Comparison of Neutropenia Associated with Ceftaroline or Ceftriaxone in Patients Receiving at Least 7 Days of Therapy for Severe Infections

The bacterial microbiota regulates normal hematopoiesis via metabolite-induced type 1 interferon signaling

Antibiotic therapy, especially when administered long term, is associated with adverse hematologic effects such as cytopenia. Signals from the intestinal microbiota are critical to maintain normal hematopoiesis, and antibiotics can cause bone marrow suppression through depletion of the microbiota. We reported previously that STAT1 signaling is necessary for microbiota-dependent hematopoiesis, but the precise mechanisms by which the gut microbiota signals to the host bone marrow to regulate hematopoiesis remain undefined. We sought to identify the cell type(s) through which STAT1 promotes microbiota-mediated hematopoiesis and to elucidate which upstream signaling pathways trigger STAT1 signaling. Using conditional knockout and chimeric mice, we found that the microbiota induced STAT1 signaling in non-myeloid hematopoietic cells to support hematopoiesis and that STAT1 signaling was specifically dependent on type I interferons (IFNs). Indeed, basal type I IFN signaling was reduced in hematopoietic progenitor cells with antibiotic treatment. In addition, we discovered that oral administration of a commensal-derived product, NOD1 ligand, rescues the hematopoietic defects induced by antibiotics in mice. Using metabolomics, we identified additional microbially produced candidates that can stimulate type I IFN signaling to potentially rescue the hematopoietic defects induced by antibiotics, including phosphatidylcholine and γ-glutamylalanine. Overall, our studies define a signaling pathway through which microbiota promotes normal hematopoiesis and identify microbial metabolites that may serve as therapeutic agents to ameliorate antibiotic-induced bone marrow suppression and cytopenia.

[Risk factors for neutropenia of late newborns]

OBJECTIVE

To study the risk factors and treatment for neutropenia of late newborns (NLN).

METHODS

Related clinical data were collected from the preterm infants and critically ill neonates who were admitted to the neonatal intensive care unit from July 2019 to January 2020. A total of 46 newborns with a blood absolute neutrophil count (ANC) of < 1.5×10⁹/L for two consecutive times at weeks 2-4 after birth were enrolled as the NLN group. A total of 92 late newborns with a blood ANC of ≥ 1.5×10⁹/L, matched at a ratio of 1:2, were enrolled as the control group. Possible risk factors associated with NLN and the treatment process were recorded. A logistic regression analysis was performed to identify the risk factors for NLN.

RESULTS

Among the 46 neonates in the NLN group, 29 had a gestational age of < 32 weeks, 14 had a gestational age of 32-37 weeks, and 3 had a gestational age of > 37 weeks. There was no significant difference between the two groups in the incidence rates of gestational hypertension, premature rupture of membranes > 18 hours and intrauterine distress, 5-minute Apgar score, the duration of positive pressure ventilation, the incidence rate of early-onset sepsis, and the type of initially used antibiotics (P > 0.05). Compared with the control group, the NLN group had a higher incidence rate of late-onset sepsis and a longer duration of antibiotic use (P < 0.05). Late-onset sepsis and prolonged duration of antibiotic use were independent risk factors for NLN (P < 0.05). With the presence of late-onset sepsis, the risk of NLN was increased by 1.537 times in neonates, and the risk of NLN was increased by 76.9% for every 3-day increase in the duration of antibiotic use. The mean age at the diagnosis of NLN was (21±6) days for the 46 neonates in the NLN group. Thirteen neonates with NLN were administered with recombinant human granulocyte colony-stimulating factor (G-CSF, 10 μg/kg) once or twice. O the 13 neonates, 6 had an ANC of < 0.5×10⁹/L and 7 had a gestational age of < 32 weeks or severe disease conditions. After treatment the ANC returned to > 1.0×10⁹/L in the 13 neonates. No drug-related adverse reactions were found. After the diagnosis of NLN, 2 neonates developed sepsis, and the remaining 44 neonates did not develop any common purulent infections.

CONCLUSIONS

The risk of NLN increases with the presence of late-onset sepsis and the increase in the duration of antibiotic use. NLN is generally a benign process. G-CSF appears to be safe and effective for NLN with severe disease conditions or severe reduction in ANC.

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

OBJECTIVE

To review the incidence, management, and current understanding of the pathophysiology of β-lactam-induced neutropenia and to critically evaluate the practicality and safety of direct substitution to an alternative β-lactam in the setting of this reaction.

DATA SOURCES

A literature analysis using the PubMed and Ovid search engines (July 1968 to October 2020) was performed using the search terms neutropenia, leukopenia, β-lactam, nonchemotherapy, agranulocytosis, and G-CSF (granulocyte colony-stimulating factor).

STUDY SELECTION AND DATA EXTRACTION

The included English-language studies evaluated the incidence, mechanism, and/or management of β-lactam-induced neutropenia in pediatric or adult patients.

DATA SYNTHESIS

Drug-induced neutropenia is a well-documented adverse reaction of β-lactam antibiotics, with an incidence of approximately 10% following at least 2 weeks of intravenous therapy. However, multiple gaps in knowledge remain in the mechanism of pathophysiology and optimal management of this reaction. Both direct toxic and immune-mediated mechanisms have been implicated. Although the cornerstone of management includes cessation of the offending agent, controversy exists on the appropriateness of direct substitution or future use of an alternative β-lactam.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Given the frequency of use and superiority of β-lactams over alternative therapy for several infectious disease states, practical recommendations are needed on the management and safe use of β-lactams following β-lactam-induced neutropenia.

CONCLUSION

Future use of β-lactams with differing R1 side chains, particularly those from a separate class, should not be deemed contraindicated following β-lactam-induced neutropenia and may be considered when indicated, with close laboratory monitoring.

Emerging drugs for treating methicillin-resistant Staphylococcus aureus

Introduction: In clinical practice, methicillin-resistant Staphylococcus aureus (MRSA) represents a major threat and has been associated with high rates of inadequate antibiotic treatment and significant increases in morbidity, mortality, and overall healthcare costs. The association between the prescription of an inappropriate or delayed antibiotic and impaired clinical outcomes has been widely described. Areas covered: To address the threat of MRSA, many new therapeutic options with a peculiar activity against MRSA have been recently developed and approved. New agents are characterized by specific issues in terms of spectrum of activity, pharmacokinetics, risk of drug-drug interactions, and toxicity, with potential advantages that should be considered in everyday clinical practice. Expert opinion: The most attractive characteristic of new drugs is represented by the broad spectrum of activity against multidrug-resistant pathogens; moreover, new compounds in most cases are characterized by favorable toxicity profiles compared with old drugs currently used in clinical practice. Some of the new antimicrobials will be also available as oral formulations, with the potential for oral switch, even in infections due to resistant pathogens. In particular conditions/populations (e.g. liver failure, renal disease, pregnancy, diabetic, children, and elderly), novel antibiotics with reduced toxicity could be an important option, including after hospital discharge.