Presentation Number: P31 Author(s): Samuel Bouchillon, Robert Badal, Sibylle Lob, Meredith Hackel, Daryl Hoban, International Health Management Associates, Inc. Clinical

Author(s):
Samuel Bouchillon, Robert Badal, Sibylle Lob, Meredith Hackel, Daryl Hoban, International Health Management Associates, Inc.

Background: Nosocomial infections increase morbidity, mortality, length of stay and treatment cost. The SMART program tracks susceptibility of hospital- (HA) and community-associated (CA) intra-abdominal infection (IAI) Gram-negative pathogens (GNP) globally. This report summarizes susceptibility differences of HA IAI GNP between surgical and medical wards in the US.

Hypothesis: n/a

Methods: 23 labs in the US each collected up to 100 consecutive isolates yearly of aerobic GNP from IAI. From 2010 to 2012, 3,778 GNP were collected, of which 1,713 were from HA IAI. An IAI was defined as HA if cultured ≥48 hours post-admission. Antimicrobial susceptibility and extended-spectrum β-lactamase (ESBL) phenotypes were determined using the CLSI broth microdilution method.

Results: ESBL+ rates in surgical and medical wards were 7% and 11%, respectively, for E. coli (p>0.05, chi-square test) and 20% and 8% for K. pneumoniae (p<0.05). Prevalence and susceptibility (%S) of the top 3 species and of all GNP combined are shown below for selected drugs.
AMK=amikacin, FEP=cefepime, CTX=cefotaxime, FOX=cefoxitin, CAZ=ceftazidime, CRO=ceftriaxone, ETP=ertapenem, IMP=imipenem, LVX=levofloxacin, TZP=piperacillin-tazobactam, NB=no breakpoint.

Conclusions: On both surgical and medical wards, the top 3 species–E. coli, K. pneumoniae, and P. aeruginosa–made up almost 70% of IAI pathogens.
K. pneumoniae ESBL rates were significantly higher in surgical wards.
Overall susceptibility for all GNP combined was usually 3-6% lower in surgical wards. This decrease appears partly driven by both lower susceptibility and higher prevalence of typically less susceptible K. pneumoniae and P. aeruginosa in surgical wards.
Knowledge of the epidemiology of IAI pathogens, ESBL+ rates, and susceptibility patterns–not only by geographic location but also by patient location in the hospital–may be helpful for empiric therapy decisions for HA IAI.