Test #5: Gram-(-) Bacteria And Spriochetes: Chapter 11, 21-26 Flashcards
Borrelia borgdorferi
-causes Lyme disease
-gram-(-) spriochete- stains very faint pink color
-spreads through blood
-cause: deer tuck
-transmission: vector (arthropod or bug bite)
-reservoir: mice (which larva of deer tick feeds on)
-signs and symptoms: bull’s eye rash (Erythema Migrans)- at site of bite, nonspecific flu-like symptoms of rash is not present
-late stage: multiple E. Migrans rash, cardiovascular and neurological symptoms (Bell’s palsy, meningitis, cephalitis), arthritis
-dx: ELISA (1st, indirect) and western blot (2nd) (serology)
-will show if you have antibodies to B. borgdorferi
-treatment:
-early stages
-antibiotics: doxycycline (can enter nervous system), tetracycline
-➖ protein synthesis
-later stages:
-more antibiotics
-treat symptoms
-prevention:
-avoid tick exposure
-use personal protection measures
-perform tick check and rem tick (w/ forceps/tweezers)
-vaccine: no
Treponema pallidum
-gram-(-) spirochete
-long, thin spirals
-causes syphilis
-seen w/ special stain or dark field microscopy (to see live movement)
-reservoir: humans
-transmission: sexual or congenital (during birthing process)
-stages of syphilis:
-primary: hard, painless genital sore
-secondary: rash (anywhere on body, often in palms of hands, soles of feet, and forearms)
-latency: no signs or symptoms, but possibly still transmissible
-tertiary: gummas (rubbery lesions) anywhere in body; may cause cardiovascular and neurological symptoms
-dx:flourescent treponemal (indirect) antibody test (FTA-ABS- 2nd)
-serology detect antibodies to T. Pallidum
-and RPR (rapid plasma reagin- 1st)
-treatments: penicillin, quinolones
-interferes w/ cell wall synthesis
-vaccine: no
-catalase (-)
-coagulase (-)
Enterobacterial (enterics)
-gram-(-) rods
-peitrichous flagella- covers entire cell surface
-faculative anaerobes
-ferment glucose and other carbs
Escherichia coli
-most common cause of UTI (and cystitis (bladder) and pyelonephritis (1 or both kidneys)
-reservoir: GI tract of humans
-opportunistic routes (already in intestinal tracts, and gets to urinary tract) or (nosocomial route- ex. Catheter) hospital acquired
-signs and symptoms: frequent, painful urination (dysuria), back (flank) pain, fever
-dx: urine culture, urinalysis
-blood agar
-beta hemalytic
-indole production from
tryptophan metabolism (urinalysis)
-lactose fermenter
-treatment: antibiotics (ex. Quinolones- kills/➖ bacteria)
-UTI may cause sepsis
-catalase (+)
-coagulase (-)
Proteus mirabilis
-gram-(-) rod
-can be involved in UTIs (but E. coli is the most common cause
-opportunistic or nosocomial route
-wave-line growth on blood agar (swarming) of urine culture
-non-hemolytic
-multiple flagella (very motile)
-non-lactose fermenter (clear colonies)
-urease production
-urea➡️ammonia (alkaline pH)
-powered by urease
-reservoir: human GI tract
Salmonella
-gram-(-) rod
-common cause of gastroenteritis in the U.S.; >2400 servers- serogroup (cell wall antigens)- serotyping
-overt pathogen (always causes disease)
-reservoirs: GI tract of reptiles (including chickens)
-transmission: fecal-oral route or contaminated foods (ex. Raw poultry, unpasteurized eggs- medium of spread)
-will get into intestinal tract and invade (salmonellosis- disease)
1) Salmonella enters an epithelial cell
2) Salmonella multiplies w/in vesicle (infection) inside the cell
3) Salmonella multiplies in mucosal cells; there the inflammatory response in diarrhea
-symptoms: nausea, vomitting, abdominal pain, diarrhea, fever
-virulence factors:
-fimbriae
-catalase (+)
-coagulase (-)
Salmonella enterica
-reservoir: humans, animals, environment
-transmission: fecal-oral or vehicles (meat, vegetables, fruits, salad, water)
-dx: stool culture; serotyping-serogroup
-treatment: self-limiting; fluid and electrolyte replacements
Salmonella typhi
-reservoir: human feces
-transmitted by contact w/ human feces, not animals
-cause typhoid fever/enteric fever- shock, death
-dx: blood culture, serotyping
-quinolones: interfer w/ nucleic acid synthesis
-vaccine preventative
-can be carried in liver, spleen, gallbladder
-virulence
-capsule
-endotoxin in cell wall
-perforations (holes) and ulcers in intestines
-high fever
-carriers: harbors bacteria and sheds it indefinitely in all secretions but does not have disease
-vaccine
Shiga toxin
-not all shigella produce this toxin
-Found in contaminated food, such as undercooked beef, unpasteurized milk, and contaminated water.
-no natural reservoir in animals (infected humans)
-component of bacteria that cause shigellosis
-gram-(-) rod
-exotoxin
Shigellosis
-fecal-oral or vehicles (food or water as medium for transmission)
-bloody diarrhea
1) shigella enters the epithelial cells (infected)
2) shigella multiplies inside the cells
3) shigella involves neighboring epithelial cells thus avoiding immune defenses
4) an abscess forms an epithelial cell killed by the infection. The bacteria rarely spread into bloodstream (but does cause mucosal-intestinal abscess)
Shigella
-Bacillary Dysentery
-bloody diarrhea
-transmission: fecal-oral; vehicle (poor sanitation)
-dx: stool culture, stereotyping
-MacConkey agar
-gram stain for stool samples
-WBCs in stool
-quinolones
Enterohemorrhagic E. coli (0157: H7)
-gram-(-) straight rod
-serious strain of E. coli
-shiga toxin-producing E. coli causes hemolytic uremic syndrome (HUS)
-cause anemia, damage RBCs and kidneys
-most common strain of E. coli that causes bloody diarrhea, colitis, kidney damage, hematuria
-close contact w/ calves at diary farm or petting zoos (fecal-oral, vehicles (raw beef, salad, spinach, unpasteurized juice)
-dx: stool cultures- sorbital MAC agar; DNA fingerprinting- gene for shiga toxin (non-pore forming toxin that ➖ protein synthesis w/in target cells. It is produced by a type of E. coli known as “shiga toxin-producing E. coli” or STEC)
-treatment: fluids and electrolytes, renal dialysis
-reservoirs: GI tract of cattle
Non-enterobacteriaceae: Pseudomonas aeruginosa
-gram-(-) rod
-straight rod- no curves
-reservoir: water, soil, environment (including hospital)
-creates biofilms (resistant to disinfectant and antibiotics)
-polar flagella
-transmission: opprotunistic or nosocomial routes
-beta-hemolytic
-shows blue-green pigmentation on TSA
-MAC: non-lactose fermenter, colonies clear- no dark pink centers
-grape/sweet odor (typical of Pseudomonas)
-common post-burn wound infection (causes green pus)
-causes dermatitis (rash from hot-tubes: resistant to chlorine, no treatment-self-limiting needed), UTI (not as common as E. coli), and swimmer’s ear (Otitis External; chlorine resistant; antibiotic gtts)
-culture site of infection
-does not ferment glucose or lactose
Campylobacter jejuni
-curved gram-(-) rod- seagull-like appendage
-CAMPY agar at 42 degrees Celsius (incubated- similar to chicken’s GI tract)
-microaerophile- lower O2
-48hrs
-gram stain: pink-gray color
-transmission: fecal-oral routes; vehicles
-dx: stool culture onto CaMPY agar
-unpasteurized/raw milk and juice, raw meat (especially poultry), water
-treatment: fluid and electrolyte replacement- for healthy people; immunocompromised people: antibiotics
-signs and symptoms: gastroenteritis, watery diarrhea, vomitting
Helicopter pylori
-makes urease to live in acidic pH of stomach
-carcinogen
-cause stomach ulcers
-multiple flagella (4 grouped together; polar)
-curved
-urease converts to ammonia (more like alkaline pH- causes stomach acid to ⬆️pH)
-fecal-oral routes and endogenous route (already in stomach then multiplied and goes to sterile area)
-Begins to make exotoxins that cause damage stomach lining
-Gastric bx then stain tissue
-chocolate agar
-Signs and symptoms: vomiting, pain-epigastric, dark stool
-Tests: stool sample
-Suggested causes of ulcers
-Fecal-oral
-Gastric bx, antigen or antibody tests for dx
-Antibiotics and Pepto-Bismol
-Acid suppressors
Vibrio cholera
-causes cholera
-Gram-(-), motile (flagella), comma-shaped bacilli
-Reservoir: salty water, ocean
-source : raw oysters
-Halophiles
-Found in coastal waters
-Massive water diarrhea, dehydration, thirsty, shock, lethargy, mental disturbance, coma, dry skin
-Sign: Rice-water stools
-Endemic in Latin America
-Dx: stool cultures, selective and differential media
-Treatment: antibiotics and fluids and electrolytes
-Prevention: water disinfection; oral vaccine
Nesseria meningitidis
-gram-(-) diplococci
-Transmission:
-respiratory route
-Carriers
-Inert objects (not as common)
-Reservoir: upper respiratory system (nasopharynx)
-Virulence factors
-Capsule
-Fimbriae- adherence
-Endotoxin- in cell wall, LPS
Septic shock and fever
-Effects nervous system via bloodstream
-Inflammation of meninges
-Meningococcal meningitis
-Signs and symptoms: Severes headache, sensitive to light, fever/vomiting, stiff neck, rapid breathing, rash (Petechial rash- later stage)
-Treatment and Prevention
-Vaccine
-Collect blood or spinal fluid (spinal tap)
-Gram stain and culture (chocolate agar, 37 degrees celsius)
Rapid Antigen testing- detect capsule antigen (agglutination test)
Legionella pneumophila
-Gram-(-) coccobacilli/rod (tiny)
-Virulence factors
-Multiply in alveolar macrophage- trying to phagocytize this bacteria- unable; grows inside macrophages
-Biofilms
-Capsule
-Transmission: vehicles (air, water- inhaling water); not person-to-person
-Legionnaires’ Disease (pneumonia)
-Signs and symptoms: coughing, chest pain, difficulty breathing
-Treatment: erythromycin
-Sputum sample- culture and gram stain
-Does not grow quickly (7-14 days to culture)
-Fluorescent antibody test (detect antigen), urine antigen test (serogroup 1), DNA probes (rapid- test sputum directly)
-Media selects for Legionella and enriched
-Gray, speckled colonies
-Risk groups: heavy smokers, elderly, immunocompromised
-no vaccine
Bordetella pertussis
-Causes whooping cough
-Stage 1: Catarrhal stage (1-2wks- common cold symptoms)
-Stage 2: Paroxysmal stage
-Violent coughing bouts
-Stage 3: Convalescence stage
-Cyanosis- tissues in facial skin can’t contain O2 from mucus accumulation
-Return to healthy state by being treated w/ antibiotics during stage 2
-Treatment and prevention: antibiotics and supportive therapy and vaccine
-Gram-(-) coccobacilli to rod-shaped
-Reservoir: human infected
-Contagious- spreads easily
-Virulence factors
-Capsule- neutrophils unable to phagocytize
-Pertussis exotoxin
-fimbfiae
-Damages cilia
-Transmission: respiratory droplets
-Dx: Nasopharynx swab culture
-7-14 days to culture
-Enriched and selective media
-Capsule antigen detection
-Fluorescent microscope
-ELISA test w/o fluorescent microscope
-PCR test- w/o serology (faster)
Haemophilus influenzae
-Gram-(-) coccobacillus to rod
-Encapsulated H. influenza type b (has a capsule) caused meningitis in children < 4 years old
-Very fastidious- needs a lot of CO2
-Reservoir: nasopharynx
-Can get into epiglottis (epiglottits- trouble breathing), meninges and ear canal
-Hib vaccine
-Dx: gram stain, X (heme) and V (NAD) factors for growth
-Chocolate agar (37 degrees celsius, high CO2)
-Cephalosporins
-Known encapsulate H. influenzae Could cause conjunctivitis (eye culture), otitis media (middle ear infection)- endogenous route (in upper respiratory system then infects sterile site)
-Chocolate agar
-Transmission: respiratory droplets
-Get viral flu and develop secondary pneumonia in immunocompromised pt’s and alcoholics
-Treatment: antibiotics
Neisseria gonorrheae
-Gram-(-) diplococcus
-Coffee bean-shaped
-Reservoir: humans
-Transmission: sexual route, perinatal route
-Virulence factors
-Antigenic variation (escape host antibodies)
-IgA protease (escape host antibodies)
-No life long immunity to gonorrhea- can get more than once
-Fimbriae- attach to other cells/surface- adhere to sperm and get to fallopian tube
-Males: many signs and symptoms
-Dx: gram stain (mostly for men)
Cervicitis (in women- endocervix specimen- could spread to other areas in pelvis> Pelvic Inflammatory Disease- which can spread to joints) and arthritis (joint pain)
-Ophthalmia neonatorum- pus from baby’s eye
-Treatment silver nitrate/antibiotic gtts
-Dx: Eye culture
-Dx of gonorrhea
-Culture of ENdocervix or urethral pus onto Thayer Martin Agar
-Chocolate agar + antibiotics
-Kept in CO2
-24-48hrs
-Serology test to detect antigens
-DNA probes (urine, molecular methods)
-PCR (urine, molecular methods)
-Antibiotics resistance
-Ceftriaxone used
-Cannot use penicillin
-no vaccine
Gardnerella vaginalis
-causes bacterial vaginitis
-gram-variable rod
-highly pleomorphic
-facultative anaerobic
-catalase and oxidase (-)
-reservoir: female vagina, urethra, and rectum
-transmission: During sexual intercourse, Gardnerella vaginalis can be transferred from the infected partner’s vagina or penis to the other partner’s vagina.
It can also be transmitted through oral sex.
-dx:
-gram stain
-vaginal pH testing: high pH (above 4.5)- abnormal
-signs and symptoms: thin gray, white or green fluid coming from the vagina, fishy smell from the vagina, an itchy vagina, or burning while urinating
-treatment: antibiotic: metronidazole
Mycoplasma pneumoniae
-causes walking pneumonia
-unusual bacteria
-rod
-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
-Contains sterols
-3wks to grow
-Treatment: no cell wall- antibiotics have to act on something else
-tetracycline/doxycycline- inhibits protein synthesis
-Healthy young people
Chlamydia trachomatis
-causative agent of trachoma
-oval shaped, gram-(-)
-lacks peptidoglycan cell wall
Reservoir: humans
-anaerobic
-Obligate intracellular bacteria- must be in host cell to grow
-Dx: cell culture, DNA probes, antigen tests, PCR
-nucleic acid amplification test (NAAT)- urine, vaginal or urethral swabs
-Cause conjunctivitis in baby
-Can lead to pneumonia
-Transmission: sexual route, perinatal route
-Chronic inflammation
-Can spread to other parts of pelvis (PID)
-Can also spread to uterine tube (serious- ectopic pregnancy)
-Male- urethritis (nonspecific)
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
List at least six characteristics used to classify and identify bacteria according to Bergey’s.
-Cell Morphology
-Differential staining (gram stain, acid-fast)
-Oxygen requirements
-Motility
-Nutrition
-Metabolic properties
Yersinia pestis
-negative, non-motile, coccobacillus
-both Yersinia enterocolitica and Yersinia pseudotuberculosis, the pathogen from which Y. pestis evolved and responsible for the Far East scarlet-like fever.
-dx:
-Microscopic examination
-Examine stained smears of blood, lymph nodes, or sputum for small Gram-negative rods
-Look for bipolar-staining with Wright, Giemsa, or Wayson stains
-Blood cultures
-A sensitive way to isolate Y. pestis
-Blood should be collected into tubes with citrate, EDTA, or heparin
-Serologic tests
-Take a serum specimen early in the illness and a convalescent sample 4-6 weeks later
-Confirm a positive test result with a second test
-Nucleic acid amplification
-Use PCR to identify Y. pestis in blood, sputum, CSF, or bubo aspirates
-Use portable real-time quantitative PCR thermocyclers in the field
-reservoir: rodents and their fleas. This is called an enzootic cycle.
-transmission: bite of infected fleas
-signs and symptoms:
-Bubonic Plague:
-Swollen, painful lymph nodes (buboes), typically in the groin, armpits, or neck
-Fever
-Chills
-Headache
-Muscle aches
-Fatigue
-Pneumonic Plague:
-Fever
-Chills
-Cough, often with bloody sputum
-Chest pain
-Shortness of breath
-Septicemic Plague:
-Fever
-Chills
-Weakness
-Bleeding under the skin or from the nose, mouth, or rectum
Organ failure
-treatment: streptomycin and gentamicin, or doxycycline and ciprofloxacin. This is especially important for patients with severe or resistant infections. Fluids, O2, and pain relievers
