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BMC Microbiology Jul 2024Klebsiella aerogenes is an opportunistic pathogen that causes a wide variety of infections. Due to the rising problem of antibiotic resistance, novel antibiotics and...
BACKGROUND
Klebsiella aerogenes is an opportunistic pathogen that causes a wide variety of infections. Due to the rising problem of antibiotic resistance, novel antibiotics and strategies to combat bacterial infections are needed. Host-specific bacteriophages are natural enemies of bacteria and can be used in phage therapy as an alternative form of treatment against bacterial infections. Jumbo phages are defined as phages with genomes larger than 200 kb. Relatively few studies have been done on jumbo phages compared to smaller phages.
RESULTS
A novel phage, fENko-Kae01, was isolated from a commercial phage cocktail. Genomic analysis revealed that fENko-Kae01 is a lytic jumbo phage with a 360 kb genome encoding 578 predicted genes. No highly similar phage genomes were identified and fENko-Kae01 may be a completely new genus representative. No known genes associated with lysogenic life cycle, bacterial virulence, or antibiotic resistance were identified. The phage had myovirus morphology and a narrow host range. Phage resistant bacterial mutants emerged under phage selection. Whole genome sequencing revealed that the biogenesis of the flagellum was affected in four mutants and the lack of functional flagellum was confirmed in motility assays. Furthermore, phage fENKo-Kae01 failed to adsorb on the non-motile mutants indicating that the bacterial flagellum is the phage-binding receptor.
CONCLUSIONS
fENko-Kae01 is a novel jumbo bacteriophage that is considered safe for phage therapy. fENko-Kae01 uses the flagellum as the phage-binding receptor and may represent a completely novel genus.
Topics: Bacteriophages; Genome, Viral; Flagella; Enterobacter aerogenes; Host Specificity; Whole Genome Sequencing; Myoviridae
PubMed: 38951769
DOI: 10.1186/s12866-024-03387-1 -
Nature Communications Jul 2024An international collection of Staphylococcus aureus of clonal complex (CC) 398 from diverse hosts spanning all continents and a 30 year-period is studied based on...
An international collection of Staphylococcus aureus of clonal complex (CC) 398 from diverse hosts spanning all continents and a 30 year-period is studied based on whole-genome sequencing (WGS) data. The collection consists of publicly available genomic data from 2994 strains and 134 recently sequenced Swiss methicillin-resistant S. aureus (MRSA) CC398 strains. A time-calibrated phylogeny reveals the presence of distinct phylogroups present in Asia, North and South America and Europe. European MRSA diverged from methicillin-susceptible S. aureus (MSSA) at the beginning of the 1950s. Two major European phylogroups (EP4 and EP5), which diverged approximately 1974, are the main drivers of MRSA CC398 spread in Europe. Within EP5, an emergent MRSA lineage spreading among the European horse population (EP5-Leq) diverged approximately 1996 from the pig lineage (EP5-Lpg), and also contains human-related strains. EP5-Leq is characterized by staphylococcal cassette chromosome mec (SCCmec) IVa and spa type t011 (CC398-IVa-t011), and EP5-Lpg by CC398-SCCmecVc-t011. The lineage-specific antibiotic resistance and virulence gene patterns are mostly mediated by the acquisition of mobile genetic elements like SCCmec, S. aureus Genomic Islands (SaGIs), prophages and transposons. Different combinations of virulence factors are present on S. aureus pathogenicity islands (SaPIs), and novel antimicrobial resistance gene containing elements are associated with certain lineages expanding in Europe. This WGS-based analysis reveals the actual evolutionary trajectory and epidemiological trend of the international MRSA CC398 population considering host, temporal, geographical and molecular factors. It provides a baseline for global WGS-based One-Health studies of adaptive evolution of MRSA CC398 as well as for local outbreak investigations.
Topics: Animals; Methicillin-Resistant Staphylococcus aureus; Staphylococcal Infections; Phylogeny; Humans; Whole Genome Sequencing; Europe; Horses; Staphylococcus aureus; Genome, Bacterial; Virulence Factors; Chromosomes, Bacterial; Evolution, Molecular; Swine
PubMed: 38951499
DOI: 10.1038/s41467-024-49644-9 -
Brazilian Journal of Microbiology :... Jul 2024The worldwide prevalence of antimicrobial resistance coupled with the unavailability of newer antibiotics, has brought the sharp focus back among the scientific...
The worldwide prevalence of antimicrobial resistance coupled with the unavailability of newer antibiotics, has brought the sharp focus back among the scientific community, towards the discovery of novel alternative therapeutics to tackle the menace. Consequently, in the current post-antibiotic era, 'Bacteriophage Therapy' has emerged as one of the most promising option to address this problem. Bacteriophages, actually discovered long back, has shown greater potential to kill various bacterial pathogens, including the resistant clinical ones. Some of the other advantages for the use of bacteriophage therapy to treat infectious diseases include, wider availability of these microorganisms in nature, host-specific action, absence of any significant side-effects in humans and most often also exhibiting a broader anti-bacterial potential. In the recent times, the potential of phage therapy has been demonstrated in various treatments, clinical trials and infection models across the globe, where even antibiotics have completely failed. To address the global threat of AMR, WHO and UN have jointly illustrated "One Health" approach, recently extending the context to bacteriophage therapy. Many pharmaceutical companies have also recently started employing bacteriophages for developing different kinds of formulations for catering to medical and other industries. It has even shown great effect as combinatorial therapy along with antibiotics, to treat or manage various critical antibiotic resistant clinical infections. This continuously expanding potential of the bacteriophages holds great promise in the future, in the fight against the rising threat of AMR globally.
PubMed: 38951476
DOI: 10.1007/s42770-024-01434-7 -
European Journal of Drug Metabolism and... Jul 2024Piperacillin/tazobactam is extensively used off-label to treat late-onset neonatal sepsis, but safety and pharmacokinetic data in this population are limited....
BACKGROUND AND OBJECTIVES
Piperacillin/tazobactam is extensively used off-label to treat late-onset neonatal sepsis, but safety and pharmacokinetic data in this population are limited. Additionally, the organic immaturity of the newborns contributes to a high piperacillin pharmacokinetic variability. This affects the clinical efficacy of the antibiotic treatment and increases the probability of developing drug resistance. This study aimed to evaluate the predictive performance of reported piperacillin population pharmacokinetic models for their application in a model-informed precision dosing strategy in preterm and term Mexican neonatal intensive care patients.
METHODS
Published population pharmacokinetic models for piperacillin which included neonates in their study population were identified. From the reference models, structured models, population pharmacokinetic parameters, and interindividual and residual variability data were extracted to be replicated in pharmacokinetic software (NONMEM version 7.4). For the clinical study, a sampling schedule was designed, and 2-3 blood samples of 250 µL were taken from neonates who met the inclusion criteria. Piperacillin plasma concentrations were determined by liquid chromatography/tandem mass spectrometry. The clinical treatment data were collected, and piperacillin plasma concentrations were estimated using reference pharmacokinetic models for an a priori or Bayesian approach. Statistical methods were used in terms of bias and precision to evaluate the differences between observed and estimated neonatal piperacillin plasma concentrations with the different approaches and to identify the pharmacokinetic model that best fits the neonatal data.
RESULTS
A total of 70 plasma samples were collected from 25 neonatal patients, of which 15 were preterm neonates. The overall median value (range) postnatal age, gestational age, body weight, and serum creatinine at the sampling collecting day were 12 (3-26) days, 34.2 (26-41.1) weeks, 1.78 (0.08-3.90) Kg, 0.47 (0.20-0.90) mg/dL, respectively. Three population pharmacokinetic models for piperacillin in infants up to 2 months were identified, and their predictive performance in neonatal data was evaluated. No pharmacokinetic model was suitable for our population using an a priori approach. The model published by Cohen-Wolkowiez et al. in 2014 with a Bayesian approach showed the best performance of the pharmacokinetic models evaluated in our neonatal data. The procedure requires two blood samples (predose and postdose), and, when applied, it predicted 66.6% of the observations with a relative median absolute predicted error of less than 30%.
CONCLUSIONS
The population pharmacokinetic model developed by Cohen-Wolkowiez et al. in 2014 demonstrated superior performance in predicting the plasma concentration of piperacillin in preterm and term Mexican neonatal intensive care patients. The Bayesian approach, including two different piperacillin plasma concentrations, was clinically acceptable regarding bias and precision. Its application for model-informed precision dosing can be an option to optimize the piperacillin dosage in our population.
PubMed: 38951408
DOI: 10.1007/s13318-024-00906-3 -
Plant Foods For Human Nutrition... Jul 2024Phyllanthus emblica L. (syn. Emblica officinalis) fruits have been traditionally exploited to enhance the immune system and provide protection against bacterial and...
Phyllanthus emblica L. (syn. Emblica officinalis) fruits have been traditionally exploited to enhance the immune system and provide protection against bacterial and fungal diseases. The present study aimed to evaluate the synergistic interactions between chloramphenicol and several phenolic compounds found in P. emblica fruits against bacterial strains. The combination of P. emblica fruit extracts and its phenolic compounds demonstrated synergistic antibacterial activity when used in conjunction with chloramphenicol against both Gram-positive and Gram-negative bacteria. The combination of MIC with ½MIC exhibited a significant increase in bioactivity, with a 333.33-fold enhancement against B. subtilis. Similarly, the combination of MIC with 2MIC displayed a bioactivity enhancement of 16.02 folds against S. aureus. The co-administration of ½MIC and ½MIC resulted in a significant 35.71-fold increase in bioactivity against P. aeruginosa. Similarly, the combination of MIC and ½MIC exhibited a remarkable 166.66-fold enhancement in bioactivity against E. coli. The combinations of 2MIC and ½MIC, as well as ½MIC and ½MIC demonstrated the highest bioactivity enhancement of 17.85 folds for K. pneumoniae. This study claimed that the fruit extracts of P. emblica and its phenolic compounds could be utilized to augment the effectiveness of conventional antibiotics, which have acquired resistance to bacterial infections.
PubMed: 38951374
DOI: 10.1007/s11130-024-01206-6 -
Communications Biology Jul 2024Colistin remains an important antibiotic for the therapeutic management of drug-resistant Klebsiella pneumoniae. Despite the numerous reports of colistin resistance in...
Colistin remains an important antibiotic for the therapeutic management of drug-resistant Klebsiella pneumoniae. Despite the numerous reports of colistin resistance in clinical strains, it remains unclear exactly when and how different mutational events arise resulting in reduced colistin susceptibility. Using a bioreactor model of infection, we modelled the emergence of colistin resistance in a susceptible isolate of K. pneumoniae. Genotypic, phenotypic and mathematical analyses of the antibiotic-challenged and un-challenged population indicates that after an initial decline, the population recovers within 24 h due to a small number of "founder cells" which have single point mutations mainly in the regulatory genes encoding crrB and pmrB that when mutated results in up to 100-fold reduction in colistin susceptibility. Our work underlines the rapid development of colistin resistance during treatment or exposure of susceptible K. pneumoniae infections having implications for the use of cationic antimicrobial peptides as a monotherapy.
Topics: Klebsiella pneumoniae; Colistin; Anti-Bacterial Agents; Bioreactors; Drug Resistance, Bacterial; Klebsiella Infections; Microbial Sensitivity Tests; Humans
PubMed: 38951173
DOI: 10.1038/s42003-024-06378-0 -
The British Journal of General Practice... Jul 2024Despite the considerable morbidity caused by recurrent UTIs (rUTIs), and the wider personal and public health implications from frequent antibiotic use, few studies...
BACKGROUND
Despite the considerable morbidity caused by recurrent UTIs (rUTIs), and the wider personal and public health implications from frequent antibiotic use, few studies adequately describe the prevalence and characteristics of women with rUTIs or those who use prophylactic antibiotics.
AIM
To describe the prevalence, characteristics, and urine profiles of women with rUTIs with and without prophylactic antibiotic use in Welsh primary care.
DESIGN AND SETTING
Retrospective cross-sectional study in Welsh General Practice using the SAIL Databank.
METHOD
We describe the characteristics of women aged ≥18 years with rUTIs or using prophylactic antibiotics from 2010-2020, and associated urine culture results from 2015 - 2020.
RESULTS
6.0% of women (n=92,213) had rUTIs, and 1.7% (n=26,862) were prescribed prophylactic antibiotics. Only 49% of prophylactic antibiotic users met the definition of rUTIs before initiation. 81% of women with rUTIs had a urine culture result in the preceding 12 months with high rates of resistance to trimethoprim and amoxicillin. 64% of women taking prophylactic antibiotics had a urine culture result before initiation, and 18% (n=320) of women prescribed trimethoprim had resistance to it on the antecedent sample.
CONCLUSION
A substantial proportion of women had rUTIs or incident prophylactic antibiotic use. However, 64% of women had urine cultured before starting prophylaxis. There was a high proportion of cultured bacteria resistant to two antibiotics used for rUTI prevention and evidence of resistance to the prescribed antibiotic. More frequent urine cultures for rUTI diagnosis and before prophylactic antibiotic initiation could better inform antibiotic choices.
PubMed: 38950943
DOI: 10.3399/BJGP.2024.0015 -
Environmental Research Jun 2024The rapid increase of mcr-positive Klebsiella pneumoniae (K. pneumoniae) has received considerable attention and poses a major public health concern. Here, we... (Review)
Review
The rapid increase of mcr-positive Klebsiella pneumoniae (K. pneumoniae) has received considerable attention and poses a major public health concern. Here, we systematically analyzed the global distribution of mcr-positive K. pneumoniae isolates based on published articles as well as publicly available genomes. Combining strain information from 78 articles and 673 K. pneumoniae genomes, a total of 1000 mcr-positive K. pneumoniae isolates were identified. We found that mcr-positive K. pneumoniae has disseminated widely worldwide, especially in Asia, with a higher diversity of sequence types (STs). These isolates were disseminated in 57 countries and were associated with 12 different hosts. Most of the isolates were found in China and were isolated from human sources. Moreover, MLST analysis showed that ST15 and ST11 accounted for the majority of mcr-positive K. pneumoniae, which deserve sustained attention in further surveillance programs. mcr-1 and mcr-9 were the dominant mcr variants in mcr-positive K. pneumoniae. Furthermore, a Genome-wide association study (GWAS) demonstrated that mcr-1- and mcr-9-producing genomes exhibited different antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs), thereby indicating a distinct evolutionary path. Notably, the phylogenetic analysis suggested that certain mcr-positive K. pneumoniae genomes from various geographical areas and hosts harbored a high degree of genetic similarities (<20 SNPs), suggesting frequent cross-region and cross-host clonal transmission. Overall, our results emphasize the significance of monitoring and exploring the transmission and evolution of mcr-positive K. pneumoniae in the context of "One health".
PubMed: 38950813
DOI: 10.1016/j.envres.2024.119516 -
Environment International Jun 2024Multidrug-resistant bacteria and multi-resistance genes in sludge have become a serious issue for public health. It is imperative to develop feasible and environmentally...
Multidrug-resistant bacteria and multi-resistance genes in sludge have become a serious issue for public health. It is imperative to develop feasible and environmentally friendly methods of sludge composting to alleviate multidrug resistance genes. Plant-derived essential oil is an effective natural and eco-friendly antibacterial, which has great utilization in inhibiting pathogens in the agricultural industry. Nevertheless, the application of plant-derived essential oil to control pathogenic bacteria and antibiotic resistance in composting has not been reported. This study conducted a composting system by adding plant-derived essential oil i.e., oregano essential oil (OEO), to sludge composting. The findings indicated that multidrug resistance genes and priority pathogens (critical, high, and medium categories) were reduced by (17.0 ± 2.2)% and (26.5 ± 3.0)% in the addition of OEO (OH treatment) compared to control. Besides, the OH treatment changed the bacterial community and enhanced the gene sequences related to carbohydrate metabolism in compost microorganisms. Mantel test and variation partitioning analysis revealed that the target virulence factors (VFs), target mobile genetic elements (MGEs), and priority pathogens were the most important factors affecting multidrug resistance in composting. The OH treatment could significantly inhibit the target VFs, target MGEs, and priority pathogens, which were helpful for the suppression and elimination of multidrug resistance genes. These findings provide new insights into the regulation of multidrug resistance genes during sludge composting and a novel way to diminish the environmental risk of antibiotic resistance.
PubMed: 38950496
DOI: 10.1016/j.envint.2024.108854 -
Microbial Drug Resistance (Larchmont,... Jul 2024Little is known about the characteristics of uropathogenic (UPEC) associated with recurrent urinary tract infections (RUTIs). The present study aimed to analyze the...
Little is known about the characteristics of uropathogenic (UPEC) associated with recurrent urinary tract infections (RUTIs). The present study aimed to analyze the phenotypic antimicrobial resistance of recurrent UPEC isolates attributable to either relapse or reinfection. A total of 140 strains were isolated from 70 outpatients with RUTIs. All isolates were analyzed by random amplified polymorphic DNA-polymerase chain reaction to evaluate genetic similarity between the first and second isolates. We found that 64.2% (45/70) of outpatients had a relapse with the primary infecting strain and 35.7% (25/70) had reinfection with a new strain. Compared with reinfecting strains, relapse UPEC isolates exhibited much higher antimicrobial resistance; 89% of these isolates were multidrug-resistant and 46.6% were extended-spectrum β-lactamase producers. Our study provides evidence that RUTIs are mainly driven by the persistence of the original strain in the host (relapses) despite appropriate antibiotic treatments, and only RUTIs attributed to relapses seem to favor multidrug resistance in UPEC isolates.
PubMed: 38949898
DOI: 10.1089/mdr.2023.0177