The most recent National Heart, Lung, and Blood Institute (NHLBI) guidelines strongly recommend that providers treat acute chest syndrome with an intravenous cephalosporin and an oral macrolide antibiotic, As these guidelines are from 2014, is there any updated evidence to continue to support or refute this recommendation. Particularly, with the increased use of viral respiratory panels and increasing resistance, is a macrolide antibiotic still needed.

Comment by InpharmD Researcher

Since the 2014 NHLBI guideline, no newer guidelines have issued updated antibiotic recommendations for acute chest syndrome (ACS), and evidence supporting specific regimens remains largely observational. The 2019 Cochrane update identified no randomized controlled trials and concluded that the optimal antibiotic strategy remains uncertain. Observational studies from 2017 and 2025 generally support continued use of a parenteral cephalosporin plus a macrolide, with guideline-adherent therapy associated with lower readmission rates and, in some analyses, shorter hospital stays. A 2023 commentary noted that widespread use of multiplex polymerase chain reaction (PCR) assays provides a very high negative predictive value for atypical pathogens and may help identify patients in whom macrolide therapy is unnecessary; however, routine macrolide use remains common, driven by historical practice and possible immunomodulatory effects described in chronic pulmonary disease. A 2024 review continued to support empiric antibacterial coverage but did not specifically address macrolide use. Overall, current evidence generally supports the 2014 recommendations, particularly in children, but also leaves uncertainty regarding whether macrolides are universally necessary.
Background

A 2023 commentary critically evaluates the longstanding recommendation endorsing the combined use of intravenous cephalosporins and oral macrolide antibiotics, specifically azithromycin, for the treatment of acute chest syndrome (ACS) in patients with sickle cell disease (SCD). The commentary highlights that this recommendation, stemming from the 2014 NHLBI Expert Panel Report, is based on low-quality evidence and emphasizes the paucity of randomized controlled trials examining antibiotic efficacy and safety in ACS. Earlier investigations by the National Acute Chest Syndrome Study Group identified infections with Chlamydia pneumoniae and Mycoplasma pneumoniae as common causes of ACS in children, supporting macrolide use. However, more recent data indicate that these pathogens may be less prevalent than previously thought, and asymptomatic carriage is well-documented, raising concerns about empirical macrolide therapy’s justification. The widespread implementation of multiplex polymerase chain reaction (PCR) assays in clinical practice has enabled near-perfect negative predictive value for detecting these organisms, allowing clinicians to identify when macrolide treatment may be unnecessary. The commentary further discusses that despite this improved microbial diagnostic capacity, the entrenched practice of routinely administering macrolides to all ACS patients remains largely unchallenged, driven by historical precedent and potential immunomodulatory benefits observed in chronic pulmonary conditions. Nonetheless, robust evidence supporting immunomodulatory roles of macrolides in acute respiratory illnesses such as ACS is lacking, and corticosteroid use in ACS is regarded as controversial and generally not recommended. The author underscores the importance of antibiotic stewardship given the risk of macrolide resistance and cautions against continued use of macrolides in cases where multiplex PCR testing excludes C. pneumoniae and M. pneumoniae infections. Although macrolides have a favorable safety profile, their use without supportive data constitutes unnecessary exposure and contradicts principles of evidence-based medicine. Ultimately, the 2023 commentary calls for reevaluation of entrenched treatment paradigms based on low-quality evidence, advocating more selective and diagnostic-guided antibiotic use in ACS management. [1]

A 2024 clinical review provides a detailed overview and expert guidance on the management of acute pain in children and adolescents with SCD, emphasizing rapid assessment and early initiation of multimodal pain management. A comprehensive evaluation, including history, physical examination, and laboratory studies, is recommended to identify alternative diagnoses and SCD-related complications such as acute chest syndrome, stroke, and infection. Children with SCD are at increased risk for infections caused by encapsulated organisms, with Streptococcus pneumoniae, Salmonella, Escherichia coli, and Staphylococcus aureus among the most commonly isolated bacteria in the United States. Most institutions recommend ceftriaxone for empiric antibiotic therapy because of its long half-life and coverage of encapsulated organisms. However, repeated ceftriaxone exposure has rarely been associated with potentially fatal hemolysis; because of this risk, the authors’ institution uses ampicillin as first-line empiric antibiotic therapy. Notably, the review does not discuss the addition of a macrolide or otherwise provide recommendations regarding atypical antimicrobial coverage. [2]

The 2019 Cochrane systematic review was an update of the 2015 review evaluating the efficacy and safety of empiric antibiotic therapy for ACS in individuals with SCD. Because infectious and noninfectious causes of ACS may present similarly and numerous pathogens, including bacteria, have been implicated, antibiotics are commonly prescribed empirically for ACS; however, there is no standardized antibiotic approach, and treatment practices may vary geographically. The review sought randomized controlled trials (RCTs) evaluating antibiotics, either alone or in combination, compared with placebo, standard treatment, or alternative antibiotic regimens, with additional interest in differences according to treatment regimen, patient age, and geographic location. Consistent with the findings of the 2015 review, the updated literature search through July 2019 identified no eligible RCTs evaluating antibiotic treatment approaches for ACS in patients with SCD. Consequently, no quantitative synthesis or assessment of the comparative efficacy or safety of specific antibiotic regimens could be performed. The authors concluded that RCT evidence remains unavailable to establish an optimal antibiotic regimen for ACS, despite the routine empiric use of antibiotics in clinical practice, and noted that further trials were unlikely to be conducted; therefore, the Cochrane review would no longer be regularly updated. [3], [4]

Background References: [1] Hemenway CS. Re-examining a strong recommendation based on low-quality evidence in acute chest syndrome. Pediatr Blood Cancer. 2023;70(5):e30266. doi:10.1002/pbc.30266
[2] Payne JN, Gee BE. Management of Acute Sickle Cell Disease Pain. Pediatr Rev. 2024;45(1):26-38. doi:10.1542/pir.2022-005631
[3] Martí-Carvajal AJ, Conterno LO, Knight-Madden JM. Antibiotics for treating acute chest syndrome in people with sickle cell disease. Cochrane Database Syst Rev. 2015;2015(3):CD006110. Published 2015 Mar 6. doi:10.1002/14651858.CD006110.pub4
[4] Martí-Carvajal AJ, Conterno LO, Knight-Madden JM. Antibiotics for treating acute chest syndrome in people with sickle cell disease. Cochrane Database Syst Rev. 2019;9(9):CD006110. Published 2019 Sep 18. doi:10.1002/14651858.CD006110.pub5
Literature Review

A search of the published medical literature revealed 5 studies investigating the researchable question:

The most recent National Heart, Lung, and Blood Institute (NHLBI) guidelines strongly recommend that providers treat acute chest syndrome with an intravenous cephalosporin and an oral macrolide antibiotic, As these guidelines are from 2014, is there any updated evidence to continue to support or refute this recommendation. Particularly, with the increased use of viral respiratory panels and increasing resistance, is a macrolide antibiotic still needed.

Level of evidence

C - Multiple studies with limitations or conflicting results  Read more→



Please see Tables 1-5 for your response.


Association of Guideline-Adherent Antibiotic Treatment With Readmission of Children With Sickle Cell Disease Hospitalized With Acute Chest Syndrome
Design

Retrospective cohort study

N= 14,480 hospitalizations in 7,178 children

Objective To use a large, national database to describe patterns of antibiotic use for children with SCD hospitalized for ACS and to determine whether receipt of guideline-adherent antibiotics was associated with lower readmission rates
Study Groups

Guideline-adherent antibiotics (n= 10,654)

Non-guideline-adherent antibiotics (n= 3,826)

Inclusion Criteria Children (age 0-22 years) with a discharge diagnosis of SCD and either ACS or pneumonia from January 1, 2010, to December 31, 2016
Exclusion Criteria None specified
Methods Data were obtained from the Pediatric Health Information System, including discharge and billing data from 41 children's hospitals. Antibiotic regimens were categorized as guideline-adherent (macrolide with parenteral cephalosporin) or non-guideline-adherent. Outcomes were assessed for 7- and 30-day readmissions related to ACS and all-cause readmissions.
Duration January 1, 2010, to December 31, 2016
Outcome Measures

Primary: 7- and 30-day ACS-related and all-cause readmissions

Secondary: ICU admission, mechanical ventilation, length of stay, death

Baseline Characteristics   Macrolide With Cephalosporin (n= 10,654) Cephalosporin Without Macrolide (n= 1674) Macrolide Without Cephalosporin (n= 1202)  No Macrolide or Cephalosporin (n= 950) p-value

Age, years

          0-4

          5-9

          10-14

 

2875 (75.9%)

3230 (79.8%)

2225 (71.5%) 

 

626 (16.5%)

402 (9.9%)

306 (9.8%)      

 

198 (5.2%)

274 (6.8%) 

319 (10.3%)

 

88 (2.3%) 

141 (3.5%) 

260 (8.4%)

<0.001

-

-

Male 5890 (74.4%)  888 (11.2%)   623 (7.9%)  515 (6.5%) 0.23
ACS diagnosis code 8984 (79.0%)  635 (5.6%)   1037 (9.1%)  720 (6.3%) <0.001
Asthma diagnosis code 3573 (74.7%)  476 (10.0%)  400 (8.4%)  334 (7.0%) <0.001
Results   Macrolide With Cephalosporin (n= 10,654) Cephalosporin Without Macrolide (n= 1674) Macrolide Without Cephalosporin (n= 1202)  No Macrolide or Cephalosporin (n= 950) p-value
30-day ACS-related readmission 482 (4.5%)  93 (5.6%)  74 (6.2%)  83 (8.7%) <0.001
30-day all-cause readmission 1199 (11.3%)  267 (15.9%)  201 (16.7%)  274 (28.8%) <0.001
ICU admission 1285 (12.1%)  141 (8.4%)  89 (7.4%)  50 (5.3%) <0.001
Mechanical ventilation 496 (4.7%)  69 (4.1%)  24 (2.0%)  19 (2.0%) 0.024
Adverse Events Not specifically reported
Study Author Conclusions Current approaches to antibiotic treatment in children with ACS vary widely, but guideline-adherent therapy appears to result in fewer readmissions compared with non–guideline-adherent therapy. Efforts to increase the dissemination and implementation of SCD treatment guidelines are warranted.
Critique The study's large sample size and use of a national database provide robust data on antibiotic use patterns and outcomes. However, the retrospective design and reliance on administrative data may introduce coding errors and limit the ability to control for all confounding variables. The lack of randomized clinical trials in this area highlights the need for further research to strengthen the evidence base for guideline recommendations.
Table 1 References:
[5] Bundy DG, Richardson TE, Hall M, et al. Association of Guideline-Adherent Antibiotic Treatment With Readmission of Children With Sickle Cell Disease Hospitalized With Acute Chest Syndrome. JAMA Pediatr. 2017;171(11):1090-1099. doi:10.1001/jamapediatrics.2017.2526
Antibiotic Use and Respiratory Pathogens in Adults With Sickle Cell Disease and Acute Chest Syndrome
Design

Single-center, retrospective cohort analysis

N= 139 patients with 255 hospitalizations

Objective To characterize antibiotic use and pathogens identified from hospitalized adult patients with SCD treated for PNA or ACS and to assess the occurrence of readmissions associated with guideline-adherent compared with nonadherent treatment
Study Groups All patients (n= 139)
Inclusion Criteria Adult patients (age ≥ 18 years) with SCD hospitalized between August 1, 2014, and July 31, 2017, with a diagnosis of PNA or ACS at any time during hospital admission
Exclusion Criteria No exclusion criteria
Methods Retrospective cohort analysis of adult patients with SCD hospitalized with PNA or ACS. Data extracted included patient demographics, length of hospital stay, antibiotic use, microbiological results, and readmissions. Empirical antibiotic regimens were categorized based on MRSA activity, Pseudomonas aeruginosa activity, CAP pathogens, and atypical bacteria coverage. Regimens were deemed guideline adherent if they included a cephalosporin and a macrolide. Statistical analyses were performed using IBM SPSS v22.0
Duration August 1, 2014, to July 31, 2017
Outcome Measures

Primary: Characterization of antibiotic use and pathogens

Secondary: Occurrence of readmissions associated with guideline-adherent compared with nonadherent treatment

Baseline Characteristics   All patients (n= 139)
Age, years 28 (25-36)
Female 65%

Sickle cell disease type

          Hemoglobin SS

          Hemoglobin SC

          Hemoglobin S/O Arab

          Sickle beta+ Thalassemia

 

89.4%

9.4%

0.8%

0.4%

Empirical regimens

          Cephalosporin (3rd or 4th gen) + macrolide

          Respiratory flouroquinolone

          Pipercillin/tazobactam + macrolide

          Aminopenicillin/beta-lactamase inhibitor + macrolide

          Macrolide monotherapy

          No atypical coverage

 

43%

16%

16%

2%

1%

22%

Results Type of Readmission Guideline Adherent Non–Guideline Adherent p-value
ACS/Pneumonia-related 7-day 4 (3.7%) 0 (0) 0.04
All-cause 7-day 7 (6.4%) 7 (5.4%) 0.73
ACS/Pneumonia-related 30-day 7 (6.4%) 8 (6.2%) 0.93
All-cause 30-day 15 (13.8%) 30 (23.1%) 0.07
Adverse Events Adverse clinical outcomes included escalations in level of care from the hospital floor to the ICU, with 14 patients transferred to the ICU. One patient experienced in-hospital mortality attributed to septic shock secondary to an extended-spectrum β-lactamase-producing Escherichia coli urinary tract infection and PNA.
Study Author Conclusions These findings challenge existing knowledge regarding the most common pathogens in adults with SCD with ACS or PNA. Routine inclusion of a macrolide may not be necessary. Future studies focused on pathogen characterization with standardized assessment are necessary to determine appropriate empirical therapy in this population.
Critique The study provides valuable insights into antibiotic use and pathogen identification in adults with SCD and ACS or PNA. However, the retrospective design and single-center setting may limit the generalizability of the findings. The study did not aim to identify noninfectious causes of ACS, and associations between antibiotic selection and readmission rates may have been influenced by prescribing bias. Additionally, the small number of events limits the ability to adjust for clinical factors that may have affected readmission analysis.
Table 2 References:
[6] Claudio AM, Foltanski L, Delay T, et al. Antibiotic Use and Respiratory Pathogens in Adults With Sickle Cell Disease and Acute Chest Syndrome. Ann Pharmacother. 2019;53(10):991-996. doi:10.1177/1060028019846118
Association of Antibiotic Choice With Hospital Length of Stay and Risk Factors for Readmission in Patients With Sickle Cell Disease and Acute Chest Syndrome: An Observational Cohort Study
Design

Retrospective cohort study

N= 8,856

Objective To determine the association between use of specific cephalosporins and macrolides and hospital length of stay in patients with sickle cell disease (SCD) who are admitted with acute chest syndrome, and to determine treatment risk factors for acute chest syndrome–related 30-day readmission
Study Groups All patients (n= 8,856)
Inclusion Criteria Patients admitted to 48 US hospitals within the Pediatric Health Information System between January 2008 and December 2016 with associated ICD-9 or ICD-10 diagnoses of SCD and acute chest syndrome
Exclusion Criteria Not specified
Methods Data were analyzed with t tests, ANOVA, and bivariable and multivariable linear and logistic regressions. Patients were treated with intravenous cephalosporins (cefotaxime, ceftriaxone, cefuroxime) and macrolides (azithromycin, erythromycin). Other interventions included packed RBC transfusions, inhaled b-agonists, and inhaled steroids
Duration January 2008 to December 2016
Outcome Measures

Primary: Hospital length of stay, acute chest syndrome–related 30-day readmission

Secondary: All-cause 30-day readmission rate

Baseline Characteristics   All patients (n= 8,856)
Age at first hospitalization, years 8.7 (4.3–14.5)
Male 4,662 (52.7%)
HbSS 6,736 (76.1%)
Total no. of hospitalizations per patient during study period 1 (1–3)
Total hospital days per patient during study period 6 (3-13)
Index visits with a readmission for any reason within 30 days (all cause) 3,537 (16.7%)
Index visits with an ACS-related readmission within 30 days 2,108 (10.0%)
Number of ACS-related readmissions per patient within 30 days 0.24 ± 1.14
Deaths 37 (0.4%)
Results   All patients (n= 21,126) Ceftriaxone Ceftriaxone + Azithromycin
Length of stay, days 4.76 ± 4.62 4.75 ± 4.66 4.84 ± 4.74
30-day readmission 2,108 (10.0%) 715 (5.8%) 440 (4.3%)
Adverse Events Not specified
Study Author Conclusions Ceftriaxone alone or the combination of ceftriaxone and azithromycin was associated with the shortest length of stay and a reduced risk of acute chest syndrome–related readmission. All-cause 30-day readmission for acute chest syndrome is lower than that reported for all-cause readmissions for SCD and more consistent with rates of readmission for pneumonia in the general population.
Critique The study's strengths include a large sample size and the use of a well-established database, which enhances the reliability of the findings. However, limitations include potential confounding by indication due to the lack of clinical data such as laboratory values and physical examination findings. The retrospective design may also limit the ability to establish causality. Additionally, the study's focus on pediatric hospitals may limit generalizability to adult populations.
Table 3 References:
[7] Badaki-Makun O, Casella JF, Tackett S, Tao X, Chamberlain JM. Association of Antibiotic Choice With Hospital Length of Stay and Risk Factors for Readmission in Patients With Sickle Cell Disease and Acute Chest Syndrome: An Observational Cohort Study. Ann Emerg Med. 2020;76(3S):S37-S45. doi:10.1016/j.annemergmed.2020.08.011
Infectious Etiologies and Antimicrobial Management of Acute Chest Syndrome in Adult Sickle Cell Disease Patients: Pathogen Identification Patterns and Clinical Outcomes from a Five-Year Retrospective Study in Eastern Saudi Arabia
Design

Retrospective cohort study

N= 60

Objective To investigate the infectious etiologies, pathogen identification patterns, and antimicrobial management outcomes of ACS in adult SCD patients in Eastern Saudi Arabia
Study Groups All patients (n= 60)
Inclusion Criteria Patients aged ≥14 years with a diagnosis of SCD admitted with ACS to Dammam Medical Complex between 2018 and 2022
Exclusion Criteria Not specified
Methods Comprehensive microbiological evaluation including blood cultures, sputum cultures, and atypical pathogen testing. Empirical broad-spectrum antimicrobial therapy was administered, primarily ceftriaxone and azithromycin. Data on antimicrobial regimens, pathogen identification rates, and clinical outcomes were analyzed
Duration January 2018 to December 2022
Outcome Measures

Primary: Pathogen identification rates

Secondary: ICU admission rate, in-hospital mortality, antibiotic escalation rate

Baseline Characteristics   All patients (n= 60)
Age, years 24.6 ± 8.3
Male 35 (58.3%)
Homozygous (HbSS) 52 (86.7%)
On Hydroxyurea 20 (33.3%)
Pneumococcal vaccine, 30 (50.0%)
Annual influenza vaccine 18 (30.0%)
COVID-19 vaccine (≥1 dose) 24 (40.0%)
Results   ACS Episodes (n= 80)
Any identified pathogen 8 (10.0%)
Positive blood culture 5 (6.3%)
Positive sputum culture 4 (5.0%)
Mycoplasma pneumoniae identified 3 (3.8%)
ICU admission 15 (18.8%)
Mechanical ventilation 8 (10.0%)
Antibiotic therapy - ceftriaxone and azithromycin 76 (95.0%)
Length of hospital stay, days 7 (5–11)
In-hospital mortality 3 (3.8%)
Recurrent ACS 12 (20.0%)
30-day readmission 12 (15.0%)
Adverse Events Not specifically detailed in the provided text
Study Author Conclusions ACS in SCD patients demonstrated low rates of specific pathogen identification, supporting its multifactorial etiology. Broad-spectrum antimicrobial therapy was effective, but suboptimal vaccination rates highlight a critical gap in infection prevention strategies. Enhanced vaccination programs are urgently needed.
Critique The study provides valuable regional data on ACS in adult SCD patients, highlighting the importance of empirical antimicrobial therapy and vaccination. However, its retrospective design and single-center setting may limit generalizability. The low pathogen identification rate suggests a need for more sensitive diagnostic methods.
Table 4 References:
[8] Alsaeed A, Aleid R, Amin O, Alansari A, Aleid H, Aleid M. Infectious Etiologies and Antimicrobial Management of Acute Chest Syndrome in Adult Sickle Cell Disease Patients: Pathogen Identification Patterns and Clinical Outcomes from a Five-Year Retrospective Study in Eastern Saudi Arabia. Pathogens. 2025;14(11):1174. Published 2025 Nov 18. doi:10.3390/pathogens14111174

Revisiting acute chest syndrome (ACS) associated with sickle cell disease (SCD) vaso-occlusive pain episodes (VOE): Insight from a prospective, multicenter Phase-3 randomized controlled trial

Design

Cross-sectional analysis of data collected from a multicenter, double-blinded, randomized, placebo-controlled phase-3 trial

N= 271

Objective

To determine the prevalence of ACS in children and young adults hospitalized for SCD-VOE and describe emergency department (ED) presentation, clinical course and practice variation across institutions.

Study Groups

All patients (n= 271)

Inclusion Criteria

Not detailed in the study abstract

Exclusion Criteria

Not detailed in the study abstract

Methods

Cross-sectional analysis of data collected from a PECARN-endorsed multicenter, double-blinded, randomized, placebo-controlled phase-3 trial of intravenous arginine therapy in hospitalized patients with SCD-VOE aged 3-21 (NCT04839354) at 10 pediatric EDs across the US. ACS defined by radiology-interpreted chest radiograph (CXR) positive for new infiltrate and clinical team diagnosis. ACS severity was defined a priori as mild (no oxygen (O2) use or RBC transfusion), moderate (O2 use or transfusion), or severe (bilevel positive airway pressure [BiPAP] use, intubation, or pediatric intensive care unit [PICU] transfer).

Duration

Not detailed in the study abstract

Outcome Measures

Length of stay, tranfusions, PICU transfer

Baseline Characteristics

 

All patients (n= 271)

Age, years

15 (11-18)  

Male

51%   

HbSS/Sb°

74%  

Hydroxyurea

76%

Acute chest syndrome (ACS)

20%

Recieved antibiotics

          Ceftriaxone

          Ampicillin-sulbactam

          Vancomycin

          Other

          Azithromycin

96%

50%

28%

7%

11%

82%

Results

 

ACS (n= 54)

No ACS (n= 217)

p-value

Age, years

13 (9-16) 15 (12-18)  0.004 

Length of stay, hours

139 (93-189)  71 (46-113) <0.001 

Transfusions 

61% 14% <0.001

PICU transfer

15% 1% <0.001

Adverse Events

Not applicable

Study Author Conclusions

ACS remains common in patients with SCD-VOE (20%), with 14% of ACS diagnosed during their hospital stay. Two-thirds of subjects who developed ACS had a CXR done in the ED that was negative. ACS may have been missed in patients who did not get a CXR, and radiographic changes often lag behind symptoms. Lack of ACS-specific clinical signs and symptoms, including a normal ED respiratory exam in most patients, may delay diagnosis. Patients with inpatient-diagnosed ACS had a more severe hospital course vs those with ED-diagnosed ACS. Considerable practice variation exists in ACS management across institutions, with variable use of antibiotics and transfusion protocols. Further research on standardizing ACS treatment may be warranted. Oxygen desaturation in the ED was associated with a >3.6-fold greater risk of ACS, not included in prior ACS risk models.

 Critique

Study limitations include the cross-sectional design and the use of data collected from a clinical trial of intravenous arginine rather than a study specifically designed to evaluate ACS management. Additionally, variation in antibiotic, transfusion, and other treatment practices across institutions may complicate comparisons of clinical outcomes. Finally, the study is available only as an abstract, limiting assessment of the complete methodology, statistical analyses, potential confounders, and risk of bias.

Table 5 References:
[9] Hatabah D, Ahmad F, Airewele G, Akinsola B, Bakshi N, et al. Revisiting acute chest syndrome (ACS) associated with sickle cell disease (SCD) vaso-occlusive pain episodes (VOE): Insight from a prospective, multicenter Phase-3 randomized controlled trial. Blood . 2025; 146 (Supplement 1): 2946. doi:10.1182/blood-2025-2946