mycoplasma pneumoniae ( mp ) is one of the most common respiratory tract pathogens in community - acquired pneumonia ( cap ) patients . as one of the smallest bacterial organisms ,
mp is recognized as a capable of existence in both extracellular and intracellular environments which might facilitate the establishment of latent or chronic states . by the first proven link between an infectious agent and cancer
came in the 1960s with the discovery of epstein  barr virus in burkitt s lymphoma tissue , it is likely that organisms which can persist at an intracellular level will have the greatest potential to influence oncogenesis . in recent years
, the association between malignant cell transformation and infection with mycoplasma has been identified in vitro .
nevertheless , there have been very few reports focusing on the cell pathology in mp infection in vivo .
therefore , the aim of this study was to identify the degree of cellular dysplasia in respiratory epithelium from mpp in comparison to other cap infections caused by typical pathogens .
all patients were over 18 years old of age with cap , who underwent both chest computed tomography ( ct ) and bronchoscopy in two hospitals between april 2013 and august 2015 .
the acute phase serum samples were tested for igm antibodies to mp by enzyme - linked immunosorbent assays test .
the definitive diagnosis of mp infection was confirmed by a positive balf result using quantitative loop - mediated isothermal amplification ( qlampp ) assays targeting for the p1 operon sequences using the universal kit for bacterial dna extraction ( capitalbio corporation , p.r . china ) as described elsewhere .
screening for eight common respiratory bacterial pathogens in balf was performed using qlamp assay as described elsewhere .
nine respiratory viruses in balf were detected using ftd respiratory pathogens 21 plus multiplex real - time polymerase chain reaction kit ( fast - track diagnostics , junglinster , luxembourg ) .
cap caused by bacterial pathogens and demonstrating a negative qlamp assay for mp gene categorized the non - mp ( typical cap ) infection group ( t - cap group ) .
the patients with suspected malignant lesions seen under direct vision on bronchoscopy or on ct scan , or patients with cap caused by respiratory viruses and mixed infection were excluded .
the cast - off epithelial cells were obtained via conventional bronchoscopy by brushing the infectious airway mucosa 23 times .
the samples were analyzed as a cell smear in the fully automatic liquid - based cytology instrument ( thinpreptm2000 , hologic , inc .
two senior pulmonary cytopathologists evaluated the specimen blindly under light microscopy by hematoxylin and eosin staining .
cell morphology was graded for cellular dysplasia according to the cellular and nuclei size , nuclear - cytoplasmic ( n : c ) ratio , the shape and halves of the nucleus , and chromatin pattern as previously established .
statistical analysis was performed using the spss version 16.0 for windows ( spss inc . , ibm , usa ) .
categorical variables and continuous variables were reported as percentages and as the mean  standard deviation , respectively .
chi - square test and independent - samples student s t - test were employed .
a total of 15 patients with mpp were included in mpp group and 17 with typical cap patients caused by other pathogens ( t - cap group ) . in the mpp group ,
nine patients were diagnosed based on qlamp assay alone and six patients based on serology alone .
a positive bacterium was detected in only 12% ( 2/17 ) of the t - cap group patients on qlamp assay , one streptococcus pneumoniae , and one klebsiella pneumoniae .
about 17 of 32 patients had received antibiotic therapy ( > 3 days duration ) prior to admission .
the patients in mpp group were younger , more likely to be female , and more likely to have a lower c - reactive protein level than those of the t - cap group ( 43.33  16.09 years vs. 57.29  15.89 years , 60% vs. 17.6% , and 55.73  44.63 mg /
l vs. 115.95  73.90 mg / l , respectively ) . both epithelial cells and inflammatory cells were found in the brushing samples .
a representative high - power photomicrograph of epithelial cellular dysplasia is shown in figure 1 , compared to normal epithelial cells in figure 2 .
the identification of total cellular and nuclear dysplasia was significantly higher in the mpp group [ table 1 ] .
the respiratory epithelial cells of dysplasia ( arrow ) varied markedly in size and shape , nuclear pleomorphism with a significantly abnormal karyoplasmic ratio ( h and e stained smearing sample , 400 from a patient with mycoplasma pneumonia ) the heaped - up normal respiratory epithelial cells were shown ( h and e stained smearing sample , 400 from a patient with community - acquired pneumonia ) morphological finding of respiratory epithelial cells in patients with mycoplasma pneumonia and other pathogenic pneumonia
laboratory data have demonstrated the potential for some mycoplasma species to induce a karyotypic change and malignant transformation during prolonged or chronic tissue - culture infection in vitro .
preneoplastic changes in cultured cells may be reversed following eradication by appropriate antibiotic treatment . by a complex and specialized attachment organelle to attach to the respiratory epithelium with ease , mycoplasma is primarily considered a mucosal pathogen for parasitic existence . because it lacks a rigid cell wall , several mycoplasmal species have demonstrated the ability to fuse with and enter host cells which are not normally phagocytic , and the ability to survive , synthesize dna , and undergo cell replication in host cells in vitro . in contrast , the common bacteria such as streptococci are generally considered as extracellular pathogens because their polysaccharide capsule significantly attenuates their ability to invade the cytoplasm of respiratory epithelial cells , although occasional intracellular uptake may occur .
in addition , the intracellular damage from mycoplasmal enzymes and cytotoxins may be another cause to nuclear atypia . to our knowledge
, this is the first study to demonstrate a clear dyskaryotic change in airway epithelial cells in patients suffering from mp than that in patients suffered by other organisms in vivo . in this study , there was none of patients tested positive bacterial species for routine sputum culture , which was compatible with the findings partly caused by antimicrobial treatment before the collection of specimens as described recently . due to the application of antibiotics in the majority of candidates before admission and consequent effect on direct bacterial identification from delayed balf samples , we applied a method of genetic and immunological exclusion to categorize cap patients .
we found that many clinical differences between two groups were similar to those described in other studies .
the special biological characteristics and mechanisms of pathogenesis of mp may be reflected in the different cytopathological aspects of mpp .
this preliminary study identifies a potential ability of mp to evoke dyskaryotic changes in respiratory epithelium , which may imply an oncogenic potential of latent or chronic mp infection .
this study was supported by the national 12th five - year plan major scientific and technological program from the ministry of science and technology of china ( no .
daniel edward porter , director of department of orthopedics , first hospital of tsinghua university , for kindly helping the english version .
this study was supported by the national 12th five - year plan major scientific and technological program from the ministry of science and technology of china ( no .
daniel edward porter , director of department of orthopedics , first hospital of tsinghua university , for kindly helping the english version .
sca carried out the design of the work , conducted the study , performed the statistical analysis and prepared the draft and the final version of the manuscript .
 background : this study aimed to explore the cellular morphology of respiratory epithelium in mycoplasma pneumonia ( mpp ) patients.materials and methods : the cast - off cell morphological findings from bronchoscopic brushings in mpp and community - acquired pneumonia ( cap ) caused by typical pathogens were reviewed.results:compared with the cap group , cellular dysplasia in respiratory tract epithelial brushings was significantly greater in mpp patients ( p = 0.033).conclusion : unique biological characteristics and mechanisms of pathogenesis of mycoplasma pneumoniae ( mp ) may result in dyskaryotic changes in respiratory epithelium in adult mpp . 
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
CONCLUSIONS
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