Micro – Exam 3

Question Answer
Normal flora of the skin -Staphylococcus epidermitis-Corynebacterium sp. (diptheroids)-Pityrosporum sp. (yeast)
Describe staphylococcus epidermitis Coagulase-negative, gram-positive cocci
Pyoderma Inflammatory bacteria infection that produces painful, pus-filled boils
What causes pyoderma -Staphylococcus aureurs-Streptococci (Group A Strep)
Impetigo Crusty lesions, common form of pyoderma that affects children. Common in hot/humid climates, particularly areas of overcrowding or poor hygiene
What causes impetigo -Staphylococci-Streptococci (Group A Strep)
SSSS Staphylococci Scalded Skin Syndrome
Scalded Skin Syndrome (SSSS) Initial infection occurs, commonly in the oral or nasal cavities, throat, or umbilicus. Toxins produced by S. Aureurs leads to red rash and separation of epidermis.Similar to burns. Seen mostly in children, also in immunosuppressed adults.
What causes SSSS Exfoliated toxins produced by Staphylococcus Aureurs
Erysipelas Superficial cellulitis, involving the epidermis, dermis, and lymphatic channels. Seen in children and older adults. Used to be primarily seen on face, now seen on extremities. Characterized by bright red to crimson skin with a fever.
What causes erysipelas Streptococci (Group A Strep)
How is erysipelas contracted? By direct invasion into connective tissue
Scarlet fever Fine, red, "sandpaper" rash on back
What causes scarlet fecer Streptococci (Group A Strep) Exotoxin
What bacteria is Group A Strep S. Pyogenes
Necrotizing fascitis Soft tissue skin infection (AKA flesh eating bacteria)people who become infected by the bacteria typically have an open wound, chickenpox, or an impaired immune system.The infection may spread quickly and be fatal.Can lead to organ failure
What causes necrotizing fascitis Group A Streptococci Exotoxins
Streptococcal Toxic Shock Syndrome Results from wounds secondary to minor trauma or surgery incisions where bacteria have been able to enter the body.Causes dangerous drop in BP, shock, and damage to the kidneys, liver, and lungs.
Why is it hard to treat Streptococcal Toxic Shock Syndrome The toxin damages the tissues and organs so quickly that treatment is difficult and often too late.
What causes Streptococcal Toxic Shock Syndrome Group A Streptococci
Leprosy is also known as? Hansen's Disease
Leprosy Loss of sensory perception in affected area, long incubation period, multiple pale lesions.Primarily Africa, Southeast Asia, South America
What causes Leprosy Mycobacterium leprae discovered in 1873 (Acid fast bacilli)
Warts Cauliflower-like lesions are often referred to as papillary
How are warts contracted? Contact
What is the treatment for warts Scalpel, laser surgery, cryosurgery, chemical burning with salicylic acid
What causes Warts? Human Papillomavirus (HPV)
Smallpox Fevers, chills, myalgia. Lesions in the epidermis.
Mortality rate of smallpox 35%
What causes smallpox Variola virus
What route is smallpox contracted respiratory route
When did the US stop vaccinating for smallpox 1972
When was smallpox eradicated 1977 in Somalia
When did WHO recommend all countries stop vaccinating for smallpox 1980
Chickenpox Vesicular (small blisters) rash, starts on face and trunk and then spreads to extremities
What causes chickenpox Varicella-zoster virus (human herpes virus 3)
How is chickenpox acquired via inhalation of virus
when is chickenpox vaccinated agains between 12 and 18 months
Shingles Typically affects patients older than 60 years of age, people who had chicken pox before 1 yr of age, and immunosuppressed people. Virus moves to cutaneous sensory nerves (waist, upper chest, back, facial)Pain followed by lesions.
What causes shingles Latent (dormant) infection of varicella
Herpes Simplex Cold sores
What causes herpes simplex Herpes simplex virus type 1
How is herpes simplex contracted Oral and respiratory routes – contact with mucous membranes or abraded skin. Over 90% if US population has been affected.
Measles small, raised, red rash on face and trunk, fever, sneezing, cough
What causes measules Rubeola virus
How long is the measles virus active Measles can remain active and contagious for up to 2 hours in the air or on surfaces.
German measles Small, red, flat rash (face then body)
What causes german measles? Rubella virus
Roseola Fever, rash. 6 months to 3 years of age. Fairly common. most children have had roseola by the time they enter kindergarten. 25% of ED admissions for children >1 year of age.
What causes roseola? Human Herpes Virus 6
Fifth disease is also known as? Erythema Infectiosum
Fifth disease Fever, headache, malaise, myalgia. "Slapped-cheek" rash (fades to fine, lacy rash), decreased RBC count
What causes Fifth disease? Human Parvovirus B19
How is Fifth disease transmitted? Respiratory route
Hand, Foot, Mouth Disease Fever, sore throat, vesicles on tongue, back of hands, feetAbdominal painHeadacheOutbreaks in summer and fall
What causes Hand, Foot, Mouth Disease? Coxsackie virus
How is Hand, Foot, and Mouth Disease transmitted Fecal-oral route
What causes Anthrax? Bacillus anthracis
Woolsorter's Disease A form of anthrax infection acquired by inhalation of spores contain Bacillus anthracis. Pulmonary anthrax fever, malaise, cough, muscle aches NoO rhinorrhea or sore throat. May have nausea and comiting
Malignant pustule Initial cutaneous anthrax lesion
Who is at risk for anthrax? Veterinarian, farmer, hunter, butcher, textile mill worker
Agents used as biological weapons -Bacillus anthracis-Uersinia pestis-Francisella tularensis-Brucella sp.-Smallpox -Encephalitis viruses-Hemorrhagic fever viruses
Conjunctivia Thin membrane that covers the inner surface of the eyelid and sclera
Sclera White outer wall of eye made of tough, fibrous tissue
Trachoma Bacteria infection of the eye that may include symptoms of cloudy cornea, discharge from the eye, swelling of lymph nodes just in front of the ears, swollen eyelids, turned-in eyelashes
What causes Trachoma? Chlamydia trachomatisSerovars A, B1, B2, C
Conjunctivitis is more commonly known as? Pink Eye
Conjunctivitis Crusty eyes, itchy eyes, red eyes, swelling, irritation, burning
What causes Conjuctivitis Chlamydia trachomatisNeisseria gonorrhoeaeHaemophilus influenzaeStreptococcus pneumonia
Otitis Externa An inflammation of the ear canal. May be associated with swimmer's ear
What causes otitis externa? Infection with bacteria or fungus.
Swimmer's Ear An infection of the outer ear canal which runs from your eardrum to the outside of your head. It is often brought on by water that remains in your ear after swimming, creating a moist environment that aids bacterial growth.
What causes infections of the ear? -S. Aeurus-S. Pyogenes (GAS)_Pseudomonas aeruginosa
Otitis media Inflammation of the middle ear
What causes otitis media? Streptococcus pneumoniae and Haemophilus influenza account for 50% of acute otitis media. Also S. Pyogenes (GAS) is a cause.
What are the normal flora of the upper respiratory tract? Staphylococci, steptococci, diptheroids
What are the normal flora of the lower respiratory tract? None
The upper respiratory tract consists of? Nasal cavity, sinuses, pharynx, and epiglottis
The lower respiratory tract consists of? Trachea, bronchi, bronchioles, alveoli
Pharyngitis (Pharyngotonsillitis) Throat pain, fever, postnasal secretions, painful lymphadenopathy. Common in children
What causes phayngotonsiliitis (pharyngitis)? S. Pyogenes (GAS)
What causes Rheumatic Fever? Sequelae Disease (An after effect of a disease) – Follows a Group A Strep infection (such as strep throat or scarlet fever)
Rheumatic fever an inflammatory disease with symptoms of fever, myocarditis, arthritis
What are uncommon bacteria that can cause pharyngitis? -Neisseria gonorrhea-Corneybacterium diptheria-S. Aureus-C. Albicans
Diptheria Fever, headache, sore throat, pseudomembrane formation leading to myocarditis
What causes diptheria Corynebacterium diptheriae
How is diptheria transmitted? Person to person via droplets
What vaccine is used against diptheria? DPT
What viral agents cause sinusitis? Rhinovirus, adenovirus, parainfluenz virus, influenza virus
What bacterial agents cause sinusitis? H. influenzaeS. pneumoniaS. Pyogenes
Epiglottitis painful sore theoat, stridor (high-pitched sound noted during breathing that indicates possible airway obstruction), fever, difficulty swallowing or breathing. May obstruct airway
What causes epiglottitis H. InfluenzaeS. Pneumoniae
Common cold Stuffy nose, sneezing, excess nasal secretions, scratchy throat, headache, malaise
What causes the common cold? Rhinovirus (50% – fall and spring)Coronavirus (20% – winter)AdenovirusHuman meta-pneumovirus (resembles RSV)
When does bacterial diseases of the lower respiratory tract occur? When organisms reach the lower airways by bypassing the mechanical and nonspecific barriers of the upper respiratory tract
Pneumonia Inflammation of the lungs. Symptoms include high fever, chest pain, chills, purulent cough
Mortality rate of pneumonia 5-15% – Pneumonia is usually associated with elderly patients who have heart disease or chronic lung disease, diabetes, cancer
What are the bacterial agents of pneumonia? S. Pneumoniae causes 90% of all pneumonias, with S. Pneumoniae and H. Influenza being the most common BACTERIAL causes of pneumonia in infants, children, and adults.
What kind of patient does H. Influenze cause pneumonia in? Found in patients with cancer, diabetes, poor nutrition
What is commonly found with S. Pneumoniae pneumonia? Blood in sputum
In addition to H. Influenzae and S. Pneumoniae, what als0 can cause pneumonia and in what type of patient? Kiebsiella pneumoniae can cause pneumonia, typically in chronic alcoholics.
What causes walking pneumonia Mycoplasma pneumoniae
Walking pneumonia Gradual onset, nonproductive cough, fever less than 102, sore throat, nasal congestion. Common in children and young adults. Atypical pneumonia presentation, more symptoms of pneumonia but with less sputum.
What is walking pneumonia also referred to? Mycoplasma pneumonia
Chlamydia pneumoniae Atypical pneumonia, clinically resembles mycoplasma infection. Symtoms include hoarseness, headache, scant sputum, no fever, persistent cough, malaise.
Legionanaires' Disease is cause by? Legionella pneumophila
Legionnaires' Disease High fever (102-105), chills, chest pain, nonproductive cough, WBCs only slightly elevated, 50% cases have headache, lethargy
What percent of legionellosis cases are hospital acquired? 25%
Where is Legionnaires' Disease found Natural and artificial waters
When/Where did Legionnaires' Disease get it's name? In the 1976 American Legion Convention in Philadelphia where many people who attended the convention contracted the disease
Environmental sources implicated in Legionnaires' Disease Air-cooling systemsRespiratory therapy devicesWhirlpool spasGrocery store mist machinesSaunasShowers
Where does the bacteria for Legionnaires' Disease grow best? It grows naturally in the environment, usually water. It grows best in warm water, like the kind found in hot tubs, cooling towers, hot water tanks, large plumbing systems, pr [art of the air-conditioning systems of large buildings
Pontiac fever Milder infection caused by the same bacteria in Legionnaires' Disease. The symptoms usually last for 2-5 days and may also include fever, headaches, and muscle aches. However, there is no pneumonia. Symptoms go away on their own without treatment
What causes Pontiac fever Legionella pneumophila
Pertussis is also known as Whooping cough
Pertusis Early infection resembles a URI. A rapid adenotest differentiates. Usually no fever, fits of coughing, followed by vomiting. Whooping sound caused by forceful inhalation of air through narrow airway
What is the pathogenesis of pertussis? The pertussis toxins damage epithelial cells and impair immunity
What causes pertussis Bordetella pertussis
What are complications of pertussis? Pneumonia, diaphragm rupture, eye hemorrhages. Cerebral hypoxia and toxic encephalopathy
What kind of specimen collection is used for pertussis? Nasopharyngeal swabs – calcium alginate swab
What form of plate is used in pertussis? Bordet-Gengou or Regan-Lowe(if shipping is delayed)
What type of treatment is used for pertussis? Macrolide antibiotics and isolation
What causes tuberculosis Mycobacterium tuberculosisMycobacterium avium-intracellulare
Tuberculosis (TB) Chronic pneumonia with productive cough, fever, cills, malaise, weight loss, most important cause of chronic pneumonia globally
How many annual deaths worldwide is caused by TB? 3 million
TB Resistance TB can be Multi-drug resistance. Resistant to at least two of the main first-line TB drugs such as Rifampin, isoniazid, and kanamycin. WHO estimates 500k drug-resistant cases/year
XDR TB Resistant to front-line drugs and also 3 or more of the second-line drugs. 2-19% of cases
Mortality rate of Woolsoreters' Disease?
RSV Disease respiratory syncytial virus, coughing, wheezing, outbreaks in the winter and spring
How many US deaths are from RSV 4500/year
What is the #1 cause of pneumonia in children less than 6 months of age? RSV
Human Metapneumovirus Resembles RSV, 2nd only to RSV as a cause of severe lower respiratory tract infections in the young
Influenza Fever, chills, headache, muscle aches. Cold-like symptoms (nasal congestion, sore throat) appear as fever subsides.
What is the most common viral cause of pneumonia? Influenza virus
Influenza virus strucutre H#N# – H Spikes = Hemagglutinin, which allows the virus to recognize and attach to cellsN Spikes = Neuraminidase, which helps the new virus to release from host cells.
Antigenic drift Small, gradual changes that occur through point mutations in the two genes that produce H-spikes and N-Spikes (results in minor changes to these surface proteins)
Antigenic shift Produces new virus strains that may not be recognized by antibodies to earlier influenza strains (Main reasons why people can become infected with influenza viruses more than one time)
Hantavirus Pulmonary Syndrome Fever, myalgia, headache, nausea, vomiting, abdominal pain, pulmonary edema, and respiratory failure
Mortality rate on Hantavirus Pulmonary Syndrome 30-34%
How is Hantavirus Pulmonary Syndrome transmitted? By contact or inhalation from infected deer mouse
What was the well known outbreak of Hantavirus Pulmonary Syndrome 1993 outbreak in Navajo In Four Corners (AZ, NV, CO, NM) (80% mortality rate)
When should you consider Hantavirus Pulmonary Syndrome (HPS)? If patient was exposed to rodents.
We are SARS free, but now we have? MERS
What is crucial when dealing control of infections in the lab/health care Effective sterilization and disinfection
Sterilization Destruction of ALL forms of life, including spores (Chemical or physical methods)
Disinfection Removal of pathogenic organisms, NOT NECESSARILY ALL SPORES (Chemical; inanimate objects)
Antiseptic A substance applied to the skin for the purpose of eliminating or reducing the number of bacteria; does not kill spores
Factors that play a role in the selection and implementation of disinfection: -Type of organism-Number of organisms (microbial load)-Concentration of disinfecting agent-Presence of organic material-Composition of surface
Type of organism Am I dealing with resistant organisms (bacillus-spores, m. tuberculosis-mycolic acid, etc) Some can withstand chemical and physical treatments
Number of organisms Microbial load determines other factors because composed of organisms that have varying degrees of susceptibility
Concentration of disinfecting agent Organic material can inactivate disinfecting agents. All agents have an efficient concentration that they decrease or kill micro-organisms at. Most are more efficient in water.
If organic material is present protect from exposure, neutralize action
Composition of surface will the agent damage the surface
Factors to consider before selecting disinfectant -contact time-temp-pH-Biofilms-Compatibility of disinfectants
Contact time determined by size of clean-up, suspected organisms, composition of object, presence of organic material
Termperature some organisms are less active in cold, others destroyed by heat, and may dry agent up
pH All disinfectants have an optimal ph
Biofilms Organisms living in communities. They provide protection against chemical and physical means of destruction
Compatibility of diseinfecants Wrong combination can cause dangerous fumes.
Methods of sterilization AutoclaveFiltrationRadiationGas-Ethylene Oxide
Autoclave Moist heat vs. dry heat, creates steam, can be slow exhaust or rapid
Filtration Heat-sensetive items
Radiation Ionizing-high energy and short wavelength. Protect eyes and monitor UV output
Gas-ethylene oxid Aerate, delicate instruments (Gaseous sterilization)
Lab Autoclave Time, Temp, Atmosphere 121 degrees C, 15 lb pressure, 15 minutes
OR Autoclave Time, Temp, Atmosphere 133 degrees C, 32 lb pressure, 3 minutes
Central Supply Autoclave Time, Temp, Atmosphere 135 degree C, 32 lb pressure, 10 minutes
Antiseptics Surgical scrub/Handwashing
Action of antimicrobial drugs Bactericidal/Bacteriostatic
Bactericidal Kills organism
Bacteriostatic Inhibits growth
Mechanisms of antimicrobial agents Inhibits cell wall synthesisInjure cell membraneInhibition of folic acid synthesisInhibition of DNA synthesisInhibition of protein synthesis
Inhibition of cell wall synthesis B Lactams (PNC and Cephalosporins) – results in deficient cell wallsVancomycin – Interferes with formation of linear strands of peptidoglycan
B Lactams Penicillin and Cephalosporins, prevents the final cross-linking of peptidoglycan
Injury to cell membrane Polymyxins Attaches to phospholipid of membrane resulting in changes in membrane permeability
Inhibition of Folate synthesis Folic acid pathway provides precursor molecules for DNA synthesis
Sulfonamides Resembles PABA, Inhibit Dihydrofolate
Trimethoprim Resembles DHFA, Inhibit tetrahydrofolate (THFA)
Inhibition of folic acid synthesis Trimethropim-sulfamethoxazole (Syngergism, if used in combination, only 10% is needed compared to each drug alone) (AKA Septra or SXT)
Inhibition of DNA Synthesis Naladixic acid and ciprofloxacin – Inhibit DNA gyrase, result in breakage of DNA structure)
DNA gyrase Controls the structure/interconnections of bacterial DNA
Inhibition of RNA synthesis Rifampin, Inhibit RNA polymerase (interferes with mRNA production)
RNA polymerase Mediates transcription of template DNA into functional RNA
Inhibition of Protein synthesis Bind to 30s ribosomes, cause error in reading of mRNA/Bind to 50s ribosomes, inhibit formation of peptide bonds
Factors leading to antibiotic resistance overuse/misuse of antibiotics by Drspatient demand for antibioticsFailure of patients to follow treatment planLong-term, low-dose treatment for acneworld traveluse of antibiotics in animal food
Susceptibility testing Tube or plate dilution methodMinimum Inhibitory ConcentrationMinimum Bactericidal Concentration
Minimum Inhibitory Concentration (MIC) Lowest concentration of antimicrobial that inhibits growth
Minimum Bactericidal Concentration (MBC) Lowest concentration of antimicrobial that results in >99.9% killing
Disk-Agar Diffusion (Kirby Bauer) Susceptible – Zone of growth inhibitionResistant – No growth inhibitionIntermediate – Some growth inhibition

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