Infectious Disease Compendium

Klebsiella

Microbiology

Aerobic gram-negative rod, it is second to Escherichia coli as a pathogen in humans (Review). Includes

K. granulomatis, K. oxytoca, K. michiganensis, K. pneumoniae: K. p. subspecies. ozaenae, K. p. subspecies pneumoniae, K. p. subspecies rhinoscleromatis, K. quasipneumoniae: K. q. subspecies quasipneumoniae, K. q. subspecies similipneumoniae, K. grimontii, K. variicola.

Epidemiologic Risks

K. pneumoniae part of the human gut about 20% of the time and throughout the environment. Curiously, bloodstream infections are most common in the summer (PubMed). There has been one outbreak in a hospital due to transmission with hospital food, so there can be more than just the flavor of the dinner that is off (PubMed).

More often than not a nosocomial infection.

Syndromes

K. pneumonia is best known for lobar pneumonia but can cause other infections: cystitis, liver abscess in diabetics, etc.

There are hypervirulent/hyperviscous strains of K. pneumoniae (they are like snot on a plate and ate string test positive (PubMed)) that have a particular habit of causing eye and liver abscess. In Taiwan (and elsewhere) (PubMed) it is a cause of mono-microbial necrotizing fasciitis (Pubmed). There may be an association between liver abscesses and malignancy (PubMed). In China these hyperviscous strains now have a carbapenemase; it is only a matter of time before it spreads across the world. Our colon is Uber for bacteria.

K. oxytoca is associated with antibiotic-associated hemorrhagic colitis with Augmentin the most common culprit (PubMed)(PubMed).

K. rhinoscleromatis causes a chronic granulomatous infection (PubMed) of the upper airway, not uncommon (does this mean common?) in Eastern Europe, central Africa, South America, and Asia. More common in them what mate with their cousins.

K. variicola: humans and animals.

Klebsiella granulomatis: Granuloma Inguinale (Donovanosis) is a genital ulcerative disease.

Treatment

Given the increasing resistance of this organism to antibiotics, you have to know your local resistance patterns to give empiric therapy. Sorry. You actually have to know what you are doing. The most reliable agents are aminoglycosides, carbapenems, quinolones, and third-generation cephalosporins.

Be wary. ESBL (extended-spectrum beta-lactamase that hydrolyzes most beta-lactams (sparing only cephamycins and carbapenems) carrying Klebsiella are increasing in frequency and the only reliable antibiotic are carbapenems. Risks for ESBL include health care, urinary catheters, and prior antibiotics and if you choose wrong there is increased mortality (PubMed). If the mic for an ESBL to piperacillin/tazobactam is <= 2 the patient will do fine but if higher mic's expect death (PubMed). For bacteremia (or suspected) from and ESBL, carbapenems have less mortality than piperacillin/tazobactam (PubMed). Maybe (PubMed).

For E. coli or K. pneumoniae bloodstream infection with ceftriaxone resistance, INCREASED mortality with piperacillin-tazobactam compared to meropenem (PubMed).

If the organism is an ESBL, DO NOT use cefepime even if susceptible. Won't work as well as carbapenems (PubMed) and avoid piperacillin/tazobactam. Remember that sensitive in the lab does not always mean effective in the patient.

Use ceftibuten plus amoxicillin-clavulanic acid for po treatment of UTI with ESBL producing E. coli and K. pneumoniae (PubMed). Who knew there was actually a reason to give Augmentin?

There is also the New Delhi metallo-beta-lactamase, which inactivates all beta-lactams including carbapenems aka CRE (PubMed); often these are only sensitive to colistin and tigecycline. Ceftazidime-avibactam has a high failure rate with CRE and more resistance develops on therapy (PubMed), but other studies suggest it isn't all that bad (PubMed). And no surprise, CRE increases mortality (PubMed).

Ceftazidime-avibactam and aztreonam (PubMed)(PubMed) for some CRE, the so-called zone of hope (PubMed).

There is also meropenem/vaborbactam for some CRE strains, depending on the beta-lactamase and may be the best option (PubMed).

Tigecycline monotherapy is effective if the strains had an MIC ≤0.5 mg/L (PubMed).

And for CRI UTI (PubMed) and bloodstream infections (PubMed), there is Plazomicin.

CRE are perhaps more virulent with at least 1 in 3 dying as well as hard to kill (PubMed).

But if the patient is stable and has a TMP/Sulfa sensitive CRE in the urine, use it.

Notes

If there is an MDRO, ID consultation is associated with decreased mortality (PubMed). What a concept. Involving physicians who know what they are doing benefits patients.

How long will ESBL carriage last? At least 8 months in a third of patients (PubMed). However, another 12% acquired ESBL in the study. Can't do much about the ebb and flow of normal flora except wash your damn hands before touching patients.

Curious Cases

Relevant links to my Medscape blog

More Snot in the Wrong Place

Unlikely Occurrence

But Wait. There's More.

Diarrhea.

Last Update: 11/02/19.