Abstract
BackgroundThe aim was to evaluate the value of organ-specific weighted incidence antibiogram (OSWIA) percentages for bacterial susceptibilities of Gram-negative bacteria (GNB) collected from intra-abdominal infections (IAIs) during SMART 2010–2014.MethodsWe retrospectively calculated the OSWIA percentages that would have been adequately covered by 12 common antimicrobials based on the bacterial compositions found in the appendix, peritoneum, colon, liver, gall bladder and pancreas.ResultsThe ESBL positive rates were 65.7% for Escherichia coli, 36.2% for Klebsiella pneumoniae, 42.9% for Proteus mirabilis and 33.1% for Klebsiella oxytoca. Escherichia coli were mainly found in the appendix (76.8%), but less so in the liver (32.4%). Klebsiella pneumoniae constituted 45.2% of the total liver pathogenic bacteria and 15.2–20.8% were found in 4 other organs, except the colon and appendix (< 10%). The percentages of Pseudomonas aeruginosa infections were higher in the gall bladder, intra-abdominal abscesses, pancreas and colon (10.2–13.2%) and least (5.4%) in the appendix. The susceptibilities of hospital acquired (HA) and community acquired (CA) IAI isolates from appendix, gall bladder and liver showed ≥80% susceptibilities to amikacin (AMK), imipenem (IPM), piperacillin-tazobactam (TZP) and ertapenem (ETP), while the susceptibility of isolates in abscesses and peritoneal fluid showed ≥80% susceptibility only to amikacin (AMK) and imipenem (IPM). In colon CA IAI isolates susceptibilities did not reach 80% for AMK and ETP, and in pancreatic IAIs susceptibilities of HA GNBs did not reach 80% to AMK, TZP and ETP, and CA GNBs to IMP and ETP. In addition, besides circa 80% susceptibility of HA and CA IAI isolates from appendix to cefoxitin (FOX), IAI isolates from all other organs had susceptibilities between 7.6 and 67.9% to all cephalosporins tested, 28.3–75.2% to fluoroquinolones and 7.6–51.0% to ampicillin-sulbactam (SAM), whether they were obtained from CA or HA infections.ConclusionThe calculated OSWIA susceptibilities were specific for different organs in abdominal infections.
Highlights
The aim was to evaluate the value of organ-specific weighted incidence antibiogram (OSWIA) percentages for bacterial susceptibilities of Gram-negative bacteria (GNB) collected from intra-abdominal infections (IAIs) during SMART 2010–2014
Other major pathogenic bacteria included 804 strains of P. aeruginosa (10.0%) and 558 strains of Acinetobacter baumannii (A. baumannii) (6.9%), which both belong to the non-fermentative bacteria group, as well as 410 strains of Enterobacter cloacae (E. cloacae) (5.1%)
Comparison of the pathogenic distribution of abdominal infections in different organs (2010–2014) In Figure 1, we show the pathogenic distribution of Gram-negative bacteria in some infected organs in the abdomen, including 2510 strains from the gall bladder (31.1%), 2078 strains from peritoneal fluid (25.8%), 1444 strains from abdominal abscesses (17.9%), and the remainder from the appendix (405 strains), colon (174 strains), liver (553 strains) and pancreas (256 strains), respectively
Summary
The aim was to evaluate the value of organ-specific weighted incidence antibiogram (OSWIA) percentages for bacterial susceptibilities of Gram-negative bacteria (GNB) collected from intra-abdominal infections (IAIs) during SMART 2010–2014. Herbert et al (2012) developed a novel method of displaying microbiology data to support early empirical antimicrobial treatments, which they termed the weighted-incidence syndromic combination antibiogram (WISCA). It classifies patients by syndrome and determines, for each patient with a given syndrome, whether a particular treatment regimen (one or more drugs) would have covered all the organisms recovered from their infections [8]. In the present study we created OSWIAs, which estimated the probability of organ specific isolates being susceptible to particular antibiotics
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