BIO2302 Chapter 18&20: Gram-Negative Pathogens

gram-negative cells are ___ (less/more) complex than gram-positive, so there are ___ (less/more) negative bacteria

more, more

gram-negative cell walls consist of a thin layer of ___ surrounded by an ___ ___

peptidoglycan, outer membrane

The outer membrane is composed of lipids, lipoproteins and __________________

lipopolysacchairde

Are there teichoic acids in gram-negative cell walls

no

LPS consists of three parts

lipid A, core polysaccharide, O side chain (O antigen)

___ ___ embedded in the outer membrane (LPS)

lipid a

___ ___ and ___ ___ ___ extend out from the cell (LPS)

core polysaccharide, O side chain

The Family Neisseriaceae are residents of ___ ___ of warm-blooded animals

mucous membranes

2 primary human pathogens of Neisseriaceae

Neisseria gonorrhoeae, Neisseria meningitidis

Genus Neisseria are strict ___, do not survive long outside of the host

parasites

Genus Neisseria produce ___ and cytochrome oxidase

catalase

Genus Neisseria -- pathogenic species require ___ complex media (chocolate agar)

enriched

Neisseria gonorrhoeae causes ___, an STD

gonorrhea

modes of transmission for Neisseria gonorrhoeae:

sexual contact

Neisseria gonorrhoeae portals of entry

urogenital tract

Neisseria gonorrhoeae portals of exit

secretions

Neisseria gonorrhoeae gram reaction, morphology, arrangement

gram negative intracellular diplococci

Neisseria gonorrhoeae oxygen classification

aerobe

major Neisseria gonorrhoeae virulence factors

fimbriae, IgA protease

fimbriae (virulence factor)

surface molecules for attachment, slows phagocytosis

IgA protease (virulence factor)

cleaves secretory IgA

gonorrhea is stritly a __ infection

human

genital gonorrhea in the male, urethritis

yellowish discharge, scarring, and infertility

vaginitis. urethritis, salpingitis (PID)

mixed anaerobic abdominal infection

vaginitis. urethritis, salpingitis (PID) are a common cause of ___ and ___ ___ ___

sterility, ectopic tubal pregnancies

anal intercourse can lead to ___ (extragenital gonococcal infection)

proctitis

oral sex can result in ___ and ___ (extragenital gonococcal infection)

pharyngitis, gingivitists

careless personal hygiene can account for self-inoculation of the ___ and a serious form of ___ (extragenital gonococcal infection)

eyes, conjunctivitis

in small number of cases, the gonococcus enters the bloodstream and is disseminated to the ___ and ___ (extragenital gonococcal infection)

joints, skin

gonococcal infections in children

Infants born to gonococcus carriers are in danger of being infected as they pass through birth canal

gonococcal infections in children can cause

eye inflammation, blindness

___ and ___ tract of neonates might also be affected by gonococcal infections

pharynx, respiratory

gonococcal infections in children are prevented by ___ immediately after birth

prophylaxis

are females or males more asymptomatic to gonnococcal infections

females

is there a vaccine for Neisseria gonorrhoeae

no

treatment of Neisseria gonorrhoeae

combination of antibiotics

Human reservoir for Neisseria meningitides in the ____, 3-30% of adult population

nasopharynx

Neisseria meningitides portal of entry

bloodstream (crosses blood-brain barrier)

Neisseria meningitides portal of exit

respiratory secretions

Neisseria meningitides gram reaction, morphology, arrangement

gram-negative diplococci

Neisseria meningitides oxygen classification

aerobic

Neisseria meningitides major virulence factors

capsule, adhesive fimbriae, IgA protease, ENDOTOXINS

meningococcal disease

release of endotoxins during meningococcemia may cause hemorrhage, coagulation, and vascular damage, leading to necrosis of tissues

meningococcal disease can cause crops of lesions called ___ that develop on the trunk and appendages in half of the cases

petechiae

septicemia

infection in the blood

high risk individuals for Neisseria meningitides

living in close quarters, children 6 months-3 years, young adults (10-20s)

is there a vaccine available for Neisseria meningitides

yes

Neisseria meningitides is treated with IV ___ ___ and ___

penicillin G, cephalosporin

___ treatment of family members, medical personal, or children in close contact with patient with Neisseria meningitides

prophylactice

primary vaccine of Neisseria meningitides contains specific purified ___ ___

capsular antigens

aerobic gram-negative nonenteric bacilli have a wide range of habitats:

large intestines (enteric), zoonotic, respiratory soil, water

all aerobic gram-neg nonenteric bacilli have ___ ___ ___ of the cell wall

outer membrane LPS

Pseudomonas aeruginosa is a common inhabitant of ___ and ___

soil, water

Pseudomonas aeruginosa is an ___ resident in 10% normal peple

intestinal

Pseudomonas aeruginosa is resistant to

soaps, dyes, QUAT disinfectants, drugs, drying

Pseudomonas aeruginosa are frequent contaminants of

ventilators, IV solutions, anesthesia equipment

Pseudomonas aeruginosa is a(n) ___ pathogen

opportunistic

Pseudomonas aeruginosa is a common cause of ___ infections in hosts with ___, ___ ___, ___ ___

nosocomial, burns, neoplastic disease, cystic fibrosis

Pseudomonas aeruginosa complications include ____, ___, ____, ___, and ___ ___

pneumonia, UTI, abscesses, otitis, corneal disease

Pseudomonas aeruginosa has a ___-___ pigment

green blue

Pseudomonas aeruginosa gram reaction/morphology/arrangement

gram neg rods

Pseudomonas aeruginosa oxygen classification

aerobe

Pseudomonas aeruginosa major virulence factor

endotoxins

is there a vaccine available for Pseudomonas aeruginosa

no

treatment of Pseudomonas aeruginosa

strong combination therapy (multi-drug resistant)

reservoir of Bordetella pertussis

apparently healthy carriers

transmission of Bordetella pertussis

direct contact or inhalation of aerosol

Bordetella pertussis portal of entry

respiratory tract

Bordetella pertussis portal of exit

respiratory droplets

Bordetella pertussis gram reaction/morphology/arrangement

gram negative minute, encapsulated coccobacilli

Bordetella pertussis oxygen classification

aerobe

What are the receptors of Bordetella pertussis responsible for?

They recognize and bind to ciliated respiratory epithelial cells.

What is one of the major effects of Bordetella pertussis toxins?

They destroy and dislodge ciliated cells.

What role do adhesins and toxins play in Bordetella pertussis?

They mediate the disease.

Name toxins produced by Bordetella pertussis.

Pertussis toxin, adenylate cyclase toxin, dermonecrotic toxin, tracheal cytotoxin

What is the consequence of the loss of ciliary mechanism due to Bordetella pertussis?

It leads to buildup of mucus and blockage of the airways.

Bordetella pertussis causes ___ or ___ ___, a communicable childhood afflication

pertussis, whooping cough

time course for progression of pertussis

incubation, catarrhal, paroxysmal, convalescent

incubation (pertussis)

no symptoms

catarrhal (pertussis)

rhinorrhea, sneezing, malaise, fever

paroxysmal (pertussis)

repetitive cough with whoops, vomiting, exhaustion

convalescent (pertussis)

diminishing cough, possibly secondary complications

is there a vaccine for Bordetella pertussis

yes, DTaP

DTaP is an ___ vaccine with ___ and other antigens

acellular, toxoid

many members of enterobacteriaceae inhabit

soil, water, decaying matter, large bowel of animals

enterobacteriaceae are divided into:

coliforms and non-coliforms

coliforms

lactose fermenters

non-coliforms

non-lactose fermenters

complex __ ___ contribute to pathogenicity and trigger immune response

surface antigens

H (surface antigens)

flagellar antigen

K (surface antigens)

capsule and/or fimbrial antigen

O (surface antigen)

somatic or cell wall antigen

Not all species carry the __ and ___ antigens, but all have the __, implicated in endotoxic shock

H, K, O

The pathogenesis of enterics is also ties to their production of ___ and ___

endotoxins, exotoxins

most prevalent enteric bacillus

E. coli

Enterohemorrhagic E. coli (EHEC)

hemorrhagic syndrome and kidney damage

Enterohemorrhagic E. coli (EHEC) are ___-toxin producing

shinga (STECs)

shiga-toxin

The toxin enters the host cell, binds ribosomes, and disrupts protein synthesis, leading to death and shedding of intestinal cells

shiga-toxin dissemination leads to ___ ___ ___

hemolytic uremic syndrome

Enterotoxigenic E. coli (ETEC)

severe diarrhea due to heat-labile toxin and heat-stable toxin