Exam 4 Flashcards
Neisseria (genus)
Gram negative non-motile aerobic bacteria diplococcic arrangement
Neisseria gonorrhea
Capsule + Fimbriae Antigens on surface frequently change shape Persistent infection Men experience: painful urination (inflammation),pus-filled discharge Women Experience: vaginal discharge 50% asymptomatic Can affect newborns (eye infection) can result in ectopic pregnancy
Diplococci observed (discharge) oxidase test for cytochrome c oxidase (purple if +)
Neisseria gonorrhea
N. gonorrhea treatment
broad spectrum antibiotics
many resistant strains
Neisseria meningitides
humans are only natural carriers
can be nomral microbiota (upper respiratory)
transmitted by respiratory droplets
Meningitis (disease)
Inflammation of lining of the CNS
Meningococcal meningitis: bacteria invade cerebrospinal fluid, can result in death as early as 6 hours after symptoms
Meningococcal septicemia: bacteria in blood release toxins that damage blood vessels. formation of minute hemorrhagic lesions (petechiae)
Can produce blood coagulation and result in gangrene
Presence of gram negative diplococcic cells in the CNS
Meningitis
Meningitis treatment
intravenous penicillin
Prophylactic treatment of exposed individuals
Eradication is unlikely due to too many asymptomatic carriers
Enterobacteriaceae (family)
All are gram negative rods oxidase negate reduce nitrate to nitrite look similar Typically intestinal microbiota ubiquitous Not all have virulence factors
Enterobacteriaceae coli
gram negative rod prefers anaerobic Most are harmless and some are even mutualists (make Vitamin K) Indicator organism (fecal contamination)
Gastroenteritis (also cause UTI’s) is the most commonly caused disease of this organism
Exotoxins and cellular rearrangement produce signs and symptoms
virulent strains have virulence genes on the plasmids
E. Coli
Entertoxigenic E. Coli
traveler’s diarrhea (Mexican water)
non-invasive
toxin causes watery diarrhea
best treated with rehydration and pepto (bismuth)
Enterinvasive E. coli
Dysentery like disease
invades intestinal wall
results in inflammation and fever
Enteropathogenic E. coli
infant diarrhea (watery) fever, vomiting
Enterohemorrhagic E. coli
Causes hemorrhagic colitis
associated with hemolytic uremic syndrome (severe kidney disorder) in children and elderly
toxin
Klebsiella pneumonia
gram negative non-motile rod prefers anaerobic capsule normal member of skin, mouth, and the intestinal flora
Klebsiella pnemonia pathogenicity
Produces a capsule that protects the bacteria from phagocytosis
gives the colonies a mucoid appearance
Serratia marsecans
produces a red pigment when grown at room temp
can grow on catheters, in saline and other hospital supplies
Opportunistic of immunocompromised patients in urinary and respiratory tracts
Proteus mirabilis
gram negative
prefers anaerobic
gliding motility (forms rings on plate)
found on any dead and decaying matter
Organism demonstrates gliding motility
Urease test (rapid)
contains urea and an acid / base indicator
turns pink at high pH
Proteus mirabilis
Type III secretion systems inject proteins that inhibit phagocytosis, rearrange the cytoskeleton of eukaryotic cells, or induce apoptosis
Truly pathogenic enterobacteriaceae
Salmonella (genus)
gram negative motile rod prefers anaerobic found in intestines of birds, reptiles, and mammals Truly Pathogenic
Salmonella typhimurium salmonellosis
typical salmonella
causes fever, cramps, diarrhea, and vomiting
Low mortality rate (infants and elderly)
Death is generally from sceptic shock
organism can actually punch through epithelial walls and into the bloodstream
Salmonella typhi
Cause of typhoid fever
Humans are only known host
Transmission via oral / fecal route
Reduced in first world, but still kills .5 million anually
Incubates for 2-3 weeks in body (causes fever, headaches, diarrhea)
Gastroenteritis: ulceration and perforation of intestinal wall are possible, bacteria can pass through the intestines into blood.
Can survive phagocytosis
S. Typhi treatment
re-hydration
250+ doses of chloramphenicol
remove gallbladder
vaccination is available (live attenuated Ty21a) taken orally and protects for up to 7 years
Shigella (genus)
gram negative
non-motile
primarily a parasite of human gi tract
produces a diarrhea inducing enterotoxin
Shigellosis clinically relevant species and treatment
sonnei
flexneria
dysenteriae: disease is more serious
treat with fluid and electrolytes
Yersinia species
Y. enterocolitica: fecal oral, causes intestinal inflamation
Y. pestis: bubonic plague
Bubonic plague
Pneumonic Plague
Y. pestis is the cause
spreads person to person
characterized by high fever and swollen lymph nodes (buba)
Pneumonic is from a flea / parasite and is a rapidly developing lung infection
Haemophilus (genus)
small
pleomorphic (no set shape)
bacilli
Obligate parasite (require heme and NAD+ for growth)
Flu
Haemophilus influenza
most common form of meningitis of infants prior to HIB vaccine use
Can also cause skin infections, sepsis, and more
Bordetella pertussis
Gram negative
non-motile
short rods
aerobic
Whooping Cough
Bordetella pertussis
attaches to ciliated epithelial cells in the lungs via filamentous hemagglutinin (type of adhesion)
pertussis toxin aids attachment and prevents phagocyte response
Tracheal cytotoxin inhibits cilia movement on respiratory cells
Whooping cough diagnosis and treatment
Inspiratory “whoop” along with… vomiting after cough, subconjunctival hemorrhages, rib fractures, incontinence, hernias, facial hematomas.
symptoms are enough to diagnose
Treat by managing symptoms, anti-bacterials have little effect unless taken early
Immunize with DTaP
pseudomonas aeruginosa
gram negative, rod, motile, aerobic
can live in any moist environment
can grow in distilled water
nor part of normal microbiota
Pseudomonas aeruginosa disease
can colonize almost any organ
opportunistic off immune-compromised patients
Possesses a capsule, numerous fimbriae, and adhesins that allow for attachment to human cells
Numerous toxins inhibit protein synthesis in eukaryotic cells
Pseudomonas aeruginosa treatment
The organism is resistant to many antibiotics
Capable of gene transfer across the biofilm
Quinolone seems effective despite this
Legionella pneumophila
Ubiquitous inhabitant of water
can survive range of temps
will quickly die when heated to 60C for 30 minutes or exposure to chlorinated water
Disease travels via aerosols, no known human-human transfer
Predominantly colonize respiratory track, organism invades and proliferates in phagocytes.
Legionellosis
Pontiac fever: mild respiratory disease
Legionnaire’s disease is more severe
Pseudomonas aeruginosa diagnosis
catalase positive
beta-hemolytic on blood agar
produces pyocyanin
Vibrio (genus)
gram negative, motile, oxidase positive, curved rods
all species are salt tolerant and some require at least .5% salt to grow
found in estuarine and marine environments
Vibrio cholera
Ingest contaminated water or food
Severe abrupt watery diarrhea (due to toxin) and vomiting
“rice water stool” (indicative with organisms in stool)
Causes severe fluid and electrolyte loss
01 E1 Tor is a very virulent and widespread strain
Cholera toxin
Two subunits A and B
B binds and A is cleaved off and enters the epithelial cell
A1 initiates enzyme cascade converting AMP to cAMP
cAMP stimulates secretion of electrolytes (Cl- and Na+) into the lumen. water follows
How is water cleaned of cholera on the cheap?
The bacteria is found on the plankton which is easily filtered out with silk over a bucket
Causes gastroenteritis and wound infections and can result from bad shellfish or washing wounds in sea water
Vibrio parahaemolyticus and vulnificus
vulnificus wounds can take the form of blistering dermatitis
Chlamydia (genus)
No cell walls
two membranes with no peptidoglycan between them
Can only grow and multiply inside the phagosome of the cell (obligate intracellular parasite) (this is the only way to reproduce)
Chlamydia life cycle
Elementary body (EB) attaches to host cell receptor enters via endocytosis converts to Reticulate body (RB) in food vesicle rapid division, some switch back to EB before cell ruptures
Chlamydia trachomatis
Only two known hosts; us and mice
Infects conjunctiva of the eye which scars and eyelashes turn backward which abrades the eyes
can infect newborns at birth or transmission by flies
Chlamydia trachomatis treatment
500 million cases worldwide, 8 million cause blindness
Treat promptly with antibiotics and surgical correction
proper hygiene prevents re-infection
Chlamydia LGV
STD form (and most common std)
Small, painless lesions around genitals
Painful urination / intercourse, discharges, inflammation
Lymphogranuloma Venereum: may cause buboes
90 million new cases anually (1-4 in US)
Antibiotics are effective
General characteristics of a Eukaryote
Membrane bound organelles
80s ribosome
nucleus
undulating flagella
Haploid and diploid refer to
the number of complete copes of the cell’s genome
1 and 2
Interphase
Step 1
DNA replicates
Mitosis
Step 2
an equal partitioning of replicated DNA between two nuclei
2n to 2n
Cytokinesis
Step 3
cytoplasmic division
cleavage or in the case of yeast, budding
Meiosis
An equal partitioning of replicated DNA between four nuclei
2n to 1n
Schizogony
Multiple rounds of mitosis form a multinucleate cell called a schizont
Multiple rounds of (mitoses and) cytokinesis form several merozites
occurs mostly in parasitic protozoans
Protozoa
Unicellular
ubiquitous
motile (pseudopodia, cilia, flagellum)
Protozoan nutrition
Most are chemo-organo-heterotrophs Predators of bacteria and each other Feed on decaying organic matter Consume host tissues Some are photosynthetic while others are mixotrophs (both)
Trohpozoite
Free living motile feeding stage of a protozoan
Cyst
resting stage that allows cells to survive unfavorable conditions
not a reproductive structure
pass from intestines of one host to another
Dinoflagellates (phylum)
Two (unequal in length) flagella:
- Transverse (spin)
- Longitudinal (propulsion)
Gonyaulax (genus)
Produce yessotoxin (kills fish at high concentrations)
If highly concentrated in shellfish then it can harm humans
Photosynthetic red pigments (cause of red tide)
Pfiesteria (genus)
Possible estuary associated syndrome (PEAS)
produce potent neurotoxin
parasite of fish
Chagas Disease
Trypanosoma Cruza = kinetoplastid: organism with a single large mitochondrion
Zoonotic reservoirs: opossums and armadillos
transmission by kissing bug
T. Cruza life cycle
???
Stages of Chagas disease
Acute: swellings (chagomas) occur at site of bite
Generalized: fever, swollen lymph nodes, heart inflammation
Chronic: asymptomatic (months to years)
Symptomatic: heart failiure
Chagas disease diagnosis and treatment
xenodiagnosis: allow kissing bug feeding of patient, then disect for evidence of growth 4 weeks later
Treat early stages with antiparasitic: benznidazole, nifurtimox (60% cure rate)
Later stages require surgery and transplant
Giardia intestinalis
lives in intestines of humans and animals
four pairs of flagella
Two equal sized nuclei
Form cysts and have an adhesive disk (organism resembles ToV boss)
Giardia intestinalis life cycle
ingestion of cysts: fecal oral or water
Cysts release a trophozoite when activated by stomach acid which enters intestines
Giardiasis
Often asymptomatic
can cause severe watery diarrhea, ab pain, nausea, vomiting, foul-smelling stool (rotten egg)
Usually 1-4 weeks, but can be reinfected (dog eating poop)
Beaver fever
Amoebic Meningoencephalitits
Naegleria fowleri
swimmers infected when they inhale trophozoites from water
Infect nasal mucosa and travel up olfactory nerve to brain
Primary: loss of smell, headavhe, fever, vomiting, stiff neck (3-5 days)
Secondary: hallucinations, confusion, ataxia (loss of muscle control)
Death within 3-7 days or primary symptoms
Treat with antiparasitics
Chitin in the cell wall?
Must be a fungi
Yeast
small, globular, single cells
Mold
Long branched tubular hyphae
Mycelium
Intertwined mass of hyphae (can even become visible to unaided)
Fungi reproductive structures
Yeasts: buds
Mushrooms and molds: spores (sporangia, conidia, basidia) easily dispersed
Chlamydospore: resting structure that survives unfavorable conditions
Haustoria
structure that allows a fungi to obtain nutrients from a living organism (modified hyphae)
Commonly found in moist soils with high N levels (bat caves)
Two strains / variants
Histoplasma Capsulatum:
- Var. capsulatum
- Var. dubiosii
True pathogen
Histoplasmosis
H. capsulatum
Healthy folk develop immunity with minor symptoms
5% develop a clinical case: chronic pulmonary, severe coughing, bloody sputum
Often confused for tuberculosis, but antibiotics will do nothing
Histoplasmosis Diagnosis and treatment
Diagnosis: culture and observe morphology Hyphae seen at <30C and spiny spores yeasts grow at 37C Treatment: ketoconazole amphotericin B
Ketoconazole
prevents formation of fungal cell membrane (ergosterol)
amphotericin B
punches holes in fungal cell membranes
True pathogenic fungi
Blastomyces dermatidis
Coccidiodes immitis
Histoplasma capsulatum
Paracoccidiodes brasiliensis
One of the few fungi to be transmitted from person to person
Normal microbiota of skin
Candida albicans
Candidiasis
symptoms depend on infected area and type
white plaque in the mouth
cloudy vision and lesion within the eye
Yeast infections: prolific growth after normal bacterial microbiota are disrupted (change in vaginal pH)
Candidiasis diagnosis and treatment
look for budding yeasts
treatment depends on location
topical for skin
oral nystatin (works like amphtericin b)
vaginal use of azole creams and suppositories or oral fluconazole
Aspergillus niger
ubiquitous and opportunistic pathogen of potentially anywhere on the body
Typically molds fruits
Aspergillosis pulmonary
hypersensitivity:
asthma or allergic reactions to inhaled spores
non-invasive: ball like masses of hyphae in lungs (aspergillomas) [asymptomatic]
acute-invasive: severe lung damage (surgical action necessary)
Aspergillosis non-pulmonary
Growth in sinuses, ear canals, conjunctivas
acellular infectious agent
virus
bacteriophage
insert genetic material directly into host cell
dsDNA
d20 on a pillar with legs
Lytic Cycle
xxx
Lysogenic
Happens between steps two and three of lytic cycle
xxx
Animal viruses
Entire virus is taken in by cell, often have an envelope
glycoprotein spikes instead of tails
direct entry
a pore is created for the viral genome
membrane fusion
two membranes come together and fuse (like liquid drops). A hole is created for the capsid to insert
endocytosis
entire virus is endocytized
DNA viruses use the (___) to replicate while RNA viruses use the (___)
nucleus
cytoplasm
Poxviridae (family)
dsDNA pleomorphic capsule and envelope infection via close contact and inhalation (droplets or crusts) envelope is unstable outside of host species immunity for many strains
Degrees of Lesions
Macule: flat red
Papule: raised
Vesicle: clear fluid
Pustule: opaque pus
Orthopoxvirus variola
smallpox virus
initially infects the internal organs then moves out to skin
1978 last natural case, Janet Parker was last death
Herpesviridae (family)
HHV 1 - casual contact (often children)
HHV 2 - STD
enveloped, polyhedral capsids, dsDNA
most prevalent DNA viruses
remains inactive inside infected cells until ready for a reoccurence
HHV 1 - casual contact (often children)
HHV 2 - STD
latent infections hang out in the ganglia
Syncytia
cells with the virus fuse with adjacent cells and spread the virus
Varicella-Zoster virus
HHV 3
causes chicken pox and shingles
Papillomaviridae
dsDNA, naked, icosahedral capsid
papillomas: benign growths (warts) on epithelium
seed warts
fingers and toes
cauliflower appearance
planar warts
soles of the feet
flat warts
trunk, face, knees
cauliflower appearance with a bed of red surrounding
Rhinovirus (genus)
naked, +ssRNA
It’s a cold
meds can relieve symptoms, but the symptoms are how your body fights back. you might as well just ride it out
Orthomyxovirus
enveloped, -ssRNA, segmented
flu virus
Influenza
orthomyxovirus
Morbilivirus (genus)
enveloped, unsegmented, -ssRNA
Measles
Caused by morbilivirus which infects respiratory track then spreads Characteristic lesions (Koplik's spots) in mouth
Retroviridae (family)
most studied virus group
genome contains two identical molecules of +ssRNA
polyhedral capsule with spiked envelope
Virus transcribes dsDNA from ssRNA (which is backwards to every organism on earth) [possible with reverse transcriptase]
HIV
replicates in our immune cells and destroys them
Immunity prevented because of antigenic variability with gp120 (facilitates attachment) and gp41 (fusion)
AIDS
not a disease
AIDS is any of a certain opportunistic or rare infection that:
- occurs in presence of antibodies against HIV
- a CD4 white blood cell count below 200 cells / micro-liter of blood
Treat with reverse transcirptase inhibitors and fusion inhibitors
Lytic Cycle
- Virus attaches
- Entry (injection of viral DNA)
- Virus starts to take over
- Virus chops up host chromosome and enzymes injected with DNA. Phage DNA is replicated, transcribed to RNA, and translated
- Viral proteins are made
- Assembly of viral proteins
- cell is ruptured via lysis, and the new viruses released
Lysogenic Cycle
Lysogeny happens between entry and virus take over (2 and 3)
- Host chromosome is left in tact an the viral DNA is inserted
- the bacteria grows and divides, replicating virus with it
- When virus feels threatened it chops up genome and resumes Lytic cycle
