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1.
Zhonghua Shao Shang Za Zhi ; 36(1): 24-31, 2020 Jan 20.
Artículo en Chino | MEDLINE | ID: mdl-32023714

RESUMEN

Objective: To analyze the distribution and drug resistance of pathogens isolated from patients with catheter-related bloodstream infection (CRBSI) in burn intensive care unit (BICU). Methods: From January 2011 to December 2018, among 2 264 patients who were peripherally inserted central venous catheter at the BICU of the First Affiliated Hospital of Army Medical University (the third Military Medical University), hereinafter referred to as the author's unit, 159 patients were diagnosed CRBSI, including 131 males and 28 females, aged 43 (1, 79) years. The pathogens primarily isolated from peripheral venous blood and central venous catheter blood/anterior central venous catheter specimen of patients with CRBSI were retrospectively analyzed. API bacteria identification kits and automatic microorganism identification instrument were used to identify pathogens. Broth micro-dilution method or Kirby-Bauer paper disk diffusion method was used to detect the drug resistance of the pathogens to 5 antifungal drugs including fluconazole and itraconazole, etc., and 37 antibacterial drugs including tigecycline and imipenem, etc. Modified Hodge test was used to further identify imipenem- and meropenem-resistant Klebsiella pneumonia. D test was used to detect erythromycin-induced clindamycin resistant Staphylococcus aureus. The WHONET 5.6 software was applied to analyze the annual incidence of CRBSI, mortality of patients with CRBSI, incidence of CRBSI cases, distribution of infection site, and duration of catheterization, detection of Gram-negative and Gram-positive bacteria, fungi, methicillin-resistant Staphylococcus aureus (MRSA), and methicillin-sensitive Staphylococcus aureus (MSSA), and drug resistance of fungi and major Gram-negative and Gram-positive bacteria to the commonly used antibiotics in clinic. Results: (1) The incidence of CRBSI was 7.0% (159/2 264) during the eight years, which was slightly higher in 2014 and 2017 with 13.6% (30/221) and 11.1% (24/217) respectively. The mortality rate of patients with CRBSI was 7.5% (12/159). (2) The incidence of CRBSI cases was 14.9% (338/2 264); the main infection site was femoral vein, totally 271 cases (80.2%), and the duration of catheterization of this site was 9 (2, 25) d. (3) During the eight years, totally 543 strains of pathogens were isolated, including 353 (65.0%) strains of Gram-negative bacteria, 140 (25.8%) strains of Gram-positive bacteria, and 50 (9.2%) strains of fungi. The top three isolated pathogens with isolation rate from high to low were Acinetobacter baumannii, Staphylococcus aureus, and Pseudomonas aeruginosa, accounting for 23.2% (126/543), 17.1% (93/543), and 15.7% (85/543), respectively. Fungi were mainly Candida parapsilosis. Among the Staphylococcus aureus, the detection rate of MRSA was 98.9% (92/93), and that of MSSA was 1.1% (1/93). (4) Except for the low drug resistance rates to polymyxin B, minocycline, and tigecycline, the drug resistance rates of Acinetobacter baumannii to the other antibiotics were considerably high (80.1%-100.0%). Pseudomonas aeruginosa was not resistant to polymyxin B but highly resistant to netilmicin (88.7%) and piperacillin (92.6%), with resistance rates to the other antibiotics from 34.5% to 62.7%. Klebsiella pneumoniae was not resistant to tigecycline and lowly resistant to imipenem and meropenem (28.9%, 9 imipenem- and meropenem-resistant strains were further confirmed by modified Hodge test), with resistance rates to the other antibiotics from 40.9% to 95.2%. The resistance rates of MRSA to most antibiotics were higher than those of MSSA. MRSA was not resistant to linezolid, vancomycin, teicoplanin, sulfamethoxazole, or tigecycline. The resistance rates of MRSA to clindamycin and erythromycin were 7.9% and 62.0%, respectively, and those to the other antibiotics were higher than 91.5%. Except for the complete resistance to penicillin G and tetracycline, MSSA was not resistant to the other antibiotics. Thirty-three strains of Staphylococcus aureus showed resistance to erythromycin-induced clindamycin. Fungi was not resistant to amphotericin B, with drug resistance rates to voriconazole, itraconazole, ketoconazole, and fluconazole from 4.2% to 6.2%. Conclusions: The incidence of CRBSI and mortality of patients with CRBSI are high in BICU of the author's unit, and the main infection site is femoral vein. There are various types of pathogens in patients with CRBSI, and most of them are Gram-negative. The top three isolated pathogens are Acinetobacter baumannii, Staphylococcus aureus, and Pseudomonas aeruginosa, accompanying with grim drug resistance phenomenon.


Asunto(s)
Bacteriemia , Staphylococcus aureus Resistente a Meticilina , Adolescente , Adulto , Anciano , Antibacterianos , Niño , Preescolar , Resistencia a Medicamentos , Farmacorresistencia Bacteriana , Femenino , Humanos , Lactante , Unidades de Cuidados Intensivos , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Estudios Retrospectivos , Adulto Joven
2.
Appl Microbiol Biotechnol ; 104(5): 1955-1976, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31970432

RESUMEN

Aminoglycosides are one of the common classes of antibiotics that have been widely used for treating infections caused by pathogenic bacteria. The mechanism of bactericidal action by aminoglycosides is well-known, by which it terminates the cytoplasmic protein synthesis. However, the potentials of aminoglycosides become hindered when facing the evolution of bacterial resistance mechanisms. Among multiple resistance mechanisms displayed by bacteria against antibiotics, the formation of biofilm is the mechanism that provides a barrier for antibiotics to reach the cellular level. Bacteria present in the biofilm also get protection against the impact of host immune responses, harsh environmental conditions, and other antimicrobial treatments. Hence, with the multifaceted resistance developed by biofilm-forming pathogenic bacteria, antibiotics are therefore discontinued for further applications. However, the recent research developed several alternative strategies such as optimization of the active concentration, modification of the environmental conditions, modification of the chemical structure, combinatorial application with other active agents, and formulation with biocompatible carrier materials to revitalize and exploit the new potential of aminoglycosides. The present review article describes the above mentioned multiple approaches and possible mechanisms for the application of aminoglycosides to treat biofilm-associated infections.


Asunto(s)
Aminoglicósidos/farmacología , Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Biopelículas/efectos de los fármacos , Adyuvantes Farmacéuticos/química , Adyuvantes Farmacéuticos/farmacología , Adyuvantes Farmacéuticos/uso terapéutico , Aminoglicósidos/química , Aminoglicósidos/uso terapéutico , Antibacterianos/química , Antibacterianos/uso terapéutico , Bacterias/crecimiento & desarrollo , Bacterias/patogenicidad , Infecciones Bacterianas/tratamiento farmacológico , Biopelículas/crecimiento & desarrollo , Portadores de Fármacos/química , Portadores de Fármacos/farmacología , Portadores de Fármacos/uso terapéutico , Farmacorresistencia Bacteriana , Quimioterapia Combinada , Humanos , Factores de Virulencia/metabolismo
3.
Euro Surveill ; 25(3)2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31992391

RESUMEN

From September to October 2019, seven patients colonised or infected with a ceftazidime-avibactam (CZA)-resistant Klebsiella pneumoniae carbapenemase (KPC)-2-producing K. pneumoniae were detected in two intensive care units of a Greek general hospital. The outbreak strain was sequence type (ST)147 and co-produced KPC-2 and the novel plasmid-borne Vietnamese extended-spectrum ß-lactamase (VEB)-25 harbouring a K234R substitution associated with CZA resistance. Epidemiological investigations revealed that the resistance was probably acquired by horizontal transmission independently from previous CZA exposure.


Asunto(s)
Antibacterianos/farmacología , Infecciones por Klebsiella/microbiología , Klebsiella pneumoniae/genética , beta-Lactamasas/genética , beta-Lactamasas/metabolismo , Anciano , Anciano de 80 o más Años , Compuestos de Azabiciclo , Ceftazidima , Brotes de Enfermedades , Combinación de Medicamentos , Farmacorresistencia Bacteriana , Femenino , Genoma Bacteriano , Grecia , Humanos , Unidades de Cuidados Intensivos , Klebsiella pneumoniae/efectos de los fármacos , Klebsiella pneumoniae/enzimología , Klebsiella pneumoniae/aislamiento & purificación , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Mutación/genética , Secuenciación Completa del Genoma
4.
Mymensingh Med J ; 29(1): 37-42, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31915333

RESUMEN

Uropathogenic Escherichia coli is frequently resistant to different antibiotic leading to a critical condition of the patients. The purpose of the present study was to see antibiotic resistance pattern and genetic characteristics of ESBL and Carbapenemase-producing Escherichia coli. This cross sectional study was conducted in the Department of Microbiology at Mymensingh Medical College, Mymensingh, Bangladesh from October 2014 to December 2015. Patients presented with clinically diagnosed urinary tract infection at any age with both sexes who attended in the OPD of Mymensingh Medical College Hospital and the Doctors Diagnostic Centre in Mymensingh, Bangladesh was selected as study population. Non duplicate clinical isolates from urine were collected in full aseptic precaution for culture of bacteria. Escherichia coli were confirmed by PCR Stargetingadk. Antimicrobial susceptibility was measured by broth microdilution test. Minimum inhibitory concentrations against 18 antimicrobial agents were measured. Beta-lactamase genes were detected by multiplex PCR. For all the isolates showing resistance to imipenem and/or meropenem, presence of carbapenemase genes was confirmed by multiplex/uniplex PCR using primers. A total of 233 non-duplicate clinical isolates of Escherichia coli were collected from patients of which dominant phylogenetic group was B2 which was 78(33.5%) isolates of which 71 isolates were B2a and 7 isolates were B2b. Furthermore, Group A was in 29.6% isolates and Group D was in 26.6% isolates. E. coli showed significantly higher resistance rates to piperacillin, cephalosporins, and some other antimicrobials. Meropenem-resistance was detected in 8.2% of E. coli. The detection rate of blaTEM was 41.6% in E. coli. Carbapenemase genes were detected in 9(3.9%) isolates of E. coli and identified as genes encoding NDM-1, -5, and 7 and OXA-181. All the blaNDM-positive E. coli isolates carried also blaCTX-M-15, except for a group B1 isolate. E. coli is significantly higher resistance rates to piperacillin, cephalosporins, and some other antimicrobials and possesses different ESBL and carbapenemase genes.


Asunto(s)
Antibacterianos/farmacología , Proteínas Bacterianas/genética , Farmacorresistencia Bacteriana/genética , Infecciones por Escherichia coli/tratamiento farmacológico , Escherichia coli/genética , beta-Lactamasas/genética , Bangladesh , Estudios Transversales , Escherichia coli/clasificación , Escherichia coli/efectos de los fármacos , Escherichia coli/enzimología , Infecciones por Escherichia coli/microbiología , Femenino , Genes Bacterianos , Humanos , Masculino , Pruebas de Sensibilidad Microbiana/métodos , Filogenia , Reacción en Cadena de la Polimerasa , Centros de Atención Terciaria , beta-Lactamasas/metabolismo
7.
J Zoo Wildl Med ; 50(4): 813-821, 2020 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-31926511

RESUMEN

Accredited zoos and animal parks play an important role in animal health research and conservation, providing important insights on matters of public health including zoonotic infectious diseases and antimicrobial resistance (AMR). The emergence and spread of AMR is a complex phenomenon that jeopardizes human and animal health and also threatens the long-term survival of endangered species. The presence of ß-lactamases in clinical isolates is particularly significant as they can jeopardize the efficacy of critically important antimicrobials. Although the presence of ß-lactamases and extended-spectrum ß-lactamases (ESBLs) producing Enterobacteriaceae in zoo animals has been reported, data are not available for northern European countries. In addition, few data are available on phylogenetic grouping of Escherichia coli isolated from zoo animals that can provide additional information on the host-bacterium relationship and on the pathogenicity of isolates. This study aimed to characterize fecal E. coli isolated from 33 healthy zoo animals from 22 species in Ireland, using conventional and molecular microbiological methods. All E. coli isolates were ampicillin resistant, but combined resistance to amoxicillin and clavulanic acid was not detected. Three E. coli isolates sampled from one Amur tiger, one Bornean orangutan, and one Southern white rhino were multidrug resistant, and blaTEM was detected in E. coli recovered from the Amur tiger and the Bornean orangutan. Other ß-lactamases, including ESBLs and AmpCs and plasmid-mediated mcr-1 and mcr-2, were not detected. Overall, E. coli isolates investigated were susceptible to the majority of the antimicrobials tested, and only two animals shed E. coli carrying ß-lactamase-encoding genes. The majority of isolates belonged to phylogenetic group B1. The screening of the AMR phenotype and genotype of zoo animal E. coli provides useful data that is relevant to antimicrobial stewardship in the zoo veterinary services and relevant to the bank of knowledge needed for tackling AMR.


Asunto(s)
Animales de Zoológico , Escherichia coli/efectos de los fármacos , Escherichia coli/aislamiento & purificación , Heces/microbiología , Animales , Antibacterianos/farmacología , Farmacorresistencia Bacteriana , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Regulación Bacteriana de la Expresión Génica/fisiología , Filogenia
8.
Fitoterapia ; 140: 104433, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31760066

RESUMEN

Antibiotics, considered as a backbone of modern clinical-medicines, are facing serious threats from emerging antimicrobial-resistance (AMR) in several bacteria from nosocomial and community origins and is posing a serious human-health concern. Recent commitment by the Heads of States at the United Nations General Assembly (UNGA, 2016) for coordinated efforts to curb such infections illustrates the scale of this problem. Amongst the drug-resistant microbes, major threat is posed by the group named as ESKAPEE, an acronym for Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp., and Escherichia coli, comprising high to critical drug-resistant, World Health Organization Critical Priority I and II pathogens. The drying pipeline of effective and new antibiotics has worsened the situation with looming threat of heading to a 'post-antibiotic era'. This necessitates novel and effective approaches to combat this life-threatening issue. Medicinal and aromatic plants are hailed as the reservoir of bioactive compounds and can serve as a source of antimicrobial compounds, and some recent leads show that essential oils (EOs) may provide an effective solution for tackling AMR. EOs have shown wide-spectrum antimicrobial potentials via targeting the major determinants of pathogenicity, drug-resistance and its spread including cell membrane, drug efflux pumps, quorum sensing, biofilms and R-plasmids. Latest reports confirm the EOs having strong direct-killing or re-sensitizing potentials to replace or rejuvenate otherwise fading antibiotics arsenal. We discuss herein possibilities of using EOs directly for antimicrobial potentials or in combination with antibiotics to potentiate the later for combating AMR in ESKAPEE pathogens. The current understandings, success stories and challenges for translational success have also been discussed.


Asunto(s)
Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Farmacorresistencia Bacteriana , Aceites Volátiles/farmacología , Aceites Vegetales/farmacología , Infecciones Bacterianas/tratamiento farmacológico , Humanos
9.
Arch Virol ; 165(1): 97-104, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31734749

RESUMEN

Carbapenem-resistant Klebsiella pneumoniae (CRKP) has spread globally and emerged as an urgent public health threat. Bacteriophages are considered an effective weapon against multidrug-resistant pathogens. In this study, we report a novel lytic phage, kpssk3, which is able to lyse CRKP and degrade exopolysaccharide (EPS). The morphological characteristics of kpssk3 observed by transmission electron microscopy, including a polyhedral head and a short tail, indicate that it belongs to the family Podoviridae. A one-step growth curve revealed that kpssk3 has a latent period of 10 min and a burst size of 200 plaque-forming units (pfu) per cell. kpssk3 was able to lyse 25 out of 27 (92.59%) clinically isolated CRKP strains, and it also exhibited high stability to changes in temperature and pH. kpssk3 has a linear dsDNA genome of 40,539 bp with 52.80% G+C content and 42 putative open reading frames (ORFs). No antibiotic resistance genes, virulence factors, or integrases were identified in the genome. Based on bioinformatic analysis, the tail fiber protein of phage kpssk3 was speculated to possess depolymerase activity towards EPS. By comparative genomics and phylogenetic analysis, it was determined that kpssk3 is a new T7-like virus and belongs to the subfamily Autographivirinae. The characterization and genomic analysis of kpssk3 will promote our understanding of phage biology and diversity and provide a potential strategy for controlling CRKP infection.


Asunto(s)
Farmacorresistencia Bacteriana , Klebsiella pneumoniae/virología , Podoviridae/clasificación , Secuenciación Completa del Genoma/métodos , Composición de Base , Carbapenémicos , Genoma Viral , Concentración de Iones de Hidrógeno , Lisogenia , Microscopía Electrónica de Transmisión , Filogenia , Podoviridae/genética , Podoviridae/fisiología , Termodinámica , Proteínas de la Cola de los Virus/genética
10.
Arch Microbiol ; 202(1): 115-125, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31501949

RESUMEN

Staphylococcus aureus is part of the normal flora of animals, and represents one of the leading causes of contagious mastitis in dairy herds worldwide. Sixty-seven epidemiologically unrelated S. aureus isolates from nasal and mastitis milk samples of dairy-producing animals (32 cows, 25 sheep, and 10 goats) were characterized by antimicrobial susceptibility testing and spa typing followed by multilocus sequence typing (MLST) on representative isolates and SCCmec-typing on methicillin-resistant S. aureus (MRSA) isolates. The highest resistance was observed to penicillin (64.2%, 43/67), followed by tetracycline (23.9%, 16/67), erythromycin (22.4%, 15/67), and streptomycin (17.9%, 12/67). In general, 18 spa types (including newly identified t16958) and 13 sequence types (STs) belonging to 8 clonal complexes (CCs) were detected. The cow-associated isolates were mainly assigned to CC5 (n = 18, related to t267-ST97, t521-ST352, t527-ST97, t304-ST6, and t084-ST15), followed by CC398 (n = 6, t937-ST291), CC45 (n = 3, t230-ST45), CC88 (n = 2, t2526-ST88), CC22 (n = 2, t3680-ST22), and CC522 (n = 1, t3576-ST522). Small ruminant isolates were mostly clustered into CC522 (n = 29, related to t3576, t1534, t16958, t7308, t7311, t7305 [ST522], t1534-ST2057, and t5428-ST2079). Two isolates from cows with mastitis were found to be MRSA, exhibited a composite profile of t937-ST291-SCCmecIV. No isolates carried the PVL and mecC genes. A significant difference in clonal types of S. aureus isolates from cows in comparison with those from small ruminants was found. This study demonstrated the circulation of diverse clones of S. aureus among dairy animals in Iran, with a different clonal composition between cows and small ruminants. The current study also reports MRSA-related mastitis in dairy cows, emphasizing the need for comprehensive surveillance.


Asunto(s)
Antibacterianos/farmacología , Genotipo , Pruebas de Sensibilidad Microbiana/veterinaria , Rumiantes/microbiología , Infecciones Estafilocócicas/veterinaria , Staphylococcus aureus/efectos de los fármacos , Animales , Bovinos , Industria Lechera , Farmacorresistencia Bacteriana/efectos de los fármacos , Femenino , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Tipificación de Secuencias Multilocus , Ovinos , Infecciones Estafilocócicas/microbiología
11.
Food Microbiol ; 85: 103295, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31500701

RESUMEN

Fermented red pepper (FRP) sauce has been eaten in worldwide for many years. The salt content and resident microbial community influences the quality of the FRP sauce and may confer health (e.g., probiotics) or harm (e.g., antibiotic resistance genes) to the consumers in some circumstances; however, the salt-mediated alteration of microbial community and antibiotic resistance genes are little known. In this study, a combination of whole genome sequencing and amplicon analysis was used to investigate the changes in microbial community and antimicrobial resistance genes in response to different salt content during red pepper fermentation. While the family Enterobacteriaceae dominated in high-salt (15-25%) samples, Lactobacillaceae quickly became the dominant population in place of Enterobacteriaceae after 24 days in 10% salt samples. Compared to 0.05 antibiotic resistance genes (ARGs) per cell number on average in 10% salt sample, 16.6 ARGs were present in high-salt samples, wherein the bacterial hosts were major assigned to Enterobacteriaceae including genera Enterobacter, Citrobacter, Escherichia, Salmonella and Klebsiella. Multidrug resistance genes were the predominant ARG type. Functional profiling showed that histidine kinase functions were of much higher abundance in high-salt samples and included several osmotic stress-related two-component systems that simultaneously encoded ARGs. These results give first metagenomic insights into the salt-mediated changes in microbial community composition and a broad view of associated antibiotic resistance genes in the process of food fermentation.


Asunto(s)
Capsicum/química , Farmacorresistencia Bacteriana/genética , Enterobacteriaceae/genética , Lactobacillaceae/genética , Metagenoma , Microbiota , Cloruro de Sodio/química , Enterobacteriaceae/crecimiento & desarrollo , Fermentación , Genes Bacterianos , Lactobacillaceae/crecimiento & desarrollo , Metagenómica , Presión Osmótica
12.
Sci Total Environ ; 700: 134446, 2020 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-31648121

RESUMEN

Bacteriophage may play an important role in antimicrobial resistance genes (ARGs) transmission. However, the contribution of bacteriophage to the spread of ARGs in environment, especially in poultry farm environment, is rarely known. In this study, the prevalence of ARGs in bacteriophage DNA was investigated in chicken feces from 30 different poultry farms in China. Then the abundance of the aac(6')-Ib-cr, blaCTX-M, ermB, floR, mcr-1, sul1, tetM and intI1 genes was determined by qPCR in bacteriophage and compared with certain representative plasmid DNA samples. The results showed that 12 ARGs (aac(6')-Ib-cr, aph(3')-IIIa, blaCTX-M, ermB, ermF, floR, mcr-1, qnrS, sul1, sul2, vanA, tetM genes) and class 1 integron gene intI1 were detected in bacteriophage DNA fraction. The sul1, tetM and aac(6')-Ib-cr genes were most prevalent with high detection rates of 77%, 61% and 55%, respectively. To our best knowledge, this study firstly reported the presence of the mcr-1 gene in bacteriophage DNA derived from farms environments. We found that the gene copy (GC) numbers of the aac(6')-Ib-cr, ermB and sul1 genes were as high as 5.47, 5.22 and 5.54 log10 GC/g, respectively. Both the prevalence and abundance of ARGs in broiler fecal wastes were also generally higher than in laying hens. In addition, although the GC numbers of the aac(6')-Ib-cr, floR and tetM genes in plasmid DNA was higher than that in phage DNA fraction by 4.68, 3.59 and 3.9 orders of magnitude, respectively, the absolute abundances of the blaCTX-M and mcr-1 genes in phage DNA were close to or even higher than that in plasmid DNA at farm SIL2, SIL4 and SIB1. As potential vessels for ARGs, bacteriophage could not be ignored due to their unique extracellular persistence in environments. Overall, this is the first comprehensive survey about bacteriophage carried ARGs from farms in different regions in China.


Asunto(s)
Farmacorresistencia Bacteriana/genética , Heces/virología , Genes Bacterianos , Animales , Bacteriófagos/genética , Pollos , China , Granjas , Integrones , Plásmidos
13.
Chemosphere ; 240: 124851, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31546187

RESUMEN

Cadmium (Cd) is a toxic heavy metal and its uptake by living organisms causes adverse effect, further resulting in cycle pollution of the biosphere. The specific regulatory mechanism between clays and microbes under Cd stress remains unclear. In this study, interface interactions among clays, microbes and Cd were confirmed. Comparative transcriptome was conducted to investigate how it regulated gene expression patterns of microbes (Chryseobacterium sp. WAL2), which exposed to a series of gradient concentrations of Cd (16, 32, 64 and 128 µg mL-1) for 12 d in the presence and absence of clay montmorillonite (Mt) (16 g L-1). Cd was highly enriched by the unique interface interactions between Mt and bacteria (67.6-82.1%), leading to a more hostile environment for bacterial cells. However, Mt ultimately enhanced bacterial resistance to Cd stress by stimulating the mechanism of bacterial resistance; namely: (i) Mt increased genes expression connected with ion transport, enhancing the uptake of Cd; (ii) Mt stimulated genes expression related to efflux pump and positively regulated cellular oxidative stress (e.g., glutathione) and Cd accumulation (e.g., cysteine) processes. Further, genes expression related to intracellular metabolic processes was enforced, which supplied a driving force and accelerated electron transfer; (iii) Mt improved genes expression involved in DNA replication and other biological processes (e.g., terpenoid backbone biosynthesis) to maintain bacterial vitality. Therefore, the study not only optimized a unique Cd resistance mechanism of Mt on Chryseobacterium sp., but also provided a novel insight for environmental mitigation of heavy metals from the perspective of molecular biology.


Asunto(s)
Proteínas Bacterianas/genética , Bentonita/farmacología , Cadmio/toxicidad , Chryseobacterium/efectos de los fármacos , Chryseobacterium/fisiología , Farmacorresistencia Bacteriana/efectos de los fármacos , Proteínas Bacterianas/metabolismo , Cadmio/farmacocinética , Chryseobacterium/química , Farmacorresistencia Bacteriana/genética , Perfilación de la Expresión Génica , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Microbiología del Suelo , Espectroscopía Infrarroja por Transformada de Fourier , Difracción de Rayos X
14.
Eur J Med Chem ; 185: 111781, 2020 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-31654879

RESUMEN

We previously discovered a series of novel biaryloxazolidinone analogues bearing a hydrazone moiety with potent antibacterial activity. However, the most potent compound OB-104 exhibited undesirable chemical and metabolic instability. Herein, novel biaryloxazolidinone analogues were designed and synthesized to improve the chemical and metabolic stability. Compounds 6a-1, 6a-3, 14a-1, 14a-3 and 14a-7 showed significant antibacterial activity against the tested Gram-positive bacteria as compared to radezolid and linezolid. Further studies indicated that most of them exhibited improved water solubility and chemical stability. Compound 14a-7 had MIC values of 0.125-0.25 µg/mL against all tested Gram-positive bacteria, and showed excellent antibacterial activity against clinical isolates of antibiotic-susceptible and antibiotic-resistant bacteria. Moreover, it was stable in human liver microsome. From a safety viewpoint, it showed non-cytotoxic activity against hepatic cell and exhibited lower inhibitory activity against human MAO-A compared to linezolid. The potent antibacterial activity and all these improved drug-likeness properties and safety profile suggested that compound 14a-7 might be a promising drug candidate for further investigation.


Asunto(s)
Antibacterianos/farmacología , Farmacorresistencia Bacteriana/efectos de los fármacos , Bacterias Grampositivas/efectos de los fármacos , Inhibidores de la Monoaminooxidasa/farmacología , Oxindoles/farmacología , Antibacterianos/síntesis química , Antibacterianos/química , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Células Hep G2 , Humanos , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Monoaminooxidasa/metabolismo , Inhibidores de la Monoaminooxidasa/síntesis química , Inhibidores de la Monoaminooxidasa/química , Oxindoles/síntesis química , Oxindoles/química , Relación Estructura-Actividad
15.
Ann Otol Rhinol Laryngol ; 129(1): 5-11, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31390881

RESUMEN

OBJECTIVES: Intranasal septal splints are often used in nasal septal surgeries. Routine use of postoperative antibiotics is an accepted practice, although data regarding its efficacy in preventing postsurgical complications are limited. This study aimed to examine bacterial colonization on septal splints following prophylactic antibiotic therapy and the association with postoperative infections. METHODS: Fifty-five patients underwent septoplasty by a single surgeon between March 2015 and April 2016. All had intranasal septal splints and were given antibiotic prophylaxis for 7 days until removal of splints. Nasal cultures were taken before surgery, and septal splints were examined for bacterial colonization following their removal. RESULTS: Thirty-six patients (65%) had positive nasal culture prior to surgery. The most common isolates were Staphylococcus aureus (30%) and Enterobacteriaceae species (66%). All these patients had postoperative bacterial colonization on septal splints. In 15 patients with negative preoperative cultures, bacteria were isolated postoperatively. An increased resistance profile was documented postoperatively in 9 patients (16%), including two with multidrug resistance. In two of these patients preoperative wild-type strains acquired antibiotic resistance postoperatively. No adverse drug reactions to antibiotics were reported. CONCLUSIONS: Increased bacterial growth and emergence of resistant strains were observed on intranasal septal splints despite prophylactic antibiotic treatment. Nonetheless, this did not translate into clinical infection. Thus, considering antibiotics overuse and increasing bacterial resistance, further research is needed to determine the role of antibiotic prophylaxis in the setting of intranasal splints.


Asunto(s)
Antibacterianos/uso terapéutico , Profilaxis Antibiótica , Cavidad Nasal/microbiología , Tabique Nasal/cirugía , Procedimientos Quírurgicos Nasales/métodos , Férulas (Fijadores)/microbiología , Infección de la Herida Quirúrgica/prevención & control , Adolescente , Adulto , Anciano , Combinación Amoxicilina-Clavulanato de Potasio/uso terapéutico , Cefalexina/uso terapéutico , Técnicas de Cultivo , Farmacorresistencia Bacteriana , Farmacorresistencia Bacteriana Múltiple , Enterobacteriaceae/aislamiento & purificación , Infecciones por Enterobacteriaceae/epidemiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Infecciones Estafilocócicas/epidemiología , Staphylococcus aureus/aislamiento & purificación , Infección de la Herida Quirúrgica/epidemiología , Adulto Joven
16.
J Colloid Interface Sci ; 559: 313-323, 2020 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-31675662

RESUMEN

Antibiotic resistance is a common phenomenon observed during treatment with antibacterials. Use of nanozymes, especially those with synergistic enzyme-like activities, as antibacterials could overcome this problem, but their synthesis is limited by their high cost and/or complex production process. Herein, vanadium oxide nanodots (VOxNDs) were prepared via a one-step bottom-up ethanol-thermal method using vanadium trichloride as the precursor. VOxNDs alone possess bienzyme mimics of peroxidase and oxidase. Accordingly, highly efficient antibacterials against drug-resistant bacteria can be obtained through synergistic catalysis; the oxidase-like activity decomposes O2 to generate superoxide anion radical (O2-) and hydroxyl radicals (OH), and the intrinsic peroxidase-like activity can further induce the production of OH from external H2O2. Consequently, H2O2 concentration could decrease up to four magnitude orders with VOxNDs to achieve an antibacterial efficacy similar to that of H2O2 alone. Wound healing in vivo further confirms the high antibacterial efficiency, good biocompatibility, and application potential of the synergistic antibacterial system due to the "nano" structure of VOxNDs. The method of synthesis of nanodot antibacterials described in this paper is inexpensive, and the results of this study reveal the multi-enzymatic synergism of nanozymes.


Asunto(s)
Antibacterianos/química , Nanopartículas del Metal/química , Óxidos/química , Compuestos de Vanadio/química , Cicatrización de Heridas/efectos de los fármacos , Animales , Materiales Biocompatibles/química , Materiales Biomiméticos/química , Catálisis , Supervivencia Celular/efectos de los fármacos , Farmacorresistencia Bacteriana/efectos de los fármacos , Escherichia coli/efectos de los fármacos , Células HeLa , Células Endoteliales de la Vena Umbilical Humana , Humanos , Peróxido de Hidrógeno/química , Radical Hidroxilo/química , Peroxidasas/metabolismo , Ratas Sprague-Dawley , Staphylococcus aureus/efectos de los fármacos
17.
Huan Jing Ke Xue ; 41(1): 313-320, 2020 Jan 08.
Artículo en Chino | MEDLINE | ID: mdl-31854932

RESUMEN

Wastewater treatment plants hold a vast pool of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs). The aim of this study is to analyze the ARB and ARGs in a pharmaceutical and chemical wastewater treatment plant using a metagenomic technique. The results of taxonomic annotation revealed that bacteria were the predominant domain. The most abundant phyla and genus was Proteobacteria and Hyphomicrobium, respectively. A total of 74 categories of ARGs were predicted using CARD with the most dominant types being sav 1866, dfrE, and mfd. Furthermore, a network analysis was conducted to investigate the co-occurrence patterns between ARGs and microbial taxa. ARGs were found to be highly connected to microbial taxa at the genus level. With respect to the antibiotic resistance mechanisms, antibiotic-specific efflux pumps appeared to be the most common mechanisms. Among these, resistance-nodulation-cell division (RND) was the major type. The most important functional pathway of this microbial community was metabolic correlation. Interestingly, there were many genes related to human diseases, among which bacterial infectious diseases were the main ones. On the one hand, these data further confirmed that pharmaceutical and chemical wastewater treatment plants are rich in ARB and ARGs. The accumulation of ARGs increases the potential environmental risks, and hence it is necessary to strengthen the active monitoring of ARB and ARGs in pharmaceutical and chemical wastewater treatment plants. On the other hand, research on ARB and ARGs offers important information for the selection of deep processing technology to effectively remove ARB and ARGs.


Asunto(s)
Bacterias/clasificación , Farmacorresistencia Bacteriana , Genes Bacterianos , Aguas Residuales , Purificación del Agua , Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Humanos , Metagenoma , Preparaciones Farmacéuticas
18.
APMIS ; 128(1): 20-24, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31630449

RESUMEN

A case of bacteremia with the fastidious bacteria Actinomyces urogenitalis following lengthy urinary retention is reported in a sixty-year-old man. In 2013, the first case of bacteremia due to A. urogenitalis was presented, secondary to a tubo-ovarian abscess following transvaginal oocyte retrieval. To the best of our knowledge, this is the first male bacteremic episode involving A. urogenitalis related to a urinary tract focus. The patient had no prior urogenital medical history. Extensive susceptibility testing was done on isolates from urinary and blood cultures. The organism exhibited fluoroquinolone resistance but was susceptible to most other antibiotics used in the treatment of urinary infections. Due to its unusual growth requirements infections with A. urogenitalis are most likely an underdiagnosed entity.


Asunto(s)
Actinomicosis/diagnóstico , Bacteriemia/microbiología , Retención Urinaria/complicaciones , Infecciones Urinarias/microbiología , Actinomyces , Antibacterianos/uso terapéutico , Bacteriemia/tratamiento farmacológico , Farmacorresistencia Bacteriana , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Resultado del Tratamiento
19.
APMIS ; 128(1): 41-47, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31692136

RESUMEN

Campylobacteriosis is one of the most frequently reported zoonoses worldwide. The well-documented increase in the ciprofloxacin resistance has increased the importance of rapid detection of the resistance. The incidence of ciprofloxacin resistance was investigated using real-time PCR. Identification of one hundred and fifty-eight strains was performed by PCR. Minimum inhibitory concentration (MIC) of ciprofloxacin was determined by Epsilometer test. Following the confirmation of the efficiencies of singleplex real-time PCR methods using two different probes, a cytosine to thymine point mutation at codon 86 was detected by allelic discrimination. Of the 158 strains, 114 (72.2%) were determined to be resistant to ciprofloxacin. The MIC50 and the MIC90 of ciprofloxacin were found to be 8 and ≥32 mg/L, respectively. By real-time PCR, the presence of the mutation was confirmed in all, but one, resistant strains and the absence of the mutation was demonstrated in all, but one, susceptible strains. The rate of resistance is high among C. jejuni strains and ciprofloxacin should not be used in the treatment of such infections in Turkey. A cytosine to thymine mutation is the most frequently detected mechanism for the resistance. Real-time PCR can be used for the quick screening of the resistance.


Asunto(s)
Antibacterianos/farmacología , Campylobacter jejuni/efectos de los fármacos , Campylobacter jejuni/genética , Ciprofloxacino/farmacología , Farmacorresistencia Bacteriana/genética , Mutación Puntual , Alelos , Infecciones por Campylobacter/epidemiología , Infecciones por Campylobacter/microbiología , Pruebas Antimicrobianas de Difusión por Disco , Electroforesis en Gel de Campo Pulsado , Humanos , Concentración 50 Inhibidora , Pruebas de Sensibilidad Microbiana , Fenotipo , Prevalencia , Turquia
20.
APMIS ; 128(1): 48-60, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31693234

RESUMEN

Klebsiella pneumoniae is an important opportunistic pathogen with significant potential for virulence and multidrug resistance. Treatment failure often occurs because the pathogen may couple virulence and drug resistance with the stringent response. This study assessed the role of the spoT gene in environmental and nutritional stress tolerance, exopolysaccharide capsule production and biofilm formation. spoT mutants were constructed using the lambda red recombinase technique, and mutant and wild-type (WT) strains were exposed to limiting concentrations of carbon (glucose), phosphate and aminoacid, and environmental stresses of ethanol, salt and heat. Cell viability, capsule production and cell length were assessed as well as the ability to grow biofilm under antibiotic pressure using gentamicin and ceftazidime. spoT mutants were more susceptible to stresses versus WT; the reverse was true for survival during biofilm susceptibility assay (p < 0.05), especially when carbon and phosphate were present. spoT mutants were elongated and lacked a capsule versus WT and non-starved strains. The inability to produce capsule in mutants before and after starvation was likely a general effect of spoT mutation. These data suggest that the spoT-mediated stringent response is important for K. pneumoniae in conditions of nutrient limitation, environmental stress and antimicrobial pressure.


Asunto(s)
Antibacterianos/farmacología , Proteínas Bacterianas/genética , Biopelículas/crecimiento & desarrollo , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/fisiología , Estrés Fisiológico , Aminoácidos/química , Farmacorresistencia Bacteriana , Etanol/farmacología , Regulación Bacteriana de la Expresión Génica , Glucosa/química , Humanos , Klebsiella pneumoniae/efectos de los fármacos , Fosfatos/química , Cloruro de Sodio/farmacología , Virulencia/genética , Factores de Virulencia
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