Colorado Antibiogram | Department of Public Health & Environment

Antibiogram Links
Includes 2016-2017 data.

Background
An antibiogram is a summary of the antibiotic susceptibility of bacteria cultured from clinical specimens, usually specific to a healthcare facility. Healthcare providers use antibiograms to guide choice of antibiotic therapy before a patient’s microbiology test results are available. Antimicrobial stewardship teams use antibiograms to identify opportunities for improving antibiotic use, such as the inappropriate use of broad-spectrum antibiotics or antibiotics associated with rising rates of resistance.

The Colorado Antibiogram is a report of data pooled from individual hospital, nursing home, and assisted living facility antibiograms. The objectives of the Colorado Antibiogram are to:

Be a publicly available tool for antibiotic stewardship,
Increase public knowledge of antibiotic resistance,
Inform allocation of resources to improve antibiotic use,
Demonstrate antibiotic resistance patterns by region.

The Colorado Department of Public Health and Environment (CDPHE) will use the Colorado Antibiogram to inform population-level antimicrobial stewardship strategy.

Methods
CDPHE requested antibiograms containing 2017 data from acute care hospitals and clinical laboratories in Colorado. Data were pooled by region. The number of susceptible isolates was divided by the number of isolates tested to yield the percent of organisms susceptible.

Of 105 hospitals and hospital laboratories contacted, 44 (42%) provided antibiograms. All were included the analysis. Of these, 35 (80%) provided data from 2017 alone. The remaining 20% of hospitals submitted antibiograms that included data from 2017 combined with data from 2016 or 2018. Fourteen (32%) hospital antibiograms were from the Denver region, 11 (25%) were from the northeast region, 7 (16%) were from the southeast region, and 12 (27%) were from the west region.

Twenty-two general acute care hospitals provided further information about their antibiograms. Seventeen (77%) antibiograms included combined inpatient and outpatient data, and 18 (82%) included combined adult and pediatric data.

These hospitals were also asked about adherence to Clinical and Laboratory Standards Institute (CLSI) guidelines for creation of antibiograms (CLSI. M39-A4 2014): 12 (55%) included diagnostic specimens only, 13 (59%) included results for the first isolate per patient only, 15 (68%) included results for routinely tested antibiotics only, and 21 (95%) included only final, verified results.

CDPHE also received antibiograms from 216 skilled nursing facilities and 93 assisted living facilities from the Denver, northeast, and southeast regions representing data collected January 1, 2017-December 31, 2017 by a single laboratory. The laboratory reported adherence to CLSI guidelines, including diagnostics specimens only, first isolates per patient only, routinely tested antibiotics only, and only final, verified results.

Guidance for use
The Colorado Antibiogram should be used in the context of other factors important to improving antibiotic use. Healthcare providers should choose antibiotics based on activity, proven effectiveness, potential for antibiotic resistance or adverse events, and clinical judgment. Antibiotic stewards should consider principles of antibiotic stewardship, including the appropriate use of broad-spectrum antibiotics, de-escalation of empiric antibiotic coverage to targeted therapy, and use of evidence-based dose, duration, and route of administration.

Limitations
The accuracy of the Colorado Antibiogram is limited by the variability in methods used to create facility-specific antibiograms. Clinical laboratories do not always follow CLSI guidelines (CLSI. M39-A4 2014). Inclusion of surveillance isolates, multiple isolates from the same patient, isolates selected for special testing, or isolates from other times may bias the findings. Laboratories may not use updated standards for determining antibiotic susceptibility (CLSI M100 2017). Observed differences in antibiotic susceptibility patterns between regions, counties, or care settings may be due to differences in bacterial or patient populations, testing, treatment, reporting, or infection prevention practices. There are no confidence intervals around antibiotic susceptibility estimates to allow for statistical comparisons between locations or care settings. Facility-level data, when available, will better represent facility-specific antibiotic susceptibility patterns.

Assessment of Use
In July 2019, CDPHE assessed the use of the first Colorado Antibiogram through a web-based survey of hospital antimicrobial stewardship teams and nursing home infection prevention teams. There were 57 respondents from 31 hospitals and 26 nursing facilities. Fifty-two percent of respondents from hospitals and 35% of respondents from nursing facilities reported accessing the Colorado Antibiogram. Most respondents found the Colorado Antibiogram easy to use and recognized the limitations of the data. Common uses included identification of regional trends in pathogen susceptibility, antibiotic stewardship program planning, and as a reference for creating a facility-specific antibiogram. Most respondents indicated that they would like to see the Colorado Antibiogram updated annually. The Colorado Antibiogram appears to be a useful tool for antimicrobial stewardship. CDPHE is currently evaluating ways to improve the efficiency of production, especially data collection and entry, in order to produce future editions of the Colorado Antibiogram in a timelier manner.

2016 Data
2016 Colorado Antibiogram