Polymixin

Background: Colistin (polymyxin E) and polymixin B are important bactericidal antibiotics used in the treatment of serious infections caused by multi-drug resistant Gram-negative organisms. Transferrable plasmid-mediated colistin resistance, conferred by the product of the mcr - 1 gene, has emerged as a global healthcare threat. Consequently, the rapid detection of the MCR-1 protein in clinical bacterial isolates has become increasingly important. We used a genoproteomic approach to identify unique peptides of the MCR-1 protein that could be detected rapidly by liquid chromatography tandem mass spectrometry (LC-MS/MS)...

Population-based public health data on antibiotic resistance gene carriage is poorly surveyed. Research of the human microbiome as an antibiotic resistance reservoir has primarily focused on gut associated microbial communities, but data have shown more widespread microbial colonization across organs than originally believed, with organs previously considered as sterile being colonized. Our study demonstrates the utility of postmortem microbiome sampling during routine autopsy as a method to survey antibiotic resistance carriage in a general population...

The recent emergence of the plasmid-mediated colistin resistance gene mcr-1 poses a substantial clinical threat to the severe infections caused by CRE (Carbapenem Resistant Enterobacteriaceae), as the treatment failure of the mcr-1-positive CRE "Superbug" most likely occurs by using the combination of carbapenem and polymixins. Therefore, our study aims to seek a potent MCR-1 inhibitor to fight this infection. A checkerboard MIC (Minimum Inhibitory Concentration) assay, time-killing assay, MPNP (Modified rapid polymyxin Nordmann/Poirel) test, combined disk test and molecular modelling analysis were performed on different mcr-1-positive strains to confirm the synergistic effects of the combination of colistin and osthole (OST)...

Data on clinical applications of blood purification techniques in children are scarce. The aim of this review is to offer a clinical overview, as complete as possible, on blood purification in children with hyper-inflammatory syndromes (HS). A review of the literature using the PubMed, EMBASE, Web of Science, and Scopus databases, on the most recent data about blood purification in children was conducted until June 2018. Except for three randomized controlled trials (RCTs) on plasma exchange, no RCTs, but only observational studies or case reports were found regarding other blood purification techniques in children...

Vibrio cholerae is the causative agent of acute dehydrating diarrhoeal disease cholera. Among 71 V. cholerae non-O1/non-O139 isolates, all yielded negative results for ctxA , ctxB and tcpA genes in PCR assay. Few strains were positive for stn (28.38%), and ompU (31.08%) genes. While all isolates were negative for ace gene, only two were positive for zot gene. All strains expressed toxR and toxT genes. It was also found that all isolates were slime-producer and these were capable of forming moderate to high biofilm...

The Infiniplex for milk® (IPM) kit is a quick method for the simultaneous and qualitative detection of more than 100 molecules including antibiotic residues, mycotoxins, anti-inflammatories and antiparasitic drugs into a single test that does not require milk treatment. The IPM® kit was validated according to the European decision EC/2002/657 and according to the European guideline for the validation of screening methods (2010). Our validation was focused only on antibiotic residues. The washing step was identified as the most critical step of the assay...

Carbapenem-resistant Enterobacteriaceae (CRE) have evolved into a major challenge to antibiotic therapy worldwide. The problem is more confounding when wider dissemination of CRE occurs in the community and the environment. In this study, six blaNDM -harboring Enterobacteriaceae, four Klebsiella pneumoniae, and two Escherichia coli, isolated from seafood, were characterized with respect to their antibiotic resistance and the genetic factors responsible for these resistances. The isolates were resistant to all β-lactam antibiotics, quinolones, trimethoprim-sulfamethoxazole, chloramphenicol, and tetracycline and were susceptible to colistin, polymixin B, fosfomycin, and tigecycline...

Antibiotic discovery has experienced a severe slowdown in terms of discovery of new candidates. In vitro screening methods using phospholipids to model the bacterial membrane provide a route to identify molecules that specifically disrupt bacterial membranes causing cell death. Thanks to the electrically insulating properties of the major component of the cell membrane, phospholipids, electronic devices are highly suitable transducers of membrane disruption. The organic electrochemical transistor (OECT) is a highly sensitive ion-to-electron converter...

Mycoplasmas are intrinsically resistant to antimicrobials targeting the cell wall (fosfomycin, glycopeptides, or β-lactam antibiotics) and to sulfonamides, first-generation quinolones, trimethoprim, polymixins, and rifampicin. The antibiotics most frequently used to control mycoplasmal infections in animals are macrolides and tetracyclines. Lincosamides, fluoroquinolones, pleuromutilins, phenicols, and aminoglycosides can also be active. Standardization of methods used for determination of susceptibility levels is difficult since no quality control strains are available and because of species-specific growth requirements...

One of the most striking features of Pseudomonas aeruginosa is its outstanding capacity for developing antimicrobial resistance to nearly all available antipseudomonal agents through the selection of chromosomal mutations, leading to the failure of the treatment of severe hospital-acquired or chronic infections. Recent whole-genome sequencing (WGS) data obtained from in vitro assays on the evolution of antibiotic resistance, in vivo monitoring of antimicrobial resistance development, analysis of sequential cystic fibrosis isolates, and characterization of widespread epidemic high-risk clones have provided new insights into the evolutionary dynamics and mechanisms of P...

Carbapenem-resistance among enterobacteriaceae has become a global health concern. The objective of this study was to understand NDM producing enterobacteriaceae and their genetic basis of resistance, spreading in neonatal intensive care unit. Carbapenem resistant NDM producing enterobacteriaceae isolates were recovered from rectal swab and blood sample of infants admitted in NICU. These were determined by using Carba-NP test. All isolates were identified using BD PhoenixTM-100 and MICs were determined by broth microdilution method...

The emergence of multiple drug-resistant (MDR) Acinetobacter baumannii strains has become a global problem. This study aimed to evaluate the occurrence of antibiotic resistance and to investigate the presence of antibiotic resistance determinants among A. baumannii isolates obtained from hospitalized patients in Iran. This cross-sectional study was performed on 92 A. baumannii isolates in the years 2015-2016. Antimicrobial susceptibility testing was carried out by the disk diffusion method. The presence of antibiotic resistance determinants was detected by the PCR method...

Strain ZX02 was isolated from Chinese ginger cultivated soil contaminated with various pesticides, which could utilize 2,4-dichlorophenoxyacetic acid butyl ester (2,4-D butyl ester) as the sole carbon source. On the basis of the sequence analysis of 16S rRNA gene as well as the morphological, biochemical, and physiological characteristics of strain ZX02, the organism belonged to Gram-negative bacterium and was identified as Acinetobacter sp. ZX02. The strain ZX02 showed a remarkable performance in 2,4-D butyl ester degradation (100% removal in <96 h) in pure culture...

Colistin sulfate (polymixin E) is an antibiotic prescribed with increasing frequency for severe Gram-negative bacterial infections. As nephrotoxicity is a common side effect, the discovery of pharmacogenomic markers associated with toxicity would benefit the utility of this drug. Our objective was to identify genetic markers of colistin cytotoxicity that were also associated with expression of key proteins using an unbiased, whole genome approach and further evaluate the functional significance in renal cell lines...

Fourteen endophytic bacterial isolates were isolated from the rhizome of Curcuma longa L. were characterized on the basis of morphology, biochemical characteristics and 16S rRNA gene sequence analysis. The isolates were identified to six strains namely Bacillus cereus (ECL1), Bacillus thuringiensis (ECL2), Bacillus sp. (ECL3), Bacillus pumilis (ECL4), Pseudomonas putida (ECL5), and Clavibacter michiganensis (ECL6). All the strains produced IAA and solubilized phosphate and only two strains produced siderophore (ECL3 and ECL5) during plant growth promoting trait analysis...

BACKGROUND: Probiotic yeast has become a field of interest to scientists in recent years. METHODS: Conventional cultural method was employed to isolate and identify yeast and standard methods were used to determine different probiotic attributes, antimicrobial and antioxidant properties. RESULTS: This study reports potential probiotic properties of a strain of S. cerevisiae IFST 062013 isolated from fruit. The isolate is tolerant to a wide range of temperature and pH, high concentration of bile salt and NaCl, gastric juice, intestinal environment, α-amylase, trypsin and lysozyme...

The polymixin colistin is a "last line" antibiotic against extensively-resistant Gram-negative bacteria. Recently, the mcr-1 gene was identified as a plasmid-mediated resistance mechanism in human and animal Enterobacteriaceae, with a wide geographical distribution and many producer strains resistant to multiple other antibiotics. mcr-1 encodes a membrane-bound enzyme catalysing phosphoethanolamine transfer onto bacterial lipid A. Here we present crystal structures revealing the MCR-1 periplasmic, catalytic domain to be a zinc metalloprotein with an alkaline phosphatase/sulphatase fold containing three disulphide bonds...

BACKGROUND: Bacteria that produce Klebsiella pneumoniae carbapenemases (KPCs) are resistant to broad-spectrum β-lactam antibiotics. The objective of this study was to phenotypically and genotypically characterize the antibiotic susceptibility to carbapenems of 297 isolates recovered from clinical samples obtained from inpatients at 16 hospitals in São Luis (Maranhão, Brazil). METHODS: The study was conducted using phenotypic tests and molecular methods, including polymerase chain reaction (PCR), sequencing and enterobacterial repetitive intergenic consensus (ERIC)-PCR...

Klebsiella pneumoniae carbapenemases (KPCs) are plasmid encoded carbapenem hydrolyzing enzymes which have the potential to spread widely through gene transfer. The instability of upstream region of blaKPC accelerates emergence of different isoforms. Routine antibiotic susceptibility testing failed to detect KPC producers and some commercial kits have been launched for early identification of KPC producers. Notable among the drugs under development against KPC are mostly derivatives of polymixin; ß-lactamase inhibitor NXL104 with combination of oxyimino cephalosporin as well as with ceftazidime; a novel tricyclic carbapenem, LK-157, potentially useful against class A and class C enzymes; BLI-489-a bicyclic penem derivative; PTK-0796, a tetracycline derivative and ACHN-490...

BACKGROUND: Indiscriminate use of antibiotics in urinary tract infections have led to emergence of 'superbugs' worldwide. Periodical review of antibiograms is of utmost importance for optimum patient benefit. OBJECTIVE: To identify the spectrum of organisms responsible for urinary tract infection and evaluate the pattern of antibiotic sensitivity of the organisms. METHODS: Urine samples were collected from all consecutive patients getting admitted in the medicine indoor irrespective of symptomatology...