A controlled trial of aerosolized pentamidine or trimethoprim-sulfamethoxazole as primary prophylaxis against Pneumocystis carinii pneumonia in patients with human immunodeficiency virus infection. The Dutch AIDS Treatment Group

Comparative efficacy and safety of Pneumocystis jirovecii pneumonia prophylaxis regimens for people living with HIV: a systematic review and network meta-analysis of randomized controlled trials

BACKGROUND

Pneumocystis jirovecii pneumonia (PCP) is a common opportunistic infection among people living with HIV (PWH), particularly among new and untreated cases. Several regimens are available for the prophylaxis of PCP, including trimethoprim-sulfamethoxazole (TMP-SMX), dapsone-based regimens (DBRs), aerosolized pentamidine (AP), and atovaquone.

OBJECTIVES

To compare the efficacy and safety of PCP prophylaxis regimens in PWH by network meta-analysis.

METHODS

DATA SOURCES: Embase, MEDLINE, and CENTRAL from inception to June 21, 2023.

STUDY ELIGIBILITY CRITERIA

Comparative randomized controlled trials (RCTs).

PARTICIPANTS

PWH.

INTERVENTIONS

Regimens for PCP prophylaxis either compared head-to-head or versus no treatment/placebo.

ASSESSMENT OF RISK OF BIAS

Cochrane risk-of-bias tool for RCTs 2.

METHODS OF DATA SYNTHESIS

Title or abstract and full-text screening and data extraction were performed in duplicate by two independent reviewers. Data on PCP incidence, all-cause mortality, and discontinuation due to toxicity were pooled and ranked by network meta-analysis. Subgroup analyses of primary versus secondary prophylaxis, by year, and by dosage were performed.

RESULTS

A total of 26 RCTs, comprising 55 treatment arms involving 7516 PWH were included. For the prevention of PCP, TMP-SMX was ranked the most favourable agent and was superior to DBRs (risk ratio [RR] = 0.54; 95% CI, 0.36-0.83) and AP (RR = 0.53; 95% CI, 0.36-0.77). TMP-SMX was also the only agent with a mortality benefit compared with no treatment/placebo (RR = 0.79; 95% CI, 0.64-0.98). However, TMP-SMX was also ranked as the most toxic agent with a greater risk of discontinuation than DBRs (RR = 1.25; 95% CI, 1.01-1.54) and AP (7.20; 95% CI, 5.37-9.66). No significant differences in PCP prevention or mortality were detected among the other regimens. The findings remained consistent within subgroups.

CONCLUSIONS

TMP-SMX is the most effective agent for PCP prophylaxis in PWH and the only agent to confer a mortality benefit; consequently, it should continue to be recommended as the first-line agent. Further studies are necessary to determine the optimal dosing of TMP-SMX to maximize efficacy and minimize toxicity.

Nebulised pentamidine prophylaxis of pneumocystis pneumonia in adults accessing HIV services at royal free hospital, London

Receipt of nebulised pentamidine in people with HIV was audited to identify if individuals were appropriately receiving nebulised pentamidine, and whether national guidelines were being followed when prophylaxis was commenced and discontinued. Of 76 people with who received nebulised pentamidine, the main indication for starting nebulised pentamidine was a co-trimoxazole adverse drug reaction. Co-trimoxazole desensitization was not attempted before starting nebulised pentamidine. The main indication for stopping nebulised pentamidine prophylaxis was when immune reconstitution occurred. This single centre audit revealed that national guidelines were being followed in most cases. The lack of information regarding the reason for starting or stopping nebulised pentamidine prophylaxis, or detail of the clinician's concerns about potential poor adherence with oral regimens of prophylaxis as a reason for choosing nebulised pentamidine prophylaxis, identifies a need for improved documentation of clinicians' decision-making. Introduction of pharmacist-led interventions/alerts using patients' electronic records, similar to those used in primary care, would enable the specialist pharmacy team to identify when and if co-trimoxazole desensitization has been offered and discussed/declined before a clinician prescribes nebulised pentamidine as well as enabling identification of those in who pentamidine prophylaxis has been continued, despite "immune reconstitution".

Pneumocystis jirovecii pneumonia in people living with HIV: a review

Pneumocystis jirovecii is a ubiquitous opportunistic fungus that can cause life-threatening pneumonia. People with HIV (PWH) who have low CD4 counts are one of the populations at the greatest risk of Pneumocystis jirovecii pneumonia (PCP). While guidelines have approached the diagnosis, prophylaxis, and management of PCP, the numerous studies of PCP in PWH are dominated by the 1980s and 1990s. As such, most studies have included younger male populations, despite PCP affecting both sexes and a broad age range. Many studies have been small and observational in nature, with an overall lack of randomized controlled trials. In many jurisdictions, and especially in low- and middle-income countries, the diagnosis can be challenging due to lack of access to advanced and/or invasive diagnostics. Worldwide, most patients will be treated with 21 days of high-dose trimethoprim sulfamethoxazole, although both the dose and the duration are primarily based on historical practice. Whether treatment with a lower dose is as effective and less toxic is gaining interest based on observational studies. Similarly, a 21-day tapering regimen of prednisone is used for patients with more severe disease, yet other doses, other steroids, or shorter durations of treatment with corticosteroids have not been evaluated. Now with the widespread availability of antiretroviral therapy, improved and less invasive PCP diagnostic techniques, and interest in novel treatment strategies, this review consolidates the scientific body of literature on the diagnosis and management of PCP in PWH, as well as identifies areas in need of more study and thoughtfully designed clinical trials.

Effect of Pneumocystis jirovecii pneumonia prophylaxis on hematologic toxicity in patients receiving chemoradiation for primary brain tumors

PURPOSE

Diffuse gliomas are managed with radiation and temozolomide; however, this therapy often results in hematologic toxicities. Patients undergoing chemoradiation also risk contracting Pneumocystis jirovecii pneumonia (PJP), and frequently receive prophylaxis against PJP during treatment. Independent of chemoradiation, some PJP prophylaxis drugs have the potential to cause myelosuppression, which could require cessation of chemotherapy. Here, we evaluate differences in the frequency of hematologic toxicities during chemoradiation when patients receive PJP prophylaxis.

METHODS

This retrospective chart review evaluated patients with primary brain tumors treated with radiation and concurrent temozolomide. Analyses were performed to assess the effect of the type of PJP prophylaxis on risk for neutropenia, lymphopenia, or thrombocytopenia and the severity of these adverse effects as defined using the Common Terminology Criteria for Adverse Events.

RESULTS

Of the 217 patients included in this analysis, 144 received trimethoprim-sulfamethoxazole (TMP/SMX) and 69 received pentamidine. Of the patients who received TMP/SMX, 15.3% developed an absolute neutrophil count < 1500 cells/µL compared with 7.2% of patients receiving pentamidine (p = 0.10). Platelet count < 100,000/µL occurred in 18.1% of patients who received TMP/SMX and 20.3% of patients who received pentamidine (p = 0.70). No significant differences in lymphocyte counts between therapies were seen. Severity of hematologic toxicities were similar between PJP prophylaxis groups.

CONCLUSION

These findings suggest that the type of PJP prophylaxis does not significantly affect the risk for hematologic toxicity in brain tumor patients receiving radiation and temozolomide. Additional studies are merited to evaluate the higher rate of neutropenia in patients on TMP/SMX observed in this study.

EULAR recommendations for the management of ANCA-associated vasculitis: 2022 update

BACKGROUND

Since the publication of the EULAR recommendations for the management of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) in 2016, several randomised clinical trials have been published that have the potential to change clinical care and support the need for an update.

METHODS

Using EULAR standardised operating procedures, the EULAR task force undertook a systematic literature review and sought opinion from 20 experts from 16 countries. We modified existing recommendations and created new recommendations.

RESULTS

Four overarching principles and 17 recommendations were formulated. We recommend biopsies and ANCA testing to assist in establishing a diagnosis of AAV. For remission induction in life-threatening or organ-threatening AAV, we recommend a combination of high-dose glucocorticoids (GCs) in combination with either rituximab or cyclophosphamide. We recommend tapering of the GC dose to a target of 5 mg prednisolone equivalent/day within 4-5 months. Avacopan may be considered as part of a strategy to reduce exposure to GC in granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA). Plasma exchange may be considered in patients with rapidly progressive glomerulonephritis. For remission maintenance of GPA/MPA, we recommend rituximab. In patients with relapsing or refractory eosinophilic GPA, we recommend the use of mepolizumab. Azathioprine and methotrexate are alternatives to biologics for remission maintenance in AAV.

CONCLUSIONS

In the light of recent advancements, these recommendations provide updated guidance on AAV management. As substantial data gaps still exist, informed decision-making between physicians and patients remains of key relevance.

Antibiotic prophylaxis in immunosuppressed patients - Missed opportunities from trimethoprim-sulfamethoxazole allergy label

Trimethoprim-sulfamethoxazole (TMP-SMX) is a broad spectrum antibiotic in use for more than 50 years. It has an important indication as first line agent in the prophylaxis of opportunistic infections, particularly Pneumocystis jirovecii pneumonia (PJP), in immunosuppressed patients. For those who have a history of allergy or severe intolerance to TMP-SMX, pentamidine, dapsone or atovaquone may be substituted; however there is evidence that TMP-SMX offers superior coverage for PJP, toxoplasmosis, and nocardiosis. Compared to pentamidine, it has the added benefit of cost-effectiveness and self-administration as opposed to required hospital attendance for administration. Many patients who report a history of allergy or adverse reaction to TMP-SMX (or "sulfur allergy") will be found not to be allergic; and even those who are allergic may be able to be desensitized. The evaluation and, where appropriate, removal of TMP-SMX allergy label enables the use of TMP-SMX for prophylaxis against opportunistic infections. This is a cost-effective intervention to optimize antimicrobial prescribing and reduce the risk of opportunistic infections in immunosuppressed patients.

Indian Guidelines on Nebulization Therapy

Inhalational therapy, today, happens to be the mainstay of treatment in obstructive airway diseases (OADs), such as asthma, chronic obstructive pulmonary disease (COPD), and is also in the present, used in a variety of other pulmonary and even non-pulmonary disorders. Hand-held inhalation devices may often be difficult to use, particularly for children, elderly, debilitated or distressed patients. Nebulization therapy emerges as a good option in these cases besides being useful in the home care, emergency room and critical care settings. With so many advancements taking place in nebulizer technology; availability of a plethora of drug formulations for its use, and the widening scope of this therapy; medical practitioners, respiratory therapists, and other health care personnel face the challenge of choosing appropriate inhalation devices and drug formulations, besides their rational application and use in different clinical situations. Adequate maintenance of nebulizer equipment including their disinfection and storage are the other relevant issues requiring guidance. Injudicious and improper use of nebulizers and their poor maintenance can sometimes lead to serious health hazards, nosocomial infections, transmission of infection, and other adverse outcomes. Thus, it is imperative to have a proper national guideline on nebulization practices to bridge the knowledge gaps amongst various health care personnel involved in this practice. It will also serve as an educational and scientific resource for healthcare professionals, as well as promote future research by identifying neglected and ignored areas in this field. Such comprehensive guidelines on this subject have not been available in the country and the only available proper international guidelines were released in 1997 which have not been updated for a noticeably long period of over two decades, though many changes and advancements have taken place in this technology in the recent past. Much of nebulization practices in the present may not be evidence-based and even some of these, the way they are currently used, may be ineffective or even harmful. Recognizing the knowledge deficit and paucity of guidelines on the usage of nebulizers in various settings such as inpatient, out-patient, emergency room, critical care, and domiciliary use in India in a wide variety of indications to standardize nebulization practices and to address many other related issues; National College of Chest Physicians (India), commissioned a National task force consisting of eminent experts in the field of Pulmonary Medicine from different backgrounds and different parts of the country to review the available evidence from the medical literature on the scientific principles and clinical practices of nebulization therapy and to formulate evidence-based guidelines on it. The guideline is based on all possible literature that could be explored with the best available evidence and incorporating expert opinions. To support the guideline with high-quality evidence, a systematic search of the electronic databases was performed to identify the relevant studies, position papers, consensus reports, and recommendations published. Rating of the level of the quality of evidence and the strength of recommendation was done using the GRADE system. Six topics were identified, each given to one group of experts comprising of advisors, chairpersons, convenor and members, and such six groups (A-F) were formed and the consensus recommendations of each group was included as a section in the guidelines (Sections I to VI). The topics included were: A. Introduction, basic principles and technical aspects of nebulization, types of equipment, their choice, use, and maintenance B. Nebulization therapy in obstructive airway diseases C. Nebulization therapy in the intensive care unit D. Use of various drugs (other than bronchodilators and inhaled corticosteroids) by nebulized route and miscellaneous uses of nebulization therapy E. Domiciliary/Home/Maintenance nebulization therapy; public & health care workers education, and F. Nebulization therapy in COVID-19 pandemic and in patients of other contagious viral respiratory infections (included later considering the crisis created due to COVID-19 pandemic). Various issues in different sections have been discussed in the form of questions, followed by point-wise evidence statements based on the existing knowledge, and recommendations have been formulated.

Evolving epidemiology of pneumocystis pneumonia: Findings from a longitudinal population-based study and a retrospective multi-center study in Germany

Background

Pneumocystis pneumonia (PCP) is a life-threatening opportunistic infectious disease of immunocompromised patients. Its incidence has decreased worldwide in the past, but data concerning its recent epidemiology are lacking.

Methods

We retrospectively analyzed all German inpatient cases from January 1, 2014 to December 31, 2019, to describe the recent epidemiology, incidence, clinical course, mortality and underlying diseases of PCP. Simultaneously, we conducted a retrospective multi-center study at two German university hospitals, and analyzed PCP cases treated there to gain deeper insights on the basis of primary patient data.

Findings

The incidence of PCP significantly increased from 2·3 to 2·6 per 100,000 population from 2014 to 2019 (1,857 to 2,172 cases, +17·0%, p < 0·0001), as well as PCP-related deaths (516 to 615 cases, +19·2%, p = 0·011). The spectrum of underlying diseases changed: Risk groups with established chemoprophylaxis for PCP based on international guidelines (HIV, hematologic malignancies, and transplantation) showed a significant decrease in PCP cases and deaths. Others, especially those with solid malignancies, and autoimmune and pulmonary diseases showed a significant increase in case numbers and deaths. Data from the retrospective multi-center study added information regarding prophylaxis and diagnostics of PCP.

Interpretation

The incidence of PCP has reversed its trend, showing a significant increase in mortality on population level. Patients who were not previously considered in prophylactic measures are increasingly affected by PCP. This development deserves further investigation, and additional comprehensive guidelines for the use of chemoprophylaxis in new risk groups are needed.

Funding

Department of Nephrology and Hypertension, University Hospital Schleswig-Holstein, Kiel.

Trends in the Epidemiology and Outcomes of Pneumocystis Pneumonia among Human Immunodeficiency Virus (HIV) Hospitalizations

Introduction: Pneumocystis Pneumonia (PCP) is a common opportunistic infection among people living with the human immunodeficiency virus (HIV). This study’s objective was to assess temporal trends in PCP epidemiology among hospitalized patients with HIV/AIDS in the US and to compare data for hospitalizations with HIV with PCP to those without PCP. Methods: The national inpatient sample (NIS) data were analyzed from 2002−2014. The discharge coding identified hospitalized patients with HIV or AIDS and with or without PCP. Results: We identified 3,011,725 hospitalizations with HIV/AIDS during the study period; PCP was present in 5% of the patients with a diagnosis of HIV. The rates of PCP progressively declined from 6.7% in 2002 to 3.5 % in 2014 (p < 0.001). Overall mortality in patients with HIV was 3.3% and was significantly higher in those with PCP than without PCP (9.9% vs. 2.9%; p < 0.001). After adjusting for demographics and other comorbidities, PCP had higher odds of hospital mortality 3.082 (OR 3.082; 95% CI, 3.007 to 3.159; p < 0.001). Conclusion: From 2002 to 2014, the rate of PCP in HIV patients has decreased significantly in the United States but is associated with substantially higher mortality.

A Fatal Case of Concurrent Disseminated Tuberculosis, Pneumocystis Pneumonia, and Bacterial Septic Shock in a Patient with Rheumatoid Arthritis Receiving Methotrexate, Glucocorticoid, and Tocilizumab: An Autopsy Report

Recently, treatment for rheumatoid arthritis has dramatically improved but increases the risk of bacterial and opportunistic infections. Herein, we report a fatal case of concurrent disseminated tuberculosis, pneumocystis pneumonia, and septic shock due to pyelonephritis caused by extended-spectrum β-lactamase-producing Escherichia coli in a patient with rheumatoid arthritis who received methotrexate, glucocorticoid, and tocilizumab. Despite undergoing intensive treatment, the patient developed respiratory failure and died after 7 days of admission. An autopsy indicated that pulmonary tuberculosis were the ultimate causes of death, while pyelonephritis was controlled.

MgrB Inactivation Confers Trimethoprim Resistance in Escherichia coli

After several decades of use, trimethoprim (TMP) remains one of the key access antimicrobial drugs listed by the World Health Organization. To circumvent the problem of trimethoprim resistance worldwide, a better understanding of drug-resistance mechanisms is required. In this study, we screened the single-gene knockout library of Escherichia coli, and identified mgrB and other several genes involved in trimethoprim resistance. Subsequent comparative transcriptional analysis between ΔmgrB and the wild-type strain showed that expression levels of phoP, phoQ, and folA were significantly upregulated in ΔmgrB. Further deleting phoP or phoQ could partially restore trimethoprim sensitivity to ΔmgrB, and co-overexpression of phoP/Q caused TMP resistance, suggesting the involvement of PhoP/Q in trimethoprim resistance. Correspondingly, MgrB and PhoP were shown to be able to modulated folA expression in vivo. After that, efforts were made to test if PhoP could directly modulate the expression of folA. Though phosphorylated PhoP could bind to the promotor region of folA in vitro, the former only provided a weak protection on the latter as shown by the DNA footprinting assay. In addition, deleting the deduced PhoP box in ΔmgrB could only slightly reverse the TMP resistance phenotype, suggesting that it is less likely for PhoP to directly modulate the transcription of folA. Taken together, our data suggested that, in E. coli, MgrB affects susceptibility to trimethoprim by modulating the expression of folA with the involvement of PhoP/Q. This work broadens our understanding of the regulation of folate metabolism and the mechanisms of TMP resistance in bacteria.

Risk factors associated with increased discontinuation rate of trimethoprim-sulfamethoxazole used as a primary prophylaxis for Pneumocystis pneumonia: A retrospective cohort study

BACKGROUND

The use of trimethoprim-sulfamethoxazole (TMP-SMX) for Pneumocystis pneumonia (PcP) prophylaxis is often discontinued owing to adverse drug reactions. Half-dosage of TMP-SMX (40/200 mg daily) is considered more tolerable than the conventional dosage (80/400 mg daily). However, patient background characteristics that are associated with the discontinuation of TMP-SMX prophylaxis and suitable for reduced dosage remain unclear. In this study, we aimed to identify the risk factors for the discontinuation of and efficacy of different doses of TMP-SMX prophylaxis in patients with creatinine clearance higher than 30 mL/min.

METHODS

We retrospectively evaluated 318 immunocompromised non-human immunodeficiency virus (HIV)-infected patients (194 men and 124 women; median age, 68.5 [interquartile range, 59-75] years) who underwent TMP-SMX therapy as a primary PcP prophylaxis between July 2014 and August 2019. The patients were segregated into two groups on the basis of dosage: single-strength (SS; n = 244) and half-strength (HS; n = 74) groups. We evaluated PcP occurrence, TMP-SMX discontinuation rate, and discontinuation-related risk factors in these groups.

RESULTS

PcP did not occur in either group. The univariate and multivariate Cox proportional hazards models revealed that the SS dosage and renal function (e.g. serum creatinine and creatinine clearance) were independently associated with prophylaxis discontinuation. At 24 weeks, the HS group presented significantly lower discontinuation rates than the SS group (P = 0.019, log-rank test). In the SS group, patients with mild renal impairment (e.g. serum creatinine ≥0.78 mg/dL or creatinine clearance ≤64.26 mL/min) presented significantly higher TMP-SMX discontinuation rates than those without such an impairment (P < 0.05, log-rank test with Bonferroni correction). This difference was not significant in the HS group.

CONCLUSION

Mild renal impairment might increase the risk of discontinuation of conventional TMP-SMX prophylaxis. In patients with a mild renal impairment, the HS dosage may improve tolerability while maintaining prophylactic efficacy.

Impact of prophylaxis choice on risk of pneumocystis pneumonia in children with cancer: A case-control study

BACKGROUND

Pneumocystis jirovecii pneumonia (PJP) is a life-threatening opportunistic infection. Prophylaxis is recommended for patients with malignancies and trimethoprim-sulfamethoxazole (TMP-SMX) is the recommended first-line agent. Many paediatric patients receive second-line agents due to perceived adverse reactions from TMP-SMX.

OBJECTIVE

The objective of the study is to determine the risk of PJP in patients receiving TMP-SMX vs. second-line medications for prophylaxis.

METHODS

We conducted a retrospective, single centre, case-control study of paediatric oncology patients. Cases included children diagnosed with PJP by microscopy between 2000 and 2018 while being treated for a malignancy. Controls were matched by age, oncologic diagnosis, treatment protocol, phase of treatment and oncologic diagnosis date. For each case, up to 5 controls were randomly selected. The index date was the date of the PJP diagnosis for cases and the equivalent dummy date for controls.

RESULTS

Eleven cases with PJP were identified and matched with 50 controls. Six (55%) cases and 42 (84%) controls were on prophylaxis with TMP-SMX. The remaining patients received inhaled pentamidine (3 cases, 4 controls), dapsone (2 cases, 3 controls), or atovaquone (1 control). Myelosuppression was the most common reason to stop TMP-SMX. Cases with PJP were less likely to have been taking TMP-SMX in the 3 months before diagnosis when compared with controls (odds ratio: 0.15, 95% confidence interval: 0.01-0.97, p = 0.02).

CONCLUSION

TMP-SMX prophylaxis was associated with a lower risk of developing PJP compared with second-line treatments. Although alternate agents may be required in certain situations, efforts should be made to rechallenge with TMP-SMX when possible.

High incidence of Pneumocystis jirovecii pneumonia in allogeneic hematopoietic cell transplant recipients in the modern era

BACKGROUND

International guidelines for Pneumocystis jirovecii pneumonia (PJP) prevention recommend prophylaxis for ≥6 months following allogeneic hematopoietic cell transplantation, and longer in patients with graft-versus-host disease (GVHD) or on immunosuppressive therapy (IST). These recommendations are based on cohorts of patients who did not routinely receive anti-thymocyte globulin (ATG) for GVHD prophylaxis.

METHODS

We performed a retrospective chart review of 649 patients, all of whom received ATG as part of GVHD prophylaxis.

RESULTS

The cumulative incidence of definite PJP was 3.52% at both 3 and 5 years (median follow up, 1648 days for survivors). PJP occurred in 13 non-GVHD patients between days 207 and 508, due in part to low CD4 T-cell counts (<200 CD4 T cells/µL). PJP occurred in eight GVHD patients between days 389 and 792, due in part to non-adherence to PJP prophylaxis guidelines (discontinuation of PJP prophylaxis at <3 months after discontinuation of IST). Breakthrough PJP infection was not observed in patients receiving prophylaxis with cotrimoxazole, dapsone or atovaquone, whereas three cases were observed with inhaled pentamidine.

DISCUSSION

In conclusion, for non-GVHD patients receiving ATG-containing GVHD prophylaxis, 6 months of PJP prophylaxis is inadequate, particularly if the CD4 T-cell count is <200 cells/µL or if there is a high incidence of PJP in the community. For patients with GVHD receiving ATG-containing GVHD prophylaxis, continuing PJP prophylaxis until ≥3 months post-discontinuation of IST is important. Cotrimoxazole, dapsone and atovaquone are preferred over inhaled pentamidine.

Spore Germination as a Target for Antifungal Therapeutics

Spores are required for long-term survival of many organisms, including most fungi. For the majority of fatal human fungal pathogens, spore germination is the key process required to initiate vegetative growth and ultimately cause disease. Because germination is required for pathogenesis, the process could hold fungal-specific targets for new antifungal drug development. Compounds that inhibit germination could be developed into high efficacy, low-toxicity drugs for use in the prevention and/or treatment of fungal spore-mediated diseases. To identify drugs with the ability to inhibit pathogenic fungal spore germination, we developed a novel luciferase-based germination assay, using spores of the meningitis-causing yeast Cryptococcus. We screened the L1300 Selleck Library of FDA-approved drugs and identified 27 that inhibit germination. Of these, 22 inhibited both germination and yeast growth, and 21 have not been previously indicated for use in the treatment of fungal diseases. We quantitated the inhibition phenotypes of 10 specific germination/growth inhibitors in detail and tested one drug, the antiparasitic compound pentamidine, in our mouse intranasal model of cryptococcal infection. We discovered that pentamidine was effective at reducing lung fungal burdens when used in either prophylaxis (before infection) or treatment (after establishing an infection). Due to its efficacy in vivo and low intranasal toxicity, pentamidine is a lead candidate for repurposing for broader use as an antigerminant to prevent spore-mediated disease in immunocompromised patients. Not only does pentamidine provide an opportunity for prophylaxis against fungal spores, but it also provides proof of concept for targeting pathogenic spore germination for antifungal drug development.

Management of Advanced HIV Disease

Great progress has been made in caring for persons with human immunodeficiency virus. However, a significant proportion of individuals still present to care with advanced disease and a low CD4 count. Careful considerations for selection of antiretroviral therapy as well as close monitoring for opportunistic infections and immune reconstitution inflammatory syndrome are vitally important in providing care for such individuals.

Pneumocystis pneumonia in HIV-1-infected patients

Pneumocystis pneumonia (PCP) is an opportunistic disease that mainly affects patients with a deficiency of cell-mediated immunity, especially acquired immunodeficiency syndrome (AIDS). The incidence of PCP in these patients has declined substantially owing to the widespread use of antiretroviral therapy and PCP prophylaxis. However, PCP is still a major AIDS-related opportunistic infection, particularly in patients with advanced immunosuppression in whom human immunodeficiency virus type 1 (HIV-1) infection remains undiagnosed or untreated. The clinical manifestations, diagnosis, treatment, and prevention of PCP in patients with HIV-1 infection are addressed in this review.

Efficacies of atovaquone, pentamidine, and trimethoprim/sulfamethoxazole for the prevention of Pneumocystis jirovecii pneumonia in patients with connective tissue diseases

BACKGROUND

Pneumocystis jirovecii pneumonia (PCP) is an opportunistic infection in patients on steroid therapy for connective tissue diseases. The standard agent for primary PCP prophylaxis is trimethoprim/sulfamethoxazole (TMP-SMX), although this agent can cause common adverse reactions, including myelosuppression and renal toxicity, that result in cessation. Aerosolized pentamidine and oral atovaquone are alternatives for PCP prophylaxis. The efficacies of atovaquone, pentamidine, and TMP-SMX to prevent PCP in patients with connective tissue diseases have never been compared.

METHODS

Hospitalized patients with connective tissue diseases who started steroid therapy and PCP prophylaxis were enrolled. PCP prophylaxis regimens were oral TMP-SMX, aerosolized pentamidine, or oral atovaquone. Information was retrospectively collected from medical records about laboratory findings, duration of PCP prophylaxis, and reasons for terminating PCP prophylaxis.

RESULTS

Ninety-six patients received PCP prophylaxis. All of them were initially treated with TMP-SMX, but this was replaced during the study period with pentamidine in 33 patients and with atovaquone in 7. Forty-one (43%) patients discontinued TMP-SMX because of adverse events, and 5 (15%) also discontinued pentamidine. None of the patients discontinued atovaquone. The most frequent causes of TMP-SMX and pentamidine cessation were cytopenia (N = 15) and asthma (N = 2). The rates of continuing treatment with TMP-SMX, pentamidine, and atovaquone at one year after starting PCP prophylaxis were 55.3%, 68.6%, and 100%, respectively (P = 0.01). None of the patients developed PCP.

CONCLUSION

Although TMP-SMX for PCP prophylaxis had to be discontinued in 43% of patients with connective tissue diseases, pentamidine and atovaquone were well tolerated.

Therapy and Management of Pneumocystis jirovecii Infection

The rates of Pneumocystis pneumonia (PcP) are increasing in the HIV-negative susceptible population. Guidance for the prophylaxis and treatment of PcP in HIV, haematology, and solid-organ transplant (SOT) recipients is available, although for many other populations (e.g., auto-immune disorders) there remains an urgent need for recommendations. The main drug for both prophylaxis and treatment of PcP is trimethoprim/sulfamethoxazole, but resistance to this therapy is emerging, placing further emphasis on the need to make a mycological diagnosis using molecular based methods. Outbreaks in SOT recipients, particularly renal transplants, are increasingly described, and likely caused by human-to-human spread, highlighting the need for efficient infection control policies and sensitive diagnostic assays. Widespread prophylaxis is the best measure to gain control of outbreak situations. This review will summarize diagnostic options, cover prophylactic and therapeutic management in the main at risk populations, while also covering aspects of managing resistant disease, outbreak situations, and paediatric PcP.

Prophylaxis of human toxoplasmosis: a systematic review

Toxoplasmosis is an infection caused by the intracellular protozoan parasite Toxoplasma gondii, and is associated with clinically significant infection in immunocompromised individuals. Vertical transmission during pregnancy can manifest as congenital toxoplasmosis in the neonate, and can have serious consequences. This review aims to describe the modalities for prophylaxis of toxoplasmosis in susceptible populations, and focuses on the following: (1) prophylaxis of congenital toxoplasmosis; (2) prophylaxis of toxoplasmosis in patients with HIV/AIDS; and (3) prophylaxis of toxoplasmosis in transplant recipients.

Treatment of Pneumocystis jirovecii pneumonia in HIV-infected patients: a review

INTRODUCTION

Pneumocystis pneumonia is a potentially life-threatening pulmonary infection that occurs in immunocompromised individuals and HIV-infected patients with a low CD4 cell count. Trimethoprim-sulfamethoxazole has been used as the first-line agent for treatment, but mutations within dihydropteroate synthase gene render potential resistance to sulfamide. Despite advances of combination antiretroviral therapy (cART), Pneumocystis pneumonia continues to occur in HIV-infected patients with late presentation for cART or virological and immunological failure after receiving cART. Areas covered: This review summarizes the diagnosis and first-line and alternative treatment and prophylaxis for Pneumocystis pneumonia in HIV-infected patients. Articles for this review were identified through searching PubMed. Search terms included: 'Pneumocystis pneumonia', 'Pneumocystis jirovecii pneumonia', 'Pneumocystis carinii pneumonia', 'trimethoprim-sulfamethoxazole', 'primaquine', 'trimetrexate', 'dapsone', 'pentamidine', 'atovaquone', 'echinocandins', 'human immunodeficiency virus infection', 'acquired immunodeficiency syndrome', 'resistance to sulfamide' and combinations of these terms. We limited the search to English language papers that were published between 1981 and March 2017. We screened all identified articles and cross-referenced studies from retrieved articles. Expert commentary: Trimethoprim-sulfamethoxazole will continue to be the first-line agent for Pneumocystis pneumonia given its cost, availability of both oral and parenteral formulations, and effectiveness or efficacy in both treatment and prophylaxis. Whether resistance due to mutations within dihydropteroate synthase gene compromises treatment effectiveness remains controversial. Continued search for effective alternatives with better safety profiles for Pneumocystis pneumonia is warranted.

Deletion of nudB Causes Increased Susceptibility to Antifolates in Escherichia coli and Salmonella enterica

Co-trimoxazole, a fixed-dose combination of sulfamethoxazole (SMX) and trimethoprim (TMP), has been used for the treatment of bacterial infections since the 1960s. Since it has long been assumed that the synergistic effects between SMX and TMP are the consequence of targeting 2 different enzymes of bacterial folate biosynthesis, 2 genes (pabB and nudB) involved in the folate biosynthesis of Escherichia coli were deleted, and their effects on the susceptibility to antifolates were tested. The results showed that the deletion of nudB resulted in a lag of growth in minimal medium and increased susceptibility to both SMX and TMP. Moreover, deletion of nudB also greatly enhanced the bactericidal effect of TMP. To elucidate the mechanism of how the deletion of nudB affects the bacterial growth and susceptibility to antifolates, 7,8-dihydroneopterin and 7,8-dihydropteroate were supplemented into the growth medium. Although those metabolites could restore bacterial growth, they had no effect on susceptibilities to the antifolates. Reverse mutants of the nudB deletion strain were isolated to further study the mechanism of how the deletion of nudB affects susceptibility to antifolates. Targeted sequencing and subsequent genetic studies revealed that the disruption of the tetrahydromonapterin biosynthesis pathway could reverse the phenotype caused by the nudB deletion. Meanwhile, overexpression of folM could also lead to increased susceptibility to both SMX and TMP. These data suggested that the deletion of nudB resulted in the excess production of tetrahydromonapterin, which then caused the increased susceptibility to antifolates. In addition, we found that the deletion of nudB also resulted in increased susceptibility to both SMX and TMP in Salmonella enterica Since dihydroneopterin triphosphate hydrolase is an important component of bacterial folate biosynthesis and the tetrahydromonapterin biosynthesis pathway also exists in a variety of bacteria, it will be interesting to design new compounds targeting dihydroneopterin triphosphate hydrolase, which may inhibit bacterial growth and simultaneously potentiate the antimicrobial activities of antifolates targeting other components of folate biosynthesis.

Diagnosis and management of Pneumocystis jirovecii infection

INTRODUCTION

Pneumocystis jirovecii is a ubiquitous fungus, which causes pneumonia in humans. Diagnosis was hampered by the inability to culture the organism, and based on microscopic examination of respiratory samples or clinical presentation. New assays can assist in the diagnosis and even aid with the emergence of resistant infections. Areas covered: This manuscript will provide background information on Pneumocystis pneumonia (PcP). Diagnosis, from radiological to non-microbiological (e.g. Lactate dehydrogenase) and microbiological investigations (Microscopy, PCR, β-D-Glucan) will be discussed. Recommendations on prophylactic and therapeutic management will be covered. Expert commentary: PcP diagnosis using microscopy is far from optimal and false negatives will occur. With an incidence of 1% or less, the pre-test probability of not having PcP is 99% and testing is suited to excluding disease. Microscopy provides a high degree of diagnostic confidence but it is not infallible, and its lower sensitivity limits its application. Newer diagnostics (PCR, β-D-Glucan) can aid management and improve performance when testing less invasive specimens, such as upper respiratory samples or blood, alleviating clinical pressure. Combination testing may allow PcP to be both diagnosed and excluded, and molecular testing can assist in the detection of emerging resistant PcP.

Pneumocystis jirovecii Pneumonia in Rheumatoid Arthritis Patients: Risks and Prophylaxis Recommendations

Pneumocystis jirovecii infection causes fulminant interstitial pneumonia (Pneumocystis pneumonia, PCP) in patients with rheumatoid arthritis (RA) who are receiving biological and/or nonbiological antirheumatic drugs. Recently, we encountered a PCP outbreak among RA outpatients at our institution. Hospital-acquired, person-to-person transmission appears to be the most likely mode of this cluster of P. jirovecii infection. Carriage of P. jirovecii seems a time-limited phenomenon in immunocompetent hosts, but in RA patients receiving antirheumatic therapy, clearance of this organism from the lungs is delayed. Carriers among RA patients can serve as sources and reservoirs of P. jirovecii infection for other susceptible patients in outpatient facilities. Development of PCP is a matter of time in such carriers. Considering the poor survival rates of PCP cases, prophylactic antibiotics should be considered for RA patients who are scheduled to receive antirheumatic therapy. Once a new case of PCP occurs, we should take prompt action not only to treat the PCP patient but also to prevent other patients from becoming new carriers of P. jirovecii. Short-term prophylaxis with trimethoprim-sulfamethoxazole is effective in controlling P. jirovecii infection and preventing future outbreaks of PCP among RA patients.

Fatal Pneumocystis jirovecii pneumonia in a HIV-negative adult

Pneumocystis jirovecii is responsible for P. jirovecii pneumonia (PJP) in immunocompromised individuals, with a recent rise of cases noted in non-HIV patients. A middle-aged man presented with new-onset cough, fever, hypoxia and tachypnoea. He was on a tapering course of dexamethasone for amiodarone-induced thyrotoxicosis. He developed worsening airspace disease necessitating mechanical ventilation. Bronchoalveolar lavage (BAL) fluid was positive for P. jirovecii and he was managed with trimethoprim/sulfamethoxazole and pentamidine, but succumbed to cardiorespiratory arrest. One-third of PJP cases occur in non-HIV patients, and have a higher morbidity and mortality. Most immunocompromised patients typically exhibit PJP during a corticosteroid taper. The accurate dose, duration or frequency of steroid use in not well established. Diagnosis of PJP in this population is more challenging due to lower BAL yield with alternate modalities such as serum/BAL β-d-glucan and PCR enhancing the yield. Further studies are needed to highlight PJP prophylaxis in patients with steroid use.

Pneumocystis Pneumonia in Human Immunodeficiency Virus-infected Adults and Adolescents: Current Concepts and Future Directions

Pneumocystis jirovecii pneumonia (PCP) is one of the most common opportunistic infections in human immunodeficiency virus–infected adults. Colonization of Pneumocystis is highly prevalent among the general population and could be associated with the transmission and development of PCP in immunocompromised individuals. Although the microscopic demonstration of the organisms in respiratory specimens is still the golden standard of its diagnosis, polymerase chain reaction has been shown to have a high sensitivity, detecting Pneumocystis DNA in induced sputum or oropharyngeal wash. Serum β-D-glucan is useful as an adjunctive tool for the diagnosis of PCP. High-resolution computed tomography, which typically shows diffuse ground-glass opacities, is informative for the evaluation of immunocompromised patients with suspected PCP and normal chest radiography. Trimethoprim–sulfamethoxazole (TMP-SMX) is the first-line agent for the treatment of mild to severe PCP, although it is often complicated with various side effects. Since TMP-SMX is widely used for the prophylaxis, the putative drug resistance is an emerging concern.

Inhaled anti-infective chemotherapy for respiratory tract infections: successes, challenges and the road ahead

One of the most common causes of illnesses in humans is from respiratory tract infections caused by bacterial, viral or fungal pathogens. Inhaled anti-infective drugs are crucial for the prophylaxis and treatment of respiratory tract infections. The benefit of anti-infective drug delivery via inhalation is that it affords delivery of sufficient therapeutic dosages directly to the primary site of infection, while minimizing the risks of systemic toxicity or avoiding potential suboptimal pharmacokinetics/pharmacodynamics associated with systemic drug exposure. This review provides an up-to-date treatise of approved and novel developmental inhaled anti-infective agents, with particular attention to effective strategies for their use, pulmonary pharmacokinetic properties and safety.

Diagnosis and antimicrobial therapy of lung infiltrates in febrile neutropenic patients (allogeneic SCT excluded): updated guidelines of the Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Medical Oncology (DGHO)

Up to 25% of patients with profound neutropenia lasting for >10 days develop lung infiltrates, which frequently do not respond to broad-spectrum antibacterial therapy. While a causative pathogen remains undetected in the majority of cases, Aspergillus spp., Pneumocystis jirovecii, multi-resistant Gram-negative pathogens, mycobacteria or respiratory viruses may be involved. In at-risk patients who have received trimethoprim-sulfamethoxazole (TMP/SMX) prophylaxis, filamentous fungal pathogens appear to be predominant, yet commonly not proven at the time of treatment initiation. Pathogens isolated from blood cultures, bronchoalveolar lavage (BAL) or respiratory secretions are not always relevant for the etiology of pulmonary infiltrates and should therefore be interpreted critically. Laboratory tests for detecting Aspergillus galactomannan, β-D-glucan or DNA from blood, BAL or tissue samples may facilitate the diagnosis; however, most polymerase chain reaction assays are not yet standardized and validated. Apart from infectious agents, pulmonary side-effects from cytotoxic drugs, radiotherapy or pulmonary involvement by the underlying malignancy should be included into differential diagnosis and eventually be clarified by invasive diagnostic procedures. Pre-emptive treatment with mold-active systemic antifungal agents improves clinical outcome, while other microorganisms are preferably treated only when microbiologically documented. High-dose TMP/SMX is first choice for treatment of Pneumocystis pneumonia, while cytomegalovirus pneumonia is treated primarily with ganciclovir or foscarnet in most patients. In a considerable number of patients, clinical outcome may be favorable despite respiratory failure, so that intensive care should be unrestrictedly provided in patients whose prognosis is not desperate due to other reasons.

Lethal Pneumocystis jiroveci pneumonia 24 Years After Kidney Transplantation

INTRODUCTION

Pneumocystis jiroveci is an opportunistic infectious fungus in immunosuppressed patients, particularly in ones with acquired immunodeficiency syndrome (AIDS). The use of immunosuppressive drugs especially corticosteroids predisposes the transplanted patients to a variety of infectious diseases including Pneumocystis infection. In many developed countries, the incidence of Pneumocystis jiroveci pneumonia (PJP) is dwindling in transplant patients receiving appropriate prophylaxis. In this study, definitive diagnosis of Pneumocystis infection in a patient receiving kidney transplant was presented.

CASE PRESENTATION

The patient was a 45-year-old man with a history of kidney transplantation 24 years ago, admitted to a specialized hospital in Tehran because of fever and respiratory distress. Upon admission, the patient showed symptoms of unconsciousness and shortness of breath. Paraclinical tests and complementary examinations such as microscopic observation and molecular analysis confirmed the definitive diagnosis of Pneumocystis infection. Specific treatment with trimethoprim/sulfamethoxazole was carried out alongside other therapeutic measures; but unfortunately the patient did not respond to the specific treatment and died in the course of a progressive disease.

DISCUSSION

The disease progress in these patients can still be fast and deadly. Applying rapid molecular diagnostic techniques to start appropriate and timely treatment is essential. Utilization of such diagnostic methods is recommended in our country.

Positivity for anti-RNP antibody is a risk factor for adverse effects caused by trimethoprim-sulfamethoxazole, a prophylactic agent for P. jiroveci pneumonia, in patients with connective tissue diseases

OBJECTIVES

Trimethoprim-sulphamethoxazole (TMP-STX), an agent used for prophylaxis against pneumocystis pneumonia (PCP) in immunocompromised hosts, causes serious adverse effects (AEs) in some patients. The objective of this study was to identify the risk factors for AEs caused by TMP-STX in connective tissue disease (CTD) patients and to describe the clinical features of the AEs.

METHODS

The medical records of 539 patients (CTDs 312, pulmonary diseases 227) receiving TMP-STX for prophylaxis against PCP were reviewed retrospectively. Patients with human immunodeficiency virus were excluded. Univariate and multivariate analyses were conducted to identify the risk factors.

RESULTS

Adverse events caused by TMP-STX occurred in 22 of 312 (7.05 %) CTD patients, while only six of 227 (2.64 %) pulmonary disease patients developed AEs. The incidence of AEs was significantly higher in systemic lupus erythematosus (SLE) (11.0 %) and mixed connective tissue disease (MCTD) (33.3 %) patients than in other CTD patients. AEs occurred in 25 % of patients with anti-RNP antibody. Univariate analysis revealed that SLE, MCTD, and anti-RNP antibody were risk factors for AEs in CTD patients. Further multivariate analyses demonstrated that only anti-RNP antibody positivity was a risk factor for AEs. Systemic inflammation, including fever, was a characteristic manifestation of the AEs in CTD patients, particularly those with anti-RNP antibody.

CONCLUSIONS

Positivity for anti-RNP antibody is a risk factor for AEs caused by TMP-STX in CTD patients. Systemic inflammation, including fever, might be a characteristic feature of the AEs in CTD patients, particularly those with anti-RNP antibody.

Discontinuation of Pneumocystis jirovecii pneumonia prophylaxis with CD4 count <200 cells/µL and virologic suppression: a systematic review

BACKGROUND

HIV viral load (VL) is currently not part of the criteria for Pneumocystis jirovecii pneumonia (PCP) prophylaxis discontinuation, but suppression of plasma viremia with antiretroviral therapy may allow for discontinuation of PCP prophylaxis even with CD4 count <200 cells/µL.

METHODS

A systematic review was performed to determine the incidence of PCP in HIV-infected individuals with CD4 count <200 cells/µL and fully suppressed VL on antiretroviral therapy but not receiving PCP prophylaxis.

RESULTS

Four articles examined individuals who discontinued PCP prophylaxis with CD4 count <200 cells/µL in the context of fully suppressed VL on antiretroviral therapy. The overall incidence of PCP was 0.48 cases per 100 person-years (PY) (95% confidence interval (CI) (0.06-0.89). This was lower than the incidence of PCP in untreated HIV infection (5.30 cases/100 PY, 95% CI 4.1-6.8) and lower than the incidence in persons with CD4 count <200 cells/µL, before the availability of highly active antiretroviral therapy (HAART), who continued prophylaxis (4.85/100 PY, 95% CI 0.92-8.78). In one study in which individuals were stratified according to CD4 count <200 cells/µL, there was a greater risk of PCP with CD4 count ≤100 cells/µL compared to 101-200 cells/µL.

CONCLUSION

Primary PCP prophylaxis may be safely discontinued in HIV-infected individuals with CD4 count between 101-200 cells/µL provided the VL is fully suppressed on antiretroviral therapy. However, there are inadequate data available to make this recommendation when the CD4 count is ≤100 cells/µL. A revision of guidelines on primary PCP prophylaxis to include consideration of the VL is merited.

Fatal bilateral pneumothoraces following administration of aerosolised pentamidine

Aerosolised pentamidine (AP) is used for prophylaxis against infection with Pneumocystis jiroveci (carinii), a significant cause of morbidity and mortality for people with human immunodeficiency virus (HIV). In this article we report a 55 year old man with HIV and a background history of asthma since childhood, who suffered respiratory arrest and died within an hour of commencing AP prophylaxis. Autopsy revealed bilateral pneumothoraces. Common side effects of AP therapy include bronchospasm and coughing. Pneumothorax has been reported in several cases. To our knowledge, this is the first reported fatality from bilateral pneumothoraces.

Pneumocystis jirovecii Pneumonia

Pneumocystis jirovecii has gained attention during the last decade in the context of the AIDS epidemic and the increasing use of cytotoxic and immunosuppressive therapies. This article summarizes current knowledge on biology, pathophysiology, epidemiology, diagnosis, prevention, and treatment of pulmonary P jirovecii infection, with a particular focus on the evolving pathophysiology and epidemiology. Pneumocystis pneumonia still remains a severe opportunistic infection, associated with a high mortality rate.

Management of Pneumocystis Jirovecii pneumonia in HIV infected patients: current options, challenges and future directions

The discovery of the Human Immunodeficiency Virus (HIV) was led by the merge of clustered cases of Pneumocystis jirovecii Pneumonia (PCP) in otherwise healthy people in the early 80’s.1,2 In the face of sophisticated treatment now available for HIV infection, life expectancy approaches normal limits. It has dramatically changed the natural course of HIV from a nearly fatal infection to a chronic disease.3–5 However, PCP still remains a relatively common presentation of uncontrolled HIV. Despite the knowledge and advances gained in the prevention and management of PCP infection, it continues to have high morbidity and mortality rates. Trimethoprim-sulfamethoxazole (TMP-SMZ) remains as the recommended first-line treatment. Alternatives include pentamidine, dapsone plus trimethoprim, clindamycin administered with primaquine, and atovaquone. For optimal management, clinicians need to be familiar with the advantages and disadvantages of the available drugs. The parameters used to classify severity of infection are also important, as it is well known that the adjunctive use of steroids in moderate to severe cases have been shown to significantly improve outcome. Evolving management practices, such as the successful institution of early antiretroviral therapy, may further enhance overall survival rates.

Intermittent oral trimethoprim/sulfamethoxazole on two non-consecutive days per week is effective as Pneumocystis jiroveci pneumonia prophylaxis in pediatric patients receiving chemotherapy or hematopoietic stem cell transplantation

Pneumocystis jiroveci pneumonia (PCP) is a serious complication in patients receiving chemotherapy or hematopoietic stem cell transplantation. Current recommendations for trimethoprim-sulfamethoxazole (TMP-SMZ) dosing as PCP prophylaxis in immunocompromised patients are based on either daily dosing or dosing three consecutive days per week. We report our experience of prophylaxis with TMP-SMZ twice daily on two non-consecutive days per week in 145 immunocompromised children with hematologic disorders, cancer, or metabolic disorders following chemotherapy or hematopoietic stem cell transplantation. There were no breakthrough cases of PCP. We therefore conclude our prophylaxis regimen is effective against PCP in immunocompromised children.

Using the zebrafish lateral line to screen for ototoxicity

The zebrafish is a valuable model for studying hair cell development, structure, genetics, and behavior. Zebrafish and other aquatic vertebrates have hair cells on their body surface organized into a sensory system called the lateral line. These hair cells are highly accessible and easily visualized using fluorescent dyes. Morphological and functional similarities to mammalian hair cells of the inner ear make the zebrafish a powerful preparation for studying hair cell toxicity. The ototoxic potential of drugs has historically been uncovered by anecdotal reports that have led to more formal investigation. Currently, no standard screen for ototoxicity exists in drug development. Thus, for the vast majority of Food and Drug Association (FDA)-approved drugs, the ototoxic potential remains unknown. In this study, we used 5-day-old zebrafish larvae to screen a library of 1,040 FDA-approved drugs and bioactives (NINDS Custom Collection II) for ototoxic effects in hair cells of the lateral line. Hair cell nuclei were selectively labeled using a fluorescent vital dye. For the initial screen, fish were exposed to drugs from the library at a 100-muM concentration for 1 h in 96-well tissue culture plates. Hair cell viability was assessed in vivo using fluorescence microscopy. One thousand forty drugs were rapidly screened for ototoxic effects. Seven known ototoxic drugs included in the library, including neomycin and cisplatin, were positively identified using these methods, as proof of concept. Fourteen compounds without previously known ototoxicity were discovered to be selectively toxic to hair cells. Dose-response curves for all 21 ototoxic compounds were determined by quantifying hair cell survival as a function of drug concentration. Dose-response relationships in the mammalian inner ear for two of the compounds without known ototoxicity, pentamidine isethionate and propantheline bromide, were then examined using in vitro preparations of the adult mouse utricle. Significant dose-dependent hair cell loss in the mouse utricle was demonstrated for both compounds. This study represents an important step in validating the use of the zebrafish lateral line as a screening tool for the identification of potentially ototoxic drugs.

Management of Pneumocystis jiroveci pneumonia in children receiving chemotherapy

Pneumocystis jiroveci (formerly carinii) pneumonia (PCP) is a serious opportunistic infection in children and adolescents with cancer. It was the most common cause of death among children receiving chemotherapy prior to the inclusion of PCP prophylaxis as part of standard care for children with leukemia. The incidence of PCP has decreased significantly since initiation of prophylaxis; however, breakthrough cases continue to occur. Hematologic malignancies, brain tumors necessitating prolonged corticosteroid therapy, hematopoietic stem cell transplantation, prolonged neutropenia, and lymphopenia are the most important risk factors for PCP in children not infected with HIV. Of children with leukemia, 15-20% may develop PCP in the absence of prophylaxis. Infection with P. jiroveci occurs early in life in most individuals. However, clinically apparent disease occurs almost exclusively in immunocompromised persons. Dyspnea, cough, hypoxia, and fever are the most common presenting symptoms of PCP. Chest radiography and high-resolution CT scans of the chest demonstrate a characteristic ground-glass pattern. Induced sputum analysis and bronchoalveolar lavage are the diagnostic procedures of choice. Gomori's methenamine-silver stain, Geimsa or Wright's stain, and monoclonal immunofluorescent antibody stains are most commonly used to make a diagnosis. However, identification of P. jiroveci DNA using polymerase chain reaction assays in bronchoalveolar lavage fluid is more sensitive. Trimethoprim-sulfamethoxazole (TMP-SMZ; cotrimoxazole) is the recommended drug for the treatment of PCP. Patients who are intolerant of TMP-SMZ or who have not responded to treatment after 5-7 days of therapy with TMP-SMZ should be treated with pentamidine. A short course of corticosteroids is recommended for moderate to severe cases of PCP within the first 72 hours after diagnosis. Mutations in the dihydropteroate synthetase gene may confer resistance to TMP-SMZ; however, the clinical relevance of these mutations is not well established. TMP-SMZ is the most commonly used agent for prophylaxis. Myelosuppression is the most important adverse effect of TMP-SMZ and the most frequent cause for choosing alternative prophylactic agents in children undergoing chemotherapy. Alternative agents for chemoprophylaxis include dapsone, aerosolized pentamidine, and atovaquone. Alternative prophylactic agents must be used in patients developing myelosuppression secondary to TMP-SMZ or dapsone.