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Rapid detection of Acinetobacter baumannii and molecular epidemiology of carbapenem-resistant A. baumannii in two comprehensive hospitals of Beijing, China.

Li P, Niu W, Li H, Lei H, Liu W, Zhao X, Guo L, Zou D, Yuan X, Liu H, Yuan J, Bai C - Front Microbiol (2015)

Bottom Line: The detection limit was 50 pg/μl, which was about 10-fold greater than that of PCR.In conclusion, the LAMP method developed for detecting A. baumannii was faster and simpler than conventional PCR and has great potential for both point-of-care testing and basic research.We further demonstrated a high distribution of class D carbapenemase-encoding genes, mainly OXA-23, which presents an emerging threat in hospitals in China.

View Article: PubMed Central - PubMed

Affiliation: Department of Respiratory and Critical Care Diseases, 307th Hospital of Chinese People's Liberation Army Beijing, China.

ABSTRACT
Acinetobacter baumannii is an important opportunistic pathogen associated with a variety of nosocomial infections. A rapid and sensitive molecular detection in clinical isolates is quite needed for the appropriate therapy and outbreak control of A. baumannii. Group 2 carbapenems have been considered the agents of choice for the treatment of multiple drug-resistant A. baumannii. But the prevalence of carbapenem-resistant A. baumannii (CRAB) has been steadily increasing in recent years. Here, we developed a loop-mediated isothermal amplification (LAMP) assay for the rapid detection of A. baumannii in clinical samples by using high-specificity primers of the bla OXA-51 gene. Then we investigated the OXA-carbapenemases molecular epidemiology of A. baumannii isolates in two comprehensive hospitals in Beijing. The results showed that the LAMP assay could detect target DNA within 60 min at 65°C. The detection limit was 50 pg/μl, which was about 10-fold greater than that of PCR. Furthermore, this method could distinguish A. baumannii from the homologous A. nosocomialis and A. pittii. A total of 228 positive isolates were identified by this LAMP-based method for A. baumannii from 335 intensive care unit patients with clinically suspected multi-resistant infections in two hospitals in Beijing. The rates of CRAB are on the rise and are slowly becoming a routine phenotype for A. baumannii. Among the CRABs, 92.3% harbored both the bla OXA-23 and bla OXA-51 genes. Thirty-three pulsotypes were identified by pulsed-field gel electrophoresis, and the majority belonged to clone C. In conclusion, the LAMP method developed for detecting A. baumannii was faster and simpler than conventional PCR and has great potential for both point-of-care testing and basic research. We further demonstrated a high distribution of class D carbapenemase-encoding genes, mainly OXA-23, which presents an emerging threat in hospitals in China.

No MeSH data available.


Related in: MedlinePlus

Specificity of the LAMP reactions in detecting the blaOXA-51-like gene. Turbidity was monitored using a Loopamp real-time turbidimeter by measuring the absorbance at 650 nm every 6 s. Amplification was performed at 65°C for 60 min.
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Figure 3: Specificity of the LAMP reactions in detecting the blaOXA-51-like gene. Turbidity was monitored using a Loopamp real-time turbidimeter by measuring the absorbance at 650 nm every 6 s. Amplification was performed at 65°C for 60 min.

Mentions: To evaluate the specificity of LAMP detection for A. baumannii, genomic DNA was extracted from 2 A. baumannii strains, as well as other 7 Acinetobacter species (10 strains) and 22 non-A. baumannii reference strains, and tested using real-time turbidity or visual detection of color changes as readouts. Genomic A. baumannii DNA (ATCC 22933) and distilled water were used as positive and negative controls, respectively. As shown in Figure 3, both methods of analysis positively identified the A. baumannii isolates. All other strains (as well as the blank control) tested negatively, indicating that the LAMP assay was specific for A. baumannii. Interestingly, the LAMP assay could differentiate A. baumannii from other Acinetobacter species.


Rapid detection of Acinetobacter baumannii and molecular epidemiology of carbapenem-resistant A. baumannii in two comprehensive hospitals of Beijing, China.

Li P, Niu W, Li H, Lei H, Liu W, Zhao X, Guo L, Zou D, Yuan X, Liu H, Yuan J, Bai C - Front Microbiol (2015)

Specificity of the LAMP reactions in detecting the blaOXA-51-like gene. Turbidity was monitored using a Loopamp real-time turbidimeter by measuring the absorbance at 650 nm every 6 s. Amplification was performed at 65°C for 60 min.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4585070&req=5

Figure 3: Specificity of the LAMP reactions in detecting the blaOXA-51-like gene. Turbidity was monitored using a Loopamp real-time turbidimeter by measuring the absorbance at 650 nm every 6 s. Amplification was performed at 65°C for 60 min.
Mentions: To evaluate the specificity of LAMP detection for A. baumannii, genomic DNA was extracted from 2 A. baumannii strains, as well as other 7 Acinetobacter species (10 strains) and 22 non-A. baumannii reference strains, and tested using real-time turbidity or visual detection of color changes as readouts. Genomic A. baumannii DNA (ATCC 22933) and distilled water were used as positive and negative controls, respectively. As shown in Figure 3, both methods of analysis positively identified the A. baumannii isolates. All other strains (as well as the blank control) tested negatively, indicating that the LAMP assay was specific for A. baumannii. Interestingly, the LAMP assay could differentiate A. baumannii from other Acinetobacter species.

Bottom Line: The detection limit was 50 pg/μl, which was about 10-fold greater than that of PCR.In conclusion, the LAMP method developed for detecting A. baumannii was faster and simpler than conventional PCR and has great potential for both point-of-care testing and basic research.We further demonstrated a high distribution of class D carbapenemase-encoding genes, mainly OXA-23, which presents an emerging threat in hospitals in China.

View Article: PubMed Central - PubMed

Affiliation: Department of Respiratory and Critical Care Diseases, 307th Hospital of Chinese People's Liberation Army Beijing, China.

ABSTRACT
Acinetobacter baumannii is an important opportunistic pathogen associated with a variety of nosocomial infections. A rapid and sensitive molecular detection in clinical isolates is quite needed for the appropriate therapy and outbreak control of A. baumannii. Group 2 carbapenems have been considered the agents of choice for the treatment of multiple drug-resistant A. baumannii. But the prevalence of carbapenem-resistant A. baumannii (CRAB) has been steadily increasing in recent years. Here, we developed a loop-mediated isothermal amplification (LAMP) assay for the rapid detection of A. baumannii in clinical samples by using high-specificity primers of the bla OXA-51 gene. Then we investigated the OXA-carbapenemases molecular epidemiology of A. baumannii isolates in two comprehensive hospitals in Beijing. The results showed that the LAMP assay could detect target DNA within 60 min at 65°C. The detection limit was 50 pg/μl, which was about 10-fold greater than that of PCR. Furthermore, this method could distinguish A. baumannii from the homologous A. nosocomialis and A. pittii. A total of 228 positive isolates were identified by this LAMP-based method for A. baumannii from 335 intensive care unit patients with clinically suspected multi-resistant infections in two hospitals in Beijing. The rates of CRAB are on the rise and are slowly becoming a routine phenotype for A. baumannii. Among the CRABs, 92.3% harbored both the bla OXA-23 and bla OXA-51 genes. Thirty-three pulsotypes were identified by pulsed-field gel electrophoresis, and the majority belonged to clone C. In conclusion, the LAMP method developed for detecting A. baumannii was faster and simpler than conventional PCR and has great potential for both point-of-care testing and basic research. We further demonstrated a high distribution of class D carbapenemase-encoding genes, mainly OXA-23, which presents an emerging threat in hospitals in China.

No MeSH data available.


Related in: MedlinePlus