Gram Negative Bacteria Flashcards
What are the general characteristics of all Vibrio spp.?
Curved rods, facultative anaerobes, obligate halophiles, oxidase positive, flagella
Bordet-Gengou or Regan-Lowe media are required for growth of what G- bacteria?
Bordetella pertusis
What clinical diseases may result from N. gonorrhoeae infection?
Gonorrhea, pelvic inflammatory disease, purulent arthritis, pustular rash, ophthalmia neonatorum (purulent eye infection in neonates)
What Enterobacteriaceae genera ferment lactose?
Escherichia, Klebsiella, Enterobacter, Citrobacter
What are the G- cocci genera?
Neisseria spp.
Moraxella spp.
What diseases are associated with Acinetobacter baumannii?
Respiratory tract infections, UTIs, wound infections, septicemia, nosocomial infections
A patient is infected with a G- diplococci bacteria. The bacteria is catalase positive, oxidizes only glucose, and is grown on Thayer Martin media. What bacteria is infecting the patient?
N. gonorrhoeae
What G- bacteria are especially important pathogens in patients with cystic fibrosis?
Pseudomonas aerugionas & Burkholderia cepacia complex
Pertusis is associated with what G- bacteria?
Bordetella pertusis
What clinical dieases are associated with Camplyobacter?
Gastroenteritis (C. jejuni & C. coli only)
Guillain-Barre syndrome (nerve tingling)
Reactive arthritis (immune-mediated)
Sepsis, meningoencephalitis (C. fetus only)
What are the characteristics of pseudomonads?
Nonfermenting, obligate aerobe, oxidase positive, catalase positive, beta hemolytic
Chancroid (STI that produces painful ulcers and lymphadenopathy in the genital region) is associated with what G- coccobacilli?
H. ducreyi
What virulence factors are associated with V. cholera?
Cholera toxin, toxin co-regulated pilus, neuraminidase, cholera enterotoxin, zona occuldens toxin
How does Salmonella infect the body?
The bacteria invades M cells and entrocytes in the small intestine. They replicate and may be transported through cells and released into the blood of lymphatic circulation.
What are the medically relevant Neisseria spp. bacteria?
N. gonorrhoeae
N. meningitidis
K antigens define what bacterial antigens?
Capsular antigens
What G- bacilli is highly virulent and responsible for the plague?
Y. pestis
What is the common transmission route for Helicobacter pylori?
Fecal/oral
G-, bacilli, lactose non-fermenter, H2S producing, urease positive, and swarming motility are all characteristics of what bacteria?
Proteus mirabilis
Entertoxigenic E. coli (ETEC) is the leading cause of what clinical disease?
Travler’s diarrhea
Hektoen agar is a selective and differenital media used to distinguish between which two G- bacteria genera?
Shigella (does not produce H2S) & Salmonella (H2S producing)
What virulence factors are associated with V. vulnificus?
Capsule, cytolysins, proteases, collagenase
What clinical diseases are caused by N. meningitidis?
Meningitis & meningococcemia
What viruelnce factors are associtaed with E. coli?
Adhesins, heat-labile toxin (increases cAMP), heat-stable toxin (increases cAMP), shiga toxin
The flagellar antigens are associated with which antigen classification?
H antigens
What clinical diseases are associated with Shigella infection?
Watery diarrhea, dysentery
Localized infections only. High level of leukocytes in stool
Escherichae, Klebsiella, Proteus, Salmonella, Shigella, and Yersinia belong to what bacterial family?
Enterobacteriaciae
What G- bacteria typically result in nosocomial infections and are most common in patients on broad or longterm antibiotic use?
Acinetobacter baumanni & Stenotrophomonas maltophilia
What are the relevant Vibrio species?
V. cholera, V. parahaemolyticus, V. vulnificus
What are the G- rod genera?
- Escherichiae spp.
- Klebsiella spp.
- Proteus spp.
- Salmonella spp.
- Shigella spp.
- Yersinia spp.
- Pseudomonas spp.
- Burkholderia spp.
- Acinetobacter spp.
- Stenotrophomonas spp.
H. aegyptius is assiocated with what clinical diseases?
Purulent conjunctivitis (children)
Hemorrhagic colitis (bloody diarrhea) is caused by which type of E. coli?
Shiga-toxin producing E. coli (STEC)
Who is at greatest risk for Stenotropomonas maltopholia infecion?
Patients on longterm antibiotics
What are the characteristics of Acinetobacter baumannii?
Coccobacillus, oxidase negative
What are the morphological and biochemical characteristics of Moraxella catarrhalis?
Diplococcus, aerobe, oxidase positive, beta lactamases
(part of normal flora in nasopharnyx)
This sexually transmitted disease results in painless ulcers and inguinal lymphadenopathy. What bacteria causes this disease?
K. granulomatis
What are the general characteristics of all Campylobacter spp.?
Thin, comma-shaped rods, motile, oxidase positive, catalase positive, microaerophilic, capnophilic, LOS membrane, capsule, optimal growth slightly above body temperature
UTIs with cystitis or pyelonephritis are associated with infection by what bacteria?
Proteus mirabilis
What are the G- curved rod genera?
Campylobacter spp.
Helicobacter spp.
Vibrio spp.
Thermostable direct hemolysin that induces Cl- secretion and movement of H2O out of the cell is associated with which Vibrio spp.?
V. parahemolyticus
How does P. aeruginosa display antibiotic resistance?
Intrinsic - slow rate of antibiotic movement into cells
Acquired resistance - via conjugation or mutation
Adapative resistance - expression of resistance genes turned on in response to stimuli
What viruelnce factors are associated with Yersinia spp.?
Type III secretion system
Y. pestis - capsule, plasminogen activator protein (degrades complement and fibrin), siderophores
What agar is always used to culture N. gonorrheae and often N. meningitidis?
Thayer Martin - Selective chocolate agar with antibiotics
What clinical diseases are associated with M. catarrhalis infection?
Sinusitis & otitis media (children)
Brronchitis & bronchopneumonia (elderly parients with chronic pulmonary disease)
What virulence factors are associated with C. jejuni?
Capsule, adhesins, cytotoxic enzyme, eneterotoxin
What are the medically relevant Haemophilus bacteria?
H. influenzae
H. ducreyi
H. aegypitus
What are the medically relevant Camplyobacter spp.?
C. jejuni
C. coli
C. fetus
What populations are at greatest risk for N. meningitidis infection?
Individuals with complement deficiencies, college students
What are the characteristics of Haemophilus spp.?
Coccobacilli, faculative anaerobes, IgA proteases, capsules (only some)
What clinical diseases are associated with H. influenzae infection?
Otitis media & sinusitis (children)
Bronchopneiumonia (elderly with COPD and smokers)
Meningitis & epiglottitis (rare)
What are the medically significant Yersinia spp.?
Y. pestis, Y. enterocolitica, Y. pseudotuberculosis
What agar is needed to grow Vibrio spp.?
Thiosulfate citrate bile salts sucrose (TCBS)
What clinical diseases are associated with Y. enterocolitica & Y. pesudotuberculosis infection?
Enterocolitis (parimarily children), septicemia, arthritis, intrabdominal abscesses, hepatitis, osteomyelitis
Rats, prairie dogs, livestock, rodents, wild animals, etc. are reservoirs for Yersinia spp. The bacteria is an example of what type of organim?
Zoonotic organism
What is the most virulent type of H. influenzae?
H. influenzae type B
What virulence factors are shared by the Enterbacteriaceae family?
LPS membrane, capsules, phase variation of antigens, adhesins, exotoxins, Type III secretion systems (delivers virulence factors into host cell), siderophores, serum resistane (inhibit complement-mediated killing), antimicrobial resistance
What types of E. coli are most commonly seen in developing countries?
Enteroinvasive E. coli (EIEC), Eneterpathogenic E. coli (EPEC), Eneteroaggregative E. coli (EAggEC)
Watery diarrhea is associated with infection by which Vibrio spp.?
V. cholera or V. parahaemolyticus
V. cholera infection may include mucus within the watery diarrhea (“rice water stool”)
What are the three types of plagues and their associated symptoms?
Bubonic plague - fever, bacteremia, bubos (swelling of lymph nodes)
Septicemic plague - fever, shock, black skin
Pueumonic plague - fever, malaise, pulmonary symptoms
What type of agar is required for Haemophilis spp. growth?
Chocolate agar
What virulence factors are associated with Shigella?
Type III secretion system, Shiga toxin, enterotoxins, intracellular movement via actin rearrangement, low infectionous dose
C. fetus is a uncommon and opportunistic . Who is most at risk for infection?
Immunocomprimised and elderly
Gastritis, peptic or dueodenal ulcers, gastric adenocarcinoma, and MALT lymphoma are all associated with infection by what G- bacteria?
H. pylori
Ulcers are most common. Gastric adenocarcinoma is less common.
What differentiates pathogenic and nonpathogenic species of Haemophilus? Where are non-pathogenic species found?
Nonpathogenic species are non-encapsulated and are normal flora of the upper respiratory tract
What are the medically significant Klebsiella spp.?
K. pneumoniae, K. granulomatis
What is the difference between chocolate agar and blood agar?
Chocolate agar contains lysed RBCs for those bacteria that lack hemolysin ability.
What virulence factors are associated with Bordatella pertusis?
Adhesions for attachment to cilia, trachela cytotoxin, dermonecrotic toxin, adenylate cyclase toxin, pertussis toxin
What are the virulence factors of C. fetus?
Heat-stable, capsule-like protein, inhibits complement binding and complement-mediated killing
What are the general characteristics of Klebsiella spp.?
Non-motile, lactose fementing, capsule, mucoid colonies, antibiotic resistance
What diseases are associated with K. pneumoniae infection?
UTI, bacteremia, pneumonia (typically in compromised hosts)
What agar is needed for Camplybacter growth?
CAMPY agar
What are the morpholocial and biochemical characteristics of Helicobacter pylori?
Sprial rod, motile, urease positive, catalase poisitive, oxidase positive, microaerophilic, LPS membrane
What characteristics are associagted with Shigella spp.?
Non-motile, non-lactose fermenting, does not produce H2S
What virulence factors are associated with P. aeruginosa?
Capsule, antibiotic resistance, adhesins, exotoxin A, pigaments, elastases, phospholipase C, exyenzymes S & T
What are the four medically signifcant Shigella species?
S. sonnei
S. flexneri
S. boydii
S. dysenteriae
What clinical diserases are associated with E. coli infection?
UTI, gastroenteritis, sepsis & septic shock, neonatal meningitis
What cliincal diseases are associated with P. aeruginosa?
Pulmonary infections, infection of burns, hot tub folliculitis, UTIs, external otitis, eye infections after trauma, bacteremia, endocarditis
What characteristics are shared by all genera in the Enterobacteriaceae family?
Glucose fermenting, oxidase negative, catalase positive, resistant to bile salts, normal intestinal flora in humans and animals
This is a collection of closely related bacterial species grouped together that often colonize the respiratory tract of patients with cystic fibrious.
Burkholderia cepacia complex
What are the virulence factors of Neisseria spp.?
- Pili for attachment
- Porins to prevent phagolysosomal fusion
- Opacity proteins for attachment (N. gonorrhoeae only)
- Iron acquiring proteins
- Lipooligosaccharide (LOS) membrane
- IgA protease
- Beta lactamase (N. gonorrhoeae only)
- Capsule (N. meningitidis only)
What diseases are associated with S. Typhimurium and S. Enteritidis infection?
Gastroenteritis caused by food borne outbreaks
What does the O antigen represent?
O side chain on LPS
What are the G- cocobacilli genera?
Haemophilus spp.
Bordatella spp.
What are the morphological and biochemical characteristics of Neisseria spp.?
Diplococci, aerobic non-fermenters, oxidase positive, catalase positive
N. gonorrheae - oxidizes glucose only
N. meningitidis - oxidizes flucose and maltose
What virulence factors are associated with H. pylori?
Flagella, urease, adhesins, vacuolating cytotoxin (induces apoptosis), cytotoxin-associated gene (CagA)
What are the general characteristics of Salmonella?
Non-lactose fermenting, motile, produces H2S
What diseases are associated with S. Typhy and S. Paratyphi infection?
Enteric fever through fecal/oral transmission
What are the characteristics of Bordatella pertusis?
Coccobacillus, strict aerobe, nonmoitle, capsule, human disease
This Vibrio species commonly causes wound infections that may progress to septicemia.
V. vulnificus
What are the characteristics of Yersinia spp.?
Lactose non-fermenting, can grow at cold temperatures, zoonotic organism
What are the medically releveant Salmonella species?
S. Typi, S. Paratypi, S. Typhimurium, S. Enterititdis