Changes And Significance Of CRP/PCT Ratio In Adult Mycoplasma Pneumoniae Pneumonia And Bacterial Pneumonia

Background Community acquired pneumonia(CAP)has always been one of the diseases with high morbidity and mortality worldwide.Early diagnosis of CAP and clear etiology have a positive impact on the therapeutic effect and prognosis of patients.Mycoplasma pneumoniae pneumonia(MPP)is a special type of CAP,frequently occurring in children groups.Recent studies have shown that the proportion of MPP in adult with CAP is gradually increasing.Mycoplasma pneumoniae is an atypical pathogen,and its anti-infection treatment strategy is different from that of typical bacterial pneumonia.Therefore,early screening of MPP from CAP is conducive to the implementation of precise treatment and the prognosis of patients.This paper discusses the differences of neutrophil count,neutrophil percentage,procalcitonin(PCT)、 C-reactive protein(CRP)and CRP/PCT ratio,clinical manifestations and imaging features between MPP and bacterial pneumonia,and its differential significance was further analyzed to improve the early screening ability of MPP.Objective Analyze neutrophil count、neutrophil percentage、CRP、PCT、CRP/PCT ratio and clinical features 、 imaging features in adults with MPP and bacterial pneumonia,to enhance the discrimination patients with mycoplasma pneumonia from others with bacterial pneumonia.Methods From August 2018 to June 2020,a retrospective study was conducted among 66 adult patients with positive results of Mycoplasma antibody Ig M test、90adult patients with bacterial pneumonia who were admitted to the second affiliated hospital of Anhui Medical University was selected,compared CRP、PCT and other examination indexes and clinical characteristics 、 imaging manifestations in the two groups of patients.The value of CRP、PCT and CRP/PCT ratio in predicting MPP patients was analyzed by using receiver operating characteristic(ROC)curve.Results Patients diagnosed with MPP were remarkably younger than those with bacterial pneumonia.The incidence of expectoration and chest distress in bacterial pneumonia group was higher than that in MPP group,while the proportion of patients with symptoms of dry cough and myalgia was lower than that in MPP group.Compared with the chest CT in bacterial pneumonia group,MPP group had less invasive consolidation and pleural effusion,but more lesions in the center of the lobules and mass-like shadow.Laboratory examination:the levels of PCT、CRP、white blood cell count and neutrophil count in bacterial pneumonia group were higher than those in MPP group and the CRP/PCT ratio was lower than that in MPP group.All the differences above were statistically significant(P<0.05).The area-under-curve(AUC)values of CRP、PCT and CRP/PCT ratio in predicting patients with MPP were0.64、0.86 and 0.89 respectively.The sensitivities of CRP、PCT and CRP/PCT ratio in predicting patients with MPP were 89.4%、100% and 87.9%,respectively.And the specificities were 43.3%、55.6% and 83.3%,respectively.Conclusion The levels of CRP、PCT、CRP/PCT ratio in MPP group and bacterial pneumonia group were significantly different.The above examination indexes combined with clinical characteristics and imaging features could play an important role in discriminating MPP from bacterial pneumonia.