OUP accepted manuscript

Pharmacokinetics and pharmacological target attainment of standard temocillin dosing in non-critically ill patients with complicated urinary tract infections

OBJECTIVES

Temocillin, a carbapenem-sparing β-lactam antibiotic, is commonly used at the standard 4 g/day dosage for treating complicated urinary tract infections (cUTIs). However, pharmacokinetic/pharmacodynamic (PK/PD) data supporting this regimen is limited. This study evaluated the plasma pharmacokinetics (PK) and PTA of temocillin in non-critically ill cUTI patients with varying degrees of renal insufficiency (RI).

METHODS

In this single-centre clinical study, 22 cUTI patients received a fixed 4 g/day (2 g q12h, intravenously) temocillin dose, irrespective of renal function (no RI: n = 5, mild RI: n = 8, moderate RI: n = 9). Plasma samples were collected post-dosing for LC-MS analysis of total and unbound temocillin levels. Monte Carlo simulations were performed based on the established PK/PD target of ≥35% fT > MIC (minimal inhibitory concentration).

RESULTS

Among patients, the highest plasma drug exposure and PK/PD target attainment were observed in those with moderate RI (median AUC0-12h = 1143 h.mg/L and %fT > MIC = 68%), followed by mild RI patients (median AUC0-12h = 918 h.mg/L and %fT > MIC = 34%), and the lowest in those with healthy kidney function (median AUC0-12h = 692 h.mg/L and %fT > MIC = 26%). Simulations indicated that the 4 g/day temocillin dose achieves 90% PTA only for glomerular filtration rate < 60 mL/min and MIC ≤ 8 mg/L.

CONCLUSION

The standard temocillin dose may need to be increased from 4 to 6 g/day to treat non-critically ill cUTI patients, in line with recent EUCAST recommendations. For patients with moderate RI, who experience higher exposure due to reduced renal drug clearance, 4 g/day temocillin remains appropriate.

Review of the In Vitro Microbiological Activity of Mecillinam Against Common Uropathogens in Uncomplicated Urinary Tract Infection: Focus on Resistant Pathogens

Antimicrobial resistance in uropathogens commonly causing urinary tract infections (UTIs) is a growing problem internationally. Pivmecillinam, the oral prodrug of mecillinam, has been used for over 40 years, primarily in Northern Europe and Canada. It is recommended in several countries as a first-line agent for the treatment of uncomplicated UTIs (uUTIs) and is now approved in the United States. We performed a structured literature search to review the available evidence on susceptibility of common uUTI-causing uropathogens to mecillinam. Among 38 studies included in this literature review, susceptibility rates for Escherichia coli to mecillinam-including resistant phenotypes such as extended-spectrum β-lactamase-producing E. coli-exceed 90% in most studies. High rates of susceptibility were also reported among many other uropathogens including Klebsiella spp., Enterobacter spp., and Citrobacter spp. In the current prescribing climate within the United States, pivmecillinam represents a viable first-line treatment option for patients with uUTI.

Nitroxoline resistance is associated with significant fitness loss and diminishes in vivo virulence of Escherichia coli

IMPORTANCE

Antimicrobial resistance (AMR) poses a global threat and requires the exploration of underestimated treatment options. Nitroxoline, an effective broad-spectrum antibiotic, does not suffer from high resistance rates in the clinics but surprisingly, it is not heavily used yet. Our findings provide compelling evidence that Nitroxoline resistance renders bacteria unable to cause an infection in vivo, thereby reinvigorating the potential of Nitroxoline in combating AMR.

[Therapy of cystitis with nitroxoline-NitroxWin : Prospective, multicenter, non-interventional study and microbiological resistance surveillance]

BACKGROUND

According to German AWMF S3 guideline nitroxoline is recommended as one of the first-choice antibiotics for treatment of acute uncomplicated cystitis (UC) in women. Under real-world conditions the clinical efficacy of nitroxoline should be checked in a noninterventional, prospective and multicenter study (NIS) and the prevalence of nitroxoline resistance in E. coli be monitored.

MATERIALS AND METHODS

Female patients with UC treated with nitroxoline (recommended dosage 250 mg tid for 5 days) were included by urologists, general practitioners (GPs), and internists in family medicine throughout Germany from April-December 2022 and followed for 21-28 days. The diagnosis and course of therapy were judged by the Acute Cystitis Symptom Score (ACSS) questionnaire and laboratory investigations (leukocyturia etc). Separately, a nationwide resistance surveillance was performed during 2019-2020 in collaboration with 23 laboratories to collect urinary E. coli isolates and test their susceptibility to nitroxoline.

RESULTS

Of the 316 patients with mean (SD) age of 57.2 (±20.4 [median 62.5]) years who were included in the NIS, 193/248 (86.3%) in the per-protocol group and in 193/263 (81.44%) in the intention-to-treat group were clinically successful. Furthermore, 96% of the patients rated the tolerability of nitroxoline as "very good" or "good". All 272 E. coli isolates tested were susceptible to nitroxoline.

CONCLUSIONS

Nitroxoline showed very good clinical results in the NIS, and 100% of the tested E. coli urine isolates were susceptible to nitroxoline. Nitroxoline can still be recommended as one of the first-choice antibiotics for treatment of UC in women.

Antimicrobial resistance of clinical Enterobacterales isolates from urine samples, Germany, 2016 to 2021

IntroductionEmpirical therapy for the treatment of urinary tract infections should be tailored to the current distribution and susceptibility of potential pathogens to ensure optimal treatment.AimWe aimed to provide an up-to-date overview of the epidemiology and susceptibility of Enterobacterales isolated from urine in Germany.MethodsWe retrospectively analysed antimicrobial susceptibility data from 201,152 urine specimens collected between January 2016 and June 2021 from in- and outpatients. Multiple logistic regression analysis was used to evaluate the association between year of investigation and antibiotic resistance, adjusted for age, sex and species subgroup. Subgroup analyses were performed for midstream urine samples obtained from (i) female outpatients aged 15 to 50 years, (ii) female outpatients older than 50 years and (iii) male outpatients.ResultsResistance rates of less than 20% were observed for nitroxoline (3.9%), fosfomycin (4.6%), nitrofurantoin (11.7%), cefuroxime (13.5%) and ciprofloxacin (14.2%). Resistance to trimethoprim/sulfamethoxazole (SXT) (20.1%), amoxicillin-clavulanic acid (20.5%), trimethoprim (24.2%), pivmecillinam (29.9%) and ampicillin (53.7%) was considerably higher. In the subgroup of outpatient women aged 15-50 years, resistance rates were generally lower. Resistance rates of all antibiotics decreased from 2016 to 2021. Multiple logistic regression revealed the lowest adjusted odds ratio (ORadj) of 0.838 (95% confidence interval (CI): 0.819-0.858; p < 0.001) for pivmecillinam and the highest ORadj of 0.989 (95% CI: 0.972-1.007; p = 0.226) for nitrofurantoin.ConclusionsResistance has generally decreased over the past years, independent of sex, age and causative pathogen. Our data provide an important basis for empirical antibiotic recommendations in various settings and patient collectives.