The practice of infectious disease (ID) in the inpatient setting revolves around unsolicited consultation by the primary teams on what they feel is a difficult case. This longstanding practice assumes that the physician asking for the consult “knows what they do not know” and that they also know the data of when an ID consultation improves outcomes. One readily accepted exception to the unsolicited consultation rule is Staphylococcus aureus bacteremia based on numerous studies indicating improved mortality and fewer complications.1,2,3 Many of us who have worked in antimicrobial stewardship have long believed that the benefit of ID consultation in bacteremia extends to organisms beyond Staph aureus. In the absence of good data to mandate ID consultations this has resulted in a practice where stewardship directors would review positive blood culture lists and chat with treating physicians to see if there were questions regarding the management.
Recently published data by Shulder et al in gram-negative bacteremia may move the needle in favor of mandatory ID consultation for all positive blood cultures. In this large retrospective, observational trial conducted at 24 centers including academic centers, community hospitals, and VA medical centers, the investigators specifically examined cases of gram-negative bacteremia, including those caused by Enterobacterales as well as non-fermenters (Pseudomonas aeruginosa) and determined the presence of an infectious disease consultation (IDC) or not.4 The primary outcome was mortality at 30 days. Propensity scoring occurred to ensure matching of the two groups for confounding variables. To avoid immortal time bias, patients who died within 48 hours were excluded. Secondary outcomes included death at 90 days, 30-day readmission rates and 30-day recurrent bacteremia. The authors identified 4861 cases of gram-negative bacteremia of which 54% had an infectious disease consultation. A 40% reduction in mortality was observed with IDC vs no IDC at 30 days HR 0.60 (95%CI 0.47-0.77) and a 30% reduction in mortality was seen with IDC at 90 days HR 0.70 (95%CI 0.57-0.86). No difference was seen with infectious disease consultation in 30-day readmission rate or recurrent bacteremia.
What You Should Know
The data indicates a significant reduction in mortality at both 30 and 90 days when an ID consultation is involved, reinforcing the importance of specialized input in managing these infections.
The findings from the study align with previous research on other pathogens, such as Staphylococcus aureus, Enterococci, and Candida.
The data presented challenges the traditional practice of unsolicited ID consultation and proposes a shift towards a more systematic approach triggered by positive blood culture results.
The data in the current study is consistent with previous observational studies in Gram-negative bacteremia. In a study of 951 blood stream infections in China, of which 677 were caused by gram-negative organisms including E cloacae, E coli, K, pneumoniae, P aeruginosa and Acinetobacter spp, there was a 67% reduction in mortality with IDC vs. no IDC (HR, 0.331; p<0.05) 5. The group with Infectious Disease consultation was more likely to have received both appropriate empiric and definitive antibiotic therapy, source control of infection, and repeat blood cultures. Three groups specifically looked at Pseudomonas aeruginosa bloodstream infections and examined mortality by the presence or absence of an infectious disease consultation. 6,7,8 All 3 of the studies observed a statistically significant reduction in mortality with IDC with a 49% reduction in mortality observed in the largest of these studies by Ramanathan involving a review of 3256 patients.8
Additional data has been published on the value of infectious disease consultation in the setting of Enterococcal and Candida bloodstream infections. A meta-analysis was conducted in 13 studies involving 3582 patients with Candida bloodstream infections. A 59% reduction in mortality was observed in the 50% of subjects who received an infectious disease consultation RR 0.41 (95%CI 0.35-0.49). Those with an ID consultation were more likely to undergo an ophthalmologic exam, a cardiac echocardiogram and central, line removal.9 In a meta-analysis of three studies in Enterococcal bacteremia where a multi-variate analysis was performed to account for confounders, a 60% lower risk or mortality was observed with ID consultation.10
In conclusion, the large well-done study by Shulder and colleagues in gram-negative bactermia when added to the literature in bacteremia by other important pathogens suggests that we should be moving away from the concept of unsolicited Infectious Disease Consultation for bloodstream infections. Medical societies and hospitals should consider the practice of a positive blood culture result triggering an automatic ID consult.
References
- Saunderson RB, Gouliouris T, Nickerson EK, et al. Impact of routine bedside infectious disease consultation on clinical management and outcome of Staphylococcus aureus bacteraemia in adults. Clin Microbiol Infect. 2015 Aug;21(8):779-85. doi: 10.1016/j.cmi.2015.05.026.
- Bai AD, Showler A, Burry L, et al. Impact of Infectious Disease Consultation on Quality of Care, Mortality, and Length of Stay in Staphylococcus aureus Bacteremia: Results From a Large Multicenter Cohort Study. Clin Infect Dis. 2015 May 15;60(10):1451-61. doi: 10.1093/cid/civ120.
- Pérez-Rodríguez MT, Sousa A, López-Cortés LE, et al. Moving beyond unsolicited consultation: additional impact of a structured intervention on mortality in Staphylococcus aureus bacteraemia. J Antimicrob Chemother. 2019 Apr 1;74(4):1101-1107. doi: 10.1093/jac/dky556.
- Shulder S, Tamma PD, Fiawoo S, et al. Infectious Diseases Consultation Associated With Reduced Mortality in Gram-Negative Bacteremia. Clin Infect Dis. 2023 Nov 11;77(9):1234-1237. doi: 10.1093/cid/ciad383.
- Tang G, Huang L, Zong Z. Impact of Infectious Disease Consultation on Clinical Management and Outcome of Patients with Bloodstream Infection: a Retrospective Cohort Study. Sci Rep. 2017 Oct 10;7(1):12898. doi: 10.1038/s41598-017-13055-2.
- Chesdachai S, Kline S, Helmin D, Rajasingham R. The Effect of Infectious Diseases Consultation on Mortality in Hospitalized Patients With Methicillin-Resistant Staphylococcus aureus, Candida, and Pseudomonas Bloodstream Infections. Open Forum Infect Dis. 2020 Jan 11;7(1):ofaa010. doi: 10.1093/ofid/ofaa010. PMID: 31993451; PMCID: PMC6977941.
- Chiong F, Wasef MS, Liew KC, et al. The impact of infectious diseases consultation on the management and outcomes of Pseudomonas aeruginosa bacteraemia in adults: a retrospective cohort study. BMC Infect Dis. 2021 Jul 9;21(1):671. doi: 10.1186/s12879-021-06372-5.
- Ramanathan S, Albarillo FS, Fitzpatrick MA, et al. Infectious Disease Consults of Pseudomonas aeruginosa Bloodstream Infection and Impact on Health Outcomes. Open Forum Infect Dis. 2022 Sep 9;9(9):ofac456. doi: 10.1093/ofid/ofac456.
- Kobayashi T, Marra AR, Schweizer ML, et al. Impact of Infectious Disease Consultation in Patients With Candidemia: A Retrospective Study, Systematic Literature Review, and Meta-analysis. Open Forum Infect Dis. 2020 Aug 3;7(9):ofaa270. doi: 10.1093/ofid/ofaa270.
- Tholany J, Kobayashi T, Marra AR, Schweizer ML, Samuelson RJ, Suzuki H. Impact of Infectious Diseases Consultation on the Outcome of Patients With Enterococcal Bacteremia: A Systematic Literature Review and Meta-analysis. Open Forum Infect Dis. 2022 Apr 12;9(7):ofac200. doi: 10.1093/ofid/ofac200.
