scholarly journals A Statistical Approach for Determination of Disk Diffusion-Based Cutoff Values for Systematic Characterization of Wild-Type and Non-Wild-Type Bacterial Populations in Antimicrobial Susceptibility Testing

2015 ◽  
Vol 53 (6) ◽  
pp. 1812-1822 ◽  
Author(s):  
Giorgia Valsesia ◽  
Malgorzata Roos ◽  
Erik C. Böttger ◽  
Michael Hombach
Keyword(s):  
Resistance Mechanisms ◽  
Beta Lactamase ◽  
Wild Type ◽  
Beta Lactam ◽  
Bacterial Populations ◽  
Content Type ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli

In this study, we introduce a new approach for determination of epidemiologic cutoffs (ECOFFs) and resistant-population cutoffs (RCOFFs) based on receiver operating characteristic (ROC) curves. As an example, the method was applied for determination of ECOFFs for seven different beta-lactam antibiotics and wild-type populations ofEscherichia coli,Klebsiella pneumoniae, andEnterobacter cloacae. In addition, RCOFFs were determined for bacterial populations with defined resistance mechanisms (“resistotypes”), i.e., extended-spectrum beta-lactamase (ESBL)-positiveE. coli, ESBL-positiveK. pneumoniae, and ESBL-positiveE. cloacae; AmpC cephalosporinase-positiveE. coliand AmpC-positiveK. pneumoniae; and broad-spectrum beta-lactamase (BSBL)-positiveE. coli. RCOFFs and ECOFFs are instrumental for a systematic characterization of associations between resistotypes and wild-type populations.

scholarly journals The Resistant-Population Cutoff (RCOFF): a New Concept for Improved Characterization of Antimicrobial Susceptibility Patterns of Non-Wild-Type Bacterial Populations

2015 ◽  
Vol 53 (6) ◽  
pp. 1806-1811 ◽  
Author(s):  
Giorgia Valsesia ◽  
Michael Hombach ◽  
Florian P. Maurer ◽  
Patrice Courvalin ◽  
Malgorzata Roos ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Resistance Mechanisms ◽  
Clinical Strain ◽  
Wild Type ◽  
Bacterial Populations ◽  
Content Type ◽  
Resistant Population ◽  
Susceptibility Patterns

This study aimed to determine resistant-population cutoffs (RCOFFs) to allow for improved characterization of antimicrobial susceptibility patterns in bacterial populations. RCOFFs can complement epidemiological cutoff (ECOFF)-based settings of clinical breakpoints (CBPs) by systematically describing the correlation between non-wild-type and wild-type populations. We illustrate this concept by describing three paradigmatic examples of wild-type and non-wild-typeEscherichia colipopulations from our clinical strain database of disk diffusion diameters. The statistical determination of RCOFFs and ECOFFs and their standardized applications in antimicrobial susceptibility testing (AST) facilitates the assignment of isolates to wild-type or non-wild-type populations. This should improve the correlation ofin vitroAST data and distinct antibiotic resistance mechanisms with clinical outcome facilitating the setting and validation of CBPs.

scholarly journals PREVALENCE OF CEPHALOSPORIN-RESISTANT GRAM-NEGATIVE BACILLI FROM CLINICAL SAMPLES

2016 ◽  
pp. 176
Author(s):  
Kavi Aniis ◽  
Rajamanikandan Kcp ◽  
Arvind Prasanth D
Keyword(s):  
Clinical Samples ◽  
Beta Lactamase ◽  
Bacterial Isolates ◽  
Beta Lactam ◽  
Gram Negative ◽  
Beta Lactamases ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Lactam Ring ◽  
Esbl Producers

<p>ABSTRACT<br />Objective: Beta-lactams are the group of antibiotics that contain a ring called as “beta-lactam ring,” which is responsible for the antibacterial activity.<br />The presence of resistance among Gram-negative organisms is due to the production of beta-lactamases enzymes that hydrolysis the beta-lactam ring<br />thereby conferring resistance to the organism. This study is undertaken to determine the prevalence of extended-spectrum beta-lactamase (ESBL)<br />producing Gram-negative organism from clinical samples.<br />Methods: A total of 112 clinical samples were taken for this study. The combined disc synergistic test (CDST) was used for the phenotypic detection<br />of ESBL producers from the clinical samples. The genotypic identification of ESBL producers was carried out by alkaline lysis method by isolation of<br />plasmid DNA.<br />Result: A total of 87 bacterial isolates were isolated and identified. Among them, Klebsiella (41%) was the predominant organism followed by<br />Escherichia coli (33%), Proteus (10%), Pseudomonas (10%), and Serratia (6%). Among the various bacterial isolates, Klebsiella showed a higher<br />percentage of resistance. The CDST showed that 8 isolates of Klebsiella, 3 isolates of E. coli, and 1 isolate of Pseudomonas were found to be ESBL<br />producers. The genotypic confirmation showed that the two bacterial isolates, namely, Klebsiella and E. coli were found to possess temoniera (TEM)<br />gene which was the 400-500 bp conferring resistance to the antibiotics.<br />Conclusion: The results of this study suggest that early detection of ESBL producing Gram-negative organism is a very important step in planning the<br />therapy of patient in Hospitals. CDST continues to be a good indicator in the detection of ESBL producers.<br />Keywords: Beta-lactamases, Gram-negative bacilli, Extended-spectrum beta-lactamase, Resistance, Combined disc synergistic test.</p><p> </p>

scholarly journals Molecular characterization of extended-spectrum beta-lactamase producing Enterobacteriaceae in a Saudi Arabian tertiary hospital

2014 ◽  
Vol 8 (03) ◽  
pp. 282-288 ◽  
Author(s):  
Hoda Hassan ◽  
Baha Abdalhamid
Keyword(s):  
Tertiary Hospital ◽  
Multidrug Resistant ◽  
Beta Lactamase ◽  
M Gene ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Extended Spectrum ◽  
Vitek 2 ◽  
High Level

Introduction: The aim of this study was to determine the prevalence of extended-spectrum beta-lactamase (ESBL) producing Escherichia coli (E. coli), Klebsiella pneumoniae (K. pneumoniae), and Proteus mirabilis (P. mirabilis). In addition, different methods for detection of these enzymes, including the newly introduced CHROMagar ESBL, were evaluated. Methodology: A total of 382 Enterobacteriaceae clinical isolates were obtained from King Fahad Specialist Hospital – Dammam, during 2011 and screened for production of ESBL using advanced expert system of Vitek 2, CHROMagar and ESBL-E-strips. PCR assay was used to detect blaTEM, blaSHV, and blaCTX-M genes. Susceptibility to a panel of antibiotics was determined. Results: The overall proportion of ESBL-producing enterobacterial isolates was 30.6%, which was higher in E. coli (35.8%) than in K. pneumoniae (25.7%). ESBL genotypes showed remarkable increase in the CTX-M (97.4%) compared to SHV (23.1%). The predominant ESBL was CTX-M- 15 (92.1 %). No TEM ESBL was detected in this study. The Vitek2 showed the highest sensitivity (100%), and the CHROMagar had the lowest specificity (97.3%) compared to the molecular method. All isolates were susceptible to imipenem and meropenem. Conclusions: This study confirms a high level of blaCTX-M positive ESBL isolates are circulating in the Eastern Province of Saudi Arabia. The trend of a multidrug-resistant profile associated with the recovery of the blaCTX-M gene is alarming.

Occurrence of beta-lactamase producing Escherichia coli in healthy and diarrhoeic dogs in Andhra Pradesh, India

2018 ◽  
Author(s):  
N. Mohammad Sharif ◽  
B. Sreedevi ◽  
R. K. Chaitanya ◽  
Ch. Srilatha
Keyword(s):  
Escherichia Coli ◽  
Andhra Pradesh ◽  
Diffusion Method ◽  
Beta Lactamase ◽  
Beta Lactam ◽  
Beta Lactams ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Healthy Dogs ◽  
Group 2

The present study was carried out to characterize beta-lactam resistance in Escherichia coli isolated from healthy and diarrhoeic dogs. A total of 93 E. coli were isolated from the rectal swabs of 136 dogs (60/92 of healthy dogs and 33/44 of diarrhoeic dogs). Predominant serotypes detected include rough (19 isolates), O141 (5), O9 (2), O126 (2), O128 (2), O15, O20, O35, O49, O63, O85, O101, O116, O117, O118, O119 (1 isolate each) and the rest of 52 isolates were untypable (UT). Disc diffusion method revealed resistance to cefotaxime (41.9%), ceftriaxone (34.4%), ceftazidime (30.1%) and aztreonam (18.2%). Overall frequency of extended spectrum beta-lactamase (ESBL) phenotype was found to be 29% (27/93). Beta-lactamase genes detected include blaAmpC (86.0%), blaSHV (30.1%), blaCTX-M group-1 (19.3%), blaTEM (17.2%), blaOXA (13.9%) and blaCTX-M group-2 (7.5%). The study revealed resistance to commonly prescribed beta-lactams, with ESBL phenotype in E. coli of canine origin in Andhra Pradesh, India.

scholarly journals Whole-Genome Multilocus Sequence Typing of Extended-Spectrum-Beta-Lactamase-Producing Enterobacteriaceae

2016 ◽  
Vol 54 (12) ◽  
pp. 2919-2927 ◽  
Author(s):  
Marjolein F. Q. Kluytmans-van den Bergh ◽  
John W. A. Rossen ◽  
Patricia C. J. Bruijning-Verhagen ◽  
Marc J. M. Bonten ◽  
Alexander W. Friedrich ◽  
...  
Keyword(s):  
Multilocus Sequence Typing ◽  
Klebsiella Oxytoca ◽  
Whole Genome ◽  
Beta Lactamase ◽  
Typing Method ◽  
Content Type ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Extended Spectrum ◽  
Species Specific

Molecular typing has become indispensable in the detection of nosocomial transmission of bacterial pathogens and the identification of sources and routes of transmission in outbreak settings, but current methods are labor-intensive, are difficult to standardize, or have limited resolution. Whole-genome multilocus sequence typing (wgMLST) has emerged as a whole-genome sequencing (WGS)-based gene-by-gene typing method that may overcome these limitations and has been applied successfully for several species in outbreak settings. In this study, genus-, genetic-complex-, and species-specific wgMLST schemes were developed forCitrobacterspp., theEnterobacter cloacaecomplex,Escherichia coli,Klebsiella oxytoca, andKlebsiella pneumoniaeand used to type a national collection of 1,798 extended-spectrum-beta-lactamase-producingEnterobacteriaceae(ESBL-E) isolates obtained from patients in Dutch hospitals. Genus-, genetic-complex-, and species-specific thresholds for genetic distance that accurately distinguish between epidemiologically related and unrelated isolates were defined forCitrobacterspp., theE. cloacaecomplex,E. coli, andK. pneumoniae. wgMLST was shown to have higher discriminatory power and typeability thanin silicoMLST. In conclusion, the wgMLST schemes developed in this study facilitate high-resolution WGS-based typing of the most prevalent ESBL-producing species in clinical practice and may contribute to further elucidation of the complex epidemiology of antimicrobial-resistantEnterobacteriaceae. wgMLST opens up possibilities for the creation of a Web-accessible database for the global surveillance of ESBL-producing bacterial clones.

scholarly journals Characterization of Multidrug Resistant Extended-Spectrum Beta-Lactamase-ProducingEscherichia coliamong Uropathogens of Pediatrics in North of Iran

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Mohammad Sadegh Rezai ◽  
Ebrahim Salehifar ◽  
Alireza Rafiei ◽  
Taimour Langaee ◽  
Mohammadreza Rafati ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Multidrug Resistant ◽  
Beta Lactamase ◽  
Beta Lactam ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Beta Lactam Antibiotics ◽  
Extended Spectrum ◽  
Extended Spectrum Beta Lactamases ◽  
North Of Iran

Escherichia coliremains as one of the most important bacteria causing infections in pediatrics and producing extended-spectrum beta-lactamases (ESBLs) making them resistant to beta-lactam antibiotics. In this study we aimed to genotype ESBL-producingE. coliisolates from pediatric patients for ESBL genes and determine their association with antimicrobial resistance. One hundred of theE. coliisolates were initially considered ESBL producing based on their MIC results. These isolates were then tested by polymerase chain reaction (PCR) for the presence or absence ofCTX,TEM,SHV,GES, andVEBbeta-lactamase genes. About 30.5% of isolatedE. coliwas ESBL-producing strain. TheTEMgene was the most prevalent (49%) followed bySHV(44%),CTX(28%),VEB(8%), andGES(0%) genes. The ESBL-producingE. coliisolates were susceptible to carbapenems (66%) and amikacin (58%) and showed high resistance to cefixime (99%), colistin (82%), and ciprofloxacin (76%). In conclusion, carbapenems were the most effective antibiotics against ESBl-producingE. coliin urinary tract infection in North of Iran. The most prevalent gene is the TEM-type, but the other resistant genes and their antimicrobial resistance are on the rise.

scholarly journals Intercontinental spread of OXA-48 beta-lactamase-producing Enterobacteriaceae over a 11-year period, 2001 to 2011

2013 ◽  
Vol 18 (31) ◽  
Author(s):  
A Potron ◽  
L Poirel ◽  
E Rondinaud ◽  
P Nordmann
Keyword(s):  
Mediterranean Area ◽  
Beta Lactamase ◽  
Beta Lactam ◽  
North African ◽  
African Countries ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Beta Lactam Antibiotics ◽  
North African Countries ◽  
Sequence Types

OXA-48 beta-lactamase producers are emerging as an important threat mostly in the Mediterranean area. We report here the molecular epidemiology of a collection of OXA-48 beta-lactamase-positive enterobacterial isolates (n=107) recovered from European and north-African countries between January 2001 and December 2011. This collection included 67 Klebsiella pneumoniae, 24 Escherichia coli and 10 Enterobacter cloacae. Using the EUCAST breakpoints, ninety-eight isolates (91.6%) were of intermediate susceptibility or resistant to ertapenem, whereas 66% remained susceptible to imipenem. Seventy-five per cent of the isolates co-produced an extended-spectrum beta-lactamase, most frequently CTX-M-15 (77.5%). Susceptibility testing to non-beta-lactam antibiotics showed that colistin, tigecycline, amikacin, and fosfomycin remain active against most of the isolates. Multilocus sequence typing indicated that the most common sequence types (ST) were ST101 and ST38 for K. pneumoniae and E. coli, respectively. The blaOXA-48 gene was located on a 62 kb IncL/M plasmid in 92.5% of the isolates, indicating that a single plasmid was mainly responsible for the spread of that gene. In addition, this study identified multiple cases of importation of OXA-48 beta-lactamase producers at least in Europe, and spread of OXA-48 beta-lactamase producers giving rise to an endemic situation, at least in France.

scholarly journals First Global Report of Plasmid-Mediated mcr-1 and Extended-Spectrum Beta-Lactamase-Producing Escherichia coli from Sheep in Portugal

Antibiotics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1403
Author(s):  
Josman Dantas Palmeira ◽  
Marisa Haenni ◽  
Jean-Yves Madec ◽  
Helena Maria Neto Ferreira
Keyword(s):  
One Health ◽  
Diffusion Method ◽  
Beta Lactamase ◽  
Beta Lactam ◽  
Colistin Resistance ◽  
Disk Diffusion Method ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Beta Lactam Antibiotics ◽  
Extended Spectrum

Resistances to extended-spectrum cephalosporins (ESC) and colistin are One Health issues since genes encoding these resistances can be transmitted between all sectors of the One Health concept, i.e., human, animal, and the environment. Among food-producing animals, sheep farming has long been overlooked. To fill in this knowledge gap, we looked for ESC- and colistin resistance in 21 faecal samples collected from sheep in one farm in the south of Portugal. ESC-resistant isolates were selected on MacConkey agar plates supplemented with cefotaxime. Susceptibility testing was performed by the disk-diffusion method according to CLSI, while colistin MIC was determined by broth microdilution. ESC- and colistin-resistance genes were identified by PCR, and the clonality of all isolates was assessed by XbaI-PFGE. The replicon content was determined by PCR according to the PCR-based replicon typing (PBRT) scheme. Sixty-two non-duplicate ESC-resistant E. coli isolates were identified, which all presented an extended-spectrum beta-lactamase (ESBL) phenotype, mostly due to the presence of CTX-M genes. One CTX-M-1-producing E. coli was concomitantly colistin-resistant and presented the plasmid-mediated mcr-1 gene. Nearly all isolates showed associated resistances to non-beta-lactam antibiotics, which could act as co-selectors, even in the absence of beta-lactam use. The results showed a high proportion of ESBL-producing E. coli in sheep faeces. Their dissemination was very dynamic, with the spread of successful clones between animals, but also a large diversity of clones and plasmids, sometimes residing in the same animal. This study highlights the need for global surveillance in all food-producing sectors, in order to avoid the dissemination of genes conferring resistance to last-resort antibiotics in human medicine.

scholarly journals Molecular Detection of Extended Spectrum Beta-lactamase Resistance in Escherichia coli from Poultry Droppings in Karu, Nasarawa State, Nigeria

2021 ◽  
pp. 31-42
Author(s):  
S. C. Tama ◽  
Y. B. Ngwai ◽  
G. R. I. Pennap ◽  
I. H. Nkene ◽  
R. H. Abimiku
Keyword(s):  
Escherichia Coli ◽  
Molecular Detection ◽  
Beta Lactamase ◽  
Beta Lactam ◽  
Cross Sectional ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Extended Spectrum ◽  
Microbiological Methods ◽  
Poultry Droppings

Aims: This study investigates and reports the production of extended spectrum beta-lactamase in Escherichia coli isolates in poultry droppings sourced from selected poultry farms in Karu, Nigeria Study Design:  Cross sectional study Place and Duration of Study: Department of Microbiology, Nasarawa State University, Keffi, between August 2019 and February 2020. Methodology: Escherichia coli was isolated from the samples using standard cultural and microbiological methods. Antibiotic susceptibility testing and minimum inhibitory concentrations were evaluated as described by the Clinical and Laboratory Standards Institute (CLSI). The detection of ESBL production in E. coli isolates was carried out using double disc synergy test.  In addition, molecular detection of ESBL genes was carried out using Polymerase Chain Reaction (PCR) method. Results: All (100%) samples collected had E. coli. Antibiotic resistances in the isolates in decreasing order were as follows: ampicillin (96.7%), streptomycin (94.4%), sulphamethoxazole /trimethoprim (87.8%), amoxicillin/ clavulanic acid (61.1%), gentamicin (52.2%), ciprofloxacin (40.0%), ceftazidime (35.6%), cefotaxime (31.1%), imipenems (22.2%), cefoxitin (13.3%). The commonest antibiotic resistant phenotype was AMP-SXT-S-CTX-CN (8.8%). Multiple antibiotic resistance (MAR) was observed in 92.2% (83/90) of the isolates with the common MAR indices being 0.5 (26.5%), 0.6 (19.2%), 0.4 (13.2%) and 0.9 (10.8%). Fifty nine of the eighty beta-lactam resistant isolates (73.7%) were confirmed ESBL producers. 55 of the 59 ESBL positive isolates (93.2%) carried bla genes as follows:   blaSHV (50/55, 90.9%), blaTEM (31/55, 56.3%) and blaCTX-M (46/55, 83.6%). Thirty six (65.5%) of the 55 isolates carried two bla genes (blaSHV and blaTEM, blaTEM and blaCTX-M, and blaCTX-M and blaSHV). Conclusion: The E. coli isolates showed lower resistances to cefoxitin, imipenem, cefotaxime, ceftazidime, and ciprofloxacin and most isolates were MAR, with resistance to 5 antibiotics being the most predominant. In addition, blaSHV gene was the most common ESBL gene detected in the confirmed ESBL-producing E. coli isolates.

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