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.
Part of the human gut. 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.
The hyperviscous strains (they are like snot on a plate) have a particular habit of causing eye and liver abscess. In Taiwan (and elsewhere) (PubMed) it is a cause on mono-microbial necrotizing fasciitis (Pubmed). There may be an association between liver abscesses and malignancy (PubMed). In China these hyperviscous strains now have a carbepenemase; it is only a matter of time before it spreads across the world. Our colon is Uber for bacteria.
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.
Given 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 hydrolyse most b-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 MICs expect death (PubMed). For bacteremia (or suspected) from and ESBL, carbapenems have less mortality than piperacillin/tazobactam (PubMed). Maybe (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.
Ceftazadime-avibactam has a high failure rate with CRE with resistance common, although it may be better than the options (PubMed) and is useful for the KPC beta-lactamases, although resistance can occur on therapy.
There is also meropenem/vaborbactam for some strains, depending on the beta-lactamse.
CRE are perhaps more virulent with at least 1 in 3 dying as well as hard to kill (PubMed).
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 carraige 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.
Relevant links to my Medscape blog
Last Update: 04/28/18.