MICROBIO GRAM-NEGATIVE

GRAM NEGATIVE DIAGRAM

Gram - dipplococci. Metabolize ___ and produce ___. Contain lipooligosaccharides (LOS) with strong endotoxin activity.

N gonorrhoeae

glucose

IgA proteases

Acid production: Maltose and Glucose

N. meningococci

No polysaccharide capsule

Gonococci

Polysaccharide capsule

Meningococci

No maltose acid detection

Gonococci

Maltose acid detection

Meningococci

Gonococci has no vaccine due to antigenic variation of ___

pilus proteins

Meningococci has a vaccine ( ___ vaccine available for at-risk individuals)

type B

Gonococci are ___ transmitted

s3xually or perin4tally

Meningococci is transmitted via ___

respiratory and oral secretions

Causes gonorrhea, septic arthritis, neonatal conjunctivitis ( ___ after birth), pelvic inflammatory disease (PID), and ___

Gonococci

2-5 days

Fitz-Hugh-Curtis syndrome

Causes meningococcemia with petechial hemorrhages and gangrene of toes, meningitis, ___ (adrenal insufficiency, fever, DIC, shock)

Meningococci

Waterhouse-Friderichsen syndrome

Gonococci is diagnosed with?

NAT (nucleic acid test)

Meningococci is diagnosed via?

culture-based tests or PCR (polymerase chain reaction)

prevention of gonococci

Condoms ↓ sexual transmission

erythromycin eye ointment prevents neonatal blindness

prevention of meningococci

Rifampicin, ciprofloxacin, or ceftriaxone prophylaxis in close contacts

treatment of gonococci

ceftriaxone (+ azithromycin or doxycycline, for possible chlamydial coinfection)

treatment of meningococci

ceftriaxone or penicillin G

Small Gram-negative (coccobacillary) rod. ___ transmission.

HAEMOPHILUS INFLUENZAE

Aerosol

most common cause of ___ (otitis media, conjunctivitis, bronchitis), as well as invasive infections, since the vaccine for ___ was introduced (Given between ___ of age)

HAEMOPHILUS INFLUENZAE

mucosal infections

capsular type b

2 and 18 months

Produces IgA protease. Culture on ___, which contains factors V (NAD) and X (hemin) for ___, can also be grown with ___, which provides factor V via ___.

HAEMOPHILUS INFLUENZAE

chocolate agar

growth

S aureus

RBC hemolysis

HaEMOPhilus causes

Epiglottitis (endoscopic appearance, can be "cherry red" in children; "thumb sign" on lateral neck X-ray B)

Meningitis

Otitis media

Pneumonia

The vaccine, type b capsular, contains ___ conjugated to ___ or other protein.

HAEMOPHILUS INFLUENZAE

polysaccharide (polyribosylribitol phosphate)

diphtheria toxoid

In H. influenzae, it does not cause the flu (the ___ does)

influenza virus

Treatment of H. influenzae

amoxicillin +/- clavulanate for mucosal infections

ceftriaxone for meningitis

rifampin prophylaxis for close contacts

BORDETELLA PERTUSSIS Virulence factors

pertussis toxin (disables Gi)

adenylate cyclase toxin (increases cAMP)

tracheal cytotoxin

Three clinical stages of B. pertussis

Catarrhal

Paroxysmal

Convalescent

in B. pertussis, Catarrhal causes? specifically?

low-grade fevers: Coryza

in B. pertussis, Paroxysmal causes?

intense cough followed by inspiratory "whoop" ("whooping cough"), posttussive vomiting

in B. pertussis, Convalescent causes?

gradual recovery from a chronic cough

B. pertussis is prevented by

Tdap (tetanus, diphtheria, acellular pertussis): infants & children younger than 7

Dtap: (diphtheria, tetanus, acellular pertussis): adolescents and adults (include during pregnancy)

___ may be mistaken for a viral infection due to ___ resulting from immune response

B. pertussis

lymphocytic infiltrate

Treatment of B. pertussis

macrolides; if allergic, use TMP-SMX

Gram-negative aerobic coccobacillus. Transmitted via ingestion of ___.

BRUCELLA

contaminated animal products (eg, unpasteurized milk)

BRUCELLA survives in ___ in the ___. Can form ___.

macrophages

reticuloendothelial system

non-caseating granulomas

Typically presents with undulant fever, night sweats, and arthralgia.

BRUCELLA

Treatment of BRUCELLA

doxycycline + rifampin or streptomycin

Gram-negative, strictly aerobic, oxidase-negative coccobacillus

ACINETOBACTER BAUMANNII

Commensal opportunist but increasingly associated with resistant hospital-acquired infections, especially in the ICU.

ACINETOBACTER BAUMANNII

Can cause ventilator-associated pneumonia and septicemia in immunocompromised patients.

ACINETOBACTER BAUMANNII

Gram-negative, ___ (with polar flagella), oxidase-positive, grows at ___

CAMPYLOBACTER JEJUNI

comma- or S-shaped

42°C

A major cause of bloody diarrhea, especially in children.

CAMPYLOBACTER JEJUNI

Fecal-oral transmission through person-to-person contact or via ingestion of undercooked contaminated poultry or meat, or unpasteurized milk.

CAMPYLOBACTER JEJUNI

CAMPYLOBACTER JEJUNI occurs with contact in?

infected animals (dogs, cats, pigs)

CAMPYLOBACTER JEJUNI is a common antecedent to

Guillain-Barré syndrome and reactive arthritis

Gram-negative curved rods

VIBRIO CHOLERAE

Curved, flagellated (motile), Gram-negative rod that is triple+: catalase +, oxidase +, and urease +

HELICOBACTER PYLORI test for diagnosis

urea breath test or fecal antigen test

Urease produces ___, creating an ___ environment, which helps H pylori survive in ___.

ammonia

alkaline

acidic mucosa

H pylori colonizes mainly the ___; causes ___ (especially duodenal).

antrum of the stomach

gastritis and peptic ulcers

Risk factor for peptic ulcer disease, gastric adenocarcinoma, and MALT lymphoma.

H pylori

The most common initial treatment of H pylori

triple therapy: - Amoxicillin (metronidazole if penicillin allergy) + Clarithromycin + Proton pump inhibitor; Antibiotics Cure Pylori.

macrolide resistance: Bismuth-based quadruple therapy

Gram-negative, indole-positive rod.

ESCHERICHIA COLI

E coli virulence factors

Fimbriae

K capsule

LPS endotoxin

E coli virulence factors: Fimbriae causes?

cystitis and pyelonephritis (P pili)

E coli virulence factors: K capsule causes?

pneumonia, neonatal meningitis

E coli virulence factors LPS endotoxin

septic shock

Strains in ESCHERICHIA COLI

Enteroinvasive E. coli (EIEC)

Enterotoxigenic E. coli (ETEC)

Enteropathogenic E. coli (EPEC)

Enterohemorrhagic E. coli (EHEC)

Microbe invades the intestinal mucosa and causes necrosis and inflammation

Enteroinvasive E. coli

Produces heat-labile and heat-stable enterotoxins. No inflammation or invasion.

Enterotoxigenic E. coli

No toxin produced. Adheres to apical surface, flattens villi, and prevents absorption.

Enteropathogenic E. coli

___ is the most common serotype in the US. Often transmitted via undercooked meat, raw leafy vegetables

Enterohemorrhagic E. coli

O157:H7

___ causes hemolytic-uremic syndrome: triad of anemia, thrombocytopenia, and acute kidney injury due to microthrombi forming on damaged endothelium → mechanical hemolysis (with schistocytes on peripheral blood smear), platelet consumption, and ↓ renal blood flow.

Enterohemorrhagic E. coli

Shiga-like toxin

Invasive; dysentery. Clinical manifestations similar to Shigella.

Enteroinvasive E. coli EIEC

Traveler’s diarrhea (watery)

Enterotoxigenic E. coli ETEC

E.coli that causes Diarrhea, usually in children

Enteropathogenic E. coli EPEC

Dysentery (toxin alone causes necrosis and inflammation).

Enterohemorrhagic E. coli EHEC

Does not ferment ___ (vs other E coli). Hemorrhagic, Hamburgers, Hemolytic-uremic syndrome.

Enterohemorrhagic E. coli EHEC

sorbitol

Gram-negative rod in ___ that causes ___ in alcoholics and diabetics when aspirated.

KLEBSIELLA

intestinal flora

lobar pneumonia

In ___, very ___ are caused by abundant polysaccharide capsules. ___ (blood/mucus).

KLEBSIELLA

mucoid colonies

Dark red "currant jelly” sputum

Also a cause of nosocomial UTIs. Associated with the evolution of ___

KLEBSIELLA

multidrug resistance (MDR)

ABCDE's of Klebsiella

● Aspiration pneumonia

● aBscess in lungs and liver

● "Currant jelly" sputum

● Diabetes

● EtOH abuse

aerobic, motile, catalase-positive, Gram-negative rod. Non-lactose fermenting. Oxidase positive.

Aeruginosa

Frequently found in water. Has a grape-like odor.

PSEUDOMONAS AERUGINOSA

associated with: Pneumonia, Sepsis, Ecthyma gangrenosum, UTIs, Diabetes, Osteomyelitis, Mucoid polysaccharide capsule, Otitis externa (swimmer's ear), Nosocomial infections (eg, catheters, equipment), Addicts (drug abusers), Skin infections (eg, hot tub folliculitis, wound infection in burn victims).

PSEUDOMONAS

In ___, ___ may contribute to chronic pneumonia in cystic fibrosis patients due to biofilm formation.

PSEUDOMONAS AERUGINOSA

Mucoid polysaccharide capsule

PSEUDOMONAS AERUGINOSA produces PEEP

Phospholipase C (degrades cell membranes)

Endotoxin (fever, shock)

Exotoxin A (inactivates EF-2)

Pigments: pyoverdine and pyocyanin (blue-green pigment; also generates reactive oxygen species).

Corneal ulcers/keratitis in contact lens wearers/minor eye trauma.

PSEUDOMONAS AERUGINOSA

rapidly progressive, necrotic cutaneous lesion caused by Pseudomonas bacteremia. Typically seen in immunocompromised patients.

Ecthyma gangrenosum

Treatment for Pseudomonas aeruginosa

CAMPFIRE

● Carbapenems

● Aminoglycosides

● Monobactams

● Polymyxins (eg, polymyxin B, colistin)

● Fluoroquinolones (eg, ciprofloxacin, levofloxacin)

● thIRd- and fourth- generation cephalosporins (eg, ceftazidime, cefepime)

● Extended-spectrum penicillins (eg, piperacillin, ticarcillin)

causes typhoid fever; carrier with gallbladder colonization

Salmonella typhi

Causes gastroenteritis by non-typhoidal salmonella

Salmonella spp. (except S. typhi)

no hematogenous spread, very small inoculum required, manifests tenesmus in GI

Shigella

what is the order of decreasing severity in Shigella first caused by ___

S dysenteriae

4F’s: Finger, Flies, Flood, Feces

Spiral-shaped bacteria A with axial filaments.

SPIROCHETES

SPIROCHETES Includes?

Borrelia (big size), Leptospira, and Treponema

In SPIROCHETES, only ___ can be visualized using ___ (___ stain) in ___ due to size.

Borrelia

aniline dyes

Wright or Giemsa

light microscopy

In ___, Treponema is visualized by ___ or ___ microscopy.

SPIROCHETES

dark-field microscopy

direct fluorescent antibody (DFA)

LYME DISEASE is caused by ___, which is transmitted by the ___ (also a vector for ___).

Borrelia burgdorferi

Ixodes deer tick

Anaplasma spp. and protozoa Babesia

In Lyme disease, The natural reservoir is the ___; ___ are essential to the tick life cycle but do not harbor ___.

mouse

deer

Borrelia

Common in the northeastern United States.

LYME DISEASE

In LYME DISEASE, Stage ___: ___: ___ (typical "bulls-eye" configuration B is pathognomonic but not always present), ___ symptoms.

1

early localized

erythema migrans

flu-like

In LYME DISEASE, Stage ___: ___: secondary lesions, carditis, AV block, facial nerve (Bell) palsy, migratory myalgias/transient arthritis.

2

early disseminated

In LYME DISEASE, Stage ___: ___: encephalopathy, chronic arthritis.

3

late disseminated

A Key Lyme pie to the FACE:

Facial nerve palsy (typically bilateral)

Arthritis

Cardiac block

Erythema migrans

Treatment of lyme disease

doxycycline (1st line)

amoxicillin: if severe illness, CNS signs, or heart block

ceftriaxone

Spirochete with ___ found in water contaminated with animal urine.

LEPTOSPIRA INTERROGANS

hook-shaped ends

flu-like symptoms, myalgias (classically of calves), jaundice, photophobia with conjunctival suffusion (erythema without exudate). Prevalent among ___ and in the ___ (eg, ___).

Leptospirosis

surfers

tropics

Hawaii

severe form with jaundice and azotemia from liver and kidney dysfunction, fever, hemorrhage, and anemia in LEPTOSPIRA INTERROGANS

Weil disease (icterohemorrhagic leptospirosis)