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1.
J Med Microbiol ; 71(4)2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35476672

RESUMO

Introduction. Fosfomycin has retained activity against many multi-drug resistant (MDR) Gram-negatives, and may be useful against extended spectrum beta-lactamase (ESBL) producing and carbapenem-resistant Enterobacterales to improve clinical outcomes.Hypothesis/Gap Statement. There are few data from the UK on the susceptibility of invasive Gram-negative isolates to fosfomycin, especially in the era of increasing use of oral fosfomycin for urinary tract infections (UTIs).Aim. We evaluated fosfomycin susceptibility against 100 consecutive Gram-negative bloodstream isolates, both individually, and in combination with other mechanistically similar and differing antibiotics. The aim was to investigate the synergy between antibiotic combinations against several E. coli, K. pneumoniae and P. aeruginosa isolates with variable levels of resistance.Methodology. Disc diffusion and MIC test strip methods applying revised EUCAST guidelines for Fosfomycin were used, followed by the MTS™ 'cross synergy' method for 'resistant' isolates as defined below: (a) Fosfomycin resistant by MIC test strip; (b) MDR isolates defined as being resistant to ≥3 classes of antibiotics (based on routine sensitivity testing; beta lactams were considered as a single class), and/or (c) AMP C or ESBL or carbapenemase producers (or carbapenem resistant). FIC Index (Fractional Inhibitory Concentration Index) calculations were used to interpret findings, whereby: FIC = (MICA combination A+B/ MIC agent A) + (MICB combination A+B/ MIC agent B). A result of ≤0.5 was taken to indicate 'synergy', >0.5 and ≤1.0 to indicate 'additive' effect, >1.0 and ≤4.0 to indicate 'indifference', and >4.0 to indicate 'antagonism'.Results. We found that 95/100 isolates were susceptible to fosfomycin by MIC test strip, with 88/100 isolates susceptible to fosfomycin by disc, based on EUCAST guideline breakpoints. A total of 30/100 isolates (the more 'resistant' of the 100) were eligible for synergy testing according to our definitions (see Methodology), with the remaining 70 isolates not tested further. Seventeen out of 30 were MDR, 2/30 were AMP C producers and 9/30 were ESBL producers. Overall, 34/300 (11 %) of all combination tests showed synergy and 161/300 (54 %) were additive. Synergy was most commonly detected between fosfomycin and beta-lactam antibiotics, including piperacillin/tazobactam (10/30; 33 %), ceftazidime/avibactam (10/30; 30 %), and temocillin (8/30; 27 %). An additive effect was most commonly detected with aztreonam (25/30; 83 %) and meropenem (25/30; 83 %), but 100 % indifference was found with tigecycline (30/30). No antagonism was identified with any antibiotic combination.Conclusion. Fosfomycin non-susceptibility by MIC test strip was unusual. Synergy was variable when combining fosfomycin with other antibiotics against the more 'resistant' isolates. Synergistic/additive effects were detected for beta-lactam/fosfomycin combinations in >80 % of all such combinations, suggesting beta-lactams may be the preferred partner for fosfomycin. Agents with a discordant site of action were more likely to result in indifference. Antagonism was not detected.


Assuntos
Fosfomicina , Sepse , Monofosfato de Adenosina/farmacologia , Antibacterianos/farmacologia , Carbapenêmicos/farmacologia , Sinergismo Farmacológico , Escherichia coli , Fosfomicina/farmacologia , Hospitais de Ensino , Humanos , Klebsiella pneumoniae , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa , Reino Unido
2.
World J Microbiol Biotechnol ; 38(6): 102, 2022 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-35486219

RESUMO

Antibiotic resistance represents the main challenge of Helicobacter pylori infection worldwide. This study investigates the potential bactericidal effects of fosfomycin combinations with clarithromycin, metronidazole, ciprofloxacin, amoxicillin, rifampicin, and doxycycline against thirty-six H. pylori strains using the checkerboard and time-kill assay methods. The results showed that ≥ 50% of the strains were resistant to the six antibiotics. Remarkably, only six strains exerted resistance to these antibiotics, with the minimum inhibitory concentrations (MICs) ranges of (3.2-12.8 mg/l), (32-256 mg/l), (3.2-51.2 mg/l), (3.2-25.6 mg/l), (1.6-3.2 mg/l), and (25.6 > 51.2 mg/l), respectively. The seven antibiotics were evaluated through in silico studies for their permeability and ability to bind UDP-N-acetylglucosamine1-carboxyvinyltransferase (MurA) of H. pylori. The results indicated that fosfomycin exhibited the highest predicted membrane permeability (membrane ∆G insert = - 37.54 kcal/mol) and binding affinity (docking score = - 5.310 kcal/mol) for H. pylori MurA, compared to other tested antibiotics. The combinations of fosfomycin with these antibiotics exerted synergistic interactions (Fractional inhibitory concentration, FIC index < 1) against the six strains. Importantly, the combinations of fosfomycin with clarithromycin, doxycycline and rifampicin achieved bactericidal effects (reduction ≥ 3.0 Log10 cfu/ml) against the most resistant H. pylori strain. Notably, these effects increased with presence of metronidazole, which enhanced the activity of the fosfomycin combination with amoxicillin from a weak inhibition to bactericidal effect. This study provides evidence that the combination of fosfomycin with either clarithromycin, amoxicillin, doxycycline, or rifampicin (especially with the presence of metronidazole) could be a promising option for treating MDR H. pylori infection.


Assuntos
Fosfomicina , Infecções por Helicobacter , Helicobacter pylori , Amoxicilina/farmacologia , Antibacterianos/farmacologia , Claritromicina/farmacologia , Doxiciclina/farmacologia , Fosfomicina/farmacologia , Infecções por Helicobacter/tratamento farmacológico , Humanos , Metronidazol/farmacologia , Rifampina/farmacologia
3.
Int. j. antimicrob. agents ; Mar.2022. graf, tab
Artigo em Inglês | Sec. Est. Saúde SP, Sec. Est. Saúde SP, CONASS, SESSP-IDPCPROD, Sec. Est. Saúde SP | ID: biblio-1362633

RESUMO

Abstract Determining the role of the immune response in preventing antimicrobial resistance and optimizing antibiotic regimens against carbapenemase-producing Klebsiella pneumoniae (KPC) is a research gap that exists and needs to be further explored. The objective of this study was to determine the pharmacodynamics and immunomodulatory effects of fosfomycin alone and in combination with polymyxin B against KPC-2-producing K. pneumoniae clinical isolates. Six K. pneumoniae isolates were selected (polymyxin B_MIC: 0.5-64 mg/L; Fosfomycin MIC: 16-128 mg/L) to evaluate the pharmacodynamics of mono- and combination therapies in static time-kill studies. A mechanism based model was used to characterize the joint activity of polymyxin B and fosfomycin. A549 human airway epithelial cells were infected with four isolates to evaluate the immunomodulatory effects of treatment. Our mechanism-based model indicated greater bacterial killing efficacy of fosfomycin with polymyxin B compared to monotherapy. In combination, polymyxin B was assumed to exert an outer membrane effect which resulted in an increase in fosfomycin's ability to reach its target site. The mechanism based model described the data well across all six strains with R2 values ranging from 0.705 to 0.935. The combination reduced K. pneumoniae-induced IL-6 and IL-8 but not TNF-α expression. The reduction in cytokine expression was greater with polymyxin B than fosfomycin alone, and combinations showed significantly greater reductions compared to monotherapies. Our findings suggest that further research is needed to understand immune-mediated killing to identify a strategy which harnesses the power of the immune response against these hard to treat bacteria in an in vivo system.


Assuntos
Fosfomicina , Klebsiella pneumoniae , Polimixina B
4.
J Antimicrob Chemother ; 77(5): 1286-1295, 2022 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-35296898

RESUMO

OBJECTIVES: To investigate the prevalence and molecular characteristics of fosA3 and fosA7 among Salmonella isolates. METHODS: Five hundred and fifty-one Salmonella isolates collected from food animals in China during 2016-19 were screened for fos genes. The drug resistance, serovars, clonal relationships and genetic environments of fosA were compared between fosA7- and fosA3-positive Salmonella. RESULTS: A relatively high prevalence of fosA7 (9.26%) and fosA3 (6.53%) was identified. fosA3 was associated with high-level fosfomycin resistance (≥512 mg/L), while fosA7 conferred relatively low-level resistance that was independent of the presence of glucose-6-phosphate. Additionally, fosA7 could facilitate Salmonella survival under oxidative stress. Both fosA3 and fosA7 were found in diverse serovars and STs, but segregated into distinct groups. The fosA3-positive Salmonella Typhimurium/Salmonella Indiana strains showed close genetic relationships, while fosA7-positive Salmonella Meleagridis/Salmonella Agona/Salmonella Derby showed a relatively high degree of whole-genome sequence heterogeneity. fosA3 was located on conjugative IncHI2 plasmids or chromosomes, while fosA7 was strictly chromosomal. Furthermore, two strains carried large chromosomal fosA7 regions within genomic islands. The fosA3 and fosA7 contigs from our isolates and the NCBI could be segregated into four primary and distinct genomic backbones. IS26 and the antibiotic resistance genes (ARGs) blaCTX-M, blaTEM-1B and rmtB were frequently adjacent to fosA3, while fosA7-carrying contigs generally lacked mobile elements and ARGs. CONCLUSIONS: fosA3 and fosA7 were the primary factors contributing to reduced fosfomycin susceptibility, to different degrees, in these Salmonella isolates. The distinct distributions and molecular characteristics of fosA7 and fosA3 indicated that their origin and evolution in Salmonella were most likely distinct.


Assuntos
Fosfomicina , Animais , Antibacterianos/farmacologia , China/epidemiologia , Escherichia coli/genética , Testes de Sensibilidade Microbiana , Plasmídeos , Prevalência , Salmonella/genética , beta-Lactamases/genética
5.
Emerg Microbes Infect ; 11(1): 1166-1173, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35332834

RESUMO

Fosfomycin has gained attention as a combination therapy for methicillin-resistant Staphylococcus aureus infections. Hence, the detection of novel fosfomycin-resistance mechanisms in S. aureus is important. Here, the minimal inhibitory concentrations (MICs) of fosfomycin in CC1 methicillin-resistant S. aureus were determined. The pangenome analysis and comparative genomics were used to analyse CC1 MRSA. The gene function was confirmed by cloning the gene into pTXΔ. A phylogenetic tree was constructed to determine the clustering of the CC1 strains of S. aureus. We identified a novel gene, designated fosY, that confers fosfomycin resistance in S. aureus. The FosY protein is a putative bacillithiol transferase enzyme sharing 65.9-77.5% amino acid identity with FosB and FosD, respectively. The function of fosY in decreasing fosfomycin susceptibility was confirmed by cloning it into pTXΔ. The pTX-fosY transformant exhibited a 16-fold increase in fosfomycin MIC. The bioinformatic analysis showed that fosY is in a novel genomic island designated RIfosY (for "resistance island carrying fosY") that originated from other species. The global phylogenetic tree of ST1 MRSA displayed this fosY-positive ST1 clone, originating from different regions, in the same clade. The novel resistance gene in the fos family, fosY, and a genomic island, RIfosY, can promote cross-species gene transfer and confer resistance to CC1 MRSA causing the failure of clinical treatment. This emphasises the importance of genetic surveillance of resistance genes among MRSA isolates.


Assuntos
Fosfomicina , Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Fosfomicina/farmacologia , Ilhas Genômicas , Humanos , Testes de Sensibilidade Microbiana , Filogenia , Infecções Estafilocócicas/epidemiologia , Staphylococcus aureus
6.
Microbiol Spectr ; 10(2): e0250421, 2022 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-35352940

RESUMO

The reference standard for fosfomycin antimicrobial susceptibility testing (AST) is agar dilution, but it is laborious and is not routinely used in diagnostic microbiology. In this study, we evaluated the performance of a ready-to-use commercially available agar dilution kit for fosfomycin AST (Liofilchem Diagnostics). We compared this kit with the reference standard agar dilution, performed according to the Clinical & Laboratory Standards Institute (CLSI) in 229 clinical isolates. The isolates were selected to represent both Gram-positive and Gram-negative microorganisms, with various MIC values. It consisted of 43 enterococci (E. faecalis n = 16, E. faecium n = 27), 13 methicillin-resistant S. aureus (MRSA), 118 Enterobacterales (Escherichia coli n = 94, Klebsiella pneumoniae n = 20, and Enterobacter cloacae complex n = 4), 55 Pseudomonas aeruginosa, and three ATCC isolates. Using CLSI breakpoints for enterococci for oral treatment of urinary tract infections, European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints for intravenous dosing for Enterobacterales and Staphylococci, and epidemiological cutoff value for P. aeruginosa, the essential agreement was 87.5%, and 99.6% after discrepancy resolution. There was no very major error, and 1.9% major error before, and 0.9% major error after resolution of discrepancies. The commercial test showed 100% reproducibility. In conclusion, in comparison to the reference standard, the ready-to-use commercially available agar dilution kit for fosfomycin AST showed excellent performance. IMPORTANCE Fosfomycin is increasingly needed to treat infection due to multidrug resistant microorganisms. Yet, the antimicrobial susceptibility test (AST) of fosfomycin is fraught with difficulties or often laborious to perform. An easy-to-use AST method for fosfomycin is thus needed. In this study, we showed that the ready-to-use commercially available agar dilution kit, in comparison to the reference standard, showed excellent performance.


Assuntos
Fosfomicina , Staphylococcus aureus Resistente à Meticilina , Ágar , Antibacterianos/farmacologia , Enterococcus , Escherichia coli , Fosfomicina/farmacologia , Testes de Sensibilidade Microbiana , Reprodutibilidade dos Testes
7.
Int J Antimicrob Agents ; 59(5): 106574, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35307561

RESUMO

Urinary tract infections (UTIs) are prevalent worldwide, particularly among women. Their incidence increases with age, and treatment is increasingly challenging owing to antibiotic resistance and the lack of new agents. We investigated the susceptibility of current urinary isolates to fosfomycin and other antibiotics across Europe. This cross-sectional study collected consecutive urinary isolates from non-hospitalised women at 20 centres in Belgium, the UK, Italy, Spain and Russia. Bacteria were tested by disk diffusion with relevant antibiotics. As a quality control, a central laboratory re-tested, by agar dilution, (i) isolates found resistant to fosfomycin and (ii) every tenth isolate; all non-Russian sites were included. A total of 2848 isolates were analysed, principally Escherichia coli (2064; 72.5%), Klebsiella spp. (275; 9.7%) and Proteus spp. (103; 3.6%). For E. coli, agents active against >90% of isolates were nitrofurantoin (98.5%), fosfomycin (96.4%) and mecillinam (91.8%). Fosfomycin and nitrofurantoin remained active against >90% of cephalosporin-resistant E. coli. Among 143 E. coli recorded as susceptible locally by disk tests, 138 (96.5%) were confirmed susceptible by minimum inhibitory concentration (MIC) tests, however resistance was only confirmed in 29/58 (50.0%) of those reported resistant by local disk tests. Escherichia coli was found to be the most common uropathogen isolated and was highly susceptible to fosfomycin, nitrofurantoin and mecillinam, all used effectively for more than 30 years. Guidelines advocating fosfomycin for uncomplicated UTIs in women remain microbiologically valid.


Assuntos
Infecções por Escherichia coli , Fosfomicina , Infecções Urinárias , Andinocilina/farmacologia , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Estudos Transversais , Escherichia coli , Infecções por Escherichia coli/tratamento farmacológico , Infecções por Escherichia coli/epidemiologia , Infecções por Escherichia coli/microbiologia , Feminino , Fosfomicina/farmacologia , Fosfomicina/uso terapêutico , Humanos , Masculino , Testes de Sensibilidade Microbiana , Nitrofurantoína/farmacologia , Infecções Urinárias/tratamento farmacológico , Infecções Urinárias/microbiologia
8.
Int J Antimicrob Agents ; 59(4): 106566, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35288260

RESUMO

Determining the role of the immune response in preventing antimicrobial resistance and optimising antibiotic regimens against carbapenemase-producing Klebsiella pneumoniae is a research gap that exists and needs to be further explored. The objective of this study was to determine the pharmacodynamic and immunomodulatory effects of fosfomycin alone and in combination with polymyxin B against KPC-2-producing K. pneumoniae clinical isolates. Six K. pneumoniae isolates were selected (polymyxin B MIC, 0.5-64 mg/L; fosfomycin MIC, 16-128 mg/L) to evaluate the pharmacodynamics of monotherapy and combination therapies in static time-kill studies. A mechanism-based model was used to characterise the joint activity of polymyxin B and fosfomycin. A549 human airway epithelial cells were infected with four isolates to evaluate the immunomodulatory effects of treatment. Our mechanism-based model indicated greater bacterial killing efficacy of fosfomycin with polymyxin B compared with monotherapy. In combination, polymyxin B was assumed to exert an outer membrane effect that resulted in an increase in the ability of fosfomycin to reach its target site. The mechanism-based model described the data well across all six strains, with R2 values ranging from 0.705-0.935. Combination therapy reduced K. pneumoniae-induced IL-6 and IL-8 but not TNFα expression. The reduction in cytokine expression was greater with polymyxin B than fosfomycin alone; combination therapy showed significantly greater reduction compared to either monotherapy. Our findings suggest that further research is needed to better understand immune-mediated killing in order to identify a strategy which harnesses the power of the immune response against these hard-to-treat bacteria.


Assuntos
Enterobacteriáceas Resistentes a Carbapenêmicos , Fosfomicina , Infecções por Klebsiella , Antibacterianos/uso terapêutico , Proteínas de Bactérias/metabolismo , Enterobacteriáceas Resistentes a Carbapenêmicos/metabolismo , Fosfomicina/farmacologia , Fosfomicina/uso terapêutico , Humanos , Imunidade , Infecções por Klebsiella/tratamento farmacológico , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae , Testes de Sensibilidade Microbiana , Polimixina B/farmacologia , Polimixina B/uso terapêutico , beta-Lactamases/metabolismo
9.
J Antimicrob Chemother ; 77(5): 1436-1443, 2022 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-35141753

RESUMO

OBJECTIVES: Synergistic combinations of daptomycin and ß-lactam antibiotics are currently recommended for treatment of VRE bloodstream infection (BSI). The efficacy of these combinations is jeopardized by VRE inherently resistant to ß-lactam antibiotics. The combination of daptomycin and fosfomycin is recommended as an alternative therapy for VRE BSI; however, clinical data to support use of this combination are lacking. PATIENTS AND METHODS: We conducted a prospective observational multicentre study of patients treated with a combination of daptomycin and fosfomycin for VRE BSI during 2016-20. The primary outcome was 28 day mortality. Multivariable logistic regression was performed for outcome analysis. RESULTS: The study included 106 patients from 1112 VRE BSI episodes. The overall 28 day mortality was 40.6%. The median (IQR) daptomycin dose was 10.18 mg/kg (9.43-10.70). The fosfomycin dose was 16 g/day (8-22.5). Ninety-six isolates were available for MIC testing. The fosfomycin MIC was 32 mg/L in 6 (6.3%), 64 mg/L in 68 (70.8%) and ≥128 mg/L in 22 (22.9%) isolates. Independent of Charlson comorbidity index and Pitt bacteraemia score, fosfomycin MIC ≥128 mg/L [adjusted OR (aOR) = 3.05; 95% CI = 1.01-9.19; P = 0.047] and daptomycin dose (aOR = 0.64; 95% CI = 0.43-0.97; P = 0.04) predicted mortality. CONCLUSIONS: Higher daptomycin dose and susceptibility to fosfomycin were independently associated with lower mortality in patients with VRE BSI. Our results suggest that higher doses of daptomycin are indicated for VRE BSI, whether or not it is used in combination with fosfomycin. The combination was less effective for patients with fosfomycin-resistant isolates.


Assuntos
Bacteriemia , Daptomicina , Enterococcus faecium , Fosfomicina , Infecções por Bactérias Gram-Positivas , Enterococos Resistentes à Vancomicina , Antibacterianos , Bacteriemia/tratamento farmacológico , Daptomicina/farmacologia , Daptomicina/uso terapêutico , Fosfomicina/farmacologia , Fosfomicina/uso terapêutico , Infecções por Bactérias Gram-Positivas/tratamento farmacológico , Humanos , Testes de Sensibilidade Microbiana , Monobactamas/farmacologia , Estudos Prospectivos , Vancomicina/farmacologia
10.
J Antimicrob Chemother ; 77(5): 1334-1343, 2022 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-35170719

RESUMO

BACKGROUND: Neonatal sepsis is a serious bacterial infection of neonates, globally killing up to 680 000 babies annually. It is frequently complicated by antimicrobial resistance, particularly in low- and middle-income country (LMIC) settings with widespread resistance to the WHO's recommended empirical regimen of ampicillin and gentamicin. OBJECTIVES: We assessed the utility of flomoxef and fosfomycin as a potential alternative empirical regimen for neonatal sepsis in these settings. METHODS: We studied the combination in a 16-arm dose-ranged hollow-fibre infection model (HFIM) experiment and chequerboard assays. We further assessed the combination using clinically relevant regimens in the HFIM with six Enterobacterales strains with a range of flomoxef/fosfomycin MICs. RESULTS: Pharmacokinetic/pharmacodynamic modelling of the HFIM experimental output, along with data from chequerboard assays, indicated synergy of this regimen in terms of bacterial killing and prevention of emergence of fosfomycin resistance. Flomoxef monotherapy was sufficient to kill 3/3 strains with flomoxef MICs ≤0.5 mg/L to sterility. Three of three strains with flomoxef MICs ≥8 mg/L were not killed by fosfomycin or flomoxef monotherapy; 2/3 of these were killed with the combination of the two agents. CONCLUSIONS: These data suggest that flomoxef/fosfomycin could be an efficacious and synergistic regimen for the empirical treatment of neonatal sepsis in LMIC settings with prevalent antimicrobial resistance. Our HFIM results warrant further assessment of the flomoxef/fosfomycin combination in clinical trials.


Assuntos
Fosfomicina , Sepse Neonatal , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Cefalosporinas , Farmacorresistência Bacteriana , Fosfomicina/farmacologia , Fosfomicina/uso terapêutico , Humanos , Recém-Nascido , Testes de Sensibilidade Microbiana , Sepse Neonatal/tratamento farmacológico
11.
J Antimicrob Chemother ; 77(5): 1324-1333, 2022 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-35211736

RESUMO

INTRODUCTION: The use of oral fosfomycin for urinary tract infections (UTIs) caused by non-Escherichia coli uropathogens is uncertain, including Klebsiella pneumoniae, the second most common uropathogen. METHODS: A multicompartment bladder infection in vitro model was used with standard media and synthetic human urine (SHU) to simulate urinary fosfomycin exposure after a single 3 g oral dose (fAUC0-72 16884 mg·h/L, t½ 5.5 h) against 15 K. pneumoniae isolates including ATCC 13883 (MIC 2 to >1024 mg/L) with a constant media inflow (20 mL/h) and 4-hourly voiding of each bladder. The impact of the media (CAMHB + G6P versus SHU) on fosfomycin MIC measurements, drug-free growth kinetics and regrowth after fosfomycin administration was assessed. A low and high starting inoculum (5.5 versus 7.5 log10 cfu/mL) was assessed in the bladder infection model. RESULTS: Compared with CAMHB, isolates in SHU had a slower growth rate doubling time (37.7 versus 24.1 min) and reduced growth capacity (9.0 ± 0.3 versus 9.4 ± 0.3 log10 cfu/mL), which was further restricted with increased inflow rate (40 mL/h) and more frequent voids (2-hourly). Regrowth was commonly observed in both media with emergence of fosfomycin resistance promoted by a high starting inoculum in CAMHB (MIC rise to ≥1024 mg/L in 13/14 isolates). Resistance was rarely detected in SHU, even with a high starting inoculum (MIC rise to ≥1024 mg/L in 2/14 isolates). CONCLUSIONS: Simulated in an in vitro UTI model, the regrowth of K. pneumoniae urinary isolates was inadequately suppressed following oral fosfomycin therapy. Efficacy was further reduced by a high starting inoculum.


Assuntos
Cistite , Fosfomicina , Infecções por Klebsiella , Infecções Urinárias , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Meios de Cultura , Cistite/tratamento farmacológico , Escherichia coli , Feminino , Humanos , Infecções por Klebsiella/tratamento farmacológico , Klebsiella pneumoniae , Masculino , Testes de Sensibilidade Microbiana , Bexiga Urinária , Infecções Urinárias/tratamento farmacológico
12.
Int J Mol Sci ; 23(3)2022 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-35163052

RESUMO

The rise of multidrug-resistant Gram-negative pathogens and the lack of novel antibiotics to address this problem has led to the rescue of old antibiotics without a relevant use, such as fosfomycin. Stenotrophomonas maltophilia is a Gram-negative, non-fermenter opportunistic pathogen that presents a characteristic low susceptibility to several antibiotics of common use. Previous work has shown that while the so-far described mechanisms of fosfomycin resistance in most bacteria consist of the inactivation of the target or the transporters of this antibiotic, as well as the production of antibiotic-inactivating enzymes, these mechanisms are not selected in S. maltophilia fosfomycin-resistant mutants. In this microorganism, fosfomycin resistance is caused by the inactivation of enzymes belonging to its central carbon metabolism, hence linking metabolism with antibiotic resistance. Consequently, it is relevant to determine how different growing conditions, including urine and synthetic sputum medium that resemble infection, could impact the evolutionary pathways towards fosfomycin resistance in S. maltophilia. Our results show that S. maltophilia is able to acquire high-level fosfomycin resistance under all tested conditions. However, although some of the genetic changes leading to resistance are common, there are specific mutations that are selected under each of the tested conditions. These results indicate that the pathways of S. maltophilia evolution can vary depending on the infection point and provide information for understanding in more detail the routes of fosfomycin resistance evolution in S. maltophilia.


Assuntos
Proteínas de Bactérias/genética , Farmacorresistência Bacteriana Múltipla , Fosfomicina/farmacologia , Stenotrophomonas maltophilia/crescimento & desenvolvimento , Adulto , Técnicas Bacteriológicas , Carbono/metabolismo , Evolução Molecular , Feminino , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Mutação , Stenotrophomonas maltophilia/efeitos dos fármacos , Stenotrophomonas maltophilia/genética
13.
J Phys Chem B ; 126(7): 1388-1403, 2022 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-35138863

RESUMO

Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen responsible for many nosocomial infections. It is quite resistant to various antibiotics, caused by the absence of general diffusion pores in the outer membrane. Instead, it contains many substrate-specific channels. Among them are the two phosphate- and pyrophosphate-specific porins OprP and OprO. Phosphonic acid antibiotics such as fosfomycin and fosmidomycin seem to be good candidates for using these channels to enter P. aeruginosa bacteria. Here, we investigated the permeation of fosfomycin through OprP and OprO using electrophysiology and molecular dynamics (MD) simulations. The results were compared to those of the fosmidomycin translocation, for which additional MD simulations were performed. In the electrophysiological approach, we noticed a higher binding affinity of fosfomycin than of fosmidomycin to OprP and OprO. In MD simulations, the ladder of arginine residues and the cluster of lysine residues play an important role in the permeation of fosfomycin through the OprP and OprO channels. Molecular details on the permeation of fosfomycin through OprP and OprO channels were derived from MD simulations and compared to those of fosmidomycin translocation. In summary, this study demonstrates that the selectivity of membrane channels can be employed to improve the permeation of antibiotics into Gram-negative bacteria and especially into resistant P. aeruginosa strains.


Assuntos
Fosfomicina , Pseudomonas aeruginosa , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Proteínas de Bactérias/química , Fosfomicina/metabolismo , Fosfatos/metabolismo , Porinas/química , Pseudomonas aeruginosa/química
14.
Biomed Res Int ; 2022: 8334153, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35141335

RESUMO

The understanding about virulence factors (VFs) and the drug resistance of uropathogenic Escherichia coli (UPEC) helps us understand the pathogenesis of urinary tract infections (UTIs) and make better decisions for clinical treatment. This study examined the correlation between the extended-spectrum ß-lactamases (ESBLs) phenotype and VFs in UPEC strains. In addition, we validated the therapeutic potential of fosfomycin in acute pyelonephritis mice. From May 2017 to November 2018, 22 nonduplicate E coli. strains were isolated from UTI patients. PCR was utilized to detect the distribution of virulence genes. We also analyzed the ESBL phenotype in E coli. We further evaluated the therapeutic effect of intravenous fosfomycin treatment in the acute pyelonephritis (APN) model. All 22 UPEC strains expressed the type 1 fimbriae (FimH) gene and more than 50% (12/22) of strains produced ESBLs. The detection rates of the iron acquisition-associated genes ChuT and IutA were 77.3% (n = 17) and 50% (n = 11) and those of P fimbria papA and papC genes were 45% (n = 10) and 50% (n = 11), respectively. Though the VFs were closely related with pathologenicity, the relationship between VFs and ESBLs still needs further investigation. Furthermore, intravenous fosfomycin 800 mg/kg significantly reduced the bacterial load and the inflammatory infiltration in the bladder and kidney, maintaining the structural integrity of the kidney. Intravenous fosfomycin administration can be used for the treatment of acute pyelonephritis caused by highly pathogenic and drug-resistant UPEC strains.


Assuntos
Infecções por Escherichia coli/tratamento farmacológico , Infecções por Escherichia coli/microbiologia , Fosfomicina/farmacologia , Pielonefrite/tratamento farmacológico , Pielonefrite/microbiologia , Escherichia coli Uropatogênica/patogenicidade , Animais , Modelos Animais de Doenças , Humanos , Camundongos , Testes de Sensibilidade Microbiana , Escherichia coli Uropatogênica/genética , Escherichia coli Uropatogênica/isolamento & purificação , Virulência/genética , beta-Lactamases
16.
Sci Total Environ ; 824: 153928, 2022 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-35182630

RESUMO

AIMS: The increasing number of globally established fosfomycin-resistant (FosR) Gram-negative bacteria inspired us to investigate the occurrence of FosREnterobacterales populations (esp. E. coli) in samples of city wastewater treatment plants (WWTPs) and hospital sewage in Hatay, Turkey. FosR target bacteria were further characterized for their clonal relatedness, resistomes and mobile genetic elements (MGEs) to evaluate their impact on fosfomycin resistance dissemination. METHODS: A total of 44 samples from raw and treated waters of WWTPs as well as of two hospitals in the Hatay province were subjected to selective cultivation for recovering FosREnterobacterales. The presence of fosA was verified by PCR and Sanger amplicon sequencing. Detected E. coli were further evaluated against antimicrobial susceptibility-testing, macrorestriction profiling (PFGE) and whole-genome sequencing (WGS). Bioinformatics analysis was performed for genome subtyping (i.e., MLST, serotype), resistome/virulome determination and dissection of the genetic determinants of plasmidic fosA3/4 resistances. RESULTS: Besides ten non-E. coli Enterobacterales, 29 E. coli were collected within this study. In silico-based subtyping revealed that E. coli isolates were assigned to six different serovars and 14 sequence types (ST), while O8:H21 and ST410 represented the major prevalent types, respectively. Fosfomycin resistance in the isolates was found to be mediated by the fosA4 (n = 18), fosA3 (n = 10) and fosA (n = 1), which are frequently associated with transmissible MGEs. Reconstruction of plasmid-associated fosA gene context revealed a linkage between the resistance cassette and IS6 (IS26 family) transposases, which might represent a major driver for the distribution of the genes and the generation of novel fosA-carrying plasmids. CONCLUSIONS: The occurrence of plasmid-mediated, transmissible FosR in E. coli from wastewater pose a foreseeable threat to "One-Health". To minimize further spread of the resistances in bacterial populations associated with environmental, animal and human health further resistance monitoring and management strategies must be developed.


Assuntos
Infecções por Escherichia coli , Fosfomicina , Animais , Antibacterianos/farmacologia , Farmacorresistência Bacteriana/genética , Escherichia coli , Infecções por Escherichia coli/epidemiologia , Hospitais , Sequências Repetitivas Dispersas , Testes de Sensibilidade Microbiana , Tipagem de Sequências Multilocus , Plasmídeos/genética , Turquia , Águas Residuárias , beta-Lactamases/genética
17.
Lancet Infect Dis ; 22(5): 706-717, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35065063

RESUMO

BACKGROUND: Neisseria gonorrhoeae causes gonorrhoea, a common sexually transmitted infection. Emerging strains resistant to first-line ceftriaxone threaten N gonorrhoeae management. Hence, alternative treatments are needed. We aimed to evaluate the efficacy of ertapenem, gentamicin, and fosfomycin as alternative treatments for anogenital N gonorrhoeae. METHODS: In a randomised, controlled, double-blind, non-inferiority trial (three experimental groups and one control group) at the Centre for Sexual Health in Amsterdam, Netherlands, we included adults aged 18 years or older, with anorectal or urogenital gonorrhoea. With random permuted blocks, participants were randomly assigned (1:1:1:1) to receive intramuscular 500 mg ceftriaxone (control group), intramuscular 1000 mg ertapenem, intramuscular 5 mg/kg gentamicin (maximum 400 mg), or oral 6 g fosfomycin. The primary outcome was the proportion of participants with a negative nucleic acid amplification test of the predefined primary infected site, 7-14 days after treatment. The primary analysis was per protocol (ie, excluding those lost to follow-up). The modified intention-to-treat analysis included all randomly assigned patients with anogenital gonorrhoea considering those lost-to-follow-up as treatment failure. Non-inferiority was established if the lower Hochberg-corrected 95% CI for difference between the experimental and control groups was greater than -10%. For the analysis of adverse events, we included all participants who received medication. The trial was registered at ClinicalTrials.gov (NCT03294395) and is complete. FINDINGS: Between Sept 18, 2017, and June 5, 2020, from 2160 patients invited to participate, we assigned 346 (16%) participants to receive either ceftriaxone (n=103), ertapenem (n=103), gentamicin (n=102), or fosfomycin (n=38). The fosfomycin group was terminated early after interim analysis revealed less than 60% efficacy. In the primary per-protocol analysis, 93 (100%) of 93 patients in the ceftriaxone group, 86 (99%) of 87 patients in the ertapenem group, 79 (93%) of 85 patients in the gentamicin group, and four (12%) of 33 patients in the fosfomycin group cleared N gonorrhoeae (risk difference vs ceftriaxone -0·01 [95% CI -0·08 to 0·05] for ertapenem and -0·07 [-0·16 to -0·01] for gentamicin). Thus, ertapenem proved non-inferior to ceftriaxone. In mITT analysis, risk differences versus ceftriaxone were -0·08 (-0·17 to 0·003) for ertapenem and -0·11 (-0·21 to -0·04) for gentamicin. We observed a higher proportion of patients with at least one adverse event in the ertapenem group (58 [56%] of 103) and fosfomycin group (36 [95%] of 38) versus the ceftriaxone group (24 [23%] of 103). INTERPRETATION: Single-dose 1000 mg ertapenem is non-inferior to single-dose 500 mg ceftriaxone in gonorrhoea treatment. Yet, 5 mg/kg gentamicin (maximum 400 mg) is not non-inferior to ceftriaxone. Ertapenem is a potential effective alternative for anogenital N gonorrhoeae infections and merits evaluation for ceftriaxone-resistant infections. FUNDING: ZonMw and GGD-Amsterdam. TRANSLATION: For the Dutch translation of the abstract see Supplementary Materials section.


Assuntos
Fosfomicina , Gonorreia , Adulto , Antibacterianos , Ceftriaxona , Ertapenem/farmacologia , Ertapenem/uso terapêutico , Fosfomicina/farmacologia , Fosfomicina/uso terapêutico , Gentamicinas/efeitos adversos , Gentamicinas/uso terapêutico , Gonorreia/tratamento farmacológico , Humanos , Neisseria gonorrhoeae , Resultado do Tratamento
18.
Antimicrob Agents Chemother ; 66(3): e0222721, 2022 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-35041510

RESUMO

In-silico analysis and cloning experiments identified a fosC2-like fosfomycin resistance gene in the chromosome of Aliidiomarina shirensis, with our data suggesting that this bacterium might be added to the list of species identified as reservoirs of fos-like genes that were subsequently acquired by other Gram-negative species. Indeed, the fosC2 gene was identified as acquired in Providencia huaxinensis and Aeromonas hydrophila isolates, with this gene being located in class 1 integron structures in the latter cases. Biochemical characterization and site-directed mutagenesis showed a higher catalytic efficiency for the intrinsic FosC2AS (from A. shirensis) than for the acquired FosC2 (from P. huaxinensis) enzyme due to a single substitution in the amino acid sequence (Gly43Glu). Notably, this study constitutes the first identification of the likely natural reservoir of a complete gene cassette (including its attC site).


Assuntos
Fosfomicina , Antibacterianos/farmacologia , Fosfomicina/farmacologia , Gammaproteobacteria , Integrons/genética , Testes de Sensibilidade Microbiana , Plasmídeos/genética , Reação em Cadeia da Polimerase
19.
Female Pelvic Med Reconstr Surg ; 28(2): 109-114, 2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-35084371

RESUMO

OBJECTIVES: The aim of this study was to evaluate the role of oral fosfomycin to prevent the use of intravenous (IV) antibiotic therapy in women with recurrent urinary tract infection (RUTI) complicated by antibiotic allergies and/or multidrug-resistant organisms. METHODS: After institutional review board approval, a retrospective review of women prescribed fosfomycin for RUTI at our institution was performed. Excluded were patients who did not take fosfomycin. Data collected included demographics, baseline voiding function/urological anatomic abnormalities, need for IV antibiotic therapy for RUTI, RUTI-related surgery, antibiotic allergies, and urine culture results before and after taking fosfomycin. Success was defined as no subsequent IV antibiotic use for RUTI management after fosfomycin within the study follow-up. Secondary outcomes included time to next UTI after fosfomycin, time to next extended-spectrum beta-lactamase UTI, factors predicting failure, urine culture results after fosfomycin, and need for surgical intervention. RESULTS: Between 2013 and 2019, 105 women met study criteria. At a median follow-up (including phone interviews) of 1.7 years (interquartile range, 0.3-5.8) after fosfomycin, the success rate was 74%. Twenty-seven patients had documented sterile urine cultures immediately after fosfomycin. Prior history of hospitalization for UTI and infection with resistant organisms were predictive of failure. After fosfomycin, 25 women underwent bladder electrofulguration, and 3 required cystectomy. CONCLUSIONS: Fosfomycin reduced the rate of IV antibiotic therapy in the management of RUTI in women with multidrug-resistant organisms and/or antibiotic allergies. Fosfomycin was less effective in those with prior hospitalization for UTI or infection with resistant organisms.


Assuntos
Fosfomicina , Infecções Urinárias , Antibacterianos/uso terapêutico , Feminino , Humanos , Estudos Retrospectivos , Bexiga Urinária , Infecções Urinárias/tratamento farmacológico , Infecções Urinárias/prevenção & controle
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