Antibiotic consumption and resistance of gram-negative pathogens (collateral damage)

Adverse Drug Reactions Related with Antibiotic Medicines in Malawi: A Retrospective Analysis of Prevalence and Associated Factors

Objective

We aimed to assess the occurrence and characteristics of antibiotic-associated adverse drug reactions (ADRs) in Malawi.

Methods

We retrospectively reviewed 304 patient records from medical wards in three hospitals in Southern Malawi. A global trigger tool was applied for the detection of suspected ADRs, and we used the Naranjo scale, the World Health Organization classification and the Schumock and Thornton scale for causality, seriousness and preventability assessment respectively. ADRs were also further characterized according to anatomical systems. Statistical analysis was done in STATA 14.1. The Chi-square test was used to determine the association between categorical variables and logistic regression analysis was used to measure the strength of the association between various independent variables and the occurrence of ADRs.

Results

Suspected ADRs were detected in 24% (73/304) of patients, of which 1.4% were definite, 15.1% were probable and 83.6% were possible ADRs. Most of the sADRs were gastrointestinal events (42.5%), followed by: musculoskeletal (26.3%); cardiovascular (16.3%); central nervous system (13.8%; and urinary events (1.3%). About 27% of the sADRs were serious events such as convulsions. The geriatric age group (≥65 years) was more likely to experience sADRs as compared to the younger age group, with an adjusted odds ratio (aOR) of 4.53, 95% CI (2.21-9.28), P<0.001. Patients taking more than one antibiotic medicine had a higher risk of developing sADRs as compared to patients who were administered one type of antibiotic medicine, aOR 2.14, 95% CI (1.18-3.90), p < 0.012. A long hospital stay of >3days was associated with a higher risk of sADRs with aOR of 5.11, 95% CI (2.47-10.55), p < 0.001 than those who stayed ≤ 3 days in the hospital.

Conclusion

We found a higher prevalence of serious sADRs associated with antibiotic medicines than reported elsewhere. This may, among others, contribute to high patient mortality, poor treatment adherence, antibiotic resistance and increased cost of care.

The impact of antibiotic exposure on antibiotic resistance gene dynamics in the gut microbiota of inflammatory bowel disease patients

Background

While antibiotics are commonly used to treat inflammatory bowel disease (IBD), their widespread application can disturb the gut microbiota and foster the emergence and spread of antibiotic resistance. However, the dynamic changes to the human gut microbiota and direction of resistance gene transmission under antibiotic effects have not been clearly elucidated.

Methods

Based on the Human Microbiome Project, a total of 90 fecal samples were collected from 30 IBD patients before, during and after antibiotic treatment. Through the analysis workflow of metagenomics, we described the dynamic process of changes in bacterial communities and resistance genes pre-treatment, during and post-treatment. We explored potential consistent relationships between gut microbiota and resistance genes, and established gene transmission networks among species before and after antibiotic use.

Results

Exposure to antibiotics can induce alterations in the composition of the gut microbiota in IBD patients, particularly a reduction in probiotics, which gradually recovers to a new steady state after cessation of antibiotics. Network analyses revealed intra-phylum transfers of resistance genes, predominantly between taxonomically close organisms. Specific resistance genes showed increased prevalence and inter-species mobility after antibiotic cessation.

Conclusion

This study demonstrates that antibiotics shape the gut resistome through selective enrichment and promotion of horizontal gene transfer. The findings provide insights into ecological processes governing resistance gene dynamics and dissemination upon antibiotic perturbation of the microbiota. Optimizing antibiotic usage may help limit unintended consequences like increased resistance in gut bacteria during IBD management.

The impact of implementation of rapid blood culture identification panels on antimicrobial optimization: a retrospective cohort study

Objective

Determine the impact of limited implementation of a rapid blood culture identification (BCID) panel.

Design

Retrospective cohort study.

Methods

From February to April 2022, positive blood cultures identified via e-Plex BCID (Roche, Carlsbad, CA) were compared to those identified using standard microbial identification techniques. The primary outcomes assessed were time to optimal therapy, time to de-escalation of anti-MRSA (methicillin-resistant Staphylococcus aureus) agents, and time to de-escalation of anti-pseudomonal agents. Additional analysis investigated the impact of the availability of antimicrobial stewardship program support. This study was conducted at Grady Health System, a large metropolitan safety-net hospital in the southeastern United States.

Results

A total of 253 blood cultures were included in this study (153 BCID and 100 standard). Blood culture identification use was associated with a reduction in median time to optimal antimicrobial therapy (43.4 vs 72.1 h, P < .001) and median time to de-escalation of anti-MRSA agents (27.7 vs 46.7 h, P = .006), and a trend towards reduction of median time to de-escalation of anti-pseudomonal agents (38.8 vs 54.8 h, P = .07). These reductions persisted when controlling for patient age, sex, intensive care unit status, Charlson Comorbidity Index, and antimicrobial stewardship program availability.

Conclusions

Despite restricted use and lack of 24/7 antimicrobial stewardship program availability, BCID panel utilization was associated with earlier initiation of optimal therapy and pathogen identification with subsequent de-escalation of broad-spectrum antimicrobials, as compared to standard antimicrobial techniques. This suggests the potential for benefit from adopting novel diagnostic technologies outside of idealized fully-resourced settings.

Enhancement by pyrazolones of colistin efficacy against mcr-1-expressing E. coli: an in silico and in vitro investigation

Owing to the emergence of antibiotic resistance, the polymyxin colistin has been recently revived to treat acute, multidrug-resistant Gram-negative bacterial infections. Positively charged colistin binds to negatively charged lipids and damages the outer membrane of Gram-negative bacteria. However, the MCR-1 protein, encoded by the mobile colistin resistance (mcr) gene, is involved in bacterial colistin resistance by catalysing phosphoethanolamine (PEA) transfer onto lipid A, neutralising its negative charge, and thereby reducing its interaction with colistin. Our preliminary results showed that treatment with a reference pyrazolone compound significantly reduced colistin minimal inhibitory concentrations in Escherichia coli expressing mcr-1 mediated colistin resistance (Hanpaibool et al. in ACS Omega, 2023). A docking-MD combination was used in an ensemble-based docking approach to identify further pyrazolone compounds as candidate MCR-1 inhibitors. Docking simulations revealed that 13/28 of the pyrazolone compounds tested are predicted to have lower binding free energies than the reference compound. Four of these were chosen for in vitro testing, with the results demonstrating that all the compounds tested could lower colistin MICs in an E. coli strain carrying the mcr-1 gene. Docking of pyrazolones into the MCR-1 active site reveals residues that are implicated in ligand-protein interactions, particularly E246, T285, H395, H466, and H478, which are located in the MCR-1 active site and which participate in interactions with MCR-1 in ≥ 8/10 of the lowest energy complexes. This study establishes pyrazolone-induced colistin susceptibility in E. coli carrying the mcr-1 gene, providing a method for the development of novel treatments against colistin-resistant bacteria.

Sequence specificity defines the effectiveness of PPMOs targeting Pseudomonas aeruginosa

Development of new therapeutics against antibiotic resistant pathogenic bacteria is recognized as a priority across the globe. We have reported using peptide-conjugated phosphorodiamidate morpholino oligomers (PPMOs) as species-specific antibiotics. The oligo sequences, 11 bases are designed to be complementary to specific essential genes near the Shine-Dalgarno site and inhibit translation. Here, we analyzed target specificity and the impact of genetic mutations on lead PPMOs targeting the rpsJ or acpP gene of Pseudomonas aeruginosa. Mutants in P. aeruginosa PAO1 were generated with four, two, or one base-pair mutations within the 11-base target sequence of the rpsJ gene. All mutants exhibited increased MICs compared to wild-type PAO1 when treated with the RpsJ PPMO, and the increase in the MICs was proportional to the number of base-pair mutations. Among single base-pair mutants, mutations in the middle of the sequence were more impactful than mutations in 5' or 3' end of the sequence. The increased MICs shown by the rpsJ mutants could be reversed by PPMOs designed to target the mutated rpsJ sequence. BALB/c mice infected intratracheally with mutants demonstrated increased lung burden when treated with RpsJ PPMO compared to wild-type PAO1-infected mice treated with RpsJ PPMO. Treating mice with a PPMOs designed to specifically target the mutant sequence was more effective against these mutant strains. These experiments confirm target specificity of two lead P. aeruginosa PPMOs and illustrate one potential mechanism of resistance that could emerge from an antisense approach.

Low Rate of Bacterial Coinfections and Antibiotic Overprescribing During COVID-19 Pandemic: A Retrospective Study from Oman

Objectives

The recommended treatment for COVID-19 includes antiviral drugs, corticosteroids, immunomodulatory drugs, low molecular weight heparin, as well as antibiotics. Although COVID-19 is a viral disease, many studies indicate that antibiotics are prescribed frequently, mainly to treat suspected bacterial coinfection. At the same time, the prevalence of bacterial coinfections during COVID-19 is rather low indicating the significant antibiotic overuse in these patients. It is well known that this can trigger antibiotic bacterial resistance, and once it emerges the reversal of resistance is a complex and long-lasting process. The aims of this study were to estimate the prevalence of bacterial coinfections during the COVID-19 and to analyze the antibiotic treatment justification during this pandemic in Oman.

Methods

This retrospective analysis was conducted using the Royal Hospital COVID-19 Registry Database. The study analyzed demographic and clinical characteristics, as well as laboratory parameters and antibiotic treatment of hospitalized patients.

Results

During the study period, 584 patients were enrolled in the analysis. Coinfection was rare as it was confirmed in 0.9% of patients. Superinfections were present in 15.2% of patients. Gram-negative bacteria were isolated in 95 (69.9%) samples, gram-positive bacteria in 25 (18.4%) samples, while Candida spp. was found in 16 (11.8%) samples. On admission, empirical antibiotic treatment was started in 543 (93.0%) patients.

Conclusions

During COVID-19, coinfections are rarely seen and the overuse of antibiotics is not justified. The incidence of superinfections is the same as in other patients in healthcare settings caused by the same resistant microorganisms, which implies the use of even more.

Association between Consumption of Fluoroquinolones and Carbapenems and Their Resistance Rates in Pseudomonas aeruginosa in Argentina

Background. Irrational use of antimicrobials (ATMs) triggers microbial resistance (AMR) which has severe consequences for human health. ATM consumption varies among countries and within each territory. These data should be known, in order to perform local policies towards AMR reduction. This work aimed to expose the association of the level of consumption of carbapenems and fluoroquinolones with their resistance rates in Pseudomonas aeruginosa in Argentina. Method. Consumption of antimicrobials was expressed by defined daily dose (DDD)/1000 inhabitants for each ATM during one year period, discriminating by each country region. Resistance of P. aeruginosa to carbapenems/fluoroquinolones groups was recorded. Consumption/resistance ratio “R” was calculated for each region of the country, comparing results with other countries. Results. P. aeruginosa resistance rate to fluoroquinolone (F) was 26.4% in blood samples and 29.7% in urine samples, whereas resistance rates to carbapenems (C) were 19.9 and 17.7% in blood and urine, respectively. Correlation between consumption and resistance was demonstrated for both antimicrobials (C : R = 0.58; $p=0.003$ and F : R = 0.77; $p=0.0001$ ). Great fluctuations of resistance levels were seen among regions within the country, always correlating resistance with areas in which a higher level of ATM consumption was detected. Conclusion. P. aeruginosa resistance to fluoroquinolone/carbapenems in Argentina directly correlated with antimicrobial consumption levels. A great heterogeneity in resistance profile was observed among areas where ATMs were widely used. Global data at the national level might mask local realities that require specific health policies in order to control the irrational use of ATMs.

Antimicrobial stewardship programs in emergency departments: how do we measure antimicrobial use? A systematic review

OBJECTIVE

The implementation of antimicrobial stewardship programs (ASPs) has become a usual practice in hospital settings. However, the method for monitoring antimicrobial use in accident and emergency departments (ED) is not yet adequately defined. Thus, the objective of this review is to describe antimicrobial use indicators used by ASPs implemented in ED.

METHODS

A systematic review was performed based on studies found in the following academic research databases: MEDLINE, EMBASE, Web of Science, and Scopus (Period: January 2000 to December 2019). Controlled clinical trials, before-and-after studies, interrupted time series, and repeated measures studies assessing the impact of ASPs on antimicrobial use in ED were included; studies published in languages other than English or Spanish were excluded from this review.

RESULTS

Twenty-six studies met the inclusion criteria and were included in this systematic review. In total, 15 (62.5%) studies described the ASP team members who collaborated with the ED staff. Most (21; 80.8%) studies used the percentage of patients with an antibiotic prescription as an indicator. Four (15.4%) studies included defined daily dose data. The antibiotic treatment duration was reported in four (15.4%) studies. Only two studies assessed the impact of the ASP using microbiological indicators, both of which used the incidence of infection with Clostridioides difficile as the indicator.

CONCLUSIONS

The reports of experiences in implementing ASPs in ED show heterogeneous antimicrobial use indicators, which makes it difficult to compare results. Therefore, antimicrobial use indicators for ASPs must be standardised between hospital units.

Disparities in antimicrobial consumption and resistance within a country: the case of beta-lactams in Argentina

Objective.

To describe bacterial resistance and antimicrobial consumption ratio at the subnational level in Argentina during 2018, considering beta-lactams group as a case-study.

Methods.

Antimicrobial consumption was expressed as defined daily doses (DDD)/1000 inhabitants. Resistance of Escherichia coli, Streptococcus pneumoniae, Pseudomonas aeruginosa, Klebsiella pneumoniae and Staphylococcus aureus to beta-lactams was recorded. Resistance/consumption ratio was estimated calculating “R” for each region of Argentina, and this data was compared with other countries.

Results.

The most widely consumed beta-lactams in Argentina were amoxicillin (3.64) for the penicillin sub-group, cephalexin (0.786) for first generation cephalosporins, cefuroxime (0.022) for second generation; cefixime (0.043) for third generation and cefepime (0.0001) for the fourth generation group. Comparison between beta-lactams consumption and bacterial resistance demonstrated great disparities between the six regions of the country.

Conclusions.

The case-study of Argentina shows that antimicrobial consumption and resistance of the most common pathogens differed among regions, reflecting different realities within the same country. Because this situation might also be occurring in other countries, this data should be taken into account to target local efforts towards better antimicrobial use, to improve antimicrobial stewardship programs and to propose more suitable sales strategies in order to prevent and control antimicrobial resistance.

Impact of Accelerate Pheno and BacT/Alert Virtuo on Clinical Processes and Outcomes in Patients with Sepsis and Concurrent Gram-Negative Bacteremia

The Accelerate Pheno and BacT/Alert Virtuo systems may improve bacteremia management. Here, we evaluated the impact of both devices on outcomes in patients with sepsis and concurrent Gram-negative bacteremia. This quasiexperimental study included a retrospective preimplementation and a prospective postimplementation group. Patients ≥18 years old with Gram-negative bacteremia were included. Patients with neutropenia, pregnant patients, those who were transferred from an outside hospital with active bloodstream infections, and those with polymicrobial bacteremia were excluded. Blood culture incubation in the BacT/Alert 3D device and microdilution antimicrobial susceptibility testing from culture plate growth were used prior to implementation of the BacT/Alert Virtuo and Accelerate Pheno systems. Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) identification directly from blood culture was used pre- and postimplementation. Time to Gram stain results, identification, susceptibility reporting, initiation of narrow-spectrum Gram-negative therapy at 72 h, 30-day inpatient mortality, sepsis resolution, and length of hospital stay were evaluated. A total of 116 patients were included (63 preimplementation, 53 postimplementation). Median times to Gram stain and susceptibility results were significantly shorter postimplementation (P < 0.001). The postimplementation group had an improved hazard ratio for narrow-spectrum Gram-negative therapy at 72 h (hazard ratio [HR], 2.685 [95% confidence interval {CI}, 1.348 to 5.349]), a reduced hazard ratio for 30-day inpatient mortality (adjusted HR [aHR], 0.150 [95% CI, 0.026 to 0.846]), and improved sepsis resolution (92.5% versus 77.8% [P = 0.030]). The length of hospital stay was unchanged after implementation. We conclude that implementation of the BacT/Alert Virtuo and Accelerate Pheno systems improved microbiology laboratory processes, antibiotic utilization processes, and clinical outcomes. These data support the use of rapid diagnostics in sepsis with concurrent Gram-negative bacteremia.

Performance of Daily Pads Containing Ophytrium and Chlorhexidine Digluconate 3% in Dogs With Local Cutaneous Bacterial and/or Malassezia Overgrowth

Local disturbances of the microbiota are common in dogs with underlying skin conditions. Antiseptic topical products are indicated to control such superficial disorders. The objective of this study was to evaluate the performance of a daily application of pads containing Ophytrium and chlorhexidine digluconate 3% (DOUXO® S3 PYO Pads, Ceva Santé Animale, France) in dogs with focal bacterial and/or Malassezia overgrowth. Eighteen dogs with focal skin dysbiosis were included in the analysis of this prospective, multicentric, field study. Dogs received daily pad applications for 14 days. Bacterial and/or Malassezia counts per microscopic field and a global score of the most affected patch (0-17 scale based on extension, severity, bacterial, and Malassezia cytological scores) were assessed by a veterinarian and pruritus by the owner (Pruritus Visual Analog Scale) on days (D)0, D7, D14. Owner and veterinarian evaluations for performance and satisfaction were recorded. Eleven dogs had primarily cocci overgrowth and seven mostly Malassezia. Mean bacterial and Malassezia counts decreased after 14 days (6.9-1.1; 7.6-1.5, respectively); 88.9% of dogs achieved a ≥70% microbial decrease and had ≤2 bacteria and ≤1 Malassezia per oil field. Mean global score of the most affected patch and pruritus score significantly improved at D14, respectively, from 8.6 to 2.6 and 4.5 to 1.2 (P < 0.05 each, mean improvements of 70.4 and 71.4%, respectively). Global veterinary assessment of the protocol was satisfactory, good, or excellent in 88.9% of cases. Most owners (94.4%) considered the protocol efficacious. Using a pad containing Ophytrium and chlorhexidine digluconate 3% daily for 14 days improved the skin condition and pruritus of dogs with local dysbiosis, resulting in high satisfaction levels for both veterinarians and dog owners.

Clinical Outcomes of Ceftriaxone vs Penicillin G for Complicated Viridans Group Streptococci Bacteremia

Background

Ceftriaxone (CTX) and penicillin G (PCN G) are considered reasonable treatment options for viridans group streptococci (VGS) bloodstream infections, but comparisons between these agents are limited. We evaluated clinical outcomes among patients treated with these agents for complicated VGS bacteremia.

Methods

This was a single-center retrospective study of adult patients with ≥1 positive VGS blood culture who were treated with either CTX or PCN G/ampicillin (both included in the PCN arm) between January 2013 and June 2019. The primary outcome was a composite of safety end points, including hospital readmission due to VGS bacteremia or adverse events (AEs) from therapy, Clostridioides difficile infections, treatment modification or discontinuation due to AEs from therapy, and development of extended-spectrum beta-lactamase resistance. Secondary outcomes included individual safety end points, VGS bacteremia recurrence, hospital readmission, and all-cause mortality.

Results

Of 328 patients screened, 94 met eligibility criteria (CTX n = 64, PCN n = 30). Streptococcus mitis was the most common isolate, and infective endocarditis was the predominant source of infection. CTX was not significantly associated with increased risk of the primary composite safety outcome (CTX 14% vs PCN 27%; P = .139). The driver of the composite outcome was hospital readmission due to VGS bacteremia or therapy complications. No secondary end points differed significantly between groups. On multivariate analysis, source removal was a protective factor of the primary composite safety outcome.

Conclusions

Despite potential safety concerns with the prolonged use of CTX in complicated VGS bacteremia, this study did not demonstrate higher rates of treatment failure, adverse events, or resistance.

Antimicrobial resistance: more than 70 years of war between humans and bacteria

Development of antibiotic resistance in bacteria is one of the major issues in the present world and one of the greatest threats faced by mankind. Resistance is spread through both vertical gene transfer (parent to offspring) as well as by horizontal gene transfer like transformation, transduction and conjugation. The main mechanisms of resistance are limiting uptake of a drug, modification of a drug target, inactivation of a drug, and active efflux of a drug. The highest quantities of antibiotic concentrations are usually found in areas with strong anthropogenic pressures, for example medical source (e.g., hospitals) effluents, pharmaceutical industries, wastewater influents, soils treated with manure, animal husbandry and aquaculture (where antibiotics are generally used as in-feed preparations). Hence, the strong selective pressure applied by antimicrobial use has forced microorganisms to evolve for survival. The guts of animals and humans, wastewater treatment plants, hospital and community effluents, animal husbandry and aquaculture runoffs have been designated as "hotspots for AMR genes" because the high density of bacteria, phages, and plasmids in these settings allows significant genetic exchange and recombination. Evidence from the literature suggests that the knowledge of antibiotic resistance in the population is still scarce. Tackling antimicrobial resistance requires a wide range of strategies, for example, more research in antibiotic production, the need of educating patients and the general public, as well as developing alternatives to antibiotics (briefly discussed in the conclusions of this article).

N-terminal Myristoylation Enhanced the Antimicrobial Activity of Antimicrobial Peptide PMAP-36PW

Drug-resistant bacteria infections and drug residues have been increasing and causing antibiotic resistance and public health threats worldwide. Antimicrobial peptides (AMPs) are novel antimicrobial drugs with the potential to solve these problems. Here, a peptide based on our previously studied peptide PMAP-36PW was designed via N-terminal myristoylation and referred to as Myr-36PW. The fatty acid modification provided the as-prepared peptide with good stability and higher antimicrobial activity compared with PMAP-36PW in vitro. Moreover, Myr-36PW exhibited effective anti-biofilm activity against Gram-negative bacteria and may kill bacteria by improving the permeability of their membranes. In addition, the designed peptide Myr-36PW could inhibit the bacterial growth of Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa GIM 1.551 to target organs, decrease the inflammatory damage, show an impressive therapeutic effect on mouse pneumonia and peritonitis experiments, and promote abscess reduction and wound healing in infected mice. These results reveal that Myr-36PW is a promising antimicrobial agent against bacterial infections.

High Primary Antibiotic Resistance of Helicobacter pylori Strains Isolated from Pediatric and Adult Patients in Poland during 2016-2018

Monitoring the antibiotic resistance of H. pylori is an important step in the effective treatment of this bacterium, thus the aim of the present study was to assess the prevalence of antimicrobial resistance of H. pylori strains isolated from pediatric and adult patients with primary infections in 2016–2018. Antral biopsies from 334 treatment-naïve patients (126 children and 208 adults) were obtained. A total of 71 clinical H. pylori strains (22 from children and 49 from adults) were isolated and examined for amoxicillin (AMX), clarithromycin (CLR), metronidazole (MTZ), tetracycline (TET), and levofloxacin (LEV) susceptibility. The activity of the antibiotics was measured by E-tests. Strains were considered as resistant to antibiotics with minimum inhibitory concentrations (MICs) equal to ≥0.125 μg/mL (AMX), ≥0.5 μg/mL (CLR), ≥8 μg/mL (MTZ), and ≥1 μg/mL (TET and LEV). The highest prevalence of antibiotic resistance in H. pylori strains was observed for CLR and MTZ, at frequencies of 54.5% and 31.8% vs. 30.6% and 46.9% for children and adults, respectively. A much lower frequency of isolation of resistant strains was demonstrated for LEV and TET, this being 9.1% and 4.5% vs. 18.4% and 4.1% for pediatric and adult patients, respectively. The presence of AMX-resistant strains was not observed. The H. pylori strains isolated from Polish patients with primary infections showed a high level of antibiotic resistance to CLR and MTZ (>30%).

Defeating Antibiotic-Resistant Bacteria: Exploring Alternative Therapies for a Post-Antibiotic Era

Antibiotics are one of the greatest medical advances of the 20th century, however, they are quickly becoming useless due to antibiotic resistance that has been augmented by poor antibiotic stewardship and a void in novel antibiotic discovery. Few novel classes of antibiotics have been discovered since 1960, and the pipeline of antibiotics under development is limited. We therefore are heading for a post-antibiotic era in which common infections become untreatable and once again deadly. There is thus an emergent need for both novel classes of antibiotics and novel approaches to treatment, including the repurposing of existing drugs or preclinical compounds and expanded implementation of combination therapies. In this review, we highlight to utilize alternative drug targets/therapies such as combinational therapy, anti-regulator, anti-signal transduction, anti-virulence, anti-toxin, engineered bacteriophages, and microbiome, to defeat antibiotic-resistant bacteria.