Evaluation of antibiotic susceptibility test results: how guilty a laboratory could be?
Abstract Background The selection of an appropriate antimicrobial is a challenging task for clinicians. The Kirby-Bauer disk diffusion method is one of the most widely practiced antimicrobial susceptibility tests (AST). It is affected by many factors among which are the media used. Mueller-Hinton ag...
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| Format: | Article |
| Language: | English |
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SpringerOpen
2019-01-01
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| Series: | Journal of the Egyptian Public Health Association |
| Subjects: | |
| Online Access: | http://link.springer.com/article/10.1186/s42506-018-0006-1 |
| _version_ | 1828811340304613376 |
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| author | Mohamed S. M. Nassar Walaa A. Hazzah Wafaa M. K. Bakr |
| author_facet | Mohamed S. M. Nassar Walaa A. Hazzah Wafaa M. K. Bakr |
| author_sort | Mohamed S. M. Nassar |
| collection | DOAJ |
| description | Abstract Background The selection of an appropriate antimicrobial is a challenging task for clinicians. The Kirby-Bauer disk diffusion method is one of the most widely practiced antimicrobial susceptibility tests (AST). It is affected by many factors among which are the media used. Mueller-Hinton agar (MHA) is the standard medium recommended in guidelines. However, these guidelines are not strictly adhered to in some developing countries. Objectives Validation of AST results on nutrient agar (NA) medium used as a substitute for MHA by some microbiology laboratories in Alexandria, Egypt. Methods A total of 149 clinical bacterial isolates and 3 reference strains: Staphylococcus aureus (S. aureus) ATCC® 25923, Escherichia coli (E. coli) ATCC®25922, and Pseudomonas aeruginosa (P. aeruginosa) ATCC®27853 were comparatively challenged to antibiotics employing MHA and NA. Results All antibiotics-reference bacterial strain challenges on NA compared to MHA were unacceptable (> 3 out of limit zones in 30 consecutive days). Considering clinical isolates, the frequency of very major, major, and minor errors on NA was highest in the case of P. aeruginosa (8.98%, 4.08%, and 14.7% respectively) followed by S. aureus (7.6%, 6%, and 8.8% respectively). On the other hand, the least frequency of errors was in the case of Enterobacteriaceae (0%, 0.4%, and 3.2% respectively). Conclusions and recommendations Using NA in AST resulted in multiple errors and the high discrepancy in results compared to MHA making it unreliable for susceptibility testing. MHA should not be replaced by NA in AST. Following guidelines and QC measures for AST must be neither bypassed nor underestimated. |
| first_indexed | 2024-12-12T09:25:27Z |
| format | Article |
| id | doaj.art-06112a9038c54e45bbee98046e9fc673 |
| institution | Directory Open Access Journal |
| issn | 2090-262X |
| language | English |
| last_indexed | 2024-12-12T09:25:27Z |
| publishDate | 2019-01-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Journal of the Egyptian Public Health Association |
| spelling | doaj.art-06112a9038c54e45bbee98046e9fc6732022-12-22T00:29:02ZengSpringerOpenJournal of the Egyptian Public Health Association2090-262X2019-01-019411510.1186/s42506-018-0006-1Evaluation of antibiotic susceptibility test results: how guilty a laboratory could be?Mohamed S. M. Nassar0Walaa A. Hazzah1Wafaa M. K. Bakr2Department of Microbiology, High Institute of Public Health, Alexandria UniversityDepartment of Microbiology, High Institute of Public Health, Alexandria UniversityDepartment of Microbiology, High Institute of Public Health, Alexandria UniversityAbstract Background The selection of an appropriate antimicrobial is a challenging task for clinicians. The Kirby-Bauer disk diffusion method is one of the most widely practiced antimicrobial susceptibility tests (AST). It is affected by many factors among which are the media used. Mueller-Hinton agar (MHA) is the standard medium recommended in guidelines. However, these guidelines are not strictly adhered to in some developing countries. Objectives Validation of AST results on nutrient agar (NA) medium used as a substitute for MHA by some microbiology laboratories in Alexandria, Egypt. Methods A total of 149 clinical bacterial isolates and 3 reference strains: Staphylococcus aureus (S. aureus) ATCC® 25923, Escherichia coli (E. coli) ATCC®25922, and Pseudomonas aeruginosa (P. aeruginosa) ATCC®27853 were comparatively challenged to antibiotics employing MHA and NA. Results All antibiotics-reference bacterial strain challenges on NA compared to MHA were unacceptable (> 3 out of limit zones in 30 consecutive days). Considering clinical isolates, the frequency of very major, major, and minor errors on NA was highest in the case of P. aeruginosa (8.98%, 4.08%, and 14.7% respectively) followed by S. aureus (7.6%, 6%, and 8.8% respectively). On the other hand, the least frequency of errors was in the case of Enterobacteriaceae (0%, 0.4%, and 3.2% respectively). Conclusions and recommendations Using NA in AST resulted in multiple errors and the high discrepancy in results compared to MHA making it unreliable for susceptibility testing. MHA should not be replaced by NA in AST. Following guidelines and QC measures for AST must be neither bypassed nor underestimated.http://link.springer.com/article/10.1186/s42506-018-0006-1CLSIMueller-Hinton agarInhibition zonesDisk diffusion methodQuality control |
| spellingShingle | Mohamed S. M. Nassar Walaa A. Hazzah Wafaa M. K. Bakr Evaluation of antibiotic susceptibility test results: how guilty a laboratory could be? Journal of the Egyptian Public Health Association CLSI Mueller-Hinton agar Inhibition zones Disk diffusion method Quality control |
| title | Evaluation of antibiotic susceptibility test results: how guilty a laboratory could be? |
| title_full | Evaluation of antibiotic susceptibility test results: how guilty a laboratory could be? |
| title_fullStr | Evaluation of antibiotic susceptibility test results: how guilty a laboratory could be? |
| title_full_unstemmed | Evaluation of antibiotic susceptibility test results: how guilty a laboratory could be? |
| title_short | Evaluation of antibiotic susceptibility test results: how guilty a laboratory could be? |
| title_sort | evaluation of antibiotic susceptibility test results how guilty a laboratory could be |
| topic | CLSI Mueller-Hinton agar Inhibition zones Disk diffusion method Quality control |
| url | http://link.springer.com/article/10.1186/s42506-018-0006-1 |
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