Colorado Antibiogram

2024 Antibiogram

Statewide Antibiogram for Gram Positive Bacteria in Hospitals Submitting Antimicrobial Resistance Data to NHSN–Colorado, 2023 (n=34 hospitals)

AMX, amoxicillin; AM, ampicillin; CM, clindamycin; DAP, daptomycin; E, erythromycin; LVX, levofloxacin; LZD, linezolid; NHSN, National Healthcare Safety Network; R, intrinsic resistance; %S, percent susceptible; SXT, trimethoprim-sulfamethoxazole; TE, tetracycline; VA, vancomycin. (Reference: CLSI M100 2024). 

Statewide Antibiogram for Gram Negative Bacteria in Hospitals Submitting Antimicrobial Resistance Data to NHSN–Colorado, 2023 (n=34 hospitals)

CIP, ciprofloxacin; CRO, ceftriaxone; CZ, cefazolin; FEP, cefepime; FM, nitrofurantoin; LVX, levofloxacin; MEM, meropenem; NHSN, National Healthcare Safety Network;  R, intrinsic resistance; %S, percent susceptible; SXT, trimethoprim-sulfamethoxazole; TZP, piperacillin-tazobactam.

*Citrobacter freundii complex, Enterobacter cloacae complex, Klebsiella aerogenes, Morganella morganii, Providencia spp., Serratia marcescens, and Yersinia enterocolitica may test susceptible to ceftriaxone, cefotaxime, ceftazidime, and ceftaroline, but these agents may be ineffective against these pathogens within a few days after initiation of therapy due to derepression of inducible AmpC β-lactamase.Therefore, isolates that are initially susceptible may become resistant. Testing subsequent isolates may be warranted if clinically indicated. (Reference: CLSI M100 2024). 

Guidance for use

The Colorado Antibiogram is a tool for antibiotic stewardship and is not intended for clinical use. It should be used in the context of other factors important to improving antibiotic use. 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. Healthcare providers should choose antibiotics based on activity, proven effectiveness, potential for antibiotic resistance or adverse events, and clinical judgment. If you need assistance reviewing the antibiogram tables, please reach out to cdphe_hai_ar@state.co.us.

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. CDPHE previously published antibiograms in 2016 and 2017 based on data pooled from individual facility antibiograms.

The 2024 Colorado Antibiogram is a report of pooled data submitted to the National Healthcare Safety Network (NHSN) Antimicrobial Resistance Option (AR option) by eligible facilities. The objectives of the Colorado Antibiogram are to:

• Provide a publicly available tool for antibiotic stewardship.
• Increase public knowledge of antibiotic resistance.
• Inform allocation of resources to improve antibiotic use.
• Inform population-level antimicrobial stewardship strategy. 

Methods

CDPHE reviewed 2023 antibiotic resistance data submitted to the NHSN Antimicrobial Resistance Option by Colorado hospitals. Hospitals were excluded if their Enterobacterales CLSI minimal inhibitory concentration breakpoints for carbapenems, third-generation cephalosporins, and monobactams were not updated in 2010 (Clinical and Laboratory Standards Institute (CLSI) M100 202417). The status of updates to antibiotic breakpoints was determined from self-reported responses to the 2023 NHSN Patient Safety Component Annual Hospital Survey. 

The antibiogram includes data from 34 hospitals, including 28 (82%) acute care hospitals, four (12%) critical access hospitals, and two (6%) inpatient rehabilitation facilities. Fifteen (44%) hospitals were from the Denver region, nine (26%) were from the northeast region, six (18%) were from the western slope region, and four (12%) were from the southeast region. Hospitals submitted data electronically from their laboratory information management systems according to 2023 NHSN Antimicrobial Resistance Option protocols [(CDC NHSN AUR Module)]. These indicate that the hospital should submit the first occurrence of each eligible organism isolated from blood or cerebrospinal fluid specimens within a 14 day period. For lower respiratory or urinary specimens, the hospital should submit the first occurrence of the first eligible organism isolated within a month. For a full list of pathogens and antimicrobials submitted to the NHSN AR option, visit CDC NHSN AUR Module.

We produced statewide antibiograms for gram positive and gram negative bacteria. Gram positive bacteria included: Enterococcus faecalis, Enterococcus faecium, S. aureus, and S. pneumoniae. Gram negative bacteria included E. coli, Klebsiella pneumoniae, Enterobacter cloacae complex, and Pseudomonas aeruginosa. To calculate the percent susceptible (%S) for each antibiotic-bacteria combination, we divided the pooled number of susceptible isolates by the number of isolates tested. Intrinsic resistance was indicated as “R” per CLSI guidelines (CLSI M100 202417). Combinations that were not available within the NHSN AR option and/or not reported by facilities were grayed out.

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-ED5 2022). Breakpoints were only evaluated for 2010 updates to Enterobacterales and carbapenems, third-generation cephalosporins, and monobactams. Other breakpoints were not evaluated. Laboratories may not use updated standards for determining antibiotic susceptibility (CLSI M100 2024). Data suppression in some laboratories using selective or cascade reporting may prevent submission of complete results and could inflate the resistance to secondary antibiotic treatment options. Not all hospitals in Colorado submit data to the NHSN AR option.