KPC (Klebsiella pneumoniae Carbapenemases) producing bacteria has become a global threat, mainly due to the limited treatment options. This video gives a basic outline of the KPC enzyme and KPC-producing bacteria. You can view a video of this presentation here: https://youtu.be/vp7oyKyAq1s

1. K p C
KPC
Klebsiella pneumoniae Carbapenemases

2. Image credit: National Institute of Allergy and Infectious Diseases (NIAID)
human neutrophil
Carbapenem-resistant
Klebsiella pneumoniae

3. Cephalosporin
Penicillin
Aztreonam
β-Lactam Ring
β-Lactam
Antibiotics

4. e.g. Imipenem, Meropenem
Highly resistant to most β-Lactams including ESBLs
Broad-spectrum antibiotics
Last resort against ESBL–producing Enterobacteriaceae
& MDR Gram-negative bacilli

5. Active
Carbapenemases
Hydrolyze penicillins, cephalosporins,
monobactams, and carbapenems.
β-Lactamases
Inactive Image Source: Trends in Molecular Medicine

6. β-
1—4
Based on the substrate profile
Molecular Classification
Bush-Jacoby-Medeiros Classification
(BJM)
A—D
Based on the enzyme structure
Functional Classification
Ambler's Classification
Classification of beta-lactamases

7. BJM system
Major
subgroups
Ambler System Main attributes
Group 1 cephalosporinases – C (cephalosporinases)
Usually chromosomal; Resistance to all β-
lactams except carbapenems; Not inhibited
by clavulanate
Group 2 penicillinases 2a A (serine β-lactamases) Staphylococcal penicillinases
(clavulanicacidsusceptible) 2b A Broad-spectrum – TEM-1, TEM-2, SHV-1
2be A Extended-spectrum – TEM-3–160, SHV-2–101
2br A Inhibitor resistant TEM (IRT)
2c A Carbenicillin-hydrolyzing
2e A Cephalosporinases inhibited by clavulanate
2f A Carbapenemases inhibited by clavulanate
2d D(oxacillin-hydrolyzing) Cloxacillin-hydrolyzing (OXA)
Group 3 metallo-β-lactamase 3a B (metalloenzymes) Zinc-dependent carbapenemases
3b B
3c B
Group 4 Not classified Misc enzymes, most not yet sequenced
Perez, Federico, et al. "The continuing challenge of ESBLs." Curr opin pharm 7.5 (2007): 459-469.
KPC
Classification of beta-lactamases

8. KPC
Ambler Class A Serine β-lactamase, BMJ group 2f
First discovered in a Klebsiella pneumonia—North Carolina, US (1996) – KPC1
Klebsiella pneumoniae Carbapenemases
Later found in other genera of the Enterobacteriaceae family
Klebsiella oxytoca
Citrobacter freundii
Enterobacter aerogenes & E. Cloacae
Also in Pseudomonas aeruginosa & Acinetobacter baumannii
Escherichia coli
Serratia marcescens

9. KPC
16 variants (KPC-2 to KPC-17)—Most frequent KPC-2 and KPC-3
The most clinically significant enzymes of the class A carbapenemases
Klebsiella pneumoniae Carbapenemases
Clinical detection—often challenging
Hydrolyze β-lactams of all classes
Penicillins
All cephalosporins
Monobactams
Carbapenems
and β-lactamase inhibitors
Multidrug resistant—High mortality rates
Greatest potential for spread—Located on plasmids

10. KPC
Queenan, Anne Marie, and Karen Bush. "Carbapenemases: the versatile β-lactamases." Clinical microbiology reviews 20.3 (2007): 440-458.
Emergence
of
class A carbapenemases

11. KPC-1
Munoz-Price, L. Silvia, et al. "Clinical epidemiology of the global expansion of Klebsiella pneumoniae carbapenemases." The Lancet infectious diseases 13.9 (2013): 785-796.
KPC

12. Antibiotic sensitivity tests—inconsistent results
Carbapenemases alone doesn’t produce compete resistance.
Some KPC-producers are susceptible to carbapenems.
Variable levels of carbapenem resistance
Insufficient cell numbers
 Imipenem or Meropenem is not sensitive enough.
 Ertapenem —best so far
But ertapenem resistance by itself is not a marker for KPC expression.
Confirmatory tests are necessary. Modified Hodge Test
Molecular tools should become the gold standard.
Sensitivity varies with the substrate
KPC

13. E.coli ATCC 25922
suspension in
broth/saline
Diluted 1:10
Spread on a MHA plate
Place 10 μg antibiotic
disk in the center
Streak test organism(s)
Incubation overnight
at 35⁰C ± 2⁰ C
Susceptible to
carbapenems
KPC
E.coli ATCC 25922

14. Bora, Arijit, et al. "Incidence of metallo-beta-lactamase producing clinical isolates of Escherichia coli and Klebsiella pneumoniae in central Nepal." BMC research notes 7.1 (2014): 557.
Test organism secretes KPC and
inactivates the antibiotic.
E. Coli grows along the edges.
clover leaf-type
indentation
No E.coli
growthTest organism doesn’t secrete KPC.
Antibiotic remains active.
E. Coli growth inhibited.
KPC

15. • Perez, Federico, et al. "The continuing challenge of ESBLs." Current opinion in pharmacology 7.5 (2007): 459-469.
• Queenan, Anne Marie, and Karen Bush. "Carbapenemases: the versatile β-lactamases." Clinical microbiology reviews 20.3 (2007): 440-458.
• Robledo, Iraida E., Edna E. Aquino, and Guillermo J. Vázquez. "Detection of the KPC gene in Escherichia coli, Klebsiella pneumoniae, Pseudomonas
aeruginosa, and Acinetobacter baumannii during a PCR-based nosocomial surveillance study in Puerto Rico." Antimicrobial agents and
chemotherapy55.6 (2011): 2968-2970.
• Sacha, Paweł, et al. "The KPC type beta-lactamases: new enzymes that confer resistance to carbapenems in Gram-negative bacilli." Folia
Histochemica et Cytobiologica 47.4 (2009): 537-543.
• Wang, Dongguo, et al. "Phenotypic and Enzymatic Comparative Analysis of the KPC Variants, KPC-2 and Its Recently Discovered Variant KPC-15."
(2014): e111491.
• Walther-Rasmussen, Jan, and Niels Høiby. "Class A carbapenemases."Journal of antimicrobial chemotherapy 60.3 (2007): 470-482.
• Yigit, Hesna, et al. "Novel carbapenem-hydrolyzing β-lactamase, KPC-1, from a carbapenem-resistant strain of Klebsiella
pneumoniae." Antimicrobial agents and chemotherapy 45.4 (2001): 1151-1161.
• Yigit, Hesna, et al. "Novel carbapenem-hydrolyzing β-lactamase, KPC-1, from a carbapenem-resistant strain of Klebsiella
pneumoniae." Antimicrobial agents and chemotherapy 52.2 (2008): 809.