Phenotype methods include the examination of both microscopic (staining of specimens) and macroscopic (observing colonies in a petri dish) morphology

Types include direct staining (gram, acid fast, direct antibody) and isolation media (blood agar, mcconkey agar, mannitol salt agar), biochemical tests (carb. fermentation, hydrolysis, enzyme function, rapid test) and also phage typing

Phenotype methods

Genotype methods

Immunological methods

Genotype methods include the examination of Nucleic acid sequences to determine a strain(s) of microorganisms

They include genetic probes, nucleic acid synthesis, polymerase chain reactions, G&C base composition

Immunological methods include testing for the antibodies to a specific antigen in the patients blood. These are most widely used.

They include agglutination & precipitation reaction, western blotting, complement fixation, immunofluorescence testing, enzyme linked immunolsorbent assay (ELISA)

Name the three layers of the skin

Epidermis- outer, keratinized layer

Dermis- middle layer, capillary beds, nerve endings

Subcutaneous layer- inner, fatty layer where blood vessels and muscels orginate

1. Its in direct contact w/environment

2. Part of the integumentary  system which also    includes hair, sweat, and oil glands

3. It has diff. mechanisms to prevent pathogen colonization like sweat which maintains a low pH & creats a high salt concentration environment

4. Lysozyme is found in both sweat and tears

Diphtheroids (club shaped bacteria)

Micrococci ( staph & microccus)

Yeast (candida albicans)

Impetigo is a highly contagious superficial bacterial infection that causes the skin to peel or flake off.

Its caused by direct, indirect contact with either staphylococcus aureus and / or staphlyococcus pyogenes.

Children are the primary victims.

SSSS is caused by S. aureus and effects mostly newborns.

Its an exotoxin mediated disease and the phage encoded exfoliative toxins A and B are responsible for damage. These toxins cause bullous lesions first appearing around the umbilical cord. The lesions begin as red areas that then take on the appearance of wrinkled tissue paper.

Gas gangrene is caused by gram positive, endosprore forming bacterium called Clositridium perfringenes. These spores can be found on the skin, in soil, in the intestines and vagina.

There are 2 forms in anaerobic cellulitis, the bacteria is spread within damaged necrotic muscle tissue, producing toxin and gas and stays localized.

In true myonecrosis the pathology is more destructive. Toxins produced in lg muscles can diffuse into  nearby healthy tissue and destroy it. It can progress through an entire limb or bodyy area.

Impetigo caused by S. aureus

Virulence factors?

Culture / diagnosis?

Prevention?

Treatment?

Distinguishing features?

Impetigo S. aureus

Virulence factors - exfoliative toxin A, coagulase, other enzymes

Culture / diagnoses - culture and Gram stain, coagulase and catalase tests

Prevention - good hygiene practices

Treatment - topical  mupirocin, oral cephalexin

Distiguishing features - seen more often in older children and adults

SSSS

(Staphylococcus Scalded Skin Syndrome)

Causitive organism?

Modes of transmission?

Virulence factors?

Culture / Diagnosis?

Prevention?

Treatment?

Distiguishing features?

Staphylococcus Scalded Skin Syndrome

Causitive organism - S. aureus

Mode of transmission - direct or droplet contact

Culture / diagnosis - histological sections, cultures preformed but false negatives are common

Prevention - eliminate carriers in contact w/neonates

Treatment - systemic antibiotics (cloxacillin or cephalexin)

Distiguishing features - split in skin occuring within the epidermis

Gas Gangrene

Causitive organism?

Mode of transmission?

Virulence factors?

Culture / diagnosis?

Prevention?

Treatment?

Gas Gangrene

Causitive organism - Clostridium perfringens

Mode of transmission - vehicle (soil), endogenous transfer from skin, GI tract, reproductive tract

Virulence factors - alpha toxin, exotoxins, enzymes, gas formation

Culture / diagnosis - Gram stain, CT scans, Xray

Prevention - clean wounds, debride dead tissue

Treatment - cephalosporin, surgical removal, oxygen therapy

Hansens disease is a chronic, progressive disease of the skin and nerves known for its extensive medical and cultural ramifications.

Its characterized by asymmetrical, shallow skin lesions containing very few bacteria.

Hansens Disease (leprosy)

Causitive organism?

Transmission?

Virulence factor?

Culture / diagnosis?

Prevention?

Treatment?

Hansens disease (leprosy)

Causitive organism - Myobacterium leprae

Transmission - not clear, possible direct or droplet contact, mechanical vector

Virulence - binding to Schwann cells, ability to survive w/in macrophages

Prevention - isolation of infected people, chemoprophylaxis of contacts

Treatment - multidrug including rifamphin and dapsone

Chickenpox

Causitive organism?

Transmission?

Virulence factor?

Culture / diagnosis?

Prevention?

Treatment?

Distinguishing features?

Chickenpox

Causitive organism - human herpes virus

Transmission - droplet contact, inhalation of lesion fluid

Virulence factor - ability to fuse cells and remain latent in ganglia

Culture / diagnosis - clinical appearance

Prevention -  Live attenuated vaccine

Treatment -  none in uncomplicated cases, acyclovir for high risk

Distinguishing features - no fever prodrome, lesions are superficial

Smallpox

Causitive organism - variola virus

Transmission- droplet contact, indirect contact

Virulence factor - ability to dampen, avoid immune response

Culture / diagnosis - clinical appearance

Prevention - live virus vaccine

Treatment - N/A

Distinguishing features - fever precedes rash, lesions are deep

Measles

Causitive organism - measles virus

Transmission - droplet contact

Virulence factor - syncytium formation, ability to suppress CMI

Culture / diagnosis - ELISA for IgM, acute / convalescent IgG

Prevention - live attenuated vaccine (MMR)

Treatment - no antivirals, vitamin A, antibiotics for secondary infections

Distinguishing features - starts on head, spreads to whole body, last over a week

Warts

Causitive organism - human papillomaviruses

Transmission - direct contact, autoinoculation, indirect contact

Virulence factors - N/A

Culture / diagnosis - clinical diagnosis, histology, microscopy, PCR

Prevention - avoid contact

Treatment - home treatments, cryosurgery

Leishmaniasis

Causitive organism - leishmania spp

Transmission - biological vector

Virulence factor - multiplication w/in macrophages

Culture / diagnosis - culture of protozoa, microscopic visualization

Prevention - avoiding sand flies

Treatment - pentastam

Distiguishing features - mucocutaneous and systemic forms

Ringworm is typed by location

Treatment is in general is through the use of antifungals and the avoidance of dermatophtes

Conjunctivitis - pink eye caused by either bacteria or viruses

CNS (central nervous system) which includes the brain and spinal cord

PNS (peripheral nervous system) which consists of all of the nerves

1. Sensory function

2. Integrative function

3. Motor function

Meningitis is the inflammation of the meninges. The diagnosis involves a lumbar puncture and an analysis of the cerebral spinal fluid.  The brain and spinal fluid are normally sterile environments.

Treatment - most often done w/ broad spectrum antibiotics but there are exceptions depending on the causitive agent.

Symptoms - headache, painful or stiff neck, fever and WBC's w/in the cerebral spinal fluid

Neisseria meningitidis - petechiae are red dots on skin; treatment is broad spectrum antibiotics

Streptococcus pneuoniae - a hemolysin breaks down RBC's

Cryptococcus neoformans- treatment- antifungals

Aseptic meningitis- cause by viruses; when meningitis is evident but there are no bacteria or fungus in cerebral spinal fluid, it is viral.

Neonatal meningitis

Menigoencephalitis is caused by two microorganisms, both amoebas.

Naegleria fowleri- a small flask shaped amoeba that moves by means of a single broad pseudopod. It forms a rounded thick walled uninucleated cyst that is resistant to extreme temps and mild chlorination. Most cases have been due to swimming in warm, natural bodies of fresh water.The "eyes" and "mouth" of its facelike appearance are its attachment and feeding structures

Subacute encephalitis

Prions

Prions are infectous protein particles that contain no genetic material 

They can cause Transmissible Spongiform Encephalitis (TSE)

Name the human TSE's

(Transmissible Spongiform encephalitis)

Human TSE's are:

Creutzfeldt-Jacob

Gerstmann-Strussler-Scheinker

Fatal Familial Insomnia

These diseases cannot be diagnosed until after the death of the patient b/c the brain must be examined. The brain would show spongiform lesions.

Creutzfeldt-Jacob disease

Creutzfeldt-Jacob disease or Mad Cow disease (goat=scrappies) comes from contaminated meat that has been in contact with cerebral spinal fluid from an infected cow

Rabies

Rabies has an enveloped glycoprotein which makes it more resistant.

Negri bodies are intercellular inclusions in the brain

Tetanus

Tetanus, or lockjaw - the neurotoxin prevents the muscle from relaxing after a contraction. The toxin (protein) must eventually degrade and then the release from contraction will occur.

Botulism

Botulism is different from Tetanus because it causes flaccid paralysis (normal contractions cannot occur b/c of binding at the neuromuscular junction). This binding prevents contraction.