1What is the colonial morphology of Bilophila wadsworthia?
Small, translucent colonies
2What is the Gram stain morphology of Bilophilia wadsworthia?
thin, small straight rods of uniform width with internal vacuoles
3What characteristics appearance does Bilophilia wadsworthia show on BBE agar?
Black centers in colonies (H2S+) - "Fish eyes"
4What are they key biochemical reactions of Bilophilia wadsworthia?
Bile = R
Catalase = very +
Indole = negative
Nitrate = +
Urea +
5What is the beta-lactamase status of Bilophila wadsworthia and what does it imply?
Beta-lactamase positive -> resistant to many beta-lactam agents
6Why is Bilophilia wadsworthia clinically important in appendicitis?
It is the third-most abundant anerobic bacterium found in patients with appendicitis
7What is the SPD results for Suturella wadsworthensis?
SPD: R S S
8What are the key identifying features of Leptotrichia buccalis?
Common mouth organism (may be in vaginal and intestinal tract)
Large gray, convoluted colonies
VERY THIN , pencil-shaped fusiform rod
One pointed end and one blunt end
SPD: RSS
9What are the SPD results for Dialister and Desulfovibrio?
SPD : R S R
10Where are anaerobic gram-positive cocci (anaGPC) normally found?
Normal flora of the mouth, upper respiratory tract, GI tract, and female genitourinary system
11Are anaerobic GPC usually isolated alone or in mixed infections?
usually part of polymicrobial infections (opportunistic pathogens)
12What is the general antibiotic pattern of anaerobic GPC?
Vancomycin = S
Colistin = R
13What is a simple and reliable test to differentiate aerobe vs anaerobe?
5 ug metronidazole disk
14How can a 5 ug metronidazole disk help differentiate organisms?
Zone >= 15 mm ------ likely anaerobic GPC
No zone ------ likely microaerophilic organism (e.g. streptococcus)
15What important trend has been seen recently with anaerobic GPC and metronidazole?
Increasing metronidazole resistance in some species (e.g., Peptostreptococcus spp., Anerococcus spp., Atopobium vaginae)
16What is the gram stain morphology of Peptostreptococcus anaerobius?
Coccobacilli in chains
17What is the kanamycin reaction of Peptostreptococcus anaerobius?
Kanamycin = S (at least 16 mm zonoe)
18What is the SPS (sodium polyanethol sulfonate) disk reaction for P. anaerobius?
(SPS >= 12 mm zone) = sensitive ; has to be at least 16 mm
19What infections is associated with P. anaerobius?
gingivitus and periodonitis
post partum endometritis
pelvic inflammatory disease
DISTINCT SWEET ODOR!!!
20What are the key identifying features of Peptoniphilus asaccharolyticus? and what can it look like?
Uniform cell size
Can occur in chains or clumps
Retains Gram stain poorly (can look like GNC)
Indole positive
Musty odor
;
can look like GNC
21What types of infections is Peptoniphilus asaccharolyticus usually associated with?
Polymicrobial anaerobic infections
Skin & soft tissue infections (especially diabetics)
Bone & joint infection
Surgical site infections
Can occasionally be isolated in pure culture
22What are the microscopic features of Parvimonas micra?
Small cells <= 0.6 microns; smallest GPC
23What is the size and morphology of Finegoldia magna?
Larghe cocci (larger than most anerobic GPC )
Looks like regular staff
24How common and pathogenic is Finegoldia magna?
Most frequently isolated anaerobic GPC
Most pathogenic
25What most common type of infection is Finegoldia magna implicated in?
Bone and joint infections (native and prosthetic joints)
26What is the microscopic appearance of anaerococcus?
appear in pairs, tetrads, irregular masses, or chains
27What are other anaGPC genus?
Peptococcus, Gallicola, Murdochiella, Atobium (ID'd through NGS) , Corpcoccus, Ruminococcus, Sarcina, Blautia
28What are the 3 anaerobic members of the genus Staphylococcus?
1. S. saccharolyticus
2. S aureus subsp anaerobius
3. S. epidermidis
29What is the most encountered Staphylococcus species in anaerobes?
Staphylococcus saccharolyticus
30Where are Veillonella species commonly isolated from?
Blood cultures
31What special characteristic may Veillonella exhibit under UV light?
May fluoresce red
32What is the nitrate reaction of Veillonella?
NO3 = VERY positive
33How does Clostrifium stain in older cultures?
Usually stains gram-positive early;
May appear gram-negative in older cultures: C. clostridioforme, C. innocuum, and C. ramosum almost always appear negative.
34Are most Clostridium species motiles or non-motile? and which species are non-motile?
Most strains are motile
Non-motile species include: C. perfringens, C. ramosum, C. innocuum
35Are Clostrifium species obligate anaerobes?
Most are obligate anaerobes, but oxygen tolerance varies widely
36Which Clostridium species are aerotolerant?
C. tertium
C. carnis
C. histolyticum
Occasionally C. perfringens may show scant growth on air.
37How do Clostridium and Bacillus differ in spore formation and catalase reaction?
Clostridium:
Forms spores anaerobically
Catalase negative
Bacillus:
Forms spores aerobically
Catalase positive
38What is the special potency disk (SPD) pattern for Clostridium species?
Vancomycin = S
Kanamycin = R
Colisitn = R
39What are the vancomycin exceptions in Clostridium?
Occasional C. ramosum = moderately susceptible to vancomycin
C. innocuum = resistant to vancomycin
40Where are Clostridium species found?
Widely distributed in teh environment
Part of normal human intestinal flora
41What are important virulence factors of Clostridium?
Clostridial toxins
42Are most Clostridium infections endogenous or exogenous?
Most infections are endogenous in origins
43Which Clostridium species causes food poisoning?
Exogeneous: C. perfringens
44Which Clostridium species causes tetanus?
C. tetani
45Which Clostridium species causes botulism?
C. botulinum
46Which Clostridium species is associated with soft tissue infections in injecting drug users?
C. novyi (Type A)
47What is C. difficile a major cause of?
Antibiotic-associated diarrhea;
Pseudomembranous colitis
48How do broad-spectrum antibiotics lead to C. difficile infection?
They remove the competitive barrier of normal flow
Allow C. difficile to grow and produce toxins
Cause antibiotic-associated colitis
49How severe can C. difficile disease become?
Ranges from mild diarrhea to overwhelming pseudomembranous colitis
Can be fatal
50What odor is associated with C. difficile?
Horse stable odor (para-cresol)
51What selective medium is used for C. difficile culture?
Cycloserine cefoxitin fructose agar (CCFA)
52What do C. difficile colonies look like on CCFA?
Yellow "ground glass" colonies
Fluoresce chartresuse
53Why is culture alone not sufficient to diagnose C difficile infection?
May misdiagnose antibiotic-associated diarrhea caused by other agents
Stool samples must also be assayed for C. difficile toxins.
54If GDH immunoassay and toxin assay are inconclusive, what should be done?
Perform nucleic acid testing (NAAT/PCR)
55Does a positive nucleis acid test automatically indicate C. difficile disease?
No, it may indicate colonization only
Must correlate with patient's signs and symptoms
56What is asympotomatic colonization?
Patient's stool tests positive for C. difficile and/or toxins (A and/or B)
BUT no clinical symptoms are present
57When is CDI (C. difficile infection) present?
Patient tests positive for toxigenic C difficile AND clinical sympotoms of infection are present.
58Which is more common: aympotomatic colonization or CDI?
Asymptomatic colonization is more common
59Should asympotomatic coloization usually be treated?
No, in most cases it should not be treated
60What is the gram stain morphology for Clostridium perfringens?
Boxcar-shaped
Large Gram-positive rods
Spores rarely seen
61What hemolysis pattern does C. perfringens produces on blood agar?
Double zone of beta-hemolysis
62What does C. perfringens produce in liquid media?
abundant gas
63What is the CAMP reaction of C. perfringens?
Reverse CAMP test positive
64What is the major exotoxin of C. perfrigens? and what does it do?
Alpha toxins (lecithinase) ; produces complete hemolysis of blood agar plate
65What infection si C. perfringens responsible for?
gas gangrene, food poisoning.
66What do toxins of C. perfringens do to muscle cells?
Kill human muscle cells
Cause necrosis (myonecrosis)
67Why is C. perfringens called "gas gangrene" ?
Organism releases gas in infected tissue
68Why is botulinum toxin clinically significant?
It is the most lethal poison known
Even a minute amount can be fatal
Considered a potential bioterrorism agent
69How many toxin serotypes of botulinum exist? and which toxin serotypes cause botulism in humans?
Seven serotypes: A-G;
A, B, and E
70What causes food-borne botulism?
Ingestion of pre-froemd toxin
Home-canned foods (toxins A, B)
Preserved fish or seafood (e.g., salmon not well cooked)
Spores resist heat at 100oC (toxin E)
71What causes infant botulism?
Consumption of foods contaiminated with botulinum spores
6-10% of syrups or honeys
Neurotoxin produced in vivo.
72What should be done with suspected C. botulinum isolates or material?
Immediately refer to local or state Public Health laboratory.
73What is the only way to definitely distinguish and identify toxin production?
Toxin neutralization test
(Performed by LA County Public Health Department)
74What is the gram stain for Clostridium tentani?
GPR; "drumstick" or "tennis racket"
75What does tetanospasmin do in Clostridium tetani?
Prevents release of a nuetrotransmitter
Causes continuous muscular spasm leading to "lock jaw"
76How is C. tetani typically identified?
Based on clinical findings
77What characterizes the RIC group ? (Very Resistant Group) and what does that include?
Very resistant to antibiotics ;
Clostridium ramosum, C. innocuum, C. clostridioforme
78What type of spores does Clostridium septicum have?
sub-terminal spores
79What serious clinical association is seen with C. septicum bacteremia?
associated with malifnancies
Leukemia
Lymphoma
80What type of cancer is strongly assocaited with gas gangrene caused by C. septicum?
Colorectal cancer
Other bowel defects
81What is the mortality rate of C. septicum bacteremia?
60-100%
Must be reported to physician immediately
82Is Clostridium tertium aerotolerant or strict anaerobe?
Aerotolerant
83What antibiotic resistance is seen with C. tertium?
May be resistant to :
Metronidazole, Clindamycin, Cephalosporins
84Is C. novyi aerotolerant or strict anaerobe?
Strict obligate anaerobe
85What major female reproductive infection is associated with P. sordellii?
Gas gangrene of the uterus
86What situations is uterine infection associated with?
Illegal or self-induced abortions
Spontaneous abortion
Normal vaginal delivery
Cesarean section
Medically induced abortion
87What neonatal infection is associated with P. sordellii?
Infection of umbilical stump of newborn