A complete and multifaceted overview of antibiotic use and infection diagnosis in the intensive care unit: results from a prospective four-year registration

Abstract

Background: Preparing an antibiotic stewardship program requires detailed information on overall antibiotic use, prescription indication and ecology. However, longitudinal data of this kind are scarce. Computerization of the patient chart has offered the potential to collect complete data of high resolution. To gain insight in our global antibiotic use, we aimed to explore antibiotic prescription in our intensive care unit (ICU) from various angles over a prolonged time period.

Methods: We studied all adult patients admitted to Ghent University Hospital ICU from 1 January 2013 until 31 December 2016. Antibiotic prescription data were prospectively merged with diagnostic (suspected focus, severity and probability of infection at the time of prescription, or prophylaxis) and microbiology data by ICU physicians during daily workflow through dedicated software. Definite focus of infection and probability of infection (classified as high/moderate/low) were reassessed by dedicated ICU physicians at patient discharge.

Results: During the study period, 8763 patients were admitted and overall antibiotic consumption amounted to 1232 days of therapy (DOT)/1000 patient days. Antibacterial DOT (84% of total DOT) were linked with infection in 80%; the predominant foci were the respiratory tract (49%) and the abdomen (19%). A microbial cause was identified in 56% (3169/5686). Moderate/low probability infections accounted for 42% of antibacterial DOT prescribed for respiratory tract infections; for abdominal infections, this figure was 15%. The median treatment duration of moderate/low probability respiratory infections was 4 days (IQR 3-7). Antifungal DOT (16% of total DOT) were linked with infection in 47% of total antifungal DOT. Antifungal prophylaxis was primarily administered in the surgical ICU (76%), with a median duration of 4 DOT (IQR 2-9).

Conclusions: By prospectively combining antibiotic, microbiology and clinical data we were able to construct a longitudinal, multifaceted dataset on antibiotic use and infection diagnosis. A complete overview of this kind may allow the identification of antibiotic prescription patterns that require future antibiotic stewardship attention.

Keywords: Antibiotic stewardship; Electronic surveillance; Infection; Intensive care unit; Longitudinal surveillance.

Fig. 1

Antibiotic exposure per ICU episode. ab, antibiotic; ICU, intensive care unit; LOS, length of stay

Fig. 2

Bacterial and fungal infection focus. a Focus of bacterial infections (n = 5686); infection probability was classified as low, moderate or high in 14%, 27% and 59% of the bacterial infections, respectively; CLABSI, central-line-associated bloodstream infection. CLABSI incidence was 3.8/1000 catheter days. Crude ICU mortality rate in patients with CLABSI was 11.4%. b Focus of fungal infections (n = 520); infection probability was classified as low, moderate or high in 12%, 17% and 71% of the fungal infections, respectively; °presence of yeast in a normally sterile body site combined with clinical signs of infection; *fungal infection considered clinically likely by treating physician in the absence of yeast in a normally sterile body site; ^mucocutaneous candidiasis, candidiasis of the genitourinary tract, extra-pulmonary Aspergillus infection, invasive non-Aspergillus mold infection. c Bacterial respiratory infection (n = 2779); °bacterial pneumonia following macroaspiration; *tracheobronchitis criteria include fever, purulent tracheobronchial secretions, isolation of a respiratory pathogen of a good quality lower respiratory tract sample, no radiographic signs of new pneumonia. d Bacterial abdominal infection (n = 1094)

Fig. 3

Pathogens linked to bacterial respiratory and abdominal infections. a Pathogens linked to bacterial respiratory infection (n = 1828); Enterobacteriaceae = Citrobacter spp., Enterobacter spp., Escherichia coli, Hafnia spp., Klebsiella spp., Morganella spp., Proteus spp., Providencia spp., Serratia spp. Non-fermenting Gram-negative bacilli = Achromobacter spp., Acinetobacter spp., Stenotrophomonas spp., Pseudomonas spp., other non-fermenting Gram-negative bacilli. Streptococcus spp. = Streptococcus pneumoniae, Streptococcus pyogenes, Viridans streptococci, other streptococci. Other = culture results of referral hospital. Serologic diagnosis = Legionella pneumophila antigen, Streptococcus pneumoniae antigen. b Pathogens linked to bacterial abdominal infection (n = 1403); Enterobacteriaceae = Citrobacter spp., Enterobacter spp., Escherichia coli, Hafnia spp., Klebsiella spp., Morganella spp., Proteus spp., Providencia spp., Salmonella spp., Serratia spp., Yersinia spp. Enterococcus spp. = Enterococcus faecalis, Enterococcus faecium, other enterococci. Other = culture results of referral hospital. Non-fermenting Gram-negative bacilli = Achromobacter spp., Stenotrophomonas spp., Pseudomonas spp., other non-fermenting Gram-negative bacilli. Streptococcus spp. = Streptococcus pneumonia, Viridans streptococci, other streptococci. Staphylococcus spp. = Staphylococcus aureus, coagulase-negative staphylococci, other. Other Gram-negative = e.g. Bacteroides spp., Prevotella spp., Aeromonas spp., Campylobacter spp. Other Gram-positives = e.g. Clostridium spp., Bacillus spp.