Microbiology Lecture Test 3

• 1. Family Streptococcaceae
• 2. Family Micrococcaceae

• Family Streptococcaceae
• 1. genus Enterococcus
• 2. genus Streptococcus

• Family Micrococcaceae:
• 1. genus Staphylococcus
• 2. genus Micrococcus

differentiates between 1. Micrococcae and 2. Streptococcacea

• 1. Micrococcaceae= catalase (+)
• 2. Streptococcacea= catalase (-)

• Staphylococci contain the enzyme catalase which converts H₂O₂ (hydrogen peroxide) into water and oxygen.
• The test is performed by emulsifying a colony of staphylococcus in H₂O₂ and observing a bubbling reaction as O is liberated.
• 

• 1. Gamma (y) hemolysis- no hemolysis
• 2. Alpha hemolysis -zone  of green - partial lysis of RBC's
• 3. Beta hemolyisis- clear zone of hemolysis - complete lysis of RBC's

• Gram (+)
• cocci
• clusters

• mainly inhabitants of the skin, skin glands, and mucous membranes
• generally opportunistic pathogens that enter through skin ruptures
• 31-40 diff species
• 6-7 are clinically significant, the rest are found mainly in animals

• 1. Staphylococcus aureus (most serious pathogen)
• The Coagulase (-)
• 2. Staphylococcus epidermidis
• 3. Staphylococcus capitis
• 4. Staphylococcus hominis
• 5. Staphylococcus saprophyticus

• Size: M-L
• Color: buttery white to creamy to golden
• w/some strains being B-hemolytic
• facultative anaerobes
• extremely resistant to adverse environmental conditions: pH, temp, drying, and many disinfectants
• Virulent Factors Enzymes and toxins:
• 1. Coagulases (triggers clotting of plasma)
• 2. Staphylokinase (fibrinolysin) - dissolves fibrin clots
• 3. Lipases
• 4. Hyaluronidases
• 5. Deoxyribonucleases
• Toxins:
• 1. Cytolytic toxins (1. Hemolysins 2. Leukocidins)
• 2. Enterotoxins -A, B, C, C₂, D, E, and F
• 3. Exfoliative toxin (epidermolytic toxin) and Toxic Shock Syndrome toxin (TSST)
• Staphylococcus aureus is present in most environments, colonization of some infants begins hrs after birth
• carriage rate in normal healthy adults ranges from 20%-60% mostly in the anterior nares (will be present in the on the skin and mucous membranes)
• main predisposing factors include: tissue injury, preexisting primary infections, diabetes mellitus, poor hygiene
• Methicillin Resistant (MRSA)
• emerged in mid 80's as 1 of the so called "superbugs"
• multi-resistant organism that poses an epidemiological problem in the hospital setting (nosocomial infections)
• 10-15% of population are carries
• 95% of strains of S. aureus have acquired genes for penicillinase
• Strains of MRSA carry multiple resistance to antimicrobials including methicillin, gentamicacin, cephalosporins, tetracycline, erythromycin, and even quinolones
• few strains have acquired resistance to all major drug groups except Vancomyosins
• Scope of clinical Staphylococcal disease:
• 1. Localized cutaneous infections (superficial skin infections)
• a.Boils or furuncles
• b. Carbuncles
• 2. Post-operative wound infections
• 3. UTI's
• 4. Bacteremia, meningitis, osteomyelitis
• Staphylococcal infections
• inhabit nasopharynx, they can be aspirated into the lungs and cause a pneumonia involving multiple abcesses and symptoms of fever, pain, and bloody sputum
• circulating bacteria can be transported to the liver, kidney and spleen and form abscesses
• Toxigenic Staphylococcal disease
• 1. Food Poisoning- caused by strains that produce enterotoxins A, B, and D in improperly refrigerated food (mayonnaise. processed meats, sauces, ham, chicken)
• 2. Scalded Skin Syndrome (SSS) or Ritter's disease- caused by strains that produce the exofoliative or epidermolytic toxin
• 3. Toxic Shock Syndrome (TSS)
• associated w/high fever, rash, vomiting, and sometimes death
• caused by strains that producce the toxin TSST-1 also known as enterotoxin F
• originally associated w/tampon use
• (sunburn-like rash, fascitis necroticans- extreme infection of skin and deeper parts, influenza-like rash, signs of soft tissue infection, coma, multiogan failure,

• 
• 
• 

• established in the metaphysis of a variety of bones (femur, tibia, ankle, wrist)
• abcess formation in the infected area result in a tender lump causing bone breakage
• symptoms: fever, pain, chills, and muscle spasms

• read manufacture's instructions about the use of tampons
• compare absorbency from brand to brand
• be familiar with the terms "junior", "regular", "super", and "super plus"
• wear only during the day
• replace 4-6hrs
• wash hands before inserting

• Coagulase is a plasma clotting enzyme secreted by Staphylococcus aureus- allows for clot formation
• 1. (+) Staphylococcus aureus
• 2. (-) Staphylococcus epidermis or S. saprophyticus

• generally part of the normal flora of the skin and mucous membranes
• mainly associated w/nosocomial infections such as catheter site infections, shunts, incision site infections, and nosocomial UTI"s
• associated w/ UTI's in elderly
• Characteristics of S. epidermidis:
• resembles S. aureus in microscopic and colonial morphology
• Coagulase (-)
• Novobiocin- sensitive

• generally produces white to extremely white colonies
• microscopic morphology resembles S. aureus
• it is mainly part of the normal skin flora
• Clinical Significance:
• mainly associated w/UTI's that involve the bladder and (or) the kidneys in young sexually active women or in adolescent girls
• Coagulase (-)
• key biochem test is that it is resistant to Novobiocin disc
• 

• penicillin susceptible strains (about 5%) are treated w/penicillin
• majority strain of S. aureus lactamase which allows them to breakdown penicillin
• susceptibility studies are recommended due to the variability in susceptibility patterns of penicillin resistant strains
• Drainage of abscesses should be performed for successful therapy
• 40% of nosocomial S. aureus infections are caused by MRSA
• new threat is an increasing number of Vancomycin resistant S. aureus

• 1. Streptococcus
• 2. Enterococcus

• 1. Streptococcus 2. Enterococcus
• gram (+)
• generally arranged in chains
• catalase (-)
• divided into categories based in the type of hemolysis they produce
• Classification and naming of Streptococci
• streptococci are classified and named following two systems:
• 1. Hemolytic pattern in conjunction with the Lancefield grouping
• 2. Scientific name from taxonomic organization
• Beta Hemolytic Streptococcus
• 1. Streptococcus pyogenes
• S. pyogenes is a strict parasite generally involved in upper respiratory tract infections
• Taxonomy-Beta Hemolytic
• these organisms can be further divided into a number of immunologic groups known as the Lancefield Groups (given alphabetic designations)
• Groups A, B, C, F, and G are commonly associated w/human infections
• Group A: Streptococci= S. pyogenes
• Group B Streptococci= S. agalactiae
• Virulence factors and toxins:
• 1. C carbohydrates- can also be teichoic acids found on surface of cell wall-protect from host cell's lysozyme defense
• 2. M-protein- resists phagocytosis and increases adherence
• 3. Capsule- chemically indistinguishable from HA capsules of host
• 4. Streptolysins- hemolysin that destroys that injures WBCS, liver, and heart tissue
• 5. Erythrogenic toxin- contributes to red rash and fever of scarlet fever
• 6. Streptokinase
• 7. Hyalyronidase
• Epidemiology and Pathogeneis:
• humans are the only significant reservoirs of S. pyogenes
• 5-15% of population are carriers
• outbreaks are seasonal, main pop. group affected is children 5-15yrs
• Main infections associated with S. pyogenes:
• skin infections: 1. Empetigo (associated w/poor hygiene, insect bites, and crowded living conditions)
• 2. Erysipelas
• 3. Cellulitis
• 4. Wound infections

• redness, edema, and swelling of pharyngeal membranes which results in difficulty in swallowing
• other fever, headache, nausea, and abdominal pain
• purulent discharge exudate may form over the tonsils and swollen lymph nodes
• tonsils may be white patch and contain white abscesses as well as pus

• 1. Pharyngitis- tonsillitis (strep throat)- often diagnosed by symptoms and direct antigen testing
• 2. Scarlet fever- caused by a strain capable of producing the pyrogenic toxin
• similar symptoms as in pharyngitis w/ addition of a skin rash and yellow to white coloration of tongue

• 1. Rheumatic fever (inflammatory condition of the joints, heart, and subcutaneous tissues)
• 2. Acute glomerulonephritis (AGN) (affects filtration of blood)
• 3. Streptococcal toxic shock syndrome
• 4. Streptococcal gangrene (necrotizing fascitis) also known as "flesh eating disease)
• note: necrotixing (dead) fascitis- connective tissue sheath around muscles and other organs

• Rheumatic fever (begin between 6 weeks after a strep infection)
• return fever after strep infection has finished
• pain, swelling and redness in joints
• shortness of breath
• unusual skin rashes
• unusually fast heart beat or heart damage

• develops between 3-6 weeks after the initial strep infection
• puffiness of face
• swelling of ankles
• headaches
• high blood pressure

• streptococcus are introduced into small abrasions or cuts, where they grow rapidly
• their enzymes digest connective tissue in skin, while their toxins poison the epidermal and dermal tissue
• rare, but potential for harm is high
• most aggressive infections have come from the Rocky Mountains and East
• Epidemiologists believe that these new strains are probably mutants that have acquired toxin genes from infecting viruses
• high incidence in 80's
• note that even the most virilant strains are not antibiotic resistant

• 1. Ear infections
• 2. Bacteremia and septicemia
• 3. Endocarditis
• 4. Meningitis

• size: Pinpoint-Small
• large zone of hemolysis
• key biochem reaction- sensitive (+) to bacitracin (A) disc
• Latex agglutination

• 1."A" disc- Bacitracin disc
• 2."P" disc- Optochin disc

• 1. Bacitracin discs ("A" disc)
• distinguishes Streptococcus pyogenes from Streptococcus agalactiae
• Streptococus agalactiae is resistant to it
• 
• 

• B-hemolytic Streptococcus group B
• normal flora in: GI tract, vaginal canal
• size: Pinpoint-Small convex
• very small zone of hemolysis
• key biochem reaction- positive CAMP test
• 

• In adults:
• UTI's, skin infections, bacteremia, endocarditis, osteomyelitis, post-partum infections (septicemia), urogenital (reproductive and urinary) infections in females
• In neonates:
• #1 agent implicated in pneumonia, bacteremia, meningitis

• may be involved in the same types of infections as groups A and B but with less frequency and generally in a milder form of the disease (NP infections, pneumonia, abscesses, meningitis)
• are not identified with one single biochemical test;
• identified by a Latex agglutination test 

• 1. Streptococcus viridans group
• 2. Streptococcus pneumoniae

• Streptococcus oralis
• Streptococcus mutans
• produce slime layers that are made of glucose polymers that adhere to tooth surfaces
• these sticky polysaccharides are the basis for plaque, the adhesive white material that comes from coinfected with other bacteria and fosters dental disease

• alpha hemolytic
• group of at least 5 species of gram(+) cocci that are Alpha-hemolytic resembling Streptococcus pneumoniae (Streptococcus mitans, S. mutans, S. Milleri, S. salivarius, S sanguis)
• part of normal flora of the oral cavity (gingiva, cheeks, tongue, saliva) as well as teh nasopharyx, genital tract, and skin
• occasionally involved in subacute endocarditis
• differential from Streptococcus pneumoniae by a negative (resistant) optochin "P" disc

range from fever, heart murmur, emboli, weight loss, anemia

• Alpha-hemolysis
• gram (+)
• lancet shaped
• Pinpoint
• "checker" appearance
• "P" disc-Optochin
• Most common infections caused:
• 1. Lobar Pneumonia, mainly caused by the encapsulated strain
• 2. Nasopharyngeal infections
• 3. Eye and ear infections
• 4. Occasionally meningitis on newborns or infants
• Symptoms of Pneumonia:
• chills, shaking, rapid breathing, fever
• severe pain in the chest wall, cyanosis, a cough that produces rusty colored blood sputum
• In children, can spread to the meninges and cause meningitis
• 

• "P" disc- Optochin disc
• identifies Streptococcus pneumoniae as it is sensitive to it
• 

• Non-hemolytic
• gram (+)
• cocci
• catalase (-)
• part of normal flora of GI tract and skin
• Opportunistic pathogens- mainly involved in UTI's and superficial skin infections and surgical wound infections

• 1. Enterococcus faecalis
• (in elderly patients undergoin surgery and affect the urinary tract, endocardium, wounds, blood, appendix, and other intestinal structures)
• is isolated w/much more frequency
• "superbug" VRE

• 2. Enterococcus faecium
• (large intestine)
• 3. Enterococcus durans
• (large intestine)
• ALL species are involved in the same infections, but E. faecalis is isolated w/much more frequency
• identified to species level by automated methods (Vitek, Microscan)
• Key biochem test: PYR (+)
• 
• 

• generally part of normal flora of skin, mucous membranes, or oral cavity
• generally non-pathogenic
• need to be differentiated from Enterococcus by PYR test
• Ex: S. bovis, S. equinus, and others
• source-animals

• 5 most significant strains in nosocomial infections are:
• 1. Methicillin resistant Staphylococcus aureus (MRSA)
• 2. Vancomycin resistant enterococcus (VRE)
• 3. Multidrug resistant Streptococcus pneumonia (MDRSP)
• 4. Vancomycin resistant Staphylococcus aureus (VRSA)
• 5. Methicillin resistant Staphylococcus epidermsi (MRSE)

• General Characteristics:
• gram (-)
• diplococci
• adjacent side flattened (coffee or kidney bean shape)
• capnophilic- requiring a CO₂ concentration between 3-10% 
• fastidious
• cold labile
• oxidase (+)
• fimbriae

• caused by Neisseria Gonorrhoeae
• symptoms:
• symptomatic, mild, severe
• appears: 2-5 days, moths, year
• Transmission: vaginal intercourse, anal intercourse, anal intercourse, oral sex, mother to child
• symptoms in men:
• prostatitis, periurethral abscesses, epididymitis, sterility
• Other complications: gonococcal conjunctivits, newborn and adylt: eye inflammation, discharge
• gonococcal pharyngitis, sore throat, fever, chills
• top 5 sexually transmitted diseases
• oropharyngeal and anorectal infections
• Specimen collection and processing:
• plated and incubated ASAP 
• collected on MTM based media that provide CO₂ environment such as JEMBEC plates
• Meningococcus
• found in nasopharynx of 3-15% asymptomatic individuals
• main strains associated with disease are: A, B, C, Y and W-135; with B being the most prevalent in the U.S. 
• main virulent factors include the capsule, fimbriae and endotoxin production

• inflammation of the meninges
• infections of the CSF
• infections and conditions associated w./Neisseria meningitis infects the mucous membranes of the nose and throat (nasopharyngeal), causing a sore throat
• Bacterial meningitis
• caused by 1of3 types of bacteria
• 1. Streptococcus pneumoniae (Pneumococcal)
• 2. Heaemophilus influenza (Hib meningitis)
• 3. Neisseria Meningitidis (Meningococcal)
• Neisseria Meningitidis
• come in 3 main or common strain called A, B, and C, and two rarer strains called Y and W-135
• each group can be recognized by molecules present in the capsule
• gram (-)
• diplococcus
• Infections and conditions associated w/ Neisseria meningitidis
• can cause meningitis can if the bacteria enters blood and cerebral spinal fluid where it can infect the protective covering (meninges) of the brain and spinal cord.
• Incubated: Chocolate Agar
• Marked by: fever, sore throat, headache, stiff neck, convulsions, and vomiting
• Symptoms:
• early symptoms are similar to flu
• In adults and children, the 1st are fever, vomiting, and drowsiness
• In infants:
• high-pitched moaning cry fever, perhaps cold hand and feet, difficult to wake up, dislike of being handled, vomiting, arching back
• Spread: sharing utensil, drinking containers, lipstick, cigarettes, kissing
• Aftereffects: balance problems, brain damage, deafness, epilepsy, recurring headaches, violent temper tantrums, amputations
• Prevention: vaccination, chemoprophilaxis, drinking containers, spoon, forks, knives, covering of mouth when sneezing or coughing, good hygiene

when pathogen spreads endotoxin into the generalized circulation, which is a potent white blood cells. Damage to the blood vessels caused by cytokines leads to vascular collapse, hemorrhage, and crops of legions called pertechiae

• 5. Meningoccemia can become a disease that has a sudden onset, marked by high fever, chills, delirium, and severe widespread ecchymoses
• 6. Generalized intravascular clotting, cardiac failure, damage to the adrenal glands, and death can occur within a few hours.
• Who is at risk?: newborns, children, young adults, elderly, AIDS patients, college students, and soldiers