Treatment Failure Due to Adaptive Resistance Mechanisms in a Severe and Complicated Bloodstream Infection Due to Elizabethkingia meningoseptica.

Elizabethkingia meningoseptica is an uncommonly encountered multidrug-resistant gram-negative bacterium that causes infections primarily among vulnerable hosts. A true opportunistic pathogen, its ability to cause severe sepsis and complicated infection in selected patients has been noted. Very limited preclinical and clinical data exist with regard to suitable therapeutic options. In this study, we present the case of prolonged bloodstream and central nervous system infection due to E. meningoseptica treated with dose-optimized combination antibiotic therapy, with evidence of microbiological (including development of adaptive resistance mechanisms) and clinical failure.

Guideline of guidelines: management of recurrent urinary tract infections in women.

OBJECTIVE: To compare recurrent urinary tract infection (rUTI) guidelines from major urological and non-urological organisations internationally and identify areas of consensus and discrepancy. METHODS: PubMed, Google Scholar and the official webpages of major urological, gynaecological, infectious diseases and general practice organisations were searched for rUTI guidelines in March 2022. Nine guidelines were included for review: European Association of Urology, National Institute for Health and Care Excellence (NICE), Society of Obstetricians and Gynaecologists of Canada, American Academy of Family Physicians, Mexican College of Gynaecology and Obstetrics Specialists, Swiss Society of Gynaecology and Obstetrics, Spanish Society of Infectious Diseases and Clinical Microbiology, German Association of Scientific Medical Societies, and the combined American Urological Association/Canadian Urological Association/Society of Urodynamics, Female Pelvic Medicine and Urogenital Reconstruction. RESULTS: The definition and evaluation of rUTIs, and antibiotic prophylaxis strategies, were mostly consistent across guidelines, and emphasised the importance of obtaining urine cultures and limiting cystoscopy and upper tract imaging in women without risk factors. Variable recommendations were noted for symptomatic treatment, self-initiated antibiotics, and antibiotic-sparing preventative strategies such as cranberry, vaginal oestrogen, immunoactive prophylaxis with OM-89, intravesical glycosaminoglycan instillation, and phytotherapeutics. Recent randomised evidence supports the use of methenamine hippurate. Either continuous or post-coital prophylactic antibiotics were supported by all guidelines. None of the guidelines were tailored to the management recurrent complicated UTI. CONCLUSION: Multiple rUTI guidelines were identified and mostly limited their recommendations to otherwise healthy non-pregnant women with uncomplicated cystitis. Variation was noted, particularly in antibiotic-sparing preventative strategies. Some conflicting recommendations are due to more recent guidelines including updated evidence. Future guidelines should consider recommendations to assist management of complex patient groups, such as recurrent complicated UTI.

Investigator-Driven Randomised Controlled Trial of Cefiderocol versus Standard Therapy for Healthcare-Associated and Hospital-Acquired Gram-negative Bloodstream Infection: Study protocol (the GAME CHANGER trial): study protocol for an open-label, randomised controlled trial.

BACKGROUND: Increasing rates of antibiotic resistance in Gram-negative organisms due to the presence of extended-spectrum beta-lactamases (ESBL), hyperproduction of AmpC enzymes, carbapenemases and other mechanisms of resistance are identified in common hospital- and healthcare-associated pathogens including Enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter baumannii. Cefiderocol is a novel siderophore cephalosporin antibiotic with a catechol moiety on the 3-position side chain. Cefiderocol has been shown to be potent in vitro against a broad range of Gram-negative organisms, including carbapenem-resistant Enterobacteriaceae (CRE) and multi-drug-resistant (MDR) P. aeruginosa and A. baumannii. Recent clinical data has shown cefiderocol to be effective in the setting of complicated urinary tract infections and nosocomial pneumonia, but it has not yet been studied as treatment of bloodstream infection. METHODS: This study will use a multicentre, open-label non-inferiority trial design comparing cefiderocol and standard of care antibiotics. Eligible participants will be adult inpatients who are diagnosed with a bloodstream infection with a Gram-negative organism on the basis of a positive blood culture result where the acquisition meets the definition for healthcare-associated or hospital-acquired. It will compare cefiderocol with the current standard of care (SOC) antibiotic regimen according to the patient's treating clinician. Eligible participants will be randomised 1:1 to cefiderocol or SOC and receive 5-14 days of antibiotic therapy. Trial recruitment will occur in at least 20 sites in ten countries (Australia, Malaysia, Singapore, Thailand, Turkey and Greece). The sample size has been derived from an estimated 14 day, all-cause mortality rate of 10% in the control group, and a non-inferiority margin of 10% difference in the two groups. A minimum of 284 patients are required in total to achieve 80% power with a two-sided alpha level of 0.05. Data describing demographic information, risk factors, concomitant antibiotics, illness scores, microbiology, multidrug-resistant organism screening, discharge and mortality will be collected. DISCUSSION: With increasing antimicrobial resistance, there is a need for the development of new antibiotics with broad activity against Gram-negative pathogens such as cefiderocol. By selecting a population at risk for multi-drug-resistant pathogens and commencing study treatment early in the clinical illness (within 48 h of index blood culture) the trial hopes to provide guidance to clinicians of the efficacy of this novel agent. TRIAL REGISTRATION: The GAME CHANGER trial is registered under the US National Institute of Health ClinicalTrials.gov register, reference number NCT03869437 . Registered on March 11, 2019.

Ceftolozane-tazobactam versus meropenem for definitive treatment of bloodstream infection due to extended-spectrum beta-lactamase (ESBL) and AmpC-producing Enterobacterales ("MERINO-3"): study protocol for a multicentre, open-label randomised non-inferiority trial.

BACKGROUND: Extended-spectrum beta-lactamase (ESBL) and AmpC-producing Enterobacterales are common causes of bloodstream infection. ESBL-producing bacteria are typically resistant to third-generation cephalosporins and result in a sizeable economic and public health burden. AmpC-producing Enterobacterales may develop third-generation cephalosporin resistance through enzyme hyper-expression. In no observational study has the outcome of treatment of these infections been surpassed by carbapenems. Widespread use of carbapenems may drive the development of carbapenem-resistant Gram-negative bacilli. METHODS: This study will use a multicentre, parallel group open-label non-inferiority trial design comparing ceftolozane-tazobactam and meropenem in adult patients with bloodstream infection caused by ESBL or AmpC-producing Enterobacterales. Trial recruitment will occur in up to 40 sites in six countries (Australia, Singapore, Italy, Spain, Saudi Arabia and Lebanon). The sample size is determined by a predefined quantity of ceftolozane-tazobactam to be supplied by Merck, Sharpe and Dohme (MSD). We anticipate that a trial with 600 patients contributing to the primary outcome analysis would have 80% power to declare non-inferiority with a 5% non-inferiority margin, assuming a 30-day mortality of 5% in both randomised groups. Once randomised, definitive treatment will be for a minimum of 5 days and a maximum of 14 days with the total duration determined by treating clinicians. Data describing demographic information, risk factors, concomitant antibiotics, illness scores, microbiology, multidrug-resistant organism screening, discharge and mortality will be collected. DISCUSSION: Participants will have bloodstream infection due to third-generation cephalosporin non-susceptible E. coli and Klebsiella spp. or Enterobacter spp., Citrobacter freundii, Morganella morganii, Providencia spp. or Serratia marcescens. They will be randomised 1:1 to ceftolozane-tazobactam 3 g versus meropenem 1 g, both every 8 h. Secondary outcomes will be a comparison of 14-day all-cause mortality, clinical and microbiological success at day 5, functional bacteraemia score, microbiological relapse, new bloodstream infection, length of hospital stay, serious adverse events, C. difficile infection, multidrug-resistant organism colonisation. The estimated trial completion date is December 2024. TRIAL REGISTRATION: The MERINO-3 trial is registered under the US National Institute of Health ClinicalTrials.gov register, reference number: NCT04238390 . Registered on 23 January 2020.

Antimicrobial treatment challenges in the era of carbapenem resistance.

Infections due to carbapenem-resistant Gram-negative bacteria are burdened by high mortality and represent an urgent threat to address. Clinicians are currently at a dawn of a new era in which antibiotic resistance in Gram-negative bacilli is being dealt with by the availability of the first new antibiotics in this field for many years. Although new antibiotics have shown promising results in clinical trials, there is still uncertainty over whether their use will improve clinical outcomes in real world practice. Some observational studies have reported a survival benefit in carbapenem-resistant Enterobacteriaceae bloodstream infections using combination therapy, often including "old" antibiotics such as colistin, aminoglycosides, tigecycline, and carbapenems. These regimens, however, are linked to increased risk of antimicrobial resistance, and their efficacy has yet to be compared to new antimicrobial options. While awaiting more definitive evidence, antibiotic stewards need clear direction on how to optimize the use of old and novel antibiotic options. Furthermore, carbapenem-sparing regimens should be carefully considered as a potential tool to reduce selective antimicrobial pressure.

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.

Copper Ions and Coordination Complexes as Novel Carbapenem Adjuvants.

Carbapenem-resistant Enterobacteriaceae are urgent threats to global human health. These organisms produce ß-lactamases with carbapenemase activity, such as the metallo-ß-lactamase NDM-1, which is notable due to its association with mobile genetic elements and the lack of a clinically useful inhibitor. Here we examined the ability of copper to inhibit the activity of NDM-1 and explored the potential of a copper coordination complex as a mechanism to efficiently deliver copper as an adjuvant in clinical therapeutics. An NDM-positive Escherichia coli isolate, MS6192, was cultured from the urine of a patient with a urinary tract infection. MS6192 was resistant to antibiotics from multiple classes, including diverse ß-lactams (penicillins, cephalosporins, and carbapenems), aminoglycosides, and fluoroquinolones. In the presence of copper (range, 0 to 2 mM), however, the susceptibility of MS6192 to the carbapenems ertapenem and meropenem increased markedly. In standard checkerboard assays, copper decreased the MICs of ertapenem and meropenem against MS6192 in a dose-dependent manner, suggesting a synergistic mode of action. To examine the inhibitory effect of copper in the absence of other ß-lactamases, the blaNDM-1 gene from MS6192 was cloned and expressed in a recombinant E. coli K-12 strain. Analysis of cell extracts prepared from this strain revealed that copper directly inhibited NDM-1 activity, which was confirmed using purified recombinant NDM-1. Finally, delivery of copper at a low concentration of 10 µM by using the FDA-approved coordination complex copper-pyrithione sensitized MS6192 to ertapenem and meropenem in a synergistic manner. Overall, this work demonstrates the potential use of copper coordination complexes as novel carbapenemase adjuvants.