Methods
Children under the age of 18 years old admitted to Tuen Mun Hospital, a local regional hospital serving a population of over one million in the northwest region of Hong Kong, with a diagnosis of CAP and subsequently tested positive for Mycoplasma PCR isolated from nasopharyngeal aspirates or sputum, gastric lavage samples in the period of March 2013 to August 2013 were retrospectively studied.
The diagnosis of pneumonia was based on fever, acute respiratory symptoms (tachypnoea, chest retractions, abnormal findings on ausculation) or both, with evidence of parenchymal infiltrates on chest radiography.
Based on the direct DNA sequencing of the domain V of the 23S rRNA gene, mutations associated with macrolide resistance were identified and divided the patients into MRMP and MSMP groups. All patients screened positive had a mutation at the position 2063 of the gene. Their medical records were reviewed and demographic data such as age and sex, previous use of antibiotics prior to admission and travel history 2 weeks prior to admission were recorded with the investigator blinded to their respective MSMP or MRMP status.
Clinical parameters including cough, shortness of breath, respiratory rate, rash, and oxygen supplementation required were compared.
Laboratory findings including white blood cell count (absolute neutrophil and lymphocyte count) and C-reactive protein levels (CRP), erythrocyte sediment rate (ESR), alanine aminotransferase (ALT), cold agglutinin levels were compared between the two groups. Radiological findings on chest radiographs were also analyzed. A total of 74 patients were included in the subgroup analysis performed with characteristics within the episode of admission such as total duration of fever and time to defervescence (defined as core body temperature less than 38.5°C for 3 consecutive readings with no recurrence of fever within 24 hours without the use of antipyretics).
All statistical analysis was performed using the SPSS software, version 21. Categorical variables were assessed by two-tailed Fisher’s exact test and chi-square test, Mann–Whitney U-test was used for continuous variables. ROC curves and area under curve was constructed to look at clinically predictive factors for MRMP. P value <0.05 was considered statistically significant.
Approval was obtained with IRB prior to conducting this study.