1303- spec processing/interpreting (5)

Non-sterile sites

Respiratory

Stool

Wounds

Urine

Drainages, skin surface biopsies, etc

Sterile sites

Blood cultures, CSF, sterile BF (synovial, intraoperative fluids, pleural, peritoneal, pericardial, etc)

Are specimens from sterile sites higher priority?

yes

Bacteremia

bacteria in the blood and can be present w/out disease

Septicemia

bacteria or its toxins found in the blood cause harm to the PT

Fungemia

fungal infection in the blood stream (slower growing)

Signs of bacterial colonization in PT

Org present

No tissue invasion

No symptoms

No inflammatory response

Signs of bacterial infection in PT

Organism invading tissue

Symptoms present

Host immune response

Clinical disease

Wound infection: name 2 gram + cocci

Staphylococcus aureus

Streptococcus pyogenes

Wound infection: name 2 gram - bacilli

Pseudomonas aeruginosa

Enteric gram - bacilli (gut organisms)

Wound infection: name 2 anaerobes

Bacteroides species

Clostrifium species

Stool bacteria: name 3 gram - bacilli

Salmonella

Shigella

Campylobacter

Genitourinary specimens include

Vaginal, cervical, and urethral swabs

Urine (sti testing)

Genitourinary: name a gram + bacteria

Streptococcus agalactiae

-Colonization in pregnancy

What is NAAT used for?

Detecting Chlamydia trachomatis, a common STI

Genitourinary: name a gram - diplococci

Neiseria gonorrhoeae

Genitourinary: name 2 common pathogens

Chlamydia trachomatis

Trichomonas vaginalis

CSF: name 2 gram + cocci

Streptococcus penumoniae

Streptococcus agalactiae

CSF: name a gram - diplococci

Neiserria meningitidits

CSF: name a gram - bacilli

Heamophilus influenzae

vaginitis is caused by what bacteria

vaginitis

Pediatric meningitis is caused by what bacteria

Heamophilus influenzae

Meningococcal meningitis is caused by what bacteria

Neiserria meningitidits

Neonatal meningitis is caused by what bacteria

Streptococcus agalactiae

What bacteria is the most common cause of bacterial meningitis in adults

Streptococcus penumoniae

What bacteria causes dysentery

shigella

what bacteria causes Inflammatory diarrhea

Campylobacter

What bacteria causes foodborne diarrhea

Salmonella

What bacteria is commonly seen in abscesses, colonized on the nose, surgical site infections, endocarditis, severe hospital-acquired pneumonia, post-influenza pneumonia, and can lead to sepsis?

Staphylococcus aureus

What bacteria can cause cellulitis, necrotizing infections, and streptococcal pharyngitis?

streptococcus pyogenes

What bacteria is commonly seen in burn infections

Pseudomonas aeruginosa

What type of bacteria are commonly seen in deep abdominal wounds

enteric gram - bacilli (gut organism)

What bacteria species are commonly seen in deep abscesses?

bacteroides species

What bacteria species are commonly seen in gas gangrene?

clostridium species

Sterile BF: name 2 gram + cocci

Staphylococcus aureus

Streptococcus species

What bacteria is seen in Septic arthritis and post-surgical infections

Staphylococcus aureus

Invasive infections are typical of what bacterial species

Streptococcus species

Sterile BF: name 2 gram - bacilli

Enteric gram neg bacilli (e.g. Escherichia coli)

Pseudomonas aeruginosa

Pseudomonas aeruginosa is usually responsible for what type of infection

Hospital-associated infections

Peritonitis

inflammation of the peritoneum

What bacteria can cause peritonitis?

Enteric gram neg bacilli (e.g. Escherichia coli)

Blood culture: name 2 gram + cocci

Staphylococcus aureus

Coagulase-neg staphylococcus

What bacteria can lead to line-associated infections?

Leads to line-associated infections

Blood culture: name 2 gram - bacilli

Escherichia coli

Klebsiella species

What can E.coli cause?

Urosepsis, abdominal sepsis, UTIs

What bacteria can lead to severe sepsis and complicated UTIs?

Klebsiella species

Lower respiratory: name 2 gram + cocci

Streptococcus pneumoniae

Staphylococcus aureus

What bacteria is the common cause of community-acquired pneumonia

Streptococcus pneumoniae

Lower respiratory: name 3 gram - bacilli

Heamophilus influenzae

Klebsiella pneumoniae

Pseudomonas aeruginosa

What is responsible for ventilator-associated pneumonia?

Pseudomonas aeruginosa

Which bacteria is responsible for severe pneumonia which often hospitalizes PTs?

Klebsiella pneumoniae

Haemophilus influenza can cause what

Bronchitis, pneumonia

Upper respiratory: name 2 gram + cocci

Staphylococcus aureus

Streptococcus pyogenes

Urine: name 2 gram + cocci

Enterococcus species

Staphylococcus saprophyticus

Staphylococcus saprophyticus causes what

UTIs in young women

Enterococcus species causes what?

UTIs, especially hospitalized PTs

Urine: name 3 gram - bacilli

Klebsiella species

Escherichia coli

Proteus species

What kind of UTI do proteus species cause

UTI associated w/ kidney stones

Why do we prioritize sterile specs?

Rapid progression of disease

Immediate impact on therapy

Public health implications

Small amounts of growth may be significant

What to consider before plating a spec

Spec type

Quality

Clinical info

Transport time

Potential contaminants

Name a couple reasons why we process diff specimen types differently

Some sites are normally sterile

Some sites contain normal flora

Some organisms are fastidious

Some infections are life threatening

What 3 things must the micro dppt do prior to receiving any spec?

Ensure there are 2 unique identifiers

Collection date & time are provided

Source matches the spec received and deem it appropriate (or not)

What basic info does the gram stain provide?

Gram rxn

Morphology

Arrangement

Presence of inflammatory cells

What does the gram stain help us do?

Anticipate likely pathogens

Determines urgency

Guides further workup

Name a toxin producers

Clostridioides difficile

Name 3 critical/urgent results requiring immediate communication asap

Positive blood culture

Organisms seen in CSF

Certain high-risk pathogens

Mixed urine growth means

possible contam

Skin flora in blood means

contam or infection

Whats the issue with saliva-heavy sputum

hard to interpret

Name a few reasons why micro results are important

Influences antibiotic choice

Guides infection control

May trigger public health notifications

Affects PT outcomes

Process from IDing to reporting

Results are reviewed

Clinical significance is tested

Susceptibility testing may be performed

A final report is released

ID alone isn't the final step! Reporting is staged

What do preliminary results look at?

Gram stain from sterile sites

Positive blood culture alerts

What do final results consist of?

Organism ID

Susceptibility profile

Interpretation comments (if applicable)

Name a few things you should consider/interpret before releasing results:

Does this organism match the spec site

Is this likely contam

What organisms are likely in a spec

Infection or colonization

What needs to be communicated

Does it fit the clinical picture

Is further workup needed

Encapsulated orgs are common causes of what condition?

meningitis (esp important in the context of CSF)

Do genitourinary sites contain normal flora?

YES, every non-sterile site has normal flora

Clostridioides difficile basics

Antibiotic-associated diarrhea

Toxin-mediated disease

Interpretation considerations when looking at a urine spec

Colony count

Pure vs mixed growth

PT symptoms

Collection method

Where do bacterial toxins come from?

From the bacteria's metabolism

What can bacterial toxins lead to?

Can lead to septic shock w/ fever, chills, lowered BP, respiratory distress, & disseminated intravascular coagulation (DIC)

What 3 things do we check when a blood culture is positive?

Gram stain results: rxn, shape, arrangement

Is this organism usually found here

Does this match the PTs symptoms

Name the yeast species responsible for heavy-hitting invasive fungal infection

Candida species

For blood cultures, a physician can ask for alternate incubation requirements depending on?

Suspect organism, PT symptoms, suspected disease state

How are blood cultures incubated?

automated system continuously monitored/agitated

35-37C incubation for 5 days

When interpreting growth quantities and patterns of gram stains, what should you look for?

How much grew

Pure or mixed

Does it match the site

Does it match the clinical picture

Mixed growth in a sterile BF suggests?

contamination

ANY organism recovered from a sterile site may be clinically significant. T or F

TRUE

When interpreting a positive blood culture, consider:

How many bottles are positive

How quickly did the culture flag as +

Is the organism a common skin contaminant

Does the result match the PTs symptoms

When processing and interpreting PT specimens, you have to consider?

Symptoms

Suspected diagnoses

Hospitalized vs community

Recent antibiotic use

Do hospitalized PT often have diff pathogens than community PTs?

Yes

upper respiratory tract basics

Colonization is common

Clinical symptoms guide significance

lower respiratory tract basics

Fewer normal flora

Growth more likely to be significant

4 things to consider when interpreting respiratory specimens:

Upper rep tract contains normal flora

Spec quality affects results

Hospitalized PTs may have diff pathogens

Colonization is common in ventilated PTs

Do you always start by gram staining when dealing with wound infections?

Yes

Considerations when interpreting wound infection specs

Superficial vs deep infection

Presence of O2 (aerobic or anaerobic)

Normal skin flora vs invasive organisms

Considerations when interpreting stool specimens

Normal intestinal flora is always present

Not all diarrhea is bacterial

Clinical history is critical (travel, food, antibiotics)

Toxin-mediated disease vs invasive infection

Do genitourinary sites require clinical context for interpretation?

YES

Considerations when interpreting genitourinary specs

Site of collection

PT symptoms

Some organisms are colonizers

Some orgs are always clinically significant

Why is CSF high priority and urgently processed?

Bacterial meningitis can progress rapidly

Early ID affects survival

What should you remember when evaluating CSF?

ANY organism is clinically significant

Correlate w/ cell count and symptoms

Immediate reporting is required