Gram Stain and Molecular Method for the Diagnosis of Bacterial Pneumonia.
Byline: Xu-Guang. Guo, Qing-Feng. Liu
To the Editor: We read an interesting paper entitled, “A Pilot Study of Quantitative Loop-mediated Isothermal Amplification-guided Target Therapies for Hospital-acquired Pneumonia” published in Chinese Medical Journal recently.[sup]
The authors did a great work to assess the method called quantitative loop-mediated isothermal amplification (qLAMP) as a new implement for steering of the antibiotic decision-making in hospital-acquired pneumonia and prove that qLAMP is a more promising method for detection of pathogens in an early, rapid, sensitive, and specific manner than traditional culture method.
Sputum collection is a complex process. Patients were instructed to expectorate sputum in a sterile sputum cup. The specimen was then transported to the bacteriology laboratory for Gram's stain and possible inoculation to the media. Only sputum samples with <10 squamous epithelial cells per low power field (LPF) and more than 25 leucocytes or polymorphonuclear cells (PMN) per LPF were accepted for Gram stain and culture.[sup] Some studies indicated that a specimen containing <25 PMN/LPF is likewise considered adequate or suitable in the presence of neutropenic state. Moreover, only sputum containing >25 leukocyte per LPF were cultured unless the patient is neutropenic. However, the included criteria of sputum specimen for microscopic examination were not described in this study.[sup]
LAMP is a relatively new DNA amplification technique,[sup], which due to its simplicity and low cost could provide major advantages. It has become the most valuable technology for clinical microbiology diagnosis in recent years.[sup] It should be noted that what should be paid attention to that interpretable experimental data of LAMP for sputum must combine with Gram's stain in clinical, otherwise, it probably mislead the doctor.
Financial support and sponsorship
This study was supported by the grant from the Medical and Health Science and Technology Projects of Guangzhou (No. 20151A011083).
Conflicts of interest
There are no conflicts of interest.
1. Wang F, Li R, Shang Y, Wang C, Wang GQ, Zhou DX, et al. A pilot study of quantitative loop-mediated isothermal amplification-guided target therapies for hospital-acquired pneumonia. Chin Med J 2016;129:181-6. doi: 10.4103/0366-6999.173484.
2. Wang Q, Zhou Y, Li S, Zhuo C, Xu S, Huang L, et al. Real-time fluorescence loop mediated isothermal amplification for the detection of Acinetobacter baumannii . PLoS One 2013;8:e66406. doi: 10.1371/journal.pone.0066406.
3. Nagamine K, Hase T, Notomi T. Accelerated reaction by loop-mediated isothermal amplification using loop primers. Mol Cell Probes 2002;16:223-9. doi: 10.1006/mcpr.2002.0415.
4. Nagamine K, Watanabe K, Ohtsuka K, Hase T, Notomi T. Loop-mediated isothermal amplification reaction using a nondenatured template. Clin Chem 2001;47:1742-3.
5. Xia Y, Guo XG, Zhou S. Rapid detection of Streptococcus pneumoniae by real-time fluorescence loop-mediated isothermal amplification. J Thorac Dis 2014;6:1193-9. doi: 10.3978/j.issn. 2072-1439.2014.07.29.
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|Author:||Guo, Xu-Guang; Liu, Qing-Feng|
|Publication:||Chinese Medical Journal|
|Article Type:||Letter to the editor|
|Date:||Aug 5, 2016|
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