Background
Acinetobacter baumannii (A. baumannii) is an important nosocomial pathogen in hospital-acquired infections, and the resistance to carbapenems has been observed increasingly worldwide. Oxacillinase produced by blaOXA-23 is one of the predominant carbapenem resistance mechanisms in A. baumannii, which is highly prevalent worldwide, especially in China. The rapid identification of blaOXA-23 may give a valuable hint for the administration of directed antimicrobial therapy.
Method
In this study, we aimed to develop a LAMP-based detection for the blaOXA-23 gene; clinical samples of A. baumannii were used to determine the sensitivity and specificity of this method compared to phenotypic antimicrobial susceptibility testing and traditional PCR method. MLST was performed to investigate the epidemiology of A. baumannii bacterial population.
Results
Compared to the antimicrobial susceptibility testing, the sensitivity and specificity of LAMP in detecting blaOXA-23 was 88.4% and 97.7%, respectively. However, the LAMP method was found to be much simpler and the result could be available in a shorter period (within 60 minutes) when compared to conventional PCR and phenotypic susceptibility testing. The 113 isolates could be clustered into 30 sequence types (STs), and majority (83/113) of these strains belong to clonal complex 92 (CC92), which is also the dominant CC in the China.
Conclusion
The LAMP-based method detected blaOXA-23 in a much simpler way, by which could provide timelier results for differentiating the carbapenem-resistant Acinetobacter baumannii than conventional methods. Consequently, blaOXA-23 may potentially serving as surrogate marker for the presence of CRAB in patients with serious infections in clinic.

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Posted 13 Jun, 2019
Posted 13 Jun, 2019
Background
Acinetobacter baumannii (A. baumannii) is an important nosocomial pathogen in hospital-acquired infections, and the resistance to carbapenems has been observed increasingly worldwide. Oxacillinase produced by blaOXA-23 is one of the predominant carbapenem resistance mechanisms in A. baumannii, which is highly prevalent worldwide, especially in China. The rapid identification of blaOXA-23 may give a valuable hint for the administration of directed antimicrobial therapy.
Method
In this study, we aimed to develop a LAMP-based detection for the blaOXA-23 gene; clinical samples of A. baumannii were used to determine the sensitivity and specificity of this method compared to phenotypic antimicrobial susceptibility testing and traditional PCR method. MLST was performed to investigate the epidemiology of A. baumannii bacterial population.
Results
Compared to the antimicrobial susceptibility testing, the sensitivity and specificity of LAMP in detecting blaOXA-23 was 88.4% and 97.7%, respectively. However, the LAMP method was found to be much simpler and the result could be available in a shorter period (within 60 minutes) when compared to conventional PCR and phenotypic susceptibility testing. The 113 isolates could be clustered into 30 sequence types (STs), and majority (83/113) of these strains belong to clonal complex 92 (CC92), which is also the dominant CC in the China.
Conclusion
The LAMP-based method detected blaOXA-23 in a much simpler way, by which could provide timelier results for differentiating the carbapenem-resistant Acinetobacter baumannii than conventional methods. Consequently, blaOXA-23 may potentially serving as surrogate marker for the presence of CRAB in patients with serious infections in clinic.

Figure 1

Figure 2

Figure 3

Figure 4
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