In vitro susceptibility to fosfomycin in clinical and environmental extended-spectrum beta-lactamase producing and/or ciprofloxacin-non-susceptible Escherichia coli isolates

ABSTRACT Extended-spectrum beta-lactamase producing and ciprofloxacin-non-susceptible Escherichia coli are clinical and environmental issues. We evaluated the susceptibility profile of fosfomycin in non-susceptible E. coli isolated from urine and the environment. We measured the activity of fosfomycin against 319 and 36 E. coli strains from urine and environmental isolates, respectively, collected from rivers. Fosfomycin resistance profiles were investigated using the minimal inhibitory concentration (MIC), according to the Clinical and Laboratory Standards Institute (CLSI) and the European Committee for Antimicrobial Susceptibility Testing (EUCAST) guidelines. Antibiotic susceptibility testing revealed that 5% and 6.6% of urine samples were non-susceptible to fosfomycin according to CLSI and EUCAST guidelines, respectively. The fosfomycin MIC50/90 was 0.5/4 mg/L. Of the 36 E. coli isolates from river water, 11.1% and 13,8% were non-susceptible to fosfomycin according to CLSI and EUCAST, respectively (range ≤0.25 ≥512 mg/L). All the isolates with MIC ≥512 mg/L for fosfomycin showed the fosA3 gene. Fosfomycin resistance was more frequent in the environment than in clinical samples.

Antibiotic versus cranberry in the treatment of uncomplicated urinary infection: a randomized controlled trial

SUMMARY OBJECTIVE: This study was designed to determine the effect of cranberry extract used in patients with single urinary tract infections. METHODS: Patients with simple-type urinary tract infections were divided into two groups. Treatment with fosfomycin or cranberry tablet was started. On days 1, 3, and 7 of the treatment, whether there was a decrease in the complaints was evaluated with a Likert-type scale. The recovery status of urinary tract infections and the well-being of patients were compared via antibiotic and cranberry groups. RESULTS: After the treatment, the leukocyte levels of the cranberry users were at the same level as those of the other group, and the rate of well-being and the portion of patients that reported to be "very well" on days 3 and 7 in the cranberry group was significantly higher compared with the fosfomycin group (p<0.05). CONCLUSION: Considering the results of this study, it was determined that the patient's complaints decreased from day 3 and their well-being increased with the use of cranberry only. Specifically, on day 7, the well-being of the cranberry group was higher than that of the fosfomycin group. For this reason, cranberry is a favorable alternative to antibiotics in uncomplicated and simple urinary tract infections.

Sensibilidad de Escherichia coli frente a fosfomicina, en infecciones urinarias provenientes de personas con discapacidad que acudieron a la Secretaría Nacional por los Derechos Humanos de las Personas con Discapacidad-SENADIS / Susceptibility of Escherichia coli against fosfomycin in urinary tract infections from people with disabilities who attended SENADIS

INTRODUCCIÓN: Fosfomicina es un antimicrobiano de amplio espectro utilizado para el tratamiento de las infecciones urinarias bajas; tiene actividad sobre bacilos gramnegativos y cocos grampositivos, así también sobre microorganismos multirresistentes, además de ofrecer una alternativa terapéutica de administración vía oral en dosis única, alcanzando una efectividad de 90%. OBJETIVO: Conocer la sensibilidad in vitro de Escherichia coli frente a fosfomicina, en infecciones urinarias provenientes de personas con discapacidad. MATERIAL Y MÉTODO: Estudio observacional, descriptivo, prospectivo, en el que se incluyó un total de 273 muestras de urocultivo, de pacientes de ambos sexos que acudieron a SENADIS, y que en el momento de la consulta presentaban síntomas de infección del tracto urinario, por lo que se les solicitó el análisis de orina simple y cultivo. De las muestras procesadas en el laboratorio de microbiología, que fueron positivas con crecimiento bacteriano significativo, se procedió a la identificación bacteriana y a la realización del antibiograma según las recomendaciones de CLSI. RESULTADOS: De estas 273 muestras, 91 fueron positivas para diferentes uropatógenos, 62/91 (68%) resultaron ser E. coli. De estas cepas de E. coli, 59/62 (95%) mostraron sensibilidad in vitro a fosfomicina. Comentario: Aunque el número de muestra obtenido es pequeño y no extrapolable ampliamente, pretendemos extender el trabajo por un tiempo más para compararlo más adelante. CONCLUSIONES: Se observa que fosfomicina presenta buena actividad in vitro frente a cepas de E. coli aisladas de urocultivo, pudiendo representar una buena alternativa terapéutica a ser utilizada en la población en estudio.

BACKGROUND: Fosfomycin is a broad-spectrum antibiotic used for the treatment of lower urinary tract infections, it is active against gramnegative bacilli and grampositive cocci, as well as against multi-resistant microorganism, in addition to offering a therapeutic alternative for oral administration in a single dose, reaching an effectiveness of 90%. AIM: To study the susceptibility of Escherichia coli to fosfomycin in urinary tract infections, of isolated strains obtained from patients with disabilities. METHODS: It is an observational, descriptive, prospective study in which a total of 273 urine culture samples of patients of both sexes who attended the SENADIS were included, and who at the time of the consultation presented symptoms of urinary tract infection. The urine positive cultures with significant bacterial growth were performed to determine its bacterial identification and the antibiogram according to CLSI recommendations. RESULTS: Of these 273 samples, 91 samples were positive for different uropathogens, with 62/91 (68%) being positive for E. coli. Of these E. coli strains, 59/62 (95%) showed in vitro susceptibility to fosfomycin. Comment: Although the number of samples obtained is small and it cannot be extrapolated, we pretend to extend the work for a while longer to be able to compare it later. CONCLUSION: Fosfomycin has good activity in vitro against E. coli isolated from urine culture in our institution, representing a good alternative to be used in our study population

Mecanismos de resistencia a la colistina, la nitrofurantoína y la fosfomicina en Enterobacterales / Mechanisms of resistance to colistin, nitrofurantoin and fosfomycin in Enterobacteriaceae

Resumen Las enterobacterias son un grupo amplio y heterogéneo de bacilos Gram negativos que se aíslan de forma rutinaria en el laboratorio clínico y se asocian a una gran cantidad de cuadros clínicos. Aquellas resistentes a antibióticos de última línea, como a los carbapenémicos, representan un gran reto en los centros de salud. Ante la dificultad para tratar infecciones causadas por este tipo de bacterias, se ha retomado el uso de antimicrobianos clásicos como la colistina, la nitrofurantoína y la fosfomicina. El objetivo de este trabajo es detallar los principales mecanismos de resistencia para estos tres fármacos descritos en enterobacterias. Para ello, se efectuó una revisión bibliográfica de artículos científicos publicados entre los años 1999 y 2022, utilizando las bases de datos PubMed (NCBI), PLOS, Redalyc, Google Scholar y Science Direct. En este proceso, se usaron las palabras clave "Carbapenem-Resistant Enterobacteriaceae", "colistin", nitrofurantoin", "fosfomycin", "resistance" y "plasmids". Se encontró que los mecanismos de resistencia son variados y abarcan fenómenos como modificación del sitio blanco, inactivación enzimática, impermeabilidad y eflujo. Además, los determinantes genéticos de resistencia se encuentran en cromosomas o en plásmidos. Conocer este tipo de información permite mejorar la vigilancia basada en el laboratorio, combatir el problema de resistencia a los antimicrobianos y optimizar el uso de estos antibióticos que forman parte del escaso arsenal para el tratamiento de ciertas infecciones causadas por microorganismos multidrogorresistentes.

Abstract Enterobacteriaceae is a large and heterogeneous group of Gram-negative bacilli that are routinely isolated in the clinical laboratory and are associated with a large number of clinical conditions. Those resistant to last-line antibiotics, such as carbapenems, represent a great challenge in health-care centers. Given the difficulty in treating this type of infections, the use of old drugs such as colistin, nitrofurantoin and fosfomycin has been studied. The objective of this work is to detail the main resistance mechanisms described in Enterobacteriaceae for these three antibiotics. To do this, a survey of scientific articles from the years 1999 to 2022 was carried out using databases such as PubMed (NCBI), Google Scholar, PLOS, Redalyc and Science Direct. In this process, keywords "Carbapenem- Resistant Enterobacteriaceae", "colistin", nitrofurantoin", "fosfomycin", "resistance" and "plasmids" were used. Resistance mechanisms were found to be varied and involve phenomena such as target site modification, enzyme inactivation, impermeability, and efflux. In addition, the genetic determinants of resistance are found at the chromosomal level or in plasmids. Knowing this type of information makes it possible to improve laboratory-based surveillance, fight the problem of resistance to antibiotics and take care of these antibiotics, which are part of the scarce arsenal for the treatment of certain infections caused by multidrug-resistant microorganisms.

Analytical Method Development And Validation For The Estimation Of Fosfomycin Trometamol In Its Bulk And Pharmaceutical Dosage Form

The goal of the current study is to develop and validate a new chromatographic method for Fosfomycin Trometamol's determination in both pure form and pharmaceutical formulation. In the present study, a pre chromatographic derivatization of Fosfomycin Trometamol was done by forming an ion-pair complex of Heterocyclic nitrogen using the acidic dye methyl orange and phthalate buffer of pH-6. The yellow ion-pair complex was extracted with chloroform and it was further extracted with aqueous solution of 0.01M HCL. The ion-pair complex of Fosfomycin Trometamol and methyl orange obeyed Beer's law in the range of 30 -70 ?g/ml with a correlation coefficient (r2) of 0.9946. A Liquid chromatography system equipped with an Agilent ACE C18 column (250 X 4.6mm, 5?m) was used as a stationary phase in this work. The developed method was validated according to ICH guidelines. For determining the medication in bulk and formulation, the devised approach was proven to be accurate, sensitive, and repeatable

Evaluation of the combination treatments with intravenous fosfomycin for carbapenem-resistant Klebsiella pneumoniae

SUMMARY OBJECTIVE: The aim of this study was to evaluate the combination treatments with intravenous fosfomycin for carbapenem-resistant Klebsiella pneumoniae infections in a tertiary-care center. METHODS: Between December 24, 2018 and November 21, 2022, adult patients diagnosed with bloodstream infection or ventilator-associated pneumonia due to culture-confirmed carbapenem-resistant Klebsiella pneumoniae in the anesthesiology and reanimation intensive care units were investigated retrospectively. RESULTS: There were a total of 62 patients fulfilling the study inclusion criteria. No significant difference was recorded in 14- and 30-day mortality among different types of combination regimens such as fosfomycin plus one or two antibiotic combinations. Hypokalemia (OR:5.651, 95%CI 1.019-31.330, p=0.048) was found to be a significant risk factor for 14-day mortality, whereas SOFA score at the time of diagnosis (OR:1.497, 95%CI 1.103-2.032, p=0.010) and CVVHF treatment (OR:6.409, 95%CI 1.395-29.433, p=0.017) were associated with 30-day mortality in multivariate analysis. CONCLUSION: In our study, high mortality rates were found in patients with bloodstream infection or ventilator-associated pneumonia due to carbapenem-resistant Klebsiella pneumoniae, and no significant difference was recorded in 14- and 30-day mortality among different types of combination regimens such as fosfomycin plus one or two antibiotic combinations.

Synergistic antimicrobial potential of EGCG and fosfomycin against biofilms associated with endodontic infections

Abstract Objective This study aimed to evaluate the cytotoxicity and synergistic effect of epigallocatechin gallate (EGCG) and fosfomycin (FOSFO) on biofilms of oral bacteria associated with endodontic infections. Methodology This study determined minimum inhibitory and bactericidal concentration (MIC/MBC) and fractionated inhibitory concentration (FIC) of EGCG and FOSFO against Enterococcus faecalis, Actinomyces israelii, Streptococcus mutans, and Fusobacterium nucleatum. Monospecies and multispecies biofilms with those bacteria formed in polystyrene microplates and in radicular dentin blocks of bovine teeth were treated with the compounds and control chlorhexidine (CHX) and evaluated by bacterial counts and microscopy analysis. Toxicity effect of the compounds was determined on fibroblasts culture by methyl tetrazolium assays. Results The combination of EGCG + FOSFO demonstrated synergism against all bacterial species, with an FIC index ranging from 0.35 to 0.5. At the MIC/FIC concentrations, EGCG, FOSFO, and EGCG+FOSFO were not toxic to fibroblasts. EGCG+FOSFO significantly reduced monospecies biofilms of E. faecalis and A. israelli, whereas S. mutans and F. nucleatum biofilms were eliminated by all compounds. Scanning electron microscopy of multispecies biofilms treated with EGCG, EGCG+FOSFO, and CHX at 100x MIC showed evident biofilm disorganization and substantial reduction of extracellular matrix. Confocal microscopy observed a significant reduction of multispecies biofilms formed in dentin tubules with 84.85%, 78.49%, and 50.6% of dead cells for EGCG+FOSFO, EGCG, and CHX at 100x MIC, respectively. Conclusion EGCG and fosfomycin showed a synergistic effect against biofilms of oral pathogens related to root canal infections without causing cytotoxicity.

UhpTE350Q mutation along with the presence of fosA6/5 genes in the genome probably contributes to inherent fosfomycin resistance of Klebsiella pneumoniae / 南方医科大学学报

OBJECTIVE@#To investigate the molecular mechanism underlying inherent fosfomycin resistance of Klebsiella pneumoniae (K. pneumoniae).@*METHODS@#The draft genomic sequences of 14 clinical hypervirulent/hypermucoviscous K. pneumoniae (HvKP/ HmKP) isolates were obtained using the next-generation sequencing technology. The genomic sequences were analyzed using the Resistance Gene Identifier (RGI) software for predicting the resistome based on homology and SNP models in the Comprehensive Antibiotic Resistance Database (CARD) and for identification of the presence of phosphomycin resistancerelated genes uhpt and fosA and their mutations in the bacterial genomes. The results were verified by analyzing a total of 521 full-length genomic sequences of K. pneumonia strains obtained from GenBank.@*RESULTS@#All the 14 clinical isolates of HvKP/ HmKP carried hexose phosphate transporter (UhpT) gene mutation, in which the glutamic acid was mutated to glutamine at 350aa (UhpTE350Q mutation); the presence of fosA6 gene was detected in 12 (85.71%) of the isolates and fosA5 gene was detected in the other 2 (14.29%) isolates. Analysis of the genomic sequences of 521 K. pneumonia strains from GenBank showed that 508 (97.50%) strains carried UhpTE350Q mutation, 439 (84.26%) strains harbored fosA6, and 80 (15.36%) strains harbored fosA5; 507 (97.31%) strains were found to have both UhpTE350Q mutation and fosA6/5 genes in the genome. Only 12 (2.30%) strains carried fosA6/5 genes without UhpTE350Q mutation; 1 (0.19%) strain had only UhpTE350Q mutation without fosA6/5 genes, and another strain contained neither UhpTE350Q mutation nor fosA6/5 genes.@*CONCLUSION@#UhpTE350Q mutation with the presence of fosA6/5 genes are ubiquitous in K. pneumonia genomes, indicating a possible intrinsic mechanism of fosfomycin resistance in the bacterium to limit the use of fosfomycin against infections caused by K. pneumoniae, especially the multi-resistant HvKP/HmKP strains.

Antibiotic susceptibility and fosfomycin resistance characterization in a cohort of children older than 6 years of age with urinary tract infection / Sensibilidad antibiótica y caracterización de la resistencia a fosfomicina en una cohorte de niños mayores de 6 años con infección urinaria

Fosfomycin tromethamol (FT) was reintroduced as an option for the treatment of low urinary tract infection (UTI) in children. In this study, we described the antibiotic sensitivity and mechanisms of resistance to fosfomycin in isolates from children older than 6 years with UTI. Urine culture and antibiotic susceptibility study were performed. In fosfomycin resistant strains, PCR for fos, blaCTX-M was performed followed by classification by phylogenetic group and sequencetyping. Escherichia coli was the most frequent etiological agent (89.2%). The susceptibility percentages were: fosfomycin 97.9%; amoxicillin-clavulanate 92.7%; cefuroxime and ceftriaxone 99%; nitrofurantoin 94.4%. An E. coli strain (ST69, phylogenetic group D) was resistant to fosfomycin (MIC 256mg/l) and carried the blaCTX-M-14 and fosA3 genes in a 45kb IncN-type plasmid.

La fosfomicina-trometamol (FT) se reintrodujo como una opción para el tratamiento de la infección del tracto urinario (ITU) baja en niños. En este estudio describimos la sensibilidad antibiótica y los mecanismos de resistencia a FT en aislamientos de niños mayores de 6 anos con ITU. Se realizaron urocultivos y estudios de sensibilidad antibiótica. En las cepas resistentes a fosfomicina se realizó la técnica de PCR para fos, blaCTX-M, y su identificación según su grupo filogenéticoy secuenciotipo. Escherichiacoli fue el agente etiológico más frecuente (89,2%). Los porcentajes de sensibilidad fueron: fosfomicina 97,9%; amoxicilina-clavulánico 92,7%; cefurox-ima y ceftriaxona 99%; nitrofurantoína 94,9%. Una cepa de E. coli (ST69, grupo filogenético D) fue resistente a fosfomicina (CIM 256mg/l) y portaba los genes blaCTX-M-14 y fosA3 en un plás-mido de 45 kb del tipo IncN. Este es el primer reporte de E. coli ST69 con blaCTX-M-14/fosA3 de origen humano.

Sensibilidad in vitro de Escherichia coli a la fosfomicina en urocultivos en un Servicio Asistencial Privado de Asunción / In vitro sensitivity of Escherichia coli to fosfomycin in urine cultures in a private healthcare service in Asunción

La fosfomicina es un antibiótico natural, que actúa sobre la síntesis de la pared celular, con actividad bactericida y de amplio espectro. En este trabajo se evaluó la sensibilidad in vitro de aislados de Escherichia coli (E. coli), incluidos aquellos que producen Beta Lactamasa de Espectro Extendido (BLEE) obtenidos a partir de urocultivos, tomados en diferentes lapsos de colección de datos, en personas de ambos sexos. Fueron incluidos 260 muestras de orina con desarrollo de E. coli provenientes de pacientes que concurrieron al Laboratorio San Roque. El aislamiento e identificación bacteriana se realizó según métodos convencionales y la sensibilidad a los antimicrobianos por el método de difusión de disco. Para la detección de la sensibilidad frente a fosfomicina fueron utilizados discos de 200 µg con el agregado de 50 µg de glucosa 6-fosfato. Se observó frente a los antibióticos evaluados mayor sensibilidad a fosfomicina (98,5%) y nitrofurantoína (97,7%). Ciprofloxacina, trimetoprima y la combinación sulfametoxazol/trimetoprima exhibieron frente a los mismos aislados sensibilidad menor y muy similar entre ellos, con 64,2%, 61,2% y 61,2% respectivamente. En 44 (16,9%) de los aislados de E. coli se detectó la presencia de BLEE y es destacable la alta sensibilidad que mostraron fosfomicina y nitrofurantoína, aún frente a los aislados BLEE positivos, con frecuencias de 90,9% y 93,2%, respectivamente. En resumen, la alta sensibilidad demostrada en el presente estudio por E. coli ante la fosfomicina, abre la posibilidad de considerar a este antibiótico de primera elección en las infecciones urinarias bajas, aún en los casos de gérmenes productores de BLEE, en la población de nuestro país.

Fosfomycin is a natural antibiotic, which acts on the synthesis of the cell wall, with broad spectrum bactericidal activity. In this study, the in vitro sensitivity of Escherichia coli (E. coli) isolates was evaluated, including those that produce Extended Spectrum Beta Lactamase (ESBL) obtained from urine cultures taken at different data collection times, in people of both sexes. Were included 260 urine samples with development of E. coli from patients who attended the San Roque laboratory. Bacterian isolation and identification was carried out according to conventional methods and antimicrobial sensitivity by the disk diffusion method. For detection of sensitivity to fosfomycin, 200 µg discs were used with the addition of 50 µg of glucose 6-phosphate. A greater sensitivity for fosfomycin (98.5%) and nitrofurantoin (97.7%) was observed against the evaluated antibiotics. Ciprofloxacin, trimethoprim and the sulfamethoxazole / trimethoprim combination exhibited in front of the same isolated lower sensitivity and very similar among them, with 64.2%, 61.2% and 61.2% respectively. In 44 (16.9%) of the E. coli isolates the presence of ESBL was detected and the high sensitivity shown by fosfomycin and nitrofurantoin is noteworthy, even compared to the positive ESBL isolates, with frequencies of 90.9% and 93,2%, respectively. In summary, the high sensitivity demonstrated in the present study by E. coli to fosfomycin opens the possibility of considering this first-choice antibiotic in lower urinary infections, even in ESBL-producing germs, in the population of our country.

Fosfomicina en el tratamiento de la infección urinaria baja en niños mayores de 6 años. Evolución clínico-microbiológica / Fosfomycin for low urinary-tract infections in children of over 6 years of age. Clínical-microbiological evolution / Fosfomicina no tratamento da infecção do trato urinário baixo em crianças maiores de 6 anos de idade. Evolução clínico-microbiológica

Resumen: Introducción: fosfomicina trometamol (FT) representa una alternativa al tratamiento de la infección del tracto urinario (ITU) baja. Uruguay no dispone de información acerca de su uso en niños. Objetivo: describir la evolución clínica y microbiológica de una cohorte de niños mayores de 6 años con ITU baja tratados con FT. Material y método: se incluyeron niños mayores de 6 años con ITU baja de dos prestadores de salud de Montevideo, entre 1/2/2018 - 30/6/2019. A todos se indicó FT 2 g monodosis y urocultivo de control. Se realizó seguimiento telefónico. Se evaluó: clínica, antecedentes de ITU, microorganismo, susceptibilidad antimicrobiana y evolución: tiempo de resolución clínica, resolución microbiológica, efectos adversos, recurrencia en los primeros tres meses. Resultados: se incluyeron 46 niños, mediana de edad 9,4 años, antecedentes de ITU 13. Presentaron disuria 44, tenesmo 33, polaquiuria 31. Microorganismo aislado: E. coli 43, S. saprophyticus 2, Proteus sp 1. Todos susceptibles a FT, excepto S. saprophyticus naturalmente resistente. Resolución clínica en 48 horas: 42. Se obtuvo urocultivo de control en 31/46 niños: resolución microbiológica 22, no resolución 5 y contaminado 4. Presentaron efectos adversos 9: vómitos 1, diarrea 8 y cefalea 1. Seguimiento telefónico a 40/46 pacientes: reinfecciones al mes de tratamiento: 6. Conclusiones: no se registró resistencia adquirida en los microorganismos. Se observó resolución clínica en las primeras 48 horas en la mayoría de los casos. Los efectos adversos fueron leves. Ocurrieron reinfecciones en una proporción pequeña. Los resultados avalan a FT como alternativa terapéutica para ITU baja en mayores de 6 años.

Summary: Introduction: fosfomycin tromethamine (FT) is an alternative to the treatment of low urinary tract infection (UTI). Uruguay does not have information about its use in children. Objective: to describe the clinical and microbiological evolution of a cohort of children older than 6 years of age with low UTI treated with FT. Materials and methods: we included children of over 6 years of age with low UTI from two health providers in Montevideo between 2/1/2018 and 6/30/2019. We prescribed a single dose of FT 2 g and a control urine culture to all patients. We carried out a telephone follow-up and assessed their clinical record, history of UTI, microorganisms, antimicrobial susceptibility and evolution: time of clinical resolution, microbiological resolution, adverse effects, and recurrence during the first 3 months. Results: 46 children were included, median age 9.4 years, history of UTI 13. 44 presented dysuria, 33 tenesmus, 31 pollakiuria. Isolated microorganism: E. coli 43, S. saprophyticus 2, Proteus sp 1. All susceptible to FT, except S. saprophyticus, naturally resistant. Clinical resolution in 48 hours: 42. Control urine culture was obtained in 31/46 children: microbiological resolution 22, no resolution 5 and contaminated 4. Adverse effects 9: vomiting 1, diarrhea 8, and headache 1. Telephone follow-up carried out for 40 / 46 patients: reinfections after one month of treatment: 6. Conclusions: microorganisms had not acquired resistance. Most cases showed clinical resolution during the first 48 hours. Adverse effects were mild. Reinfections occurred in a small proportion. The results support FT as a therapeutic alternative for low UTI for the case of children of over 6 years of age.

Resumo: Introdução: A fosfomicina trometamina (FT) é uma alternativa ao tratamento da infecção do trato urinário baixo (ITU). O Uruguai não possui informações sobre seu uso em crianças. Objetivo: Descrever a evolução clínica e microbiológica de uma coorte de crianças maiores de 6 anos de idade com ITU baixa tratada com TF. Materiais e métodos: Foram incluídas crianças maiores de 6 anos de com ITU baixa de dois provedores de saúde em Montevidéu; no período 1/2 / 2018 e 30/06/2019. Todos os pacientes receberam indicação de FT 2 g em dose única, cultura de urina e controle. Realizou-se um rastreamento por telefone. Se avaliou: prontuário clínico, história de ITU, microrganismos, suscetibilidade a antimicrobianos e evolução: tempo de resolução clínica, resolução microbiológica, efeitos adversos, recorrência nos primeiros 3 meses. Resultados: Incluíram-se 46 crianças, mediana de idade 9,4 anos, história de ITU 13. 44 delas apresentaram disúria, tenesmo 33, polaciúria 31. Microrgoanismo isolado: E. coli 43, S. saprophyticus 2, Proteus sp 1. Todas suscetíveis a FT, exceto S. saprophyticus, naturalmente resistente. Resolução clínica em 48 horas: 42. Obtivemos cultura de urina controle em 31/46 crianças: resolução microbiológica 22, sem resolução 5 e contaminada 4. 9 delas apresentaram efeitos adversos 9: vômito 1, diarreia 8 e dor de cabeça 1. Realizamos acompanhamento telefônico em 40 / 46 pacientes: reinfecções um mês após tratamento, 6. Conclusões: Os microrganismos não adquiriram resistência. Na maioria dos casos observou-se resolução clínica nas primeiras 48 horas. Os efeitos adversos foram leves. As reinfecções ocorreram em pequena proporção. Os resultados apoiam o TF como uma alternativa terapêutica para ITU baixa para casos de crianças maiores de 6 anos de idade.

First characterization of K. pneumoniae ST11 clinical isolates harboring blaKPC-3 in Latin America / Primera caracterización de aislamientos clínicos de K. pneumoniae ST11 portadoresde blaKPC-3en América Latina

Abstract Antimicrobial resistance due to carbapenemase production in Enterobacteriaceaeclinical isolates is a global threat. Klebsiella pneumoniae harboring the blaKPCgene is one ofthe major concerns in hospital settings in Latin America.The aim of this study was to characterize the antibiotic resistance mechanisms and to typifyfour carbapenem-resistant K. pneumoniae clinical isolates from the city of Manizales, Colombia.We identified blaKPC-3in all four isolates by polymerase chain reaction and subsequentsequencing. The plasmid-mediated quinolone resistance genes qnrB19-like and aac(6)Ib-cr;fosfomycin resistance gene fosA and an insertion sequence IS5-like in mgrB (colistin resistance)were also detected. Sequence types ST11 with capsular type wzi75, and ST258 with wzi154,were characterized. The blaKPC-3gene was mobilized in a 100-kb IncFIB conjugative plasmidwith vagCD toxin-antitoxin system.This work reports multiple resistance genes in blaKPC-producing K. pneumoniae and the firstoccurrence of ST11 clinical isolates harboring blaKPC-3in Latin America.

Resumen La resistencia a antibióticos mediada por la producción de carbapenemasas en aislamientos clínicos de Enterobacteriaceae es una amenaza mundial. Klebsiella pneumoniae portador de blaKPC es uno de los mayores problemas a nivel hospitalario en Latinoamérica. El objetivo de este estudio fue caracterizar los mecanismos de resistencia antibiótica y tipificar cuatro aislamientos clínicos de K. pneumoniae resistentes a carbapenems obtenidos en la ciudad de Manizales, Colombia. Se identificó blaKPC-3 en todos los aislamientos mediante reacción en cadena de polimerasa y secuenciación. También se detectaron los genes de resistencia transferible a quinolonas qnrB19-like y aac(6')Ib-cr y a fosfomicina fosA, y la secuencia de inserción /S5-like en mgrB (asociada a la resistencia a colistina). Se caracterizaron los secuenciotipos ST11 (cápsula wzi75) y ST258 (cápsula wzi154). Se comprobó que blaKPC-3 fue movilizado por un plásmido conjugativo IncFIB-vagCD de 100kb. En este trabajo se reportan múltiples genes de resistencia en K. pneumoniae productor de blaKPC y se describen por primera vez aislamientos clínicos ST11 productores de blaKPC-3 en Latinoamérica.

Determination of nitrofurantoin and fosfomycin susceptibility among urinary Escherichia coli isolates

Background: Urinary tract infections (UTIs) are one of the most common infections. For treatment of UTIs, there are limited antibiotics due to increased resistance among uropathogens. Two older antibiotics; Nitrofurantoin and Fosfomycin have become novel oral therapeutic options against uropathogens. Aim of the study was to identify UTI causing micro-organisms and evaluate in-vitro activity of nitrofurantoin and fosfomycin against most common isolated organism (E. coli).Methods: Results of urine samples culture and susceptibility testing over a period of 1 year were analysed and included in this study.Results: Micro-organisms were isolated from 568 urine samples. Most commonly isolated organism was Escherichia coli (40.50%), followed by Klebsiella spp. (20.07%) and Staphylococcus spp. (17.07%). Susceptibility of E. coli to nitrofurantoin and fosfomycin was 91.74% and 65.65% respectively. Conclusion: Good activity of nitrofurantoin and fosfomycin against E. coli indicates that these two drugs are potential therapeutic alternatives for urinary tract infections.

Susceptibility of Urinary Escherichia coli to Fosfomycin and Nitrofurantoin- Re-Exploration of Old and Forgotten Oral Antibiotics

Urinary tract infections (UTI) are one of the most common causes for patients to seek medical attention and also for prescription of antibiotics. Escherichia coli is the most common pathogen isolated from both complicated and uncomplicated UTI. Frequent and inappropriate use of antibiotics has led to antimicrobial resistance in the organisms. Multidrug resistance and carbapenem resistance are posing greater challenges to the clinicians. With only few antibiotics expected to be in the pipeline in the continuing five to ten years, the options that we are left with today are prudent use of antibiotics and re-exploration of old and forgotten antibiotics like nitrofurantoin, fosfomycin to help in combating the development of further resistance.METHODSThis study was conducted in the Department of Microbiology, of our tertiary care hospital from March 2019 to June 2019. Retrospective analysis of results of urine culture was done. Isolates resistant to one antibiotic in at least three classes were considered as multidrug resistant. Susceptibility to fosfomycin and Nitrofurantoin among the MDR and non-MDR isolates were comparedRESULTSEscherichia coli (66.67 %) was the most common Enterobacteriaceae to be isolated, followed by Klebsiella pneumoniae (25.49 %). A very high susceptibility was noted to fosfomycin and Nitrofurantoin, with only 2.91 % and 14.04 % of the isolates being resistant to fosfomycin and nitrofurantoin respectively. Highest resistance was noted against ampicillin with 485 (83.05 %) being resistant followed by ciprofloxacin (65.75 %), norfloxacin (62.84 %), cotrimoxazole (47.09 %) and amoxicillin-clavulanic acid (36.99 %). About 49.14 % of the isolates were found to be multi-drug resistant. There was no significant difference in the resistance rates to fosfomycin among the MDR (3.83 %) and non-MDR isolates (2.02 %), while 20.55 % of the MDR isolates and 7.74 % of non-MDR isolates were resistant to nitrofurantoin.CONCLUSIONSDue to emergence of resistance to commonly used oral antibiotics in UTI, among the two older drugs- Nitrofurantoin and Fosfomycin, the latter can be used for treatment of acute cystitis, especially in cases due to MDR Escherichia coli, as Fosfomycin is equally effective against both MDR and non-MDR Escherichia coli isolated from urine samples while nitrofurantoin may be less effective against the MDR strains.

In vitro Assessment of Fosfomycin: A Beacon of Hope in Drug Resistant Organisms Causing Urinary Tract Infections

Introduction:Urinary tract infections (UTI) are the most common bacterial infections affecting humans.. Fosfomycin has been approved for use in uncomplicated UTI caused by E. coli and Enterococcus. However, data regarding sensitivity of organisms causing hospital acquired or complicated UTI is scarce worldwide. We aimed to determine the in vitro sensitivity of drug resistant organisms causing hospital acquired and complicated UTI towards fosfomycin. Materials and Methods:Over a 6 month period, urine samples were processed as per standard microbiological protocols. Bacterial isolates were identified by routine microbiological methods followed by automated methods. Antibiotic sensitivity tests were done for different antibiotics. Fosfomycin sensitivity was tested by disc diffusion assay and minimum inhibitory concentration (MIC) was determined by E test method. Results:A total of 248`organisms causing hospital acquired and/or complicated UTI were isolated of which E. coli 88(35.48%) was most common followed by K. pneumoniae78(31.45%) and P. aeruginosa 64(25.80%). Of 248, 92.74% (230/248) isolates were sensitive to fosfomycin. All the E. coli isolates were sensitive to fosfomycin with a low MIC (range 0.064­16 mg/L) while 97.43% (76/78) of the K. pneumoniae and 71.87% (46/64) P. aeruginosa of isolates were sensitive with a higher MIC (range 0.5­32 mg/L and 6­64mg/L respectively). Fosfomycin MIC geometric mean among E. coli, K. pneumoniaeand P. aeruginosa was; 1.05, 7.19 and 19.61 mg/L respectively. K. pneumoniae and P. aeruginosa showed a significantly higher geometric mean MIC compare to E. coli (P <0.0001).Conclusions:This study suggests that fosfomycin has the potential to replace the parenteral antibiotics for treating complicated or hospital acquired lower UTI especially in case of Enterobacteriaceae

Relative potency of different generic brands of meropenem, colistin and fosfomycin: Implications for antimicrobial therapy and antimicrobial formulary

There is a need of a relatively simple and inexpensive method for the determination of relative potency of various generic brands of antibiotics in comparison to original products. The current study describes an agar diffusion method which can be performed in any microbiology laboratory, is cheap (costs $2 per test) and its results can be available after overnight incubation. The results show that neither all generics are reliable nor are all generic antibiotics of poor quality.

Susceptibility profile, resistance mechanisms & efficacy ratios of fosfomycin, nitrofurantoin & colistin for carbapenem-resistant Enterobacteriaceae causing urinary tract infections

Background & objectives: The escalation in carbapenem resistance among Enterobacteriaceae has resulted in a lack of effective therapeutic alternatives. Older antimicrobials, fosfomycin, nitrofurantoin and colistin for urinary tract infections (UTIs) caused by carbapenem-resistant Enterobacteriaceae (CRE) may be effective treatment options. The objectives of this study were to evaluate the utility of fosfomycin, nitrofurantoin and colistin in treating UTI caused by CRE and molecular characterization of the plasmid-mediated carbapenem resistance mechanisms. Methods: Consecutive, non-duplicate isolates of CR Escherichia coli and Klebsiella spp. from urine cultures were included (n=150). Minimum inhibitory concentrations (MIC) were determined by E-test (fosfomycin and nitrofurantoin) and broth microdilution (colistin). Efficacy ratios were derived by dividing susceptibility breakpoints by observed MIC values of the drugs for the isolates. Isolates were screened for genes coding for carbapenemases using multiplex PCR. Fosfomycin, nitrofurantoin and colistin-resistant isolates were screened for plasmid-borne resistance genes fos A3, oqx AB and mcr-1, respectively using PCR. Results: Among E. coli, 98.9, 56 and 95 per cent isolates were susceptible to fosfomycin, nitrofurantoin and colistin, respectively, while 94 and 85 per cent of Klebsiella spp. were susceptible to fosfomycin and colistin, respectively. The efficacy ratios indicated fosfomycin as the drug of choice for UTI caused by CR E. coli and Klebsiella spp., followed by colistin. The blaNDM gene was most common, followed by blaOXA48-like. Plasmid-borne genes encoding resistance to fosfomycin, nitrofurantoin and colistin were absent. Interpretation & conclusions: With increasing resistance against the current treatment options, older drugs may emerge as effective options. Molecular screening of resistant isolates is essential to prevent the spread of plasmid-borne resistance against these drugs.

Molecular epidemiology and mechanisms of fosfomycin-resistant Escherichia coli producing extended-spectrum β-lactamases isolated from urine / 临床检验杂志

Objective@#To investigate the molecular epidemiology and mechanisms of fosfomycin-resistant Escherichia coli isolates producing extended-spectrum β-lactamases (ESBLs) isolated from urine. @*Methods@#Fosfomycin-resistant phenotypes were screened by drug susceptibility test in ESBLs-producing E.coli stains. The ESBLs gene and fosfomycin resistant gene were amplified by PCR. The molecular typing was analyzed by multiple sequence type (MLST). The transferability of the drug resistant gene was verified by conjugation assays. @*Results@#Among the 308 strains of E.coli isolated from urine, there were 168 (54.54%) ESBLs producing strains and 18 (10.71%, 18/168) fosfomycin resistant strains. In the drug resistant genes, the incidence of bla SHV was about 88.9% (16/18), bla CTX-M was 77.8% (14/18), bla TEM-208 was 5.6% (1/18), bla TEM-1b was 61.1% (11/18) and fosA3 was 83.3% (15/18). The main MLST genotype was ST131. The conjugation test confirmed the transferability of resistance in fosA3 positive strain. @*Conclusion@#The fosfomycin resistant rate of ESBLs producing E.coli in urethral infection was in a low level. The fosA3 gene was the main mechanism of fosomycin resistance and located on the conjugation plasmids, which should be the main node of horizontal gene transmission. We need to pay great attention to this resistant gene.

In vitro combination antimicrobial susceptibility of fosfomycin sodium / 中国感染控制杂志

Objective To evaluate in vitro antimicrobial effect of fosfomycin sodium single use and combination with other antimicrobial agents on clinically isolated Staphylococcus aureus (S.aureus), Klebsiella pneumoniae (K.pneumoniae) and Pseudomonas aeruginosa (P.aeruginosa) in China.Methods Combined antimicrobial susceptibility testing was performed with checkerboard method, minimal inhibitory concentrations (MICs) were detected by two-fold agar dilution method, susceptibility of S.aureus (n=113 strains), K.pneumoniae (n=108 strains), and P.aeruginosa (n=110 strains) isolated from 18 hospitals in China in recent three years was determined by single and combined antimicrobial susceptibility testing.Results MIC50 value of fosfomycin sodium single use were all≤32 mg/L against all tested strains, regardless of whether strains were resistant to other antimicrobial agents or not.The synergistic rate of fosfomycin sodium with levofloxacin, minocycline, oxacillin, and clindamycin against methicillin-resistant S.aureus (MRSA) was＞43％.Synergistic rate of fosfomycin sodium with levofloxacin and imipenem against imipenem-nonsusceptible P.aeruginosa was＞35％, synergistic rates of fosfomycin sodium with tested antimicrobial agents against imipenem-susceptible P.aeruginosa were all＞35％.Conclusion Fosfomycin sodium still has good antimicrobial activity against common clinical drug-resistant bacteria, such as MRSA, extended-spectrumβ-lactamase-producing K.pneumoniae and so on, it has synergistic effect with many other kinds of antimicrobial agents, suggesting that in the limited treatment of infection caused by drug-resistant bacteria, fosfomycin in combination with other antimicrobial agents may be a useful choice.

Sensibilidad a fosfomicina en Escherichia coli productoras de betalactamasas de espectro extendido / Sensitivity to Fosfomycin in Extended-spectrum Betalactamase-producing Escherichia coli

RESUMEN Las infecciones urinarias son causadas mayormente por Escherichia coli (E. coli), el uso indiscriminado de antibióticos ha originado un aumento de infecciones por cepas productoras de betalactamasas de espectro extendido (BLEE). Con el objetivo de determinar la sensibilidad a fosfomicina se realizó un estudio en cepas de E. coli productoras de BLEE aisladas de urocultivos provenientes de un hospital de Perú. Se recolectaron 266 cepas de E. coli identificadas por métodos convencionales como productoras de BLEE. Se determinó la sensibilidad de fosfomicina por concentración inhibitoria mínima mediante el método de dilución en agar y por el método de disco difusión. Se encontró 192 (72,2 %) cepas de E. coli productora de BLEE sensibles a fosfomicina. Se concluye que la fosfomicina presenta actividad antimicrobiana frente a cepas de E. coli productoras de BLEE, y podría ser considerada una buena opción terapéutica frente a cepas resistentes.

ABSTRACT Urinary infections are caused mainly by Escherichia coli (E. coli); indiscriminate use of antibiotics has caused an increase in infections due to extended-spectrum beta-lactamase (ESBL)-producing strains. Aiming to determine the sensitivity to fosfomycin, a study was conducted in ESBL-producing E. coli strains isolated from urine cultures at a hospital in Peru. Two hundred and sixty-six (266) strains of E. coli were collected, which were determined by conventional methods to be ESBL- producing. Sensitivity to fosfomycin was determined through minimum inhibitory concentration with the agar dilution method and the diffusion disc method. One hundred and ninety-two (192) (72.2%) strains of ESBL-producing E. coli strains sensitive to Fosfomycin were found. It, therefore, follows that fosfomycin exhibits antimicrobial activity against ESBL-producing E. coli strains and that it could be considered a good treatment option for resistant strains.