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Polymyxin resistance

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https://www.readbyqxmd.com/read/29045123/polymyxin-b3-tobramycin-hybrids-with-pseudomonas-aeruginosa-selective-antibacterial-activity-and-strong-potentiation-of-rifampicin-minocycline-and-vancomycin
#1
Ronald Domalaon, Xuan Yang, Yinfeng Lyu, George G Zhanel, Frank M Schweizer
There is an urgent need to develop novel antibacterial agents able to eradicate drug-resistant Gram-negative pathogens such as Pseudomonas aeruginosa. Antimicrobial hybrids have emerged as a promising strategy to combat bacterial resistance, as a stand-alone drug but also as an adjuvant in combination with existing antibiotics. Herein, we report for the first time the synthesis and biological evaluation of polymyxin-aminoglycoside heterodimers composing of polymyxin B3 covalently linked to tobramycin via an aliphatic hydrocarbon linker...
October 18, 2017: ACS Infectious Diseases
https://www.readbyqxmd.com/read/29038262/severe-infusion-related-adverse-events-and-renal-failure-in-patients-receiving-high-dose-intravenous-polymyxin-b
#2
Josiane F John, Diego R Falci, Maria Helena Rigatto, Renata D Oliveira, Thaysa G Kremer, Alexandre P Zavascki
Very high doses of polymyxin B (PMB) have been addressed in in vitro experiments against carbapenem-resistant Gram-negative bacilli as a strategy to improve bacterial killing and suppress resistance emergence. However, the toxicities of very high doses in patients are unknown. This is a retrospective cohort study assessing patients receiving >3mg/kg/day or a total dose ≥250mg/day of PMB. The main outcomes were severe infusion-related adverse event according to Common Terminology Criteria for Adverse Criteria and renal failure category of RIFLE criteria for acute kidney injury (AKI) during treatment...
October 16, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/29030025/emerge-of-blandm-1-and-blaoxa-48-like-harboring-carbapenem-resistant-klebsiella-pneumoniae-isolates-from-hospitalized-patients-in-southwestern-iran
#3
Zahra Hosseinzadeh, Hadi Sedigh Ebrahim-Saraie, Jamal Sarvari, Jalal Mardaneh, Behzad Dehghani, Seyed Mohammad Hossein Rokni-Hosseini, Mohammad Motamedifar
BACKGROUND: One of the most important emerging carbapenem-resistant bacteria is Klebsiella pneumoniae (K. pneumoniae). The present study aimed to investigate the antibiotic susceptibility pattern of K. pneumoniae isolates and detection of carbapenemase producing K. pneumoniae obtained from Iranian hospitalized patients. METHODS: This cross-sectional study was performed on 211 K. pneumoniae isolates which were recovered from different clinical specimens from 2014 to 2015...
October 10, 2017: Journal of the Chinese Medical Association: JCMA
https://www.readbyqxmd.com/read/29028568/virulence-genotypes-and-antimicrobial-susceptibility-patterns-of-arcobacter-butzleri-isolated-from-seafood-and-its-environment
#4
Srinu Rathlavath, Vandita Kohli, Asem Sanjit Singh, Manjusha Lekshmi, Gayatri Tripathi, Sanath Kumar, Binaya Bhusan Nayak
Arcobacter butzleri is an emerging pathogen isolated from animals, food and the environment. In this study, 147 A. butzleri isolated from seafood and the coastal environment were tested for the presence of ten putative virulence genes (cadF, cj1349, ciaB, mviN, pldA, tlyA, hecA, hecB, irgA, iroE) and antimicrobial susceptibilities. Majority of the isolates harbored mviN (100%), cj1349 (97.2%), ciaB (95.9%), tlyA (91.8%), pldA (91.1%) and cadF (89.7%). Lower detection rates were observed for hecA (10.8%), hecB (19%), iroE (12...
October 3, 2017: International Journal of Food Microbiology
https://www.readbyqxmd.com/read/29026662/intrathecal-and-intraventricular-antibiotics-for-postoperative-gram-negative-meningitis-and-ventriculitis
#5
Saad Akhtar Khan, Muhammad Waqas, Usman T Siddiqui, Muhammad Shahzad Shamim, Karim Rizwan Nathani, Rashid Jooma, Faisal Mehmood
BACKGROUND: Postoperative meningitis is a growing cause of concern, especially with the evolution of multidrug-resistant organism. The authors evaluate the use of intraventricular/intrathecal (IVT/IT) antibiotics for postoperative gram-negative meningitis in patients whom intravenous antibiotics were ineffective. METHODS: Medical records were retrospectively reviewed and neurosurgery patients with gram-negative postoperative infection meningitis/ventriculitis were enrolled in the study...
2017: Surgical Neurology International
https://www.readbyqxmd.com/read/29026355/colistin-and-polymyxin-b-minimal-inhibitory-concentrations-determined-by-etest-found-unreliable-for-gram-negative-bacilli
#6
Shelby Simar, Diane Sibley, Deborah Ashcraft, George Pankey
BACKGROUND: A reliable method of polymyxin B and E (colistin) susceptibility testing remains elusive. These drugs diffuse poorly into agar, creating potentially inaccurate Etest and disk diffusion results, and testing by these methods is not recommended. Broth microdilution is the reference testing method, although it can be sometimes difficult to interpret. Currently, when a colistin susceptibility test is ordered for a patient in the Ochsner Health System, our diagnostic microbiology laboratory performs the Etest...
2017: Ochsner Journal
https://www.readbyqxmd.com/read/29019016/repurposing-zidovudine-in-combination-with-tigecycline-for-treating-carbapenem-resistant-enterobacteriaceae-infections
#7
S M S Ng, J S P Sioson, J M Yap, F M Ng, H S V Ching, J W P Teo, R Jureen, J Hill, C S B Chia
The global emergence of carbapenem-resistant Enterobacteriaceae (CRE) presents a significant clinical concern, prompting the WHO to prioritize CRE as a top priority pathogen in their 2017 global antibiotic-resistant bacteria priority list. Due to the fast-depleting antibiotic arsenal, clinicians are now resorting to using once-abandoned, highly toxic antibiotics such as the polymyxins and aminoglycosides, creating an urgent need for new antibiotics. Drug repurposing, the application of an approved drug for a new therapeutic indication, is deemed a plausible solution to this problem...
October 10, 2017: European Journal of Clinical Microbiology & Infectious Diseases
https://www.readbyqxmd.com/read/28984232/chromagar-col-apse-a-selective-bacterial-culture-medium-for-the-isolation-and-differentiation-of-colistin-resistant-gram-negative-pathogens
#8
Muhd Haziq F Abdul Momin, David C Bean, Rene S Hendriksen, Marisa Haenni, Lynette M Phee, David W Wareham
PURPOSE: A selective chromogenic culture medium for the laboratory isolation and differentiation of colistin resistant Acinetobacter, Pseudomonas, Stenotrophomonas and Enterobacteriaceae spp. (CHROMagar COL-APSE) was developed, evaluated and compared to an existing selective bacterial culture medium (SuperPolymyxin). METHODOLOGY: The medium was challenged with 84 isolates, including polymyxin B (POL B)-susceptible and -resistant type strains and colistin (COL)-resistant organisms recovered from human and animal samples...
October 6, 2017: Journal of Medical Microbiology
https://www.readbyqxmd.com/read/28978685/detection-of-colistin-resistant-mcr-1-positive-escherichia-coli-using-inhibition-by-edta-and-zeta-potential-assays
#9
Fernanda Esposito, Miriam R Fernandes, Ralf Lopes, Maria Muñoz, Caetano P Sabino, Marcos P Cunha, Ketrin C Silva, Rodrigo Cayô, Willames M Martins, Andrea M Moreno, Terezinha Knöbl, Ana C Gales, Nilton Lincopan
The emergence and rapid dissemination of colistin-resistant Escherichia coli carrying the plasmid-mediated mcr-1 gene has created an urgent need to develop specific screening methods. In this study, we evaluate four assays based on the inhibition of the MCR-1 activity by EDTA: i) a combined disk test (CDT) comparing the inhibition zones of colistin (10 μg) and colistin-plus-EDTA (10 μg-plus-100 mM); ii) reduction of colistin MIC (CMR) in the presence of EDTA (80 μg/mL); iii) a modified rapid polymyxin Nordmann/Poirel test (MPNP) and; iv) alteration of Zeta potential (RZP= ZP+EDTA/ZP-EDTA)...
October 4, 2017: Journal of Clinical Microbiology
https://www.readbyqxmd.com/read/28976035/probing-the-srna-regulatory-landscape-of-p-aeruginosa-post-transcriptional-control-of-determinants-of-pathogenicity-and-antibiotic-susceptibility
#10
Yi-Fan Zhang, Kook Han, Courtney E Chandler, Brian Tjaden, Robert K Ernst, Stephen Lory
During environmental adaptation bacteria use small regulatory RNAs (sRNAs) to repress or activate expression of a large fraction of their proteome. We extended the use of the in vivo RNA proximity ligation method towards probing global sRNA interactions with their targets in Pseudomonas aeruginosa and verified the method with a known regulon controlled by the PrrF1 sRNA. We also identified two sRNAs (Sr0161 and ErsA) that interact with the mRNA encoding the major porin OprD responsible for the uptake of carbapenem antibiotics...
October 4, 2017: Molecular Microbiology
https://www.readbyqxmd.com/read/28962863/polymyxin-susceptibility-testing-interpretative-breakpoints-and-resistance-mechanism-an-update
#11
REVIEW
Yamuna Devi Bakthavatchalam, Agila Kumari Pragasam, Indranil Biswas, Balaji Veeraraghavan
Emerging multi-drug resistant (MDR) nosocomial pathogens is a great threat. Polymyxin, an old cationic polypeptide, is considered as the last resort drug in treating infections associated with MDR Gram-negative bacteria. Increased use of polymyxins in treating critical patient necessitates, routine testing of polymyxins. However, susceptibility testing of both colistin and polymyxin B are challenging. Currently, available susceptibility testing methods are briefly discussed in this review. The multicomponent composition of colistin and polymyxin B influences significantly the susceptibility testing...
September 26, 2017: Journal of Global Antimicrobial Resistance
https://www.readbyqxmd.com/read/28961485/the-development-and-validation-of-a-simple-liquid-chromatography-tandem-mass-spectrometry-method-for-polymyxin-b1-and-b2-quantification-in-different-matrices
#12
Jenna Covelli, Donna Ruszaj, Robert Straubinger, Jian Li, Gauri G Rao
Polymyxin B has resurfaced as a last-line treatment for multi-drug resistant Gram-negative bacteria. Accurate characterization and quantification of polymyxin B components is necessary to optimize this therapy. We developed and validated a robust, straightforward LC-MS/MS method to quantify polymyxin B1 and B2, the primary polymyxin B components, in various matrices (cation-adjusted Mueller-Hinton broth (CAMHB), human and rat plasma). Of sample preparation approaches investigated, two protein precipitation/extraction methods were developed as part of an analytical strategy based upon reverse-phase LC-MS/MS using electrospray ionization in positive multiple-reaction monitoring mode...
September 21, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/28958847/small-molecule-adjuvants-that-suppress-both-chromosomal-and-mcr-1-encoded-colistin-resistance-and-amplify-colistin-efficacy-in-polymyxin-susceptible-bacteria
#13
William T Barker, Sara E Martin, Courtney E Chandler, T Vu Nguyen, Tyler L Harris, Christopher Goodell, Roberta J Melander, Yohei Doi, Robert K Ernst, Christian Melander
Bacterial resistance to polymyxin antibiotics has taken on a new and more menacing form. Common are genomically-encoded resistance mechanisms to polymyxins, specifically colistin (polymyxin E), however, the plasmid-borne mobile colistin resistance-1 (mcr-1) gene has recently been identified and poses a new threat to global public health. Within six months of initial identification in Chinese swine in November 2015, the first human clinical isolation in the US was reported (Apr. 2016). Herein we report successful reversion of mcr-1-driven colistin resistance in Acinetobacter baumannii, Klebsiella pneumoniae, and Escherichia coli with adjuvants we previously reported as modulators of chromosomally-encoded colistin resistance...
October 15, 2017: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/28954688/a-manganese-photosensitive-tricarbonyl-molecule-mn-co-3-tpa-%C3%AE%C2%BA-3-n-br-enhances-antibiotic-efficacy-in-a-multi-drug-resistant-escherichia-coli
#14
Namrata Rana, Helen E Jesse, Mariana Tinajero-Trejo, Jonathan A Butler, John D Tarlit, Milena L von Und Zur Muhlen, Christoph Nagel, Ulrich Schatzschneider, Robert K Poole
Carbon monoxide-releasing molecules (CORMs) are a promising class of new antimicrobials, with multiple modes of action that are distinct from those of standard antibiotics. The relentless increase in antimicrobial resistance, exacerbated by a lack of new antibiotics, necessitates a better understanding of how such novel agents act and might be used synergistically with established antibiotics. This work aimed to understand the mechanism(s) underlying synergy between a manganese-based photoactivated carbon monoxide-releasing molecule (PhotoCORM), [Mn(CO)3(tpa-κ(3)N)]Br [tpa=tris(2-pyridylmethyl)amine], and various classes of antibiotics in their activities towards Escherichia coli EC958, a multi-drug-resistant uropathogen...
September 28, 2017: Microbiology
https://www.readbyqxmd.com/read/28941393/mobile-health-application-to-assist-doctors-in-antibiotic-prescription-an-approach-for-antibiotic-stewardship
#15
Felipe Francisco Tuon, Juliano Gasparetto, Luciana Cristina Wollmann, Thyago Proença de Moraes
BACKGROUND: Technologies applied to mobile devices can be an important strategy in antibiotic stewardship programs. OBJECTIVE: The aim of this study was to determine the impact of a decision-making application on antibiotic prescription. METHODS: This was an observational, analytical and longitudinal study on the implementation of an antimicrobial guide for mobile application (app). This study analyzed the period of 12 months before and 12 months after the app implementation at a university hospital based on local epidemiology, avoiding high cost drugs and reducing the potential for drug resistance including carbapenem...
September 20, 2017: Brazilian Journal of Infectious Diseases
https://www.readbyqxmd.com/read/28929967/-results-of-a-multicenter-study-investigating-plasmid-mediated-colistin-resistance-genes-mcr-1-and-mcr-2-in-clinical-enterobacteriaceae-%C3%A4-solates-from-turkey
#16
Ayşe Nur Sarı, Serap Süzük, Onur Karatuna, Dilara Öğünç, Ayşe Esra Karakoç, Zeynep Çizmeci, Hikmet Eda Alışkan, Füsun Cömert, Mustafa Zahir Bakıcı, Nezahat Akpolat, Fatma Feriha Çilli, Yasemin Zer, Aysel Karataş, Bahar Akgün Karapınar, Gülçin Bayramoğlu, Melda Özdamar, Fatma Kalem, Nuran Delialioğlu, Elif Aktaş, Nisel Yılmaz, Şaban Gürcan, Zeynep Gülay
Colistin is a polymyxin antibiotic which is considered as one of the last line agents against infections due to multidrug resistant or carbapenem resistant gram-negative pathogens. Colistin resistance is associated with chromosomal alterations which can usually cause mutations in genes coding specific two component regulator systems. The first plasmid-mediated colistin resistance gene, mcr-1 was described in Escherichia coli and Klebsiella pneumoniae isolates in December 2015 and followed by another plasmid-mediated colistin resistance gene mcr-2 in 2016...
July 2017: Mikrobiyoloji Bülteni
https://www.readbyqxmd.com/read/28915357/a-i-yigp-i-mutant-strain-is-a-small-colony-variant-of-i-e-coli-i-and-shows-pleiotropic-antibiotic-resistance
#17
Hui Xia, Qiongwei Tang, Jie Song, Jiang Ye, Haizhen Wu, Huizhan Zhang
Small colony variants (SCVs) are a commonly observed subpopulation of bacteria that have a small colony size and distinctive biochemical characteristics. SCVs are more resistant to some antibiotics than the wild-type, and usually cause persistent infections in the clinic. SCV studies have been very active during the past two decades, especially of <i>Staphylococcus aureus</i>. However, fewer studies on <i>Escherichia coli </i>SCVs exist, so we studied an <i>E. coli </i>SCV during an experiment involving the deletion of the<i> yigP</i> locus...
September 15, 2017: Canadian Journal of Microbiology
https://www.readbyqxmd.com/read/28910166/prevalence-antimicrobial-resistance-and-relatedness-of-salmonella-isolated-from-chickens-and-pigs-on-farms-abattoirs-and-markets-in-sichuan-province-china
#18
Suzhen Ma, Changwei Lei, Linghan Kong, Wei Jiang, Bihui Liu, Shuai Men, Yanxian Yang, Guangyang Cheng, Yanpeng Chen, Hongning Wang
This study aims at investigating the distribution, antimicrobial resistance, and genetic relationship of Salmonella isolated from 18 farms, their downstream abattoirs, and markets of chickens and pigs in Sichuan province, China. A total of 193 Salmonella isolates were identified from 693 samples with an isolation rate of 26.27% (88/335) in chickens and 29.33% (105/358) in pigs. Salmonella was isolated more frequently in abattoirs and markets than from farms. Serotypes were determined according to the White-Kauffmann-Le Minor scheme and 16 different serotypes were identified, with Derby being the most common, followed by Typhimurium and Meleagridis...
September 14, 2017: Foodborne Pathogens and Disease
https://www.readbyqxmd.com/read/28906060/novel-coordination-of-lipopolysaccharide-modifications-in-vibrio-cholerae-promotes-camp-resistance
#19
Carmen M Herrera, Jeremy C Henderson, Alexander A Crofts, M Stephen Trent
In the environment and during infection, the human intestinal pathogen Vibrio cholerae must overcome noxious compounds that damage the bacterial outer membrane. The El Tor and classical biotypes of O1 V. cholerae show striking differences in their resistance to membrane disrupting cationic antimicrobial peptides (CAMPs), such as polymyxins. The classical biotype is susceptible to CAMPs, but current pandemic El Tor biotype isolates gain CAMP resistance by altering the net charge of their cell surface through glycine modification of lipid A...
September 14, 2017: Molecular Microbiology
https://www.readbyqxmd.com/read/28904326/intravenous-polymyxins-revival-with-puzzle
#20
Yun Yu, Aihua Fei, Zengbin Wu, Chengjin Gao, Shuming Pan
With the increasing incidence of multi-drug resistant strains, especially carbapenem resistant strains, polymyxsins (mainly colistin and polymyxin B) based regimens seem to be a revival as an effective treatment of last resort in these infections. Evidence from 47 clinical trials or case series we reviewed showed that polymyxins based regimens are effective and have less toxicity compared with previous trials. When used alone, the mortality of intravenous polymyxsins ranged from 0% to 74.3%, clinical response (cure and improvement) rate was 7-82...
2017: Bioscience Trends
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