scholarly journals A Rapid ATP Bioluminescence-based Test for Detecting Levofloxacin Resistance Starting from Positive Blood Culture Bottles

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Atsushi Matsui ◽  
Hideki Niimi ◽  
Yuichi Uchiho ◽  
Shunsuke Kawabe ◽  
Hideyuki Noda ◽  
...  
Keyword(s):  
Blood Culture ◽  
Positive Blood Culture ◽  
Antimicrobial Susceptibility ◽  
Bacterial Suspension ◽  
Antimicrobial Susceptibility Test ◽  
Additional Information ◽  
Atp Bioluminescence ◽  
Antimicrobial Susceptibility Tests ◽  
Turbidity Method ◽  
Susceptibility Tests

Abstract Administering appropriate antimicrobial therapy as early as possible is important for rescuing bacteremic patients. Therefore, rapid antimicrobial susceptibility tests in positive blood culture specimens have been diligently sought. Adenosine triphosphate (ATP) bioluminescence-based methods have been used for rapid antimicrobial susceptibility tests. However, blood culture specimens have not been examined in many studies, possibly due to abundant intracellular ATP in blood corpuscles resulting in false-susceptible results. In this study, we developed a rapid ATP bioluminescence-based method for detecting antibiotic resistance starting from positive blood culture. To minimize background ATP originating from blood corpuscles, specimens were centrifuged and the supernatant diluted with broth, and an ATP-eliminating reagent was then added to the bacterial suspension at the beginning of incubation. This newly devised procedure reduced the background ATP by more than five orders of magnitude. In a pilot study using levofloxacin, no false-susceptible results were observed in 15 clinical specimens. Furthermore, the results indicated that the rapid method provided additional information about bacterial activities with high resolution, in contrast to the less-thorough findings with the conventional turbidity method. Therefore, our approach will contribute to the treatment of infectious diseases as a rapid antimicrobial susceptibility test.

scholarly journals A fast impedance-based antimicrobial susceptibility test

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Daniel C. Spencer ◽  
Teagan F. Paton ◽  
Kieran T. Mulroney ◽  
Timothy J. J. Inglis ◽  
J. Mark Sutton ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Mode Of Action ◽  
Bacterial Species ◽  
Susceptibility Test ◽  
Electrical Characteristics ◽  
Label Free ◽  
Broth Microdilution ◽  
Antimicrobial Susceptibility Test ◽  
Antimicrobial Susceptibility Tests ◽  
Susceptibility Tests

Abstract There is an urgent need to develop simple and fast antimicrobial susceptibility tests (ASTs) that allow informed prescribing of antibiotics. Here, we describe a label-free AST that can deliver results within an hour, using an actively dividing culture as starting material. The bacteria are incubated in the presence of an antibiotic for 30 min, and then approximately 105 cells are analysed one-by-one with microfluidic impedance cytometry for 2–3 min. The measured electrical characteristics reflect the phenotypic response of the bacteria to the mode of action of a particular antibiotic, in a 30-minute incubation window. The results are consistent with those obtained by classical broth microdilution assays for a range of antibiotics and bacterial species.

scholarly journals A fast impedance-based antimicrobial susceptibility test

2020 ◽  
Author(s):  
Daniel C. Spencer ◽  
Teagan Paton ◽  
Timothy J.J. Inglis ◽  
J. Mark Sutton ◽  
Hywel Morgan
Keyword(s):  
Antimicrobial Susceptibility ◽  
Starting Material ◽  
Susceptibility Test ◽  
Label Free ◽  
Antimicrobial Susceptibility Test ◽  
Antimicrobial Susceptibility Tests ◽  
Susceptibility Tests

Abstract There is an urgent need to develop simple and fast antimicrobial susceptibility tests that allow informed prescribing of antibiotics. In this protocol we describe a method for a label-free AST that can deliver results within an hour, using an actively dividing culture as starting material.

scholarly journals Shortening the Time of the Identification and Antimicrobial Susceptibility Testing on Positive Blood Cultures with MALDI-TOF MS

Diagnostics ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1514
Author(s):  
Ya-Wen Tsai ◽  
Ting-Chia Lin ◽  
Hsiu-Yin Chou ◽  
Huei-Ya Hung ◽  
Che-Kim Tan ◽  
...  
Keyword(s):  
Blood Culture ◽  
Antimicrobial Susceptibility ◽  
Turnaround Time ◽  
Identification Accuracy ◽  
Intermediate Step ◽  
Short Term ◽  
Antimicrobial Susceptibility Tests ◽  
Susceptibility Tests ◽  
Optimal Incubation ◽  
Average Turnaround Time

The current processes used in clinical microbiology laboratories take ~24 h for incubation to identify the bacteria after the blood culture has been confirmed as positive and fa further ~24 h to report the results of antimicrobial susceptibility tests (ASTs). Patients with suspected bloodstream infection are treated with empiric broad-spectrum antibiotics but delayed targeted antimicrobial therapy. This study aimed to develop a method with a significantly shortened turnaround time for clinical application by identifying the optimal incubation period of a subculture. A total of 188 positive blood culture samples obtained from Nov. 2019 to Aug. 2020 were included. Compared to the conventional 24-h incubation for bacterial identification, our approach achieved 96.1% and 97.4% identification accuracy after shortening the incubation time to 4.5 and 3.5 h for gram-positive (GP) and gram-negative (GN) bacterial samples, respectively. Samples from short-term incubation without any intermediate step or process were directly subjected to analysis with the Phoenix M50 AST. Compared to the conventional disk diffusion AST, the category agreements for GP (excluding Streptococcus spp.), Streptococcus spp., and GN bacterial samples were 91.8%, 97.5%, and 92.7%, respectively. Our approach significantly reduced the average turnaround time from 48 h to 28 h for reporting bacterial identity and decreased average AST from 72 h to 50.3 h compared to the conventional methods. Accordingly, this approach allows a physician to prescribe the appropriate antibiotic(s) ~21.7 h earlier, thereby improving patient outcomes.

scholarly journals Diagnosis and Treatment of Human Salmonellosis in Addis Ababa City, Ethiopia

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Legesse Garedew ◽  
Semaria Solomon ◽  
Yoseph Worku ◽  
Hilina Worku ◽  
Debela Gemeda ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Addis Ababa ◽  
Clinical Signs ◽  
Diagnosis And Treatment ◽  
Widal Test ◽  
Predictive Values ◽  
Blood Samples ◽  
Antimicrobial Susceptibility Tests ◽  
Stool Samples ◽  
Susceptibility Tests

Background. Diagnosis using reliable tools and treatment followingin vitroantimicrobial susceptibility tests are critical to proper addressing of antibiotic-resistantSalmonellainfection.Methodology. A cross-sectional study was conducted to assess the practice of diagnosis and treatment of salmonellosis in Addis Ababa. Tube Widal test (for blood samples only), culture, biochemical and carbohydrate fermentation, serotyping, and antimicrobial susceptibility tests were employed for both blood and stool samples.Results. Of all the diseases listed in the diagnosis, nontyphoidal (n=72, 13.71%) and typhoidal (n=47, 8.95%) salmonellosis were the second and third common diseases. Among the 288 blood samples, almost half were positive for O, H, or both antigens. However, only 1 (0.68%) of the positive blood samples yieldedSalmonellaisolate during culture. The study demonstrated low specificity (0.68%) and positive predictive value (48.78%) of Widal test. Conversely, the test showed 100% sensitivity and negative predictive values.Salmonellaisolates were identified from 7 (7.07%) of 99 stool samples. Two-thirds of salmonellosis suspected patients received antibiotic treatment. However, only half of the confirmed salmonellosis patients were treated with appropriate antibiotics. All of the isolates were susceptible to ciprofloxacin and ceftriaxone but resistant to ampicillin.Conclusions. Majority of the patients who participated in this study were wrongly diagnosed using symptoms, clinical signs, and tube Widal test. Consequently, most of the patients received inappropriate treatment.

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