ABSTRACT
Objective To screen and identify the aptamers of the recombinant transpeptidase domain of PBP2a(penicillin binding protein 2a ,PBP2a) .Methods By using the recombinant transpeptidase domain of PBP2a as the screening target ,oligonucle-otides which were capable of specifically binding to the protein were screened by a random oligonucleotide library through the stem -atic evolution of ligand by exponential enrichment (SELEX )technique .The ssDNA was cloned and sequenced ,and the secondary structure of aptamer clones was predicted with mfold program .Results After 11 cycles of the selection ,the aptamers which were capable of binding to PBP2a with high affinity have been selected .40 clones from the 8 and 10 cycles were selected randomly and se-quenced .The aptamers obtained had no obvious homology according to their sequences by the sequence alignments ,and the 40 aptamers were classified to three groups according to their secondary structures .The aptamer 13 was found to be specific for the target protein with the highest affinity .Conclusion Aptamers for the recombinant transpeptidase domain of PBP2a with high affili-ty and specificity were successfully screened by SELEX ,which lays a foundation for exploring new ways of diagnosis and treatment of MRSA infection .
ABSTRACT
Objective To explore the clinical manifestations and epidemiological profiles of hospitalized infants with Bordetella pertussis infection and to improve the knowledge for its early diagnosis and treatment.Methods Using a retrospective analysis method,the data of 142 hospitalized infants with Bordetella pertussis infection in Shenzhen Children's Hospital from 2011 to 2013 were collected,which was confirmed by a real-time polymerase chain reaction(PCR) of nasopharyngeal secretion.The SPSS 16.0 software was used for statistical analysis.Results Of the 142hospitalized infants with Bordetella pertussis infection,the ratio of male to female was 2.1∶ 1.0 (96/41 cases).Ninetythree (65.5％) cases were aged less than 3 months old,26 cases (18.3％) were 3-6 months old and 23 cases (16.2％) were 6-36 months old.One hundred and twenty-six (88.7％) patients were unvaccinated or incompletely vaccinated.The most common clinical manifestation was paroxysmal cough which accounts for 104/142 (73.2％) cases,and 6 cases of which had roaring(4.2％).Peripheral blood WBC level of 83 cases increased,and 75 (90.4％) cases were lymphocytosis.The positive rate of X-ray was 60.6％.Eighty-one cases were complicated with bacteria,respiratory virus or mycoplasma pneumonia infection.There were significant differences in symptom of fever and infection of respiratory tract pathogen among 3 groups.The symptom of fever in the group aged less than 3 months old group was significantly lower than the other 2 groups (x2 =11.45,P ＜ 0.01 ;x2 =34.56,P ＜ 0.01),and 6-36 months old group was significantly higher than the other 2 groups(x2 =7.590,P ＜ 0.01 ;x2 =6.928,P ＜ 0.01).Conclusions Bordetella pertussis is an important pathogen for the infants with persistent cough,especially in unvaccinated or incompletely vaccinated infants,but the clinical manifestation and signs of pertussis are atypical,which may lead to a misdiagnosis and delay proper treatment.As a rapid and sensitive method of detecting Bordetella pertussis,PCR may be used for early diagnosis.