| Objective:Objective to collect the epidemiological characteristics,drug resistance and serotype distribution of Streptococcus pneumoniae among hospitalized patients in Yulin area,analyze the epidemic factors of sp infection,understand the drug resistance forms of SP,and evaluate the coverage of SP vaccine.Objective to improve the clinical diagnosis and treatment ability of SP disease,and to explore the effective measures to control its prevalence and reduce mortality.It can also provide a new basis for the national research and development of SP vaccine,help clinical rational use of antibiotics,improve the survival rate of patients,and reduce the economic burden of society and patients.Methods:(1)The clinical data of SP isolated from the samples of patients in our hospital from January 2015 to December 2019 were collected.The gender,age,Department distribution,onset season,hospital infection and other information of patients with sp infection were statistically analyzed,and the epidemic characteristics of patients with sp infection were studied and analyzed.(2)150 strains of SP were collected for drug sensitivity test.The drug sensitivity test was mainly performed by broth dilution method.The penicillin results were checked by E-test method.The antibiotic resistance of SP strains was analyzed,and the drug resistance patterns and changes were summarized.(3)The DNA of SP strain was extracted,and the expression of pbp2B,ermB and tetM were detected by PCR.(4)The serum distribution of 150 SP strains was studied by the internationally recognized gold standard "capsule swelling" test,and the results of the test were verified by PCR.Results:1.The epidemic characteristics of SP:respiratory tract specimens were the main type of SP infection in Yulin area,accounting for 91.6%,and the isolation rate of SP strains in sterile body fluid was 7.8%.There were significant differences in the separation rate of SP in different seasons(p<0.001),and the highest separation rate was in spring(30.6%).The majority of SP infection was in children under 5 years old(65.1%),followed by the elderly over 60 years old(18.3%).The majority of SP infection was male(68.8%)and female(31.2%).The Department with the highest SP separation rate was pediatrics department,and the separation rate was 64.9%,followed by ICU,respiratory department and neurology department.SP infection was mainly in community,accounting for 94.6%.The change of drug sensitivity of SP in recent 5 years showed that the sensitivity rate of vancomycin and linezolid was 100%,that is,there was no drug-resistant strain.The drug resistance rate of erythromycin was as high as 97.0%,tetracycline was more than 93.0%,the drug resistance rate of compound sulfamethoxazole was about 70.0%,and the drug resistance rate of quinolones was lower than 2.0%.The drug sensitivity data in 2019 showed that the resistance rate to penicillin,ceftriaxone,cefotaxime,amoxicillin and other beta lactam antibiotics was lower than that in the previous four years.2.SP resistance study:150 SP strains were arranged according to the drug resistance rate,and they could be divided into three echelons.Among them,the high resistance antibiotics were erythromycin,tetracycline and compound xinnuomine,and the drug resistance rate was 94.67%,92.67%and 64.68%,respectively.The drug resistance rate of the three generations cephalosporin was 30.0%and 28.67%respectively.The highly sensitive antimicrobial agents were levofloxacin,moxifloxacin and penicillin,and the insensitive rates were 2.66%,2.0%and 2.0%respectively.No resistant strains were found in vancomycin,linazolamide and etapenem.The multiple drug resistance SP accounted for 62.7%(94/150),and the drug resistance pattern was up to dozens of,among which,the drug resistance combination of tetracycline/erythromycin/compound Xinnuoming was the main,and 50 strains accounted for 33.3%.The SP strains which were resistant to erythromycin and tetracycline were 87.0%.The drug resistance genes of erythromycin were mainly ermB(98.0%).The main resistance genes of tetracycline were tetM(98.7%).There were 144 SP strains carrying both ermB and tetM genes,accounting for 96.0%.3.SP resistance study:150 SP strains were divided into three echelons according to the drug resistance rate.Among them,erythromycin,tetracycline and sulfamethoxazole were highly resistant,and the drug resistance rates were 94.67%,94.0%and 79.44%respectively.The drug resistance rates of cefotaxime and ceftriaxone were 24.00%and 24.01%respectively.The highly sensitive antibiotics were levofloxacin,moxifloxacin and penicillin,and the insensitivity rates were 2.66%,2.0%and 2.0%respectively.No resistant strains were found to vancomycin,linezolid and ertapenem.62.7%(94/150),and there were dozens of drug resistance patterns,among which 50 strains(33.3%)were mainly resistant to tetracycline/erythromycin/cotrimoxazole.About 87.0%of SP strains were resistant to erythromycin and tetracycline.ErmB was the main resistance gene of erythromycin,accounting for 98.0%.TetM was the main tetracycline resistance gene,accounting for 98.7%.There were 144 SP strains carrying both ermB and tetM genes,accounting for 96.0%.Serotype distribution of SP strains:the golden standard of serotyping-"capsular swelling" method was used to classify 150 SP strains,and 19 serotypes were successfully identified.The serotypes with higher detection rate were 19F(33.3%),6B(15.3%),15A(8.7%),23F(8.7%)and 3(7.3%).Among them,16F and 24F serotypes were not included in the vaccine coverage.Fourteen serotypes/groups were successfully identified by PCR.The most common serotypes/groups were 6A/B,19F,19A,15A and 23F.Among them,15B,24F and 4 serotypes were not successfully identified.The most common serotypes of non-invasive SP were 19F(43 strains,32.8%),6B(21 strains,16.0%),15A(11 strains,8.4%).The most common serotypes of invasive SP were 19F(7 strains,36.8%),6B(2 strains,10.5%),23F(2 strains,10.5%).The distribution of SP serotype in all age groups was statistically significant(p<0.05).There was no significant difference in the distribution of SP serotype between invasive and non-invasive specimens(p>0.05).The common serotypes of non multidrug resistant SP were 15A and 3,and the common serotypes of multidrug resistant SP were 19F and 6B.Non sensitivity analysis of the top 6 serotypes and conventional antibiotics:there were significant differences in drug resistance between different serotypes and antibiotics,and the main statistical differences were shown in chloramphenicol(p=0.002),compound sulfamethoxazole(p<0.001),cefotaxime(p<0.001)and ceftriaxone(p<0.001).In the whole population,the coverage rates of PCV7,PCV10,PCV13 and PPV23 were 36.8%,42.1%,57.9%and 62.2%,respectively.PCV13 vaccine can cover 53.3%of the serotypes of children under 6 years old,and PPV23 vaccine can cover 58.8%of the serotypes of people over 2 years old.In invasive specimens,PCV13 vaccine could cover 77.8%serotypes and PPV23 vaccine could cover 66.7%serotypes.Conclusion:1.From 2015 to 2019,respiratory tract specimens were the main type of SP infection,accounting for 91.6%,and the detection rate of invasive SP was 7.8%.Age and season are two important factors of SP infection,and spring is the most common season.Most of the children were younger than 5 years old.2.Among the antibiotics resistant to SP,erythromycin and tetracycline were the main antibiotics,and the drug resistance was more than 90.0%.Among them,62.7%showed multiple drug resistance,and the combination of erythromycin/tetracycline/cotrimoxazole was not sensitive to the drug resistance.There were two kinds of resistance genes detected by SP,ermB and tetM,and the SP containing these two genes was as high as 96.0%.It is suggested that the situation of multidrug resistance is serious in SP isolated from inpatients in Yulin.However,the sensitivity rate of SP to penicillin was 98.0%,which has important guiding value for clinical rational application and selection of antibiotics.3.The main prevalent serotypes of SP in Yulin were 19F,6B,15A,23F and 3.The distribution of serotypes varied with age,source,season and drug resistance pattern.In the whole population,PPV23 polysaccharide vaccine can cover more serotypes.However,for patients with invasive sp infection,PCV13 conjugate vaccine has a wider coverage than PPV23 polysaccharide vaccine. |
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