Transcript Neisseria and Enterobacteraceae

Jumpstart 4/9
•
Get a book from the cart (hint ch. 30 and
31)
Answer the following questions:
1. What bacteria causes gonorrhea?
2. What bacteria causes bubonic plague?
Neisseria and
Enterobacteraceae
Medical Microbiology
Spring 2010
Neisseriaceae
• Family of bacteria with 4 genera, 2 are
strictly pathogenic and the other 2 are
normal flora—we are only going to look at
1 of them
• Gram negative cocci, typically arranged in
pairs (diplococcus)
Characteristics of Neisseria
• Gram negative diplococcus
• Do not form spores
• Most are catalase positive too (makes it
easy for laboratory detection)
• Have pili that extend from the membrane
– Allow attachment to hosts
– Exchange of genetic material
Neisseria cont.
• Pathogenic species need iron to grow and
compete with their human hosts for iron.
• The type that we will focus on is Neisseria
gonorrhoeae
Virulence Factors
• Pilin- attachment
• Por protein- keeps them from being destroyed
by the immune system easily
• Opa protein- firm attachment
• Rmp protein- protects surface antigens from
being destroyed
• 3 proteins for acquiring iron
• LOS (lipooligosaccharide) endotoxin
• An enzyme to destroy penicillin
Neisseria gonorrhoeae
• Causes the disease gonorrhea
– Occurs only in humans
– 2nd only to chlamydia as the 2nd most
commonly reported bacterial STD in the US
– About 300,000 cases per year are reported
– Highest incidence is in the age group 15-24
– Transmitted primarily by sexual contact
• Only about half of infected women
experience symptoms (other half are
asymptomatic). Men almost always
experience symptoms.
• Chance of acquiring the infection if sexual
contact with an infected person:
– If female, 50%
– If male, 20%
Gonorrhea
• Signs and symptoms
– Depends on the gender and location of the
infection
Gonorrhea in males
• Mostly restricted to the urethra
– Purulent urethral discharge
– Dysuria (painful urination)
• Swelling of epididymis, prostate may occur
Gonorrhea in females
• Primarily restricted to the cervix
• Not able to infect the vagina
• Signs and symptoms
– Vaginal discharge
– Dysuria
– Abdominal pain
– PID
– Ovarian abcesses
Diagnosis
• Swab infected area and do a gram stain
• Oxidase/catalase postitive
Treatment
• Penicillin was the drug of choice for years
– You already know why not so much anymore
(think about its virulence factors)
– Also makes them resistant to erythromycin,
tetracycline, aminoglycosides
– In Asia and Pacific islands, we also see
resistance to Cipro
• Now, drug of choice is Azithromycin (Zpac) or doxycycline
Enterobacteriaceae
• You have 10 minutes to read and take
notes on the structure and physiology of
enterobacteriaceae
Group Time
I sneakily wrote a number on your paper while you
were taking notes. Get with your group.
#1’s: E. coli
#2’s Salmonella
#3’s: Shigella
#4’s:Yersinia (my fav)
#5’s: Klebsiella
#6’s: Treatment, Prevention, and Control
Jumpstart 4/13
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How can gonorrhea be treated?
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Name 3 ways that Enterobacteriaceae is
different from Neisseria.
E.coli
• Escherichia coli
• Capable of causing sepsis, UTIs,
meningitis, gastroenteritis
• 2 major virulence factors
– Adhesins: allow it to stick cells and not be
flushed away
– Exotoxins
E. Coli
• Large numbers of E. coli are found in the
GI tract
• Major cause of UTIs (80% of UTIs are
caused by E.coli
• Common cause of gastroenteritis in
developing countries
Gastroenteritis (E. coli)
• EPEC (enteropathogenic):
– Small intestine, causes infant diarrhea;
watery, nonbloody
• ETEC (Enterotoxigenic):
– Small intestine, “traveler’s diarrhea” and infant
diarrhea; cramps, nausea, low-grade fever
Gastroenteritis, cont
• EHEC (Enterohemorrhagic)
– Large intestine; bloody diarrhea, no fever
• EIEC (Enteroinvasive)
– Large intestine; watery diarrhea, may
progress to dysentery with bloody stool
• EAEC (Enteroaggregative)
– Small intestine, infant/traveler’s, persistent
Salmonella
• Ingested and travel to the stomach where
they can survive the harsh conditions
• Colonizes nearly all animals
• Most infections result from infected foods
(fecal/oral)
• Most notorious species is Salmonella
typhii
Salmonella, cont.
• Gastroenteritis
• Septicemia
• Enteric fever (typhoid)
– Malaise, fever, headache, gastrointestinal
problems
Shigella
• Common cause of dysentery (S.
dysenteriae)
– Exotoxin called Shiga toxin that disrupts
protein synthesis and damages endothelial
cells
• Causes shigellosis
– Abdominal cramps, diarrhea, fever, bloody
stools
Yersinia
Read the information provided and answer the following
questions:
1. Between 1347 and 1351, how many people died from
bubonic plague?
2. What is the main source of Y. pestis?
3. Describe how a bite from this organism may lead to
the plague.
4. Describe several impacts of the Black Plague.
5. Should we be concerned with the plague returning?
Why or why not?
6. Create a mini-timeline on your notebook paper to
represent the history of the plague.
Klebsiella
• Prominent capsule
• Can cause pneumonia
Treatment
• Some infections do not require antibiotic
treatment, just treat symptomatically.
– E. coli and Salmonella infections can be
prolonged by antibiotic use
• For other infections, streptomycin