Over-treatment of carbapenemase-producing Enterobacteriaceae.
OBJECTIVE
To describe the treatment and outcomes of patients with carbapenemase-producing Enterobacteriaceae and evaluate whether these cases represented active infection requiring antibiotic therapy or colonization.


METHODS
Adult inpatients with carbapenemase-producing Enterobacteriaceae were retrospectively evaluated. Cases were classified as colonization versus infection by 2 infectious diseases physicians. Multiple cultures that grew in the same patient within a 2-week period were evaluated as a single case.


RESULTS
A total of 42 cases among 35 patients were identified. The mean age of the cohort was 67.7 ± 13.7 y, mean APACHE II score was 17.9 ± 8.6, and 77% of patients were in the intensive care unit when the carbapenem-producing Enterobacteriaceae was isolated. Klebsiella pneumoniae (84%) was the predominant organism; urine (36%), tissue/wound/drainage (25%), and blood (20%) were the most common sites of collection. Though 43% of cases were classified as colonization, 56% of these cases were treated with antibiotics. Only 1 patient characterized as colonized subsequently developed infection, 29 days later. Among infected cases, colistin (55%), meropenem (41%), aminoglycosides (32%), and tigecycline (27%) were used for treatment, and combination antimicrobial therapy was common (55%). Clinical and microbiological success was higher in patients receiving combination therapy (83% vs 60%, p = 0.35). Colistin monotherapy was only successful in urinary infections. All-cause hospital mortality was 29%.


CONCLUSIONS
Nearly half of cases represented colonization, yet the majority were treated with broad-spectrum antibiotics. Determining infection versus colonization is a critical first step in managing patients with carbapenemase-producing Enterobacteriaceae. The risk of not treating apparent colonization appears low.
Department of Pharmacy, Orlando Health, Orlando, Florida, USA. deba.rihani@orlandohealth.com
Deba S
DS
Rihani
Mark R
MR
Wallace
Barry E
BE
Sieger
Robert A
RA
Waite
Marlena
M
Fox
Scott A
SA
Brown
C Andrew
CA
Deryke
D000368:Aged; D000369:Aged, 80 and over; D000617:Aminoglycosides / Q000494:pharmacology / Q000627:therapeutic use; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001426:Bacterial Proteins / Q000096:biosynthesis*; D003091:Colistin / Q000494:pharmacology / Q000627:therapeutic use; D024881:Drug Resistance, Bacterial; D004359:Drug Therapy, Combination; D004755:Enterobacteriaceae / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development* / Q000302:isolation & purification; D004756:Enterobacteriaceae Infections / Q000188:drug therapy* / Q000382:microbiology / Q000401:mortality; D005260:Female; D006801:Humans; D007710:Klebsiella Infections / Q000188:drug therapy / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development / Q000302:isolation & purification; D008297:Male; D000077731:Meropenem; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D013845:Thienamycins / Q000494:pharmacology / Q000627:therapeutic use; D016896:Treatment Outcome; D001618:beta-Lactamases / Q000096:biosynthesis*
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D013845:Thienamycins; D001618:beta-Lactamases; C063912:carbapenemase; D000077731:Meropenem; D003091:Colistin