Hyponatremia Associated With Standard-Dose Trimethoprim-Sulfamethoxazole Use in an Immunocompetent Patient.

INTRODUCTION: Trimethoprim-sulfamethoxazole (TMP-SMX) use in immunocompromised patients can cause dose-dependent electrolyte irregularities including hyponatremia, hyperkalemia, and metabolic acidosis. We report a case of isolated hyponatremia caused by low-dose TMP-SMX use in an immunocompetent patient that mimicked the syndrome of inappropriate antidiuretic hormone secretion (SIADH). CASE PRESENTATION: A 72-year-old woman was admitted to the hospital for acute onset of weakness and ambulatory dysfunction after starting TMP-SMX (160 mg/800 mg). She was found hyponatremic (sodium level, 125 mmol/L, down from 141 mmol/L prior to medication initiation). After ruling out diuretics use, and adrenal and thyroid dysfunction, we started her on intravenous saline infusion to manage her TMP-SMX-induced hyponatremia, and her symptoms resolved. DISCUSSION: Electrolyte problems in immunocompromised patients treated for opportunistic infections with high-dose TMP-SMX (≥ 8 mg/kg/d TMP) are well-documented. However, the effects in immunocompetent patients are uncommon when standard dose (< 8 mg/kg/d TMP) is used. CONCLUSIONS: TMP-SMX blocks the aldosterone-mediated sodium reabsorption in the collecting ducts, and the trimethoprim component itself is structurally similar to potassium-sparing diuretics, which block sodium uptake at the distal nephron-both of which can cause hyponatremia.

Population kinetic-pharmacodynamic analysis of serum potassium in patients receiving sulfamethoxazole/trimethoprim.

Since trimethoprim (TMP) dose-dependently inhibits the excretion of potassium, a population kinetic-pharmacodynamic analysis was performed to establish an adequate dosing schedule and characterize factors of hyperkalaemia. Dataset was constructed using a retrospective observational cohort of hospitalized patients (>18 years) with oral sulfamethoxazole/trimethoprim formulation. The model integrated a kinetic model for TMP, a urinary TMP concentration-response curve and a kinetic model for serum potassium using an indirect response model. The model was a function of body weight, renal function, serum potassium levels and TMP dosing schedule. We evaluated covariates by the stepwise forward and backward selection methods. The Monte Carlo simulation determined the probability of hyperkalaemia (>5.5 or >6.0 meq/L) according to the dosing schedule, renal function and covariates. This study included 317 patients [age 62 (42-72) years] with 4359 serum potassium levels. The significant covariate was non-steroidal anti-inflammatory drugs (NSAIDs), with a 72.3% reduction in 50% inhibitory concentration. Monte Carlo simulation revealed that high-dose TMP (400 mg thrice daily) co-administered with NSAIDs led to mild hyperkalaemia (>10%) and severe hyperkalaemia (approximately 5%), regardless of renal function. In conclusion, clinicians should pay attention to hyperkalaemia with TMP high-dose and co-administered NSAIDs.

Effect of high-dose sulfamethoxazole/trimethoprim and glucocorticoid use on hyperkalemic event: A retrospective observational study.

INTRODUCTION: Sulfamethoxazole/trimethoprim causes hyperkalemia; however, the effect of sulfamethoxazole/trimethoprim dose and co-administered glucocorticoids on hyperkalemia has not been clarified. METHODS: This single-center, retrospective, observational cohort, chart review study involving patients (>20 years) who were treated with sulfamethoxazole/trimethoprim was conducted at Tokyo Women's Medical University, Medical Center East from June 2015 to May 2019. Multivariate Cox proportional hazard model was used to identify risk factors for hyperkalemia (serum potassium level > 5.5 mEq/L). Additionally, Kaplan-Meier curve analyzed the cumulative incidence of hyperkalemia focusing on sulfamethoxazole/trimethoprim dose and concomitant use of glucocorticoids with mineralocorticoid activity. RESULTS: Among 333 patients, 44 (13%) patients developed hyperkalemia associated with sulfamethoxazole/trimethoprim use for over 49 (interquartile range; 17-233) days. We found associations between the time to hyperkalemia development and sulfamethoxazole/trimethoprim dose (hazard ratio 1.238, 95% confidence interval 1.147-1.338, p < 0.001) and glucocorticoid use (hazard ratio 0.678, 95% confidence interval 0.524-0.877, p = 0.003). Interestingly, the Kaplan-Meier curves revealed that the concomitant use of glucocorticoids did not attenuate the risk of hyperkalemia in patients receiving high-dose sulfamethoxazole/trimethoprim (p = 0.747), whereas concomitant use of glucocorticoids significantly reduced the risk of hyperkalemia in patients receiving non-high dose sulfamethoxazole/trimethoprim (p < 0.001). CONCLUSIONS: High-dose sulfamethoxazole/trimethoprim is a significant predictor of hyperkalemia. The effect of glucocorticoids on hyperkalemia varies depending on the sulfamethoxazole/trimethoprim dose.

Effect of 7 vs 14 Days of Antibiotic Therapy on Resolution of Symptoms Among Afebrile Men With Urinary Tract Infection: A Randomized Clinical Trial.

Importance: Determination of optimal treatment durations for common infectious diseases is an important strategy to preserve antibiotic effectiveness. Objective: To determine whether 7 days of treatment is noninferior to 14 days when using ciprofloxacin or trimethoprim/sulfamethoxazole to treat urinary tract infection (UTI) in afebrile men. Design, Setting, and Participants: Randomized, double-blind, placebo-controlled noninferiority trial of afebrile men with presumed symptomatic UTI treated with ciprofloxacin or trimethoprim/sulfamethoxazole at 2 US Veterans Affairs medical centers (enrollment, April 2014 through December 2019; final follow-up, January 28, 2020). Of 1058 eligible men, 272 were randomized. Interventions: Participants continued the antibiotic prescribed by their treating clinician for 7 days of treatment and were randomized to receive continued antibiotic therapy (n = 136) or placebo (n = 136) for days 8 to 14 of treatment. Main Outcomes and Measures: The prespecified primary outcome was resolution of UTI symptoms by 14 days after completion of active antibiotic treatment. A noninferiority margin of 10% was selected. The as-treated population (participants who took ≥26 of 28 doses and missed no more than 2 consecutive doses) was used for the primary analysis, and a secondary analysis included all patients as randomized, regardless of treatment adherence. Secondary outcomes included recurrence of UTI symptoms and/or adverse events within 28 days of stopping study medication. Results: Among 272 patients (median [interquartile range] age, 69 [62-73] years) who were randomized, 100% completed the trial and 254 (93.4%) were included in the primary as-treated analysis. Symptom resolution occurred in 122/131 (93.1%) participants in the 7-day group vs 111/123 (90.2%) in the 14-day group (difference, 2.9% [1-sided 97.5% CI, -5.2% to ∞]), meeting the noninferiority criterion. In the secondary as-randomized analysis, symptom resolution occurred in 125/136 (91.9%) participants in the 7-day group vs 123/136 (90.4%) in the 14-day group (difference, 1.5% [1-sided 97.5% CI, -5.8% to ∞]) Recurrence of UTI symptoms occurred in 13/131 (9.9%) participants in the 7-day group vs 15/123 (12.9%) in the 14-day group (difference, -3.0% [95% CI, -10.8% to 6.2%]; P = .70). Adverse events occurred in 28/136 (20.6%) participants in the 7-day group vs 33/136 (24.3%) in the 14-day group. Conclusions and Relevance: Among afebrile men with suspected UTI, treatment with ciprofloxacin or trimethoprim/sulfamethoxazole for 7 days was noninferior to 14 days of treatment with regard to resolution of UTI symptoms by 14 days after antibiotic therapy. The findings support the use of a 7-day course of ciprofloxacin or trimethoprim/sulfamethoxazole as an alternative to a 14-day course for treatment of afebrile men with UTI. Trial Registration: ClinicalTrials.gov identifier: NCT01994538.

Kidney stone formation and the gut microbiome are altered by antibiotics in genetic hypercalciuric stone-forming rats.

Antibiotics can alter the gut microbiome (GMB), which may be associated with stone disease. We sought to determine the effect that antibiotics have on the GMB, urine ion excretion and stone formation in genetic hypercalciuric stone-forming (GHS) rats. 116th generation GHS rats were fed a fixed amount of a normal calcium (1.2%) and phosphate (0.65%) diet, and divided into three groups (n = 10): control (CTL) diet, or supplemented with ciprofloxacin (Cipro, 5 mg/day) or Bactrim (250 mg/day). Urine and fecal pellets were collected over 6, 12 and 18 weeks. Fecal DNA was amplified across the 16S rRNA V4 region. At 18 weeks, kidney stone formation was visualized by Faxitron and blindly assessed by three investigators. After 18 weeks, urine calcium and oxalate decreased with Bactrim compared to CTL and Cipro. Urine pH increased with Bactrim compared to CTL and Cipro. Urine citrate increased with Cipro compared to CTL and decreased by half with Bactrim. Calcification increased with Bactrim compared to CTL and Cipro. Increased microbial diversity correlated with decreased urinary oxalate in all animals (R = - 0.46, p = 0.006). A potential microbial network emerged as significantly associated with shifts in urinary pH. Bactrim and Cipro differentially altered the GMB of GHS rats. The Bactrim group experienced a decrease in urine calcium, increased CaP supersaturation and increased calcification. The GMB is likely a contributing factor to changes in urine chemistry, supersaturation and stone risk. Further investigation is required to fully understand the association between antibiotics, the GMB and kidney stone formation.

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.

Single-dose versus 3-day cotrimoxazole prophylaxis in transurethral resection or greenlight laser vaporisation of the prostate: study protocol for a multicentre randomised placebo controlled non-inferiority trial (CITrUS trial).

BACKGROUND: Transurethral resection of the prostate (TURP) and Greenlight laser vaporisation (GL) of the prostate are frequently performed urological procedures. For TURP, a single-dose antimicrobial prophylaxis (AP) is recommended to reduce postoperative urinary tract infections. So far, no international recommendations for AP have been established for GL. In a survey-based study in Switzerland, Germany and Austria, urologists reported routinely extending AP primarily for 3 days after both interventions. We therefore aim to determine whether single-dose AP with cotrimoxazole is non-inferior to 3-day AP with cotrimoxazole in patients undergoing TURP or GL of the prostate. METHODS/DESIGN: We will conduct an investigator-initiated, multicentre, randomised controlled trial. We plan to assess the non-inferiority of single-dose AP compared to 3-day AP. The primary outcome is the occurrence of clinically diagnosed symptomatic urinary tract infections which are treated with antimicrobial agents within 30 days after randomisation. The vast majority of collected outcomes will be assessed from routinely collected data. The sample size was estimated to be able to show the non-inferiority of single-dose AP compared to 3-day AP with at least 80% power (1 - ß = 0.8) at a significance level of α = 5%, applying a 1:1 randomisation scheme. The non-inferiority margin was determined in order to preserve 70% of the effect of usual care on the primary outcome. For an assumed event rate of 9% in both treatment arms, this resulted in a non-inferiority margin of 4.4% (i.e. 13.4% to 9%). To prove non-inferiority, a total of 1574 patients should be recruited, in order to have 1416 evaluable patients. The study is supported by the Swiss National Science Foundation. DISCUSSION: For AP in TURP and GL, there is a large gap between usual clinical practice and evidence-based guidelines. If single-dose AP proves non-inferior to prolonged AP, our study findings may help to reduce the duration of AP in daily routine-potentially reducing the risk of emerging resistance and complications related to AP. TRIAL REGISTRATION: Clinicaltrials.gov, NCT03633643 . Registered 16 August 2018.

Prophylactic antibiotic therapy for chronic obstructive pulmonary disease (COPD).

BACKGROUND: There has been renewal of interest in the use of prophylactic antibiotics to reduce the frequency of exacerbations and improve quality of life in chronic obstructive pulmonary disease (COPD). OBJECTIVES: To determine whether or not regular (continuous, intermittent or pulsed) treatment of COPD patients with prophylactic antibiotics reduces exacerbations or affects quality of life. SEARCH METHODS: We searched the Cochrane Airways Group Trials Register and bibliographies of relevant studies. The latest literature search was performed on 27 July 2018. SELECTION CRITERIA: Randomised controlled trials (RCTs) that compared prophylactic antibiotics with placebo in patients with COPD. DATA COLLECTION AND ANALYSIS: We used the standard Cochrane methods. Two independent review authors selected studies for inclusion, extracted data, and assessed risk of bias. We resolved discrepancies by involving a third review author. MAIN RESULTS: We included 14 studies involving 3932 participants in this review. We identified two further studies meeting inclusion criteria but both were terminated early without providing results. All studies were published between 2001 and 2015. Nine studies were of continuous macrolide antibiotics, two studies were of intermittent antibiotic prophylaxis (three times per week) and two were of pulsed antibiotic regimens (e.g. five days every eight weeks). The final study included one continuous, one intermittent and one pulsed arm. The antibiotics investigated were azithromycin, erythromycin, clarithromycin, doxycyline, roxithromycin and moxifloxacin. The study duration varied from three months to 36 months and all used intention-to-treat analysis. Most of the pooled results were of moderate quality. The risk of bias of the included studies was generally low.The studies recruited participants with a mean age between 65 and 72 years and mostly at least moderate-severity COPD. Five studies only included participants with frequent exacerbations and two studies recruited participants requiring systemic steroids or antibiotics or both, or who were at the end stage of their disease and required oxygen. One study recruited participants with pulmonary hypertension secondary to COPD and a further study was specifically designed to asses whether eradication of Chlamydia pneumoniae reduced exacerbation rates.The co-primary outcomes for this review were the number of exacerbations and quality of life.With use of prophylactic antibiotics, the number of participants experiencing one or more exacerbations was reduced (odds ratio (OR) 0.57, 95% CI 0.42 to 0.78; participants = 2716; studies = 8; moderate-quality evidence). This represented a reduction from 61% of participants in the control group compared to 47% in the treatment group (95% CI 39% to 55%). The number needed to treat for an additional beneficial outcome with prophylactic antibiotics given for three to 12 months to prevent one person from experiencing an exacerbation (NNTB) was 8 (95% CI 5 to 17). The test for subgroup difference suggested that continuous and intermittent antibiotics may be more effective than pulsed antibiotics (P = 0.02, I² = 73.3%).The frequency of exacerbations per patient per year was also reduced with prophylactic antibiotic treatment (rate ratio 0.67; 95% CI 0.54 to 0.83; participants = 1384; studies = 5; moderate-quality evidence). Although we were unable to pool the result, six of the seven studies reporting time to first exacerbation identified an increase (i.e. benefit) with antibiotics, which was reported as statistically significant in four studies.There was a statistically significant improvement in quality of life as measured by the St George's Respiratory Questionnaire (SGRQ) with prophylactic antibiotic treatment, but this was smaller than the four unit improvement that is regarded as being clinically significant (mean difference (MD) -1.94, 95% CI -3.13 to -0.75; participants = 2237; studies = 7, high-quality evidence).Prophylactic antibiotics showed no significant effect on the secondary outcomes of frequency of hospital admissions, change in forced expiratory volume in one second (FEV1), serious adverse events or all-cause mortality (moderate-quality evidence). There was some evidence of benefit in exercise tolerance, but this was driven by a single study of lower methodological quality.The adverse events that were recorded varied among the studies depending on the antibiotics used. Azithromycin was associated with significant hearing loss in the treatment group, which was in many cases reversible or partially reversible. The moxifloxacin pulsed study reported a significantly higher number of adverse events in the treatment arm due to the marked increase in gastrointestinal adverse events (P < 0.001). Some adverse events that led to drug discontinuation, such as development of long QTc or tinnitus, were not significantly more frequent in the treatment group than the placebo group but pose important considerations in clinical practice.The development of antibiotic resistance in the community is of major concern. Six studies reported on this, but we were unable to combine results. One study found newly colonised participants to have higher rates of antibiotic resistance. Participants colonised with moxifloxacin-sensitive pseudomonas at initiation of therapy rapidly became resistant with the quinolone treatment. A further study with three active treatment arms found an increase in the degree of antibiotic resistance of isolates in all three arms after 13 weeks treatment. AUTHORS' CONCLUSIONS: Use of continuous and intermittent prophylactic antibiotics results in a clinically significant benefit in reducing exacerbations in COPD patients. All studies of continuous and intermittent antibiotics used macrolides, hence the noted benefit applies only to the use of macrolide antibiotics prescribed at least three times per week. The impact of pulsed antibiotics remains uncertain and requires further research.The studies in this review included mostly participants who were frequent exacerbators with at least moderate-severity COPD. There were also older individuals with a mean age over 65 years. The results of these studies apply only to the group of participants who were studied in these studies and may not be generalisable to other groups.Because of concerns about antibiotic resistance and specific adverse effects, consideration of prophylactic antibiotic use should be mindful of the balance between benefits to individual patients and the potential harms to society created by antibiotic overuse. Monitoring of significant side effects including hearing loss, tinnitus, and long QTc in the community in this elderly patient group may require extra health resources.

A Seven-Day Course of TMP-SMX May Be as Effective as a Seven-Day Course of Ciprofloxacin for the Treatment of Pyelonephritis.

BACKGROUND: The Infectious Diseases Society of America guidelines recommend either 14 days of trimethoprim-sulfamethoxazole (TMP-SMX) or 7 days of ciprofloxacin for the treatment of pyelonephritis. Antibiotic courses of 7 days of TMP-SMX vs 7 days of ciprofloxacin for pyelonephritis have not been previously compared. We evaluated the odds of a subsequent, symptomatic urinary tract infection (UTI) for women with Escherichia coli pyelonephritis receiving a 7-day course of TMP-SMX vs a 7-day course of ciprofloxacin. METHODS: Women ages 16 years and older with E. coli pyelonephritis presenting to 5 health care facilities in the greater Maryland area between 2010 and 2016 receiving either TMP-SMX or ciprofloxacin were included. Patients were excluded if they met any of the following criteria: (a) pregnancy, (b) dialysis dependency, (c) E. coli not susceptible to the treatment prescribed, (d) polymicrobial urine culture, or (e) >48 hours of antibiotic therapy other than TMP-SMX or ciprofloxacin. RESULTS: Of 272 women meeting eligibility criteria, 81 (30%) and 191 (70%) received 7 days of TMP-SMX and 7 days of ciprofloxacin, respectively. In an adjusted model, the likelihood of a recurrent UTI within 30 days for the TMP-SMX and ciprofloxacin groups was similar (adjusted odds ratio 2.30; 95% confidence interval, 0.72-7.42). CONCLUSIONS: Our findings suggest that 7 days of TMP-SMX therapy may result in similar clinical outcomes compared with 7 days of ciprofloxacin for the treatment of pyelonephritis. Considering the frequency of pyelonephritis and risks of antibiotic resistance and associated toxicities, decreasing the duration of antibiotic therapy for pyelonephritis may impact a large number of women.

Old antibiotics for multidrug-resistant pathogens: from in vitro activity to clinical outcomes.

Antimicrobial resistance is a major and emerging threat worldwide. New antimicrobials have been unable to meet the resistance challenge, and treatment options are limited for a growing number of resistant pathogens. More and more clinicians are relying on older antimicrobials for the treatment of multidrug-resistant (MDR) bacteria. Some older antimicrobials have maintained excellent in vitro activity against highly resistant pathogens. In some instances, use of older agents is limited by unfavourable pharmacokinetic/pharmacodynamic characteristics and/or toxicities. In general, clinical data pertaining to the use of older agents for the treatment of MDR pathogens are scarce. Research efforts should be focused on the evaluation of older agents for the treatment of MDR pathogens as well as evaluating how these agents perform in complex patient populations with various and multiple co-morbid conditions.

Trimethoprim/sulfamethoxazole versus vancomycin in the treatment of healthcare/ventilator-associated MRSA pneumonia: a case-control study.

Objectives: Therapeutic options available to treat MRSA pneumonia are limited. Trimethoprim/sulfamethoxazole is an attractive treatment because of its bactericidal anti-MRSA activity, oral and parenteral formulations and good penetration to the lung tissue. We aimed to compare the efficacy and safety of trimethoprim/sulfamethoxazole with vancomycin in the treatment of healthcare/ventilator-associated MRSA pneumonia. Methods: We carried out a retrospective case-control study of all consecutive hospitalized adult patients diagnosed with MRSA pneumonia at Beilinson Hospital during 2010-15 and treated with either vancomycin or trimethoprim/sulfamethoxazole. The primary outcomes were all-cause mortality at 30 days and clinical failure at the end of treatment. In order to reduce bias affecting the decision to use a specific antibiotic and as a sensitivity analysis, a propensity-score model for choosing between vancomycin and trimethoprim/sulfamethoxazole was used. Results: We identified 42 patients with MRSA pneumonia treated with trimethoprim/sulfamethoxazole and 39 treated with vancomycin. There were no significant differences in the baseline characteristics between the groups. Vancomycin-treated patients showed significantly higher 30 day mortality on both multivariate analysis (HR = 5.28; 95% CI = 1.50-18.60; P < 0.05) and sensitivity analysis with propensity score [vancomycin 13/24 (54.1%) versus trimethoprim/sulfamethoxazole 4/24 (16.7%); P < 0.05], and higher clinical failure rates [vancomycin 23/39 (59%) versus trimethoprim/sulfamethoxazole 15/42 (35.7%); P < 0.05], also in the sensitivity analysis with propensity score [vancomycin 14/24 (58.3%) versus trimethoprim/sulfamethoxazole 6/24 (25%); P < 0.05]. The rates of side effects in both arms were comparable. Conclusions: Trimethoprim/sulfamethoxazole appears to be superior to vancomycin in the treatment of MRSA pneumonia. A large-scale randomized controlled trial is needed to evaluate these findings.

Incidence of Hyponatremia with High-Dose Trimethoprim-Sulfamethoxazole Exposure.

BACKGROUND: Trimethoprim-sulfamethoxazole (TMP-SMX) is a commonly prescribed antibiotic used at high doses for treatment of pneumocystis pneumonia and other infections. Trimethoprim is structurally related to the potassium-sparing diuretic amiloride and has been associated with hyperkalemia and hyponatremia through blocking of epithelial sodium channels in the distal nephron. The incidence of hyponatremia in hospitalized patients treated with high-dose TMP-SMX is unknown. METHODS: We performed a single-center retrospective chart review of all hospitalized patients who received high-dose TMP-SMX (n = 235) from January 2012 to July 2014. Patients with congestive heart failure, cirrhosis, estimated glomerular filtration rate <30 mL/min/1.73 m2, baseline hyponatremia, and those on other medications associated with hyponatremia were excluded. Hyponatremia was defined as a serum sodium level <136 mEq/L. RESULTS: Analysis was restricted to 76 unique patients who received more than 8 mg/kg/d of TMP for ≥3 days. Mean starting serum sodium at time of TMP-SMX initiation was 138.4 ± 2.1 mEq/L. Fifty-five patients (72.3%) developed hyponatremia while on therapy, of which 43.6% (n = 24) were cases of serum sodium <130 mEq/L. Mean sodium at the time of nadir was 131.6 ± 5.1 mEq/L. Hyponatremia was noted, on average, 5.5 days after initiation of therapy, with more severe hyponatremia development among African American patients. Urine sodium concentrations were available for 40.0% (22/55) of incident hyponatremia cases, with mean urinary sodium of 104.8 ± 55.9 mEq/L. Hyponatremia often resolved within 3 weeks of drug discontinuation. CONCLUSIONS: There is a high incidence (72.3%) of hyponatremia associated with the use of high-dose TMP-SMX among hospitalized patients. This is an overlooked and potentially reversible cause of hyponatremia.

Impact of the combination of daptomycin and trimethoprim-sulfamethoxazole on clinical outcomes in methicillin-resistant Staphylococcus aureus infections.

Complicated Staphylococcus aureus infections, including bacteremia, are often associated with treatment failures, prolonged hospital stays, and the emergence of resistance to primary and even secondary therapies. Daptomycin is commonly used as salvage therapy after vancomycin failure for the treatment of methicillin-resistant S. aureus (MRSA) infections. Unfortunately, the emergence of daptomycin resistance, especially in deep-seated infections, has been reported, prompting the need for alternative or combination therapy. Numerous antibiotic combinations with daptomycin have been investigated clinically and in vitro. Of interest, the combination of daptomycin and trimethoprim-sulfamethoxazole (TMP-SMX) has proved to be rapidly bactericidal in vitro to strains that are both susceptible and nonsusceptible to daptomycin. However, to date, there is limited clinical evidence supporting the use of this combination. This was a multicenter, retrospective case series of patients treated with the combination of daptomycin and TMP-SMX for at least 72 h. The objective of this study was to describe the safety and effectiveness of this regimen in clinical practice. The most commonly stated reason that TMP-SMX was added to daptomycin was persistent bacteremia and/or progressive signs and symptoms of infection. After the initiation of combination therapy, the median time to clearance of bacteremia was 2.5 days. Microbiological eradication was demonstrated in 24 out of 28 patients, and in vitro synergy was demonstrated in 17 of the 17 recovered isolates. Further research with this combination is necessary to describe the optimal role and its impact on patient outcomes.

Treatment of brucellosis in a young child with trimethoprim/sulfamethoxazole anaphylaxis.

Brucellosis is a common zoonotic disease throughout the world. Brucella spp. transmit to humans through contact with fluids of infected animals, especially sheep, cattle, and goats. It is also transmitted by ingestion of fluid-derived products of infected animals, such as unpasteurized milk and cheese. Brucella spp. changes pH level of intracellular environment, so the first treatment approach is to administer antibiotics that have activity in acidic conditions. Anti-brucellosis treatment regimens include doxycycline for children older than eight years old and rifampicin and trimethoprim/sulfamethoxazole (TMP-SMX) combination therapy for children under eight years old, which may be able to act intracellularly under acidic conditions. A TMP-SMX allergy causing anaphylaxis has been reported previously. No alternative anti-brucellosis treatments have been reported in the literature for patients under eight years old with a TMP-SMX allergy. Here, we report a case of a child with brucellosis and a TMP-SMX allergy who was under eight years old at the time of diagnosis and was successfully treated with rifampicin, ciprofloxacin, and gentamicin.

Can levofloxacin be a useful alternative to trimethoprim-sulfamethoxazole for treating Stenotrophomonas maltophilia bacteremia?

A retrospective study was conducted to evaluate the efficacy of levofloxacin in the treatment of Stenotrophomonas maltophilia bacteremia. The 30-day mortality rates were similar between the trimerthoprim-sulfamethoxazole (TMP-SMX) and levofloxacin treatment groups. Adverse events related to antibiotics occurred more frequently in patients receiving TMP-SMX, and recurrent bacteremia due to levofloxacin-resistant S. maltophilia strains developed in patients treated with levofloxacin. Our data suggest that levofloxacin can be a useful alternative option for treating S. maltophilia infections.

An evaluation of hyperkalemia and serum creatinine elevation associated with different dosage levels of outpatient trimethoprim-sulfamethoxazole with and without concomitant medications.

BACKGROUND: Adverse events associated with high-dose trimethoprim-sulfamethoxazole (TMP-SMX) for outpatient infections, particularly those likely caused by community-acquired methicillin-resistant Staphylococcus aureus, have not been adequately characterized. OBJECTIVE: Describe hyperkalemia and acute renal injury associated with high-dose TMP-SMX. METHODS: An electronic medical record database retrospective study was conducted of outpatients receiving high-dose or low-dose TMP-SMX, comparing the incidences of hyperkalemia and acute renal injury. RESULTS: Of 6162 patients, more developed hyperkalemia (3.06% vs 1.05%, P < .0001) or acute renal injury (1.99% vs 0.700%, P = .0001) in the high-dose TMP-SMX group. Variables independently associated with hyperkalemia included age >58 years (odds ratio [OR] = 3.44; 95% CI = 1.86-7.0; P < .0001), concomitant receipt of an NSAID (OR = 1.71; 95% CI = 1.02-2.79; P = .044) or an ACE inhibitor (OR = 3.27; 95% CI = 2.06-5.14; P < .0001), high-dose TMP-SMX prescribed (OR = 2.92; 95% CI = 1.85-4.60; P < .0001), and baseline elevated serum creatinine (OR = 45.1; 95% CI = 21.7-93.2; P < .0001). Variables independently associated with acute renal injury included concomitant receipt of an ACE inhibitor (OR = 2.36; 95% CI = 1.01-5.24; P = .048) or a potassium supplement (OR = 4.10; 95% CI = 1.45-10.1; P = .010), high-dose TMP-SMX prescribed (OR = 3.70; 95% CI = 1.70-8.12; P = .0012), and baseline elevated serum creatinine (OR = 2110; 95% CI = 724-7980; P < .0001). CONCLUSIONS: Serum creatinine and potassium concentrations should be monitored in outpatients receiving high-dose TMP-SMX.

Urinary tract infection in male veterans: treatment patterns and outcomes.

BACKGROUND: Lengthier antimicrobial therapy is associated with increased costs, antimicrobial resistance, and adverse drug events. Therefore, establishing minimum effective antimicrobial treatment durations is an important public health goal. The optimal treatment duration and current treatment patterns for urinary tract infection (UTI) in men are unknown. We used Veterans Affairs administrative data to study male UTI treatment and outcomes. METHODS: Male UTI episodes in the Veterans Affairs system (fiscal year 2009) were identified by combining International Classification of Diseases, Ninth Revision codes with UTI-relevant antimicrobial prescriptions. Episodes were categorized as index, early recurrence (<30 days), or late recurrence (≥30 days) cases. Drug name, treatment duration, and outcomes (recurrence and Clostridium difficile infection during 12 months) were recorded for index cases. Demographic, clinical, and treatment characteristics were assessed for associations with outcomes in univariate and multivariate analyses. RESULTS: Among 4 854 765 outpatient male veterans, 39 149 UTI episodes involving 33 336 unique patients were identified, including 33 336 index cases (85.2%), 1772 early recurrences (4.5%), and 4041 late recurrences (10.3%). Highest-use antimicrobial agents were ciprofloxacin (62.7%) and trimethoprim-sulfamethoxazole (26.8%); 35.0% of patients received shorter-duration treatment (≤7 days), and 65.0% of patients received longer-duration treatment (>7 days). Of the index cases, 4.1% were followed by early recurrence and 9.9% by late recurrence. Longer-duration treatment was not associated with a reduction in early or late recurrence but was associated with increased late recurrence compared with shorter-duration treatment (10.8% vs 8.4%, P < .001), including in multivariate analysis (odds ratio, 1.20; 95% CI, 1.10-1.30). In addition, C difficile infection risk was significantly higher with longer-duration vs shorter-duration treatment (0.5% vs 0.3%, P = .02) and exhibited a similar suggestive trend in multivariate analysis (odds ratio, 1.42; 95% CI, 0.97-2.07). CONCLUSION: Longer-duration treatment (>7 days) for male UTI in the outpatient setting was associated with no reduction in early or late recurrence.

Evaluation of co-trimoxazole in the treatment of multidrug-resistant tuberculosis.

Co-trimoxazole (SXT), a combination of sulfamethoxazole and trimethoprim, has shown in vitro activity against Mycobacterium tuberculosis. However, the pharmacokinetic and pharmacodynamic parameters of SXT in multidrug-resistant (MDR) tuberculosis (TB) are, thus far, lacking. Therefore, we evaluated its pharmacokinetics and drug susceptibility, along with its tolerability during treatment. Based on drug susceptibility testing, MDR-TB patients received SXT as a part of their MDR treatment. The pharmacokinetic parameters of sulfamethoxazole, the effective component of SXT against M. tuberculosis, were evaluated. The ratio of the area under the curve from 0 to 24 h (AUC0-24) to minimum inhibitory concentration (MIC) was used as the best pharmacokinetic/pharmacodynamic parameter to predict the efficacy of sulfamethoxazole. Adverse effects of SXT were also evaluated. 10 patients with MDR-TB (one of whom had extensively drug-resistant TB) received 480 mg of SXT with a median dosage of 6.5 mg·kg(-1) of SXT (range 6.1-6.8 mg·kg(-1)) once daily for a median treatment period of 381 days (range 129-465 days). In two patients, the dose was escalated to 960 mg. The free AUC0-24/MIC of sulfamethoxazole exceeded 25 in only one patient. SXT was safe and well-tolerated, except for one patient who had gastrointestinal side-effects after receiving 960 mg of SXT. Additional studies are needed to find the pharmacokinetic and pharmacodynamic targets, and consequently to set the optimal dose, of SXT for MDR-TB treatment.

Maternofetal consequences of Coxiella burnetii infection in pregnancy: a case series of two outbreaks.

BACKGROUND: A high complication rate of Q fever in pregnancy is described on the basis of a limited number of cases. All pregnant women with proven Q fever regardless of clinical symptoms should therefore receive long-term cotrimoxazole therapy. But cotrimoxazole as a folic acid antagonist may cause harm to the fetus. We therefore investigated the Q fever outbreaks, Soest in 2003 and Jena in 2005, to determine the maternofetal consequences of Coxiella burnetii infection contracted during pregnancy. METHODS: Different outbreak investigation strategies were employed at the two sides. Antibody screening was performed with an indirect immunofluorescence test. Medical history and clinical data were obtained and serological follow up performed at delivery. Available placental tissue, amniotic fluid and colostrum/milk were further investigated by polymerase chain reaction and by culture. RESULTS: 11 pregnant women from Soest (screening rate: 49%) and 82 pregnant women from Jena (screening rate: 27%) participated in the outbreak investigation. 11 pregnant women with an acute C. burnetii infection were diagnosed. Three women had symptomatic disease. Three women, who were infected in the first trimester, were put on long-term therapy. The remaining women received cotrimoxazole to a lesser extent (n=3), were treated with macrolides for three weeks (n=1) or after delivery (n=1), were given no treatment at all (n=2) or received antibiotics ineffective for Q fever (n=1). One woman and her foetus died of an underlying disease not related to Q fever. One woman delivered prematurely (35th week) and one child was born with syndactyly. We found no obvious association between C. burnetii infection and negative pregnancy outcome. CONCLUSIONS: Our data do not support the general recommendation of long-term cotrimoxazole treatment for Q fever infection in pregnancy. Pregnant women with symptomatic C. burnetii infections and with chronic Q fever should be treated. The risk-benefit ratio of treatment in these patients, however, remains uncertain. If cotrimoxazole is administered, folinic acid has to be added.

Antibiotic exposure as a risk factor for fluconazole-resistant Candida bloodstream infection.

Recent exposure to azoles is an important risk factor for infection with fluconazole-resistant Candida spp., but little is known about the role of antibacterial drug exposure in the emergence of drug-resistant Candida. We did a prospective nationwide surveillance study of candidemia in Israel and analyzed the propensity score-adjusted association between antifungal and antibacterial drug exposure and bloodstream infection with C. glabrata and fluconazole-resistant Candida isolates. Four hundred forty-four episodes of candidemia (450 Candida isolates, 69 [15%] C. glabrata isolates, and 38 [8.5%] fluconazole-resistant isolates) from 18 medical centers in Israel were included. C. glabrata bloodstream infection was strongly associated with recent metronidazole exposure (odds ratio [OR], 3.2; P < 0.001). Infection with a fluconazole-resistant isolate was associated with exposure to carbapenems, trimethoprim-sulfamethoxazole, clindamycin, and colistin (odds ratio, 2.8; P = 0.01). The inclusion of antibacterial drug exposure in a multivariable model significantly enhanced the model's predictive accuracy for fluconazole-resistant Candida bloodstream infection. Our findings may be relevant to the selection of empirical antifungal treatment and broaden the scope of antibiotic-associated collateral damage.