comprehensive mixed deck - jonathan Flashcards
Let’s chat about botulism toxin… Is it resistant to heat? Is it resistant to stomach acid? How many types of toxins #? Which are the most common? How many subunits?
Heat labile Resistant to stomach acid 7 types of toxin (A to G) with A, B, and E being the most common two subunits to each toxin
T/F Neiseria are pathogenic in the mouth.
Neiseria have non-pathogenic and pathogenic strains which need to be distinguished for proper Tx N. meningitis can cause meningitis and can colonize the throat or the nasopharynx
What are normal flora of the skin?
Staphylococcus epidermidis S. aureus Diphtheroids (non-diphtheriae Corynebacteria) Anaerobes, such as proprionibacterium and peptococcus reside in the dermis. Also: proprionibacterium acnes
In what tissues do each reside? S. aureus S. epidermidis S. saprophyticus
What staph reside… Skin and nares Skin and mucus membranes Skin and GI tract
What are symptoms of S. saprophyticus UTI?
UTI with poluria and dysuria
Describe the Lancefield classification of streptococci.
Carbos extracted from the bacteria are subjected to precipitation tests with antisera. This places the beta-hemolytic groups into A through O. Note: group D is not beta-hemolytic
Explain the differences between Glomerulonephritis and Rheumatic Fever… Major symptoms? M-protein serotypes? Site of infection? Pathogenic mechanism?
1) G: edema, hypertension, hematuria. R: carditis, polyarthritis, subcutaneous nodules, skin lesions (erythema marginatum) 2) G: only a few types of M-protein. R: selected types of M-proteins but infection varies markedly by type 3) G: throat or skin, SKIN is more common. R: ONLY THROAT 4) G: deposition of immune complexes. R: antigenic mimicry between S. pyogenes and host tissue (heart, skin, and joints)
What is the pathogenesis and course of infection of infective endocarditis from Viridans Streptococci?
Alpha-hemolytic streptococci can infect through the mouth via oral trauma (including chewing) Causes transient bacteremia Bacteria can then bind to pre-existing lesion on heart valve Vegetation on valve Then has subacute course with intermittent bacteremia. Possibly fatal
What are the risks of a pregnant woman becoming infected with Listeria monocytogenes? Early term? Late term? Who is susceptible?
Bacteremia and transplacental infection Early term: abortion and still birth Late term: live births with risk of neonatal septicemia and meningitis Patients with cell-mediated immunosuppression are at risk
What can bacterial overgrowth in the small intestines cause?
Fat malabsorption B12 Deficiency bacteria belong in the large intestine, not the small intestine
When can bacteria grow in the upper small intestine?
Anatomical alterations (gastric bypass) can cause stasis and bacterial growth
What are Dx techniques do LABORATORIES use for Streptococcus?
1) G + chains 2) beta-hemolysis on blood agar 3) Sensitivity to Bacitracin indicates group A 4) Titer of >160 or a four-fold increase of Streptolysin O (ASO titer)
Bacteriology for Listeria monocytogenes… Gram status? Morphology? Hemolytic status? Motile? Temperature for growth?
G+ Rod Beta-hemolytic Motile with tumbling movement Grows well at cold temperatures, and creates risk for food contamination
Quick word on Wound-associated botulism… How is infection caused? What is Dx?
Spores in soil contaminate wound, germinate, and produce toxin Dx by wound culture or toxin in serum
Bonus question: Why… Metronidazole? Vancomycin? Fidaxomicin?
Metronidazole: anaerobic Vancomycin: G + multi-resistant enterococcus Fidoxomicin: a drug that stays in the intestines (doesn’t absorb into the blood) and is great for C. diff
What illnesses does Eikenella corrodens cause?
faculative gram - rod Skin and soft tissue infections associated with human bites and clenched-fist injuries (Like they said in kindergarden: No biting! My girlfriend does not listen to this)
Of the ALPHA GAMMA hemolytic, which strep is OPTOCHIN sensitive vs resistant?
alpha gamma optochin SENSITIVE S. pneumococci alpha gamma optochin RESISTANT Viridans streptococci
Compare Strep Pneumoniae with Viridians Strep in terms of Optochin Bile solubility
Strep pneumoniae is optochin SENSITIVE and bile SOLUBLE Viridians Strep is optochin RESISTANT and bile INSOLUBLE
Epidemiology for Anthrax (Bacillus anthracis)… Transmission?
Usually animal to animal. Humans are an accidental host.
Cutaneous anthrax… How does infection occur? What is its distinctive symptom? How serious is it?
Contamination of skin lesions by spores The lesion now produces a BLACK SCAB May lead to bacteremia The most common and least serious anthrax
How is differential Dx performed between botulism and Guilain-Barre syndrom?
Both are ascending paralysis illnesses that can be distinguished by patient history and laboratory toxin detection (serum, vomit, feces)
What are the byproducts of fast growing Clostridium perfringens?
H2 and CO2 gas
What is the Quelling reaction?
The Quellung reaction is a biochemical reaction in which antibodies bind to the bacterial capsule of Streptococcus pneumoniae, Klebsiella pneumoniae, Neisseria meningitidis, Haemophilus influenzae, and Salmonella. The antibody reaction allows these species to be visualized under a microscope. If the reaction is positive, the capsule becomes opaque and appears to enlarge.
Streptococcus Pneumoniae Gram status? Morphology? O2 status? Catalase? Oxidase? Optochin status? Bile solubility? Hemolytic status?
G + diplococci Faculative Anaerobe Catalase - Oxidase - Optochin SENSITIVE Bile SOLUBLE Alpha-hemolytic
What is the common clinical symptom caused by C. difficile?
antibiotic-associated diarrhea
What is the natural environment of Clostridium perfrinngens?
soil human GI vagina
Recap: What are the names of the anaerobic gram negative rods? Which is RESISTANT to penicillin?
Bacteroides fragilis Prevotella melaninogenicus Fusobacterium species B. fragilis is RESISTANT
What are the major and minor illnesses caused by Clostridium perfringens? What is the hallmark of infection?
1) GAS GANGRENE (histotoxinc clostridia) 2) food poisoning Hallmark: TISSUE NECROSIS Note: many species of Clostridium can cause gas gangrene. Clostridium perfringens is the most common. Gas production Gangrene from closed off blood vessels.
What is the prognosis of C. tetani infection?
60% fatality rate due to pulmonary complications and secondary infections This is why we get vaccinated
How is botulism prevented?
Cook all canned foods at 100 Celsius for 10 minutes
How is S. aureus strains determined during outbreaks? Doubtful we need to know the details
Serology Phage sensitivity/Phage typing DNA fingerprinting Ribotyping (rRNA) DNA of Protein A and Coagulase
What is the single most common bacteria in the stool? When can this cause injury?
Bacteroides fragilis Trauma or bowel rupture can cause intraabdominal infection produces anaerobic infection: foul smelling, gas producing, and necrotic
What are the gram stain, shape, and penicillin sensitivity of… 1) Fusobacterium 2) Prevotella 3) Anaerobic streptococci aka peptostreptococcus 4) Actinomyces
1) Cigar-shaped gram - rod, penicillin sensitive 2) gram - rod, penicillin sensitive 3) gram + cocci in chains, penicillin sensitive 4) Gram + branching rods, doesn’t say
Recap and Preview: What are the names of the anaerobic gram negative rods (3)? What are the names of the anaerobic gram positive rods (4)? What are the names of the anaerobic gram negative cocci (1)? What are the names of the anaerobic gram positive cocci (1)?
Anaerobic Gram - Rods: Bacteroides fragilis, Prevotella melaninogenicus, Fusobacterium species Anaerobic Gram + Rods: Corynebacterium, Lactobacillus, Actinomyces, Clostridia Anaerobic Gram - Cocci: Veillonella (quick note: commensal, not a pathogen) Anaerobic Gram + Cocci: Peptostreptococcus
What cultures should not be submitted for anaerobes?
Oral or fecal
what obligate anaerobes are found in intraabdominal abscesses (4)?
Bacteroides fragilis (resistant to penicillin) Fusobacterium Clostridium Peptostreptococcus
What is the mouth heart connection via Viridans streptococci?
Predominant microorganism in the mouth and are the most common cause of subacute endocarditis Note: they also make tooth plaque and hasten dental carries with lactic acid sugar fermentation
On growth mediums containing intact RBCs, explain the difference between… Gamma hemolysis Alpha hemolysis Beta hemolysis
1) no hemolysis 2) a cloudy green zone (RBCs are intact but the heme is green) 3) a clear zone with lysed RBCs Note: depending on the depth of hemolysis in the petri dish, the clear zone may not look completely clear
What is laboratory Dx for pneumococcal pneumonia?
Microscopic examination and culture of sputum Blood culture CSF culture
Aside from Clostridia botulism, what other bacteria is a common exotoxin food-borne diarrheal bacterial disease?
Staphylococcus aureus
Are food-poisoning enterotoxins secreted by S. aureus heat stable? To what temperature?
Heat stable. Resists boiling.
Explain how Gas Gangrene development is dependent on location.
Myositis is in muscle Fascitis is in fascia Cellulitis is is dermis and skin
What other illnesses must be considered in the differential Dx of botulism?
Myasthenia gravis (assymetrical) Guillain-Barre syndrome (assymetrical)
Explain the function of toxin A and B in C. difficile.
A binds to gut receptor B is cytotoxin that damages colonic mucosa and causes diarrhea (sometimes bloody) (B is a ADP-ribosylating Rho GTP binding protein
Epidemiology for Listeria monocytogenes… Where is it found? What foods are implicted?
Soil, water, and infected animals Dairy and meat
What obligate anaerobes are found in the Upper Respiratory Tract (4)? (oral or facial abscesses, sinusitis) (can spread to brain)
Prevotella Fusobacterium Peptostreptococcus Actinomyces (due to trauma)
What are the clinical syndromes of Streptococcus pneumoniae? What are the symptoms? Bacteremic? Fatal?
Pneumococcal pneumonia is the most frequent form of bacterial pneumonia Cough, fever, chills, pleuritic pain, RUSTY SPUTUM, leukocytosis 15% bacteremic 15% fatal if hospitalized Other syndromes include meningitis, otitis media, and sinusitis
What is Tx for Bacillus anthracis?
Ciprofloxacin Tetracycline Penicillin
Describe Fusobacterium species with regard to… Microscopic shape as a rod? Penicillin sensitive or resistant? Oxygen sensitive or resistant? Common sites of infections?
has tapered ends and are thinner than normal Gram - rods Penicillin SENSITIVE Oxygen SENSITIVE Oral infections, lung abscesses, pleuropulminary infections Note: some species are in GI infections, but says we don’t need to know these
What is lecithinase?
An alpha toxin that damages host cell membrane inclusing capillary and host erythrocytes
What is the pathogenesis of S. aureus as a toxin-mediating bacteria.
bacterial colonization (food, tampons, vasculature, skin) and production of the toxin. Toxin can affect areas anywhere in the body, not just at the site of colonization
With regard to morphology, how do you distinguish between 1) Streptococci Group A through O 2) Streptococcus pneumoniae (pneumococcus) 3) Neisseria (gonorrhea and meningiditis)
1) Chains of G+ 2) Diplococci with short dimension apposed 3) Diplococci with long dimension apposed
Page Q-11 is a quick review of the following as they relate to Colon health 2) Bifidobacterium 3) Lactobacili 4) Clostridia 5) Coliforms (E. coli) and Enterococcus 6) More than 400 other anaerobes 7) small amounts of aerobes, such as S. aureus, Pseudomonas, Proteus, Klebsiella
.
Explain the pathogenesis of Rheumatic Fever. On what tissue was the initial infection? How long after initial infection? What protein is involved? What tissues are involved?
Throat only. 2-3 weeks after strep infection M-PROTEINS activate antigens that attack SKIN, JOINTS, AND HEART Skin and joint problems subside. Heart problems may be ongoing
State invasive status and basic illness of the following: Clostridium botulism Clostridium tetani Clostridium difficile Clostridium perifringens Costridium septicum (don’t need to know) Clostridium ramosum (don’t need to know)
Clostridium botulism: noninvasive and causes botulism Clostridium tetani: generally noninvasive and causes tetanus (small invasive potential) Clostridium defficile: noninvasive and causes pseudomembranous enterocolitis Clostridium perifringens: very invasive and causes gangrene Costridium septicum: invasive in malignancy Clostridium ramosum: implies invasive in notes. Does not say.
Who is at highest risk for pneumococcal pneumonia?
Compromized HUMORAL immunity Spleenectomized patients pt with sickle cell anemia
What is the establishment of normal intestinal flora in newborns
Fetal intestine is sterile Breast fed babies have bifidobacterium Bottle fed babies have flora that resembles adults (they also are commonly overweight and have health troubles later in life)
What is impetigo?
Minor superficial skin infection of streptococcus
Normal flora in the genitorurinary tract?
Vagina: lactobacili Sometimes E. coli and Enterobacter is in the VJay 15-20% of women in childbearing age have Group B Streptococci in the Vjay. This can lead to sepsis in newborns.
What are five ANAEROBES that are common in the oral cavity?
1) Fusobacterium 2) Prevotella 3) Anaerobic streptococci aka peptostreptococcus 4) Actinomyces 5) others, such as anaerobic spirochetes
Yada Yada What are the clinical syndromes of food poisoning by S. aureus?
Nausea, vomiting, non-bloody diarrhea Note: these are specifically caused by the T-cell superantigen.
Corynebacterium… (this seemed deemphasized in the notes) What tissue does it normally inhabit? What test does it normally contaminate? What is it commonly called? Not a common infection, but there is one exception, which is?
Skin Contaminates blood samples Anaerobic diphtheroid Endocarditis in compromised patients
Which Staph is resistant to novobiocin?
S. saprophyticus
What is the pathogenesis of Clostridium perfringens with regard to food poisoning… (these seem like unecessary details) How many spores are required? Where is the enterotoxin found on the bacteria? What food is usually infected?
Needs lots of bacteria to cause infection (10^8) Enterotoxin is associated with the spore coat and the toxin is released into the intestine Usually found in meat
What are the clinical symptoms of botolulism toxin… Main symptom? Fever? Mental status? Sensory system? Affects on pharynx? Affects on eyes? Respiration?
Flaccid paralysis with bilateral symmetry in peripheral and cranial nerves No fever Normal mental status No sensory deficit Dysphagia and dry throat Diplopia (double vision) and diluted pupils May affect respiratory muscles
What is the gram stain and shape of Fusobacterium species?
Gram - rod
What is an EMG used for with botulism? Are the results conclusive?
electromyography tests diminished action potential of the peripheral nerves results are suggestive, not conclusive
What is the pathogenesis of Clostridium difficile?
Antibiotic-induced suppression of normal flora >> C. diff proliferates and produces two distinct toxins: exotoxin A and B
In Dx for Streptococcus, sensitivity to Bacitracin indicates what group?
Group A
page Q-3 has a chart of common anaerobic infection sites and their corresponding bacteria. It is not to be memorized.
page Q-3 has a chart of common anaerobic infection sites and their corresponding bacteria. It is not to be memorized.
What is Tx for Staphylococcus epidermidis?
1) remove implant 2) Vancomycin 3) possible combo with Rifampin and/or Gentamicin Interesting. Infection seems more mild, but we whip out the big guns for antibiotics.
What bacteria is the major cause of hospital bacteremias?
Staphylococcus aureus and Staph Epidermis
The use of antibiotics can cause what bacteria to overgrow?
Commonly, Salmonella and Shigella Also C. diff
What do you need to know about the bacteriology of S. epidermidis? Gram stain and other distinctive features…
Coagulase negative (S. epidermidis and S. saprophyticus only) Gram + Staphylococci with white colonies Catalase + (distinguishes staph from strep) Sensitive to NOVOBIOCIN
Quickly, what keeps the intestines in healthy flora?
Low oxygen Low pH Commensal bacteria produce synergistic products, such as vit K Commensal bacteria produce antibiotics that target harmful bacteria
What Dx techniques do physicians use?
A bead test that demonstrates linkage by strep chains pharyngeal swab is used
Intestinal anthrax… What food source? How common?
Ingestion of spores from meat. Rare.
Under what conditions do bacteria grow in the stomach?
Immediately after meals In the case of illness, such as Gastric Achlorhydia or Gastric Obstruction
Due to the severity of C. tetanus, there is a prophylaxis protocol if a person has a possibly infected wound. Wounds are either… 1) less than 6 hours old, clean, non-penetrating with neglible tissue damage 2) other wounds In each circumstance, what prophylactic Tx is required for… A) Pt with vaccine within 5 years? B) Pt with vaccine between 5 and 10 years? C) Pt with vaccine more than 10 years? D) Pt with unknown vaccine status?
A) 1 and 2: no Tx required B) 1 and 2: give one vaccine of inactivated toxiod C) 1: give one vaccine of inactivated toxiod. 2: one vaccine plus human tetanus Ig D) 1: three course vaccine. 2: three course vaccine plus human tetanus Ig Slide 30 has flow chart.
What faculative anaerobe is found in the dental area (1)?
Streptococcus viridans
What symptoms do the following toxins cause… 1) Botulism toxin? 2) Tetanus toxin? 3) Exotoxin A and B (Clostridium difficile)? 4) Alpha toxin (Clostridium perfringens)?
1) flaccid paralysis 2) tetanus (locked jaw) 3) diarrhea in pseudomembranous colitis 4) lecithinase which hosts cell membrane in combination with other degradative enzymes as the cause for “Gas Gangrene”
Of the non-spore forming anaerobes, what are the gram negative rods (name 4)?
Bacteroides (lower GI and female genital tracts. Abdominal infections) Fusobacterium (mixed infections. Oral and/or GI infections) Prevotella (oral infections) Poryphyromonas (oral and peridontal infections)
What is necrotizing fascitis?
“Flesh-eating bacteria disease” Invasive S. pyogenes Rapid infection Surgery may be required
What are the clinical symptoms of Clostridium perfringens food poisoning?
Abdominal cramps watery diarrhea for 8-22 hours resolves within 24 hours note: this is the 2nd or 3rd common cause of food poisoning
Detail: What is the recent emergent virulent strain?
27
fyi: Carbs not absorbed in the small intestine, feed the bacteria in the large intestine and keep the pH low
fyi: Carbs not absorbed in the small intestine, feed the bacteria in the large intestine and keep the pH low
What does botulism toxin do to nerves?
blocks acetylcholine release from nerve at neuromuscular junction details: the toxin is a protease that degrades the Ach vessicle docking proteins
Note: only 10% of bacteremias are caused by anaerobes. Which two anaerobes cause the most bacteremias?
Bacteroides fragilis Clostridium perfringens
What are the clincal syndromes of S. aureus S. epidermidis S. saprophyticus
1) toxin-mediated disease (food poisoning, TSS, and SSSS) and Invasive syndromes 2) Invasive syndrome commonly associated with foreign bodies 3) UTIs in young females attaches to uroepithelium via hemagluttanin
Streptococcus pneumoniae pathogenesis… Where are these bacteria resident? What causes infection? How does the bacteria deal with IgA? What is its lytic compound?
Resident in the oropharynx If aspirated plus cilia or phagocytosis is compromised, pneumonia can develop Protease to IgA Pnuemolysin
Explain how Bacteroides produce ammonia.
The metabolic activity of theses bacteria generates ammonia, acid, and gas in the colon. Ammonia is formed by splitting urea and from proteins.
Which have resistance to NOVOBIOCIN? S. aureus S. epidermidis S. saprophyticus
sensitive sensitive RESISTANT
Pathogenesis… Is C. botulism invasive? What tissue is ultimately affected? How does the toxin travel to that tissue?
C. botulism is not invasive. Affects nerves: flaccid paralysis (flaccid descending paralysis. Starts with the head and goes down. If hits respiratory muscles, you’re dead.) The botulism toxin is absorbed in the intestine, carried through blood to nerves. The toxin binds to a receptor on the nerve an is taken up by the nerve.
What is Erysipelas?
Severe cellulitis of the dermis and underlying tissues by streptococcus
What are the lysogenic toxins and enzymes that are produced by Clostridium perfringens?
Lecithinase: an alpha toxin that damages host cell membrane (including capillary and host erythrocytes) Collagenase: degrades ECM Hyaluronidase: degrades ECM
What pharyngeal and respiratory complications can occur with C. tetani?
respiratory failure possible aspiration, dysphagia, and oral pharyngeal involvement complications may be pulmonary infections and respiratory problems
Detail: What strain of S. aureus contain exfoliatins A and B?
phage group I
T/F Staph aureus is pathogenic because it is an INVASIVE disease, rather than an exotoxin producing bacteria.
False. S. aureus produces toxin-mediated diseases and invasive diseases.
What color are the colonies for S. aureus, S. epidermis, and S. saprophyticus?
S. aureus is yellow S. epidermis and S. saprophyticus is white
What neurotransmitters does tetanus toxin affect?
inhibits the release of glycine and GABA resulting in spastic paralysis and convulsive contractions aka locked jaw
What faculative anaerobes or aerobes are found in OB/GYN?
E. coli Klebsiella Proteus Streptococcus group B Staphylococcus
Knowledge of local flora aids in Dx and Tx. For example: Compare oral infections vs intraabdominal infections in their gram stain, shape, and penicillin senstitivity vs resistance
Oral infections: Gram + cocci and Gram - rods, penicillin senstitive Intraabdominal infections: Gram - rods, penicillin resistant
What are M proteins in streptococci?
M-proteins extend from the bacterial membrane through the capsule and into the extracellular membrane They aid in adhesion and antiphagocytosis They are antigenic and are a possible target for the immune system
Are acapsular streptococci pathogenic?
No
What is Px for S. aureus S. epidermidis S. saprophyticus
1) Handwashing and isolation 2) Handwashing 3) Not listed
What is the Tx for C. diff?
Stop offending antibiotics (usually ampicillin, cephalosporins, or clindamycin Treat with Metronidazole, Vancomycin, or Fidaxomicin Fecal transplantation
What is the gram status and linking of Group A Strep. pyogenes Group B Strep. agalactiae Group D Enterococcus Viridans Streptococci S. pneumoniae aka pnuemococci
All G+ in chains, except S. pneumoniae pnuemococci is LANCET shaped DIPLOCOCCI
Inhalation anthrax… How does infection occur? What demographic is most at risk of exposure? What are the steps of infection? How serious is it?
Inhalation of spores In undeveloped nations, people who work with wool and animal hides Spores >> phagocytized by macrophages >> germinate in lymph nodes >> medialstinal lymph enlargement Rapidly fatal
What obligate anaerobes cause bacteremia (4)?
Bacteroides fragilis Clostridium Fusobacterium Peptostreptococcus
What is the gram stain and shape of… Viridans streptococci Neisseria species Diphtheroids aka Corynebacterium species not including C. diphtheriae Staphylococci epidermidis Eikenella corrodens
Viridans streptococci: Gram + cocci Neisseria species: Gram - diplococci Diphtheroids aka Corynebacterium species: Gram + rods pleomorhic Staphylococci epidermidis: Gram + cocci in grape like clusters Eikenella corrodens: faculative Gram - rod
What are SpeA, SpeB, and SpeC? What are the two illnesses that they cause?
Protease pyrogenic exotoxins SCARLET FEVER (origin oropharyngeal streptococci) STREPTOCOCCAL TOXIC SHOCK SYNDROME
Viridans Streptococci… What type of hemolysis? What are the most common species? What tissues do they normally inhabit?
Alpha hemolysis Streptococcus mutans and Streptococcus sanguis mouth, nose, and pharynx
What are the subunits of the tetanus toxin? What do each do?
Subunits A and B B subunit binds to neuronal ganglioside A subunit has neurotoxin activity
What is the disease associated with… C. tetanus C. botulism C. difficile C. perfringens
C. tetanus: Tetanus syndrome. Generalized FLEXOR muscle spasm. No fever. No sensory loss. C. botulism: Botulism. Flaccid paralysis. Can involve cranial nerves. No sensory deficit. Usu clinical Dx. C. difficile: Pseudomembranous colitis. Diarrhea with yello-white plaque on colonoscopy. C. perfringens: Gas gangrene. Gas byproducts of anaerobic metabolism and tissue necrosis due to tissue swelling and blood vessel compression.
Of the non-spore forming anaerobes, what are the gram negative Cocci (1)?
Veillonella (not pathogenic)
Why is treatment of ALL streptococcus infection important?
We haven’t nailed down which M-protein varieties produce Rheumatic fever, therefore we should treat all streptococcus infections with penicillin
Of the non-spore forming anaerobes, what are the gram positive rods (name 4. only 2 are important) ?
ACTINOMYCES (oral and GI tract. Pathogenic) PROPIONIBACTERIUM (skin acne) Bifidobacterium (large intestine. Rarely pathogenic) Lactobacillus (large intestine. Not pathogenic)
Explain the pathogenesis of Acute Glomerulonephritis. On what tissue was the initial infection? How long after initial infection? What proteins from what subgroup of streptococci? What are symptoms? What is mechanism?
throat or skin. Skin is more common. 1 week after infection select M-proteins of Group A beta-hemolytic streptococci hematuria and edema deposition of immune complexes
Quick note: Strep Group C and D cause beta-hemolysis and are bacitracin resistant. They cause various infections.
.
What are the qualities of Tetracycline? Bacteria used on? Cidal or static? Mechanism?
Broad spectrum, especially used for intracellular bacteria (mycoplasm, rickettsia, chlamydia, bacillus anthracis) Static Protein inhibitor Prevents t-RNA from binding to 30s subunit
What is Tx for Streptococcus?
PENICILLIN Resistance has never been a problem
What are the groups of streptococci and what is the basis of distinguishing them?
A, B, C, D, and nontypable Carbohydrate antigens A and B are distinguished from other groups based on their patterns of hemolysis
What is the Tx for S. aureus abscesses… Name 1 physical treatment Name 3-4 antibiotics Name antibiotic combo for tolerant S. aureus
Abscesses need to be drained Semisynthetic penicillin: Dicloxacillin (oral) or Oxacillin (IV) Vancomycin is a last resort (methicillin resistance) Combo with Rifampin and/or Gentamicin
Flow chart of tests to perform if you suspect anaerobic infection…
1) Metronidazole senstive 2) Gram stain 3) + do microscopy and Nagler reaction, lactose egg yolk agar, gas liquie chromatography of fatty acid in culture of supernatants of bacteria 3) - suspect Bacteriodes, then do gas liquie chromatography of fatty acid in culture of supernatants of bacteria
What is the protocol for sampling anaerobes?
Send samples to lab ASAP Use a container with thioglycolate, an oxygen-reducing agent Inject specimen into specialized anaerobic container or in a capped syringe with no air Use a Gaspak jar: NaBH4 + NaHCO3 plus H2O produces H2O and CO2
Detail: S. epidermidis and … blood agar? Mannitol?
Little hemolysis on blood agar Does NOT ferment mannitol
What are the qualities of Penicillin? Bacteria used on? Cidal or static? Mechanism?
Most G- and G+ G- enterics Cidal Cell wall synthesis inhibitors Prevents transpeptidase and peptidoglycan cross-linking
Are Streptococcus pyogenes found at site of damage in Glomerulonephritis or Rheumatic Fever?
Nope. Infection is immunologically mediated either with immune complexes or cross reactivity of antigen vs host mimicry
Why are anaerobes catalase negative?
O2 production in aerobic fermentation can become H2O2. Catalase breaks down H2O2 Anaerobes do not need this function Note: catalase is part of the membrane cytochromes.
What are the clincial syndromes associated with toxic shock syndrome TSS?
Fever, rash, desquamation of palms and soles. Hypotension and shock.
What is the immunization for C. tetani? What is the immunization and booster schedule and what the vaccine is called.
DPT vaccine (diphtheria, pertussis, tetanus) Three doses in first 6 months. Booster at year 1, prior school entry, and every 10 years. Inactivated toxiod vaccine
Staph aureus epidemiology… On what tissues is it normally found? What patients are more susceptible?
Skin, mucous membranes, and nose Diabetics, drug addicts, immunocompromised patients, and those with implanted devices.
What is the catalase status and oxidase status of… C. tetanus C. botulism C. difficile C. perfringens
All are catalase and oxidase negative
There is a diagram for classification of Streptococcus pyogenes on page S-2. What are the three tiers of tests for Streptococcus classification?
1) Alpha, Beta, Gamma 2) of the Betas, Test for C carbohydrates A through O 3) of the A carbohydrates, Test for M proteins 1 through 90
What antibiotics are used for intraabdominal infection?
NOT penicillin. Bacteroides is resistant to penicillin DO USE: Clindamycin, Cefoxitin, Metronidazole Also: aminoglycoside, such as Gentamicin is useful for treating the aerobic Gram - rods
What are the clinical syndromes of Staphylococcus… How does it compare in intensity with S. aureus? What should you suspect if the patient is symptom free but is blood positive for S. epidermidis?
Low grade fever, pain, and discomfort. Less severe than S. aureus If symptom negative, but blood positive, suspect skin flora contamination
What are the general characteristics of Clostridium? Aerobic or anaerobic? Gram status and shape? Spore status? Catalase status? Oxidase stauts?
Obligate anaerobe Gram positive rods Spore forming Catalase negative Oxidase negative
What is Tx for S. saprophyticus? Why are these the drugs of choice?
Trimethoprim sulfamethoxazol (Bactrim) Norfloxacin (quinolone) excellent penetration into urinary bladder.
What is prevention of early onset/vertical transmission infection of Group B streptococci neonatal infection?
Culture pregnant women’s VJ and treat intrapartum parenteral penicillin or ampicillin Intrapartum = during childbirth Parenteral = infusion via route other than mouth
What are laboratory tests for botulism toxin?
detect toxin in serum, vomit, feces, or suspected food
Actinomyces… this one is highlighted. Gram stain and shape? Oxygen sensitive or resistant? What tissue does it normally inhabit? What infections does it cause? What is the characteristic growth feature?
nonspore forming anaerobic gram + rod Oxygen TOLERANT Oral pharynx and GI tract Infections: cervical-facial (oral and dental) and abdominal with sinus tract Sulfur granules (yellow granules of microcolonies plus cellular debris) are characteristic along with a molar tooth appearance
Compare pneumovax to prevnar 13 with regard to… Recommended for what populations? T cell dependence or independence? Which prevents pnuemococcal meningitis?
Pneumovax is recommended for pt over 65 and people over 2 years old who are at risk for infection (sickle cell, spleenectomy, HIV, and immunocompromised patients). T cell independent and has low booster yeilds. Prevnar 13 is recommended as part of normal pediatric vaccination and prevents pneumococcal menigitis. T cell dependent
What faculative aerobes or aerobes are found in Liver Abscesses?
E. coli Klebsiella Proteus Enterobacter Pseudomonas Streptococcus group D Staphylococcus
How does S. aureus contribute to colonization of vasculature and/or skin? What is the tampon-related infection called?
Vasculature: S. aureus contains fibrinogen and fibrinogen receptors Skin: S. aureus contains exfoliatins that bind to damaged skin (wound sites) Tampon: Toxic Shock Syndrome toxin
Why are antibiotics not always helpful with S. aureus toxin-mediated diseases?
Immunological effects due to the superantigen are already in effect before symptoms develop.
How would you Dx Clostridium tetani due to its spore location?
C. tetani have only one “terminal spore” that looks like a tennis racket. See slide 6 and 9 on Clostridia I ppt. All other species have subterminal spores.
List the many positive tests for S. aureus that are not positive for S. epidermis and S. saprophyticus.
Coagulase Mannitol DNase hymolysis Protein A Phage receptor
What are five normal AEROBIC/ FACULATIVE bacteria in the oral cavity and saliva?
Viridans streptococci Neisseria species Diphtheroids aka Corynebacterium species not including C. diphtheriae (these are usually not pathogenic) Staphylococci epidermidis Eikenella corrodens
What are the two major mechanisms that cause illness with Clostridia? What are examples of each?
Exotoxin-mediated disease: Botulism-toxin Invasion and inflammation: tissue invasion and damage due to host’s immune system
Why are there few bacteria (<10^5) in the upper small intestine?
Bile acids are antibiotic Peristalsis moves bacteria down the GI tract
Which have surface protein A S. aureus S. epidermidis S. saprophyticus
S. aureus has surface protein A
What is Tx for S. aureus S. epidermidis S. saprophyticus
1) MSSA - beta lactams and/or MRSA -vancomycin, daptomycin, linezolid, ceftaroline 2) Vancomycin (reistant to beta-lactams) 3) Bactrim
What are the Dx tools for anaerobic bacteria?
Gram stain, morphology, spores, and production of unusual fatty acids (analyzed by gas chromatography)
Of the non-spore forming anaerobes, what are the gram positive cocci (name 2. only one is important)?
PEPTOSTREPTOCOCCUS (oral, GI, and vaginal tracts. Mixed infections) chains Peptococcus (skin and GU tracts. Mixed infections) clusters
What is the medium for culturing anaerobes?
Thioglycollate broth
What is the Tx for Gas Gangrene Clostridium perfringens?
SURGICAL wound debridement penicilin (G+) to kill remaining bacteria hyperbaric oxygen
What are the benefits of normal intestinal flora?
Interfere with colonization of pathogens Produce Vitamin K and B 12
What obligate aerobes are found in OB/GYN pelvic or ovarian abscesses?
B. fragilis Prevotella Fusobacterium Peptostreptococcus
As an invasive bacteria, what is the method of adhesion and invasion?
Lots of adhesive molecules that bind to host membranes (fibrinogen, fibronectin, collagen, platelets) Bind to membranes, colonize, secrete toxins, and evade host defenses.
What are the toxins associated with… How is Dx completed… C. tetanus C. botulism C. difficile C. perfringens
C. tetanus: Tetanus toxin leading to SPASTIC paralysis. Clinical Dx C. botulism: botulism toxin leading to FLACCID paralysis. Detect toxin for Dx. Usually clinical Dx. C. difficile: Extoxins A and B leading to damaged colonic cells. Detect toxin for Dx C. perfringens: multiple toxins and proteases for tissue destruction and invasion (lecithinase, collagenase, etc…). double zone of hemoylsis on BAP
What is the role of normal aerobic oral cavity flora in disease (3)?
1) if normal flora are eliminated by antibiotics, they may be replaced by drug resistant Gram - rods or yeast 2) Small percentage of normal through flora are still pathogenic (eg. Pneumococcus and S. aureus 3) Aerobic Gram - rods (eg. E. coli or Klebsiella) can colonize the oral cavity (this number was highlighted in the notes)
What are the virulence factors of Bacteroides fragilis? With what co-infection is Bacteroides fragilis more severe?
Capsule More severe with E. coli co-infection
What are the notable toxins and enzymes through which S. aureus causes damage.
1) Alpha toxin: lyses host cell membrans 2) Coagulase: forms clot in human plasma These were also mentioned… Leukocidins: lyse leukocytes Proteases Staphylokinase: lysis of blood clot or fibrin Hyaluronidase: disovles hyaluronic acid Lipase: dissolves lipids and lipoproteins
Describe Bacteriodes fragilis with regard to… Relationship to bile? Tolerance of Oxygen? Penicilin (Important!)? Under what circumstances it is a common infection?
Resists bile May tolerate some oxygen during growth PENICILLIN RESISTANT intraabdominal rupture and female genital infections
What faculative anaerobe or anaerobe are found in the Pulmonary area (2)?
Streptococcus Staphylococcus (nosocomial) Enterobactereaceae
What is the “protective antigen” of anthrax?
A protein that facilitates entry of exotoxins into host cells. An antibody to this protein is protective
What patient population does S. aureus SSSS usually affect? What are the symptoms
infants. Erythematous skin followed by exfoliation
On what tissues are Strep found Group A Strep. pyogenes Group B Strep. agalactiae Group D Enterococcus Viridans Streptococci S. pneumoniae aka pnuemococci
1) skin and oral pharynx 2) vagina and colon 3) colon 4) oral 5) oral pharynx
What is the Tx for Group A Strep. pyogenes Group B Strep. agalactiae Group D Enterococcus Viridans Streptococci S. pneumoniae aka pnuemococci
1) Penicilin 2) Penicilin or Ampicilin 3) RESISTANT, sometimes even to vancomycin 4) Penicilin 5) RESISTANT sometimes to penicilin and erythromycin
What are prevention practices for Listeria monocytogenes?
Pregnant women and immunosuppressed patients should avoid raw milk and unprocessed soft cheese
Bacteriology of Bacillus anthracis… Gram status? Spore? O2 status?
G + rod, spore forming, aerobic
What is the Tx for C. tetani (list 5 treatments including 2 antibiotics)?
human tetanus Ig penicillin plus wound debridement (penicillin is used for Gram +) metronidazole is used if there is a penicillin allergy respiratory support if necessary immunization with tetanus toxiod to prevent recurrence
What is prophylaxis for C. diff?
PRUDENT USE OF ANTIBIOTICS isolation in case of outbreak and more consistent hand-washing
What are the three toxin-mediated diseases caused by S. aureus? What are the toxins in general? For which is colonization necessary?
1) Food poisoning (by enterotoxin some are superantigens) colonization is NOT required. Toxin can cause illness. 2) Toxic Shock Syndrome (TSS) (TSST-1 supersuperantigen) Colonization REQUIRED 3) Staphylococcal Scalded Skin Syndrome (SSSS) by exfoliatins A and B. Infection site does not have to be the site of toxin action
What are the lab Dx features that S. aureus, S. epidermis, and S. saprophyticus share?
All… G+ grape clusters Catalase Faculative anaerobes, although S. saprophyticus is slow anaerobic growth Teichoic acid
What is the gram stain and shape of Prevotella melaninogenicus?
Anaerobic gram - rod
What is the general epidemiology of C. tetanus… Where is its natural habitat? How common is it in the U.S. vs other countries? How does infection occur?
Natural habitat is in the soil Rare in the U.S. due to immunization and common in developing nations (eg infected umbilical stump) Cases occur due to puncture wounds (a random nail with that contains soil bacteria) where spores germinate in the deep and dirty wound under anaerobic conditions
What are invasive syndromes associated with streptococcus (6)?
1) puerperal fever 2) Acute pharyngitis and tonsilitis 3) Impetigo 4) Erysipelas 5) Necrotizing fascitis 6) a bunch of other illnesses covered next year
What are the most common contaminants in blood cultures?
Diphtheroids and S. epidermidis colonize the skin and can infect blood when drawn.
What explains why C. diff is so low in the general population and so high in hospital patients?
Probably fecal oral transmission from hospital personel
What are the qualities of Ciprofloxacin… Bacteria used on? Cidal or static? Mechanism?
Cidal G- often used for G- enteric bacilli DNA replication inhibitor Inhibits DNA gyrase
What bacteria are normally found in the lower trachea?
Trick question! None.
Group B streptococci… What two patterns of infection occur? What is mode of transmission for each? Which has more severe health risks?
Early onset within 1 week caused by vertical transmission from mother to newborn is more severe Later onset is caused by infant-to-infant spread with a less fulminant course and lower mortality Fulminant = quickly
What is the source of infection for… C. tetanus C. botulism C. difficile C. perfringens
C. tetanus: acquired from soil via puncture wounds C. botulism: oral ingestion of toxin mostly. Note toxin is heat labile. C. difficile: Antibiotic suppression of normal flora leading to bacterial overgrowth and toxin production. Often a consequence of antibiotic use. C. perfringens: Wound contamination with bacterial flora found in soil and GI tract
What is prevention for… C. tetanus C. botulism C. difficile C. perfringens
C. tetanus: immunization C. botulism: heat canned food to 100 degrees C C. difficile: judicious use of antibiotics and handwashing C. perfringens: good wound care
What Streptoococci is in Group A Group B Group D
What Groups are the following streptococcus in? S. pyogenes S. agalactiae Enterococcus
Describe Prevotella melaninogenicus with regard to… Where is common site of infection (1)? What is a specific disease called at the common site of infection? Penicilin sensitive or resistant? What is its distinctive feature when grown on blood agar?
Oral infections Periodontal disease Penicillin SENSITIVE Black pigment from hemin precursor necessary for growth
What is the Dx for C. diff?
History of antibiotic use Exotoxin B in stool samples ELISA to detect toxin Sigmoidoscopy with Pseudomembrane
What are the variants syndromes of… (note: not all have variants) C. tetanus C. botulism C. difficile C. perfringens
C. tetanus: no variants C. botulism: Infant botulism. Wound botulism. C. difficile: no variants C. perfringens: food poisoning due to enterotoxin of C. perfringen
As an exotoxin producing bacteria, do clostridia organisms need to be consumed to cause illness?
As an exotoxin, botulism can be secreted by clostridia into food. Only the exotoxin needs to be consumed to cause illness. No clostridia need to be consumed.
Pathogenesis of Staphylococcus epidermidis… Nothing exciting here. Just wing it.
colonizes prosthetics, produces biofilms, there is a carbohydrate that mediates biofilm poorly misunderstood
What are the qualities of Group B strepococci… Gram stain and growth phenotype? Hemolysin type? Bacitracin status? Hippurate status? What is the most important species?
G+ cocci in chains Beta hemolysin, but less hemolysis than Group A Bacitracin resistant Hydrolizes hippurate Streptococcus agalactiae is the most important species
What is the gram status, O2 status, and Catalase status of Streptococci?
Gram + found in chains Faculative anaerobe and aerotolerant Catalase negative
What are the three pathways for human infection by Anthrax? Note: all of these come from animals.
Cutaneous anthrax Inhalation anthrax Intestinal anthrax
What are prevention efforts against Bacillus anthracis? Who?
Vaccination Veterinarians and military if biological warfare is possible.
What is the most common anaerobic gram - rod?
Bacteroides fragilis
What is unique about the spore formation of clostridium for Dx purposes?
Location of the spore in the bacterium may aid in species identification (e.g. terminal spores = Clostridium tetani)
What Tx would you use for aspiration pneumonia? Is Dx of causative organism useful?
Penicillin Most of the aerobic and anaerobic oral cavity bacteria are penicillin sensitive No need to find causative agent. It is probably a mixture.
What is Listeriolysin O?
A cytolysin secreted by Listeria that allows it to escape a phagosome
Compare the aerobic status, gram stain, shape, and spore formation of… C. tetanus C. botulism C. difficile C. perfringens
All anaerobic Gram + rods C. tetanus has terminal spore (Dx) The rest have subterminal spore
What obligate anaerobes are found in the dental area (4)? (periodonititis, caries, abscess) (can spread to brain)
Prevotella melaninogenicus Peptostreptococcus Actinomyces Fusobacterium nucleatum
What are the two vaccines for pnuemococcus?
Pneumovax is a 23 valent polysaccharide vaccine Prevnar 13 is a conjugated vaccine conjugated to Diptheria proteins
Epidemiology of Staphylococcus saprophyticus What is normal tissue? What illness is it a common cause of?
skin commensal 2nd leading cause of UTI in women
What are common infections by enterococcus Group D strep?
UTI Wound infections Sepsis, especially in older patients
What are the proper steps to culture an anaerobe? What is the medium for culturing anaerobes? Which cultures should not be submitted for anaerobes?
Collect specimen with little exposure to air and inject into an anaerobic culture Look for gram staining (fusobacterium) or morphology (Prevotella) may be helpful Thioglycollate broth Oral or fecal should not be submitted for anaerobes
fyi: colon bacteria convert bilirubin to urobilin and sterobilin.
fyi: colon bacteria convert bilirubin to urobilin and sterobilin.
Does Clostridium perfringens a slow growing or fast growing organism?
Grows RAPIDLY in anaerobic environments usually requiring surgery to remove the infected tissues RAPIDLY FATAL if not treated
What faculative anaerobe or aerobe is found intraabdominal?
E. coli Klebsiella Proteus Pseudomonas Streptococcus group D
There is a huge list of invasive disease examples by S. aureus on page R-4 and R-5. There is only one example that is in bold. What is it?
Catheter site infections
What is Px for Group B Strep. agalactiae S. pneumoniae aka pnuemococci
2) Tx mother with penicilin before delivery 5) pneumococcal vaccines
General pathogenesis of Streptococcus… What are the lysogenic compounds? What are the antiphagocytic compounds? What are the proteases?
1) Streptolysins O and S, Streptokinase, DNAase 2) Hyaluronic acid capsule and M proteins 3) SpeA, SpeB, SpeC
What is the relationship between Bile and bacteria? Note: it is a two way street.
Bile is antibiotic. Overgrowth of bacteria can convert conjugated bile into free bile >> leads to fat malabsorbtion
What obligate anaerobes are found in Liver Abscesses?
Bacteroides Fusobacterium Clostridium Peptostreptococcus
Of the BETA hemolytic, which strep is BACITRACIN sensitive vs resistant?
beta and bacitricin SENSITIVE Group A S. pyogenes beta and bacitricin RESISTANT Group B S. agalactiae
What strep are hemolytic BETA ALPHA, BETA, GAMMA ALPHA GAMMA
BETA: Group A Strep Pyogenes and Group B Strep. agalactiae ALPHA, BETA, GAMMA: Enterococci ALPHA GAMMA: Viridans streptococci and S. pneumoniae Pneumococci
What is that all too famous inflammation caused by C. diff that we learned in pathology?
pseudomembrane formation
What major illness is caused by Viridans Streptococci?
INFECTIVE ENDOCARDITIS
Explain the gram stain and colony morphology of S. aureus S. epidermidis S. saprophyticus
In staphylococci, which species has G+ cocci in CLUSTERS, YELLOW colony G+ cocci in CLUSTERS, WHITE colony G+ cocci in CLUSTERS, color not specified
What are the differences between Streptolysin O and Streptolysin S in terms of oxygen stability and antigenicity.
O: oxygen labile and antigenic to antibody ASO S: oxygen stable and not antigenic
What are two important sequelae of S. pyogenes infections?
Rheumatic fever Acute glomerulonephritis
With regard to Bacertoides fragilis, Dx of infection, is this bacteria found below or above the diaphragm?
Bacteroides fragilis is penicillin resistant and found in infections below the diaphragm. This can be used to distinguish between upper GI tract vs lower GI tract and genital area infections.
Infant botulism… What ages are affected (age in months)? What is the common food source?
1-8 months Honey
What are the three toxin-mediated diseases caused by S. aureus?
1) Food poisoning 2) Toxic Shock Syndrome (TSS) 3) Staphylococcal Scalded Skin Syndrome (SSSS)
Note: S. aureus can be contained or become systemic. If it is systemic, it can affect any organ system.
Note: S. aureus can be contained or become systemic. If it is systemic, it can affect any organ system.
Are botulism spores heat labile? Is botulism toxin heat labile?
Spores are resistant to heat Toxin is heat labile therefore cook all canned foods
Lactobacillus… (this seemed deemphasized in the notes) What tissues does it normaly inhabit? What is the symbiotic function in our bodies? What common fermented food products use this bacteria?
GI flora and vagina Keeps the pH low Used in yogurt and sauerkraut
What is the pathogenesis of Listeria moncytogenes?
Invades mononuclear cells Grows intracellularly Moves from cell to cell by host actin filament Escapes form host phagosome into cytosol by secreting cytolysin (Listeriolysin O)
What are Tx for anaerobes (7)? This is total answer.
1) Penicillin, except for B. fragilis, thus for infections below the diaphragm, penicillin must be used in combination with other antibiotics 2) Clindamycin 3) Newer cephalosporins (cefoxitin) are effective against B. fragilis 4) Chloramphenicol (static) 5) Metronidazole 6) Aminoglycosides (aerobes) + Gentomycin + Cefoxitin or Clindamycin are used for mided aerobe-anaerobe 7) Surgical drainage (antibiotics cannot get to inside an abscess)
What is Tx for infant botulism?
Supportive treatment New antitoxin antibodies are being used
What is Puerperal Fever?
Infection of the uterus after childbirth Once was fatal, now is uncommon in developed countries
What obligate anaerobes are found in the pulmonary area (3)? (aspiration pneumonia, lung abscess)
Fusobacterium Prevotella melaninogenicus Peptostreptococcus
Bacteriology of Group D Streptococci (Enterococci)… What are the most important species? What are the hemolysis pattern? Growth in Salt status? Natural tissue habitat? Antibiotic resistance? Last resort antibiotic?
Enterococcus faecalis and Enterococcus faecium Hemolysis varies from strain to strain Can grow in high salt Common in GI tract Resistant to many antibiotics. Vancomycin is last resort, but resistance is a problem
THIS WAS IN THE NOTES, NOT SURE ABOUT WHY. What are the features of Neisseria… Hemolytic status? Optochocin status? Bile status? Quellung status? How does Viridians Streptococci compare on optochin and bile status?
Alpha hemolytic Optochin senstive (viridians strep are optochin-resistent) Bile solulbe (viridians are not soluble in bile) Quelling rxn used to determine capsule (over 90 different types)
What is the general pathogenesis of C. tetanus… Is C. tetanus an invasive and/or toxin-mediate disease? How many serotypes? What organ system does C. tetanus infect?
C. tetanus is a noninvasive, toxin-mediated disease with one serotype. Tetanus toxin is a neurotoxin that affects the CNS and PNS
What are the clinical syndromes associated with C. tetani… What is the incubation period? What is are the major muscle symptoms? Bonus question: which muscle groups? Is fever involved? Is sensory deficit involved? Note: we’ll mention respiration next…
Incubation period is 4 days to several weeks Main clinical feature is violent muscle spasm, predominently the FLEXOR muscles, plus clenched teeth, and neck and back arched (these are extensors) Symmetrical paralysis is unique to tetanus (along with strycnine) No fever No sensory deficit Respiratory complications…
Botulism symptoms broken down by system… GI/Urinary Neurologic Muscular
GI/Urinary: abdominal pain, intestinal ileus, urinary retention Neurologic: dry mouth, diplopia, dilated pupils, dysphagia, decreased gag reflex. NO sensory deficiency. Muscular: symmetrical muscle weakness. Respiratory muscle paralysis.
Epidemiology of Group B streptococci… What tissue does this group commonly inhabit? What major infection does Group B cause?
Vaginal and colonic flora 1/3 of all NEONATAL INFECTIONS: septicemia, meningitis, pneumonia, and death
Prevention of S. aureus (Just general stuff. Nothing noteworthy)
handwashing judicious use of antibiotics intranasal mupirocin, when necessary
What is Acute Pharyngitis and Tonsilitis? Why must this be Dx and Tx (ie, what is the progression of the disease if untreated)?
Strepthroat Dx and Tx with penicillin All strep strains must be treated because some strep strains can progress to RHEUMATIC FEVER
How are the symptoms of infant botulism different than adult botulism? What are the symptoms?
Symptoms are more subtle Constipation, weak head control (flaccid neck muscles), cranial nerve deficit
What types of infections are caused by Group A Strep. pyogenes Group B Strep. agalactiae Group D Enterococcus Viridans Streptococci S. pneumoniae aka pnuemococci
1) skin infections, pharyngitis, necrotizing fascitis, AGN, RHEUMATIC FEVER 2) neonatal sepsis and meningitis 3) UTI, sepsis and endocarditis, especially in the ederly and weak immune response 4) endocarditis 5) Otitis media (children), pneumonia, sepsis, meningitis (ederly)
What are the toxins that produce Staph Scalded Skin Syndrome? Are they in the main genome or a plasmid?
Exfoliatins A and B Plasmid
What is the aerobic status, invasion status, gram stain, and shape of Clostridium difficile?
anaerocbic, non-invasive gram + rod
What are the two drugs used for C. tetani and why?
Penicillin is used for Gram +. It is a cell wall inhibitor. Metronidazole is used if there is a penicillin allergy. It is a DNA replication inhibitor used for anaerobes.
What faculative anaerobe or anaerobe are found in the Upper Respiratory Tract (2)?
Streptococcus Staphylococcus
What distinguishes S. aureus “invasive disease” from an toxin-mediated disease in terms of localization and presentation.
Suppuration and abscess formation according to anatomic locations
What is the general epidemiology of C. botulism… Incidence level? Natural habitat vs clinically-relevant habitat? What is wound botulism? What is the source of infant botulism? (we discuss these latter two questions later in the deck)
Very low incidence Soil organism that is often found in canned foods and smoked fish. Botulism spores can germinate, grow, and produce botulism toxin in 2-3 days Wound botulism is rare. Spores germinate in a wound. Infant botulism is from honey. C. botulism grows anaerobically in the GI tract.
What are the methods that S. aureus uses to evade host defenses?
1) Protein A: binds the “wrong end” of IgG 2) enterotoxins A-E, G, H, I Protein A is a B-cell superantigen The enterotoxins are T-cell superantigens Also mentioned… Capsule is antiphagocytic Eap (Map) is a surface protein that impairs neutrophils
Peptostreptococcus… What is the gram stain and morphology? What tissues does it normally inhabit? Most anaerobes are in mixed cultures, in what tissues can peptostreptococcus found in pure cultures?
Gram + Cocci IN CHAINS. Resembles streptococci in morphology, but is an anaerobe Normal flora of mouth, urogenital, and GI tract Common infection Can be found in pure culture in pleuro-pulmonary infections, brain abscesses, and OB-GYN infections
How is Dx of infant botulism determined?
toxin or organism found in stool
Epidemiology of S. epidermidis… Colonizes on what tissue? How opportunistic? Adheres to what? Who is susceptible?
Normal skin flora Very oppotunistic that adheres to medical implants very efficiently Neonates, patients in renal failure, immunocompromised patients
Epidemiology of Streptococcus… On what tissues are they found? What is the mode of transmission?
Skin, oropharynx, and nose (nose-type is most infectious) Respiratory droplets
What are the two exotoxins of anthrax?
EDEMA FACTOR: adenylate cyclase which enters host cell and is activated by calmodulin LETHAL FACTOR: disrupts signal transduction for cell division
What is Tx for botulism?
Stomach lavage (irrigate stomach to remove toxin) Horse antitoxin Supportive care, possibly including respiratory support
What are the clinical syndromes of gas gangrene Clostridium perfringens (name 4 progressive syndromes)?
1) cellulitis 2) necrotizing cellulitis (invasion of the dermis and underlying capillaries) 3) necrotizing cellulitis (invasion of facia around muscle) 4) myositis or myonecrosis (invasion into the muscle)
What are normal flora in the Upper Respiratory Tract?
Similar to oral flora Nose: S aureus Throat: Viridan Streptococci, Neisseria, and S. eidermidis Anaerobes: Bacteroides, Fusobacterium, Clostridium, Peptostreptococcus
Is Bacteriodes fragilis resistant or sensitive to penicillin?
Penicillin RESISTANT
What are the two clinical variants of botulism besides food? (we’ve mentioned these earlier)
Infant botulism Wound botulism
Bacteriology of Staphylococcus saprophyticus… gram stain and distinctive features.
G + Coagulase negative (S. epidermidis and saprophyticus are neg. S. aureus is positive) Catalase + (distinguishes from Strep) Resistant to novobiocin
What is Tx for… C. tetanus C. botulism C. difficile C. perfringens
C. tetanus: Vaccine. Human anti-tetanus IgG. Supportive therapy. Respiratory support. C. botulism: botulism type-specific antitoxin and supportive therapy. Respiratory support. C. difficile: Stop prior antibiotic. Tx with vancomycin, metronidazole, or fidaxomicin C. perfringens: Surgical debridemnet and penicillin
What is a common disease related to normal oral cavity flora? (hint: it is not in the oral cavity)
Aspiration pneumonia caused by aspirating one’s own oral secretions aka passing out at late night parties
What is the virulence factor of Group A Strep pyogenes S. pneumococcus
1) M protein and capsule 2) Capsule, pneumolysin, IgA, protease
In terms of catalase, compare Staph from Strep.
Staph = catalase Strep = NO catalase
What kind of hemolysis do Streptolysin O and Streptolysis S cause (alpha, beta, or gamma)?
Beta
Botulism Dx… Clinical or lab or both?
Usually clinical Dx Culturing microorgansim is not suggested because the preformed toxin is the culprit. However, detecting the toxin is a useful lab Dx
What are the catalase vs coagulase status of S. aureus S. epidermidis S. saprophyticus
Which staph are Catalase + and Coagulase + Catalase + and Coagulase - Catalase + and Coagulase -
What is Tx for pneumococcus? What must be determined for adaquate Tx?
Multiple antibiotic resistance is frequent. May be penicillin resistent Sensitivity testing is required
What is the Dx for C. tetani… Clinical vs lab or both?
mainly clinical Dx and Hx the organism is rarely still in the wound the exotoxin causes symptoms
What are the names of the non-spore forming anaerobic gram + rods?
Bifidobacterium Corynebacterium Lactobacillus Actinomyces Clostridia (some form spores) are covered in a prior lecture Note: Bifidobacterium is not needed for exam. Corynebacterium and Lactobacillus are also deemphasized.
With the Lactose Egg Yolk Agar test what Clostridia do what?
C. perferingens are lechithinase + on egg yolk and ferment lactose C. botulism are Lipase + on egg yolk and protease + on milk C. tetani have tennis racket spore C difficile is what is left
What is the lab Dx for Clostridia species?
Lactose Egg Yolk Milk Agar coupled with microscopy See Slide 17
Which have hemolysis S. aureus S. epidermidis S. saprophyticus
S. aureus has hemolysis (alpha toxin)
What is the general pathogenesis of Gas Grangrene Clostridium perfringens? (details follow)
synthesize many toxins and enzymes which lyse host cells and tissues: necrosis
What do the cytokines do the superantigens of the enterotoxin or TSST-1 elicit?
IL-1 IL-2 TNF
How are Group A streptococci further subdivided?
Analysis of their M proteins divides Group A into 90 types There is a schema of Streptococcus pyogenes on page S-2
What are the clinical syptoms of C. diff?
diarrhea (usually watery, sometimes bloody) with yellowish-white plaque pseudomembranse on colonoscopy
What is Hepatic Coma and how can bacteria be involved?
Bacteria are a major source of ammonia in the blood. Liver converts ammonia to urea and amino acids. If the liver is impaired, high blood ammonia can cause coma. Antibiotics may be used to treat. Cathartics and enemas are also used to reduce intestinal bacteria.
Explain the differences between Glomerulonephritis and Rheumatic Fever… Major symptoms?
Glomerulonephritis: edema, hypertension, hematuria Rheumatic fever: carditis, polyarthritis, subcutaneous nodules, skin lesions (erythema marginatum)
What are 2 possible pathogenic steps in establishing bacterial infection by ingesting toxin?
1) Toxins are pre-formed in food and ingested. No organism necessary. (ex: Botulism and S. aureus) 2) Ingestion of microorganism with adherence, colonization, and toxin is then formed in the gut. (ex: Botulism and Vibrio cholerae aka cholera toxin)
What are common bacteria found in the colon (7)?
1) Bacteroides 2) Bifidobacterium 3) Lactobacili 4) Clostridia 5) Coliforms and Enterococcus 6) More than 400 other anaerobes 7) small amounts of aerobes, such as S. aureus, Pseudomonas, Proteus, Klebsiella
There is some natural stasis in th ileum that allow bacteria to grow. (<10^6) What bacteria are found in the terminal ileum?
Resemble colon bacteria E. coli, enterobacter, and other gram - are common Anaerobes, such as Bacteroides fragilis also predominate (RESISTANT TO PENICILLIN)
What is the bacteria and spore shape of Clostridium botulism?
Gram + rod with subterminal oval spores Spore location is not diagnostic
What is Dx of Gas Gangrene Clostridium perfringens? Name three major and three minor Dx criteria
CREPITUS of due to gas in subcutaneous tissue DISCOLORATION and edema of skin EXTREME PAIN also… dark serous exudates gram stain of exudates culture of wound X-ray
What is the Dx for food poisoning Clostridium perfringens?
ELISA enterotoxin in feces or implicated food
What is the aerobic status, invasive status, gram stain, shape, and speed of growth of Clostridium perfringens?
Anaerobic, INVASIVE, gram + rod, grows VERY rapidly
What are the major causes and concerns with hospital Staph infections?
IV catheters or other implanted devices Resistance to Methicillin and even Vancomycin High mortality and high costs
