micro 2 lower respiratory tract and others

consist of lower respiratory tract


the 2 major connections between the body's interior and exterior

respiratory and GI tracts

the smallest branches of bronchi



surviving or growing on host tissue without causing overt harmful effects


finger like protein surface structures that help gram neg bacteria adhereEnterobacteriaceaeLegionella spp. Pseudomonas spp.


another name for fimbriae but technically the term for a similar structure used in sexual interaction rather than just adherence

Corynebacterium diphtheriae growth causes what?

diphtheritic (pseudo) membrane-causes necrosis and sloughing of the epithelial mucosa-may extend from anterior nasal mucosa to bronchi

mycobacterium tuberculosis is the classic representative of what kind of pathogen?


How does one get infected with primary tuberculosis?

the organism is carried to an alveolus in a droplet nucleus (a tiny aerosol particle containing a few tubercle bacilli)

RSV accounts for 40-80% of cases of bronchiolitis and is caused primarily by what?


empyema definition

pus in a body cavity due to an organism infecting the it through gaining access through a fistula

Community -Acquired Pneumonia info

-6th leading cause of death in the US-number 1 cause of death from infectious diseases in the US-more than 80% of pneumonias in infants and children are caused by viruses

The cause of acute pneumonias is strongly dependent on what?

age of patient

What is the most common causes of bacterial pneumonia in school age children (5-14)?

M. pneumoniae and C. pneumoniae

What is the most common etiologic agent of LRT infection among adults under 30 years old

mycoplasma pneumoniae-transmitted via close contact

regardless of age or coexisting illness, what is the most prevalent cause of LRT?

Streptococcus pneumoniae

What is the leading cause of death among patients with nosocomial infections?

pneumonia-Hospital, ventilator and healthcare associated pneumoniae

Early onset pneumonia info

-occurs within first 4 days of hospitalization-carries a better prognosis

late onset pneumonia info

-occurs after more than 5 days of hospitalization-caused by multi-drug resistant organisms

The most common opportunistic infection among AIDS patients in the US:

Pnaumocystis (carinii) jiroveci pneumonia (PCP pneumonia)

What sample provides the primary means of determining the causes of bacterial pneumonia

expectorated sputum

Even though it is one of the most numerous and time consuming specimens in the micro lab for culture, sputum is among the what in specimens?

least clinically relevant

What should a patient do before providing a deep-coughed specimen?

rinse the mouth with saline or water

What is one of the most important uses of the gram stain?

to evaluate the quality of expectorated sputum received for routine bacteriologic culture.

Media to use for LRT culture

5% sheep blood agarMacConkey agarchocolate agar

Media for use in suspected cases of Legionnaires' disease

buffered charcoal yeast extract agar


infection within subarachnoid space or throughout the leptomeninges (arachnoid and pia)

An infection involving the CNS is considered what?



4 large, fluid-filled spaces within the brain

Choroid plexus

specialized secretory cells in 3rd and 4th ventricles that produce CSF

Aseptic Meningitis is characterized by what?

increased lymphocytes and other mononuclear cells in CSF-commonly associated with viral infections

Purulent Meningitis

-Bacterial-marked, acute inflammatory exudate with large numbers PMN's

What causes purulent meningitis in children?

Haemophilus influenzae type B

What causes purulent meningitis in young adults?

Neisseria meningitidis

What causes purulent miningitis in adults?

Streptococcus pneumoniae

What should you never do to CSF culture that will kill the 3 meningitis bugs in it?

refrigerate it

Acute meningitis diagnosis

-large numbers of inflammatory cells (mostly PMN's)-decreased glucose relative to serum glucose in CSF-increased protein concentration in CSF


an inflammation of the brain parenchyma- viral

What is almost always the first step in the workup of a patient with suspected CNS infection?

lumbar puncture (spinal tap)

3-4 tubes of CSF specimen be hand delivered where?

tube 1- chemistries (glucose protein)tube 2- micro (gram stain, culture)tube 3- cell count and differential (hemo)tube 4- other testing if needed (not always collected)

What must be performed on ALL CSF sediments?

gram stain

What is an excellent tool to use for slide making of CSF?

cytospin centrifuged CSF specimen

Latex agglutination testing for capsular antigen is more sensitive and specific so _____ is recommended in place of an India ink stain?

antigen testing


tough, white of the eye


anterior portion of sclera, transparent, no blood vessels

aqueous humor

clear and watery filling the anterior cavity


caused by Chlamydia trachomatis and is one of the most important types of conjuctivitis and leading causes of blindness in the world


-emergency, can lose eye within 24 hrs-caused by Pseudomonas aeruginosa or Staph aureus or HSV

otitis externa

external ear infection-acute or chronic

another name for acute diffuse otitis externa

swimmer's ear-related to maceration (softening of tissue) of the ear from swimming and or hot humid weather

What is one of the most common causes of respiratory tract infection and in most cases resolves without treatment?

Acute viral sinusitis

The major bacterial pathogens in adults with acute sinusitis

S. pneumoniaeH. influenzae

Most common acute sinusitis causing pathogens in children

S. pneumoniaeH. influenzaeM. catarrhalis

upper respiratory tract infections are considered what?

self limiting and caused by viruses

croup symptoms

stridor - difficulty in moving in enough air through larynxbarking- nonproductive cough-usually caused by bacteria

Primary cause of bacterial pharyngitis

Strep pyogenes-or group A beta hemolytic streptococci

Infection with S. pyogenes can lead to what?

post-streptococcal sequelae(acute rheumatic fever and glomerulonephritis)(diseases that follow a streptococcal infection)

Vincent's angina

acute necrotizing ulcerative gingivitis (tench mouth)


common cold- usually caused by viruses

Hallmark for diphtheria

an exudate or membrane usually on the tonsils or pharyngeal wall

What is the gray-white membrane from with diphtheria?

from diphtheria toxin

S. pyogenes specimen storage

-stays viable on a dry swab for up to 48-72 hrs-resistant to desiccation (drying)-other specimens need to be transported in media to prevent drying

All specimens with a negative direct antigen test for group A streptococci should be cultured or confirmed using what?

nucleic acid method

The primary cause of bacterial pharyngitis in north america

S. pyogenes (beta hemolytic group A strep)

presumptive ID of S. pyogenes can be made after overnight incubation using by placing what directly over the area of initial inoculation?

.04 unit differential Bacitracin filter paper disk(Taxo A, BBL, or Bacto Bacitracin)