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 (Z-pac) 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

• How can gonorrhea be treated?

• 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