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1.
Curr Microbiol ; 81(3): 76, 2024 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-38267719

RESUMEN

Two metallo-ß-lactamase-producing Klebsiella pneumoniae (HA30 and HA31) were isolated in a hospital in Argentina during 2018. K. pneumoniae HA30 was isolated from a rectal swab during the epidemiological surveillance for carbapenemase-producing strains, while K. pneumoniae HA31 was collected from the same patient 4 days after hospitalization. The aim of the present study was to identify the clonal relationships and resistome of these two NDM-producing K. pneumoniae strains isolated from a patient with a fatal outcome. Whole-genome sequencing (WGS) was performed using Illumina MiSeq-I, and subsequent analysis involved genome assembly, annotation, antibiotic resistance gene identification, multilocus sequence typing (MLST), and plasmid characterization using bioinformatics tools. Conjugation assays to E. coli J53 was conducted as previously described. K. pneumoniae HA30 exhibited extensively drug-resistant phenotype, while HA31 was multidrug-resistant as defined by Magiorakos et al., including both resistance to carbapenems, aminoglycosides and ciprofloxacin with blaNDM-5, blaCTX-M-15 and rmtB genes found in both strains. MLST analysis showed that both strains belonged to ST11, differing by only 4 cgSNPs, indicating that K. pneumoniae HA30 and HA31 were the same strain. Conjugation assays revealed that K. pneumoniae HA31 strain possessed a transferable plasmid to E. coli J53. Bioinformatics studies identified that the same strain colonizing an inpatient during hospital admission subsequently caused the infection leading to a fatal outcome, being the first report of blaNDM-5, rmtB and blaCTX-M-15 genes in a K. pneumoniae ST11 strain from Latin America. Our results also highlighted the importance of focusing on epidemiological surveillance programs.


Asunto(s)
Escherichia coli , Klebsiella pneumoniae , Humanos , Klebsiella pneumoniae/genética , Tipificación de Secuencias Multilocus , Genómica , Antibacterianos/farmacología , beta-Lactamasas/genética
2.
Rev Argent Microbiol ; 56(1): 33-61, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38368217

RESUMEN

The aim of this study was to compare the performance of two MALDI-TOF MS systems in the identification of clinically relevant strict anaerobic bacteria. The 16S rRNA gene sequencing was the gold standard method when discrepancies or inconsistencies were observed between platforms. A total of 333 isolates were recovered from clinical samples of different centers in Buenos Aires City between 2016 and 2021. The isolates were identified in duplicate using two MALDI-TOF MS systems, BD Bruker Biotyper (Bruker Daltonics, Bremen, Germany) and Vitek MS (bioMèrieux, Marcy-l'Etoile, France). Using the Vitek MS system, the identification of anaerobic isolates yielded the following percentages: 65.5% (n: 218) at the species or species-complex level, 71.2% (n: 237) at the genus level, 29.4% (n: 98) with no identification and 5.1% (n: 17) with misidentification. Using the Bruker Biotyper system, the identification rates were as follows: 85.3% (n: 284) at the species or species-complex level, 89.7% (n: 299) at the genus level, 14.1% (n: 47) with no identification and 0.6% (n: 2) with misidentification. Differences in the performance of both methods were statistically significant (p-values <0.0001). In conclusion, MALDI-TOF MS systems speed up microbial identification and are particularly effective for slow-growing microorganisms, such as anaerobic bacteria, which are difficult to identify by traditional methods. In this study, the Bruker system showed greater accuracy than the Vitek system. In order to be truly effective, it is essential to update the databases of both systems by increasing the number of each main spectrum profile within the platforms.


Asunto(s)
Bacterias Anaerobias , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Bacterias Anaerobias/genética , ARN Ribosómico 16S/genética , Argentina
3.
Anaerobe ; 82: 102744, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37302567

RESUMEN

Toxin-producing Clostridioides difficile infection (CDI) is the leading cause of hospital-acquired diarrhea. However, it is now recognized as a cause of diarrhea in the community. This single-center study aimed to determine the epidemiological origin of CDI cases between January 2014 and December 2019 and to compare demographic characteristics, comorbidities, risk factors, severity, and mortality of community CDI with healthcare facility-associated CDI. There were 52 CDI cases from the community (34.4%). Community patients were significantly younger (53 yo vs. 65 yo), less comorbid (Charlson Index 1.65 vs. 3.98), and less severe (only one case). The main risk factor was the use of antibiotics in the previous 90 days (65%). However, we did not find any known risk factor in 7 patients.


Asunto(s)
Clostridioides difficile , Infecciones por Clostridium , Infecciones Comunitarias Adquiridas , Infección Hospitalaria , Humanos , Infecciones Comunitarias Adquiridas/epidemiología , Hospitales Generales , Argentina/epidemiología , Infecciones por Clostridium/epidemiología , Diarrea/epidemiología , Infección Hospitalaria/epidemiología
4.
Rev Argent Microbiol ; 55(4): 337-344, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37127474

RESUMEN

This study aimed to assess the impact of the implementation of a rapid multiplex molecular FilmArray Respiratory Panel (FRP) on the medical management of immunocompromised patients from a community general hospital. We conducted a single-center, retrospective, and before-after study. Two periods were evaluated: before the implementation of the FRP (pre-FRP) from April 2017 to May 2018 and after the implementation of the FRP (post-FRP) from January to July 2019. The inclusion criteria were immunocompromised patients over 18 years of age with suspected acute respiratory illness tested by conventional diagnostic methods (pre-FRP) or the FilmArray™ Respiratory Panel v1.7 (post-FRP). A total of 142 patients were included, 64 patients in the pre-FRP and 78 patients in the post-FRP. The positive detection rate was significantly higher in the post-FRP (63% vs. 10%, p<0.01). There were more patients receiving antimicrobial treatment in the pre-FRP compared with the post-FRP period (94% vs. 68%, p<0.01). A decrease in beta-lactam (89% vs. 61%, p<0.01) and macrolide (44% vs. 13%, p<0.01) prescriptions were observed in the post-FRP. No differences were observed in oseltamivir use (22% vs. 13%, p=0.14), changes in antimicrobial treatment, hospital admission rate, days-reduction in droplet isolation precautions, hospital length of stay (LOS), admission to intensive care unit (ICU), LOS in ICU, treatment failure and 30-day mortality. The implementation of the FRP impacted patient care by improving diagnostic yield and optimizing antimicrobial treatment in immunocompromised adult patients.


Asunto(s)
Antiinfecciosos , Infecciones del Sistema Respiratorio , Adulto , Humanos , Adolescente , Antibacterianos/uso terapéutico , Estudios Retrospectivos , Estudios Controlados Antes y Después , Reacción en Cadena de la Polimerasa Multiplex/métodos , Infecciones del Sistema Respiratorio/diagnóstico , Infecciones del Sistema Respiratorio/tratamiento farmacológico , Prescripciones , Huésped Inmunocomprometido
5.
Anaerobe ; 73: 102500, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34890813

RESUMEN

Two commercial MALDI-TOF MS systems were used to identify 18 isolates, belonging to the Peptoniphilus genus; also the 16S rRNA sequencing identity was compared against the MALDI-TOF MS system results. Bruker Biotyper system provided higher accuracy than Vitek MS system, however, adding spectra could allow a more reliable species level identification.


Asunto(s)
Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Técnicas de Tipificación Bacteriana/métodos , ARN Ribosómico 16S/genética , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos
6.
Rev Argent Microbiol ; 54(1): 31-34, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-33838970

RESUMEN

Human parechovirus (HPeV) is one of the members of the family Picornaviridae that has been associated with fever of unknown origin, gastroenteritis, clinical sepsis, meningitis, or encephalitis in very young infants. HPeV detection is not routinely performed in most clinical microbiology laboratories in Argentina and, therefore, its real prevalence is unknown. We here report three cases of HPeV CNS infection that presented to our hospital with different clinical features after the implementation of a multiplex PCR meningitis/encephalitis panel. Molecular diagnostic techniques could help improve patient care and understand the real prevalence of this infection in Argentina.


Asunto(s)
Parechovirus , Infecciones por Picornaviridae , Sepsis , Argentina , Niño , Humanos , Lactante , Técnicas de Diagnóstico Molecular , Parechovirus/genética , Infecciones por Picornaviridae/diagnóstico , Infecciones por Picornaviridae/epidemiología , Sepsis/diagnóstico , Sepsis/epidemiología
7.
Rev Argent Microbiol ; 54(3): 209-214, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35012808

RESUMEN

We report a case of disseminated histoplasmosis and COVID-19 infection in a renal transplant recipient in Argentina. The patient exhibited respiratory symptoms, and a chest computed tomography scan (CT) showed multiple bilateral centrilobular opacities with a tree-in-bud pattern in both lobes. The patient was initially treated as having bacterial community-acquired pneumonia, and then tuberculosis. A month later, histoplasmosis was diagnosed, and Histoplasma capsulatum LAmB clade was isolated from sputum, skin and oral lesions. The patient was hospitalized and treatment was started with intravenous liposomal amphotericin B. During the course of the antifungal therapy the respiratory symptoms worsened, a new chest CT showed a unilateral lesion with a ground glass appearance and SARS-CoV-2 was detected in a new nasopharyngeal sample. In addition, plasma therapy was administered, and the immunosuppressive regimen was adjusted (everolimus was interrupted, mycophenolate mofetil reduced, and meprednisone increased). Finally, the patient's progress was favorable and was discharged after five days on oral itraconazole treatment for histoplasmosis.


Asunto(s)
COVID-19 , Histoplasmosis , Trasplante de Riñón , Anfotericina B/uso terapéutico , Antifúngicos/uso terapéutico , COVID-19/complicaciones , Everolimus , Histoplasma , Histoplasmosis/complicaciones , Histoplasmosis/tratamiento farmacológico , Itraconazol/uso terapéutico , Trasplante de Riñón/efectos adversos , Ácido Micofenólico , SARS-CoV-2
8.
Rev Argent Microbiol ; 54(3): 203-208, 2022.
Artículo en Español | MEDLINE | ID: mdl-33838969

RESUMEN

Trichophyton benhamiae is a zoonotic dermatophyte that can cause tinea corporis, tinea faciei and tinea capitis, producing inflammatory lesions, especially in children. In this publication, we describe 7clinical cases of pediatric patients that occurred in our institution between July 2019 and January 2020. All patients underwent a conventional mycological study. The identification of fungi isolates was confirmed by MALDI-TOF MS and sequencing of the ribosomal DNA. T. benhamiae was identified as the etiological agent, whose epidemiological link in all cases was the contact with Guinea pigs. This is the first description of infections caused by T. benhamiae in Argentina. This dermatophyte can be misidentified as other more frequent dermatophytes when performing conventional studies. Molecular technology should be used to reach a definitive diagnosis. It is important to have epidemiological data from patients such as contact with non-traditional pets, especially Guinea pigs, for an adequate presumptive diagnosis of this dermatophytosis.


Asunto(s)
Arthrodermataceae , Tiña , Animales , Argentina/epidemiología , Arthrodermataceae/genética , ADN Ribosómico , Cobayas , Tiña/diagnóstico , Tiña/epidemiología , Tiña/veterinaria , Trichophyton/genética
9.
Anaerobe ; 49: 14-17, 2018 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-29074149

RESUMEN

Thirty one C. difficile isolates recovered in 2015 were characterized. Nineteen/31 were positive for tcdA/B, among them, 4 isolates were also positive for CDT coding genes. Two/4 cdtA/B positives isolates corresponded to ST 1 resembling BI/NAP1/027/ST 1 strain, while the others corresponded to ST 226 and ST 377.


Asunto(s)
Clostridioides difficile/genética , Clostridioides difficile/aislamiento & purificación , Infecciones por Clostridium/microbiología , Enterotoxinas/genética , Anciano , Anciano de 80 o más Años , Argentina , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Preescolar , Clostridioides difficile/clasificación , Clostridioides difficile/metabolismo , Enterotoxinas/metabolismo , Femenino , Humanos , Masculino , Persona de Mediana Edad
10.
Rev Argent Microbiol ; 50(1): 36-44, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-28988901

RESUMEN

The best laboratory diagnostic approach to detect Clostridioides [Clostridium] difficile infection (CDI) is a subject of ongoing debate. With the aim of evaluating four laboratory diagnostic methods, 250 unformed stools from patients with suspected CDI submitted to nine medical center laboratories from November 2010 to December 2011, were studied using: (1) an immunochromatographic rapid assay test that combines the qualitative determination of glutamate dehydrogenase (GDH) plus toxins A and B (QAB), the CDIFF QUIK CHEK COMPLETE assay; (2) an enzyme immunoassay for qualitative determination of toxins A and B, the RIDASCREEN™ C. difficile Toxin A/B assay (RAB); (3) a PCR for the toxin B gene assay (PCR); and (4) the toxigenic culture (TC). C. difficile isolates from direct toxin negative stools by QAB, RAB and PCR were evaluated for toxigenicity by the same direct tests, in order to assess the contribution of the TC (QAB-TC, RAB-TC, PCR-TC). A combination of the cell culture cytotoxicity neutralization assay (CCCNA) in stools, and the same assay on isolates from direct negative samples (CCCNA-TC) was considered the reference method (CCCNA/CCCNA-TC). Of the 250 stools tested, 107 (42.8%) were positive by CCCNA/CCCNA-TC. The GDH and PCR/PCR-TC assays were the most sensitive, 91.59% and 87.62%, respectively. The QAB, RAB, QAB/QAB-TC and RAB/RAB-TC had the highest specificities, ca. 95%. A negative GDH result would rule out CDI, however, its low positive likelihood ratio (PLR) of 3.97 indicates that a positive result should always be complemented with the detection of toxins. If the RAB, QAB, and PCR assays do not detect toxins from direct feces, the toxigenic culture should be performed. In view of our results, the most accurate and reliable methods to be applied in a clinical microbiology laboratory were the QAB/QAB-TC, and RAB/RAB-TC, with PLRs >10 and negative likelihood ratios <0.30.


Asunto(s)
Toxinas Bacterianas , Clostridioides difficile , Técnicas para Inmunoenzimas , Reacción en Cadena de la Polimerasa , Proteínas Bacterianas , Toxinas Bacterianas/análisis , Clostridioides difficile/genética , Enterotoxinas , Heces , Humanos , Sensibilidad y Especificidad
11.
Rev Argent Microbiol ; 49(1): 7-14, 2017.
Artículo en Español | MEDLINE | ID: mdl-28189278

RESUMEN

In order to optimize the identification of molds with MALDI-TOF MS, three protein extraction-methodologies were evaluated against 44 isolates: water extraction (WE), zirconium extraction (ZE) and the provider's recommended method (PRM). Two data bases were compared, Bruker (BK) and Bruker+National Institutes of Health. Considering both databases, results were respectively as follows: correct identification (CI) at gender level, 10 and 16 by WE; 27 and 32 by ZE and 18 and 23 by PRM; CI at species level, 5 and 7 by WE; 17 and 20 by ZE and 11 and 14 by PRM; non-reliable identification, 18 and 12 by WE; 9 and 4 by ZE and by PRM. No peaks were observed in 16 by WE, 8 by ZE and 17 by PRM. ZE showed the best perfomance (p<0.05).


Asunto(s)
Hongos , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Bases de Datos Factuales , Hongos/aislamiento & purificación , Fase Preanalítica
12.
Anaerobe ; 33: 8-13, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25623818

RESUMEN

A prospective analysis on ß-lactam resistance mechanisms and ß-lactamase prevalence was conducted on Prevotella intermedia and Prevotella nigrescens recovered from patients with chronic periodontitis and peritonsillar abscesses. Both phenotypic and genotypic methods were performed to characterize the ß-lactamases, their coding genes and their genetic contexts. Overall, ß-lactamase production was observed in 64% (16/25) P. intermedia and 23.8% (5/21) P. nigrescens (p < 0.01). Besides higher ß-lactamase production rates were observed in P. intermedia (8/16) than in P. nigrescens (2/16) recovered from chronic periodontitis, almost all isolates from peritonsillar abscesses were producers (8/9 and 3/3, respectively). cfxA, but not cepA and cblA, was detected in those isolates, which were previously categorized as ß-lactamase producers. CfxA producing isolates displayed higher ß-lactam MICs than non-producers in both species. The most frequent allele was cfxA2, followed by cfxA3 and a new allelic variant named cfxA6. The analysis of the downstream flanking region in the three cfxA variants revealed the association with mobA of Tn4555, suggesting their localization in a mobilizable element. ß-lactam resistance and cfxA carriage prevalence seems to be not only related to the bacterial species but also to the infection site.


Asunto(s)
Infecciones por Bacteroidaceae/microbiología , Absceso Peritonsilar/microbiología , Prevotella intermedia/genética , Prevotella nigrescens/genética , beta-Lactamasas/genética , Antibacterianos/farmacología , Infecciones por Bacteroidaceae/epidemiología , Femenino , Orden Génico , Genotipo , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Absceso Peritonsilar/epidemiología , Prevalencia , Prevotella intermedia/efectos de los fármacos , Prevotella intermedia/aislamiento & purificación , Prevotella nigrescens/efectos de los fármacos , Prevotella nigrescens/aislamiento & purificación , Estudios Prospectivos , Resistencia betalactámica
13.
Rev Argent Microbiol ; 47(1): 50-3, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25681265

RESUMEN

Community-acquired methicillin-resistant Staphylococcus aureus is the first cause of skin and soft tissue infections, but can also produce severe diseases such as bacteremia, osteomyelitis and necrotizing pneumonia. Some S. aureus lineages have been described in cases of necrotizing pneumonia worldwide, usually in young, previously healthy patients. In this work, we describe a fatal case of necrotizing pneumonia due to community-acquired methicillin-resistant S. aureus clone ST30-SCCmecIVc-spat019-PVL positive in an immunocompetent adult patient.


Asunto(s)
Staphylococcus aureus Resistente a Meticilina , Neumonía Bacteriana/microbiología , Infecciones Estafilocócicas/microbiología , Argentina , Infecciones Comunitarias Adquiridas/patología , Resultado Fatal , Humanos , Masculino , Staphylococcus aureus Resistente a Meticilina/clasificación , Persona de Mediana Edad , Necrosis , Neumonía Bacteriana/patología , Infecciones Estafilocócicas/patología
14.
J Clin Microbiol ; 52(9): 3483-5, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-25031447

RESUMEN

KPC-2-producing Klebsiella pneumoniae isolates mainly correspond to clonal complex 258 (CC258); however, we describe KPC-2-producing K. pneumoniae isolates belonging to invasive sequence type 23 (ST23). KPC-2 has scarcely been reported to occur in ST23, and this report describes the first isolation of this pathogen in the Americas. Acquisition of resistant markers in virulent clones could mark an evolutionary step toward the establishment of these clones as major nosocomial pathogens.


Asunto(s)
Infecciones por Klebsiella/diagnóstico , Infecciones por Klebsiella/microbiología , Klebsiella pneumoniae/clasificación , Klebsiella pneumoniae/aislamiento & purificación , Tipificación Molecular , beta-Lactamasas/metabolismo , Anciano de 80 o más Años , Américas , Técnicas Bacteriológicas , Evolución Molecular , Orden Génico , Genes Bacterianos , Genotipo , Humanos , Klebsiella pneumoniae/genética , Masculino , beta-Lactamasas/genética
15.
Pathogens ; 12(7)2023 Jun 22.
Artículo en Inglés | MEDLINE | ID: mdl-37513712

RESUMEN

Carbapenemase resistance in Enterobacterales is a global public health problem and rapid and effective methods for detecting these resistance mechanisms are needed urgently. Our aim was to evaluate the performance of a MALDI-TOF MS-based "Klebsiella pneumoniae carbapenemase" (KPC) detection protocol from patients' positive blood cultures, short-term cultures, and colonies in healthcare settings. Bacterial identification and KPC detection were achieved after protein extraction with organic solvents and target spot loading with suitable organic matrices. The confirmation of KPC production was performed using susceptibility tests and blaKPC amplification using PCR and sequencing. The KPC direct detection (KPC peak at approximately 28.681 Da) from patients' positive blood cultures, short-term cultures, and colonies, once bacterial identification was achieved, showed an overall sensibility and specificity of 100% (CI95: [95%, 100%] and CI95: [99%, 100%], respectively). The concordance between hospital routine bacterial identification protocol and identification using this new methodology from the same extract used for KPC detection was ≥92%. This study represents the pioneering effort to directly detect KPC using MALDI-TOF MS technology, conducted on patient-derived samples obtained from hospitals for validation purposes, in a multi-resistance global context that requires concrete actions to preserve the available therapeutic options and reduce the spread of antibiotic resistance markers.

16.
J Glob Antimicrob Resist ; 32: 85-87, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36368600

RESUMEN

OBJECTIVES: The emergence of blaKPC-2 within nosocomial settings has become a major public health crisis worldwide. Our aim was to perform whole-genome sequencing (WGS) of three KPC-producing Gram-negative bacilli (KPC-GNB) strains isolated from a hospitalized patient to identify acquired antimicrobial resistance genes (ARGs). METHODS: WGS was performed using Illumina MiSeq-I, and de novo assembly was achieved using SPAdes. Bioinformatics analysis was done using Resfinder, AMRFinder, ISFinder, plasmidSPAdes, PlasmidFinder, MOB-suite, PLSDB database, and IntegronFinder. Conjugation assays were performed to assess the ability of blaKPC-2 to transfer via a plasmid-related mobilization mechanism. RESULTS: High-risk clone KPC-producing Klebsiella pneumoniae sequence type (ST) 258 (HA3) was colonizing an inpatient who later was infected by KPC-producing Escherichia coli ST730 (HA4) and subsequently by KPC-producing K. pneumoniae ST11 (HA15) during hospitalization. Although belonging to different species, both strains causing infections harbored the same gene configuration for dissemination of blaKPC-2 in related IncM1 plasmids recently found in other KPC-GNB isolated from Hospital Alemán at Ciudad Autónoma de Buenos Aires. Conjugation assays revealed that only pDCVEA4-KPC from E. coli HA4 was successfully transferred with a conjugation frequency of 3.66 × 101. CONCLUSIONS: Interchange of multidrug-resistant K. pneumoniae lineages ST258 replaced by ST11 in the framework of colonization and infection by KPC-GNB of an inpatient from our institution was found. In addition, the transfer of the gene configuration of blaKPC-2 between infecting strains may have occurred in the nosocomial environment, but we cannot rule out that the event took place in vivo, within the patient, during hospitalization.


Asunto(s)
Infección Hospitalaria , Infecciones por Klebsiella , Humanos , Antibacterianos/farmacología , beta-Lactamasas/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Pandemias , Pacientes Internos , Infecciones por Klebsiella/epidemiología , Farmacorresistencia Bacteriana , Plásmidos/genética , Klebsiella pneumoniae , Hospitalización , Infección Hospitalaria/epidemiología
17.
RSC Adv ; 13(39): 27391-27402, 2023 Sep 08.
Artículo en Inglés | MEDLINE | ID: mdl-37711381

RESUMEN

We present herein an in-depth study on the activity of amidinoquinoxaline N-oxides 1 against Gram-positive and Gram-negative anaerobic bacteria. Based on 5-phenyl-2,3-dihydropyrimidoquinoxaline N-oxide 1a, the selected structural variations included in our study comprise the substituents α- to the N-oxide function, the benzofused ring, substitution and quaternization of the amidine moiety, and the amidine ring size. Compounds 1 showed good to excellent antianaerobic activity, evaluated as the corresponding CIM50 and CIM90 values, and an antimicrobial spectrum similar to metronidazole. Six out of 13 compounds 1 had CIM90 values significantly lower than the reference drug. Among them, imidazoline derivatives 1i-l were the most active structures. Such compounds were synthesized by base-promoted ring closure of the corresponding amidines. The N-oxides under study showed no significant cytotoxicity against RAW 264.7 cells, with high selectivity indexes. Their calculated ADME properties indicate that the compounds are potentially good oral drug candidates. The antianaerobic activity correlated satisfactorily with the electron affinity of the compounds, suggesting that they may undergo bioreductive activation before exerting their antibacterial activity.

18.
J Glob Antimicrob Resist ; 32: 108-112, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36708770

RESUMEN

OBJECTIVES: The worldwide dissemination of carbapenemase-producing Escherichia coli lineages belonging to high-risk clones poses a challenging public health menace. The aim of this work was to investigate genomic features of a colonizing multidrug-resistant strain of Klebsiella pneumoniae carbapenemase (KPC)-producing E. coli from our institution. METHODS: Whole-genome sequencing was done by Illumina MiSeq-I, and de novo assembly was achieved using SPAdes. Resistome, mobilome, plasmids, virulome, and integrons were analysed using ResFinder, AMRFinder, ISFinder, PlasmidFinder, MOB-suite, VirulenceFinder, and IntegronFinder. Sequence types (STs) were identified with pubMLST and BIGSdb databases. Conjugation assays were also performed. RESULTS: Escherichia coli HA25pEc was isolated from a rectal swab sample taken within the framework of the hospital epidemiological surveillance protocol for detection of carbapenemase-producing Enterobacterales. Escherichia coli HA25pEc corresponded to the first report of ST648 co-harbouring blaKPC-2 and blaCTX-M-15 in Latin America from a colonized patient. It had 19 antibiotic resistance genes (ARGs), including blaKPC-2, located on a Tn4401a isoform. Conjugation assays revealed that blaKPC-2 was not transferred by conjugation to E. coli J53 under our experimental conditions. CONCLUSION: Escherichia coli ST648 has been detected previously in companion and farm animals as well as in hospital- and community-acquired infections worldwide. Although scarcely reported as KPC-producers, our finding in a culture surveillance with several acquired ARGs, including blaCTX-M-15, alerts the potential of this clone for worldwide unnoticed spreading of extreme drug resistance to ß-lactams. These data reinforce the importance of carrying out molecular surveillance to identify reservoirs and warn about the dissemination of new international clones in carbapenemase-bearing patients.


Asunto(s)
Farmacorresistencia Bacteriana Múltiple , Escherichia coli , Escherichia coli/genética , Farmacorresistencia Bacteriana Múltiple/genética , beta-Lactamasas/genética , Antibacterianos/farmacología , Klebsiella pneumoniae , Genómica , Hospitales
19.
Antimicrob Agents Chemother ; 56(3): 1309-14, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22232282

RESUMEN

The antibiotic susceptibility rates of 363 clinical Bacteroides fragilis group isolates collected from 17 centers in Argentina during the period from 2006 to 2009 were as follows: piperacillin-tazobactam, 99%; ampicillin-sulbactam, 92%; cefoxitin, 72%; tigecycline, 100%; moxifloxacin, 91%; and clindamycin, 52%. No metronidazole resistance was detected in these isolates during this time period. Resistance to imipenem, doripenem, and ertapenem was observed in 1.1%, 1.6%, and 2.3% of B. fragilis group strains, respectively. B. fragilis species showed a resistance profile of 1.5% to imipenem, 1.9% to doripenem, and 2.4% to ertapenem. This is the first report of carbapenem resistance in Argentina. The cfiA gene was present in 8 out of 23 isolates, all of them belonging to the B. fragilis species and displaying reduced susceptibility or resistance to carbapenems (MICs ≥ 4 µg/ml). Three out of eight cfiA-positive isolates were fully resistant to carbapenems, while 5 out of 8 isolates showed low-level resistance (MICs, 4 to 8 µg/ml). The inhibition by EDTA was a good predictor of the presence of metallo-ß-lactamases in the fully resistant B. fragilis strains, but discrepant results were observed for low-level resistant isolates. B. fragilis was more susceptible to antimicrobial agents than other Bacteroides species. Bacteroides vulgatus species was the most resistant to ampicillin-sulbactam and piperacillin-tazobactam, and B. thetaiotaomicron/ovatus strains showed the highest level of resistance to carbapenems, with an unknown resistance mechanism. B. vulgatus and the uncommon non-Bacteroides fragilis species were the most resistant to moxifloxacin, showing an overall resistance rate of 15.1%.


Asunto(s)
Antibacterianos/administración & dosificación , Infecciones por Bacteroides/tratamiento farmacológico , Bacteroides fragilis/efectos de los fármacos , Bacteroides/efectos de los fármacos , Carbapenémicos/administración & dosificación , Resistencia betalactámica/genética , Argentina/epidemiología , Proteínas Bacterianas/genética , Bacteroides/crecimiento & desarrollo , Bacteroides/aislamiento & purificación , Infecciones por Bacteroides/epidemiología , Infecciones por Bacteroides/microbiología , Bacteroides fragilis/crecimiento & desarrollo , Bacteroides fragilis/aislamiento & purificación , Líquidos Corporales/microbiología , Estudios Transversales , Ácido Edético/farmacología , Femenino , Humanos , Estudios Longitudinales , Masculino , Pruebas de Sensibilidad Microbiana , Vigilancia de la Población , Resistencia betalactámica/efectos de los fármacos , beta-Lactamasas/genética
20.
Ann Clin Microbiol Antimicrob ; 11: 29, 2012 Oct 22.
Artículo en Inglés | MEDLINE | ID: mdl-23088592

RESUMEN

BACKGROUND: The Tigecycline Evaluation and Surveillance Trial (T.E.S.T.) is a global surveillance study of antimicrobial susceptibility. This study reports data from Gram-negative isolates collected from centers in Latin America between 2004 and 2010. METHODS: Consecutive bacterial isolates were tested at each center using broth microdilution methodology as described by the Clinical Laboratory Standards Institute (CLSI). Susceptibility was determined using the CLSI interpretive criteria. For tigecycline the US Federal Drug Administration (FDA) criteria were used. RESULTS: A total of 16 232 isolates were analyzed. Susceptibility to imipenem, meropenem, and tigecycline was >95% against both non-extended-spectrum ß-lactamase (ESBL) and ESBL producing Escherichia coli. Susceptibility to amikacin was also >95% for non-ESBL E. coli. 24.3% of E. coli were ESBL producers, ranging from 11.2% (58/519) in Colombia to 40.3% (31/77) in Honduras. Greater than 90% of non-ESBL Klebsiella pneumoniae were susceptible to tigecycline, carbapenems and amikacin. 35.3% of K. pneumoniae were ESBL producers, ranging from 17.2% (36/209) in Venezuela to 73.3% (55/75) in Honduras, with only imipenem and tigecycline maintaining >90% susceptibility. Greater than 90% of Klebsiella oxytoca, Enterobacter spp., and Serratia marcescens were susceptible to amikacin, carbapenems and tigecycline. The highest rates of susceptibility against Acinetobacter baumannii were seen for minocycline (89.4%) and imipenem (62.5%), while 95.8% of the A. baumannii isolates displayed an MIC≤2 µg/mL for tigecycline. CONCLUSIONS: In this study carbapenems and tigecycline remain active against Enterobacteriaceae and A. baumannii; however, there is cause for concern with carbapenem non-susceptible isolates reported in all countries included in this study.


Asunto(s)
Antibacterianos/farmacología , Farmacorresistencia Bacteriana Múltiple , Minociclina/análogos & derivados , Acinetobacter baumannii/efectos de los fármacos , Acinetobacter baumannii/aislamiento & purificación , Amicacina/farmacología , Carbapenémicos/farmacología , Enterobacter/efectos de los fármacos , Enterobacter/aislamiento & purificación , Escherichia coli/efectos de los fármacos , Escherichia coli/aislamiento & purificación , Escherichia coli/metabolismo , Imipenem/farmacología , Klebsiella oxytoca/efectos de los fármacos , Klebsiella oxytoca/aislamiento & purificación , Klebsiella pneumoniae/efectos de los fármacos , Klebsiella pneumoniae/aislamiento & purificación , América Latina , Meropenem , Pruebas de Sensibilidad Microbiana , Minociclina/farmacología , Serratia marcescens/efectos de los fármacos , Serratia marcescens/aislamiento & purificación , Tienamicinas/farmacología , Tigeciclina , Estados Unidos , United States Food and Drug Administration , beta-Lactamasas/farmacología
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