Our weekly wrap-up of antimicrobial stewardship & antimicrobial resistance scans
Mixed results in trial of fosfomycin for bacterimic urinary tract infections
A randomized clinical trial found that fosfomycin did not demonstrate noninferiority to comparator antibiotics for bacteremic urinary tract infections (bUTIs) caused by multidrug-resistant (MDR) Escherichia coli, but it could remain an option for select patients, researchers reported yesterday in JAMA Network Open.
In the trial, which included patients recruited from 22 Spanish hospitals from June 2014 through December 2018, investigators randomly assigned 70 participants to receive intravenous fosfomycin disodium and 73 to receive ceftriaxione or meropenem (if the infection was resistant to ceftriaxone). The primary outcome was clinical and microbiologic cure (CMC) 5 to 7 days after finalization of treatment. The noninferiority margin was 7%.
The rates of CMC were 68.6% in the fosfomycin group and 78.1% in the comparator group (difference, –9.4 percentage points). While fosfomycin failed to achieve noninferiority criteria, the study authors note that it was not due to lack of efficacy. Clinical failure rates were lower in the fosfomycin patients (14.3% vs 19.7%; difference, –5.4 percentage points). And among patients with severe sepsis, the CMC rate was higher in the fosfomycin group (86.7%) than in the comparator group (72.7%), a finding the authors say reinforces the idea that fosfomycin is efficacious in this infection.
In addition, an exploratory analysis of 38 patients who underwent rectal colonization studies found that none of the patients treated with fosfomycin acquired a new ceftriaxone- or meropenem-resistant gram-negative bacterial infection, compared with 23.5% in the comparator group.
However, six patients in the fosfomycin group had to discontinue treatment, four of them because of heart failure.
"Fosfomycin did not demonstrate noninferiority in the treatment of bUTI caused by MDR E coli," the authors wrote. "However, the data suggest that the drug is effective and may be considered among selected patients, particularly those without previous heart disease and with low risk of sodium overload–related problems."
The authors of an accompanying commentary conclude that the results suggest that fosfomycin, a drug discovered more than 50 years ago, may have utility as a carbapenem-sparing strategy for extended-spectrum beta-lactam E coli infections, and should be further explored.
Jan 13 JAMA Netw Open study
Jan 13 JAMA Netw Open commentary
Rising echinocandin resistance found in NY Candida auris isolates
A study of clinical Candida auris isolates from New York shows increasing resistance to echinocandins, researchers reported this week in Antimicrobial Agents and Chemotherapy.
The researchers looked at clinical C auris isolates from healthcare facilities in New York and New Jersey, which together accounted for 55% of US C auris cases reported from 2016 through 2020. Among the 1,148 isolates from 697 patients in New York, all were resistant to fluconazole from 2016 through 2019, with resistance dropping slightly in 2020 (99.6%). Amphotericin B resistance fell from 82.1% in 2016 to 45.3% in 2019.
There was no resistance to echinocandins among the 2016 isolates, but echinocandin resistance rose to 4% by 2020. Ten isolates were found to be resistant to all three antifungals.
Among the 134 isolates from 121 patients in New Jersey, all were resistant to fluconazole, none were resistant to echinocandins, and amphotericin B resistance fell from 66.7% in 2017 to 31.1% in 2020.
The study authors said the precise mechanism behind differences in echinocandin resistance and pan-resistance between the New York and New Jersey isolates is unclear. "The observed resistance pattern might reflect intraregional differences in antifungal treatment practices, but further investigations are needed for confirmation," they wrote.
In its most recent update last fall, the Centers for Disease Control and Prevention (CDC) reported a total of 938 confirmed C auris infections in 21 states from September 2020 through August 2021, along with 3,034 patients colonized with the organism. The MDR yeast, which spreads easily in healthcare settings and can cause severe and deadly invasive infections in immunocompromised patients, was first identified in Japan in 2009 and first appeared in the United States in 2013.
Jan 10 Antimicrob Agents Chemother abstract
Oct 27 CDC Candida auris update
CRISPR-based E coli drug gets go-ahead for first human trial
Originally published by CIDRAP News Jan 13
Danish microbiome technology company SNIPR Biome ApS announced this week that the US Food and Drug Administration has approved the company's application to initiate the first human clinical trial of its CRISPR-based drug for preventing E coli infections in cancer patients.
The clinical trial for SNIPR001, which uses CRISPR/Cas DNA editing technology to selectively target and eradicate E coli bacteria in the gut and prevent translocation of the bacteria to the bloodstream while leaving other commensal bacteria unaffected, will investigate safety and tolerability of the drug in healthy volunteers. Investigators will also evaluate the effect of SNIPR001 on gut E coli.
Patients with cancer of the blood, bone marrow, and lymph nodes are at increased risk of life-threatening bloodstream infections because of immune-suppressing chemotherapy treatments and pathogen translocation from the gut, and E coli can pose a heightened risk for such infections.
Company officials say they believe the approach could transform the way E coli infections are prevented and treated, in cancer wards and beyond.
"Based on our pre-clinical data with SNIPR001, we believe that our technology holds a huge potential in designing tomorrow's CRISPR-based medicines against life-threatening infections and to modulate microbiome-associated diseases," Milan Zdravkovic, MD, PhD, chief medical officer at SNIPR Biome, said in a company press release.
SNIPR Biome received $3.9 million in funding from CARB-X (the Combating Antibiotic Resistant Bacteria Biopharmaceutical Accelerator) to develop SNIPR001 in May 2021.
Jan 11 SNIPR Biome press release
Study highlights inappropriate prescribing for respiratory infections
Originally published by CIDRAP News Jan 12
A study of 42 million US patient visits for antibiotic-inappropriate acute respiratory infections (ARIs) found that more than 10% received an antibiotic prescription, with providers in urgent care clinics and southern states among the most likely prescribers, US researchers reported this week in Infection Control & Hospital Epidemiology.
The study, conducted by researchers from the CDC and IQVIA using IQVIA's medical claims and prescription databases, looked at 41.97 million patient visits from October 2018 through September 2019 with diagnosis codes for ARIs for which antibiotics are generally not indicated. These included asthma, allergy, bronchitis, bronchiolitis, flu, viral upper respiratory infection, and non-suppurative otitis media (earache).
The researchers calculated the Prescriber Inappropriate Antibiotic Prescribing Index (PIAPI) as the proportion of a clinician's visits for antibiotic-inappropriate ARIs that received an antibiotic, and used a machine-learning model to determine drivers of PIAPI.
The average PIAPI was 11%, meaning that clinicians prescribed antibiotics in 11% of visits for which the drugs were unnecessary. The machine-learning model identified outpatient setting, patient-age mix, and state as the strongest predictors of PIAPI. Among settings, average PIAPI ranged from 5% in outpatient hospital clinics to 21% in urgent care facilities. Clinicians who saw children predominantly had a lower average PIAPI (7%) than those who saw adults or balanced age mixes (11%–13%). The researchers also detected wide variation by state, with the highest average PIAPIs in southern states, including Mississippi (17%) and Alabama (18%).
"This project demonstrated that machine-learning may be valuable in targeting antibiotic stewardship interventions," the study authors wrote.
Jan 10 Infect Control Hosp Epidemiol abstract
Mass azithromycin distribution in Niger tied to reduction in Shigella in kids
Originally published by CIDRAP News Jan 12
A study of children in Niger who received biannual administration of azithromycin found a substantial reduction in Shigella carriage after 2 years, researchers reported this week in Clinical Infectious Diseases.
In the study, researchers from the United States and Niger analyzed rectal samples from children in 30 villages in Niger that had participated in the MORDOR I trial, which randomized children in Niger, Malawi, and Tanzania to receive biannual administration of azithromycin or placebo. Using polymerase chain reaction (PCR) assays, the researchers screened the samples for 29 enteropathogens at baseline and at 24 months.
At baseline, five pathogens had a baseline prevalence of greater than 2%: enteroaggregative E coli (21.7%), Shigella (14.1%), Campylobacter jejeuni or Campylobacter coli (12.9%), enterotoxigenic E coli (11.8%), and typical enteropathogenic E coli (3.8%). There were no differences in pathogen quantity by trial arm.
At 24 months, however, the prevalence of Shigella in samples from the villages randomized to azithromycin was 64% lower than those from placebo villages (prevalence ratio, 0.36; 95% confidence interval [CI], 0.17 to 0.97), corresponding to an absolute prevalence difference of –11.1% (95% CI, –19.4% to –2.8%). No other differences in pathogen quantity or prevalence were observed.
The study authors say the findings could partly account for the 18.1% reduction in mortality observed in the Niger cohort in the MORDOR I trial, which was the largest mortality reduction observed among the three countries in the study. In addition, they note that analysis of verbal autopsies conducted in Niger following MORDOR I have found reductions in incidence and deaths from dysentery, which can be caused by Shigella.
"In summary, we found a significant reduction in Shigella carriage from a high baseline among children 1-59 months of age in villages that received biannual azithromycin instead of placebo," they wrote. "Together with reports demonstrating a substantial decrease in dysentery incidence, these findings suggest that a reduction in Shigella infections may have contributed to the observed reduction in mortality."
Jan 10 Clin Infect Dis abstract
Apr 26, 2018 CIDRAP News scan on MORDOR trial
Review finds too few innovative drugs in antibiotic development pipeline
Originally published by CIDRAP News Jan 11
A new review of the antibiotic development pipeline finds that there are relatively few clinically differentiated products in late-stage clinical development, especially against critical, multidrug-resistant pathogens, an international team of researchers reported yesterday in Antimicrobial Agents and Chemotherapy.
The review, which looked at all traditional and non-traditional antibacterial drug candidates that were being evaluated in clinical trials as of Jun 30, 2021, found a total of 76 products, 45 of which are traditional antibacterial agents and 31 of which are non-traditional. Sixty of those candidates (79%) are in phase 1 (28) or phase 2 (32) trials, with 12 in phase 3 trials and 4 under regulatory review.
Of the 76 candidates, 42 are being developed to target the pathogens deemed critical (26) and high/medium priority (16) by the World Health Organization. In addition, 16 products are being developed to treat mycobacterial infections (14 for tuberculosis and 2 for non-tuberculosis mycobacteria) and 15 to treat Clostridioides difficile infections. But only 18 of the antibacterial agents in development have new pharmacophores, which is one of the components that can determine whether an antibacterial candidate belongs to a new class or sub-class of antibiotics, and only 4 have new, overarching modes of action.
The review also found that 12 new antibacterial products have been approved globally since 2017, but only 1 (vaborbactam) belongs to a new antibiotic class.
While the review authors note that the overall number of antibacterial candidates being evaluated in clinical trials is promising, the small number of clinically differentiated agents targeting priority pathogens that are in late-stage development, and the dearth of innovative new products, remains a problem. They say there needs to be a research and development (R&D) focus on "quality over quantity" to address increasing numbers of multidrug-resistant infections.
"It is important to try and keep on identifying and developing antibacterial agents with new modes of action to try and slow down antibacterial drug resistance," they wrote. "Furthermore, we believe that future antibacterial R&D should focus on the development of innovative and clinically differentiated candidates that have clear and feasible progression pathways right through development and onto the market."
Jan 10 Antimicrob Agents Chemother abstract
Collaboration aims to boost use of diagnostics to combat resistance
Originally published by CIDRAP News Jan 11
Medical technology company BD (Becton, Dickinson and Company) today announced a partnership with pharmaceutical company Pfizer and global nonprofit Wellcome to explore the role diagnostics can play in advancing antimicrobial stewardship and combating antimicrobial resistance (AMR).
The collaboration will survey existing diagnostic practices in healthcare settings to highlight the benefits of diagnostic testing for stewardship, as well as the gaps. Proper use of diagnostic testing to distinguish between bacterial and viral infections can play a critical role in reducing unnecessary antibiotic and antifungal use and slowing the emergence of AMR, but diagnostics remain underused, company officials said in a press release.
"Diagnostic stewardship—meaning coordinated guidance and interventions to improve appropriate use of microbiological diagnostics to guide therapeutic decisions—promotes appropriate, timely diagnostic testing, including specimen collection and pathogen identification as well as accurate, timely reporting of results to guide patient treatment," said Brooke Story, MBA, president of Integrated Diagnostic Solutions for BD.
"Research shows us that significant barriers must be overcome to make health care workers aware of the importance and positive impact of diagnostics on AMR."
Gemma Buckland-Merrett, PhD, research lead for drug-resistant infections at Wellcome, said the collaboration will help address these challenges and contribute to better outcomes for patients and the healthcare system. "Having the right diagnostic tools for the right contexts, and ensuring their uptake is crucial to fight antimicrobial resistance and save modern medicine," she said.
Jan 11 BD press release