Abstract: Objective To investigate the clinical distribution characteristics, drug resistance trends and the carrying of antiseptic resistance gene of Pseudomonas aeruginosa infection in children in Suzhou, in order to provide theoretical basis for the prevention and treatment of Pseudomonas aeruginosa infection in children. Methods The clinical distribution characteristics and drug resistance trends of Pseudomonas aeruginosa isolated from Children's Hospital of Soochow University from 2016 to 2021 were retrospectively analyzed. Forthermore, 101 strains of Pseudomonas aeruginosa were randomly selected to detect the expression of 9 antiseptic resistance genes (qacEΔ1-sul1, qacE, qacEΔ1, qacG, sugE(p), sugE©, emrE, ydgE, ydgF) by polymerase chain reaction. Results Pseudomonas aeruginosa in Soochow University Children's Hospital was mainly isolated from respiratory specimen (47.83%), pus (28.60%) and urine (11.72%); the main departments were intensive care unit(21.45%), general surgery department (15.71%) and respiratory department (12.31%). Patients were mainly aged from 1 month to 1 year old and older than 6 years old (34.31% and 25.38%). The top three drug resistance rates of Pseudomonas aeruginosa were imipenem (11.25%), aztreonam (9.26%) and meropenem (8.02%). Among the 853 strains of Pseudomonas aeruginosa, the drug-resistant strains were mainly from the intensive care unit (58/183), hematology department (33/91), neonatology department (31/96), and there were 57 strains of multi-drug-resistant strains with the detection rate of 6.68%. There were 98 strains (11.49%) of Carbapenem resistant Pseudomonas aeruginosa, and the annual detection rates were 22.06%, 8.40%, 3.60%, 5.67%, 9.85% and 17.20%, respectively. Among the 9 antiseptic resistance genes, the carrying rate of ydgF, sugE© and qacE was 98.02%, 94.06% and 0 respectively. Conclusion Pseudomonas aeruginosa has high resistance to some drugs, so attention should be paid to rational drug use. The carriage rates of of two antiseptic resistance genes exceeded 90%, indicating the need to strengthen research on the mechanism of antiseptic resistance research and rational use of disinfectants

Objective To analyze the epidemiological characteristics and influencing factors of pulmonary infection in the elderly, and to construct a risk prediction model. Methods Stratified cluster sampling was used to randomly select 683 elderly patients in Zhangjiakou First Hospital as the investigation subjects. Sputum specimens were collected and sent for bacterial isolation, culture, identification, and drug sensitivity test. According to whether the patients had pulmonary infection, they were divided into pulmonary infection group (n=315) and non-pulmonary infection group (n=368). The clinical data of the two groups such as age, sex, COPD, and ICU admission were analyzed. Univariate analysis and logistic regression analysis were used to analyze the influencing factors of pulmonary infection in elderly patients, and a risk prediction model was established. Results A total of 331 strains of pathogenic bacteria were detected in 315 patients with pulmonary infection, and there were 207 strains (62.54%) of gram-negative bacteria detected, mainly including 95 strains (28.70%) of Acinetobacter baumannii and 71 strains (21.45%) of Klebsiella pneumoniae. There were 169 strains (26.28%) of gram-positive bacteria detected, mainly 68 strains (20.54%) of Staphylococcus aureus. In addition, there were 25 strains of fungi (7.55%). There were no significant differences in gender, smoking history, history of COPD, asthma, and stroke between the two groups (P>0.05). The proportion of patients aged≥70, mechanical ventilation, admission to ICU and recent respiratory tract infection in the experimental group was significantly higher than that in the control group (P<0.05). Multivariate logistic regression analysis showed that age, smoking history, mechanical ventilation, and ICU admission were independent risk factors for pulmonary infection in elderly patients (P<0.05). According to the above four independent influencing factors and corresponding regression coefficient of each factor, the prediction model of pulmonary infection in elderly patients was constructed, Z=-5.948+1.198× (age) +1.281×(smoking history) +2.029×(mechanical ventilation) +1.211×(ICU admission). Conclusion Lung infection in elderly patients in our hospital is dominated by gram-negative bacilli. Antibiotics should be rationally selected according to drug sensitivity results. Age≥70 years old and COPD can increase the risk of pulmonary infection in elderly patients, and the prediction model constructed can effectively predict the occurrence of pulmonary infection in elderly patients.

Objective:To explore the epidemiological characteristics and the antibiotic resistance of Streptococcus pneumoniae isolates, and to provide the evidence for the rational use of antimicrobial agents to treat Streptococcus pneumoniae infection. Methods:The positive microbiological laboratory identification and antimicrobial susceptibility testing of Streptococcus pneumoniae from sputum of children with respiratory infections during January 2010 to December 2017 in Children′s Hospital of Soochow University were retrospectively analyzed. The positive rates of Streptococcus pneumoniae of different genders, ages, years and seasons were compared. The annual detection rates and trends of drug resistance of Streptococcus pneumoniae to penicillin, amoxicillin and cefotaxime were analyzed by Mann-Kendall trend test. The seasonal decomposition of time series was conducted to assess the association between Streptococcus pneumoniae detection rate and season. Enumeration data was compared using χ2 test. Results:Of the 88 480 sputum specimens, the total positive rate of Streptococcus pneumoniae was 10.3%(9 081/88 480). The detection rates of Streptococcus pneumoniae in children aged 0 to <0.5 years old, 0.5 to <2 years old, 2 to <3 years old, 3 to <5 years old, and 5 to <15 years old were 4.2%(1 407/33 224), 13.1%(3 191/24 390), 14.9%(2 417/16 252), 17.9%(1 474/8 246) and 9.3%(592/6 368), respectively. The difference was statistically significant ( χ2=2 421.6, P<0.01). The detection rates were 8.1%(1 321/16 306) from January to March, 10.9%(2 194/20 207) from April to June, 8.5%(2 141/25 058) from July to September, and 12.7%(3 425/26 909) from October to December. The discrepancy of positive rates in different seasons showed statistical significance ( χ2=311.5, P<0.01). During 2010 to 2017, significant decreases in antibiotic resistant rates of Streptococcus pneumoniae to penicillin, amoxicillin and cefotaxime were detected (tau=-0.93, -0.93 and -0.71, respectively, all P<0.05). Conclusions:The detection rate of Streptococcus pneumoniae in sputum of children with respiratory infections may present seasonal pattern and vary between different ages of children. The resistance to β-lactam antibiotics has declined.

Objective:To estimate the hospitalization rate of Haemophilus ( H.) influenzae associated community-acquired pneumonia in children under 5 years in Suzhou. Methods:From 2010 to 2014, medical records and bacteriology results of children under 5 years hospitalized with community-acquired pneumonia in Children's Hospital of Soochow University were collected, retrospectively. Detection rate of H. influenzae was describe. The hospitalization rate of H. influenzae associated community-acquired pneumonia was estimated using the number of local children in urban area of Suzhou, which was obtained from the immunization platform of Suzhou Center for Disease Prevention and Control. Results:A total of 28 043 hospitalized pneumonia cases were included from 2010 to 2014, in which 19 526 (69.63%) had bacteriological examination. The overall detection rate of H. influenzae was 11.06% (2 160/19 526), and children aged 12-23 months had the highest positive rate (14.29%, 550/3 850), and the rate was higher during winter-spring than during summer-autumn ( χ 2=455.11, P<0.01). The average hospitalization rate of H. influenzae associated pneumonia in children under 5 years was 760.36/100 000 (95% CI: 733.70/100 000-787.01/100 000), which was higher in winter and spring (898.79/100 000 and 1 249.52/100 000) than in summer and autumn (514.35/100 000 and 359.04/100 000), and the hospitalization rate was higher in boys (942.12/100 000) than in girls (563.76/100 000), the differences were all significant ( P<0.01). The highest hospitalization rate was observed in children aged 1-5 months (2 478.31/100 000) and the hospitalization rate decreased with age ( χ 2=2 129.80, P<0.01). Conclusion:There was a considerable burden of H. influenzae associated community-acquired pneumonia in children under 5 years in Suzhou, especially in children under 6 months.

Objective To understand serotypes and clinical manifestation of children with invasive pneumococcal disease (IPD) in Suzhou,so as to find a better strategy for reducing the incidence and mortality of IPD. Methods Eighty children with IPD were enrolled into our study from January 2011 to December 2015. The data of epidemiology,serotype,clinical manifestation,laboratory results and prognosis were collected and analyzed. Results The mortality of 80 children with IPD was 17. 5%(14/80). Sixty percent of them were younger than 2 years old,and 78. 6% of 14 dead cases were younger than 2 years old,the median age of dead group 0. 68 (0. 45,2. 07) years was younger than 1. 61 (0. 85,3. 45) years of survival group ( P <0. 05). The incidence rates of hyperpyrexia,vomiting and somnolence in dead group were higher than those in survival group before admission ( P <0. 05), the incidence rates of shock, DIC, respiratory failure, AKI, seizure or coma in dead group were higher than those in survival group ( P<0. 05). The coincidence rate between choice of antibiotics before admission and drug sensitivity test was 15. 0%(12/80),the mortality of coincident group (coincidence between choice of antibiotics and drug sensitivity test) 8. 3% was lower than 16. 2% of non-coincident group with no statistical differences ( P>0. 05). The drug resistance rates of 80 pneumococcus to Erythromycin,Clindamycin,Tetracycline,Sulfamethoxazole,Penicillin,Cefotaxime,Amoxi-cillin,Chloramphenicol,Vancomycin and Levofloxacin were 100% (80/80),98. 8% (79/80),88. 8%(71/80),71. 3%(57/80),48. 8%(39/80),32. 5%(26/80),8. 8%(7/80),5. 0%(4/80),0(0/80) and 0(0/80) respectively. Eight serotypes of 80 IPD cases were listed in descending order:6B(25. 5%,20/80),14 (23. 8%,19/80),19F(15. 0%,12/80),19A(15. 0%,12/80),23F(8. 8%,7/80),20(5. 0%,4/80),9V (5. 0%,4/80) and 15B/C(2. 5%,2/80),and 6 serotypes of 14 dead cases were:6B(35. 7%,5/14),14 (28. 6%,4/14),19F(14. 3%,2/14),19A(7. 1%,1/14),23F(7. 1%,1/14) and 20(7. 1%,1/14); the coverage of IPD serotypes of 7-valent pneumococcal conjugate vaccine (PCV7) 77. 5%(62/80) was lower than 92. 5%(74/80) of 13-valent pneumococcal conjugate vaccine (P <0. 05). Conclusion Majority of dead cases of IPD is always younger than 2 years. The low coincidence rate of choices of antibiotics to inva-sive pneumococcus outpatient and low rate of PCV immunization in China are responsible for the high mortal-ity of IPD. Timely recognition of continuous hyperpyrexia, vomiting and somnolence in early stage and appropriate use of antibiotics is the key to improve the outcome of IPD. Thirteen-valent pneumococcal conju-gate vaccine immunization provides a robust strategy for reducing the incidence and mortality of IPD.

Objective To explore the risk factors for childhood death from pneumococcal meningitis.Methods The data of 32 hospitalized children were retrospectively analyzed,who were diagnosed as pneumococcal meningitis and enrolled in the Affiliated Children′s Hospital of Soochow University from November 201 0 to December 201 5.The subjects were divided into the death group and survival group according to their prognosis.The clinical characteristics and laboratory data were compared between 2 groups.Results Between the death group and survival group,there were significant statistically differences in shock within 24 hours after admission(63.6% vs 1 4.3%,P =0.01 3),as well as endotracheal tube intubation(1 00.0% vs 23.8%,P <0.001 ),the levels of cerebrospinal fluid(CSF)IgG[(491 .27 ± 203.53)mg/L vs (267.24 ±1 88.07)mg/L,P =0.006],IgM[(1 1 5.72 ±79.1 9)mg/L vs (32.80 ±28.52)mg/L, P =0.006],IgA[59.52(1 5.51 ,75.69)mg/L vs 1 8.77(9.33,27.54)mg/L,P =0.023],CSF leukocyte[330.00 (1 50.00,380.00)×1 06 /L vs 870.00 (403.00,6 1 60.00)×1 06 /L,P =0.009 ],CSF protein [(4 047.00 ± 1 942.1 6)mg/L vs (2 470.62 ±1 259.94)mg/L,P =0.009],CSF adenosine deaminase (ADA)[35.20(1 8.90, 87.20)U /L vs 8.80(3.05,23.78)U /L,P =0.001 ],serum sodium[(1 30.21 ±2.85)mmol/L vs (1 32.83 ±3.69) mmol/L,P =0.049],serum lactic acid (LA)[4.40 (2.60,5.70)mmol/L vs 2.40 (1 .75,4.50)mmol/L,P =0.01 3],serum C -reactive protein (CRP)[(95.87 ±65.40)mg/L vs (1 65.61 ±83.05)mg/L,P =0.022],serum lactate dehydrogenase (LDH)[81 3.40(465.20,2 31 0.70)U /L vs 359.20(257.85,405.90)U /L,P =0.001 ], platelet[(1 63.82 ±1 64.86)×1 09 /L vs (295.71 ±1 30.29)×1 09 /L,P =0.01 9]and positive rate of blood culture (90.9% vs 47.6%,P =0.023)between the death group and survival group.Conclusions The risk factors associated with mortality in pediatric SPM include shock within 24 hours after admission,endotracheal intubation,hyponatremia, thrombocytopenia,as well as high serum LA level,high serum LDH level,lower serum CRP level or cultures of blood and CSF double positive.

Objective To explore the relationship between the clinical features and the bacteria quantity confirmed by semi-quantitative culture of sputum in hospitalized infants with wheezing diseases.Methods Nine hundred and fifty-seven patients with wheezing diseases were enrolled from Jan.1,2010 to Dec.3 1,2011,and their clinical characteristics were collected.Respiratory seeretions were collected on admission by the pathogenic examination.They were grouped into 3 groups by the bacteria quantity,and the predictive analytics statistical saftware 20.0 was used to analyze the relationship between the clinical features and the bacteria quantity confirmed by semi-quantitative culture of sputum.Results 1.A total of 372(38.87％,372/957 cases)patients had positive sputum cuhures,and there were 585 patients in 0 + group,225 patients in 1 +-2 + group,147 patients in 3 +-4 + group;the main pathogens in 1 +-2 + group were haemophilus influenza (24.89％,56/225 cases) and streptococcus pneumonia (16.00％,36/225 cases) ;the main pathogens in 3 +-4 + group were streptococcus pneumonia(54.42％,80/147 cases) and haemophilus influenza(8.84％,13/147 cases).2.Presence of siblings,cyanosis,neutrophils and C-reactive protein were higher in 3 +-4 + group when compared with those of 0 + group,shortness of breath was common in 1 +-2 + group.3.Multinomial Logistic regression analysis identified the presence of siblings,residence,passive smoking,course of disease and cyanosis were identified as risk factors in 3 +-4 + group; gender,fever peak ＞ 38.5 ℃,breast-feeding,passive smoking,age,course of disease and cyanosis were as risk factors in 1 +-2 + group.4.Severe pneumonia was common in 3 +-4 + group.Conclusions Bacterial are often detected in infants hospitaled with wheezy episodes,and bacteria quantity is correlated with clinical presentation.Severe pneumonia is common in higher bacteria quantity group.

Objective To analyze the resistance genes in a muhidrug resistant Klebsiella pneumoniae (MDRKP) strain.Methods A MDRKP strain was isolated from bronchoalveolar lavage fluid in Pediatric Intensive Care Unit of Children's Hospital Affiliated to Soochow University in February 2012.Acquired resistance genes to beta-lactams,aminoglycosides,quinolones,ompK35 and ompK36 gene for outer membrane porin protein,and carbapenems targeting PBP2 gene were analyzed by PCR and verified by DNA sequencing.Results Acquired resistance genes TEM-1,SHV-1 to beta-lactam antimicrobial agents and aac(6′)-I b to aminoglycoside antimicrobial agents were positive in the strain of MDRKP.While 16S rRNA methylase,ompK35 and ompK36 genes for outer membrane porin protein were negative.Compared with susceptible strains,there were 9 synonymous mutations in PBP2 gene sequence of this MDRKP strain,but the amino acid sequences were the same.No mutation in quinolone resistance determining region (QRDR) was observed.Conclusion The multidrug resistance of the isolated Klebsiella pneumoniae strain may be related to 2 kinds of beta-lactam acquired resistance genes,1 kind of aminoglycoside acquired resistance gene,ompK35 and ompK36 genes defects and synonymous mutation in PBP2 gene.

Objectives To analyze pathogen distribution and antimicrobial resistance of bacilli among children with otitis media. Methods Pathogenic bacteria was isolated from children with suppurative otitis media. The VITEK32 was used for iden-tification. The bacterial susceptibility testing was done by Kirby-Bauer method. According to CLSI standard the antimicrobial susceptibility was determined. Results From Jan 2010 to Dec 2012, 425 children with suppurative otitis media were examined. 347 strains were isolated, of which the detectable rate was 81.65%. The detectable rate of bacteria and fungus was 93.37%(324/347) and 6.63%(23/347), respectively. Among bacteria, the detectable rate of streptococcus pneumoniae was 40.92%(142/347) and staphylococcus aureus was 33.43%(116/347). The detectable rate of haemophilus influenza was 7.78%(27/347). The preva-lence of streptococcus pneumoniae is high in children aged 1-3years, with detectable rate at 47.09%. There was no statistical dif-ference among different age groups. The prevalence of methicillin-resistant staphylococcus aureus (MRSA) in middle ear secre-tion was 1.11%(5/45), 18.75%(9/48)and 30.43%(7/23)in 2010, 2011 and 2012 respectively, with no statistical difference (χ2=3.86, P=0.145). The prevalence of penicillin-resistant streptococcus pneumoniae (PRSP) in middle ear secretion was 9.26%, 3.92%and 27.03%in 2010, 2011 and 2012 respectively, with statistical difference (χ2=11.47, P=0.003). Conclusions Choosing correct therapy according to the result of middle ear secretion culture and antibiotics sensitive test can increase the recovery rate of otitismedia.

Objectives To investigate the changes and features of drug resistance in Haemophilus inlfuenzae (Hi) isolated from children with infection diseases in Suzhou. Methods One thousand two hundred and twenty-two Hi strains isolated from clinical specimens were collected from January 2011 to June 2012. Antimicrobial susceptibility was tested by Kirby-Bauer me-thod, andβ-lactamase was analyzed by chromogenic nitroceifn method. Then strains were divided into four groups according to their speciifc resistance patterns:①β-lactamase positive strains (except for cefuroxime-resistant strains),②β-lactamase negative ampicillin-resistant (BLNAR) strains,③cefuroxime-resistant strains, and④other resistant strains. Results The resistance of iso-lated Hi from children in Suzhou area to ampicillin, co-trimoxazole, cefaclor, tetracycline, chloramphenicol, azithromycin, cefu-roxime, ampicillin/sulbactam was 32.7%, 76.7%, 27.4%, 14.3%, 10.2%, 8.4%, 6.9%and 4.3%, respectively, and the detection rate in four groups was 29.0%, 2.6%, 6.9%, 41.2%, respectively. Multi-resistant strains were mainly distributed in Group①and Group②, accounting for 67.5%and 81.3%of each group. Azithromycin, tetracycline and chloramphenicol showed high antimicrobial activity against BLNAR and cefuroxime-resistant Hi strains. The positive rate of resistance toβ-lactamase was 30.8%. The rates of resistance to cefuroxime, cefaclor, ampicillin/sulbactam and cotrimoxazole inβ-lactamase-positive ampicillin-resistant strains are signiifcantly different from those inβ-lactamase-negative ampicillin-resistant strains. Conclusions The resistance feature of Hi isolated from children in Suzhou shows signiifcant changes, including new appearance of cefuroxime-resistant strain, a rapid increase in resistance to azithromycin, and a large proportion of multidrug-resistant strains. The rapid increase in BLNAR and the emergence of cefuroxime-resistant strains have become the new resistance pattern of Hi in this area.