Epidemiology of Vancomycin-Induced Neutropenia In Patients Receiving Home Intravenous Infusion Therapy

Hematological adverse events associated with anti-MRSA agents: a real-world analysis based on FAERS

This study investigated the patterns of hematological adverse events related to daptomycin (DAP), tigecycline (TIG), vancomycin (VAN) and linezolid (LIN) in the FDA Adverse Event Reporting System (FAERS). Adverse event associations were analyzed through calculating reporting odds ratio (ROR), proportional reporting ratio (PRR), multiple gamma Poisson shrinkage (MGPS), and Bayesian confidence propagation neural network (BCPNN). A comprehensive descriptive analysis was also conducted considering factors such as age, gender, daily dose, cumulative dose, and time to onset. The leading hematologic adverse events were eosinophilia for daptomycin, coagulation abnormalities and thrombocytopenia for tigecycline, thrombocytopenia, neutropenia, and anemia for linezolid, and thrombocytopenia, eosinophilia, and neutropenia for vancomycin. Most of the affected patients were over 55 years old. Daily doses for the tigecycline and daptomycin groups exceeded the standard daily dose. The times to onset were 14.00 days for daptomycin (interquartile range [IQR], 4.00-21.00), 6.00 days for tigecycline (IQR, 2.00-9.00), 10.00 days for linezolid (IQR, 4.00-16.5), and 10.00 days for vancomycin (IQR,5.00-20.00). It is essential to intensify early monitoring and identification of these adverse events, especially in the context of off-label dosages and for elderly patients and individuals taking medication for over one week.

[Intraosseous vancomycin in total knee arthroplasty]

INTRODUCTION

intravenous antibiotic prophylaxis has significantly reduced the incidence of periprosthetic joint infection (PJI) in knee surgeries. However, for patients colonized with methicillin-resistant Staphylococcus aureus (MRSA) or those at risk of colonization, prophylaxis should include vancomycin. Intraosseous (IO) administration of vancomycin could enhance its effectiveness in total knee arthroplasty (TKA).

MATERIAL AND METHODS

a retrospective review was conducted, including 143 patients at risk of PJI scheduled for TKA who received IO vancomycin along with intravenous (IV) cefazolin, referred to as group I (GI), between May 2021 and December 2022. The occurrence of complications in the first three postoperative months was evaluated. Results were compared with 140 patients without risk factors who received standard IV prophylaxis, designated as group II (GII).

RESULTS

in GI, 500 mg of IO vancomycin was administered, injected into the proximal tibia, in addition to standard IV prophylaxis. In GII, patients received only IV cefazolin. The incidence of complications was 1.64% in GI and 1.4% in GII. The PJI rate at 90 postoperative days was 0.69% in GI and 0.71% in GII.

CONCLUSIONS

IO vancomycin administration, along with standard IV prophylaxis, provides a safe and effective alternative for patients at risk of MRSA colonization. This approach minimizes complications associated with IV vancomycin use and addresses logistical challenges of timely administration.

Vancomycin-Induced Neutropenia With Subsequent Perioperative Readministration: A Case Report

Vancomycin (VCM), an essential antibiotic for antimicrobial-resistant Gram-positive cocci, can lead to complications such as neutropenia. Here, we present a case of a 25-year-old male with noncommunicating hydrocephalus due to an intraventricular tumor who developed neutropenia during VCM therapy. Despite the suspected VCM-induced neutropenia, short-term readministration was deemed necessary for perioperative infection prophylaxis. This patient was readministered without neutropenia. A review of the literature revealed an earlier onset of VCM-induced neutropenia than that previously reported, emphasizing the importance of vigilant monitoring. Although readministration of VCM in patients with neutropenia is uncommon, it may be feasible with careful risk assessment, particularly in cases of mild neutropenia and short-term therapy. However, the mechanisms underlying VCM-induced neutropenia remain unclear, necessitating further research on the optimal management strategies.

Two Cases of Vancomycin-Induced Neutropenia

(1) Background: The incidence of vancomycin-induced neutropenia in hospitalized patients is estimated to be around 2 to 8 percent Data surrounding vancomycin-induced neutropenia is limited as it is based on a small number of observational case reports. Additionally, it is difficult to provide generalized conclusions since patient characteristics and indications for treatment vary between reports. (2) Case Reports: We present two cases of vancomycin-induced neutropenia that occurred at our facility; a 50-year-old male who developed neutropenia after treatment with vancomycin for a gluteal abscess and a 51-year-old female who developed neutropenia after treatment with vancomycin for lumbar osteomyelitis. In both cases, neutropenia resolved within 2 days of discontinuation of vancomycin. (3) Conclusions: Vancomycin-induced neutropenia is thought to be a relatively uncommon adverse drug reaction. These two cases of neutropenia likely caused by prolonged exposure to vancomycin occurred at our facility within 3 months of each other. Additional studies are needed to better understand the true incidence of this adverse drug reaction and to identify risk factors that may predispose patients to vancomycin-induced neutropenia.

Microbiota Influences on Hematopoiesis and Blood Cancers: New Horizons?

Hematopoiesis governs the generation of immune cells through the differentiation of hematopoietic stem cells (HSC) into various progenitor cells, a process controlled by intrinsic and extrinsic factors. Among extrinsic factors influencing hematopoiesis is the microbiota, or the collection of microorganisms present in various body sites. The microbiota has a profound impact on host homeostasis by virtue of its ability to release various molecules and structural components, which promote normal organ function. In this review, we will discuss the role of microbiota in influencing hematopoiesis and how disrupting the microbiota/host network could lead to hematologic malignancies, as well as highlight important knowledge gaps to move this field of research forward.

SIGNIFICANCE

Microbiota dysfunction is associated with many pathologic conditions, including hematologic malignancies. In this review, we discuss the role of microbiota in influencing hematopoiesis and how disrupting the microbiota/host network could lead to hematologic malignancies. Understanding how the microbiota influences hematologic malignancies could have an important therapeutic impact for patients.

Detection of drug safety signal of drug-induced neutropenia and agranulocytosis in all-aged patients using electronic medical records

PURPOSE

We explored the adverse drug reaction signals of drug-induced neutropenia (DIN) and drug-induced agranulocytosis (DIA) in hospitalized patients and evaluated the novelty of these correlations.

METHOD

A two-step method was established to identify the relationship between drugs and DIN or DIA using 5-year electronic medical records (EMRs) obtained from 242 000 patients at Qilu Hospital of Shandong University. First, the drugs suspected to induce DIN or DIA were selected. The associations between suspected drugs and DIN or DIA were evaluated by a retrospective cohort study using unconditional logistic regression analysis and multiple linear regression model.

RESULTS

Twelve suspected drugs (vancomycin, meropenem, voriconazole, acyclovir, ganciclovir, fluconazole, oseltamivir, linezolid, compound borax solution, palonosetron, polyene phosphatidylcholine, and sulfamethoxazole) were associated with DIN, and six suspected drugs (vancomycin, voriconazole, acyclovir, ganciclovir, fluconazole, and oseltamivir) were associated with DIA. The multivariate linear regression model revealed that nine drugs (vancomycin, meropenem, voriconazole, ganciclovir, fluconazole, oseltamivir, compound borax solution, palonosetron, and polyene phosphatidylcholine) and four drugs (vancomycin, voriconazole, ganciclovir, and fluconazole) were found to be associated with DIN and DIA, respectively. While logistic regression analysis revealed that palonosetron and ganciclovir were associated with DIN and DIA, respectively.

CONCLUSION

Palonosetron and ganciclovir were found to be correlated with drug-induced granulocytopenia. The results of this study provide an early warning of drug safety signals for drug-induced granulocytopenia, facilitating a quick and appropriate response for clinicians.

Functional liquid-infused PDMS sponge-based catheter with antithrombosis, antibacteria, and anti-inflammatory properties

A functional liquid-infused catheter surface strategy has recently attracted increasing attention for blood transport with the remarkable antibiofouling performance. Nevertheless, constructing porous structure inside a catheter with effective functional liquid-locking ability remains extremely challenging. Herein, the central cylinder mold and sodium chloride particle templates technique was used to create a PDMS sponge-based catheter that stores a stable functional liquid. Our multifunctional liquid-infused PDMS sponge-based catheter can not only exhibit bacterial resistant, less macrophages infiltration, a slighter inflammation response, but also capability to prevent platelet adhesion and activation, and impressively reduce thrombosis in vivo even at high shear. Therefore, these desirable properties will endow the prospective practical applications and serve as a watershed moment in the development of biomedical devices.

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.

Vancomycin-Induced Maturation Arrest with Reactive Promyelocyte Proliferation: A Diagnostic and Therapeutic Challenge

Drug-induced leukopenia is a diagnostic and therapeutic challenge. A detailed clinical history is a must to come to a right diagnosis. Certain drugs are known to cause bone marrow suppression, leukopenia, myeloid maturation arrest, and reactive promyelocyte proliferation. Here, we report an unusual case of vancomycin-induced maturation arrest with marked promyelocyte proliferation in a 47-year-old male patient who was being treated for novel coronavirus disease 2019 (COVID-19) infection. Most times, this reactive promyelocyte proliferation is confused with neoplastic promyelocytes, leading to incorrect diagnosis and management.

Bioinspired ultra-low fouling coatings on medical devices to prevent device-associated infections and thrombosis

Addressing thrombosis and biofouling of indwelling medical devices within healthcare institutions is an ongoing problem. In this work, two types of ultra-low fouling surfaces (i.e., superhydrophobic and lubricant-infused slippery surfaces) were fabricated to enhance the biocompatibility of commercial medical grade silicone rubber (SR) tubes that are widely used in clinical care. The superhydrophobic (SH) coatings on the tubing substrates were successfully created by dip-coating in superhydrophobic paints consisting of polydimethylsiloxane (PDMS), perfluorosilane-coated hydrophobic zinc oxide (ZnO) and copper (Cu) nanoparticles (NPs) in tetrahydrofuran (THF). The SH surfaces were converted to lubricant-infused slippery (LIS) surfaces through the infusion of silicone oil. The anti-biofouling properties of the coatings were investigated by adsorption of platelets, whole blood coagulation, and biofilm formation in vitro. The results revealed that the LIS tubes possess superior resistance to clot formation and platelet adhesion than uncoated and SH tubes. In addition, bacterial adhesion was investigated over 7 days in a drip-flow bioreactor, where the SH-ZnO-Cu tube and its slippery counterpart significantly reduced bacterial adhesion and biofilm formation of Escherichia coli relative to control tubes (>5 log10 and >3 log10 reduction, respectively). The coatings also demonstrated good compatibility with fibroblast cells. Therefore, the proposed coatings may find potential applications in high-efficiency on-demand prevention of biofilm and thrombosis formation on medical devices to improve their biocompatibility and reduce the risk of complications from medical devices.

Intraosseous Regional Administration of Vancomycin in Primary Total Knee Arthroplasty Does Not Increase the Risk of Vancomycin-Associated Complications

BACKGROUND

Periprosthetic joint infection (PJI) after total knee arthroplasty (TKA) is a rare but major complication. Owing to an increasing antibiotic resistance in bacteria causing PJI, vancomycin has been investigated as a prophylactic agent. Intraosseous regional administration (IORA) of vancomycin achieves significantly higher local tissue concentrations than systemic administration. There are limited data on IORA of vancomycin with respect to vancomycin-associated complications.

METHODS

Single-surgeon retrospective review of primary TKA was performed between January 2015 and May 2019. All patients received 500 mg of IORA of vancomycin after tourniquet inflation and 3 × 1 g intravenous cefazolin in 24 hrs. Preoperative data collected included age, gender, body mass index, American Society of Anesthesiologists (ASA) score, diabetes, and chronic kidney disease (CKD). We documented in-hospital complications and complications requiring readmission within 12 months. Primary outcome measures were the incidence of acute kidney injury (AKI), 'red man syndrome' (RMS), and neutropenia. The secondary outcome measure was PJI incidence.

RESULTS

We identified 631 primary TKAs in 556 patients, of which 331 received IORA. The mean age was 67.7 ± 8.7 years, and 57.8% were women. CKD was prevalent in 17.2% of the cohort. AKI occurred in 25 (3.9%) cases. After controlling for covariates, CKD was the only significant predictor of AKI (odds ratio = 3.035, P = .023). RMS and neutropenia were not observed in this cohort. The 90-day PJI rate was 0%, and the 1-year PJI rate was 0.2%.

CONCLUSIONS

Low-dose IORA of vancomycin in addition to standard intravenous systemic cefazolin prophylaxis in TKA is safe without significant adverse effects of vancomycin such as AKI, RMS, or neutropenia.

Evolving Role of Pharmacogenetic Biomarkers to Predict Drug-Induced Hematological Disorders

ABSTRACT

Drug-induced hematological disorders constitute up to 30% of all blood dyscrasias seen in the clinic. Hematologic toxicity from drugs may range from life-threatening marrow aplasia, agranulocytosis, hemolysis, thrombosis to mild leukopenia, and thrombocytopenia. Pathophysiologic mechanisms underlying these disorders vary from an extension of the pharmacological effect of the drug to idiosyncratic and immune-mediated reactions. Predicting these reactions is often difficult, and this makes clinical decision-making challenging. Evidence supporting the role of pharmacogenomics in the management of these disorders in clinical practice is rapidly evolving. Despite the Clinical Pharmacology Implementation Consortium and Pharmacogenomics Knowledge Base recommendations, few tests have been incorporated into routine practice. This review aims to provide a comprehensive summary of the various drugs which are implicated for the hematological adverse events, their underlying mechanisms, and the current evidence and practical recommendations to incorporate pharmacogenomic testing in clinical care for predicting these disorders.

A conformally adapted all-in-one hydrogel coating: towards robust hemocompatibility and bactericidal activity

A conformally adapted all-in-one hydrogel coatings that exhibit both hemocompatibility and bactericidal activity possess the potential for applications in blood-contacting devices.

Clinical and Pharmacokinetic Outcomes of Peak-Trough-Based Versus Trough-Based Vancomycin Therapeutic Drug Monitoring Approaches: A Pragmatic Randomized Controlled Trial

BACKGROUND

Vancomycin therapeutic drug monitoring (TDM) is based on achieving 24-h area under the concentration-time curve to minimum inhibitory concentration cure breakpoints (AUC24/MIC). Approaches to vancomycin TDM vary, with no head-to-head randomized controlled trial (RCT) comparisons to date.

OBJECTIVES

We aimed to compare clinical and pharmacokinetic outcomes between peak-trough-based and trough-only-based vancomycin TDM approaches and to determine the relationship between vancomycin AUC24/MIC and cure rates.

METHODS

A multicentered pragmatic parallel-group RCT was conducted in Hamad Medical Corporation hospitals in Qatar. Adult non-dialysis patients initiated on vancomycin were randomized to peak-trough-based or trough-only-based vancomycin TDM. Primary endpoints included vancomycin AUC24/MIC ratio breakpoint for cure and clinical effectiveness (therapeutic cure vs therapeutic failure). Descriptive, inferential, and classification and regression tree (CART) statistical analyses were applied. NONMEM.v.7.3 was used to conduct population pharmacokinetic analyses and AUC24 calculations.

RESULTS

Sixty-five patients were enrolled [trough-only-based-TDM (n = 35) and peak-trough-based-TDM (n = 30)]. Peak-trough-based TDM was significantly associated with higher therapeutic cure rates compared to trough-only-based TDM [76.7% vs 48.6%; p value = 0.02]. No statistically significant differences were observed for all-cause mortality, neutropenia, or nephrotoxicity between the two groups. Compared to trough-only-based TDM, peak-trough-based TDM was associated with less vancomycin total daily doses by 12.05 mg/kg/day (p value = 0.027). CART identified creatinine clearance (CLCR), AUC24/MIC, and TDM approach as significant determinants of therapeutic outcomes. All patients [n = 19,100%] with CLCR ≤ 7.85 L/h, AUC24/MIC ≤ 1256, who received peak-trough-based TDM achieved therapeutic cure. AUC24/MIC > 565 was identified to be correlated with cure in trough-only-based TDM recipients [n = 11,84.6%]. No minimum AUC24/MIC breakpoint was detected by CART in the peak-trough-based group.

CONCLUSION

Maintenance of target vancomycin exposures and implementation of peak-trough-based vancomycin TDM may improve vancomycin-associated cure rates. Larger scale RCTs are warranted to confirm these findings.

Agranulocytosis Induced by Vancomycin. Case Report and Literature Review

Patient: Male, 38

Final Diagnosis: Agranulocytosis induced by Vancomycin

Symptoms: Fever • pain

Medication: Vancomycin

Clinical Procedure: Antibiotic treatment

Specialty: Hematology

Hematopoiesis and the bacterial microbiome

Recent studies have revealed that the intestinal bacterial microbiome plays an important role in the regulation of hematopoiesis. A correlation between adverse hematologic effects and imbalance of the intestinal microbiome, or dysbiosis, is evident in several human conditions, such as inflammatory bowel disease, obesity, and, critically, in the setting of antibiotic exposure. Here we review the effects of gut dysbiosis on the hematological compartment and our current understanding of the mechanisms through which changes in the bacterial microbiome affect hematopoiesis.

Comparative analysis of neutropenia in patients receiving prolonged treatment with ceftaroline

Objectives

Ceftaroline is often used in durations greater than that studied in clinical trials. Several retrospective, non-comparative studies have suggested a higher than anticipated incidence of neutropenia in patients receiving prolonged treatment with ceftaroline. We sought to determine if ceftaroline was associated with neutropenia by comparing the incidence with ceftaroline treatment with treatment with several comparative antibiotics.

Methods

Patients receiving 14 or more consecutive days of treatment with ceftaroline were compared with patients receiving cefazolin, daptomycin, linezolid, nafcillin or vancomycin (control group). The primary outcome was the development of neutropenia. Multivariate logistic regression and propensity score weighting using inverse probability weights with regression adjustment were used to control for confounding variables.

Results

A total of 753 patients were included (53 that received ceftaroline and 700 that received a comparative antibiotic). Ceftaroline was associated with a greater incidence of neutropenia as compared with the control group (17.0% versus 3.9%, P < 0.001). Several covariates were also associated with neutropenia and included younger age, lower baseline absolute neutrophil count, liver disease and bone and joint infections. After controlling for these confounders, receipt of ceftaroline continued to be associated with the development of neutropenia (adjusted OR 3.97, P = 0.003). Analysis after propensity score weighting confirmed this finding.

Conclusions

The results of this study suggest that prolonged treatment with ceftaroline is associated with a greater incidence of neutropenia as compared with other antibiotics that are often used for treatment of staphylococcal infections. Careful monitoring of absolute neutrophil count is recommended in patients receiving >14 days of ceftaroline.

Antibiotic-loaded nanoparticles targeted to the site of infection enhance antibacterial efficacy

Bacterial resistance to antibiotics has made it necessary to resort to antibiotics that have considerable toxicities. Here, we show that the cyclic 9-amino acid peptide CARGGLKSC (CARG), identified via phage display on Staphylococcus aureus (S. aureus) bacteria and through in vivo screening in mice with S. aureus-induced lung infections, increases the antibacterial activity of CARG-conjugated vancomycin-loaded nanoparticles in S. aureus-infected tissues and reduces the needed overall systemic dose, minimizing side effects. CARG binds specifically to S. aureus bacteria but not Pseudomonas bacteria in vitro, selectively accumulates in S. aureus-infected lungs and skin of mice but not in non-infected tissue and Pseudomonas-infected tissue, and significantly enhances the accumulation of intravenously injected vancomycin-loaded porous silicon nanoparticles bearing the peptide in S. aureus-infected mouse lung tissue. The targeted nanoparticles more effectively suppress staphylococcal infections in vivo relative to equivalent doses of untargeted vancomycin nanoparticles or of free vancomycin. The therapeutic delivery of antibiotic-carrying nanoparticles bearing peptides targeting infected tissue may help combat difficult-to-treat infections.

Non-chemotherapy drug-induced neutropenia: key points to manage the challenges

Non-chemotherapy idiosyncratic drug-induced neutropenia (IDIN) is a relatively rare but potentially fatal disorder that occurs in susceptible individuals, with an incidence of 2.4 to 15.4 cases per million population. Affected patients typically experience severe neutropenia within several weeks to several months after first exposure to a drug, and mortality is ∼5%. The drugs most frequently associated with IDIN include metamizole, clozapine, sulfasalazine, thiamazole, carbimazole, amoxicillin, cotrimoxazole, ticlopidine, and valganciclovir. The idiosyncratic nature of IDIN, the lack of mouse models and diagnostic testing, and its low overall incidence make rigorous studies to elucidate possible mechanisms exceptionally difficult. An immune mechanism for IDIN involving neutrophil destruction by hapten (drug)-specific antibodies and drug-induced autoantibodies is frequently suggested, but strong supporting evidence is lacking. Although laboratory testing for neutrophil drug-dependent antibodies is rarely performed because of the complexity and low sensitivity of tests currently in use, these assays could possibly be enhanced by using reactive drug metabolites in place of the parent drug. Patients typically experience acute, severe neutropenia, or agranulocytosis (<0.5 × 10⁹ neutrophils/L) and symptoms of fever, chills, sore throat, and muscle and joint pain. Diagnosis can be difficult, but timely recognition is critical because if left untreated, there is an increase in mortality. Expanded studies of the production and mechanistic role of reactive drug metabolites, genetic associations, and improved animal models of IDIN are essential to further our understanding of this important disorder.

Review on Usage of Vancomycin in Livestock and Humans: Maintaining Its Efficacy, Prevention of Resistance and Alternative Therapy

Vancomycin is one of the “last-line” classes of antibiotics used in the treatment of life-threatening infections caused by Gram-positive bacteria. Even though vancomycin was discovered in the 1950s, it was widely used after the 1980s for the treatment of infections caused by methicillin-resistant Staphylococci, as the prevalence of these strains were increased. However, it is currently evident that vancomycin-resistant Staphylococcus aureus and vancomycin-resistant Enterococci have developed for various reasons, including the use of avaparcin—an analog of vancomycin—as a feed additive in livestock. Therefore, prophylactic and empiric use of antibiotics and their analogues need to be minimized. Herein we discuss the rational use of vancomycin in treating humans, horses, farm animals, and pet animals such as dogs, cats, and rabbits. In present day context, more attention should be paid to the prevention of the emergence of resistance to antibiotics in order to maintain their efficacy. In order to prevent emergence of resistance, proper guidance for the responsible use of antimicrobials is indispensable. Therefore, almost all stakeholders who use antibiotics should have an in-depth understanding of the antibiotic that they use. As such, it is imperative to be aware of the important aspects of vancomycin. In the present review, efforts have been made to discuss the pharmacokinetics and pharmacodynamics, indications, emergence of resistance, control of resistance, adverse effects, and alternative therapy for vancomycin.

Glycopeptide-Induced Neutropenia: Cross-Reactivity Between Vancomycin and Teicoplanin

Objective:

To report teicoplanin-related neutropenia that developed after an episode of neutropenia induced by vancomycin therapy.

Case Summary:

A 57-year-old female suffered from osteomyelitis of the left humerus, with a white blood cell (WBC) count of 2.8 × 103/mm3 and absolute neutrophil count (ANC) of 0.28 × 103/mm3, occurring after 24 days of vancomycin therapy. Vancomycin was changed to teicoplanin and the agranulocytosis resolved 4 days later. However, a new episode of neutropenia, with a WBC count of 2.8 × 103/mm3 and ANC of 0.448 × 103/mm3, occurred 11 days after teicoplanin initiation. Agranulocytosis resolved 4 days following withdrawal of teicoplanin.

Discussion:

Because of the close time relationship between drug administration and the development of symptoms and signs, as well as between drug withdrawal and changes in WBC count and ANC, the episodes of neutropenia were suspected to be drug related. Teicoplanin-induced agranulocytosis that followed vancomycin-induced agranulocytosis suggests a possible cross-reactivity between the 2 drugs. Both reactions were categorized as probable according to the Naranjo probability scale.

Conclusions:

For all patients with vancomycin-induced neutropenia, possible cross-reactivity of teicoplanin should be monitored.

Daptomycin Use After Vancomycin-Induced Neutropenia in a Patient with Left-Sided Endocarditis

Objective:

To report a positive outcome in a patient treated with daptomycin for left-sided endocarditis associated with methicillin-resistant Staphylococcus aureus (MRSA) subsequent to vancomycin-induced neutropenia.

Case Summary:

A 55-year-old African American male was diagnosed with left-sided endocarditis, brain abscesses, and septic arthritis due to community-acquired MRSA. He began treatment with intravenous vancomycin to achieve a trough concentration of 15–20 μg/mL and oral rifampin 600 mg/day. A repair and resection of the mitral valve was completed on day 15 of hospitalization. Vancomycin was discontinued on day 36 secondary to drug-induced neutropenia (absolute neutrophil count nadir 162 cells/μL). Intravenous therapy with daptomycin 6 mg/kg every 24 hours was then initiated and the neutropenia resolved. The patient was discharged from the hospital on day 56.

Discussion:

Upon discontinuation of vancomycin, treatment options were limited to a small number of alternatives. Documented clinical experience and relevant studies are limited regarding the use of quinupristin/dalfopristin (Q/D), linezolid, trimethoprim/sulfamethoxazole (TMP/SMX), and daptomycin for the treatment of MRSA left-sided endocarditis. Daptomycin was selected because of its bactericidal qualities and its recent approval for this indication. The prognostic outlook for use of daptomycin in this treatment was uncertain; however, Q/D, linezolid, and TMP/SMX posed greater risks of failure.

Conclusions:

Treatment of MRSA left-sided endocarditis in patients intolerant to vancomycin is challenging. The positive outcome in our patient is likely attributable to aggressive vancomycin dosing and extended duration of treatment prior to the initiation of daptomycin. The use of daptomycin in this case enabled successful management of left-sided endocarditis.

A Case of Teicoplanin-Induced Pancytopenia Caused by Excessive Dosing

Teicoplanin is reported to be as effective as vancomycin but with minimal side effects. We report a case of teicoplanin-induced pancytopenia, which has not been demonstrated previously. A 44-year-old man with tetraplegia was treated with a diagnosis of urinary tract infection and pneumonia, and a high-dose of teicoplanin (400 mg every 12 hours) was administered for 4 days inadvertently. Although the infection rapidly improved, the patient developed pancytopenia by the fourth day of teicoplanin therapy, which was improved after reducing the dose of teicoplanin (200 mg/d). Our patient represents a probable case of teicoplanin-induced pancytopenia with adverse drug reaction probability score of 6.

Vancomycin-induced neutropenia: is it dose- or duration-related?

OBJECTIVE

To systematically evaluate the literature to determine whether vancomycin-induced neutropenia is dose- or duration-related and provide clinicians with feasible treatment alternatives.

DATA SOURCES

A literature search of PubMed (1949-November 2010), MEDLINE (1950-November 2010), EMBASE (1980-November 2010), and International Pharmaceutical Abstracts (1970-November 2010) was performed using the terms vancomycin, neutropenia, and leukopenia. Citations from publications were reviewed for additional references.

STUDY SELECTION AND DATA EXTRACTION

Studies and case reports were included if they reported neutropenia with vancomycin administration and excluded if they did not describe vancomycin dosages and/or concentrations, or if neutropenia resolved while the patient was still receiving vancomycin. Cases with significant confounders and those in which authors provided minimal information about patients were also excluded.

DATA SYNTHESIS

Seven retrospective chart reviews (ie, case series) and 33 case reports were identified. Of these, 3 retrospective reviews and 26 case reports met inclusion criteria. To our knowledge, no prospective studies have assessed this clinical complication. Data suggest that vancomycin-induced neutropenia may not be completely related to daily dosages, total cumulative dosage, or supratherapeutic vancomycin concentrations. Furthermore, evidence suggests that neutropenia is more likely associated with therapy longer than 7 days, with the majority of episodes occurring beyond 20 days of therapy. Given these findings, a practical approach is to monitor white blood cell (WBC) count with a differential (including absolute neutrophil count) once a week in patients who are receiving vancomycin for more than 7 days.

CONCLUSIONS

Vancomycin-induced neutropenia is most likely associated with prolonged vancomycin exposure. Patients receiving vancomycin for longer than 7 days should have WBC count, differential, monitored weekly. Vancomycin should be discontinued if there is a high clinical suspicion of it causing neutropenia, and an alternative agent should be initiated. Prospective case-controlled studies are needed to better characterize this adverse event.

Streptococcus agalactiae: a rare peritoneal infection in a continuous ambulatory peritoneal dialysis patient

Streptococcus agalactiae causes a rare and often fatal peritonitis in continuous ambulatory peritoneal dialysis (CAPD). A 52-year-old white female with Alport and chronic kidney disease was initiated on CAPD treatment. Nineteen months later she had a S. agalactiae peritonitis identified and received initially gentamicin-cephalothin, which was changed to ceftazidime, tobramycin, and vancomycin. Recovery started after peritoneal catheter removal. After 3 weeks, severe leucopenia occurred. Granulokine and steroids were given. Six weeks later, she felt well and an abdominal video laparoscopic procedure disclosed a diffuse peritoneal fibrosis, precluding CAPD resumption. She is now doing well on hemodialysis (HD).

Use of vancomycin pharmacokinetic-pharmacodynamic properties in the treatment of MRSA infections

Vancomycin is a commonly used antimicrobial in patients with methicillin-resistant Staphylococcus aureus (MRSA) infections. Increasing vancomycin MIC values in MRSA clinical isolates makes the optimization of vancomycin dosing pivotal to its continued use. Unfortunately, limited data exist regarding the optimal pharmacokinetic-pharmacodynamic (PK-PD) goal to improve bacterial killing and clinical outcomes with vancomycin. The hallmark study in this area suggests that achieving an AUC to MIC ratio of over 400 improves the likelihood of achieving these outcomes. Challenges in the implementation of PK-PD-based dosing for vancomycin include current methodologies utilized in microbiology laboratories, as well as intra- and interpatient pharmacokinetic variability. Individualized dosing based on MIC and specific patient factors is important to achieve optimal outcomes from vancomycin therapy.

Adverse events experienced by homecare patients: a scoping review of the literature

PURPOSE

The paper summarizes the results of a scoping review that focused on the occurrence of adverse events experienced by homecare patients.

DATA SOURCES

The literature search covered published and grey literature between 1998 and 2007. Databases searched included: MEDLINE, EMBASE, CINAHL and EBM REVIEWS including the Cochrane Library, AGELINE, the National Patient Safety Foundation Bibliography, Agency for Healthcare Research and Quality and the Patient Safety Net bibliography.

STUDY SELECTION

Papers included research studies, review articles, policy papers, opinion articles and legal briefs. Inclusion criteria were: (i) homecare directed services provided in the home by healthcare professionals or caregivers; (ii) addressed a characteristic relevant to patient experienced adverse events (e.g. occurrences, rates, definitions, prevention or outcomes); and (iii) were in English. Data extraction A pool of 1007 articles was reduced to 168 after analysis. Data were charted according to six categories: definitions, rates, causes, consequences, interventions and policy.

RESULTS

Eight categories emerged: adverse drug events, line-related, technology-related, infections and urinary catheters, wounds, falls, studies reporting multiple rates and other. Reported overall rates of adverse events ranged from 3.5 to 15.1% with higher rates for specific types. Few intervention studies were found. Adverse events were commonly associated with communication problems. Policy suggestions included the need to improve assessments, monitoring, education, coordination and communication.

CONCLUSION

A standardized definition of adverse events in the homecare setting is needed. Prospective cohort studies are needed to improve estimates and intervention studies should be undertaken to reduce the risk that homecare patients will experience adverse events.

Tolerability of teicoplanin in 117 hospitalized adults with previous vancomycin-induced fever, rash, or neutropenia: a retrospective chart review

BACKGROUND

Vancomycin has reliable antibacterial activity against many gram-positive pathogens but is associated with many adverse events. Teicoplanin, another glycopeptide, is associated with fewer adverse events, but its use in patients with previous vancomycin-induced adverse reactions remains controversial.

OBJECTIVES

The aims of this work were to evaluate the clinical characteristics of hospitalized patients with vancomycin-induced fever (ie, drug fever), rash, or neutropenia and to examine the tolerability of teicoplanin in these patients.

METHODS

This was a retrospective review of the medical charts of patients aged >or=18 years who were hospitalized between January 2002 and October 2007 at National Cheng Kung University Hospital in Tainan, Taiwan. Patients were included if they experienced drug-induced fever (ie, "drug fever"), rash, or neutropenia during vancomycin treatment. Their antimicrobial therapy was subsequently switched to teicoplanin. Clinical information and the development of drug fever, rash, or neutropenia with teicoplanin were determined from the charts.

RESULTS

Antibiotic therapy was switched to teicoplanin in 117 patients with vancomycin-induced fever alone (n = 24), rash alone (n = 77), both drug fever and rash (n = 8), or neutropenia (n = 8). The mean (SD) age of these patients was 53.1 (22.8) years, and 65 (56%) were male. The major clinical indications for vancomycin therapy among these patients were wound infections (21%), respiratory tract infections (14%), and bacteremia (13%). The dosages for vancomycin ranged from 1 g every 5 days to 1 g BID, and for teicoplanin ranged from 400 mg daily to 400 mg q72h, adjusted by the degree of renal dysfunction. Overall, 12 patients with vancomycin-induced fever (n = 2), rash (n = 6), or neutropenia (n = 4) subsequently developed teicoplanin-induced fever (n = 3), rash (n = 3), or neutropenia (n = 6). Specifically, of 8 patients with vancomycin-induced neutropenia, 4 (50%) subsequently developed neutropenia after switching to teicoplanin. Vancomycin- and teicoplanin-induced neutropenia was often noted after 1 week of treatment. Among patients with vancomycin-induced fever, rash, or neutropenia, there were no differences between patients with or without teicoplanin-induced fever, rash, or neutropenia in terms of age, sex, weight, dosage or duration of vancomycin therapy, dosage of teicoplanin, or underlying disease. There was no difference in mortality rates between patients with or without teicoplanin-induced fever, rash, or neutropenia. The cause of all deaths was progression of infectious or underlying disease, unrelated to vancomycin or teicoplanin use.

CONCLUSIONS

Based on this retrospective chart review of hospitalized patients with vancomycin-induced fever, rash, or neutropenia, only 10% experienced subsequent teicoplanin-induced fever, rash, or neutropenia. However, it should be noted that half of the patients with vancomycin-induced neutropenia developed teicoplanin-induced neutropenia.

Community-acquired methicillin-resistant Staphylococcus aureus mycotic aneurysm

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) continues to emerge as a cause of serious infections. We present the first case of abdominal mycotic aneurysm caused by Panton-Valentine leukocidin-positive CA-MRSA. This case adds another presentation to the clinical spectrum of CA-MRSA infections, and highlights the problem encountered in the choice of the therapy of serious community-acquired infections in an era of increasing CA-MRSA infections.

Cephalosporin-induced leukopenia following rechallenge with cefoxitin

OBJECTIVE

To describe a case of cefazolin-induced leukopenia in a critically ill patient who developed this adverse reaction upon rechallenge with cefoxitin.

CASE SUMMARY

A 22-year-old male was admitted after a motor vehicle crash. beta-Lactam therapy was initiated with vancomycin, cefepime, and metronidazole and, upon identification of methicillin-sensitive Staphylococcus aureus bacteremia 4 days later, therapy was narrowed to cefazolin 1 g every 12 hours. The dose was adjusted to 1 g every 12 hours during continuous venovenous hemodialysis. Imipenem was given for 2 days, resulting in a total of 18 days of beta-lactam treatment, at which time he developed significant leukopenia (white blood cell [WBC] count 0.9 x 10(3)/microL). Antimicrobial treatment was changed to tigecycline and continued for suspected pleural space infection. The patient's WBC count recovered within 4 days after the change in therapy. He was taken to surgery 8 days after cefazolin was discontinued and received perioperative prophylaxis with cefoxitin (total dose 3 g). Subsequently, the patient again became severely leukopenic (WBC count 2.4 x 10(3)/microL). Within a week after surgery, the patient developed septic shock secondary to multidrug-resistant Escherichia coli bacteremia and died.

DISCUSSION

beta-Lactam-induced leukopenia is a rare but well-described adverse drug reaction. It is a cumulative dose-dependent phenomenon reported to occur most often after 2 weeks of therapy. The mechanism of leukopenia is thought to be secondary to either an immune-mediated response or direct bone marrow toxicity. Rechallenge with a different beta-lactam antibiotic has not been shown to consistently cause recurrent leukopenia. The case described here suggests an immune-related mechanism for the development of leukopenia. Use of the Naranjo probability scale determined the association between cephalosporin use and leukopenia to be probable.

CONCLUSIONS

Cefazolin was a probable cause of this patient's leukopenia. It is important for clinicians to recognize beta-lactam-induced leukopenia and maybe recommend use of a drug from a different antibiotic class if continued treatment is indicated.

Optimizing antimicrobial therapy for gram-positive bloodstream infections in patients on hemodialysis

Infections with gram-positive organisms are highly prevalent in hemodialysis patients and are a major cause of morbidity and mortality in this population. Antimicrobial therapy is widely used to treat these infections, and prolonged therapy with these agents is often necessary. Extensive use of antimicrobials in hemodialysis patients has resulted in a growing threat of resistance, especially among gram-positive bacteria such as Enterococcus spp and Staphylococcus aureus. Vancomycin-resistant enterococci and S. aureus isolates with reduced susceptibility to vancomycin are increasingly being reported in hemodialysis patients. Additionally, resistance of these organisms to newer agents, such as linezolid and daptomycin, has been documented. Appropriate utilization of antimicrobial therapy to treat these organisms requires an understanding of the pharmacokinetic and pharmacodynamic principles to optimize therapy and avoid adverse drug events. The pharmacokinetic and pharmacodynamic profile of antimicrobial agents can be significantly altered in patients with chronic kidney disease. This review will describe mechanisms of antimicrobial resistance among common gram-positive organisms. The pharmacokinetic and pharmacodynamic principles of cephalosporins, vancomycin, aminoglycosides, linezolid, and daptomycin and applications for use of these agents in the treatment of patients with bloodstream infections on hemodialysis are discussed.