Determination of the De Novo Minimum Selection Concentration of Trimethoprim In Vivo for Using A Pilot Study.

We investigated whether the maximum residual levels of trimethoprim permitted in food (Acceptable Daily Intake-ADI) could select for de novo trimethoprim resistance in in vivo. We designed chronic infection models of in and exposed them to sub-ADI doses of trimethoprim through a single-dosing regimen. The emergence of trimethoprim resistance was determined by isolating the target bacteria on selective agar plates, followed by species confirmation using MALDI-TOF mass spectrometry.

Measuring individual colony MICs is a more sensitive method to detect the effect of antimicrobials on antimicrobial susceptibility than the proportion of colonies resistant.

Unlabelled: The ResistAZM randomized controlled trial found that the receipt of ceftriaxone/azithromycin, compared to ceftriaxone was not associated with an increase in the proportion of oral commensal Neisseria spp. and streptococci with azithromycin resistance 14 days after treatment. We repeated the analyses by measuring the minimum inhibitory concentrations (MICs) of azithromycin and ceftriaxone for individual colonies of commensal Neisseria spp.

Macrolide resistance is pervasive in oral streptococci in the Belgian general population: a cross-sectional survey.

Commensal streptococci are common inhabitants of the oral microbiome and regulate its structure and function in beneficial ways for human health. They can, however, also be opportunistic pathogens and act as a reservoir of resistance genes that can be passed on to other bacteria, including pathogens. Little is known about the prevalence of these commensals in parents and their children and their antimicrobial susceptibilities in the Belgian general population.

Antimicrobial susceptibility of commensal Neisseria spp. in parents and their children in Belgium: a cross-sectional survey.

Background: commensal Neisseria species are part of the oropharyngeal microbiome and play an important role in nitrate reduction and protecting against colonization by pathogenic bacteria. They do, however, also serve as a reservoir of antimicrobial resistance. Little is known about the prevalence of these species in the general population, how this varies by age and how antimicrobial susceptibility varies between species.

The Prevalence of Antibiotic Tolerance in Varies by Anatomical Site.

Background: Tolerance enables bacteria to survive intermittent antibiotic exposure without an increase in antimicrobial susceptibility. In this study, we investigated the presence of tolerance to three antimicrobials, ceftriaxone, azithromycin and ciprofloxacin, in clinical isolates and the WHO (World Health Organization) reference panel of .

Methods: We used the modified tolerance disk (TD test) to assess for tolerance to ceftriaxone, azithromycin and ciprofloxacin in 14 WHO reference strains and 62 clinical isolates-evenly divided between anorectal and urogenital infections.

Effect of erythromycin residuals in food on the development of resistance in : an study in .

Background: The use of antimicrobials to treat food animals may result in antimicrobial residues in foodstuffs of animal origin. The European Medicines Association (EMA) and World Health Organization (WHO) define safe antimicrobial concentrations in food based on acceptable daily intakes (ADIs). It is unknown if ADI doses of antimicrobials in food could influence the antimicrobial susceptibility of human-associated bacteria.

Could the effect of antimicrobials on antimicrobial resistance be saturated at high-antimicrobial consumption? A comparison of the MORDOR and ResistAZM studies.

Objectives: Antimicrobial resistance poses a considerable threat in high-antimicrobial-consumption populations, such as men who have sex with men (MSM) taking HIV pre-exposure prophylaxis. While the ResistAZM trial found no increase in macrolide resistance genes in MSM with gonorrhea after azithromycin treatment, the MORDOR trial observed an increase in these genes after mass azithromycin distribution. We hypothesized that this could be due to saturation of the resistome.

Could traces of fluoroquinolones in food induce ciprofloxacin resistance in and ? An study in with important implications for maximum residue limits in food.

We hypothesized that the residual concentrations of fluoroquinolones allowed in food (acceptable daily intake-ADIs) could select for ciprofloxacin resistance in our resident microbiota. We developed models of chronic and infection in larvae and exposed them to ADI doses of ciprofloxacin via single dosing and daily dosing regimens. The emergence of ciprofloxacin resistance was assessed via isolation of the target bacteria in selective agar plates.

Four recent insights suggest the need for more refined methods to assess the resistogenicity of doxycycline post exposure prophylaxis.

Two recently published randomized trials of doxycycline post exposure prophylaxis (PEP) have concluded that this intervention is highly effective at reducing the incidence of bacterial sexually transmitted infections (STIs) and has little or no risk of promoting the spread of antimicrobial resistance (AMR). In this perspective piece, we review four types of evidence that suggest that the risk of promoting AMR has been inadequately assessed in these studies. 1) The studies have all used proportion resistant as the outcome measure.

45 years of tetracycline post exposure prophylaxis for STIs and the risk of tetracycline resistance: a systematic review and meta-analysis.

There is considerable interest in the use of doxycycline post exposure prophylaxis (PEP) to reduce the incidence of bacterial sexually transmitted infections (STIs). An important concern is that this could select for tetracycline resistance in these STIs and other species. We searched PubMed and Google Scholar, (1948-2023) for randomized controlled trials comparing tetracycline PEP with non-tetracycline controls.

Protective effect of microbisporicin (NAI-107) against vancomycin resistant Enterococcus faecium infection in a Galleria mellonella model.

Increasing antimicrobial resistance in Enterococcus faecium necessitates the search for novel treatment agents, such as bacteriocins. In this study, we conducted an in vivo assessment of five bacteriocins, namely Lacticin Z, Lacticin Q, Garvicin KS (ABC), Aureocin A53 and Microbisporicin (NAI-107), against vanB-resistant Enterococcus faecium using a Galleria mellonella model. Our in vitro experiments demonstrated the efficacy of all five bacteriocins against vanB-resistant E.

Lack of Association between Antimicrobial Consumption and Antimicrobial Resistance in a HIV Preexposure Prophylaxis Population: A Cross-Sectional Study.

Background: In antibiotic naïve populations, there is a strong association between the use of an antimicrobial and resistance to this antimicrobial. Less evidence is available as to whether this relationship is weakened in populations highly exposed to antimicrobials. Individuals taking HIV preexposure prophylaxis (PrEP) have a high intake of antimicrobials.

Gonococcal resistance to zoliflodacin could emerge via transformation from commensal Neisseria species. An in-vitro transformation study.

One of the most promising new treatments for gonorrhoea currently in phase 3 clinical trials is zoliflodacin. Studies have found very little resistance to zoliflodacin in currently circulating N. gonorrhoeae strains, and in-vitro experiments demonstrated that it is difficult to induce resistance.

Ramoplanin as a novel therapy for infection: an and study in .

is a bacterial pathogen that causes gonorrhoea, a sexually transmitted infection. Increasing antimicrobial resistance in is providing motivation to develop new treatment options. In this study, we investigated the effectiveness of the antibiotic ramoplanin as a treatment for infection.

Effect on the Resistome of Dual vs Monotherapy for the Treatment of : Results From a Randomized Controlled Trial (ResistAZM Trial).

Background: No randomized controlled trial (RCT) has compared the impact on the resistome of ceftriaxone (CRO) plus azithromycin (AZM) vs CRO for the treatment of (NG).

Methods: This was an open-label, single-center, RCT comparing the effect on the resistome of CRO plus AZM vs CRO for the treatment of NG. Men who have sex with men (MSM) with genital, anorectal, or pharyngeal NG infection were randomized into the CRO/AZM and CRO arms.