Basic Microbiology - Specific Microbes

Gram + coccus appearing in clusters

Identify the appearance and characteristics of staphylococci (Gram reaction, shape of cells, and arrangement of cells)

easy

Staphylococci are easy/hard to culture and identify

Staphylococcus aureus, Staphylococcus epidermis, and Staphylococcus saprophyticus

Types of staphylococci we need to know

+

Staphylococcus aureus is coagulase +/-

Skin, eye, upper respiratory tract, urethra, and vagina

Where is Staphylococcus aureus typically present?

Breaks in the skin/mucosal barrier

When does Staphylococcus aureus typically cause disease?

surgical procedures

Staphylococcus aureus can affect many sites, especially after...

antiphagocytic

The capsule of Staphylococcus aureus has _______________ properties

endotoxin-like

The cell-wall peptidoglycans of Staphylococcus aureus have ___________________ activity

superantigens

Toxins of Staphylococcus aureus are referred to as...

Exotoxin TSST-1 and enterotoxins A to E

What are the toxins of Staphylococcus aureus?

Toxic shock syndrome

What does exotoxin TSST-1 of Staph aureus cause?

Food poisoning

What do enterotoxins A to E of Staph aureus cause?

Destroy tissue and cause purulent change

What do the enzymes of Staph aureus do?

Skin, bone, lungs, and heart

What are some common areas in which Staph aureus infections occur?

Methicillin-resistant Staphylococcus aureus (MRSA)

Specific type of Staph aureus that occurs in hospitals (nosocomial) and resistant to methicillin

Coagulase -

What type of Staphylococci are typically nonpathogenic?

Staph epidermidis and Staph saprophyticus

What types of Staph are coagulase negative?

With foreign bodies such as heart valves, joints, and shunts

When is Staphylococcus epidermis problematic?

Bacteriuria (high colony count in urine)

What can Staphylococcus saprophyticus cause?

Gram + ovoid/lancet found in pairs or chains

Identify the appearance and characteristics of streptococci (Gram reaction, shape of cells, and arrangement of cells)

facultatively; obligate; anaerobic

Streptococci are _____________ or _______________ aerobic/anaerobic

By ability to hemolyze blood agar

How are Streptococci separated?

Beta hemolytic, alpha hemolytic, and gamma hemolytic

What are the three categories of Streptococci?

Beta hemolytic

Streptococci that completely hemolyze blood agar

Serologically by carbohydrates into Lancefield types

How are beta hemolytic Streptococci separated?

Alpha hemolytic

Streptococci that partially hemolyze blood agar

Gamma hemolytic

Streptococci that are nonhemolytic

Streptococcus pyogenes and Streptococcus agalactiae

What are the beta hemolytic streptococci?

A

Streptococcus pyogenes is referred to as Group _______ strep

B

Streptococcus agalactiae is referred to as Group _________ strep

Streptococcus pneumoniae

What is a alpha hemolytic Streptococcus we need to know?

Pneumonia and meningitis

What does Streptococcus pneumoniae cause?

Streptococcus viridans

Group of generally nonpathogenic streptococcus

A; G; bacteriophage

Streptococcus if divided into groups ___________-__________ serotypes by ________________

Pharyngitis, necrotizing fasciitis, bacteremia, scarlet fever, and erysipelas

What does Group A strep (Streptococcus pyogenes) cause?

M protein

What does the cell wall of Group A strep (Streptococcus pyogenes) produce?

antiphagocytic

M protein produced by group A strep (Streptococcus pyogenes) is...

Rheumatic fever

What is likely an autoimmune phenomenon that occurs to M protein that cross reacts with cardiac myosin?

Up to 20

How many extracellular agents does group A strep (Streptococcus pyogenes) produce?

Streptolysin O, streptolysin S, streptokinase, hyaluronidase, and DNase

What are some extracellular agents Streptococcus pyogenes (Group A strep) produces?

Subsurface hemolysis

What does streptolysin O cause?

Surface hemolysis

What does streptolysin S cause?

fibrinolytic

Streptokinase is...

Neonates

What does group B streptococcus typically infect?

Group C and G

What groups of strep can cause infections similar to Group A?

Endocarditis, bacteremia (rarely), and dental caries

What can Streptococcus viridans cause?

Corynebacterium or diphtheroids, Listeria, Gardnerella, and Bacillus

What bacteria are gram positive bacilli (rods)?

curved; nonparallel

Corynebacterium or diphtheroids are slightly ___________ rods with _____________ sides

Skin and mucous membranes

Where are Corynebacterium or diphtheroids typically found?

pathogenic

Corynebacterium or diphtheroids are rarely pathogenic/nonpathogenic in humans

It's diphtheria, it's recovered from a sterile site, or isolated from multiple sites

Under what circumstances are Corynebacterium or diphtheroids pathogenic?

spore; aerobe

Bacillus is a ___________ forming aerobe/anaerobe

nonpathogenic

Bacillus are mostly pathogenic/nonpathogenic

Bacteremia due to indwelling catheter

What can bacillus cause?

Bacillus anthracis

Bacillus that is pathogenic and causes anthrax

Bacillus cereus

What bacillus causes enteritis?

Nocardia and actinomyces

What bacteria are filamentous and gram +?

immunocompromised

Filamentous gram positive bacteria, such as nocardia and actinomyces, are found everywhere and cause disease in _______________ individuals

gram negative rods

Enterobacteriaceae are... (Gram reaction, shape of cells, and arrangement of cells)

Escherichia, Enterobacter, Klebsiella, Proteus, Salmonella, Providencia, Shigella, and Yersinia

What bacteria are included in the Enterobacteriaceae group?

Vegetation, soil, and intestinal tract

Where are gram negative rods (Enterobacteriaceae) typically found?

Endotoxin

Toxin found in the cells walls of gram negative bacteria and some gram positive bacteria

lipids, polysaccharides, and some amino acids

Endotoxins consist of...

Classic and alternate complement cascades

What do endotoxins activate?

Fever, chills, hypotension, increased WBC, and low PLTs

What are some typical symptoms experienced due to exposure to endotoxins?

shock

Endotoxins in severe cases can cause...

gram negative bacillus

Pseudomonas is a... (Gram reaction, shape of cells, and arrangement of cells)

Moist environments such as shoes and hot tubs

What does Pseudomonas inhabit?

Burns, trauma, surgical wounds, and cystic fibrosis patients

Where are Pseudomonas infections common in the hospital?

Slime like polysaccharide, endotoxin, and proteases

What does Pseudomonas produce?

Inhibit inflammatory response

What do Pseudomonas secretions do?

Gram negative coccus arranged in pairs

Neisseria is a... (Gram reaction, shape of cells, and arrangement of cells)

Gonorrhea and meningitis

What diseases does Neisseria cause?

fastidious; special culture techniques

Neisseria are __________ and ________________ may be indicated

sensitivity to oxygen

Anaerobes have varying degrees of...

Clostridium tetani, C. botulinum, C. difficile, C. perfringens, and in abscesses

What are some common anaerobes?

tetanus; neurotoxin

Clostridium tetani is an anaerobe that causes ___________ and releases a _______________

botulism; neurotoxin

Clostridium botulinum is an anaerobe that causes ___________ and releases a _________________

pseudomembranous colitis

Clostridium difficile causes...

gas gangrene

Clostridium perfringens causes...