Examination 3: Gram negative bacilli, fermentation, antibiotics Flashcards
- Only _____ % of people with Helicobacter pylori develop a peptic ulcer
- Glucose can be _____ by Vibrio.
- 10 - 20%
- Fermented
- Inhibitors of cell wall synthesis kill bacteria by _____.
- Vibrio, Aeromonas, and Chromobacterium are/are not normal flora. What are their O2 requirements?
- inhibited production of murein/peptidoglycan layer
- Are not / Facultative anaerobes
This agar is buffered to prevent pH changes.
Complications of peptic ulcer disease
Mueller-Hinton agar
Hemorrhage (anemia)
Complications of peptic ulcer disease
Hemorrhage (anemia)
Burkholderia mallei causes _____ in horses.
Glanders
_____ is typically not used for Campylobacter
Serodiagnosis
Antibiotics for other spp of Vibrio (besides cholerae) _____.
are not standardized
The mechanism of this antibiotic is not known but it only works within the urinary tract.
Nitrofurantoin
Sulfonamides are prescribed as a treatment for _____.
UTIs
Oxidase testing of Vibrio should only be done _____.
off SBAP or one w/o a fermentable sugar
Synergistic
When the result of 2 drugs is greater than the response of them separately
If Kirby-Bauer plates are too thin, this results in _____.
(2 Factors)
Larger zones of inhibition
False susceptibility
If an organism is resistant to an antibiotic the treatment is considered to be _____.
Not effective.
Helicobacter pylori buffers its immediate vicinity from HCl by _____.
producing ammonia and CO2 from endogenous urea
Chloramphenicol, Erythromycin, and Sulfa drugs may be indicated for the treatment of _____ due to the development of resistance to tetracycline and doxycycline.
Vibrio cholerae
Two antibiotics of cell membrane function are
Polymyxin B
Colistin
The Schlichter test is also known as _____.
Serum bacteriocidal test
How are B mallei and pseudomallei differentiated?
Definitive ID is often done in reference labs with additional biochemical tests.
What is a contraindication for aminoglycoside regimens and what should the patient avoid?
Contraindicated for renal patients.
Patient should avoid the use of NSAIDs.
Oxidase negative non-fermentative GNB (2)
Acinetobacter, Stenotrophomonas
How would a pH increase affect aminoglycoside activity?
It would decrease tetracycline activity.
2nd most common GNF isolated in clinical labs
Acinetobacter spp
Antibiotics can inhibit _____ , _____ , or _____ synthesis.
Cell wall
Protein
DNA/RNA
Achromobacter and Chryseobacterium are MacConkey _____ and Oxidase _____.
Positive/Positive
Kirby-Bauer susceptibility testing cultures should ideally be performed when the culture is _____. If it is too old this leads the cultures to be _____.
24 hours old
Non-viable and can lead to false susceptibilities
Macrolides and Chloramphenicol are _____.
Polymixins are NSAs that are most effective against _____.
Bacteriostatic inhibitors of protein synthesis
G- bacteria
V/A/C preferred habitat
Water
Helicobacter is ideally recovered on what two media?
Chocolate
Brucella
Environmentally mediated resistance
Results from physical/chemical characteristics of the environment
Meliodosis is known to occur in what geographical locale
Southeast Asia
Enzymes that mediate resistance to Beta Lactams
(5)
Penicillinases
Cephalosporinases
ESBL’s
Cephamycinases
Carbapenemases
Gram stain Vibrio
G- bacteria, straight to slightly curved rods
Infections of Alcaligenes and Bordetella are found more commonly in _____.
Commercial ID methods of these two are _____.
Immunosuppressed
Limited
This antibiotic is effective against G+, G-, and intracellular bacterial pathogens
Tetracycline
The E-test is a form of _____ susceptibility testing.
Quantitative
Pseudomonas has a net _____ charge.
Negative
Non-fermentive G- bacilli typically _____ on MacConkey agar.
grow
Acinetobacter is MAC _____ and oxidase _____.
Positive, Negative
This antibiotic type binds precursors of cell wall synthesis.
Glycopeptides
Rat bite fever symptoms include _____ (3).
Lymphadenitis
Rash
Flu-like symptoms
Also: relapsing fever, chills, systemic illness such as arthritis, meningitis, liver and spleen disease
Most common method of bacterial resistance to penicillins
Beta-lactamase
What are 01 and 0139, hemolysins, cytotoxins, and pili?
Virulence factors of Vibrio cholerae
Enterobacteriacea is MAC _____ and oxidase _____.
Positive, Negative
How are Kirby Bauer results reported?
Only as susceptible, resistant, or intermediate – NOT diameters.
Where should disks not be placed when performing a Kirby-Bauer sensitivity test?
Towards the edges of the plate.
Is Burkholderia mucoid or non-mucoid?
Non-mucoid
Glycopeptides and Bacitracin are _____.
NSAs effective against G+ bacteria
Cholera patients present with this particular kind of stool.
Rice water
How should Kirby Bauer disk-diffusion plates be incubated?
(Temperature, O2 conditions, Position)
35 degrees C
CO2, if required
Inverted
Mueller-Hinton agar is _____ to prevent _____.
Buffered
pH change
Environmentally, where is Alcaligenes found?
Soil, Water
Helicobacter pylori possible routes of transmission
Oral/Oral
Fecal/Oral
What is MBC?
Minimal Bactericidal Concentration. Minimum [] at which the bacterial population is killed
The folic acid pathway produces _____.
(Besides folic acid)
Precursors for DNA synthesis.
What is important to know about NSAIDs
Should not be used with aminoglycosides.
Chryseobacterium can survive in _____ environments, especially moist environments where _____ is present.
Hospital environments
Chlorinated water
NSAs effective against G- bacteria
Polymixins
Streptobacillus moniliformis grows on _____ with _____ and _____.
SBAP
Increased CO2
Humid environment
In humans Glanders can cause _____ (3).
Localized, pulmonary, and bloodstream infections
How do inhibitors of protein synthesis interfere with normal cell function?
(3 ways)
- Interrupt initial formation of proteins.
- Interferes with accurate reading of mRNA code.
- Disrupts ribosomal-mRNA complex
What antibiotic should be monitored carefully in terms of bone marrow aplasia?
Chloramphenicol
VRSA emerged from the exchange of genetic material from _____ to _____.
VRE to MRSA
Most GNF are oxidase positive except _____ and _____.
Acinetobacter Stenotrophomonas
[Alcaligenes / Bordetella] does not grow well.
Pick one of the two.
Bordetella
P aeruginosa has a _____ flagella
Monotrichous polar
Susceptibility testing for Campylobacter is typically not _____.
Standardized
Metronidazole is an inhibitor of _____.
DNA/RNA synthesis.
Mueller-Hinton agar supports the growth of _____.
Most frequent isolates
Kingella spp. (2)
K. kingae and K. denitrificans
When would an MIC be an appropriate test?
In use of penicillins or cephalosporins for S. pneumoniae treatments.
This DNA/RNA synthesis inhibitor leads to the quick development of resistance and is therefore usually used in combination with other antibiotics.
Rifampin
Streptobacillus monoliformis can cause _____ fever and _____ fever.
Rate bite fever
Haverhill fever.
Naladixic acid is the precursor to the BSA _____.
Fluoroquinolones.
Genetic mutation, gene transfer from one organism to another, or both, can lead to _____.
Microbial Mediated Resistance
This media, when uninoculated is green.
Hugh Leifson media
These are less toxic and more effective in humans
Synthetic antimicrobials
Alcaligenes and Bordetella are not _____ utilizers.
Bordetella bronchioseptica is NOT normal flora of _____.
Humans
Glucose
Campylobacter is not typically associated with _____.
Outbreaks
This agar is not antagonistic towards antibiotic activity.
Mueller-Hinton agar
Pyomelanin color
Brown
What should the MT do prior to plating Kirby-Bauer inoculum?
Press (formerly) sterile swab against one side of tube to remove excess fluid from it.
Cholera is a _____ disease.
Toxin-mediated
Bartonella quintana is the causative agent of _____.
Trench fever (historically)
Does Burkholderia (Pseudomonas) mallei affect humans?
Rarely
Pyocyanin
Blue green pigment on SBAP. Only produced by P aeruginosa. 4% don’t produce pyocyanin.
Acinetobacter spp. is _____ flora
possibly normal
Macrolides only affect _____
Gram-positive organisms
15 Minutes before next dose
30 minutes after dose
When a trough specimen is taken for the Schlichter test.
When a peak specimen is taken for the Schlichter test.
Largest group of antibiotics
Beta lactams
_____ screening method of sputum samples factors in SEC’s per low-power field and Neutrophils per high power field.
Bartlett’s
Campylobacter motility
Darting motility on wet prep
Lysed blood and tissues are the usual specimen for this organism. Grows on fresh chocolate agar (NOT BAP, NOT MacConkey). Requires prolonged incubation with CO2 (2 weeks). Requires high humidity
Bartonella spp.
Clinical Resistance
Drug is no longer effective for clinical use
against the organism.
This is determined by susceptibility testing.
Haverhill fever has more pronounced _____ than rat bite fever.
GI symptoms
Acitinobacillus, Aggregatibacter, Kingella, Cardiobacterium, Capnocytophaga
The above are considered to be of _____ virulence.
Low
Kirby-Bauer plates should be checked/measured after _____.
16-18 hours
When is a trough specimen taken for the Schlichter test?
When is the peak specimen taken for the Schlichter test?
15 Minutes before next dose
30 minutes after dose
Cary-Blair medium is necessary for _____.
Vibro spp.
Morphology of peptic ulcers
Shallow, oval, erosions on the mucosal surface
Pseudomonas and Burkholderia are MAC _____ and Oxidase _____.
Positive/Positive
Vibrio vulnificans does not spread _____. What is another Gram-negative organism that does not spread in this way?
From person to person
Burkholderia mallei
What is the mechanism of action of Sulfonamides?
Competitive inhibition of enzymes involved in folic acid synthesis
Gastritis and peptic ulcers might be indicative of _____.
Helicobacter pylori
Pyocyanin
Blue pigment that produces reactive O2 species causing tissue damage
Stenotrophomonas maltophila is the _____ most common GNF isolated clinically
3rd
Involved in nosocomial and opportunistic infections
Stenotrophomonas maltophila
Moraxella and elongated Neisseria are MacConkey _____ and Oxidase _____.
Negative/Positive
Small, curved, motile gram-negative bacilli
Prefer microaerobic (5-10% O2) environments
Campylobacter
Arcobacter
Newer, safer agents have minimized the use of this antibiotic due to its toxicity.
Chloramphenicol.
Polymixins are produced by _____.
Paenibacillus polymyxa
Aminoglycosides, macrolides, chloramphenicols, and tetracyclines are _____.
Four types of protein synthesis inhibitors.
Kirby-Bauer plates should be incubated at _____.
35 degrees C
Inverted to avoid excess moisture from collecting on agar surface
The preferred media for Helicobacter pylori is _____ agar with _____ % O2.
Temperature of incubation is _____ and incubation may take _____.
Chocolate
5-10%
35-37 C
1 Week
Mueller-Hinton agar is used in _____.
Kirby-Bauer susceptibility testing
Aminoglycosides are bacter(iostatic/cidal). This antibiotic’s dosage is monitored using _____.
Bacteriocidal
Peak and trough values
These can better withstand beta-lactamases
Cephalosporins
Acitinobacillus, Aggregatibacter, Kingella, Cardiobacterium, Capnocytophaga
Morphologically the above are _____.
(Microscopically)
Gram negative bacilli-coccobacilli
Other species of Chryseobacterium/Elizabethkingia may be varable in terms of their _____ and _____ reactions.
MacConkey and Oxidase
NSAs effective against G+ bacteria
Glycopeptides Bacitracin
Francisella tularensis is the causative agent of _____, which is characterized by the patient having _____.
This is optimally recovered on media with _____.
Tularemia. This disease is characterized by high fever (104 C).
Cysteine.
This spp causes Glanders in horses
Burkholderia mallei
What is the purpose of mucus?
Protects normal gastric epithelium from HCl
What are the four possible types of inhibitors of protein synthesis?
Aminoglycosides
Macrolides
Chloramphenicols
Tetracyclines
Secretes proteases and phospholipases that break down glycoprotein-lipid complexes in mucus
Helicobacter pylori
Gentamicin, Tobramycin, and Amikacin are _____.
Inhibitors of protein synthesis (aminoglycosides)
The ATB activity in a patient’s serum is determined by _____.
Serum bacteriocidal test (SBT)
Asaccharolytic organisms are _____.
Non glucose fermentating/oxidizing
Aminoglycosides are ineffective against _____.
Anaerobes
Incubation of glucose oxidizers
24 - 72 hours 22 -35 degrees C
ACV is oxidase _____.
Positive
Associated with bacteremia and infective endocarditis (5% of endocarditis cases due to these organisms)
HACEK
C in Campy-CVA
Cefoperazone
If pure culture is too heavy relative to the McFarland Standard, we will obtain results that are _____.
Falsely resistant
(More bacteria/area consume more antibiotic leading to smaller zones of inhibition. This makes them falsely resistant.)
Biological resistance
Changes in cell structure or physiology resulting in less susceptibility than previously observed
Cholera toxin is produced by these two serotypes
01 and 0139 of V cholerae
Helicobacter pylori gram staining characteristics
Curved, gram-negative rods
This can be fatal if it is in the bloodstream
Burkholderia (Pseudomonas) mallei
Glanders _____ be transmitted from horses to humans. Glanders ______ be transmitted from human to human.
Can Cannot
Stenotrophomonas maltophilia is _____ flora
Possibly normal
Campy-BAP contains the two antibiotics _____ and _____ in order to suppressthe growth of normal fecal flora.
vancomycin, trimethoprim
Chryseobacterium meningosepticum has been renamed to
Elizabethkingia meningoseptica
Chronic gastritis
Long-standing inflammation with mucosal atrophy, metaplasia, possibly dysplasia (malignant potential)
Warthin-Starry silver stain
Stain for biopsies of suspected Helicobacter pylori
Blue pigment that produces reactive oxygen species
Pyocyanin
This GNBC will not grow on MAC and is Oxidase+
Kingella
Aminoglycosides are not recommended with _____.
NSAIDs
Infections of Vibrio parahaemolyticus present with _____ diarrhea.
How many V haemolyticus cases are there per year in the US?
Watery
4500
What is Campy-CVA good for?
Arcobacter and Campylobacter recovery.
Inhibits protein synthesis in host cell
Exotoxin A
Pyocyanin is only produced by _____.
P. aeruginosa
The metabolism of glucose to pyruvate occurs through these three pathways.
EMP, ED, PP
Contraindicated for renal patients. Patient should also avoid the use of NSAIDs when taking this antibiotic regimen.
Aminoglycoside regimens
What are polymyxins derived from?
Paenibacillis (Bacillus) polymyxa
Three Burkholderia spp of significance
cepacia mallei pseudomallei
Contaminated oysters may contain this microorganism.
Vibrio vulnificans
Pseudomonas is MacConkey _____ and Oxidase _____.
Positive
Positive
Infection arises from cats harboring fleas. Causes bacteremia, enlarged lymph nodes, and pustule at site of infection.
Bartonella henselae
Cat scratch fever
Aeromonas lactose fermentation
LF and NLF
What are the preferred specimens for Vibrio vulnificans?
Wounds, blood, or stool (due to ingestion of seafood)
T/F All Pseudomonas aeruginosa produce pyocyanin
F – 4% do not produce pyocyanin
O2 requirements of glucose oxidizers
Obligate aerobes
Acinetobacter spp does not reduce _____ to _____.
Nitrates (NO3) to Nitrites (NO2)
Arcobacter and Campylobacter recovery is best done on _____ agar.
Campy-CVA
This inhibits intestinal flora in TCBS media
High pH (8.6)
Susceptibility testing is also referred to as _____.
Sensitivity testing.
Antibiogram
Guides physicians in selecting empiric therapy for future patients with the expectation of optimizing outcomes.
This organism’s normal habitat is gastric mucosa. It causes chronic infection and its transmission is poorly understood (oral/oral, fecal/oral)
Helicobacter pylori
PBPs are necessary for _____.
cell wall synthesis in G+ bacteria
Urease positive organism with corkscrew motility.
Helicobacter pylori
Some GNF are oxidizers of _____ and some are _____.
Glucose Asaccharolytic
Beta lactamase is produced by Gram _____ bacteria
Positive and negative
What does no reaction in both tubes indicate?
Unknown is asaccharolytic.
What causes meliodosis?
Burkholderia pseudomallei
Polymyxins are both _____.
bacteriostatic and bactericidal
Extended spectrum beta lactamases confer resistance to _____.
extended spectrum cephalosporins and monobactams
Death from cholera occurs due to _____.
Hypovolemic shock secondary to fluid loss. Dehydration.
Vibrio vulnificans is found in what two types of water?
Brackish, Seawater
This is used as a last resort against Pseudomonas aeruginosa
Inhibitors of cell membrane function
Acinetobacter is oxidase _____.
Negative
ACV all grow on _____, _____, and _____.
SBAP, Chocolate, and MAC
Environmentally, Burkholderia pseudomallei is found in _____.
Soil, rice paddies
Any process in which the O2 of a compound is increased.
Oxidation
Vibrio, Aeromonas, and Chromobacterium are all oxidase _____.
Positive
Chlamydia, Rickettsia, and Rickettsia-like organisms can be treated with what two antibiotics?
Tetracycline
Doxycycline
Inhibitors of protein synthesis are either _____ or _____.
Bactericidal
Bacteriostatic
Bacteriostatic agents are _____.
Inhibitory
In TCBS what inhibits G+ organisms?
Bile salts
These Vibrio serotypes have been involved in epidemics and pandemics
01 and 0139
What are nitroimidazoles?
NSA effective against anaerobic bacteria
Aminoglycosides are inhibitors of _____ synthesis.
Protein
How should ACV be incubated?
24 hours @ 35 degrees C in ambient CO2
MAC should only be incubated in ambient air
Etiological agents of gastritis
Alcohol, Smoking, Radiation
Chronic H. pylori infection
VISA and VRSA are susceptible to _____.
(3)
Daptomycin
Rifampin
Tetracycline
Associated with human bite wounds or closed fist wounds (abrasions from facial punches cause someone was throwin shaaaade)
Eikenella corrodens
Is Vibrio spread from person to person through casual contact?
Transmission through casual contact is not very likely. It is transmitted mostly through fecal-oral transmission
Surface carbohydrate that impedes phagocytosis
Alginate
What does the D-test indicate?
Presence of macrolide-inducible resistance to clindamycin produced by an inducible methylase (which alters the common ribosomal binding site for macrolides, clindamycin, and Group B Streptogrammins).
