Considerations when prescribing trimethoprim-sulfamethoxazole

Treatment of toxoplasmic encephalitis with the combination of clindamycin plus azithromycin in an HIV-infected patient: A case report

The existence of alternative oral therapies could help clinicians to treat toxoplasmic encephalitis (TE) in the HIV patients. The combination of azithromycin and clindamycin may serve as an effective treatment for TE in HIV-infected patients.

Characterization of T-Cell Responses to SMX and SMX-NO in Co-Trimoxazole Hypersensitivity Patients Expressing HLA-B*13:01

HLA-B*13:01-positive patients in Thailand can develop frequent co-trimoxazole hypersensitivity reactions. This study aimed to characterize drug-specific T cells from three co-trimoxazole hypersensitive patients presenting with either Stevens-Johnson syndrome or drug reaction with eosinophilia and systemic symptoms. Two of the patients carried the HLA allele of interest, namely HLA-B*13:01. Sulfamethoxazole and nitroso sulfamethoxazole specific T cell clones were generated from T cell lines of co-trimoxazole hypersensitive HLA-B*13:01-positive patients. Clones were characterized for antigen specificity and cross-reactivity with structurally related compounds by measuring proliferation and cytokine release. Surface marker expression was characterized via flow cytometry. Mechanistic studies were conducted to assess pathways of T cell activation in response to antigen stimulation. Peripheral blood mononuclear cells from all patients were stimulated to proliferate and secrete IFN-γ with nitroso sulfamethoxazole. All sulfamethoxazole and nitroso sulfamethoxazole specific T cell clones expressed the CD4+ phenotype and strongly secreted IL-13 as well as IFN-γ, granzyme B and IL-22. No secretion of IL-17 was observed. A number of nitroso sulfamethoxazole-specific clones cross-reacted with nitroso dapsone but not sulfamethoxazole whereas sulfamethoxazole specific clones cross-reacted with nitroso sulfamethoxazole only. The nitroso sulfamethoxazole specific clones were activated in both antigen processing-dependent and -independent manner, while sulfamethoxazole activated T cell responses via direct HLA binding. Furthermore, activation of nitroso sulfamethoxazole-specific, but not sulfamethoxazole-specific, clones was blocked with glutathione. Sulfamethoxazole and nitroso sulfamethoxazole specific T cell clones from hypersensitive patients were CD4+ which suggests that HLA-B*13:01 is not directly involved in the iatrogenic disease observed in co-trimoxazole hypersensitivity patients.

Urinary tract infection pocket card effect on preferred antimicrobial prescribing for cystitis among patients discharged from the emergency department

PURPOSE

To evaluate the impact of a urinary tract infection (UTI) pocket card on preferred antibiotic prescribing for patients discharged from the emergency department (ED) with a diagnosis of cystitis.

METHODS

A multicenter, retrospective, pre-post study was conducted to compare outcomes following the introduction of a UTI pocket card. The primary outcome was prescribing rates for institutional first-line preferred antibiotics (cephalexin and nitrofurantoin) versus other antimicrobials for cystitis. Secondary outcomes included prescriber adherence to recommended therapy in regards to discharge dose, frequency, duration, and healthcare utilization rates.

RESULTS

The study included 915 patients in total, 407 in the preintervention group and 508 in the postintervention group. The frequency of preferred antibiotic prescribing was significantly increased after the introduction of a UTI pocket card compared to prior to its introduction (81.7% vs 72.0%, P = 0.001). Significant increases in prescribing of an appropriate antibiotic dose (78.0% vs 66.8%, P < 0.0001) and frequency (64.2% vs 47.4%, P < 0.0001) were also found post intervention. No significant differences were seen between the pre- and postintervention groups with regards to healthcare utilization rates.

CONCLUSION

A UTI pocket card increased preferred antibiotic prescribing for cystitis in the ED. This study provides data on a successful antimicrobial stewardship intervention in the ED setting.

The effect of Blastocystis sp. and Dientamoeba fragilis on psychological symptom severity in a sample of clinically diverse males and females

Health outcomes associated with Blastocystis sp. and Dientamoeba fragilis are disparate and controversial, ranging from health benefits, to years of asymptomatic carriage, through to severe illness. Evidence that Blastocystis sp. and D. fragilis are commensal members of the gut microbiota is growing. Despite this, little to no research exists investigating the potential effect of these protozoa on psychological symptom expression. As such, the aim of this retrospective cross-sectional study was to be the first to investigate the effect of protozoan carriage on severity of Depressive, Neurocognitive, Stress and Anxiety, and Sleep and Fatigue symptoms, and whether this effect changes as a function of sex. The prevalence of D. fragilis was significantly higher in females compared to males, however there were no sex differences in prevalence for Blastocystis sp. (data used in the current study contained ST1, ST3, and Blastocystis ST unspecified) or co-carriage of the two. Females reported significantly more severe symptoms across all four psychological domains compared to males. There was no significant interaction between sex and Blastocystis sp. carriage on psychological symptom severity, and no significant main effect of Blastocystis sp. on symptom severity compared to those who tested negative for protozoa. When investigating the sexes separately, there was no effect of protozoan carriage on psychological symptom expression in either males or females. These findings add weight to the argument that Blastocystis sp. and D. fragilis are not necessarily pathogenic and are likely to be part of a diverse gut (which is typically associated with better health outcomes). Further research is required given that protozoan members of the gut microbiota have been largely ignored in brain-gut-microbiota axis research.

Guideline for Antibacterial Prophylaxis Administration in Pediatric Cancer and Hematopoietic Stem Cell Transplantation

Background

Bacteremia and other invasive bacterial infections are common among children with cancer receiving intensive chemotherapy and in pediatric recipients of hematopoietic stem cell transplantation (HSCT). Systemic antibacterial prophylaxis is one approach that can be used to reduce the risk of these infections. Our purpose was to develop a clinical practice guideline (CPG) for systemic antibacterial prophylaxis administration in pediatric patients with cancer and those undergoing HSCT.

Methods

An international and multidisciplinary panel was convened with representation from pediatric hematology/oncology and HSCT, pediatric infectious diseases (including antibiotic stewardship), nursing, pharmacy, a patient advocate, and a CPG methodologist. The panel used the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach to generate recommendations based on the results of a systematic review of the literature.

Results

The systematic review identified 114 eligible randomized trials of antibiotic prophylaxis. The panel made a weak recommendation for systemic antibacterial prophylaxis for children receiving intensive chemotherapy for acute myeloid leukemia and relapsed acute lymphoblastic leukemia (ALL). Weak recommendations against the routine use of systemic antibacterial prophylaxis were made for children undergoing induction chemotherapy for ALL, autologous HSCT and allogeneic HSCT. A strong recommendation against its routine use was made for children whose therapy is not expected to result in prolonged severe neutropenia. If used, prophylaxis with levofloxacin was recommended during severe neutropenia.

Conclusions

We present a CPG for systemic antibacterial prophylaxis administration in pediatric cancer and HSCT patients. Future research should evaluate the long-term effectiveness and adverse effects of prophylaxis.

Adverse outcomes associated with the treatment of Toxoplasma infections

Adverse outcomes associated with the treatment of Toxoplasma gondii infections in patients with various health backgrounds have not been characterized. The aim of this study was to identify the adverse outcomes and adverse events associated with the current clinical treatments of Toxoplama gondii infections using real world data reported to the FDA adverse event reporting system (FAERS). Data submitted to FAERS between 2013 and 2019 was retrieved and analyzed. Reporting odds ratio of death was calculated for the drugs having ≥ 25 reports of adverse outcomes. The adverse event profiles for the same drugs were analyzed and the reporting odds ratio was calculated relative to all other drugs used in the treatment of Toxoplasma infections. There were 503 cases reporting the treatment of Toxoplasma infections in the FAERS database. Death (DE) was the adverse outcome in 102 reports, of which 23 (22.5%) anti-Toxoplasma drugs were listed as the primary suspect drug (PS). Clindamycin (2.04; 1.07–3.90) followed by pyrimethamine (1.53; 0.99–2.36) were the most likely to be associated with death. Adverse events analysis suggest that sulfonamides formulations may have a less favorable safety profile. Our study represents the first real-world analysis of adverse outcomes and events associated with the treatment of Toxoplasma infections. Our findings support the need to better understand the current first-line agents for Toxoplasma infections, in addition to underscoring the need to identify safer regimens.

Efficient removal of pharmaceuticals from water using graphene nanoplatelets as adsorbent

Recently, pharmaceutical pollutants in water have emerged as a global concern as they give threat to human health and the environment. In this study, graphene nanoplatelets (GNPs) were used to efficiently remove antibiotics sulfamethoxazole (SMX) and analgesic acetaminophen (ACM) as pharmaceutical pollutants from water by an adsorption process. GNPs; C750, C300, M15 and M5 were characterized by high-resolution transmission electron microscopy, Raman spectroscopy, X-ray diffraction and Brunauer-Emmett-Teller. The effects of several parameters viz. solution pH, adsorbent amount, initial concentration and contact time were studied. The parameters were optimized by a batch adsorption process and the maximum removal efficiency for both pharmaceuticals was 99%. The adsorption kinetics and isotherms models were employed, and the experimental data were best analysed with pseudo-second kinetic and Langmuir isotherm with maximum adsorption capacity (Qm) of 210.08 mg g-1 for SMX and 56.21 mg g-1 for ACM. A regeneration study was applied using different eluents; 5% ethanol-deionized water 0.005 M NaOH and HCl. GNP C300 was able to remove most of both pollutants from environmental water samples. Molecular docking was used to simulate the adsorption mechanism of GNP C300 towards SMX and ACM with a free binding energy of -7.54 kcal mol-1 and -5.29 kcal mol-1, respectively, which revealed adsorption occurred spontaneously.

Staphylococcal Skin and Soft Tissue Infections

Staphylococcus aureus is the most common bacteria causing purulent skin and soft tissue infections. Many disease-causing S aureus strains are methicillin resistant; thus, empiric therapy should be given to cover methicillin-resistant S aureus. Bacterial wound cultures are important for characterizing local susceptibility patterns. Definitive antibiotic therapy is warranted, although there are no compelling data demonstrating superiority of any one antibiotic over another. Antibiotic choice is predicated by the infection severity, local susceptibility patterns, and drug-related safety, tolerability, and cost. Response to therapy is expected within the first days; 5 to 7 days of therapy is typically adequate to achieve cure.

Antimicrobial pharmacokinetics and preclinical in vitro models to support optimized treatment approaches for uncomplicated lower urinary tract infections

INTRODUCTION

Urinary tract infections (UTIs) are extremely common. Millions of people, particularly healthy women, are affected worldwide every year. One-in-two women will have a recurrence within 12-months of an initial UTI. Inadequate treatment risks worsening infection leading to acute pyelonephritis, bacteremia and sepsis. In an era of increasing antimicrobial resistance, it is critical to provide optimized antimicrobial treatment.

AREAS COVERED

Literature was searched using PubMed and Google Scholar (up to 06/2020), examining the etiology, diagnosis and oral antimicrobial therapy for uncomplicated UTIs, with emphasis on urinary antimicrobial pharmacokinetics (PK) and the application of dynamic in vitro models for the pharmacodynamic (PD) profiling of pathogen response.

EXPERT OPINION

The majority of antimicrobial agents included in international guidelines were developed decades ago without well-described dose-response relationships. Microbiology laboratories still apply standard diagnostic methodology that has essentially remained unchanged for decades. Furthermore, it is uncertain how relevant standard in vitro susceptibility is for predicting antimicrobial efficacy in urine. In order to optimize UTI treatments, clinicians must exploit the urine-specific PK of antimicrobial agents. Dynamic in vitro models are valuable tools to examine the PK/PD and urodynamic variables associated with UTIs, while informing uropathogen susceptibility reporting, optimized dosing schedules, clinical trials and treatment guidelines.

Regional Differences in Penetration of the Protein Stabilizer Trimethoprim (TMP) in the Rat Central Nervous System

Regulating gene expression at the protein level is becoming increasingly important for answering basic questions in neurobiology. Several techniques using destabilizing domains (DD) on transgenes, which can be activated or deactivated by specific drugs, have been developed to achieve this goal. A DD from bacterial dihydrofolate reductase bound and stabilized by trimethoprim (TMP) represents such a tool. To control transgenic protein levels in the brain, the DD-regulating drugs need to have sufficient penetration into the central nervous system (CNS). Yet, very limited information is available on TMP pharmacokinetics in the CNS following systemic injection. Here, we performed a pharmacokinetic study on the penetration of TMP into different CNS compartments in the rat. We used mass spectrometry to measure TMP concentrations in serum, cerebrospinal fluid (CSF) and tissue samples of different CNS regions upon intraperitoneal TMP injection. We show that TMP quickly (within 10 min) penetrates from serum to CSF through the blood-CSF barrier. TMP also shows quick penetration into brain tissue but concentrations were an order of magnitude lower compared to serum or CSF. TMP concentration in spinal cord was lower than in any other analyzed CNS area. Nevertheless, effective levels of TMP to stabilize DDs can be reached in the CNS with half-lives around 2 h. These data show that TMP has good and fast penetration properties into the CNS and is therefore a valuable ligand for precisely controlling protein expression in the CNS in rodents.

Antibiotics for complicated urinary tract infection and acute pyelonephritis: A systematic review

BACKGROUND

The increasing rates of antibiotic-resistance in recent years have supported emergence of multiple drug-resistant bacteria. Therefore, antibiotics that are recommended by the current clinical guidelines may not be effective for the treatment of complicated urinary tract infection (UTI) and acute pyelonephritis.

AIM

To determine the clinical efficacy and safety of antibiotics for the treatment of complicated UTI and acute pyelonephritis.

METHOD

A search of PubMed, EMBASE, and Google Scholar was conducted for eligible articles describing the use of antibiotics in managing complicated UTI and acute pyelonephritis. The following keywords were used to perform the literature search: “urinary tract infection”, “complicated UTI”, “pyelonephritis”, “treatment”, and “antibiotics”. Additional articles of interest were retrieved from the reference lists of selected papers. Eligibility criteria for this systematic review were diagnosis of either complicated UTI or acute pyelonephritis and use of antibiotics in management. Clinical trials and observational studies were included, while case reports and reviews were excluded. The methodological quality of clinical trials and observational studies was assessed. A descriptive approach was adopted to analyze the data, due to the variation of methodology and interventions.

RESULT

A total of 183 studies were screened, and 8 matched all the eligibility criteria and were included in this review. The antibiotics used included ceftazidime-avibactam, doripenem, levofloxacin, meropenem-vaborbactam, piperacillin-tazobactam, plazomicin, tazobactam-ceftolozane, and gentamicin. Two clinical trials reported that shorter-duration levofloxacin or non-fluoroquinolone antibiotic treatment was as effective as the duration of antibiotic therapy recommended by the current guidelines in treating complicated UTI and pyelonephritis. Besides that, ceftazidime-avibactam, piperacillin-tazobactam and tazobactam-ceftolozane can be used as alternatives to carbapenem in treating extended-spectrum -lactamase-producing Escherichia coli. The cure rates of complicated UTI and pyelonephritis by meropenem-vaborbactam, piperacillin-tazobactam and tazobactam-ceftolozane was comparable (95.6%-98.4%). Furthermore, levofloxacin had a relatively high rate of adverse events (33.1% and 47.7% in two clinical trials respectively), while tazobactam-ceftolozane had a relatively low rate of adverse events (17.5%). All studies have limitations and a potential for bias.

CONCLUSION

N

Renal Transplant Recipient with Concurrent COVID-19 and Stenotrophomonas maltophilia Pneumonia Treated with Trimethoprim/Sulfamethoxazole Leading to Acute Kidney Injury: A Therapeutic Dilemma

BACKGROUND Although coronavirus disease 2019 (COVID-19) manifests primarily as a lung infection, its involvement in acute kidney injury (AKI) is gaining recognition and is associated with increased morbidity and mortality. Concurrent infection, which may require administration of a potentially nephrotoxic agent, can worsen AKI and lead to poor outcomes. Stenotrophomonas maltophilia is a multidrug-resistant gram-negative bacillus associated with nosocomial infections, especially in severely immunocompromised and debilitated patients. Trimethoprim/sulfamethoxazole combination (TMP/SMX) is considered the treatment of choice but can itself lead to AKI, posing a significant challenge in the management of patients with concomitant COVID-19 and S. maltophilia pneumonia. CASE REPORT A 64-year-old male with end-stage renal disease and post renal transplant presented with severe respiratory symptoms of COVID-19 and was intubated upon admission. His renal functions were normal at the time of admission. The patient subsequently developed superimposed bacterial pneumonia with S. maltophilia requiring administration of TMP/SMX. However, TMP/SMX led to the development of AKI, which continued to worsen despite appropriate management including hemodialysis. This coincided with and most likely resulted in the patient's clinical deterioration and ultimate death. CONCLUSIONS The etiology of kidney disease involvement in patients with COVID-19 is still evolving and appears to be multifactorial. The condition can significantly worsen especially when nephrotoxic agents are given, probably due to a cumulative or synergistic effect. Great caution should be taken when administering nephrotoxic agents in the setting of COVID-19 as it can lead to adverse patient outcomes.

Trimethoprim–Sulfamethoxazole: new lessons on an old antimicrobial; a retrospective analysis

Objective

This study aimed to evaluate the appropriateness of TMP-SMX prescriptions as part of drug utilization review.

Method

Charts of all patients (adults and paediatrics) admitted to Hamad General Hospital who received TMP-SMX from December 2016 till May 2017 were reviewed and assessed for prescribing/administering appropriateness.

Key findings

Total of 149 patients was included (55 paediatrics, 94 adults). None of the adults were tested for G6PD before initiating TMP-SMX, while most of the paediatrics (85.5%) had a record of G6PD status. Dosing of TMP-SMX was considered appropriate in 65% of the paediatrics, whereas only in 49% of adults. Bone infections and S. maltophilia were the uppermost indications associated with inappropriate dosing (85.7 and 74.3%, respectively). Errors in dosing were observed to be higher with intravenous formulations (51.2%) compared to orals (35.2%). With regard to pharmacy verification/dispensing, 135 out of 149 orders (90.6%) were correctly verified/dispensed. Appropriateness of the prescribed dosing was only significantly affected by the indication for TMP-SMX use (P-value &lt; 0.001), while the route of administration was the only variable that correlated significantly with pharmacy verification/dispensing errors (P-value 0.032).

Conclusion

TMP-SMX prescribing patterns were not always optimum. The results of this study should promote healthcare facilities to review/ensure optimal utilization of TMP-SMX which can consequently help in diminishing burden of antimicrobial resistance.

Unexpected Cardiomyopathy and Cardiac Dysfunction after Administration of Sulfadiazine-trimethoprim Medicated Diet to ICR mice (Mus musculus)

For many years, the University of Chicago administered sulfamethoxazole-trimethoprim sulfate (SMZ-TMP) oral suspension to select immunocompromised mouse colonies via the drinking water. In 2014, SMZ-TMP oral suspension was placed on back-order and medicated diet with a different sulfonamide, sulfadiazine-trimethoprim (SDZ-TMP) was used as a replacement. Months after this transition, sentinel mice from the same room as one of the remaining immunocompromised colonies on this diet were found dead or appeared sick. Necropsies revealed cardiomegaly, and histology confirmed myocardial fibrosis in the first 4 sentinel mice examined, consistent with cardiomyopathy. Subsequent sequential monitoring of 2 sentinel mice via echocardiography showed their progression toward decreased cardiac function. Investigation of the housing room revealed that the sentinel mice had been accidently placed on SDZ-TMP diet upon entering the colony housing room. This case report describes cardiomyopathy in 6 ICR mice after long term consumption of SDZ-TMP medicated feed.

D-mannose vs other agents for recurrent urinary tract infection prevention in adult women: a systematic review and meta-analysis

OBJECTIVE

We performed a systematic review and meta-analysis to determine whether D-mannose reduces urinary tract infection recurrence (ie, cumulative incidence) in adult women with recurrent urinary tract infection compared with other prevention agents. Secondary outcomes included side effects and compliance with D-mannose use.

DATA SOURCES

Ovid Medline 1946-, Embase 1947-, Scopus 1823-, Cochrane Library, Web of Science 1900-, and ClinicalTrials.gov were searched through 4/15/2020.

STUDY ELIGIBILITY CRITERIA

Systematic review inclusion: randomized controlled trials, prospective cohorts, and retrospective cohorts written in English of women ≥18 years old with recurrent urinary tract infection in which D-mannose was utilized as an outpatient prevention regimen. Systematic review exclusion: lab or animal-based research, study protocols only, and conference abstracts. Meta-analysis inclusion: stated D-mannose dose, follow-up time ≥6 months, a comparison arm to D-mannose, and data available from women ≥18 years of age.

STUDY APPRAISAL AND SYNTHESIS METHODS

Two independent reviewers made abstract, full text, and data extraction decisions. Study methodologic quality was assessed using the Cochrane Risk of Bias tool. Relative risks, confidence intervals, and heterogeneity were computed.

RESULTS

Searches identified 776 unique citations. Eight publications met eligibility: 2 using D-mannose only; 6 using D-mannose combined with another treatment. Seven studies were prospective: 2 randomized controlled trials, 1 randomized cross-over trial, and 4 prospective cohort studies. One retrospective cohort study was included. Three studies met meta-analysis eligibility (1 randomized controlled trial, 1 randomized cross-over trial, and 1 prospective cohort). Pooled relative risk of urinary tract infection recurrence comparing D-mannose to placebo was 0.23 (95% confidence interval, 0.14-0.37; heterogeneity=0%; D-mannose n=125, placebo n=123). Pooled relative risk of urinary tract infection recurrence comparing D-mannose to preventative antibiotics was 0.39 (95% confidence interval, 0.12-1.25; heterogeneity=88%; D-mannose n=163, antibiotics n=163). Adverse side effects were reported in 2 studies assessing D-mannose only (1 study (n=10) reported none; the other reported a low incidence (8/103 participants) of diarrhea). Two studies reported compliance, which was high.

CONCLUSION

D-mannose appears protective for recurrent urinary tract infection (vs placebo) with possibly similar effectiveness as antibiotics. Overall, D-mannose appears well tolerated with minimal side effects-only a small percentage experiencing diarrhea. Meta-analysis interpretation must consider the small number of studies with varied study design and quality and the overall small sample size.

Fosfomycin for bacterial prostatitis: a review

There has been growing interest in fosfomycin for the treatment of bacterial prostatitis due to evidence suggesting that it achieves adequate prostatic concentrations for antimicrobial effect, has activity against resistant micro-organisms, and has a low-toxicity profile. This review evaluated the current clinical evidence for fosfomycin in acute and chronic bacterial prostatitis to elucidate the clinical implications of fosfomycin in an era of increasing antimicrobial resistance. PubMed, Scopus, EMBASE, Web of Science, Google Scholar and ClinicalTrials.gov were searched for studies published in the English language from January 1984 to November 2019. The inclusion criteria were met if the study reported the use of fosfomycin (more than one dose) to treat bacterial prostatitis. Ten observational studies were identified that met the inclusion criteria. The evidence for the use of fosfomycin in acute bacterial prostatitis is sparse. The majority of the available evidence is for chronic bacterial prostatitis caused by Escherichia coli. Despite the implementation of variable dosing regimens, extended courses of fosfomycin appear to be safe and effective in achieving clinical and microbiological cure. In these studies, the use of fosfomycin was restricted to cases of treatment failure, intolerance to first-line therapy, or multi-resistant organisms. However, given the development of resistant organisms and the undesirable adverse effects of many first-line therapeutic options, fosfomycin has the potential to be considered as an effective first-line alternative for acute and chronic bacterial prostatitis in the future. Further studies, including randomized controlled trials, would be helpful to firmly establish its optimal dosing regimen, efficacy and place in therapy.

Rare case of pseudohypoaldosteronism in a neonate secondary to congenital hydrometrocolpos

Pseudohypoaldosteronism (PHA) due to obstructive uropathy, urinary tract infections and congenital urogenital malformations has been reported in the literature; however, there are no reports of PHA associated with hydrometrocolpos due to a common urogenital tract. Hydrometrocolpos is a condition resulting in distension of the vagina and uterus due to accumulation of secretions (other than blood), caused by increased oestrogenic stimulation and vaginal outflow obstruction. We report on a neonatal case of PHA caused by recurrent hydrometrocolpos presenting with vomiting and poor weight gain. There was significant hyponatraemia, hyperkalaemia, and anaemia requiring medical stabilisation prior to surgery. The mechanism by which PHA occurs in obstruction involves renal tubular dysfunction due to pressure from hydronephrosis and the release of intrarenal cytokines. In addition, there is an immature or resistant renal tubular responsiveness to aldosterone during infancy. Clinicians should be aware of this uncommon but serious presentation.

Risk Factors and Prevention of Pneumocystis jirovecii Pneumonia in Patients With Autoimmune and Inflammatory Diseases

Patients with autoimmune and/or inflammatory diseases (AIIDs) are prone to serious infectious complications such as Pneumocystis jirovecii pneumonia (PJP). In non-HIV patients, the prognosis is poorer, and diagnostic tests are of lower sensitivity. Given the low incidence of PJP in AIIDs, with the exception of granulomatosis with polyangiitis, and the non-negligible side effects of chemoprophylaxis, routine prescription of primary prophylaxis is still debated. Absolute peripheral lymphopenia, high doses of corticosteroids, combination with other immunosuppressive agents, and concomitant lung disease are strong predictors for the development of PJP and thus should warrant primary prophylaxis. Trimethoprim-sulfamethoxazole is considered first-line therapy and is the most extensively used drug for PJP prophylaxis. Nevertheless, it may expose patients to side effects. Effective alternative drugs such as atovaquone or aerosolized pentamidine could be used when trimethoprim-sulfamethoxazole is not tolerated or contraindicated. No standard guidelines are available to guide PJP prophylaxis in patients with AIIDs. This review covers the epidemiology, risk factors, and prevention of pneumocystis in the context of AIIDs.

Pneumocystis jirovecii in immunocompromised patients with rheumatic diseases

Infections, including opportunistic infections, are a major and frequent cause of morbidity and mortality in patients with systemic autoimmune and rheumatic diseases. Pneumocystis jirovecii pneumonia, classically considered to be typical of HIV patients, transplanted patients or patients treated with oncological chemotherapy, is appearing increasingly frequently in these patients. Therefore, rheumatologists should know its mechanism of production, clinical manifestations, treatment and prophylaxis, all of which are addressed in this review.

Hyponatremia Associated with Prophylactic Low-Dose Trimethoprim during Systemic Corticosteroid Therapy for AQP4-Positive Optic Neuritis in a Diabetic Patient

Hyponatremia associated with low-dose trimethoprim in patients on concomitant systemic corticosteroid therapy has rarely been reported. Here, we describe a 57-year-old woman with a history of diabetes mellitus and hypertension treated with telmisartan, who presented with progressive visual impairment of the left eye due to anti-aquaporin-4 antibody-positive optic neuritis. The patient received pulsed intravenous methylprednisolone followed by oral prednisolone at 30 mg/day and trimethoprim-sulfamethoxazole prophylaxis (160 mg and 800 mg daily). Her serum sodium level steadily decreased, and the potassium level was slightly elevated despite well-preserved renal function. This state persisted even after telmisartan discontinuation. In addition to hypotonic hyponatremia (125 mEq/L) with natriuresis, hyperkalemic renal tubular acidosis was diagnosed based on normal anion gap metabolic acidosis and hyperkalemia with low urinary potassium excretion. After trimethoprim-sulfamethoxazole cessation, electrolytes and acid-base imbalances swiftly recovered. We can conclude that caution must be exercised when treating such patients, because even low-dose trimethoprim may cause hyponatremia concomitant with hyperkalemic renal tubular acidosis, despite the mineralocorticoid effects of systemic corticosteroids.

Challenges in treatment of disseminated nocardiosis in an elderly patient with renal failure on corticosteroids: a case report

We report the case of a 71-year-old Japanese man with a history of chronic kidney disease and sarcoidosis receiving chronic corticosteroids who presented with disseminated Nocardia brasiliensis infection. He initially showed improvement with empiric antimicrobial therapy including trimethoprim-sulfamethoxazole. However, he deteriorated after modifying the empiric regimen due to complicated hyperkalemia and ultimately died. In general, elderly patients have decreased renal function. Standard therapy for nocardiosis with trimethoprim-sulfamethoxazole may not be used for a prolonged period of time. This case emphasizes the challenges and importance of prudent selection of empiric antimicrobial therapy for disseminated nocardiosis in elderly patients with underlying kidney disease.

Low-Dose TMP-SMX in the Treatment of Pneumocystis jirovecii Pneumonia: A Systematic Review and Meta-analysis

Background

Pneumocystis jirovecii pneumonia (PJP) remains a common and highly morbid infection for immunocompromised patients. Trimethoprim-sulfamethoxazole (TMP-SMX) is the antimicrobial treatment of choice. However, treatment with TMP-SMX can lead to significant dose-dependent renal and hematologic adverse events. Although TMP-SMX is conventionally dosed at 15–20 mg/kg/d of trimethoprim for the treatment of PJP, reduced doses may be effective and carry an improved safety profile.

Methods

We conducted a systematic search in the Medline, Embase, and Cochrane Library databases from inception through March 2019 for peer-reviewed studies reporting on reduced doses of TMP-SMX (15 mg/kg/d of trimethoprim or less) for the treatment of PJP. PRISMA, MOOSE, and Cochrane guidelines were followed. Gray literature was excluded.

Results

Ten studies were identified, and 6 were included in the meta-analysis. When comparing standard doses with reduced doses of TMP-SMX, there was no statistically significant difference in mortality (absolute risk difference, –9% in favor of reduced dose; 95% confidence interval [CI], –27% to 8%). When compared with standard doses, reduced doses of TMP-SMX were associated with an 18% (95% CI, –31% to –5%) absolute risk reduction of grade ≥3 adverse events.

Conclusions

In this systematic review, treatment of PJP with doses of ≤10 mg/kg/d of trimethoprim was associated with similar rates of mortality when compared with standard doses and with significantly fewer treatment-emergent severe adverse events. Although limited by the observational nature of the studies included, this review provides the most current available evidence for the optimal dosing of TMP-SMX in the treatment of PJP.

Evaluating the risk of hyperkalaemia and acute kidney injury with cotrimoxazole: a retrospective observational study

OBJECTIVES

Increasing antimicrobial resistance has renewed interest in older, less used antimicrobials. Cotrimoxazole shows promise; however, hyperkalaemia and acute kidney injury (AKI) are potential complications. Identifying risk factors for and quantification of these events is required for safe use. This study aimed to evaluate predictors of cotrimoxazole-associated AKI and hyperkalaemia in a clinical setting.

METHODS

Patients prescribed cotrimoxazole were identified using electronic healthcare records over 3 years (1 April 2016 to 31 March 2019). Individual risk factors were recognized. Serum creatinine and potassium trends were analysed over the subsequent 21 days. AKI and patients with hyperkalaemia were classified using Kidney Disease Improving Global Outcomes (KDIGO) and laboratory criteria. Univariate and multiple logistic regression analyses were performed.

RESULTS

Among 214 patients prescribed cotrimoxazole, 42 (19.6%, 95% confidence interval (CI) 14.6-25.7) met AKI criteria and 33 (15.4%, 95% CI 11.0-21.1) developed hyperkalaemia. Low baseline estimated glomerular filtration rate (<60 mL/min/1.73 m², odds ratio (OR) 7.78, 95% CI 3.57-16.13, p < 0.0001) and cardiac disorders (OR 2.40, 95% CI 1.17-4.82, p 0.011) predicted AKI, while low baseline estimated glomerular filtration rate (<60 mL/min/1.73 m², OR 6.80, 95% CI 3.09-15.06, p < 0.0001) and higher baseline serum potassium (p 0.001) predicted hyperkalaemia. Low-dose cotrimoxazole (<1920 mg/d) was associated with lower AKI and hyperkalaemia risk (p 0.007 and 0.019 respectively). Early (within the first 2-4 days of therapy) serum creatinine changes predicted AKI (OR 3.65, 95% CI 1.73-7.41, p 0.001), and early serum potassium changes predicted hyperkalaemia (>0.6 mmol/L, OR 2.47, 95% CI 1.14-5.27, p 0.0236).

CONCLUSIONS

Cotrimoxazole-associated AKI and hyperkalaemia is frequent and dose dependent. Renal function, serum potassium and preexisting cardiac disorders should be evaluated before prescribing cotrimoxazole. Serum creatinine and potassium monitoring within first 2 to 4 days of treatment to identify susceptible patients is recommended, and the lowest effective dose ought to be prescribed.

A pooled analysis of patients with wound infections in the Phase 3 REVIVE trials: randomized, double-blind studies to evaluate the safety and efficacy of iclaprim versus vancomycin for treatment of acute bacterial skin and skin structure infections

Introduction. Iclaprim is a diaminopyrimidine antibiotic for the treatment of acute bacterial skin and skin structure infections (ABSSSI) due to Gram-positive pathogens.Aim. This analysis evaluates patients with wound infections from two Phase 3 trials of ABSSSI.Methodology. Six-hundred-two patients with wound infections from two Phase 3, double-blinded, randomized, multicenter, active controlled trials (REVIVE-1/-2) were evaluated in a post hoc analysis of iclaprim 80 mg compared with vancomycin 15 mg kg^-1 administered intravenously every 12 h for 5-14 days. The primary endpoint was to determine whether iclaprim was non-inferior (10 % margin) to vancomycin in achieving a ≥20 % reduction from baseline in lesion size 48-72 h after starting study drug (early clinical response [ECR]). Safety was assessed.Results. In REVIVE-1, ECR was 83.5 % with iclaprim versus 79.7 % with vancomycin (treatment difference 3.77%, 95 % CI -4.50%, 12.04%). In REVIVE-2, ECR was 82.7 % with iclaprim versus 76.3 % with vancomycin (treatment difference 6.38%, 95 % CI -3.35%, 16.12%). In the pooled dataset, iclaprim had similar ECR rates compared with vancomycin among wound infection patients (83.2 % vs 78.2 %) with a treatment difference of 5.01 % (95 % CI -1.29%, 11.32%). The safety profile was similar in iclaprim- and vancomycin-treated patients, except for a higher incidence of diarrhea with vancomycin (n=17) compared with iclaprim (n=6) and fatigue with iclaprim (n=17) compared with vancomycin (n=8).Conclusion. Based on early clinical response, iclaprim achieved non-inferiority to vancomycin with a similar safety profile in patients with wound infections suspected or confirmed as caused by Gram-positive pathogens. Iclaprim may be a valuable treatment option for wound infections.

Design and rationale of a multi-center, pragmatic, open-label randomized trial of antimicrobial therapy - the study of clinical efficacy of antimicrobial therapy strategy using pragmatic design in Idiopathic Pulmonary Fibrosis (CleanUP-IPF) clinical trial

Abstract

Compelling data have linked disease progression in patients with idiopathic pulmonary fibrosis (IPF) with lung dysbiosis and the resulting dysregulated local and systemic immune response. Moreover, prior therapeutic trials have suggested improved outcomes in these patients treated with either sulfamethoxazole/ trimethoprim or doxycycline. These trials have been limited by methodological concerns. This trial addresses the primary hypothesis that long-term treatment with antimicrobial therapy increases the time-to-event endpoint of respiratory hospitalization or all-cause mortality compared to usual care treatment in patients with IPF. We invoke numerous innovative features to achieve this goal, including: 1) utilizing a pragmatic randomized trial design; 2) collecting targeted biological samples to allow future exploration of ‘personalized’ therapy; and 3) developing a strong partnership between the NHLBI, a broad range of investigators, industry, and philanthropic organizations. The trial will randomize approximately 500 individuals in a 1:1 ratio to either antimicrobial therapy or usual care. The site principal investigator will declare their preferred initial antimicrobial treatment strategy (trimethoprim 160 mg/ sulfamethoxazole 800 mg twice a day plus folic acid 5 mg daily or doxycycline 100 mg once daily if body weight is < 50 kg or 100 mg twice daily if ≥50 kg) for the participant prior to randomization. Participants randomized to antimicrobial therapy will receive a voucher to help cover the additional prescription drug costs. Additionally, those participants will have 4–5 scheduled blood draws over the initial 24 months of therapy for safety monitoring. Blood sampling for DNA sequencing and genome wide transcriptomics will be collected before therapy. Blood sampling for transcriptomics and oral and fecal swabs for determination of the microbiome communities will be collected before and after study completion. As a pragmatic study, participants in both treatment arms will have limited in-person visits with the enrolling clinical center. Visits are limited to assessments of lung function and other clinical parameters at time points prior to randomization and at months 12, 24, and 36. All participants will be followed until the study completion for the assessment of clinical endpoints related to hospitalization and mortality events.

Trial Registration

ClinicalTrials.gov identifier NCT02759120.

Dose-Dependent Hyperkalemia Among Hospitalized, HIV-Infected Patients Receiving Sulfamethoxazole/Trimethoprim

Background: Sulfamethoxazole-trimethoprim (SXT) therapy is commonly used in HIV-infected patients and is associated with hyperkalemia and elevated serum creatinine (SCr). Objective: The purpose of this study was to examine the frequency of hyperkalemia and elevated SCr in hospitalized, HIV-infected patients receiving SXT. Methods: This was a retrospective, single-center cohort study. HIV-infected hospitalized patients receiving a minimum of 3 consecutive days of SXT were included. Patients were grouped according to high dose (≥10 mg/kg/d) and low dose (<10 mg/kg/d) trimethoprim. The primary end point was the frequency of hyperkalemia, severe hyperkalemia, and elevated SCr. Secondary end points included an evaluation of concomitant potassium-altering medications and concomitant nephrotoxic drugs. Results: A total of 100 consecutive patients were selected from all possible patients who met inclusion criteria. Overall, 47 patients experienced at least 1 adverse drug event (ADE) of either hyperkalemia or increased SCr, with 20 patients experiencing these ADEs in the low-dose group and 27 patients experiencing these ADEs in the high-dose group (P = 0.229). The ADEs of hyperkalemia or increased SCr occurred after a shorter period (5.5 vs 8.7 days) in the high-dose group (P = 0.049). Overall frequency of elevated SCr was 24% and of elevated serum K was 36%. Hyperkalemia requiring a therapeutic intervention occurred in 12 patients in the high-dose group compared with 2 in the low-dose group (P = 0.009). Conclusion and Relevance: Rates of elevated SCr and hyperkalemia in hospitalized HIV-infected patients receiving SXT are significant. Hyperkalemia requiring intervention is more common in patients receiving high-dose SXT.

Human health risk assessment of antibiotics in binary mixtures for finished drinking water

The present study developed a new step-wise approach to estimate the potential human health risk of antibiotics in binary mixture for drinking water samples for two different sub-populations. Monte Carlo simulation based uncertainty analysis was performed to reduce uncertainty in risk assessment. Human health risk assessment studies were carried out using the acceptable daily intake (ADIs) for exposures of individual antibiotics considering point of departure (POD) and uncertainty factors (UFs). The estimated ADI values were used to estimate the predicted no effect concentrations (PNECs), at or below which no adverse human health effects are anticipated. Hazard quotient (HQ) in risk assessment was calculated as a ratio of environmental concentrations (ECs) and PNECs (EC/PNEC). The study showed that the average HQs values of individual antibiotics in adult and children were found below the acceptable limit, demonstrating no possible human health risk for both the subgroups. HI_interaction values of antibiotics in binary mixture was calculated using HQ values of antibiotics. The study observed that the estimated HI_interaction values of antibiotics in binary mixture was found to be less than 1 for both the sub populations, indicating no potential adverse effects on human health. Concentration of antibiotics was the primary contributor (>65%) to the overall variance in the uncertainty estimates for HQs of individual antibiotics in drinking water for adult and children. The co-occurrence of antibiotics in binary mixture for drinking water samples doesn't possess any possible risk on human health for the studied population.

Heavy metal pollution and co-selection for antibiotic resistance: A microbial palaeontology approach

Frequent and persistent heavy metal pollution has profound effects on the composition and activity of microbial communities. Heavy metals select for metal resistance but can also co-select for resistance to antibiotics, which is a global health concern. We here document metal concentration, metal resistance and antibiotic resistance along a sediment archive from a pond in the North West of the United Kingdom covering over a century of anthropogenic pollution. We specifically focus on zinc, as it is a ubiquitous and toxic metal contaminant known to co-select for antibiotic resistance, to assess the impact of temporal variation in heavy metal pollution on microbial community diversity and to quantify the selection effects of differential heavy metal exposure on antibiotic resistance. Zinc concentration and bioavailability was found to vary over the core, likely reflecting increased industrialisation around the middle of the 20th century. Zinc concentration had a significant effect on bacterial community composition, as revealed by a positive correlation between the level of zinc tolerance in culturable bacteria and zinc concentration. The proportion of zinc resistant isolates was also positively correlated with resistance to three clinically relevant antibiotics (oxacillin, cefotaxime and trimethoprim). The abundance of the class 1 integron-integrase gene, intI1, marker for anthropogenic pollutants correlated with the prevalence of zinc- and cefotaxime resistance but not with oxacillin and trimethoprim resistance. Our microbial palaeontology approach reveals that metal-contaminated sediments from depths that pre-date the use of antibiotics were enriched in antibiotic resistant bacteria, demonstrating the pervasive effects of metal-antibiotic co-selection in the environment.

The anti-MRSA compound 3-O-alpha-L-(2″,3″-di-p-coumaroyl)rhamnoside (KCR) inhibits protein synthesis in Staphylococcus aureus

Methicillin-resistant S aureus (MRSA) contributes to patient mortality and extended hospital stays. 3-O-alpha-L-(2″,3″-di-p-coumaroyl)rhamnoside (KCR) is a natural product antibiotic that is effective against MRSA but has no known mechanism of action (MOA). We used proteomics to identify the MOA for KCR. Methicillin sensitive S aureus and a mixture of four KCR stereoisomers were tested. A time-kill assay was used to choose a 4 h treatment using KCR at 5× its MIC for proteomic analysis. S aureus was treated in triplicate with KCR, oxacillin or vehicle and quantitative proteomic analysis was carried out using isobaric tags and mass spectrometry. 1190 proteins were identified and 552 were affected by KCR (q < 0.01). Ontology analysis identified 6 distinct translation-related categories that were affected by KCR (PIANO, 10% false-discovery rate) including structural constituent of ribosome, translation, rRNA binding, tRNA binding, tRNA processing and aminoacyl-tRNA ligase activity. Median fold changes (KCR vs Control) for small and large ribosomal components were 1.46 and 1.43 respectively. KCR inhibited the production of luciferase protein in an in vitro assay (IC50 39.6 μg/ml). Upregulation of translation-related proteins in response to KCR indicates that KCR acts to disrupt S aureus protein synthesis. This was confirmed with an in vitro transcription/translation assay. SIGNIFICANCE: Methicillin-resistant S aureus (MRSA) contributes to patient mortality and extended hospital stays. 3-O-alpha-L-(2″,3″-di-p-coumaroyl)rhamnoside (KCR) is a natural product antibiotic that is effective against MRSA but has no known mechanism of action (MOA). Using proteomic analysis we determined that KCR acts by inhibiting protein synthesis. KCR is an exciting novel antibiotic and this work represents an important step in its development towards clinical use.

Efficacy of cotrimoxazole (Sulfamethoxazole-Trimethoprim) as a salvage therapy for the treatment of bone and joint infections (BJIs)

INTRODUCTION

Cotrimoxazole (Sulfamethoxazole-Trimethoprim, SXT) has interesting characteristics for the treatment of bone and joint infection (BJI): a broad spectrum of activity with adequate bone diffusion and oral and intravenous formulations. However, its efficacy and safety in BJIs are poorly documented and its use remains limited.

METHODS

We conducted a retrospective study in 2 reference centers for BJIs from 2013 to 2018 among patients treated with SXT for a BJI. Data were collected from patient's medical charts. Outcomes and adverse events were evaluated at day (D)7, D45 and D90.

RESULTS

We analyzed 51 patients with a mean age of 60 ± 20 (SD) years of which 76% presented with an orthopedic device infection (ODI). Gram-negative bacilli (GNB) were involved in 47% of BJIs (n = 24). Moreover, they were often polymicrobial infections (41%). Doses of SXT ranged from 800/160mg bid (61%; n = 31) to 800/160mg tid (39%; n = 20). Median SXT treatment duration was 45 days (IQR 40-45). SXT was part of a dual therapy in 84% of patients (n = 43), associated mainly with fluoroquinolones (n = 17) or rifampicin (n = 14). Outcome was favorable at D7 in 98% (n = 50), at D45 in 88.2% (n = 45) and at D90 in 78.4% (n = 40). The second agent combined with SXT was not an independent factor of favorable outcome (p = 0.97). Adverse events were reported in 8% (n = 4) of patients, with a median of 21 days (IQR 20-30) from SXT initiation and led to discontinuation (n = 3).

CONCLUSION

SXT appears to be effective for treatment of BJIs as a salvage therapy, even in GNB or polymicrobial infection, including ODI. Further data are needed to confirm SXT efficacy as an alternative oral regimen in BJIs.

Folic Acid Antagonists: Antimicrobial and Immunomodulating Mechanisms and Applications

: Bacterial, protozoan and other microbial infections share an accelerated metabolic rate. In order to ensure a proper functioning of cell replication and proteins and nucleic acids synthesis processes, folate metabolism rate is also increased in these cases. For this reason, folic acid antagonists have been used since their discovery to treat different kinds of microbial infections, taking advantage of this metabolic difference when compared with human cells. However, resistances to these compounds have emerged since then and only combined therapies are currently used in clinic. In addition, some of these compounds have been found to have an immunomodulatory behavior that allows clinicians using them as anti-inflammatory or immunosuppressive drugs. Therefore, the aim of this review is to provide an updated state-of-the-art on the use of antifolates as antibacterial and immunomodulating agents in the clinical setting, as well as to present their action mechanisms and currently investigated biomedical applications.

Comparative In Vivo Antibacterial Activity of Human-Simulated Exposures of Cefiderocol and Ceftazidime against Stenotrophomonas maltophilia in the Murine Thigh Model

Cefiderocol is a novel siderophore cephalosporin that utilizes bacterial ferric iron transports to cross the outer membrane. Cefiderocol shows high stability against all classes of β-lactamases, rendering it extremely potent against carbapenem- and multidrug-resistant Gram-negative organisms. Using a neutropenic murine thigh model, we compared the efficacies of human-simulated exposures of cefiderocol (2 g Q8H 3 h infusion) and ceftazidime (2 g Q8H 2 h infusion) against Stenotrophomonas maltophilia, an emerging opportunistic Gram-negative organism associated with serious and often fatal nosocomial infections. Twenty-four S. maltophilia isolates were studied, including isolates resistant to ceftazidime, trimethoprim-sulfate, and/or levofloxacin. The thighs were inoculated with bacterial suspensions of 10⁸ CFU/mL and the human-simulated regimens were administered over 24 h. Efficacy was measured as the change in log₁₀CFU/thigh at 24 h compared with 0 h controls. Cefiderocol human-simulated exposure demonstrated potent bacterial killing; mean bacterial reduction at 24 h was -2.67 ± 0.68 log₁₀CFU/thigh with ≥ 2 log-reduction achieved in 21 isolates (87.5%) and ≥ 1 log-reduction achieved in the remaining three isolates (12.5%). In comparison, ceftazidime human-simulated exposure produced mean bacterial reduction of -1.38 ± 1.49 log₁₀CFU/thigh among 10 ceftazidime-susceptible isolates and mean bacterial growth of 0.64 ± 0.79 log₁₀CFU/thigh among 14 ceftazidime-non-susceptible isolates. While ceftazidime showed modest efficacy against most susceptible isolates, humanized cefiderocol exposures resulted in remarkable in vivo activity against all S. maltophilia isolates examined, inclusive of ceftazidime-non-susceptible isolates. The potent in vitro and in vivo activity of cefiderocol supports the development of this novel compound for managing S. maltophilia infections.

Risk Factors for Pneumocystis jirovecii Pneumonia in Patients With Rheumatoid Arthritis and a Prophylactic Indication of Trimethoprim/Sulfamethoxazole

BACKGROUND/OBJECTIVES

Immunosuppressant medications (ISPs) increase the occurrence of Pneumocystis jirovecii pneumonia (PCP) in rheumatoid arthritis (RA) patients. The prophylactic administration of trimethoprim/sulfamethoxazole (TMP/SMX) for PCP is effective but has serious adverse effects and so should be selectively used for patients at high risk. The aims of this study were to clarify the risk factors for PCP in RA patients and to establish the indications for administering TMP/SMX.

METHODS

This retrospective cohort study analyzed data from 2640 patients (2010-2014) diagnosed as having RA who had not received a prophylactic administration of TMP/SMX. The risk factors for PCP were evaluated by comparing the clinical parameters between patients with PCP (PCP group, n = 19) and those without (non-PCP group, n = 2621).

RESULTS

The PCP group was older (70 vs. 64 years), received higher doses of prednisolone (6.2 vs. 2.4 mg/d) and methotrexate (7.7 vs. 5.2 mg/wk), and had a greater number of ISPs (1.3 vs. 0.8) (p < 0.05). We stratified the PCP risk using a scoring system based on odds ratios (ORs) calculated for these parameters (methotrexate ≥6 mg/wk OR = 4.5, 1 point; age ≥65 years, OR = 3.7, 1 point; ≥2 ISPs, OR = 3.7, 1 point; prednisolone ≥5 mg/d, OR = 12.4, 3 points). The incidence of PCP among patients scoring 0 to 2 points was 0.04%; 3 to 4 points, 2.3%; and 5 points or more, 5.8%.

CONCLUSIONS

The prophylactic administration of TMP/SMX for PCP is recommended for RA patients who score at least 5 points with our system.

Structure-Based Design of Dimeric Bisbenzimidazole Inhibitors to an Emergent Trimethoprim-Resistant Type II Dihydrofolate Reductase Guides the Design of Monomeric Analogues

The worldwide use of the broad-spectrum antimicrobial trimethoprim (TMP) has induced the rise of TMP-resistant microorganisms. In addition to resistance-causing mutations of the microbial chromosomal dihydrofolate reductase (Dfr), the evolutionarily and structurally unrelated type II Dfrs (DfrBs) have been identified in TMP-resistant microorganisms. DfrBs are intrinsically TMP-resistant and allow bacterial proliferation when the microbial chromosomal Dfr is TMP-inhibited, making these enzymes important targets for inhibitor development. Furthermore, DfrBs occur in multiresistance plasmids, potentially accelerating their dissemination. We previously reported symmetrical bisbenzimidazoles that are the first selective inhibitors of the only well-characterized DfrB, DfrB1. Here, their diversification provides a new series of inhibitors (K _i = 1.7-12.0 μM). Our results reveal two prominent features: terminal carboxylates and inhibitor length allow the establishment of essential interactions with DfrB1. Two crystal structures demonstrate the simultaneous binding of two inhibitor molecules in the symmetrical active site. Observations of those dimeric inhibitors inspired the design of monomeric analogues, binding in a single copy yet offering similar inhibition potency (K _i = 1.1 and 7.4 μM). Inhibition of a second member of the DfrB family, DfrB4, suggests the generality of these inhibitors. These results provide key insights into inhibition of the highly TMP-resistant DfrBs, opening avenues to downstream development of antibiotics for combatting this emergent source of resistance.

Updates on Nocardia Skin and Soft Tissue Infections in Solid Organ Transplantation

PURPOSE OF REVIEW

Due to their immunocompromised status, solid organ transplant (SOT) recipients are at risk for Nocardia infections. These infections often necessitate early invasive diagnostics alongside prolonged, often combination antimicrobial therapy. This review summarizes the importance of this pathogen in skin and soft tissue infections (SSTIs) in SOT recipients inclusive of recently reported cases in the literature and an update on the epidemiology, diagnostics, and management.

RECENT FINDINGS

Six studies with 13 isolated SSTIs due to Nocardia have been published in the last 5 years in SOT recipients. The most common underlying type of transplant was kidney and time from transplantation to infection varied from 6 months to 16 years. Misdiagnosis was frequent. Available identified species included N. brasiliensis (2), N. farcinica (2), N. flavorosea (1), N. abscessus (1), N. anaemiae (1), N. asteroides (1), N. nova (1), and N. vinacea (1). Treatment choice and duration varied widely, and trimethoprim-sulfamethoxazole was utilized most often with no documented infection relapse. Nocardia SSTIs can occur both in isolation and as a component of a disseminated infection. Overall, isolated Nocardia SSTIs are uncommon in SOT recipients and are often initially misdiagnosed. They present multiple challenges to the clinician including evaluation for potential co-pathogens and/or non-infectious processes and ruling out the presence of disseminated infection. While trimethoprim-sulfamethoxazole remains the agent of choice for management of most isolated SSTIs, therapy must be tailored to the individual patient based on species-specific susceptibility patterns and formal susceptibility testing, site(s) of infection, and patient tolerability.

A Pooled Analysis of the Safety and Efficacy of Iclaprim Versus Vancomycin for the Treatment of Acute Bacterial Skin and Skin Structure Infections in Patients With Intravenous Drug Use: Phase 3 REVIVE Studies

PURPOSE

This analysis evaluates the efficacy and safety of iclaprim versus vancomycin for the treatment of acute bacterial skin and skin structure infections (ABSSSIs) in patients who were intravenous drug users (IVDUs).

METHODS

A total of 621 patients who were IVDUs from 2 parallel Phase III, double-blind, randomized (1:1), active-controlled, multinational, multicenter trials (REVIVE-1 and REVIVE-2) were analyzed separately and pooled. This post hoc analysis summarizes the efficacy and safety profile of iclaprim 80 mg fixed dose compared with vancomycin 15 mg/kg administered intravenously during 2 h every 12 h for 5-14 days among this population. The primary end point of these studies was to determine whether iclaprim was noninferior (10% margin) to vancomycin in achieving a ≥20% reduction in lesion size at 48-72 h after initiation of treatment with the study drug (early clinical response) in the intent-to-treat population. The safety profile was assessed based on adverse events and laboratory parameters.

FINDINGS

Iclaprim had higher early clinical response rates (85.8%; 95% CI, 81.5%-89.4%) compared with vancomycin (79.8%; 95% CI, 74.8%-84.2%) among patients with ABSSSIs who were IVDUs, with a treatment difference of +6.00% (95% CI, 0.06-12.0). The safety profile was similar in the iclaprim and vancomycin arms, with 3.7% and 5.0%, respectively, of patients discontinuing study therapy because of adverse events and 1.9% and 3.4%, respectively, of patients developing serious adverse events.

IMPLICATIONS

Iclaprim had a higher early clinical response rate and favorable safety profile compared with vancomycin for the treatment of ABSSSIs in patients who were IVDUs. Iclaprim may be a valuable treatment option for ABSSSIs in this patient population.

Safety and efficacy of prophylaxis for Pneumocystis jirovecii pneumonia involving trimethoprim-sulfamethoxazole dose reduction in kidney transplantation

Background

Trimethoprim-sulfamethoxazole (TMP-SMX) is the drug of choice for anti-Pneumocystis jirovecii pneumonia (PcP) prophylaxis in kidney transplant recipients (KTR). Post-transplant management balances preventing PcP with managing TMP-SMX-related adverse effects. TMP-SMX dose reduction addresses adverse effects but its implications to incident PcP are unclear.

Methods

We performed a retrospective review of all patients transplanted between 2011 and 2015 prescribed daily single strength TMP-SMX for twelve months post-transplantation as PcP prophylaxis. Actual TMP-SMX dose and duration, adverse effects, number of dose reductions and reasons, and PcP events were captured. Multivariate logistic regression analyses for risk factors associated with dose reduction were performed.

Results

Of 438 KTR, 233 (53%) maintained daily TMP-SMX and 205 (47%) sustained ≥1 dose reduction, with the point prevalence of a reduced dose regimen being between 18 and 25%. Median duration for daily TMP-SMX was 8.45/12 months, contributing 4137 patient-months daily TMP-SMX and 1110 patient-months with a reduced dose. PcP did not occur in any patients. There were 84 documented dose reductions for hyperkalemia and 102 for leukopenia, with 12 and 7 patients requiring TMP-SMX cessation. In multivariate analysis, a living donor transplant protected against hyperkalemia (Odds Ratio 0.46, 95% CI 0.26–0.83, p < 0.01) while acute rejection risked leukopenia (Odds Ratio 3.31, 95% CI 1.39–7.90, p = 0.006).

Conclusions

TMP-SMX dose reduction is frequent in the first post-transplant year but PcP does not occur. To limit the need for TMP-SMX dose reduction due to adverse effects, a clinical trial comparing daily to thrice weekly single strength TMP-SMX in de-novo KTR is justified.

In Vitro Activity of Iclaprim against Isolates in Two Phase 3 Clinical Trials (REVIVE-1 and -2) for Acute Bacterial Skin and Skin Structure Infections

Iclaprim, a selective bacterial dihydrofolate reductase inhibitor, and other antibiotics were tested against Gram-positive isolates from two phase 3 studies of acute bacterial skin and skin structure infections (ABSSSIs) (REVIVE-1 and -2). Seven hundred ninety baseline isolates, including Staphylococcus aureus, β-hemolytic streptococci, and Streptococcus anginosus group, underwent antibacterial susceptibility testing. Iclaprim had an MIC₉₀ of 0.12 μg/ml for S. aureus (0.12 μg/ml for methicillin susceptible, 0.25 μg/ml for methicillin resistant), 0.25 μg/ml for β-hemolytic streptococci, and 0.008 μg/ml for S. anginosus group. Iclaprim demonstrated potent activity against these Gram-positive ABSSSI isolates.

Disseminated nocardiosis with Nocardia brasiliensis bacteremia in a patient with rheumatoid arthritis using tocilizumab

Here, we present a case of disseminated nocardiosis, involving pneumonia, percutaneous abscess, and bacteremia, in a 67-year-old Japanese woman. She had also been treated for rheumatoid arthritis with prednisolone, methotrexate, and tocilizumab (interleukin-6 receptor inhibitor). Based on the 16S rRNA sequence analysis and a blast search, we identified the isolate as Nocardia brasiliensis. We discontinued methotrexate and tocilizumab on admission, and administered intravenous antimicrobial combination therapy for 6 weeks, followed by oral trimethoprim-sulfamethoxazole for 12 months, in total. Nocardia bacteremia is rare, often difficult to diagnose, and substantially fatal. However, due to our prompt diagnosis within one day of the onset of symptoms, and administration of appropriate treatment based on antimicrobial susceptibilities, this patient succeeded in surviving the infection. Not only microbiologists but also clinicians should be aware of the characteristic bacterial form of Gram/Kinyoun staining for early recognition of nocardiosis.

Fluoroquinolones versus trimethoprim-sulfamethoxazole for the treatment of Stenotrophomonas maltophilia infections: a systematic review and meta-analysis

BACKGROUND

Fluoroquinolones are a popular alternative to trimethoprim-sulfamethoxazole for Stenotrophomonas maltophilia infections.

OBJECTIVES

To compare the effects of fluoroquinolones and trimethoprim-sulfamethoxazole on mortality of S. maltophilia infections.

DATA SOURCES

PubMed and EMBASE.

STUDY ELIGIBILITY CRITERIA

Clinical studies reporting mortality outcomes of S. maltophilia infections.

PARTICIPANTS

Patients with clinical infections caused by S. maltophilia.

INTERVENTIONS

Fluoroquinolone monotherapy in comparison with trimethoprim-sulfamethoxazole monotherapy.

METHODS

Systematic review with meta-analysis technique.

RESULTS

Seven retrospective cohort and seven case-control studies were included. Three cohort studies were designed to compare the two drugs, whereas others had other purposes. A total of 663 patients were identified, 332 of which were treated with trimethoprim-sulfamethoxazole (50.1%) and 331 with fluoroquinolones (49.9%). Three cohort studies were designed to compare the effect of the two drugs, whereas the others had other purposes. Levofloxacin was most frequently used among fluoroquinolones (187/331, 56.5%), followed by ciprofloxacin (114/331, 34.4%). The overall mortality rate was 29.6%. Using pooled ORs for the mortality of each study, fluoroquinolone treatment (OR 0.62, 95% CI 0.39-0.99) was associated with survival benefit over trimethoprim-sulfamethoxazole treatment, with low heterogeneity (I² = 18%). Specific fluoroquinolones such as ciprofloxacin (OR 0.44, 95% CI 0.17-1.12) and levofloxacin (OR 0.78, 95% CI 0.48-1.26) did not show a significant difference in comparison with trimethoprim-sulfamethoxazole. In the sub-group analyses of adult and bacteraemic patients, significant differences in mortality were not observed between fluoroquinolones and trimethoprim-sulfamethoxazole.

CONCLUSIONS

Based on a meta-analysis of non-randomized studies, fluoroquinolones demonstrated comparable effects on mortality of S. maltophilia infection to trimethoprim-sulfamethoxazole, supporting the use of fluoroquinolones in clinical S. maltophilia infections. Although the pooled analysis of overall studies favoured fluoroquinolones over trimethoprim-sulfamethoxazole, the studies included were observational, and sub-group analyses of certain fluoroquinolone agents did not show statistical differences with trimethoprim-sulfamethoxazole. Randomized clinical studies are needed to address these issues.