Piperacillin and vancomycin induced severe thrombocytopenia in a hospitalized patient

Piperacillin/tazobactam-induced sudden severe thrombocytopenia in a patient with a pressure ulcer: a case report

The standard treatment for an infected pressure ulcer (PU) with osteomyelitis is debridement, wound coverage and antibiotic administration. However, systemic administration of antibiotics in patients with osteomyelitis is controversial, and the optimal treatment duration for chronic osteomyelitis has not been standardised. We report a case of sudden severe thrombocytopenia induced by piperacillin/tazobactam (PIPC/TAZ) in a patient with PU-related osteomyelitis. A 57-year-old male patient with paraplegia, using a wheelchair full-time, presented to our plastic surgery department with infection of a stage IV hard-to-heal ischial PU. We surgically debrided the necrotising tissue and raised an ipsilateral biceps femoris musculocutaneous propeller flap for wound coverage. Polymicrobial infections, including Pseudomonas aeruginosa, were detected in the bone biopsy sample; therefore, systemic PIPC/TAZ was administered for the osteomyelitis. Unexpectedly, during the next 12 days of antibiotic administration, the patient's platelet count acutely dropped to 1×103/μl over three days. Based on a series of examinations, PIPC/TAZ was suspected to be the most likely cause of the severe thrombocytopenia. After drug discontinuation, the thrombocytopenia gradually improved. PIPC/TAZ is one of the most widely used antibiotic combinations in the plastic surgery field; it is conventionally administered for hard-to-heal wounds such as PUs and diabetic foot. The present case suggests that surgeons must take special precautions for patients undergoing PIPC/TAZ treatment. In this report, PIPC/TAZ-induced thrombocytopenia and the efficacy of antibiotic treatment for PU-related osteomyelitis are discussed in light of the available literature.

Zosyn-Induced Rapid Thrombocytopenia in a Patient With End-Stage Renal Disease and HIV: A Case Report

Thrombocytopenia is a rare but potentially serious complication associated with the use of various medications, including antibiotics. Piperacillin-tazobactam (Zosyn), a commonly used broad-spectrum antibiotic, has been reported as an infrequent cause of drug-induced thrombocytopenia. We present a case of a 65-year-old female with end-stage renal disease (ESRD) on hemodialysis, HIV, and multiple comorbidities who developed rapid-onset thrombocytopenia shortly after receiving Zosyn. The patient's platelet count dropped from a baseline of 291,000/μL on admission to a nadir of 8,000/μL within 36 hours of starting Zosyn. The administration of Zosyn was promptly discontinued, and the patient's platelet count gradually increased to 134,000/μL within two days after discontinuation. The patient had no apparent bleeding manifestations during her hospital stay. Further workup for other causes of thrombocytopenia, including heparin-induced thrombocytopenia (HIT), was negative. This case highlights the importance of vigilance for drug-induced thrombocytopenia in patients receiving Zosyn and the need for prompt recognition and management to prevent potential complications.

Vancomycin-Induced Thrombocytopenia in a 35-Year-Old Female With Pneumonia: A Case Report

Vancomycin is one of the most empirically used antibiotics in severely ill patients in hospitalized settings. Vancomycin-induced thrombocytopenia (VITP) is a rare and potentially life-threatening complication that requires immediate recognition. Platelet destruction is largely immune-mediated and results in a precipitous drop in the platelet count over a short period of time. Most cases of VITP are drug-dependent, as discontinuation of the offending agent frequently results in a timely return to baseline to pre-exposure platelet levels. Here, we present a case of severe vancomycin-induced thrombocytopenia in a 35-year-old female with a history of multiple comorbidities who presented with pneumonia. She was undergoing treatment with vancomycin and piperacillin-tazobactam and developed thrombocytopenia within 24 hours of hospitalization. The patient was on a loading dose of 1250 mg intravenous vancomycin every 24 hours and piperacillin-tazobactam 3.375 g intravenously every six hours for presumed community-acquired pneumonia. Her other medications included ondansetron, bupropion, sertraline, tamsulosin, pantoprazole, ergocalciferol, and insulin glargine. Additionally, the patient was placed on a prophylactic dose of enoxaparin while in-patient. The patient's thrombocytopenia resolved with discontinuation of vancomycin. Clinicians should be well-informed about which medications can trigger thrombocytopenia whenever starting a medication in such cases.

Immune Thrombocytopenia: A Rare Adverse Event of Vancomycin Therapy

Vancomycin, a glycopeptide antibiotic, is widely used for Gram-positive cocci or bacilli bacteria-induced serious infections. Although considered safe and effective, it still causes adverse events. Vancomycin-induced immune thrombocytopenia is a rarely reported adverse event, manifesting from asymptomatic thrombocytopenia to life-threatening bleeding. We underline a case of a 56-year-old male with a diabetic foot with an infected exudating purulent ulcer. He experienced a significant drop in platelet count after commencing vancomycin, and discontinuing vancomycin resulted in improved platelet count with positive vancomycin-induced anti-platelet antibodies. After ruling out other possible causes of thrombocytopenia, a presumptive diagnosis of vancomycin-induced thrombocytopenia was made.

Is Piperacillin-Tazobactam an Appropriate Empirical Agent for Hospital-Acquired Sepsis and Community-Acquired Septic Shock of Unknown Origin in Australia?

Early appropriate empirical antibiotics are critical for reducing mortality in sepsis. For hospital-acquired sepsis of unknown origin in Australia, piperacillin-tazobactam (TZP) is recommended as an empirical therapy. Anecdotally, some institutions also use TZP for community-acquired septic shock. This narrative review aimed to scrutinise the appropriateness of TZP as an empirical agent for undifferentiated hospital-acquired sepsis and community-acquired septic shock. An online database (Medline) was searched for relevant studies in adults published in the last 10 years. Studies were included if they addressed separately reported clinical outcomes related to a relevant aspect of TZP therapy in sepsis. Of 290 search results, no studies directly addressed the study aim. This review therefore explores several themes that emerged from the contemporary literature, all of which must be considered to fully interrogate the appropriateness of TZP use in this context. This review reveals the paucity and low quality of evidence available for TZP use in sepsis of unclear origin, while demonstrating the urgent need and equipoise for an Australian audit of TZP use in patients with sepsis of unknown origin.

A Rare Case of Rapid Onset Thrombocytopenia Induced by Piperacillin/Tazobactam in a Liver Transplant Recipient

Drug-induced thrombocytopenia is a relatively common clinical condition. However, acute thrombocytopenia after initiation of piperacillin/tazobactam is rare, with only a few cases reported in the literature. The mechanism by which it happens is still unclear but it is thought to be immune-mediated. We present the first case of rapid-onset thrombocytopenia induced by piperacillin/tazobactam in a liver transplant recipient. Our patient had previous exposure to the antibiotic, and thrombocytopenia was treated by merely stopping the culprit antibiotic (piperacillin/tazobactam). The patient had a successful challenge with cefepime afterward despite possible cross-reactivity, making this the second case report of successful re-challenging with cefepime.

Vancomycin-induced thrombocytopenia in endocarditis: A case report and review of literature

BACKGROUND

Thrombocytopenia is a serious complication in the medical practice of numerous drugs. Vancomycin is frequently used for the prophylaxis and treatment of suspected or identified methicillin-resistant positive infections. Several cases with vancomycin-induced thrombocytopenia (VIT) have been reported. However, these have rarely been extensively reviewed. The present report describes a case of VIT in endocarditis, and reviews all VIT cases reported in the literature.

CASE SUMMARY

A 26-year-old male diagnosed with infective endocarditis was admitted. The patient was treated with multiple drugs, including vancomycin, which was initially intravenously given at 1000 mg every 12 h and subsequently at 500 mg every 8 h on day 3. On day 11, the platelet count decreased to 51 × 10⁹/L, vancomycin was switched to 500 mg every 12 h, and platelet transfusion was given. On day 17, the platelet count dropped to 27 × 10⁹/L, and platelet transfusion was administered again. On day 23, vancomycin was adjusted to 500 mg every 8 h as the trough concentration dropped to the minimum effective concentration. On day 33, the platelet count declined to approximately 40 × 10⁹/L. After platelet transfusion, the platelet count rebounded to 90 × 10⁹/L on day 35 but dropped again to 42 × 10⁹/L on day 43. Based on the time-to-platelet count curve and Naranjo’s Adverse Drug Reaction Probability Scale score, VIT was suspected. After vancomycin discontinuation and platelet transfusion, the platelet count gradually normalized.

CONCLUSION

The diagnosis of VIT can be achieved through the time-to-platelet count curve and Naranjo’s Adverse Drug Reaction Probability Scale score. The platelet count cannot be normalized simply by platelet transfusion alone, and vancomycin discontinuation is essential.

Hematologic adverse effects induced by piperacillin-tazobactam: a systematic review of case reports

Background Piperacillin/tazobactam, a semisynthetic antibiotic, is widely used to treat polymicrobial infections. Its hematologic adverse reactions are rare and the severity can be mild to life-threatening. To our knowledge, there has not been a publication reviewing hematologic abnormalities attributable to piperacillin/tazobactam. Aim of the review To evaluate the characteristic, clinical identification, mechanism and treatment of the hematologic toxicity caused by piperacillin/tazobactam. Method A search of Medline and Embase electronic databases was performed for case reports of adverse reactions of hematologic system related to piperacillin/tazobactam from inception to December 2018. Statistical analysis of demographic, clinical features, laboratory Indexes and treatments was performed using Microsoft EXCEL 2007. Results Fifty-nine references were obtained involving 62 patients. The adverse drug reactions were mainly hemolytic anemia (25, 40.3%), thrombocytopenia (23, 37.1%), and neutropenia (12, 19.4%), which might be accompanied by some typical symptoms. Hemolytic anemia or thrombocytopenia was generally believed to be immune-mediated and often appeared within 10 days, and neutropenia was thought to be related to bone marrow suppression and usually occurred 2 weeks after the initiation of piperacillin/tazobactam. Most patients improved or recovered within a week with treatment or not, and fewer high-quality evidence-based treatments were identified. Conclusion Although part of the patients have clinical symptom, the hematologic adverse drug reactions of piperacillin/tazobactam are easily overlooked or misdiagnosed. Take special caution for patients with prolonged piperacillin/tazobactam treatment or specific disease, and prompt recognition and treatment of the adverse drug reactions are essential and can hasten recovery regardless of the type of side reactions.

Antimicrobial-Induced Cytopenia and Bone Marrow Hypocellularity in Patients with Cirrhosis

There is great variation in cytopenias in cirrhotic patients with same severity and hypersplenism and their causative factors are not clear. Recent studies have highlighted the role of gut microbiome in regulation of constant and emergency hematopoiesis. Broad-spectrum antibiotics can disrupt the homeostatic or adaptive microbiota in cirrhosis, leading to impaired hematopoiesis and a higher susceptibility to infections. We studied all patients with cirrhosis with cytopenia (anemia, leucopenia, and/or thrombocytopenia), admitted in the Institute of Liver & Biliary Sciences, between January 2016 and July 2017, who underwent a bone marrow examination. The effect of the different antimicrobial agents on peripheral blood counts and bone marrow cellularity was assessed. A total of 196 patients' data was analyzed for this study. Patients on antimicrobials (n = 115) had significantly lower hemoglobin (p < 0.001), total leucocyte count (p = 0.048), and platelet count (p = 0.043) compared to patients not on antimicrobials. On unadjusted analysis, significant association with thrombocytopenia existed in beta-lactams (OR = 1.56, 95% CI = 1.06–2.40), quinolones (OR = 1.66, 95% CI = 1.11–2.61), and antifungals (OR = 2.24, 95% CI = 1.96–4.34). Cephalosporins were found to be significantly associated with anemia (OR = 1.91, 95% CI = 1.07–3.41). Patients who received antimicrobials had hypocellular marrow (p < 0.001) as compared to nonrecipients of antibiotics. The adjusted analysis showed that quinolones and beta-lactam antibiotics are the drug classes having significant association with thrombocytopenia and alternative class of drug should be explored in these patients to avoid severe thrombocytopenia.

A patient with oxaliplatin immune-induced syndrome (OIIS) who also developed leucovorin and palonosetron-associated thrombocytopenia

OBJECTIVES

We report a case of an 83 year old man who developed oxaliplatin immune-induced syndrome (OIIS) after his 19th cycle of FOLFOX (5FU, leucovorin, oxaliplatin). When oxaliplatin was omitted from his next cycle of chemotherapy he continues to show signs of drug-induced immune thrombocytopenia (DITP) and was found to have drug-dependent, platelet-reactive antibodies (DDPA) to leucovorin and palonosetron as well as oxaliplatin.

METHODS

The patient was admitted for monitoring but required no transfusions and thrombocytopenia resolved without treatment during his first admission. Drug-dependent antibody testing was performed on his blood by the Blood Center of Wisconsin (Diagnostic Laboratories; Milwaukee, WI).

RESULTS

No RBC or platelet IgG or IgM antibodies were detected in the absence of any drugs, but upon addition of palonosetron, leucovorin, or oxaliplatin, the tests became strongly positive for anti-RBC IgG and anti-platelet IgG antibodies.

DISCUSSION

Repeated administration of oxaliplatin can result in drug-induced immune thrombocytopenia (DITP) or autoimmune hemolytic anemia (AIHA). This phenomenon has recently been termed OIIS and may additionally include Evan's syndrome or thrombotic microangiopathy (TMA). Here we describe a patient who developed OIIS with drug-dependent, platelet-reactive antibodies (DDPA) to leucovorin and palonosetron. To our knowledge, these two drugs have never been described in the literature as a cause of DDPA. We suggest that OIIS in addition to oxaliplatin-induced thrombocytopenia may be associated with the development of DDPAs to other drugs causing clinically significant thrombocytopenia which is important to recognize and manage with discontinuation of provoking agents.

Vancomycin-Induced Thrombocytopenia: A Narrative Review

Thrombocytopenia has been reported as an adverse reaction of numerous drugs. Vancomycin is often overlooked as a culprit but has been associated with several cases of thrombocytopenia that were not well described in the literature. A literature search was conducted to find reports of thrombocytopenia induced by vancomycin. Biomedical databases including 'PubMed', 'Scopus', and 'Web of Science' were searched using terms 'vancomycin', 'platelet', 'pancytopenia', 'thrombocytopenia', and 'bleeding'. English language articles published before July 2015 were included. Thirty-nine papers including 29 case reports (30 cases), five observational studies, two clinical trials, two letters, and one case series remained for final analysis. The main route of administration was intravenous infusion. This adverse reaction seems to be duration dependent with the mean time to platelet nadir count of 8 days in reported cases. The interval may be significantly shorter in re-exposure to the drug. Platelet nadir counts ranged from 2000 to 100,000/mL in patients who experienced bleeding. Vancomycin-specific antibodies were detected in 13 of 17 patients who were tested in the case reports. Based on the Naranjo Adverse Drug Reaction Probability Scale, reaction was 'definite', 'probable', and 'possible' in 1, 15, and 14 patients, respectively. Among 30 cases, vancomycin was discontinued in 29 patients and platelets returned to normal counts within 5-6 days in 17 of them; in one patient, vancomycin was not discontinued, but platelet count recovered 11 days after the nadir time. Transfusion might be recommended if severe thrombocytopenia and bleeding occurs. Intravenous immunoglobulins, corticosteroids, rituximab, and plasma exchange should be reserved for patients with resistant thrombocytopenia and severe bleeding as mentioned in a number of reports.

Piperacillin/tazobactam-induced immune-mediated thrombocytopenia in the intensive care unit

WHAT IS KNOWN AND OBJECTIVE

Drug-induced immune-mediated thrombocytopenia is a rare adverse event that remains a diagnostic challenge, especially in the critically ill population. There are only two previously reported cases of rapid and profound thrombocytopenia after administration of piperacillin/tazobactam.

CASE SUMMARY

A 64-year-old man experienced several episodes of isolated thrombocytopenia after receiving piperacillin/tazobactam. Interestingly, the degree of thrombocytopenia varied with the amount of corticosteroid therapy the patient was receiving. Due to the complexity of thrombocytopenia in critically ill patients, other potential causes were extensively worked up and ruled out.

WHAT IS NEW AND CONCLUSION

We describe the first case of piperacillin/tazobactam-induced immune-mediated thrombocytopenia that was mitigated by the administration of corticosteroid therapy. This case highlights the importance of identifying potential drug-related causes of isolated thrombocytopenia.

Rapid-Onset Thrombocytopenia Following Piperacillin-Tazobactam Reexposure

Drug-induced thrombocytopenia is a rare but serious adverse event that has been associated with multiple drugs including β-lactams. Although it mostly occurs with prolonged medication use, some cases of rapid-onset thrombocytopenia have been reported. We describe the case of a 69-year-old man who developed severe and immediate thrombocytopenia following reexposure to piperacillin-tazobactam in the critical care setting. He received a 6-day course of piperacillin-tazobactam for a possible pneumonia immediately after cardiac surgery. During this course of therapy, his platelet count decreased (fluctuating between 69 × 10(3) /mm(3) and 104 × 10(3) /mm(3) ) and then progressively increased after completion of the antibiotic to 340 × 10(3) /mm(3) on postoperative day 15. Ten days after the antibiotic course was completed (postoperative day 16), the patient developed new signs of infection (fever and neutrophilia), and piperacillin-tazobactam was restarted. Eight hours after reintroducing the antibiotic, his platelet count dropped from 317 × 10(3) /mm(3) to 7 × 10(3) /mm(3) . After reviewing all the medications administered to the patient as well as other potential causes of thrombocytopenia, and given the chronology of events, piperacillin-tazobactam was suspected as the most likely offending agent and was therefore replaced by meropenem on postoperative day 17. The patient's platelet count began to rise 2 days after discontinuation of piperacillin-tazobactam and reached 245 × 10(3) /mm(3) by postoperative day 30. No spontaneous bleeding or thrombosis occurred while the patient was thrombocytopenic. Use of the Naranjo Adverse Drug Reaction Probability Scale indicated a probable relationship (score of 6) between the patient's development of thrombocytopenia and piperacillin-tazobactam therapy. This case highlights the severity and swiftness in which drug-induced thrombocytopenia may present in the context of cardiac surgery.

Tazobactam and piperacillin-induced thrombocytopenia: A case report

The present study reports a case of tazobactam and piperacillin (TZP)-induced thrombocytopenia in an elderly patient, from which complete clinical data and peripheral blood samples were collected. Platelet numbers were decreased 1 day following TZP treatment initiation; however, they were revealed to have increased 1–2 days following withdrawal of TZP, and had reached normal levels 3–5 days later. There was no evidence of bone marrow suppression, antibodies against peripheral plasma platelets were absent and levels of complement C3 were decreased. These results suggested that TZP was able to cause rapid and reversible thrombocytopenia, which was not associated with bone marrow suppression but may have involved activation of complement C3. The results of the present study therefore suggest that doctors should be aware of the risk of thrombocytopenia in patients treated with TZP.

Drug-induced immune-mediated thrombocytopenia in the intensive care unit

A 62-year-old woman with prosthetic mitral valve was admitted for explant of an infected prosthetic knee. Perioperatively, she was bridged with heparin and started on empiric vancomycin and piperacillin-tazobactam. Platelet counts dropped precipitously within 2 days reaching a nadir of 6000/μL, without any bleeding. Decline persisted despite substituting heparin with bivalirudin. Antiplatelet factor 4 and anti-PLA1 antigen were negative. Schistocytes were absent. Antibiotics were substituted with daptomycin for suspected drug-induced thrombocytopenia. Pulse dose of intravenous immunoglobulin was initiated with rapid normalization of platelet count. She tested positive for IgG antiplatelet antibodies to vancomycin and piperacillin-tazobactam thereby confirming the diagnosis. Drug-induced immune-mediated thrombocytopenia is an underrecognized cause of thrombocytopenia in the intensive care units. Clinicians should be cognizant of this entity, and a definitive diagnosis should be sought if feasible.

Life-threatening haematuria caused by vancomycin-induced thrombocytopenia

Thrombocytopenia is a rare side effect of vancomycin, an antibiotic that is often used to treat Gram-positive bacterial infections. A 67-year-old man developed bilateral pulmonary emboli and hospital-acquired pneumonia following left ureteric reimplantation. He was anticoagulated with rivaroxaban and started on intravenous vancomycin and gentamicin for treatment of pneumonia. After five doses of vancomycin, his platelet count dropped to a nadir of 0 × 10(9)/L (baseline: 314 × 10(9)/L) manifesting as visible heavy haematuria and haemodynamic instability due to excessive blood loss. Reversal of the thrombocytopenia was achieved with intravenous immunoglobulin, methylprednisolone and continuous platelet transfusions.

Rapid-onset piperacillin-tazobactam induced thrombocytopenia

Thrombocytopenia can occur from a variety of etiologies. Drug-induced thrombocytopenia is known to occur with beta-lactam medications, but often in the setting of prolonged use. We describe 2 patients who developed rapid-onset thrombocytopenia from piperacillin/tazobactam. Other causes of immediate thrombocytopenia were excluded. These cases describe a rare presentation of rapid-onset thrombocytopenia in a commonly used medication.

Amoxicillin/Clavulanic Acid-induced thrombocytopenia

INTRODUCTION AND OBJECTIVE

Drug-induced thrombocytopenia is a common adverse effect reported in the literature. Typically patients present with a low platelet count with signs and symptoms ranging from bruising to bleeding, and major organ damage. Penicillin-induced thrombocytopenia previously reported in the literature is explained primarily through the hapten-dependent antibody process. The goal of this report is to present a case of an amoxicillin/clavulanic acid-induced thrombocytopenia.

CASE PRESENTATION

A 23-year-old male presented to the emergency department with bruises on his arms and legs after completing a full course of amoxicillin/clavulanic acid of 625 mg twice a day for 5 days for tonsillitis. After several tests, the patient was diagnosed with thrombocytopenia induced by amoxicillin/clavulanic acid. The patient was treated with a corticosteroids taper regimen for 3 weeks. He was discharged after 3 days of inpatient treatment with instructions to avoid physical activity for 2 weeks. Two weeks post discharge, the follow-up showed that the platelet count had increased.

DISCUSSION

Penicillin-induced thrombocytopenia has been previously reported in the inpatient setting where bleeding was observed. However, the patient in this case report presented with bruises on his arms and legs. The diagnosis was made by the process of elimination; not all possible tests were conducted. The patient was prescribed corticosteroids that are not indicated for drug-induced thrombocytopenia. The Naranjo scale showed that this is a probable adverse event of amoxicillin/clavulanic acid.

CONCLUSION

This is a unique case where amoxicillin/clavulanic acid was reported to be a probable cause of thrombocytopenia in an outpatient setting without signs of bleeding and without concomitant medications.

The potential of antimicrobials to induce thrombocytopenia in critically ill patients: data from a randomized controlled trial

BACKGROUND

Antimicrobial-induced thrombocytopenia is frequently described in the literature among critically ill patients. Several antimicrobials have been implicated, although experimental evidence to demonstrate causality is limited. We report, using a randomized trial, the potential of antimicrobials to induce thrombocytopenia.

METHODS

Randomized trial allocated patients to antimicrobial treatment according to standard- of-care (SOC group) or drug-escalation in case of procalcitonin increases (high-exposure group). Patients were followed until death or day 28. Thrombocytopenia defined as absolute (platelet count ≤ 100 x 109/L) or relative (≥ 20% decrease in platelet count). Analyses were performed in the two randomized groups and as a merged cohort.

RESULTS

Of the 1147 patients with platelet data available, 18% had absolute thrombocytopenia within the first 24 hours after admission to intensive care unit and additional 17% developed this complication during follow-up; 57% developed relative thrombocytopenia during follow-up. Absolute and relative thrombocytopenia day 1-4 was associated with increased mortality (HR: 1.67 [95% CI: 1.30 to 2.14]; 1.71 [95% CI: 1.30 to 2.30], P<0.0001, respectively). Patients in the high-exposure group received more antimicrobials including piperacillin/tazobactam, meropenem and ciprofloxacin compared with the SOC group, whereas cefuroxime was used more frequently in the SOC group (p<0.05). Risk of absolute and relative thrombocytopenia (RR: 0.9 [0.7-1.3], p=0.7439; 1.2 [1.0-1.4], p=0.06; respectively), as well as absolute platelet count (daily difference, high-exposure vs. SOC -1.7 [-3.8-0.5], p=0.14) was comparable between groups. In observational analyses, use of ciprofloxacin and piperacillin/tazobactam predicted risk of relative thrombocytopenia (vs. cefuroxime, RR: 2.08 [1.48-2.92]; 1.44 [1.10-1.89], respectively), however only ciprofloxacin were associated with a reduction in absolute platelet count (p=0.0005).

CONCLUSION

High exposure to broad-spectrum antimicrobials does not result in a reduction in thrombocytopenia in critically ill patients. However, single use of ciprofloxacin, and less so piperacillin/tazobactam, may contribute to a lower platelet count.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00271752 http://clinicaltrials.gov/ct2/show/NCT00271752.

Underlying the mechanism of vancomycin and human serum albumin interaction: a biophysical study

In the present study, the binding mechanism of vancomycin with human serum albumin (HSA) was determined. Upon addition of vancomycin to HSA, the fluorescence emission was quenched and the binding constant of vancomycin with HSA was found to be 6.05 × 10(3) M(-1) at 295 K, which corresponds to -2.16 × 10(4) J·mol(-1) of free energy. The conformation of HSA was altered upon binding of vancomycin with a decrease in α helix and an increase in β sheets and random coils, suggesting partial unfolding of the secondary structure. Molecular docking experiments found that vancomycin binds strongly with HSA at the hydrophobic pocket through hydrogen bonding and van der Waals interactions. An average binding distance of 4.71 nm has been determined on the basis of the Förster resonance energy theory. It was demonstrated that vancomycin binding to HSA causes protein structural changes.

Piperacillin-induced thrombocytopenia reversed by high-flux hemodialysis in an uremic patient

Drug-induced thrombocytopenia in an infected patient often is overlooked. We present a 74-year-old uremic female with continuous renal replacement therapy developed severe thrombocytopenia during the treatment course of piperacillin/tazobactam. Platelet counts recovered rapidly after discontinuing piperacillin/tazobactam and receiving high-flux hemodialysis. The George criteria indicates piperacillin/tazobactam as the probable cause of thrombocytopenia in this patient. Immediate withdrawal of the causative drug is important for drug-induced thrombocytopenia. Prompt high-flux hemodialysis may be an adjunctive management for uremic patients.

Stimulation of platelet apoptosis by balhimycin

Glycopeptides, such as vancomycin, are powerful antibiotics against methicillin-resistant Staphylococcus aureus. Balhimycin, a glycopeptide antibiotic isolated from Amycolatopsis balhimycina, is similarly effective as vancomycin. Side effects of vancomycin include triggering of platelet apoptosis, which is characterized by cell shrinkage and by cell membrane scrambling with phosphatidylserine exposure at the cell surface. Stimulation of apoptosis may involve increase of cytosolic Ca(2+) activity, ceramide formation, mitochondrial depolarization and/or caspase activation. An effect of balhimycin on apoptosis has, however, never been reported. The present study thus tested whether balhimycin triggers platelet apoptosis. Human blood platelets were treated with balhimycin and cell volume was estimated from forward scatter, phosphatidylserine exposure from annexin V-binding, cytosolic Ca(2+) activity from fluo-3AM fluorescence, ceramide formation utilizing antibodies, mitochondrial potential from DiOC6 fluorescence, and caspase-3 activity utilizing antibodies. As a result, a 30 min exposure to balhimycin significantly decreased cell volume (≥1 μg/ml), triggered annexin V binding (≥1 μg/ml), increased cytosolic Ca(2+) activity (≥1 μg/ml), stimulated ceramide formation (≥10 μg/ml), depolarized mitochondria (≥1 μg/ml) and activated caspase-3 (≥1 μg/ml). Cell membrane scrambling and caspase-3 activation were virtually abrogated by removal of extracellular Ca(2+). Cell membrane scrambling was not significantly blunted by pancaspase inhibition with zVAD-FMK (1μM). In conclusion, balhimycin triggers cell membrane scrambling of platelets, an effect dependent on Ca(2+), but not on activation of caspases.

Piperacillin/tazobactam induced thrombocytopaenia--a delayed response

A 48-year-old lady who presented with sepsis secondary to a pelvi-ureteric junction obstruction was treated with an extended course of piperacillin/tazobactam. Four days after completing the course she developed thrombocytopaenia. Intravenous immunoglobulin was required to bring her platelet count back to normal. In the absence of other causes the authors believe that a delayed reaction to piperacillin/tazobactam was the cause of her thrombocytopaenia.

A Case of Thrombocytopenia due to Odontogenic Infection

Thrombocytopenia in surgical patients is a potentially serious condition,faced by surgeons. A close relationship between sepsis and thrombocytopenia has been suggested. Thrombocytopenia has even been suggested to be indicative of an acute infection. Platelet count in a septicemic patient may also serve as a prognostic tool. There are many reports of thrombocy-topenia due to septicemia in the literature but the occurrence of thrombocytopenia in maxillofacial infections is rare. Thrombocytopenia in a patient with odontogenic infection presents unique diagnostic and management challenges. A case report of an adult male patient with odontogenic infection, who developed life-threatening thrombocytopenia, is presented.

A bibliometric study of the use of the classification and diagnostic systems in psychiatry over the last 25 years

BACKGROUND

Our purpose was to examine the use of classification and diagnostic systems in the field of psychiatry (CDSP) from a bibliometric perspective, over the period 1980-2005.

METHODS

We selected (in EMBASE and MEDLINE databases) documents that contained, in any of their sections, the descriptors 'psychiatr*', 'DSM*', 'ICD*', or 'diagnostic criteria',as well as other more specific descriptors. As a bibliometric indicator of production we applied Price's law. We also calculated the national participation index (PI) and correlated it with overall PI in biomedical and health sciences, and with PI in the discipline of psychiatry.

RESULTS

We obtained 20,564 original documents; 15,743 referred to the Diagnostic and Statistical Manual of Mental Disorders (DSM) and 3,106 to the International Classification of Diseases (ICD). Our results indicate non-fulfilment of Price's law, since scientific production on CDSP does not undergo exponential growth (correlation coefficient r = 0.9651, vs. r = 0.9927 after linear adjustment). Of the 10 journals with the highest impact factor in the field of psychiatry, the Journal of Clinical Psychiatry has the highest PI in the DSM subgroup (PI = 14.77), and the British Journal of Psychiatry in the ICD subgroup (PI = 1.54). The principal producer country is the United States (PI = 37.9), though in proportion to its production in the psychiatric field the ranking is headed by Finland. Only 10 countries, of the 20 major producers in health sciences, surpass their own PI in the field of psychiatry (Brazil, Italy, Japan, Austria, Spain, Germany, France, India, Switzerland, and China).

CONCLUSIONS

Over recent years, the use of CDSP (basically the DSM or ICD) in the scientific literature has increased. Nevertheless, the abstracts to these studies, included in the principal databases, should always specify the diagnostic criteria employed, with a view to increasing information levels and reliability for the reader.