scholarly journals Quantitative Insights Into β-Lactamase Inhibitor’s Contribution in the Treatment of Carbapenemase-Producing Organisms With β-Lactams

2021 ◽  
Vol 12 ◽  
Author(s):  
Yanfang Feng ◽  
Arend L. de Vos ◽  
Shakir Khan ◽  
Mary St. John ◽  
Tayyaba Hasan
Keyword(s):  
Infectious Disease ◽  
Molecular Diagnostics ◽  
Susceptibility Testing ◽  
Quantitative Relationship ◽  
Mortality Rates ◽  
Resistance Mechanisms ◽  
Antibiotic Susceptibility Testing ◽  
Molecular Identity ◽  
Infection Treatment ◽  
High Degree

Objectives: Carbapenemase-producing organisms (CPOs) are associated with high mortality rates. The recent development of β-lactamase inhibitors (BLIs) has made it possible to control CPO infections safely and effectively with β-lactams (BLs). This study aims to explicate the quantitative relationship between BLI’s β-lactamase inhibition and CPO’s BL susceptibility restoration, thereby providing the infectious disease society practical scientific grounds for regulating the use of BL/BLI in CPO infection treatment.Methods: A diverse collection of human CPO infection isolates was challenged by three structurally representative BLIs available in the clinic. The resultant β-lactamase inhibition, BL susceptibility restoration, and their correlation were followed quantitatively for each isolate by coupling FIBA (fluorescence identification of β-lactamase activity) and BL antibiotic susceptibility testing.Results: The β-lactamase inhibition and BL susceptibility restoration are positively correlated among CPOs under the treatment of BLIs. Both of them are dependent on the target CPO’s carbapenemase molecular identity. Of note, without sufficient β-lactamase inhibition, CPO’s BL susceptibility restoration is universally low across all tested carbapenemase molecular groups. However, a high degree of β-lactamase inhibition would not necessarily lead to a substantial BL susceptibility restoration in CPO probably due to the existence of non-β-lactamase BL resistance mechanisms.Conclusion: BL/BLI choice and dosing should be guided by quantitative tools that can evaluate the inhibition across the entire β-lactamase background of the CPO upon the BLI administion. Furthermore, rapid molecular diagnostics for BL/BLI resistances, especially those sensitive to β-lactamase independent BL resistance mechanisms, should be exploited to prevent ineffective BL/BLI treatment.

Comparative analysis ofShigella sonneibiotype g isolated from paediatric populations in Egypt, 1999–2005

2012 ◽  
Vol 141 (8) ◽  
pp. 1614-1624 ◽  
Author(s):  
J. DEJLI ◽  
R. A. NADA ◽  
A. MANSOUR ◽  
A. A. EL-MONIEM ◽  
M. O. WASFY ◽  
...  
Keyword(s):  
Gel Electrophoresis ◽  
Genetic Similarity ◽  
Susceptibility Testing ◽  
Biochemical Characterization ◽  
Multidrug Resistant ◽  
Pulsed Field Gel Electrophoresis ◽  
Antibiotic Susceptibility Testing ◽  
Severe Diarrhoea ◽  
Plasmid Profiling ◽  
High Degree

SUMMARYStrain characteristics of 51Shigella sonneiisolates obtained from children seeking medical care (MC) and 48 isolates recovered during a prospective diarrhoea birth cohort (BC) study were compared. Biochemical characterization and antibiotic susceptibility testing determined that allS. sonneiisolates were biotype g and multidrug-resistant. Plasmid profiling identified 15 closely related patterns andXbaI pulsed-field gel electrophoresis confirmed the high degree of genetic similarity between isolates. AllS.sonneiisolates harbouredipaHand class II integrase genes and 84·3 and 80% of the MC and BC isolates, respectively carried thesengene. Neither the class I integrase nor thesetgene was detected. Our results indicate thatS. sonneiisolates associated with severe diarrhoea were indistinguishable from those associated with mild diarrhoea. Additional genetic tests with greater discrimination might offer an opportunity to determine genetic differences within the globally disseminating biotype g clone.

scholarly journals Environmental and Pathogenic Carbapenem Resistant Bacteria Isolated from a Wastewater Treatment Plant Harbour Distinct Antibiotic Resistance Mechanisms

Antibiotics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1118
Author(s):  
Micaela Oliveira ◽  
Inês Carvalho Leonardo ◽  
Mónica Nunes ◽  
Ana Filipa Silva ◽  
Maria Teresa Barreto Crespo
Keyword(s):  
Antibiotic Resistance ◽  
Wastewater Treatment ◽  
Susceptibility Testing ◽  
Treatment Plant ◽  
Antibiotic Resistance Genes ◽  
Resistance Mechanisms ◽  
Resistant Bacteria ◽  
Antibiotic Susceptibility Testing ◽  
Carbapenem Resistant ◽  
Acquired Antibiotic Resistance

Wastewater treatment plants are important reservoirs and sources for the dissemination of antibiotic resistance into the environment. Here, two different groups of carbapenem resistant bacteria—the potentially environmental and the potentially pathogenic—were isolated from both the wastewater influent and discharged effluent of a full-scale wastewater treatment plant and characterized by whole genome sequencing and antibiotic susceptibility testing. Among the potentially environmental isolates, there was no detection of any acquired antibiotic resistance genes, which supports the idea that their resistance mechanisms are mainly intrinsic. On the contrary, the potentially pathogenic isolates presented a broad diversity of acquired antibiotic resistance genes towards different antibiotic classes, especially β-lactams, aminoglycosides, and fluoroquinolones. All these bacteria showed multiple β-lactamase-encoding genes, some with carbapenemase activity, such as the blaKPC-type genes found in the Enterobacteriaceae isolates. The antibiotic susceptibility testing assays performed on these isolates also revealed that all had a multi-resistance phenotype, which indicates that the acquired resistance is their major antibiotic resistance mechanism. In conclusion, the two bacterial groups have distinct resistance mechanisms, which suggest that the antibiotic resistance in the environment can be a more complex problematic than that generally assumed.

scholarly journals Rapid Phenotypic Antibiotic Susceptibility Testing Through RNA Detection

2017 ◽  
Vol 4 (suppl_1) ◽  
pp. S33-S33 ◽  
Author(s):  
Roby Bhattacharyya ◽  
Jamin Liu ◽  
Peijun Ma ◽  
Nirmalya Bandyopadhyay ◽  
Jonathan Livny ◽  
...  
Keyword(s):  
Antibiotic Susceptibility ◽  
Susceptibility Testing ◽  
Genetic Resistance ◽  
Resistance Mechanisms ◽  
Resistant Isolate ◽  
Antibiotic Susceptibility Testing ◽  
Acinetobacter Baumanii ◽  
Rna Detection ◽  
Culture Bottle ◽  
Phenotypic Assay

Abstract Background Culture-based antibiotic susceptibility testing, the gold standard, is too slow to guide early antibiotic selection, while newer genotypic methods require comprehensive knowledge of resistance mechanisms to predict phenotype. Quantitative measurement of key antibiotic-responsive transcripts offers a rapid, phenotypic assay for assessing antibiotic susceptibility, agnostic to the genetic basis for resistance. Methods We performed RNA-Seq on Klebsiella pneumoniae and Acinetobacter baumanii treated with ciprofloxacin, gentamicin, or meropenem for 0, 10, 30, and 60 minutes. For each, we identified 50 responsive transcripts whose expression levels differ most between susceptible and resistant organisms upon antibiotic exposure. We measured their expression using a multiplexed fluorescent RNA hybridization assay (NanoString) in 69 clinical isolates, including a “test set” of multidrug-resistant strains from the CDC, in an 8-hour assay. Gene expression data from test strains were compared against known susceptible and resistant isolates to generate a transcriptional susceptibility metric. We also designed NanoString probes to detect 5 carbapenemase genes (KPC-2, KPC-3, NDM-1, OXA-48, and CTX-M15). Results Across all bacteria-antibiotic pairs tested, a susceptibility metric derived from these transcriptional assays correctly grouped isolates in 167 of 173 tests (Table 1), with only 1 of 88 resistant isolates misclassified as susceptible. Five of six incorrectly grouped isolates were within one dilution of the breakpoint MIC, including the misclassified resistant isolate. Conclusion We demonstrate phenotypic antibiotic resistance detection based on fluorescent RNA detection in an 8-hour assay. We have previously published proof-of-concept studies that this assay may be run on a positive blood culture bottle with minimal sample processing. By coupling this phenotypic assay with detection of genetic resistance determinants (demonstrated for carbapenemases) in a single assay, strains with unexplained resistance can be prioritized for further study. Disclosures All authors: No reported disclosures.

scholarly journals Phenotypic characterization and colistin susceptibilities of carbapenem-resistant of Pseudomonas aeruginosa and Acinetobacter spp.

2013 ◽  
Vol 7 (11) ◽  
pp. 880-887 ◽  
Author(s):  
Srujana Mohanty ◽  
Vijeta Maurya ◽  
Rajni Gaind ◽  
Monorama Deb
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Susceptibility Testing ◽  
Carbapenem Resistance ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Phenotypic Characterization ◽  
Antibiotic Susceptibility Testing ◽  
Colistin Resistance ◽  
Carbapenem Resistant ◽  
Acinetobacter Spp

Introduction: Pseudomonas aeruginosa and Acinetobcter spp. are important nosocomial pathogens and carbapenem resistance is an emerging threat. Therapeutic  options for infections with these isolates include colistin. This study was conducted to determine the prevalence of carbapenem resistance in P. aeruginosa and Acinetobacter spp. bloodstream isolates, phenotypically characterize the resistance mechanisms and evaluate the invitro activity of colistin. Methodology: Consecutive 145 (95 P.aeruginosa and 50 Acinetobacter spp.) non-repeat isolates were included. Antibiotic susceptibility testing was performed per CLSI guidelines. MIC for carbapenems and colistin was performed using Etest. Isolates showing reduced susceptibility or resistance to the carbapenems were tested for metallo-β-lactamase (MBL) production using imipenem-EDTA combined disk and MBL Etest. Results: Carbapenem resistance was observed in 40% P. aeruginosa and 66.0% Acinetobacter spp. Carbapenem-resistant (CA-R) isolates were significantly (p< 0.05) more frequently resistant to the other antibiotics than carbapenem-susceptible isolates. Approximately half of the CA-R strains were multidrug-resistant, and 3.1-5.5% were resistant to all antibiotics tested. MBL was found in 76.3% and 69.7% of the P. aeruginosa and Acinetobacter spp., respectively. Colistin resistance was observed in three (6.0%) Acinetobacter isolates and eight (8.4%)  P. aeruginosa. MIC50 for carbapenems were two to four times higher for MBL-positive compared to MBL-negative isolates, but no difference was seen in MIC for colistin. Conclusion: Carbapenem resistance was observed to be mediated by MBL in a considerable number of isolates.  Colistin is an alternative for infections caused by CA-R isolates; however, MIC testing should be performed whenever clinical use of colistin is considered.

Tissue section lifting for electron microscopy

1978 ◽  
Vol 36 (2) ◽  
pp. 86-87
Author(s):  
Adrian F. van Dellen
Keyword(s):  
Infectious Disease ◽  
Electron Microscopy ◽  
Tissue Culture ◽  
Organ System ◽  
Surrounding Tissue ◽  
Paraffin Sections ◽  
Surface Areas ◽  
Specific Determination ◽  
High Degree ◽  
Accuracy And Repeatability

The morphologic pathologist may require information on the ultrastructure of a non-specific lesion seen under the light microscope before he can make a specific determination. Such lesions, when caused by infectious disease agents, may be sparsely distributed in any organ system. Tissue culture systems, too, may only have widely dispersed foci suitable for ultrastructural study. In these situations, when only a few, small foci in large tissue areas are useful for electron microscopy, it is advantageous to employ a methodology which rapidly selects a single tissue focus that is expected to yield beneficial ultrastructural data from amongst the surrounding tissue. This is in essence what "LIFTING" accomplishes. We have developed LIFTING to a high degree of accuracy and repeatability utilizing the Microlift (Fig 1), and have successfully applied it to tissue culture monolayers, histologic paraffin sections, and tissue blocks with large surface areas that had been initially fixed for either light or electron microscopy.

scholarly journals Escalation of Pyrethroid Resistance in the Malaria Vector Anopheles funestus Induces a Loss of Efficacy of Piperonyl Butoxide–Based Insecticide-Treated Nets in Mozambique

2019 ◽  
Vol 220 (3) ◽  
pp. 467-475 ◽  
Author(s):  
Jacob M Riveron ◽  
Silvie Huijben ◽  
Williams Tchapga ◽  
Magellan Tchouakui ◽  
Murielle J Wondji ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Pyrethroid Resistance ◽  
Anopheles Funestus ◽  
Resistance Mechanisms ◽  
Piperonyl Butoxide ◽  
Insecticide Treated Nets ◽  
Molecular Analyses ◽  
Cytochrome P450 Genes ◽  
High Degree ◽  
Long Lasting Insecticidal Nets

Abstract Background Insecticide resistance poses a serious threat to insecticide-based interventions in Africa. There is a fear that resistance escalation could jeopardize malaria control efforts. Monitoring of cases of aggravation of resistance intensity and its impact on the efficacy of control tools is crucial to predict consequences of resistance. Methods The resistance levels of an Anopheles funestus population from Palmeira, southern Mozambique, were characterized and their impact on the efficacy of various insecticide-treated nets established. Results A dramatic loss of efficacy of all long-lasting insecticidal nets (LLINs), including piperonyl butoxide (PBO)–based nets (Olyset Plus), was observed. This An. funestus population consistently (2016, 2017, and 2018) exhibited a high degree of pyrethroid resistance. Molecular analyses revealed that this resistance escalation was associated with a massive overexpression of the duplicated cytochrome P450 genes CYP6P9a and CYP6P9b, and also the fixation of the resistance CYP6P9a_R allele in this population in 2016 (100%) in contrast to 2002 (5%). However, the low recovery of susceptibility after PBO synergist assay suggests that other resistance mechanisms could be involved. Conclusions The loss of efficacy of pyrethroid-based LLINs with and without PBO is a concern for the effectiveness of insecticide-based interventions, and action should be taken to prevent the spread of such super-resistance.

scholarly journals Fast Antibiotic Susceptibility Testing via Raman Microspectrometry on Single Bacteria: An MRSA Case Study

ACS Omega ◽  
2021 ◽  
Author(s):  
Armelle Novelli Rousseau ◽  
Nicolas Faure ◽  
Fabian Rol ◽  
Zohreh Sedaghat ◽  
Joël Le Galudec ◽  
...  
Keyword(s):  
Antibiotic Susceptibility ◽  
Susceptibility Testing ◽  
Antibiotic Susceptibility Testing ◽  
Raman Microspectrometry

scholarly journals Longitudinal Characterization and Transmission Dynamics of Antibiotic-Resistant Organisms in an ICU (LOCATE AROs)

2020 ◽  
Vol 41 (S1) ◽  
pp. s42-s43
Author(s):  
Kimberley Sukhum ◽  
Candice Cass ◽  
Meghan Wallace ◽  
Caitlin Johnson ◽  
Steven Sax ◽  
...  
Keyword(s):  
Antibiotic Susceptibility ◽  
Environmental Samples ◽  
Susceptibility Testing ◽  
Marrow Transplant ◽  
Transmission Dynamics ◽  
Hospital Environment ◽  
Antibiotic Susceptibility Testing ◽  
Antibiotic Resistant ◽  
Clonal Group ◽  
Communal Areas

Background: Healthcare-associated infections caused by antibiotic-resistant organisms (AROs) are a major cause of significant morbidity and mortality. To create and optimize infection prevention strategies, it is crucial to delineate the role of the environment and clinical infections. Methods: Over a 14-month period, we collected environmental samples, patient feces, and patient bloodstream infection (BSI) isolates in a newly built bone marrow transplant (BMT) intensive care unit (ICU). Samples were collected from 13 high-touch areas in the patient room and 4 communal areas. Samples were collected from the old BMT ICU, in the new BMT ICU before patients moved in, and for 1 year after patients moved in. Selective microbiologic culture was used to isolate AROs, and whole-genome sequencing (WGS) was used to determine clonality. Antibiotic susceptibility testing was performed using Kirby-Bauer disk diffusion assays. Using linear mixed modeling, we compared ARO recovery across time and sample area. Results: AROs were collected and cultured from environmental samples, patient feces, and BSI isolates (Fig. 1a). AROs were found both before and after a patient entered the ICU (Fig. 1b). Sink drains had significantly more AROs recovered per sample than any other surface area (P < .001) (Fig. 1c). The most common ARO isolates were Pseudomonas aeruginosa and Stenotrophomonas maltophila (Fig. 1d). The new BMT ICU had fewer AROs recovered per sample than the old BMT ICU (P < .001) and no increase in AROs recovered over the first year of opening (P > .05). Furthermore, there was no difference before versus after patients moved into the hospital (P > .05). Antibiotic susceptibility testing reveal that P. aeruginosa isolates recovered from the old ICU were resistant to more antibiotics than isolates recovered from the new ICU (Fig. 2a). ANI and clonal analyses of P. aeruginosa revealed a large cluster of clonal isolates (34 of 76) (Fig. 2b). This clonal group included isolates found before patients moved into the BMT ICU and patient blood isolates. Furthermore, this clonal group was initially found in only 1 room in the BMT ICU, and over 26 weeks, it was found in sink drains in all 6 rooms sampled (Fig. 2b). Conclusions: AROs are present before patients move into a new BMT ICU, and sink drains act as a reservoir for AROs over time. Furthermore, sink-drain P. aeruginosa isolates are clonally related to isolates found in patient BSIs. Overall, these results provide insight into ARO transmission dynamics in the hospital environment.Funding: Research reported in this publication was supported by the Washington University Institute of Clinical and Translational Sciences grant UL1TR002345 from the National Center for Advancing Translational Sciences (NCATS) of the National Institutes of Health (NIH). The content is solely the responsibility of the authors and does not necessarily represent the official view of the NIH.Disclosures: None

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