Rapid Detection of Antibiotic Resistance in Gram-Negative Bacteria Through Assessment of Changes in Cellular Morphology.
Rapid antimicrobial susceptibility testing has the potential to improve patient outcomes and reduce healthcare-associated costs. In this study, a novel assay based on bacterial cell elongation after exposure to an antibiotic (ceftazidime) was evaluated for its ability to rapidly detect resistance in Gram-negative bacteria. The assay was used to detect resistance in a large collection of strains containing 320 clinical isolates of Acinetobacter baumannii, 171 clinical isolates of Klebsiella pneumoniae, and 212 clinical isolates of Pseudomonas aeruginosa, and the results were compared to those obtained using standard antimicrobial susceptibility testing methods. The assay identified ceftazidime-resistant strains with 100% sensitivity and 100% specificity for A. baumannii, 100% sensitivity and 97.2% specificity for K. pneumoniae, and with 82.3% sensitivity and 100% specificity for P. aeruginosa. Importantly, results were obtained in 1 hour 15 minutes from exponentially growing cultures. This study demonstrates that changes in cell length are highly correlated with phenotypic antibiotic susceptibility determined using standard susceptibility testing methods. This study therefore provides proof-of-concept that changes in cell morphology can be used as the basis for rapid detection of antibiotic resistance and provides the basis for the development of novel rapid diagnostics for the detection of antibiotic resistance.
1 Unidad de Genética, INIBIC-Complejo Hospitalario Universitario A Coruña , A Coruña, Spain .|2 Laboratorio de Genética, Centro Oncológico de Galicia , A Coruña, Spain .
Fátima
F
Otero
1 Unidad de Genética, INIBIC-Complejo Hospitalario Universitario A Coruña , A Coruña, Spain .|2 Laboratorio de Genética, Centro Oncológico de Galicia , A Coruña, Spain .
Rebeca
R
Santiso
1 Unidad de Genética, INIBIC-Complejo Hospitalario Universitario A Coruña , A Coruña, Spain .|2 Laboratorio de Genética, Centro Oncológico de Galicia , A Coruña, Spain .
Maria
M
Tamayo
1 Unidad de Genética, INIBIC-Complejo Hospitalario Universitario A Coruña , A Coruña, Spain .|2 Laboratorio de Genética, Centro Oncológico de Galicia , A Coruña, Spain .
José Luis
JL
Fernández
3 Servicio de Microbiología, INIBIC-Complejo Hospitalario Universitario A Coruña , A Coruña, Spain .
Germán
G
Bou
4 Clinical Unit of Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville (IBiS), University Hospitals Virgen del Rocío and Virgen Macarena, Seville, Spain .
José Antonio
JA
Lepe
4 Clinical Unit of Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville (IBiS), University Hospitals Virgen del Rocío and Virgen Macarena, Seville, Spain .
Michael J
MJ
McConnell
5 Unidad de Genética, Facultad de Biología, Universidad Autónoma de Madrid , Madrid, Spain .
Jaime
J
Gosálvez
4 Clinical Unit of Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville (IBiS), University Hospitals Virgen del Rocío and Virgen Macarena, Seville, Spain .
José Miguel
JM
Cisneros
D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D002442:Ceftazidime / Q000627:therapeutic use; D024881:Drug Resistance, Bacterial / Q000502:physiology*; D006090:Gram-Negative Bacteria / Q000166:cytology* / Q000187:drug effects* / Q000502:physiology; D016905:Gram-Negative Bacterial Infections / Q000188:drug therapy; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods
D000900:Anti-Bacterial Agents; D002442:Ceftazidime
antibiotic resistance; rapid diagnostics; susceptibility testing