Rapid Antibiotic Susceptibility Testing of Pathogenic Bacteria Using Heavy-Water-Labeled Single-Cell Raman Spectroscopy in Clinical Samples

2019 ◽  
Vol 91 (9) ◽  
pp. 6296-6303 ◽  
Author(s):  
Kai Yang ◽  
Hong-Zhe Li ◽  
Xuan Zhu ◽  
Jian-Qiang Su ◽  
Bin Ren ◽  
...  
2021 ◽  
Author(s):  
◽  
Immaculate Nabawanuka

Background: The transmission of diseases caused by pathogenic bacteria is still a threat. One of the potential sources of bacterial diseases is the door handles. This study aimed at isolating, identifying bacteria, determining total bacterial load, and determining antibiotic susceptibility patterns of bacteria obtained from door handles in Makerere university. Methodology:  A total of 60 samples randomly scattered within the university were swabbed and analyzed for bacterial growth. Samples were inoculated on MacConkey and blood agar and then incubated at 37 ºC for 24 hours. All sample isolates were sub cultured and identified based on macro and micromorphology, and standard biochemical tests. The establishment of the total bacterial load was done using the standard plate count method. Antibiotic susceptibility testing was done using the disc diffusion method on Muller Hilton agar. Results: The following bacterial species and genera were obtained from door handles, staphylococcus aureus (30.8%), Coagulase-negative staphylococcus (12.0%), Streptococcus species (24.2%), Escherichia coli (7.7%), Pseudomonas aeruginosa (14.3%), bacilli species (11.0%). The study showed that there was a significant difference in the prevalence of bacilli species (p= 0.017) and E. coli (p= 0.015) among the study group. The results from total bacterial count indicated that toilet door handles had the highest bacterial load compared to office door handles and classrooms. Antibiotic susceptibility testing of isolates showed that all bacteria were resistant and intermediately resistant to commonly used antibiotics except for Escherichia coli that was susceptible to amoxicillin Conclusion and recommendations: The study reveals that door handles are a considerable source of pathogenic bacteria thus play a major role in the transmission of diseases caused by such bacteria. Further studies could be done and different study groups could be included for example routinely opened doors and the doors which are not routinely opened.


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Chi-Sing Ho ◽  
Neal Jean ◽  
Catherine A. Hogan ◽  
Lena Blackmon ◽  
Stefanie S. Jeffrey ◽  
...  

Abstract Raman optical spectroscopy promises label-free bacterial detection, identification, and antibiotic susceptibility testing in a single step. However, achieving clinically relevant speeds and accuracies remains challenging due to weak Raman signal from bacterial cells and numerous bacterial species and phenotypes. Here we generate an extensive dataset of bacterial Raman spectra and apply deep learning approaches to accurately identify 30 common bacterial pathogens. Even on low signal-to-noise spectra, we achieve average isolate-level accuracies exceeding 82% and antibiotic treatment identification accuracies of 97.0±0.3%. We also show that this approach distinguishes between methicillin-resistant and -susceptible isolates of Staphylococcus aureus (MRSA and MSSA) with 89±0.1% accuracy. We validate our results on clinical isolates from 50 patients. Using just 10 bacterial spectra from each patient isolate, we achieve treatment identification accuracies of 99.7%. Our approach has potential for culture-free pathogen identification and antibiotic susceptibility testing, and could be readily extended for diagnostics on blood, urine, and sputum.


2021 ◽  
Author(s):  
Wenshuai Wu ◽  
Gaozhe Cai ◽  
Yang Liu

On-site single-cell antibiotic susceptibility testing (sc-AST) provides unprecedented technical potential to improve the treatment of bacterial infections and study heterogeneous resistance to antibiotics. Herein, we developed a portable and high-integrated 3D polydimethylsiloxane (PDMS) chip to perform fast and on-site bacteria quantification and sc-AST. The 3D arrangement of the chambers significantly improved the integration of reaction units (~10000/cm2) and widened the dynamic range to 5 orders of magnitude. A capillary valve-based flow distributor was adopted for flow equidistribution in 64 parallel channels and uniform sample loading in as short as 2 s. The degassed PDMS enabled this device to independently dispense the sample into 3D chamber array with almost 100% efficiency. The quantification of Escherichia coli (E. coli) strains with various activity was accomplished in 0.5-2 h, shortened by 20 h in comparison to the traditional plate counting. The functionality of our platform was demonstrated with several effective antibiotics by determining minimum inhibitory concentrations at single-cell level. Furthermore, we utilized the lyophilization of test reagents and needle-mediated reagents rehydration to realize one-step on-site sc-AST. The results indicate that the proposed sc-AST platform is portable, highly sensitive, fast, accurate and user-friendly, thus it has the potential to facilitate precise therapy in time and monitor the treatment. Meanwhile, it could serve as an approach for investigating the mechanisms of heteroresistance at single-cell resolution.


Author(s):  
Javid Sisakhtpour ◽  
Fatemeh Savaheli Moghadam ◽  
Sepideh Khodaparast ◽  
Nima Khoramabadi ◽  
Ashraf Mohabati Mobarez

Background. Clostridium (Clostridioides) difficile is recognized as the major cause of healthcare antibiotic-associated diarrhea. We surveyed a molecular epidemiological correlation between the clinical isolates from two general hospitals in Iran through clustering toxigenic types and antibiotic susceptibility testing (AST) accuracy. Methods. Study population included 460 diarrhoeic specimens from inpatients with a history of antibiotic therapy. All samples underwent enriched anaerobic culture, confirmed by detection of gluD gene with PCR. Toxin status and AST were assessed by the disk diffusion method (DDM) and minimal inhibitory concentrations (MICs) of metronidazole, vancomycin, and rifampin. C. difficile outbreak was analyzed through conventional PCR by tracing toxin genes and Homebrew pulsed-field gel electrophoresis (PFGE) for characterizing isolates within our healthcare systems. Results. A total of 29 C. difficile strains were isolated by enriched anaerobic culture from the clinical samples. Among them, 22 (4.8%) toxigenic profiles yielded toxins A and B (tcdA, tcdB) and binary toxins (cdtA, cdtB). The minimum inhibitory concentration (MIC) was 18.1% and 9% for vancomycin and metronidazole, and all isolates were susceptible to rifampicin and its minimum inhibitory concentration was at <0.003 μg/mL. The most dominant toxigenic and antibiotic-resistant “pulsotype F” was detected through PFGE combined with multiple Clostridial toxigenic pattern and AST. Conclusions. DNA fingerprinting studies represent a powerful tool in surveying hypervirulent C. difficile strains in clinical settings. Resistance to vancomycin and metronidazole, as first-line antibiotics, necessitate accomplishment of proper control strategies and also prescription of tigecycline as a more appropriate option.


Author(s):  
Jeevan Shetty ◽  
Zarrin Afroz

Background: Clindamycin is an important drug used in the treatment of Methicillin Sensitive Staphylococcus aureus (MSSA) as well as in Methicillin-resistant Staphylococcus aureus (MRSA) infections. This drug is widely used in the treatment of skin and soft tissue infections caused by them. Therapeutic failure caused by macrolide-lincosamine-streptogramin B constitutive and inducible clindamycin resistance (MLSBc and MLSBi) is being more commonly reported.Methods: The present study was conducted over a period of six months from October 2016 to March 2017 to know the incidence of MLSBc and MLSBi in Staphylococcus aureus (S. aureus) isolates obtained in our hospital by D-test as per CLSI guidelines. A total of 130 isolates of S.aureus were obtained from different clinical specimens which included pus/ wound swab (n=266), urine (n=577), sputum (n=225), blood (n=221), throat swab (n=71), ear/eye discharge (n=21), high vaginal swab (n=20) and body fluids (n=50). All the isolates were subjected to antibiotic sensitivity testing by Kirby Bauer’s disc diffusion method. Amoxyclav, Erythromycin, Clindamycin, Co-trimoxazole, Tetracycline, Ofloxacin, Gentamicin, Linezolid and Vancomycin were the antibiotics used.Results: Out of 130 (8.9%) isolates of S. aureus obtained from 1451 clinical samples, 82 (63.1%) were found to be MSSA and 48 (36.9%) were MRSA. Among S. aureus, 43 (33.1%) isolates showed MLSBc resistance, 22 (16.9%) isolates showed MLSBi resistance and 20 (15.4%) isolates showed MS phenotype. The remaining 45 (34.6%) isolates remained sensitive to Erythromycin. Among MSSA, MLSBc were observed in 18 (22%) isolates and MLSBi in 9 (11%) while in MRSA, MLSBc were observed in 25 (52.1%) isolates and MLSBi in 13 (27.1%) isolates. Almost all clinical isolates showed 100% sensitivity to Vancomycin and Linezolid in routine antibiotic susceptibility testing. Both MLSBc and MLSBi resistance was significantly higher (p<0.05) in MRSA than in MSSA.Conclusions: The study emphasizes the importance of conducting D test along with routine antibiotic susceptibility testing for better utilization of clindamycin in S. aureus infections.


Lab on a Chip ◽  
2013 ◽  
Vol 13 (2) ◽  
pp. 280-287 ◽  
Author(s):  
Jungil Choi ◽  
Yong-Gyun Jung ◽  
Jeewoo Kim ◽  
Sungbum Kim ◽  
Yushin Jung ◽  
...  

Author(s):  
Archana Bhimrao Wankhade ◽  
Sanjibkumar Panda ◽  
Riddhi Hathiwala ◽  
Yogendra Keche

Background: Staphylococcus aureus is a pathogen causing wide spectrum of infections. It has tendency for the development of multidrug resistance thereby exposing the selection of appropriate treatment. Therefore, the present study was undertaken to find out the antibiotic susceptibility pattern of Staphylococcus aureus isolated from various clinical samples in teaching tertiary hospital.Methods: Total 85 Staphylococcus aureus was isolated from clinical samples (pus, urine, sputum and blood) tested. Identification of Staphylococcus aureus was done by standard conventional microbiological methods. Antibiotic susceptibility testing was done by using disk diffusion method as per CLSI guidelines.Results: Staphylococcus aureus was isolated maximum from pus samples followed by urine samples. Antibiotic susceptibility testing showed highest resistance against Penicillin (69%) and Erythromycin (51%) followed by Cotrimoxazole (50%) & Nitrofurantoin (50%). All the strains were sensitive to Vancomycin. Amongst the urine isolates all were sensitive to Norfloxacin. These percentages of sensitivities are characteristically higher in our study than the previous studies in the literature. In addition, out of 85 Staphylococcus aureus isolates, 26 isolates showed sensitivity   to all antibiotics.Conclusions: From the present study we conclude that though the Staphylococcus aureus is usually having multidrug resistance pattern. So regular antimicrobial susceptibility surveillance is essential for area‐wise monitoring of the resistance patterns. This will be beneficial to preserve the effectiveness of antibiotics and for better patient management.


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