Optimal timing of oral fosfomycin administration for pre-prostate biopsy prophylaxis

A Sensitive Liquid Chromatography-Tandem Mass Spectrometry Method for Measuring Fosfomycin Concentrations in Human Prostatic Tissue

The aim of this study was to develop and validate a fast and sensitive bioanalytical method for the accurate quantification of fosfomycin concentrations in human prostatic tissue. The sample preparation method only required milligrams of tissue sample. Each sample was mixed with two times its weight of water and homogenized. A methanol solution that was three times the volume of the internal standard (fosfomycin-13C3) was added, followed by vortex mixing and centrifugation. After its extraction from the homogenized prostatic tissue, fosfomycin was quantified by means of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) triple quadrupole system operating in negative electrospray ionization and multiple reaction monitoring detection mode. The analytical procedure was successfully validated in terms of specificity, sensitivity, linearity, precision, accuracy, matrix effect, extraction recovery, limit of quantification, and stability, according to EMA guidelines. The validation results, relative to three QC levels, were 9.9% for both the within-day and inter-day accuracy (BIAS%); 9.8% for within-day precision; and 9.9 for between-day precision. A marked matrix effect was observed in the measurements but was corrected by normalization with the internal standard. The average total recovery was high (approximatively 97% at the three control levels). The dynamic range of the method was 0.1-20 μg/g (R2 of 0.999). Negligible carry-over was observed after the injection of highly concentrated samples. F in the sample homogenate extracts was stable at 10 °C and 4 °C for at least 24 h. In the tissue sample freeze-thaw experiments, a significant decrease in F concentrations was observed after only two cycles from -80 °C to room temperature. The novel method was successfully applied to measure fosfomycin in prostatic tissue samples collected from 105 patients undergoing prostatectomy.

Efficacy of a Novel Prophylactic Scheme of Fosfomycin Trometamol in Patients Undergoing Endoscopic Surgery for Benign Prostatic Hyperplasia: Findings from a Prospective Monocentric Single-Arm Study

This study aimed to assess the efficacy of a novel prophylactic scheme of fosfomycin trometamol in patients undergoing elective HoLEP (holmium laser enucleation of the prostate) or TURP (transurethral resection of the prostate) procedures for treating benign prostatic hyperplasia. Patients affected by benign prostatic hyperplasia and undergoing elective HoLEP or TURP procedures during the period February 2022-June 2023 were prospectively enrolled. Two 3 g oral fosfomycin trometamol doses 12 h apart were administered at 8.00 p.m. on day -1 (i.e., the day before HoLEP or TURP procedure) and at 8.00 a.m. on day 0 (i.e., the day of the surgical procedure). The following outcomes were assessed: prevalence of fever occurring in the first 48 h after surgical procedure; prevalence of urological complications occurring after the surgical procedure; prevalence of proven urinary tract infections (UTIs) and/or bloodstream infections (BSIs) at 14 days post-procedure; and prevalence of emergency department admission for UTI-related sepsis at 14 days post-procedure. Univariate analysis comparing patients with and without proven UTI, BSI, or emergency department admission at 14 days post-procedure was carried out. Overall, 96 patients (median age 70 years) undergoing HoLEP (82.3%) or TURP (17.7%) were prospectively included. Median (IQR) time of surgical procedure after the morning fosfomycin dose was 226.5 min (range 88.5-393.75 min). Fever in the post-surgical 48 h occurred in 3/96 patients (3.1%). Prevalence of proven UTI at 14 days was as low as 1.0% (1/96), whereas no patient had proven BSI or UTI-related sepsis requiring emergency department admission at 14 days. Our findings support the contention that a prophylactic scheme based on two doses of fosfomycin trometamol 12 h apart before surgical intervention may represent a valuable strategy for preventing infectious complications in urologic patients undergoing HoLEP or TURP. Larger definitive confirmatory studies are warranted.

Fosfomycin Trometamol for the Prevention of Infectious Complications After Prostate Biopsy: A Consensus Statement by an International Multidisciplinary Group

CONTEXT

Transrectal ultrasound-guided prostate biopsy (TRPB) has been a standard of care for diagnosing prostate cancer but is associated with a high incidence of infectious complications.

OBJECTIVE

To achieve an expert consensus on whether fosfomycin trometamol provides adequate prophylaxis in TRPB and discuss its role as prophylaxis in transperineal prostate biopsy (TPPB).

EVIDENCE ACQUISITION

An international multidisciplinary group of experts convened remotely to discuss how to best use fosfomycin in various clinical settings and patient situations. Six statements related to prostate biopsy and the role of fosfomycin were developed, based on literature searches and relevant clinical experience.

EVIDENCE SYNTHESIS

Consensus was reached for all six statements. The group of experts was unanimous regarding fosfomycin as a preferred candidate for antimicrobial prophylaxis in TRPB. Fosfomycin potentially also meets the requirements for empiric prophylaxis in TPPB, although further clinical studies are needed to confirm or refute its utility in this setting. There is a risk of bias due to sponsorship by a pharmaceutical company.

CONCLUSIONS

Antimicrobial prophylaxis is mandatory in TRPB, and fosfomycin trometamol is an appropriate candidate due to low rates of resistance, a good safety profile, sufficient prostate concentrations, and demonstrated efficacy in reducing the risk of infectious complications following TRPB.

PATIENT SUMMARY

Patients undergoing transrectal ultrasound-guided prostate biopsy (TRPB) have a high risk of infectious complications, and antimicrobial prophylaxis is mandatory. However, increasing antimicrobial resistance, as well as safety concerns with fluoroquinolones, has restricted the number of antimicrobial options. Fosfomycin trometamol meets the requirements for a preferred antimicrobial in the prophylaxis of TRPB.

Efficacy and Safety of Oral Fosfomycin-Trometamol in Male Urinary Tract Infections with Multidrug-Resistant Enterobacterales

Background: Antimicrobial drugs to treat male urinary tract infection (UTI) with multidrug-resistant Enterobacterales are limited. We studied oral fosfomycin-trometamol (FT) in this situation. The objective was to assess the clinical cure rate in patients presenting UTIs treated with oral FT. Methods: We conducted a single-center observational retrospective study from January 2017 to August 2018. The primary endpoint was clinical cure; and the secondary endpoints were incidence of recurrences, oral FT safety, and microbiological cure. Results: Sixteen male patients were included, presenting 21 UTI episodes. Fourteen patients (88%) have at least one underlying urologic disorder. We described 4 episodes of acute UTI and 17 episodes of chronic bacterial prostatitis (CBP). Sixteen out of twenty-one Enterobacterales were extended spectrum beta-lactamase (ESBL)-producers and all the patients presented a resistance to fluoroquinolones and trimethoprim/sulfamethoxazole. In acute UTI, the regimen was a daily dose of oral FT for a mean duration of 2.5 weeks (+/−7.0 days). Clinical and microbiological recovery was achieved in all patients, with no recurrence after 5.3 months follow-up on average (+/−10.4 days). In CBP, the regimen was one oral dose of fosfomycin every 24–48 h, for a mean duration of 5.5 weeks/UTI episodes (+/−15.3 days). Clinical and microbiological recovery was found in 16/17 cases. Seven of the twelve patients with CBP had relapsed and 3/12 had had a new episode of infection after an average follow-up of 5.8 months. Only 6/21 of patients presented minor or moderate adverse effects, such as digestive disorders. Conclusions: FT could be an alternative option to carbapenems in the treatment of multidrug-resistant Enterobacterales infections for male UTIs.

[Antibiotic prophylaxis for transrectal prostate biopsy : In the context of restricted indications for fluoroquinolones and antibiotic stewardship]

Hintergrund

Die transrektale Prostatastanzbiopsie (TRPB) gehört zu den häufigsten interventionell-urologischen Eingriffen in Deutschland. Es wird leitliniengerecht eine kurzeitige periprozedurale Antibiotikaprophylaxe (PAP) empfohlen. Die Indikationsrücknahme von Fluorchinolonen als PAP-Substanz durch das Bundesinstitut für Arzneimittel und Medizinprodukte macht die Verwendung alternativer Substanzen notwendig.

Ziele

Im Rahmen der Studie wurde die klinische Praxis der PAP bei TRPB mit Fokus auf infektiöse Komplikationen im Vergleich zwischen Fluorchinolon- und Cotrimoxazol-PAP evaluiert.

Methodik

Es handelt sich um eine retrospektive monozentrische Auswertung klinischer Routinedaten von Patienten mit TRPB zwischen 03.01.2019 und 28.01.2021.

Ergebnisse

Es wurden 508 erwachsene männliche Patienten eingeschlossen, das mediane Alter betrug 68 Jahre. 55,9 % erhielten eine Cotrimoxazol-PAP, 40,0 % eine Fluorchinolon-PAP. Insgesamt traten in 5,5 % postinterventionelle Komplikationen auf, davon 50,0 % infektiöse Komplikationen. Der Vergleich von Cotrimoxazol- und Fluorchinolon-PAP ergab keinen Unterschied der Komplikationsraten. Bei aufgrund von Komplikationen durchgeführten mikrobiologischen Urinuntersuchungen zeigten sich Erregernachweise mit Resistenz gegenüber der zuvor eingesetzten PAP im Sinne einer Selektion.

Schlussfolgerung

Eine Cotrimoxazol-PAP für TRPB ist verglichen mit dem bisherigen Standard einer Fluorchinolon-PAP nicht mit vermehrt infektiösen Komplikationen assoziiert. Die präinterventionelle Analyse von Keimspektrum und Resistenz ermöglicht den Einsatz einer gezielten Prophylaxe und kann somit Komplikationen reduzieren.

Optimizing Aminoglycoside Dosing Regimens for Critically Ill Pediatric Patients with Augmented Renal Clearance: a Convergence of Parametric and Nonparametric Population Approaches

Augmented renal clearance (ARC) can occur in critically ill pediatric patients receiving aminoglycosides such as gentamicin and tobramycin, yet optimal dosing strategies for ARC are undefined. We evaluated the probability of achieving efficacious or toxic exposures in pediatrics. Parallel population modeling of concentration strategies were pursued using Pmetrics v1.5.2 (nonparametric) and Monolix v2019R2 (parametric). Bayesian exposures were used to classify ARC based on total clearance (CL). The effects of serum creatinine (SCR), creatinine clearance (CRCL), total body weight (TBW), postnatal age (PNA), and ARC were explored as covariates. The probabilities of target attainment (PTA) (i.e., maximum concentration [C _max]/MIC, area under the concentration-time curve [AUC]/MIC) and of toxic exposure (PTE) (i.e., minimum concentration [C _min] > 2 μg/ml) were calculated according to PNA and ARC. A total of 123 patients (1 to 21 years old, 56% female) contributed 304 concentrations. A two-compartment model was superior to a one-compartment model in both approaches. Bayesian posterior predicted concentrations from the nonparametric base model fit the data well (R ² = 0.96) and classified 34 patients as having ARC (28%). Both the nonparametric and parametric approaches resulted in allometrically scaling of TBW on volume (V) and clearance (CL). ARC modified CL and central V. CRCL and a maturation function modified CL. ARC was associated with a 1.49- versus 1.66-fold increase in CL and a 1.56- versus 1.66-fold increase in the central V (nonparametric versus parametric). A high dose of 12 mg/kg of body weight/day was required to achieve adequate PTA when MICs were 1 to 2 μg/ml; ARC lowered achievable MICs. When PNA was <2 years, PTE was increased. Aminoglycoside monotherapy should be avoided in critically ill pediatric patients with ARC when MICs exceed 1 μg/ml, as optimal exposures are unachievable with standard dosing.

Fosfomycin-trometamol (FT) or fluoroquinolone (FQ) as single-dose prophylaxis for transrectal ultrasound-guided prostate biopsy (TRUS-PB): A prospective cohort study

OBJECTIVES

The increasing incidence of fluoroquinolones (FQ) resistance may lower its efficacy in preventing UTI following transrectal ultrasound-guided prostate biopsy (TRUS-PB). We assessed the efficacy and safety of FQ and fosfomycin-trometamol (FT) in patients undergoing TRUS-PB.

METHODS

A prospective observational study was conducted between April 2017 and June 2019 and enrolled men undergoing TRUS-PB and receiving a single-dose of FQ (FQ-arm) or FT (FT-arm) for UTI prophylaxis per physician's choice. The primary efficacy endpoint was self-reported TRUS-PB UTI. We assessed baseline factors associated with UTI with logistic regression.

RESULTS

A total of 222 men were enrolled, 141/222 (64%) received FQ, and 81/222 (36%) FT. The median age was 67.6 years [IQR, 61.4-72.1] and the Charlson score was 3 [IQR, 3-5]. The overall incidence of self-reported TRUS-PB UTI was 12% (24/197, (95%CI, 8%-17%)): 15% (17/116, (95% CI, 10%-17%)) in FQ-arm, versus 9% (7/81, 95% CI (5%-13%)) in FT-arm (RR = 0.55 (95% CI, 0.22-1.40), p-value = 0.209). No baseline characteristic was significantly associated with TRUS-PB UTI. Safety was similar between the arms: the rate of the reported adverse event was 31% (36/116, (95% CI, 25%-37%) in the FQ-arm versus 36% (28/81, (95% CI, 28%-41%)) in the FT-arm (RR = 1.17 (95% CI, 0.64-2.15), p = 0.602).

CONCLUSIONS

TRUS-PB UTI prophylaxis with FT and FQ has similar efficacy and safety. A randomized comparison of these two antibiotics is warranted.

Pharmacokinetic Assessment of Pre- and Post-Oxygenator Vancomycin Concentrations in Extracorporeal Membrane Oxygenation: A Prospective Observational Study

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is a form of cardiopulmonary life support frequently utilized in catastrophic lung and or cardiac failure. Patients on ECMO often receive vancomycin therapy for treatment or prophylaxis against Gram-positive organisms. It is unclear if ECMO affects vancomycin pharmacokinetics, thus we modeled the pharmacokinetic behavior of vancomycin according to ECMO-specific variables.

METHODS

Adult patients receiving vancomycin and Veno-Arterial-ECMO between 12/1/2016 and 10/1/2017 were prospectively enrolled. Extracorporeal membrane oxygenation settings and four sets of pre- and post-oxygenator vancomycin concentrations were collected for each patient. Compartmental models were built and assessed ECMO flow rates on vancomycin clearance and potential circuit sequestration. Bayesian posterior concentrations of the pre- and post-oxygenator concentrations were obtained for each patient, and summary pharmacokinetic parameters were calculated. Simulations were performed from the final model for efficacy and toxicity predictions.

RESULTS

Eight patients contributed 64 serum concentrations. Patients were a median (interquartile range) age of 58.5 years (50.8-62.3) with a calculated creatinine clearance of 39 mL/min (29.5-62.5) and ECMO flow rates of 3980 mL/min (interquartile range = 3493.75-4132.5). A three-compartment model best fit the data (Bayesian: plasma pre-oxygenation R² = 0.99, post-oxygenation R² = 0.99). Vancomycin clearance was not impacted by ECMO flow rate (p = 0.7). Simulations demonstrated that vancomycin 1 g twice daily was rarely sufficient for minimum inhibitory concentrations > 0.5 mg/L. Doses ≥ 1.5 g twice daily often exceeded toxicity thresholds for exposure.

CONCLUSIONS

Extracorporeal membrane oxygenation flow rates did not influence vancomycin clearance between flow rates of 3500 and 5000 mL/min and vancomycin was not sequestered in ECMO. Common vancomycin regimens resulted in suboptimal efficacy and/or excessive toxicity. Individual therapeutic drug monitoring is recommended for patients on ECMO.

Pharmacological Interventions for Bacterial Prostatitis

Prostatitis is a common urinary tract condition but bring innumerable trouble to clinicians in treatment, as well as great financial burden to patients and the society. Bacterial prostatitis (acute bacterial prostatitis plus chronic bacterial prostatitis) accounting for approximately 20% among all prostatitis have made the urological clinics complain about the genital and urinary systems all over the world. The international challenges of antibacterial treatment (emergence of multidrug-resistant bacteria, extended-spectrum beta-lactamase-producing bacteria, bacterial biofilms production and the shift in bacterial etiology) and the transformation of therapeutic strategy for classic therapy have attracted worldwide attention. To the best of our knowledge currently, there is not a single comprehensive review, which can completely elaborate these important topics and the corresponding treatment strategy in an effective way. This review summarizes the general treatment choices for bacterial prostatitis also provides the alternative pharmacological therapies for those patients resistant or intolerant to general treatment.

Fosfomycin trometamol and N-acetyl-L-cysteine as combined oral therapy of difficult-to-treat chronic bacterial prostatitis: Results of a pilot study

This paper presents the results of a pilot study of difficult-to-treat patients (exhibiting several previous treatment failures or detection of extended-spectrum beta-lactamase [ESBL] strains) with chronic bacterial prostatitis (CBP) who underwent treatment with fosfomycin trometamol (FT) and N-acetyl-L-cysteine (NAC). Twenty-eight patients with clinically- and microbiologically-confirmed CBP who attended a single urological institution between January 2018 and March 2019 were treated with oral administration of 3 g FT once a day for 2 days, followed by a dose of 3 g every 48 h for 2 weeks, in combination with oral administration of NAC 600 mg once a day for 2 weeks. Clinical and microbiological analyses were carried out at the time of admission (T0) and during follow-up at 1 month (T1) and 6 months (T2) after the end of treatment. Symptoms were assessed by the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI) and International Prostatic Symptom Score (IPSS), and quality of life was assessed by Quality of Well-Being (QoL) questionnaires. Isolated strains were Escherichia coli (23 patients), Enterococcus spp. (3 patients), and Klebsiella oxytoca (2 patients). ESBL strain was found in 19 (67.8%) patients. Microbiological eradication was documented in 21 (75%) patients at the second follow-up visit and clinical cure was achieved in 20 (71.4%) patients. Significant changes on questionnaires were recorded between baseline and follow-up visits. Fifteen of 19 patients (78.9%) with ESBL strains were cured. No significant side effects were reported. FT in combination with NAC is a promising alternative therapy in difficult-to-treat CBP patients.

Turkish Urologists' preferences regarding antibiotic prophylaxis for transrectal prostate biopsy

OBJECTIVE

Antibiotic prophylaxis for transrectal prostate biopsy (PB) is very important in preventing infectious complications, and in this study, we aimed to evaluate the antibiotic preferences of Turkish urologist for transrectal PB.

MATERIAL AND METHODS

The survey about PB and antibiotic prophylaxis behaviors was administered to urologists working in Turkey who had previously participated in at least one international and one national congress.

RESULTS

A total of 237 urologists were included in the study. Antibiotic prophylaxis prior to PB was performed by 234 (98.7%) participants. Rectal swabbing prior to PB was not performed by 227 (95.8%) participants. The most common complication associated with PB was prostatitis (63%), followed by urinary tract infection (29%). Only 25.7% of Turkish urologists reported a single dose of antibiotic prophylaxis. Our participants often administered antibiotic prophylaxis for a period of 3, 5, or 7 days (16%, 21.1%, 35.9%, respectively). The most common antibiotic agent preferred for prophylaxis was ciprofloxacin (65%).

CONCLUSION

The biopsy behavior of Turkish urologists was mostly compatible with the literature, but it was revealed that Turkish urologists do not prefer single-dose antibiotic therapy, and their practice patterns regarding the administration of pre-biopsy rectal swabbing are inconsistent with the literature.

A pharmacokinetic-pharmacodynamic assessment of oral antibiotics for pyelonephritis

Antibiotic resistance to oral antibiotics recommended for pyelonephritis is increasing. The objective was to determine if there is a pharmacological basis to consider alternative treatments/novel dosing regimens for the oral treatment of pyelonephritis. A systematic review identified pharmacokinetic models of suitable quality for a selection of antibiotics with activity against Escherichia coli. MIC data was obtained for a population of E. coli isolates derived from patients with pyelonephritis. Pharmacokinetic/pharmacodynamic (PK/PD) simulations determined probability of target attainment (PTA) and cumulative fraction response (CFR) values for sub-populations of the E. coli population at varying doses. There are limited high-quality models available for the agents investigated. Pharmacokinetic models of sufficient quality for simulation were identified for amoxicillin, amoxicillin-clavulanic acid, cephalexin, ciprofloxacin, and fosfomycin trometamol. These antibiotics were predicted to have PTAs ≥ 0.85 at or below standard doses for the tested E. coli population including cephalexin 1500 mg 8 hourly for 22% of the population (MIC ≤ 4 mg/L) and ciprofloxacin 100 mg 12 hourly for 71% of the population (MIC ≤ 0.06 mg/L). For EUCAST-susceptible E. coli isolates, doses achieving CFRs ≥ 0.9 included amoxicillin 2500 mg 8 hourly, cephalexin 4000 mg 6 hourly, ciprofloxacin 200 mg 12 hourly, and 3000 mg of fosfomycin 24 hourly. Limitations in the PK data support carrying out additional PK studies in populations of interest. Oral antibiotics including amoxicillin, amoxicillin-clavulanic acid, and cephalexin have potential to be effective for a proportion of patients with pyelonephritis. Ciprofloxacin may be effective at lower doses than currently prescribed.

Nitrofurantoin and fosfomycin for resistant urinary tract infections: old drugs for emerging problems

Uncomplicated urinary tract infection is one of the most common indications for antibiotic use in the community However the Gram-negative organisms that can cause the infection are becoming more resistant to antibiotics

Many multidrug resistant organisms retain susceptibility to two old antibiotics nitrofurantoin and fosfomycin Advantages over newer drugs include their high urinary concentrations and minimal toxicity

Fosfomycin is a potential treatment option for patients with uncomplicated urinary tract infection due to resistant organisms Nitrofurantoin may be more effective and can be used for urinary infections in pregnant women

Effectiveness of fosfomycin tromethamine prophylaxis in preventing infection following transrectal ultrasound-guided prostate needle biopsy: Results from a large Canadian cohort

OBJECTIVES

Rates of infection following transrectal ultrasound-guided prostate biopsy (TRUSPB) are increasing. The aim of this study was to evaluate the effectiveness of fosfomycin tromethamine (FMT) prophylaxis in preventing post-TRUSPB infectious complications.

METHODS

This nested case-control study included patients undergoing TRUSPB in a Canadian tertiary-care hospital who developed post-TRUSPB bacteraemia or urinary tract infection. Four prophylaxis periods were defined: (i) ciprofloxacin, low-resistance period (CIPRO-LOW), 2002-2009; (ii) ciprofloxacin, high-resistance period (CIPRO-HIGH), 2010-October 2013; (iii) oral FMT, one dose (FOSFO1), December 2013-September 2015; and (iv) oral FMT, two doses (FOSFO2), November 2015-June 2016. Incidence rates of the infection were calculated.

RESULTS

TRUSPB (n=9391) resulted in 138 cases of urinary sepsis (58% with bacteraemia). The incidence rates were 1.8% (CIPRO-HIGH), 3.5% (FOSFO1; P=0.004 vs. CIPRO-HIGH) and 2.7% (FOSFO2; P=0.19 vs. CIPRO-HIGH). Although Escherichia coli remained the predominant pathogen with fosfomycin-based regimens, the proportion of infections caused by Klebsiella spp. was higher (20/66; 30.3%) than with ciprofloxacin-based regimens (2/77; 2.6%; P<0.0001).

CONCLUSION

Independent risk factors for infection were the prophylactic regimen administered, presence of urological co-morbidities and diabetes. FMT was therefore not an effective alternative to ciprofloxacin for preventing post-TRUSPB urinary sepsis. These results highlight the need for novel antibacterial prophylaxis approaches.

Performance Validation of Selective Screening Agars for Guiding Antimicrobial Prophylaxis in Patients Undergoing Prostate Biopsy

A rectal culture-guided antimicrobial prophylaxis strategy may prevent infections after transrectal ultrasound-guided prostate biopsy (TRUSP). The use of selective culture media could assist the choice of appropriate antibiotic prophylaxis. The objective of our study was to evaluate the performance of four selective media used for guidance of oral antibiotic prophylaxis in TRUSP. In this prospective validation study, we used MacConkey media with vancomycin plus one of the following antibiotics: ciprofloxacin (McC3+CIP/V), trimethoprim (McC3+TMP/V), fosfomycin (McC3+FOF/V), and amdinocillin-amoxicillin-clavulanic acid (McC3+MEC/V). First, clinical strains of Gram-negative bacilli (GNB) (n = 33) were evaluated for growth on the selective media. Thereafter, rectal swabs (n = 97) were randomly collected from residual material of fresh stool samples and plated on a growth control and the four selective media. Levels of recovery of GNB on the growth control and selective media were compared, and the MICs of the antibiotics used in this study were determined. The sensitivity and specificity of the four selective media amounted, respectively, to 90.0% (55.5 to 99.8%) and 98.7% (93.1 to 100.0%) for McC3+CIP/V, 95.7% (85.2 to 99.5%) and 100.0% (91.6 to 100.0%) for McC3+TMP/V, 95.5% (84.5 to 99.4%) and 97.8% (88.2 to 99.9%) for McC3+FOF/V, and 100.0% (76.8 to 100.0%) and 97.6% (87.4 to 99.9%) for McC3+MEC/V. In conclusion, the four selective media were sufficiently sensitive and specific for the identification of rectal GNB resistant to ciprofloxacin, trimethoprim, fosfomycin, or amdinocillin-amoxicillin-clavulanic acid. These media can have added value in streamlining the optimal culture based antibiotic prophylaxis in TRUSP in a non-labor-intensive manner.

Oral Fosfomycin for the Treatment of Acute and Chronic Bacterial Prostatitis Caused by Multidrug-Resistant Escherichia coli

Acute and chronic bacterial prostatitis in outpatients is commonly treated with oral fluoroquinolones; however, the worldwide dissemination of multidrug-resistant (MDR) Escherichia coli has resulted in therapeutic failures with fluoroquinolones. We reviewed the literature regarding the use of oral fosfomycin in the treatment of acute and chronic prostatitis caused by MDR E. coli. All English-language references on PubMed from 1986 to June 2017, inclusive, were reviewed from the search “fosfomycin prostatitis.” Fosfomycin demonstrates potent in vitro activity against a variety of antimicrobial-resistant E. coli genotypes/phenotypes including ciprofloxacin-resistant, trimethoprim-sulfamethoxazole-resistant, extended-spectrum β-lactamase- (ESBL-) producing, and MDR isolates. Fosfomycin attains therapeutic concentrations (≥4 μg/g) in uninflamed prostatic tissue and maintains a high prostate/plasma ratio up to 17 hours after oral administration. Oral fosfomycin's clinical cure rates in the treatment of bacterial prostatitis caused by antimicrobial-resistant E. coli ranged from 50 to 77% with microbiological eradication rates of >50%. An oral regimen of fosfomycin tromethamine of 3 g·q 24 h for one week followed by 3 g·q 48 h for a total treatment duration of 6–12 weeks appeared to be effective. Oral fosfomycin may represent an efficacious and safe treatment for acute and chronic prostatitis caused by MDR E. coli.

Comparison of fosfomycin against fluoroquinolones for transrectal prostate biopsy prophylaxis: an individual patient-data meta-analysis

PURPOSE

To systematically review and meta-analyse available evidence comparing fosfomycin trometamol (FT) to fluoroquinolone (FQ) prophylaxis to prevent transrectal ultrasound-guided prostate biopsy (TRUSPB) related infectious complications.

METHODS

Electronic databases were queried for studies comparing FT to FQ-based TRUSPB prophylaxis. Studies were assessed for comparable outcomes and methodological quality (ROBINS-I modification). The primary outcome measure was the relative odds of overall infectious complications following TRUSPB according to FT/FQ treatment, which was evaluated with meta-analysis. Safety and tolerability were also assessed. The relative odds of infections of different severity [Grade 1, bacteriuria and afebrile urinary tract infection (UTI); Grade 2, bacteraemia, febrile UTI, and urosepsis] according to FT/FQ treatment were also estimated.

RESULTS

Five studies, being three prospective randomised trials and two retrospective cohort studies, representing 3112 patients, were included. The relative odds of an infectious complication (OR 0.22, 95% CI 0.09-0.54) or of a more severe (Grade 2) infection (OR 0.13, 95% CI 0.07-0.26) were significantly lower in those receiving FT compared to FQ prophylaxis. A low incidence of medication-related side effects was observed. There were less observed infections due to FQ-resistant pathogens in those receiving FT prophylaxis.

CONCLUSIONS

Patients who received FT prophylaxis were less likely than those who received FQ prophylaxis to develop infections overall, as well as severe and resistant infections after TRUSPB. Assessing the performance of FT in other geographic locations or in comparison to targeted prophylaxis based on risk assessment or rectal cultures is desired.

Pharmacokinetics, Safety, and Tolerability of Single-Dose Intravenous (ZTI-01) and Oral Fosfomycin in Healthy Volunteers

The pharmacokinetics, safety, and tolerability of intravenous (i.v.) fosfomycin disodium (ZTI-01) and oral fosfomycin tromethamine were evaluated after a single dose in 28 healthy adult subjects. Subjects received a single 1-h i.v. infusion of 1 g and 8 g fosfomycin disodium and a single dose of 3 g oral fosfomycin tromethamine in a phase I, randomized, open-label, three-period crossover study. Serial blood and urine samples were collected before and up to 48 h after dosing. The mean pharmacokinetic parameters ± standard deviations of fosfomycin in plasma after 1 g and 8 g i.v., respectively, were the following: maximum clearance of drug in serum (C_max), 44.3 ± 7.6 and 370 ± 61.9 μg/ml; time to maximum concentration of drug in serum (T_max), 1.1 ± 0.05 and 1.08 ± 0.01 h; volume of distribution (V), 29.7 ± 5.7 and 31.5 ± 10.4 liters; clearance (CL), 8.7 ± 1.7 and 7.8 ± 1.4 liters/h; renal clearance (CL_R), 6.6 ± 1.9 and 6.3 ± 1.6 liters/h; area under the concentration-time curve from 0 to infinity (AUC_0-∞), 120 ± 28.5 and 1,060 ± 192 μg·h/ml; and half-life (t_1/2), 2.4 ± 0.4 and 2.8 ± 0.6 h. After oral administration, the parameters were the following: C_max, 26.8 ± 6.4 μg/ml; T_max, 2.25 ± 0.4 h; V/F, 204 ± 70.7 liters; CL/F, 17 ± 4.7 liters/h; CL_R, 6.5 ± 1.8 liters/h; AUC_0-∞, 191 ± 57.6 μg · h/ml; and t_1/2, 9.04 ± 4.5 h. The percent relative bioavailability of orally administered fosfomycin was 52.8% in relation to the 1-g i.v. dose. Approximately 74% and 80% of the 1-g and 8-g i.v. doses were excreted unchanged in the urine by 48 h compared to 37% after oral administration, with the majority of this excretion occurring by 12 h regardless of dosage form. No new safety concerns were identified during this study. The results of this study support further investigation of i.v. fosfomycin in the target patient population, including patients with complicated urinary tract infections and pyelonephritis.

Pharmacodynamic Evaluation of Fosfomycin against Escherichia coli and Klebsiella spp. from Urinary Tract Infections and the Influence of pH on Fosfomycin Activities

Fosfomycin is widely used for the treatment of uncomplicated urinary tract infection (UTI), and it has recently been recommended that fosfomycin be used to treat infections caused by multidrug-resistant (MDR) Gram-negative bacilli. Whether urine acidification can improve bacterial susceptibility to fosfomycin oral dosing regimens has not been analyzed. The MIC of fosfomycin for 245 Gram-negative bacterial isolates, consisting of 158 Escherichia coli isolates and 87 Klebsiella isolates which were collected from patients with urinary tract infections, were determined at pH 6.0 and 7.0 using the agar dilution method. Monte Carlo simulation of the urinary fosfomycin area under the concentration-time curve (AUC) after a single oral dose of 3,000 mg fosfomycin and the MIC distribution were used to determine the probability of target attainment (PTA). Fosfomycin was effective against E. coli (MIC₉₀ ≤ 16 μg/ml) but not against Klebsiella spp. (MIC₉₀ > 512 μg/ml). Acidification of the environment increased the susceptibility of 71% of the bacterial isolates and resulted in a statistically significant decrease in bacterial survival. The use of a regimen consisting of a single oral dose of fosfomycin against an E. coli isolate with an MIC of ≤64 mg/liter was able to achieve a PTA of ≥90% for a target pharmacodynamic index (AUC/MIC) of 23 in urine; PTA was not achieved when the MIC was higher than 64 mg/liter. The cumulative fractions of the bacterial responses (CFR) were 99% and 55% against E. coli and Klebsiella spp., respectively, based on simulated drug exposure in urine with an acidic pH of 6.0. A decrease of the pH from 7.0 to 6.0 improved the PTA and CFR of the target pharmacodynamic index in both E. coli and Klebsiella isolates.

Prostate Biopsy-related Infection: A Systematic Review of Risk Factors, Prevention Strategies, and Management Approaches

A systematic review to identify risk factors for prostate biopsy-related infection, preventative strategies, and optimal management of infectious complications was conducted. Significant risk factors for postbiopsy infection include urogenital infection, antibiotic use, international travel, hospital exposure, bacteriuria, previous transrectal biopsy, and resistance of fecal flora to antibiotic prophylaxis (especially fluoroquinolones). Patients at risk may benefit from an adjusted biopsy protocol comprising transrectal biopsy under targeted prophylaxis, and/or the use of rectal disinfection techniques or using a transperineal approach. Management of biopsy-related infection should be based on individual risk and local resistance profiles with input from multiple specialties.

Fosfomycin

The treatment of bacterial infections suffers from two major problems: spread of multidrug-resistant (MDR) or extensively drug-resistant (XDR) pathogens and lack of development of new antibiotics active against such MDR and XDR bacteria. As a result, physicians have turned to older antibiotics, such as polymyxins, tetracyclines, and aminoglycosides. Lately, due to development of resistance to these agents, fosfomycin has gained attention, as it has remained active against both Gram-positive and Gram-negative MDR and XDR bacteria. New data of higher quality have become available, and several issues were clarified further. In this review, we summarize the available fosfomycin data regarding pharmacokinetic and pharmacodynamic properties, the in vitro activity against susceptible and antibiotic-resistant bacteria, mechanisms of resistance and development of resistance during treatment, synergy and antagonism with other antibiotics, clinical effectiveness, and adverse events. Issues that need to be studied further are also discussed.

Evaluation of Vancomycin Exposures Associated with Elevations in Novel Urinary Biomarkers of Acute Kidney Injury in Vancomycin-Treated Rats

Vancomycin has been associated with acute kidney injury (AKI). However, the pharmacokinetic/toxicodynamic relationship for AKI is not well defined. Allometrically scaled vancomycin exposures were used to assess the relationship between vancomycin exposure and AKI. Male Sprague-Dawley rats received clinical-grade vancomycin in normal saline (NS) as intraperitoneal (i.p.) injections for 24- to 72-h durations with doses ranging 0 to 200 mg/kg of body weight divided once or twice daily. Urine was collected over the protocol's final 24 h. Renal histopathology was qualitatively scored. Urinary biomarkers (e.g., cystatin C, clusterin, kidney injury molecule 1 [KIM-1], osteopontin, lipocalin 2/neutrophil gelatinase-associated lipocalin 2) were assayed using a Luminex xMAP system. Plasma vancomycin concentrations were assayed by high-performance liquid chromatography with UV detection. A three-compartment vancomycin pharmacokinetic model was fit to the data with the Pmetrics package for R. The exposure-response in the first 24 h was evaluated using Spearman's nonparametric correlation coefficient (rs) values for the area under the concentration-time curve during the first 24 h (AUC0-24), the maximum concentration in plasma during the first 24 h (Cmax0-24 ), and the lowest (minimum) concentration in plasma after the dose closest to 24 h (Cmin0-24 ). A total of 52 rats received vancomycin (n = 42) or NS (n = 10). The strongest exposure-response correlations were observed between AUC0-24 and Cmax0-24 and urinary AKI biomarkers. Exposure-response correlations (rs values) for AUC0-24, Cmax0-24 , and Cmin0-24 were 0.37, 0.39, and 0.22, respectively, for clusterin; 0.42, 0.45, and 0.26, respectively, for KIM-1; and 0.52, 0.55, and 0.42, respectively, for osteopontin. However, no differences in histopathological scores were observed. Optimal sampling times after administration of the i.p. dose were 0.25, 0.75, 2.75, and 8 h for the once-daily dosing schemes and 0.25, 1.25, 14.5, and 17.25 h for the twice-daily dosing schemes. Our observations suggest that AUC0-24 or Cmax0-24 correlates with increases in urinary AKI biomarkers.

Antimicrobial prophylaxis for transrectal ultrasound-guided prostate biopsy: fosfomycin trometamol, an attractive alternative

OBJECTIVE

To compare fosfomycin trometamol (FT) and ciprofloxacin (CIP) for antibiotic prophylaxis in transrectal prostate biopsy (TR-PB).

PATIENTS AND METHODS

Data for 1109 patients (mean age 66.7 ± 8.45) who underwent TR-PB between March to September 2015 in seven Italian urological institutions were retrospectively reviewed, of which 632 received FT (Group 1) and 477 received CIP (Group 2) for prophylaxis. We reviewed all urine culture results obtained after the procedure, all adverse drug reactions (ADRs) related to the drug and all febrile and/or symptomatic urinary tract infections (UTIs) occurring within 1 month after TR-PB. The rate of symptomatic UTIs and the rate of ADRs were considered the main outcome measures.

RESULTS

In the total study population, 72/1109 (6.5 %) patients experienced symptomatic UTIs and among these 11 (0.9 % of total) had urosepsis. Out of 72, 53 (73.6 %) symptomatic UTIs were caused by fluoroquinolone-resistant strains. Out of 632, 10 (1.6 %) patients in Group 1 and 62/477 (12.9 %) patients in Group 2 had symptomatic UTIs (p < 0.001); in particular, 2/632 (0.3 %) patients in Group 1 and 9/477 (1.8 %) patients in Group 2 had urosepsis (p < 0.001). No differences were reported in terms of adverse events (0.6 vs 0.4 %; p = 0.70). A Charlson comorbidity index ≤1 and type of antimicrobial prophylaxis (FT) were found to be associated with a lower probability of symptomatic UTIs in the multivariate model.

CONCLUSIONS

Antibiotic prophylaxis with FT for TR-PB had a lower rate of adverse events and a lower rate of symptomatic UTIs as compared with CIP. Fosfomycin trometamol appears as an attractive alternative prophylactic regimen in prostate biopsies.

Pharmacokinetics of centhaquin citrate in a dog model

OBJECTIVES

Centhaquin citrate is a novel agent that is being developed for use in the resuscitation of patients with haemorrhagic shock. While pharmacokinetics have been described in small animal models, the pharmacokinetic parameters of centhaquin citrate in large mammals have yet to be described.

METHODS

Four healthy Beagle dogs (two males and two females) were given an intravenous bolus of 1.0 mg/kg centhaquin citrate. Plasma concentrations were measured at baseline and at ten time points within 24 h after administration. Multiple compartmental models were built and compared. The nonparametric adaptive grid function within the Pmetrics package for R was used for parameter estimation. Predicted concentrations were calculated using population mean and individual Bayesian posterior parameters.

KEY FINDINGS

Centhaquin citrate pharmacokinetic parameters were best described using a two-compartment model. Median (IQR) values for Ke , Vc , Vp , Kcp and Kpc were 4.9 (4.4-5.2) h(-1) , 328.4 (304.0-331.9) l, 1000.6 (912.3-1042.4) l, 10.6 (10.3-11.1) h(-1) and 3.2 (2.9-3.7) h(-1) , respectively.

CONCLUSIONS

Pharmacokinetic parameters of centhaquin citrate in a large mammal have been described. A large volume of distribution and rapid elimination were observed, consistent with previous work in rats.

Fosfomycin: Resurgence of an old companion

Fosfomycin was discovered over four decades ago, yet has drawn renewed interest as an agent active against a range of multidrug-resistant (MDR) and extensively drug-resistant (XDR) pathogens. Its unique mechanism of action and broad spectrum of activity makes it a promising candidate in the treatment of various MDR/XDR infections. There has been a surge of in vitro data on its activity against MDR/XDR organisms, both when used as a single agent and in combination with other agents. In the United States, fosfomycin is only approved in an oral formulation for the treatment of acute uncomplicated urinary tract infections (UTIs), whereas in some countries both oral and intravenous formulations are available for various indications. Fosfomycin has minimal interactions with other medications and has a relatively favorable safety profile, with diarrhea being the most common adverse reaction. Fosfomycin has low protein binding and is excreted primarily unchanged in the urine. The clinical outcomes of patients treated with fosfomycin are favorable for uncomplicated UTIs, but data are limited for use in other conditions. Fosfomycin maintains activity against most Enterobacteriaceae including Escherichia coli, but plasmid-mediated resistance due to inactivation have appeared in recent years, which has the potential to compromise its use in the future. In this review, we summarize the current knowledge of this resurgent agent and its role in our antimicrobial armamentarium.

Pharmacokinetics of centhaquin citrate in a rat model

OBJECTIVE

Centhaquin citrate is a novel agent being developed for use in the treatment of haemorrhagic shock. It has decreased mortality in rat, rabbit and pig models of hypovolaemic shock compared to hypertonic saline and lactated Ringer's resuscitation. The pharmacokinetics of centhaquin citrate have not been described to date.

METHODS

Sixteen male Sprague Dawley rats were given an intravenous bolus of 0.45 mg/kg centhaquin citrate. Rats were divided into two groups; plasma concentrations were measured at five time points for each group within 24 h after administration. Competing compartmental pharmacokinetic models were assessed. The nonparametric adaptive grid function within the Pmetrics package for R was used for parameter estimation. Predicted concentrations were calculated using population median and individual Bayesian posterior parameters.

KEY FINDINGS

A two-compartment model of centhaquin citrate best fit the data. Median (IQR) values for elimination coefficient (Ke), volume of distribution (V) and intercompartmental transfer rates (Kcp, Kpc) were 8.8 (5.2-12.8) h(-1), 6.4 (2.8-10.4) l, 11.9 (4.6-15.0) h(-1) and 3.7 (2.3-9.1) h(-1), respectively.

CONCLUSION

This is the first report of the pharmacokinetic parameters of centhaquin citrate in a rat model. Centhaquin citrate was found to have a short half-life with a large volume of distribution.

The emerging threat of multidrug-resistant Gram-negative bacteria in urology

Antibiotic resistance in Gram-negative uropathogens is a major global concern. Worldwide, the prevalence of Enterobacteriaceae that produce extended-spectrum β-lactamase or carbapenemase enzymes continues to increase at alarming rates. Likewise, resistance to other antimicrobial agents including aminoglycosides, sulphonamides and fluoroquinolones is also escalating rapidly. Bacterial resistance has major implications for urological practice, particularly in relation to catheter-associated urinary tract infections (UTIs) and infectious complications following transrectal-ultrasonography-guided biopsy of the prostate or urological surgery. Although some new drugs with activity against Gram-negative bacteria with highly resistant phenotypes will become available in the near future, the existence of a single agent with activity against the great diversity of resistance is unlikely. Responding to the challenges of Gram-negative resistance will require a multifaceted approach including considered use of current antimicrobial agents, improved diagnostics (including the rapid detection of resistance) and surveillance, better adherence to basic measures of infection prevention, development of new antibiotics and research into non-antibiotic treatment and preventive strategies.

Rapid Identification of Rectal Multidrug-resistant Escherichia coli Before Transrectal Prostate Biopsy

OBJECTIVE

To develop and evaluate a rapid multiplex-quantitative polymerase chain reaction (qPCR) to identify fecal carriers of multidrug-resistant extraintestinal pathogenic Escherichia coli (MDR-ExPEC) clonal groups.

METHODS

Men presenting for transrectal prostate biopsy (TPB) at the San Diego Veterans Affairs Medical Center underwent rectal culture immediately before TPB. Rectal swabs were streaked onto ciprofloxacin-supplemented (4 mg/L) MacConkey agar plates, identified, and susceptibility tested. The same swab was sent to the University of Washington for qPCR test (EST200) targeting 2 major MDR-ExPEC clonal groups--ST131 and ST69--that combined were expected to represent majority of fluoroquinolone (FQ)- and trimethoprim-sulfamethoxazole-resistant E coli. We calculate test characteristics including the area under the receiver operative curve (AUC).

RESULTS

We enrolled 104 men from 11/5/2013 to 6/10/2014. FQ-resistant E coli were cultured from 19.2% (20/104) of rectal swabs, and 26% (27/104) of all swabs were positive for EST200 by PCR. The test characteristics comparing the EST200 to the culture-based detection of FQ resistance were 75%, 86%, 94%, and 56%, respectively. The AUC was 0.84 for the EST200 to detect FQ resistance before TPB.

CONCLUSION

Compared to the reference standard rectal culture, EST200 was able to detect majority of FQ-resistant E coli on rectal swabs before prostate biopsy.

Fosfomycin for Treatment of Prostatitis: New Tricks for Old Dogs

Treatment options for prostatitis caused by multidrug-resistant gram-negative bacilli are limited. We report two cases cured with oral fosfomycin and provide a pharmacokinetic analysis of fosfomycin predose concentrations during treatment.