Test #6: Unusual Bacteria And Gram-(+) Bacteria Flashcards
Mycoplasma pneumoniae
-unusual bacteria
-reservoir: humans
-Wall-less- cannot do gram stain
-Sterols in plasma membrean
-Pleomorphic
-Reservoir: human infected
-Transmission: droples
-Primary atypical or walking pneumonia
-Mild symptoms: low fever, cough
-Dx:
-Antibody titer
-Molecular test- DNA Probe or PCR
enriched media
-Colonies looked at microscopically
-3wks to grow
-Treatment: no cell wall- antibiotics have to act on something else
tetracycline/doxycycline- inhibits protein synthesis
-Healthy young people
-no vaccine
Gram-(+) Staphylococcus
-All species are catalase (+)
-Clusters and tetrads
Staphylococcus aureus
-Reservoir: vaginal area and skin?
-Growth on blood agar: beta-hemolytic
-Coagulase (+)
-Clear background
(cloudy background= (-))
-Ferments mannitol
-Folliculitis, stye, furuncle (boils)
-These sites of infections are cultures
-bullous impetigo (in children less than 2 years of age)
-scalded skin syndrome- peels skin
-Ecfolitative (ex)otoxin
-Toxic shock syndrome
-Fever, low BP, rash, vomiting, shock
-Vaginal culture- for Rely tampons
-Staphylococcus (food) intoxication
-From food at room temp
-Enterotoxin (exotoxin) is not destroyed by heating
-Self-limiting
-Nausea, vomiting, diarrhea
-Transmission: droplets, direct contact (highly contagious)
-Abscess- collection of pus, bacterial fluid
-Drained
-Gram-stain and culture site of infection
-Clots protects it from phagocytes
Methicillin resistant S. aureus
-Strain resistant to penicillin
-Nosocomial (hospital acquired) or community acquired
-athletes and immunocompromised people are susceptible
-May lead to death in immunocompromised pt’s
-Starts as a wound
-Then leads to boils and abscess
-Transmission: direct contact
-Prevention: handwashing, PPE
-To isolate- must call infectious control and nurse (must isolate pt)
-Contact and body fluid isolation
-Treatment: vancomycin
-dx:
-blood agar- blood sample(blood infection is suspected) nasal swab
-Oxacillin disk diffusion test:
This test determines if the bacteria are resistant to oxacillin, an antibiotic similar to methicillin
-PCR
-coagulase (+)
-facultative aerobe
-optimal temp: 35-37
-virulence factors:
-forms biofilms
Staphylococcus epidermidis
-Reservoir: skin virulence
-Forms biofilms via glycocalyx
-Transmission: Opportunistic route (skin, in nasopharynx) or nosocomial route
-Dx:
-Culture: blood agar, catheter tip
-prevention: handwashing
-Does not ferment mannitol
-Blood agar: Non-hemolytic
-Coagulase (-)
-catalase (+)
1) blood infections in immunocompromised persons or babies
2) infections associated catheter for IV lines
-Treatment: vancomycin
-signs and symptoms: (may vary) red, swollen, and painful bumps or boils, joint pain
-facultative anaerobe
-optimal temp.: 35-37
-nonmotile
Streptococcus pyogenes
-Reservoir: infected humans
-Beta-hemolytic on BAP; susceptible to bacitracin
-Taxo “A” disk
-CO2 jars overnight- 24hrs- 37 degrees celsius
-Transmission; droplets, fomites
-Rebecca Lancefield- serogroup
Serogroup A
-Tonsillitis or pharyngitis/strep throat
-Fever, sore throat, redness, pus
-Throat swab- rapid antigen test (could get false (+) or false (-)- so must do throat culture
-Treatment: penicillin and erythromycin
-Could progress to scarlet fever if not treated
-Starts to produce Erythrogenic toxin (exotoxin)
-Rash, strawberry tongue, fever
-Rheumatic fever
-Inflammation of heart valves
-Autoimmune complication of S. pyogenes infections
-Antibodies to S. pyogenes cross react w/ heart tissue
-Causes lysis of tissues- destroys heart valves
-Fever, murmur, joint pain
-Impetigo old than 2 yrs old
-Contagious through direct contact and droplets
-Crusted lesion
-Erysipelas
-Erythrogenic toxin
-Reddening of skin , rash
-Necrotizing fasciitis
Exotoxin A could damage fascia, cause tissue necrosis (tissue not getting enough O2- black appearance)
-Flesh-eating
-If antibiotics do not work, may have to amputate
-Wound or tissue culture
-Catalase (-)
-coagulase (-)
-Beta-hemolytic on blood colonies
-aerotolerant
-nonmotile
-nonendospore formin
Streptococcus agalactiae
-Lancefield Group B
-causes Group B streptococcal infection
-Beta-hemolytic
-Catalase (-)
-coagulase (-)
-Resistant to bacitracin (Taxo “A” disk)
-Reservoir: Normal vaginal flora, GI tract
-Transmission: perinatal route, opportunistic
-Neonatal meningitis
-Spinal fluid, blood sample, urine sample
-facultative anaerobe
-Signs and symptoms:
-children: fever, trouble feeding, lethargy
-adults: UTI, blood infection, or pneumonia
-dx:
-blood, spinal fluid, or urine, or by screening pregnant women with vaginal or rectal swabs
-blood agar
-treatment: penicillin
Streptococcus pneumoniae
-Gram-(+) diplococcus
-Reservoir: Nasopharynx, upper respiratory tract
-If it spreads- causes infection
-Encapsulated, gram-(+) diplococcus, Alpha hemolytic, susceptible to optochin- Taxo “P” disk
-Greening of agar
-Virulence factors:
-biofilms
-Lobar pneumonia
-transmission: droplets
-Fever, chest pain, bloody sputum, difficult to breath
-Treatment: penicillin or other antibiotics
-Older than 65 yr old, immunocompromised, asthma- vaccine
-Middle ear infection (otitis media)
-Transmission: endogenous route (disease arising from an infectious agent or condition that is already present within the body, rather than being introduced from outside)
-Fever, pain, temporary deafness
-Treatment: antibiotics, ear tubes, rem tonsils
-causes antibiotic-resistant pneumonia
-causes pneumonia only when the cells are protected by a polysaccharide capsule. Unencapsulated S. pneumoniae cells cannot cause (pneumococcal) pneumonia and are readily phagocytized.
-transmission: droplets of
-prevention: vaccine
-in pts of older than 16, 80% of meningitis cases are now caused by Neisseria meningitidis and Streptococcus pneumoniae
-virulence factors:
-capsule
-pneumolysin allows bacterium to enter meninges
-dx:
-blood or cerebrospinal fluid- blood agar
-antigen testing w/ sputum or urine
-gram stain
-catalase (-)
-coagulase (-)
Streptococcus viridans
-gram-(+)
-Clinical specimen: blood culture
-fever
-Reservoir: throat, mouth, normal flora, GI tract, female genital tract
-Main cause of endocarditis
-Valve damage, murmur
-also causes cavities
-Alpha hemolytic colonies on BAP
-Pinpoint (tiny), greening
-Transmission: dislodgement during dental procedures
-Predisposed heart condition
-Must take antibiotic before dental visit
-Dx:
-Blood culture
-Catalase (-)
-coagulase (-)
-Resistant to optochin
-Treatment: penicillin and other antibiotics
-erythromycin resistance
Enterococcus faecalis
-Nonhemolytic (gamma)
-Blood agar
-gray
-Bile Esculin agar
-Differential - hydrolysis of Esculin- black colonies
-Vancomycin resistance (VRE- more serious than MRSA)
-Infection control
-Causes nosocomial uti, septicemia, wound infections
-Opportunistic or nosocomial routes
-causes treatable bacterial infections that may soon be untreatable w/ -antibiotics
-facultative anaerobes
-reservoir: GI tract, soil, water (hospitals), plants
-dx:
-blood or urine sample
-gram stain
-catalase (-)
-coagulase (-)
Gram-(+) bacilli: Bacillus anthracis
-Gram-(+) endospore forming
-O2 needed to sporulate- facultative anaerobe
-Clear endospores
-In chains, pairs
-Anthrax
-Transmission: cutaneous (break in skin, black scar- necrosis or gastrointestinal
-starts as painless, itchy bump- develops into blister- then black scab
-Endospore germination
1) edema exotoxin
2) Lethal exotoxin- necrosis
3) inhalation anthrax (Woolsorter’s Disease)
-Dx: gram stain, endospore stain, culture (BSL-3 nonmotile), PCR (amplify nucleic acid)
-Treatment: antibiotics- ciprofloxacin
-Prevention: vaccine- animals, risk groups
-Chest x-ray
-Inhale endospores
-virulence factors:
-capsule
-facultative anaerobe
-nonmotile
-reservoir: domestic livestock
-transmission: direct contact w/ hides or animals; air; food
-exotoxins type A-B
-dx:
-sample: blood, skin lesion,cerebrospinal fluid, sputum
-PCR (can be used to detect the presence of B. anthracis DNA in samples)
-serological tests: Blood tests can detect antibodies or toxins produced by B. anthracis.
-catalase (+)
-coagulase (-)
Clostridium
-Anaerobic (obligate)
-jar /chamber
-Box-shaped rod
-gram-(+) endospore forming
-Reducing media
-Thioglycolate broth
Clostridium tetani
-rod-shaped in pairs or chains
-anaerobic
-Transmission: Parenteral routes (puncture or wound)
-Endospores germinate and tetanus (exotoxin) is released- tetanospasmin
-neurotoxin A-B
-causes tetanus
-Signs and symptoms: Violent spasmodic muscle contractions, Lockjaw
-Dx: endospore stain and anaerobic culture of wound
-Treatment: antibiotic and antitoxin (antibody to exotoxin)
-Prevention: vaccine
-reservoir: soil, GI tract of animals (horses), manure
-Other tests may be used to rule out other conditions: Such as meningitis, rabies, or strychnine poisoning, if the patient presents with similar symptoms.
-catalase (-)
-coagulase (-)
Clostridium botulinum
-strict (obligate) anaerobe
-rod-shaped pairs or chains
-spores eliminated by commercial sterilization
-Reservoir: *soil, intestinal tracts of animals
-Transmission: ingesting botulism, honey in babies, inhalation of endospores
-Botulism:
-Pt history
-Signs and symptoms: blurred/double va, paralysis, respiratory failure
-Toxin assay on food/serum/stool
-neurotoxin A-B
-Anisera (antibody to botulism exotoxin A-E)
-Infant Botulism
-Treatment: antitoxin, supportive therapy (respiratory aid)
-Floppy baby syndrome
-Honey ingestion less than 12 mo
-No vaccine
-dx:
-blood or stool sample
-on blood agar- beta hemolytic
-catalase (-)
-coagulase (-)
Clostridium difficile
-Opportunistic: human normal flora- intestinal tract (reservoir)
-transmission: fecal-oral route
-Endogenous: hands of health care works- if not washing hands
-Endospores germinate
-Exotoxins release
-Toxin A- diarrhea, watery stool
-Toxin B- colon damage, colitis
-Pseudomembranous colitis
-Antibiotic- associated diarrhea
-Dx: detect toxin A and B in stool samples= active infection (carriers may not test (+) for toxins); PCR (1st)- detects DNA (amplified) of infection
-Treatment: vancomycin, fidaxomicin, fecal transplant (similar to probiotics)
-signs and symptoms: diarrhea, colitis
-dx:
-PCR (DNA of C dif)
-stool tests
-blood tests
-colonoscopy
-blood agar- gamma hemolytic
-catalase (-)
-coagulase (-)
Listeria monocytes
-reservoir: soil, water, vegetation, and animal feces
-Foodborne, can be transmitted to fetus
-mother-to-child: cross the placenta and infect the fetus during pregnancy
-blood transfusion
-direct contact w/ infected animals
-Meningitis in immunocompromised persons (and new bornes)
-Gram-(+) short rods
-Multiply in macrophages (in immunocompromised pt’s)
-Dx: gram stain and culture of blood of spinal fluids
-Blood agar- beta-hemolysis
-Catalase (+)
-PCR
-coagulase (-)
-Motile
-Newborn meningitis
-Signs and symptoms: fever, lethargy, headache, and rash
-Treatment: ampicillin
-Nonendospore forming
-virulence factors:
-motility
-acid tolerant- survives in stomach acid
-grows at low temp
Chlamydia trachomatis
-reservoir: human
-Obligate intracellular bacteria- must be in host cell to grow
-Dx: cell culture, DNA probes, antigen tests, PCR
-catalase (-)
-coagulase (-)
-conjunctivitis
-transmission: birth canal,
swimming pool
-treatment: tetracycline
-Can lead to pneumonia
-Transmission: sexual route, perinatal route
-trachomaChronic inflammation of eyelids, corneal scarring, blindness
-Can spread to other parts of pelvis (PID)
-Can also spread to uterine tube (serious- ectopic pregnancy)
-Male- urethritis (nonspecific)
-Spread: Hand-eye contact, fomites, insects
Mycobacterium tuberculosis
-Gram-(+) rod
-Acid-fast- mycolic acid in cell wall
-Resistant to phagocytosis
-Multiplies inside alveolar macrophages
-Non-endospore forming
-Transmission: droplets, aerosols
-Signs and symptoms: coughing up blood, fever, fatigued, weight loss, night sweats
-reservoir: humans
-Risk groups: homeless, AIDS pt’s, travel to areas where disease is prevalent
-Screening:
1) purified protein denature (PPD test) of M. tuberculosis- skin test (can get false results)
2) chest x-rays
-Dx: Acid fast staining (red rods, blue background), growth on Lowenstain Jenson agar- sputum sample (3-6 wks), DNA probe
-catalase (+)
-coagulase (-)
-Treatment: drug combo: Isoniazid, Ethambutol, rifampin
Rickettsia rickettsii
-diverse collection of obligately intracellular Gram-negative bacteria found in ticks, lice, fleas, mites, chiggers, and mammals
-fever, headache, rash, and muscle aches, including conditions like Rocky Mountain spotted fever, epidemic typhus, murine typhus, and scrub typhus
-gram-(-) rods
-dx:
-serological tests:
-Immunofluorescence assay (IFA)
-A common serologic test that detects the body’s immune response to the infection
-Acute and convalescent serologic testing
-Requires a blood sample taken within the first week of illness and another 2–10 weeks later
-Molecular tests
-Polymerase chain reaction (PCR): A molecular test that identifies the rickettsia bacteria
Biopsy of rash: A biopsy of the rash can be stained with fluorescent antibodies to detect organisms
-treatment: doxycycline
-pleomorphic
Corynebacterium diphtheria
-club-shaped gram-(+) bacteria (bacilli)
-nonendospore forming
-reservoir: humans
-transmission: droplets, direct contact, contaminated objects
-diphtheria toxin (A-B)
-cytotoxin- ➖ protein synthesis in nerve, heart, and kidney cells
-causes diphtheria
-prevention: vaccine
-severe infection of nose or throat
-A sheet of thick, gray matter covers the back of the throat, making breathing hard.
-signs and symptoms: sore throat, fever, swollen lymph nodes, and weakness
-treatment: antibiotics and an antitoxin that neutralizes the diphtheria toxin
-vancomycin
-travel history
-dx:
-throat or skin swab culture
-gram stain
-Polymerase Chain Reaction (PCR) assays can be used to detect the DNA sequence encoding the A subunit of the toxigenic strain
-catalase (+)
-coagulase (-)
Micrococcus
-gram-(+) psychotrophic (contamination is the primary reason for the premature spoilage of pasteurized milk; grow at refrigeration temperatures, and depending on the species) cells which are thermoduric (may survive pasteurization
-reservoir: skin of humans and other animals and in soil, marine and fresh water, plants, fomites, dust
-treatment: antibiotics (vancomycin)
-transmission: common skin bacterium, is transmitted through direct or indirect contact with contaminated objects or surfaces, and potentially via inhalation of contaminated droplets or aerosols.
Mycobacterium leprae
-bacillus, slightly curved
-microaerophile
-non motile
-usually grown in armadillos, which have a relatively low body temperature that matches the requirements of the microbe
-optimal growth temp: 30 degrees Celsius
-These bacteria have never been cultured on artificial media. They can be cultured in armadillos and mouse footpads.
- causative agent of Hansen’s disease/leprosy
-damages the peripheral nerves and targets the skin, eyes, nose, and muscles
-signs and symptoms: lose of sensation in skin, disfiguring nodules
-transmission: prolonged contact w/ contaminated secretions
-treatment: Daspone, rifampin, clofaximine
-prevention BCG vaccine
-dx:
-acid-fast
-skin biopsy
-PCR test
-catalase (-)
-coagulase (-)
-reservoir: humans
Micrococcus luteus
-gram-(+)
-nonmotile
-non-endospore forming
-gamma-hemolytic
-reservoir: soil, water, dust, and air
-causative agent of: bacteremia, endocarditis, septic arthritis, and peritonitis
-treatment: vancomycin
-transmission: direct or indirect contact with contaminated surfaces or objects, and potentially via inhalation of contaminated droplets or aerosols
-dx:
-gram stain
-MALDI-TOF) mass spectrometry (MS) is a technique that identifies microorganisms like bacteria, fungi, viruses, and protozoans
-oxidase (+)
-catalase (+)
-coagulase (-)
-blood agar- cream-yellow colored colonies
-does not ferment mannitol
-does not ferment carbs
-opportunistic pathogen, leading to infections in immunocompromised individuals, and can cause skin infections, septic shock, and nosocomial infection
-vaccine: no
Streptococcus mutans
-causes dental carries
-dx:
-alpha-hemolytic
-saliva/plaque samples
-PCR test
-catalase (-)
-coagulase (-)
-facultative anaerobic
-virulence factors:
-capsule- uses as a source of nutrition by breaking it down and utilizing sugars when energy⬇️
-attaches to teeth by its glycocalyx
-signs and symptoms: discolorization or hole in tooth enamel
-treatment: rem of decayed area
-prevention: flossing, brushing, reducing dietary sucrose
-reservoir: mouth
-transmission: sharing utensils, contaminated water
