GRAM - Flashcards
Diplococci, maltose & glucose oxidizer
Neissieria meningitidis
Diplococci, only glucose oxidizer
Neissieria gonorrhoeae
Diplococci, oxidase +
Moraxella catarrhalis
Bacillus, lactose fermenter/pink on MacConkey’s agar, fast fermenter
Klebsiella pneumoniae
Bacillus, lactose fermenter/pink on MacConkey’s agar, fast fermenter, indole +
Escherichia coli
Bacillus, lactose non-fermenter/white on MacConkey’s agar, oxidase -, produces H2S (black on TSI agar), urease -
Salmonella spp. (typhi and enteritidis)
Bacillus, lactose non-fermenter/white on MacConkey’s agar, oxidase -, produces H2S (black on TSI agar), urease +
Proteus mirabilis
Bacillus, lactose non-fermenter/white on MacConkey’s agar, oxidase -, does not produce H2S (not black on TSI agar)
Shigella sonnei/flexerni
Bacillus, lactose non-fermenter, oxidase +, glucose non-fermenter
Pseudomonas aeruginosa
Bacillus, lactose non-fermenter, oxidase +, glucose fermenter
Vibrio cholerae
Bacillus, lactose non-fermenter, motile at 25 C but not 37 C
Yersinia enterocolitica
Bacillus, lactose non-fermenter, bipolar staining
Yersinia pestis
Bacillus, curved small growth on Campy agar, urease +
Helicobacter pylori
Bacillus, curved small growth on Campy agar, urease -
Campylobacter jejuni
Bacillus, strict anaerobe
Bacteroides fragilis
Coccobacilli, factors V and X required
Haemophilus influenza B
Cocobacilli, growth on Bordet-Gengou medium
Bordetella pertussis
Neissieria meningitidis
Diplococci, maltose & glucose oxidizer
IgA protease LPS capsule (pt goes into shock after antibiotics because the bacterial cells lyse and LPS runs wild)
Respiratory and oral secretions
Vaccine
Rifampin for prophylaxis
Neissieria gonorrhoeae
Diplococci, only glucose oxidizer
IgA protease
NO LPS capsule
Grows on Thayer-Martin media, which contains vancomycin, polymixin, nystatin
Moraxella catarrhalis
Diplococci, oxidase +
IgA protease
No capsule
Ear and sinus infections
Klebsiella pneumoniae
Bacillus, lactose fermenter/pink on MacConkey’s agar, fast fermenter
Urease +
Capsule
Lobar pneumonia (esp. in alcoholics) -Must aspirate (normal gut flora) -Cause abscesses in LOWER lung -Horrible breath -Red currant jelly sputum UTI and would infections -More common -Diabetics and immunocompromised
Escherichia coli
Bacillus, lactose fermenter/pink on MacConkey’s agar, fast fermenter, indole +
Blue/Black metallic sheen on EMB agar
Fimbriae=attaches to uroepithelium and travels up–>cystitis and pyelonephritis
K capsule=enables it to be invasive
LPS capsule=shock
Salmonella enteritidis
Bacillus, lactose non-fermenter/white on MacConkey’s agar, oxidase -, produces H2S (black on TSI agar), urease -
Motile and disseminates (“swims like a salmon”)
Invades M cells of intestines: fever, headache, bloody, inflammatory, diarrhea
In sickle cell pts who get Salmonella, osteomyelitis is a common complication
Proteus mirabilis
Bacillus, lactose non-fermenter/white on MacConkey’s agar, oxidase -, produces H2S (black on TSI agar), urease +
***Swarming motility on agar
Urease positive–>stag horn calculi/struvite stone/stone shaped like renal calyx, which can also be a nidus for UTIs
Shigella sonnei (USA and Europe) Shigella flexerni (third world countries)
Bacillus, lactose non-fermenter–>white/yellow on MacConkey’s agar, oxidase -, does not produce H2S (not black on TSI agar)
Invades M cells of intestines
Non-motile, no flagella
Propel from cell to cell using actin polymerization (similar to, but not the same as Listeria)
Shiga toxin (similar to EHEC)=cleaves 60s subunit of rRNA and releases cytokines-->necrosis and inflammation of mucosa-->profuse bloody diarrhea, high fever, large & painful bowel movements, abdominal cramping, leukocytes in stool [shiga toxin is phage encoded transferred in lysogenic phage
Complications
- HUS (shiga toxin, much like EHEC)
- Reactive arthritis (Reiter’s syndrome)
- Seizures in children
Pseudomonas aeruginosa
Bacillus, lactose non-fermenter, oxidase +, glucose non-fermenter
Aerobic
Exotoxin A=similar to diphtheria toxin–>inactivates EF-2 via ADP ribosylation
Endotoxin=capsule causing fever and shock
Pyocin–>Gives blue-greeen pigment
Alginate=biofilm
Think “PSEUDO”
- Pneumonia
- Sepsis
- External otitis
- UTI
- Diabetic/Druggy Osteomyelitis
Tx ALWAYS w/ more than one antibiotic–>use strong gram neg=aminoglycoside + “antipseudomonals” (ticarcillin, pipercillin)
Vibrio cholerae
Bacillus, lactose non-fermenter, oxidase +, glucose fermenter, alkaline media
***Rice water diarrhea (profuse, watery diarrhea)
Cholera toxin=permanently activates Gs–>↑cAMP (cholera toxin encoded by lysogenic phage)
TCP (toxin coregulated pilus)=required for colonization
Yersinia enterocolitica
Bacillus, lactose non-fermenter, motile at 25 C but not 37 C
Day care diarrhea, puppy poop
Terminal ileitis: fever, RLQ pain, diarrhea (no diarrhea in appendicitis), mesenteric adenitis
Siderophilic
Very common in hemochromatosis pts
Yersinia pestis
Bacillus, lactose non-fermenter, bipolar staining
Flea bite
“The Plague”
- Fever, large painful lymph nodes in axilla or inguinal area, failure to respond to antibiotics
- Pneumonia
- Sepsis
- Can lead to DIC
Helicobacter pylori
Bacillus, curved small growth on Campy agar, urease +
CagA=inflammation and ulceration
VacA=damages epithelial cells
Causes most gastric and duodenal ulcers–>epigastric pain, belching, dyspepsia, nausea, melena
Causes acute and chronic gastritis
Associated with greater risk of stomach cancer
Diagnose w/ H2 breath test, esophageal pH test, and biopsy
Tx w/ 2 antibiotics (METRONIDAZOLE plus either tetracycline, amoxicillin, or clarithromycin) plus a “stomach soother” (Pepto-Bismol or PPI like omeprazole)
Campylobacter jejuni
Bacillus, curved small growth on Campy agar (***Seagull-shaped), urease -, oxidase +, grows at 42 C
Inflammatory diarrhea with mucus, pus, and WBC in stool
Associated w/ Guillan-Barre Syndrome
Bacteroides fragilis
Bacillus, strict anaerobe
Usually forms abcess
MC anaerobe in anaerobic peritoneal infections
Haemophilus influenza B
Coccobacilli, factors V and X required
***CHOCOLATE AGAR (contains factor V=NAD+ and factor X=hematin)
IgA protease
Capsule–>+Quellung reaction
Otitis media, pneumonia,meningitis
***EPIGLOTTITIS (respiratory stridor, hot potato voice, barking cough, fever, drooling)
Vaccine available (type B capsular polysaccharide attached to diphtheria toxoid)
Tx with Ceftriaxone
Prophylaxis w/ Rifampin
Bordetella pertussis
Cocobacilli, growth on Bordet-Gengou medium
***Whooping cough
Pertussis toxin=inhibitis Gi–>↑cAMP (this prevents lymphocytes from getting into the lymph nodes and start an immune reaction)
Grows on Bordet-Gengou (Potato) agar
Catarrhal stage=most infectious
-common cold symptoms
Paroxysmal stage=whooping cough
-↑severity–>can vomit or become cyanotic
UPEC
Uropathogenic E. coli (“U”: think–>URINARY)
Fimbriae (motile)
Cystitis/UTI (w/ no fever), pyelonephritis, or prostatits in men
EIEC
Enteroinvasive E. coli (“I” think–>INVASIVE or irritating)
mc due to poor sanitation/fecal matter in drinking water
Non-motile
Shiga-like toxin (similar to EHEC)=cleaves 60s subunit of rRNA and releases cytokines–>necrosis and inflammation of mucosa–>profuse bloody diarrhea, high fever, abdominal cramping, leukocytes in stool
[shiga toxin is phage encoded transferred in lysogenic phage)
Invades mucosa=dysentery=bloody, profuse diarrhea
(High fever, abdominal cramping, leukocytes in stool)
ETEC
Enterotoxigenic E. coli (“T” think–>TOXIC)
mc cause of diarrhea worldwide; Traveler’s/Troop diarrhea
Heat labile toxin=similar to cholera toxin–>↑cAMP–>secretory diarrhea
Heat stabile toxin–>↑cGMP–>secretory diarrhea
EPEC
Enteropathogenic E. coli (“P” think–>PEDIATRICS
No toxin
Intimin=adheres to intestinal mucosa–>causes actin in cells to deform causing flattening of villi–>malabsorption
May or may not have bloody diarrhea
EHEC
Enterohemorrhagic E. coli (“H” think–>HEMORRHAGIC)
***O157:H7 serotype from undercooked beef
Shiga-like toxin (similar to EIEC)=cleaves 60s subunit of rRNA and releases cytokines–>necrosis and inflammation of mucosa–>profuse bloody diarrhea, high fever, abdominal cramping, leukocytes in stool–>can cause HUS
[shiga toxin is phage encoded transferred in lysogenic phage)
DOES NOT FERMENT SORBITOL which distinguishes it from all other E. coli strains
Klebsiella granulomatosis
STD
Forms a nodule–>PAINLESS genital ulcer–>destruction of tissue
***No inguinal lymphadenopathy, in contrast to syphyllis
Donovan bodies in lymph nodes
Enterobacter cloacae
Bacillus, lactose fermenter/pink on MacConkey’s agar, fast fermenter
Nosocomial, multidrug resistant UTI bug
Normal gut flora
Citrobacter
Bacillus, lactose fermenter/pink on MacConkey’s agar, slow fermenter
uses CITRATE for carbon source
rare
Serratia Marcescens
Bacillus, lactose fermenter/pink on MacConkey’s agar, slow fermenter
Casein hydrolysis
Red pigment
R factor plasmid=contains numerous resistance genes
MC catheter-associated UTI
Salmonella typhi
Bacillus, lactose non-fermenter/white on MacConkey’s agar, oxidase -, produces H2S (black on TSI agar), urease -
Motile and disseminates (“swims like a salmon”)
“Typhoid fever”
- Fluctuating fever w/ bradycardia (Faget sign) and epistaxis
- Dicrotic pulse wave***
- Delirium (nervous fever) and rose spots
- Can have bloody diarrhea and hepatosplenomegaly
Vibrio vulnificus
***Raw oysters or swimming in infected waters
Vomiting, diarrhea, abdominal pain, and blistering dermatitis
Vibrio parahaemolyticus
***Raw oysters
Vomiting, diarrhea, abdominal pain
Legionella pneumophila
Bacillus, silver staining, aerobic
***Intracellular–>forms a Legionella containing vacuole used for site of replication and pathogenesis
Transmitted via infected waters (e.g. pool of water, AC units, aerosolizing water units)
Charcoal yeast extract culture, contains iron and cysteine
Legionella urine antigen test=diagnosis
Pontiac Fever
- Mild flu
- No pneumonia symptoms
- Healthy people