & Ureaplasma virulence factors

Myco

• P1 adhesin

• CARDS toxin - ADP ribosylation

Urea

• IgA protease

• Urease → ammonia

• MB (surface lipoprotein)

Myco & Ureaplasma diseases & treatment

• UTI (hominis), non gonococcal urethritis (genitalium), neonatal/post partum fever

• Azithryomycin, oral tetracyclines, no vaccine

Legionella gram, coloring, energy source, identification

• Gram negative

• Hard to stain, grey/white colonies (cut glass)

• Asaccharolytic (energy from amino acids, not carbs), L-cysteine

• Buffered charcoal yeast extract, urine antigen test (only L. pneumophila sero 1)

Legionella pneumophila reservoirs & transmission to humans

• Parasite of amobae, biofilm in water/AC towers

• Aerosolized H2O, inhalation, invades & lives inside phagocytes

Legionnaires disease: disease, cause, mortality/attack rate, children

• Bacterial pneumonia

• Aerosolized water

• High CFR (~10%), high attack rate

• Very rare in kids

L. pneumophila Pontiac Fever disease, mortality/attack rate, children

• Upper respiratory infection, not pneumonia

• High attack rate, non fatal

• Children do get infected

L. pneumophila virulence factors

• Adhesins: Type IV pili, OMP

• T4SS

  • Entry into host cell → hijack phagosome & form LCV → escape via apoptosis