Sketchy Microbiology: Klebsiella Pneumoniae, Enterobacter Cloacae, Serratia Marcescens

Enterodactyl, Triserratiatops, and the Kleb-Tailed Dino — Klebsiella Pneumoniae, Enterobacter Cloacae, Serratia Marcescens

Red theme — Gram Negative

Milk Carton — (Enterobacterales species; aka Klebsiella Pneumoniae, Enterobacter Cloacae, Serratia Marcescens) Ferments lactose → turns MacConkey’s agar pink

What else do we know about the Enterobacterales species in general?

1. Facultative Anaerobe

2. Easy to culture in vitro

3. Like to colonize the L Intestine but infection only occurs when they reach other organs

What “pathogenic type” can be group Enterobacterales into?

1. Primary Pathogens vs. Opportunistic Pathogens

Hint: Where are they

In the hospital — (Enterobacterales species; aka Klebsiella Pneumoniae, Enterobacter Cloacae, Serratia Marcescens) are Nosocomial infections

Oxygen Mask — (Enterobacterales species; aka Klebsiella Pneumoniae, Enterobacter Cloacae, Serratia Marcescens) commonly cause Pneumonia

Urinary Bag — (Enterobacterales species; aka Klebsiella Pneumoniae, Enterobacter Cloacae, Serratia Marcescens) commonly cause UTI

Pills on the ground – (Enterobacterales species; aka Klebsiella Pneumoniae, Enterobacter Cloacae, Serratia Marcescens) have Multi Drug Resistant

Especially prone to 3rd Gen Cephalosporin and Carbapenem resistance!

Enterodactyl — Enterobacter (cloacae)

Hint: its flying

Flying — Enterobacter (cloacae) is Mobile

(Motility = Virulence Factor)

What else do we know about Enterobacter (cloacae)?

1. Common in long term hospital stay patients

   1. UTI, Ventilator-Associated, Line-Associated infections

2. Motility, Fimbriae, Sideophore = Virulence Factor

3. ampC cephalosporinase chromosome = 1st, 2nd Gen Cephalosporin resistance (sometimes even 3rd gen esistance)

Triceratops — Serratia (Marcescens)

Hint: Color / Climbing

Bright Red — Produced red pigment when cultured; called prodigiosin

Climbing — very mobile

What else do we knoew about Serratia (Marcescens)?

1. Opportunistic pathogen

   1. Skin, Pulmonary, CNS infections in Immunocompromised patients

2. Intrinsically resistant to ampicillin, macrolides, 1st gen cephalosporins

Kleb-Tailed Dino — Klebsiella (Pneumoniae)

Three A’s in the spikes – Alcoholics, Abscesses, Aspiration

Thick shell like scales — Klebsiella has a Polysaccharide Capsule

(Important Virulence factor)

Jar of currant jelly — Patients have current jelly-like red colored sputum

Jelly sticking klebsiella to the table — Kliebsiella is immotile

X-Ray — Klebsiella can cause cavatary lesion on patients’ lung lobe. Its TB-like

Ammonia spray bottle — Klebsiella is Urease positive

What do we know about Klebsiella pneumoniae’s virulence factors?

1. Capsule (Poly Saccharide) is most important

2. Sideophors

3. Fimbriae