A Review of β-Lactam-Associated Neutropenia and Implications for Cross-reactivity

Antibiotic-associated neutropenia is marked by depletion of intestinal Lachnospiraceae in pediatric patients

Hematologic side effects are associated with prolonged antibiotic exposure in up to 34% of patients. Neutropenia, reported in 10-15% of patients, increases the risk of sepsis and death. Murine studies have established a link between the intestinal microbiota and normal hematopoiesis. We sought to identify predisposing factors, presence of microbiota-derived metabolites, and changes in intestinal microbiota composition in otherwise healthy pediatric patients who developed neutropenia after prolonged courses of antibiotics. In this multi-center study, patients with infections requiring anticipated antibiotic treatment of two or more weeks were enrolled. Stool samples were obtained at the start and completion of antibiotics and at the time of neutropenia. We identified 10 patients who developed neutropenia on antibiotics and 29 controls matched for age, sex, race, and ethnicity. Clinical data demonstrated no association between neutropenia and type of infection or type of antibiotic used; however intensive care unit admission and length of therapy were associated with neutropenia. Reduced intestinal microbiome richness and decreased abundance of Lachnospiraceae family members correlated with neutropenia. Untargeted stool metabolomic profiling revealed several metabolites that were depleted exclusively in patients with neutropenia, including members of the urea cycle pathway, pyrimidine metabolism and fatty acid metabolism that are known to be produced by Lachnospiraceae . Our study confirms a relationship between intestinal microbiota disruption and abnormal hematopoiesis and identifies taxa and metabolites likely to contribute to microbiota-sustained hematopoiesis. As the microbiome is a key determinant of stem cell transplant and immunotherapy outcomes, these findings are likely to be of broad significance.

Key Points

Neutropenia occurred in 17% of patients receiving prolonged antibiotic therapy.We found no association between neutropenia and type of infection or class of antibiotic used. Development of neutropenia after prolonged antibiotic treatment was associated with decreased prevalence of Lachnospiraceae and Lachnospiraceae metabolites such as citrulline.

Pharmacotherapeutic Considerations in the Treatment of Nontuberculous Mycobacterial Infections: A Primer for Clinicians

Nontuberculous mycobacteria (NTM) can cause a variety of infections, including serious pulmonary disease. Treatment encompasses polypharmacy, with a targeted regimen of 2-5 active medications, depending on site of infection, species, and clinical characteristics. Medications may include oral, intravenous, and inhalational routes. Medication acquisition can be challenging for numerous reasons, including investigational status, limited distribution models, and insurance prior authorization. Additionally, monitoring and managing adverse reactions and drug interactions is a unique skill set. While NTM is primarily medically managed, clinicians may not be familiar with the intricacies of medication selection, procurement, and monitoring. This review offers insights into the pharmacotherapeutic considerations of this highly complex disease state, including regimen design, medication acquisition, safety monitoring, relevant drug-drug interactions, and adverse drug reactions.

Ceftazidime/avibactam-induced severe neutropenia: A case report

Ceftazidime/avibactam is an important option for the treatment of infections caused by multidrug-resistant gram-negative bacteria. Haematological abnormalities are rare adverse events. We describe a case of a 63-year-old male who developed severe neutropenia following exposure to ceftazidime/avibactam in the intensive care unit for the treatment of abdominal infections. Six days after ceftazidime/avibactam was prescribed, the patient experienced a sheer drop in absolute neutrophil count, down to a minimum of 0.13 × 109 /L. A bone marrow examination showed neutrophilic maturation arrest. After careful screening of all drugs used by the patient and other potential causes of severe neutropenia, ceftazidime/avibactam was suspected to be the most likely culprit and was therefore replaced by cefoperazone/sulbactam, while a dose of colony-stimulating factor was given. The next day, neutrophils rose to 3.64 × 109 /L. To the best of our knowledge, this is the first case report of severe neutropenia associated with ceftazidime/avibactam. When neutropenia occurs during treatment, the clinician should keep this possibility in mind. Regular monitoring of neutrophil counts for timely recognition, immediate discontinuation of the drug and substitution of antibiotics are key steps in management.

Ceftriaxone-induced neutropenia successfully overcome by a switch to penicillin G in Cardiobacterium hominis endocarditis

Leukopenia, including agranulocytosis, is a severe complication of treatment with all β-lactam antibiotics. Its incidence increases with age. Cardiobacterium hominis endocarditis after implantation of an aortic valve bio-prosthesis in a 77-year-old woman was treated with ceftriaxone 2 g/day plus gentamicin 160 mg/day intravenously. On Day 25 of treatment, blood leukocytes had decreased to 1800/μl (neutrophils 370/μl). Antibiotic therapy was switched to penicillin G 20 million international units (IU)/day. Thereafter, blood leukocytes including neutrophils normalized suggesting that penicillin G was less bone marrow-toxic than ceftriaxone. High-dose ciprofloxacin, the alternative to penicillin G, was avoided because of the risk of cognitive and behavioral side effects. The present case suggests that with close laboratory monitoring a β-lactam with differing side chains should not be considered contraindicated after β-lactam antibiotic-induced neutropenia.

The Rare Adverse Effect of Cefepime-Induced Neutropenia

Cefepime is widely considered a safe and effective antibiotic, but it can have rare and serious side effects. We present a case of a 33-year-old female patient who developed severe and potentially life-threatening neutropenia after being on cefepime for 25 days. Despite extensive investigations, no other causes of neutropenia could be identified. Discontinuing the medication and administering a single dose of filgrastim produced a rapid and dramatic response. This case highlights the rare but serious risk of cefepime-induced neutropenia and underscores the need for clinicians to remain vigilant for this potential adverse effect. It is important to note that discontinuing the medication can rapidly reverse the effects, making timely recognition and intervention crucial for patient outcomes.

Evaluation of the safety of piperacillin-tazobactam extended infusion in pediatric cystic fibrosis patients

BACKGROUND

Patients with cystic fibrosis (CF) may be treated with piperacillin-tazobactam (PZT) for acute pulmonary exacerbations. Extending the infusion of PZT is one strategy to increase efficacy. Direct comparison, with respect to the incidence of acute kidney injury (AKI), between these two strategies has not been evaluated in pediatric patients with CF. The primary objective of this study was to compare the incidence of AKI in pediatric CF patients receiving extended infusion (EI) PZT versus traditional infusion (TI).

METHODS

This IRB-approved, retrospective analysis included patients ages 30 days to 18 years that received PZT for at least 48 h between January 1, 2008, and January 1, 2020. PZT was infused over 30 min (TI group) or 4 h (EI group).

RESULTS

Two hundred and four patients were included (TI: 109, EI: 95). Median age was 8 years (4-13) and 7 years (3-12) in the TI and EI groups (p = 0.15). The groups did not differ significantly in their baseline characteristics. There were 12 (11%) AKIs in the TI group and 8 (8.4%) in the EI group (p = 0.53). There was one occurrence of serum sickness in the TI group and none in the EI group. The incidence of thrombocytopenia was similar between the two groups. Median treatment duration was 8 days (5-11) and 9 days (5-13) for the TI and EI groups, respectively (p = 0.24).

CONCLUSIONS

There was no significant increase in AKI in pediatric patients with CF receiving PZT by EI compared with TI. EI may be utilized to optimize the pharmacokinetics of PZT in pediatric CF patients.

Antibiotic-Induced Neutropenia in Patients Receiving Outpatient Parenteral Antibiotic Therapy: a Retrospective Cohort Study

Our research objective was to describe the incidence and management of antibiotic-induced neutropenia in patients receiving outpatient parenteral antibiotic therapy (OPAT) at our institution over a 7-year period. We conducted a retrospective cohort study of patients followed by the OPAT clinic from 1 July 2016 to 30 March 2022 who developed antibiotic-induced neutropenia (defined as an absolute neutrophil count of ≤1.5 × 109/L). Patients receiving vancomycin in the OPAT clinic received weekly laboratory monitoring, while those receiving other antibiotics received laboratory monitoring at week 3 of therapy. Out of the 2,513 treatment courses, 55 cases of antibiotic-induced neutropenia were identified, resulting in an incidence of 2.2 cases per 100 treatment courses (95% confidence interval [CI], 1.7 to 2.9). Of the 45 cases for which a sole cause was identified, the three most common intravenous antibiotic culprits were vancomycin (21/541; 3.9%), ceftriaxone (10/490; 2.0%), and cloxacillin (2/103; 1.9%). Five (9.1%) patients had symptoms accompanying neutropenia that warranted hospital admission. There were no deaths, and all patients recovered their neutrophil count after antibiotic discontinuation or completion. In nine cases (16.3%), the culprit beta-lactam antibiotic was changed to another beta-lactam agent containing a structurally different side chain, with successful recovery of the neutrophil count in 9/9 (100%). The highest risk of antibiotic-induced neutropenia was associated with vancomycin, ceftriaxone, and cloxacillin in our cohort. With standardized outpatient monitoring during the third week of OPAT, cases of neutropenia can be detected early and managed without hospitalization. Data from our study also support the safety of switching to alternate beta-lactams with structurally different side chains.

Outpatient Parenteral Antibiotic Therapy in Older Adults

Outpatient parenteral antimicrobial therapy (OPAT) for older adults is a complex process that involves multiple stakeholders and care coordination, but it is a useful and patient-centered tool with opportunities for the treatment of complicated infections, improved patient satisfaction, and reduced health-care costs. Older age should not be an exclusion for OPAT but rather prompt the OPAT provider to thoroughly evaluate candidacy and safety. Amid the on-going COVID-19 pandemic, innovations in OPAT are needed to shepherd OPAT care into a more patient-centered, thoughtful practice, whereas minimizing harm to older patients from unnecessary health-care exposure and thus health-care associated infections.

Treatment of Bacterial Infections with β-Lactams: Cooperation with Innate Immunity

β-Lactams are the most widely prescribed antibiotics used for the control and treatment of bacterial infections. The direct effect of β-lactams on bacteria is well studied worldwide. In the context of infections and as a consequence of their direct activity against the pathogen, β-lactams also regulate antibacterial immune responses. This knowledge has led to the theorem that the effectiveness of β-lactam treatment results from the synergy between the drug and the immune response. Key players in this immune response, with an essential role in the clearance of live and dead bacteria, are the myeloid cells. In this review, we summarize the data that shed light on how β-lactams interact with myeloid cells during bacterial infection treatment.

Cefepime-Induced Neutropenia: A Case Report and Literature Review

Cefepime is a fourth-generation cephalosporin utilized in treatment of multiple Gram-negative and -positive infections. The current report presents a case of 50-year-old man admitted with epidural abscess who developed neutropenia after prolonged use of cefepime. The neutropenia developed after 24 days of cefepime treatment and resolved 4 days after cessation of cefepime. Assessment of the patient's profile indicated no other possible cause for neutropenia. A literature review was done, and is presented herein to compare and identify the pattern of cefepime-induced neutropenia in 15 patients. The data presented in this article highlight that despite its rarity, cefepime-induced neutropenia should be considered by clinicians when planning a prolonged course of cefepime.

Recent Updates in Antimicrobial Stewardship in Outpatient Parenteral Antimicrobial Therapy

Purpose of Review

Antimicrobial stewardship within acute care is common and has been expanding to outpatient areas. Some inpatient antimicrobial stewardship tactics apply to outpatient parenteral antimicrobial therapy (OPAT) and complex outpatient antimicrobial therapy (COpAT) management, but differences do exist.

Recent Findings

OPAT/COpAT is a growing area of practice and research with its own unique considerations for antimicrobial stewardship. Potential ideas for antimicrobial stewardship in the OPAT/COpAT setting include redesigning the regimen to COpAT instead of OPAT, ensuring the use of the shortest effective duration of antimicrobial therapy; using antimicrobials dosed less frequently, such as long-acting glycopeptides; optimizing antimicrobial susceptibility testing reporting for common OPAT/COpAT drugs; and establishing routine laboratory and safety monitoring. Future consensus is needed to determine validated OPAT program metrics and outcomes.

Summary

As more focus is placed on outpatient antimicrobial stewardship, clinicians practicing in OPAT should publish more data regarding OPAT program methods and outcomes as they relate to antimicrobial stewardship. These can involve patient clinical outcomes, OPAT readmission rates, OPAT therapy completion, and central line-related complications.