Objective: To analyze the antimicrobial resistance profile in Chinese children. Methods: This was a prevalence survey. From January 1 through December 31, 2016, the isolates were collected from 10 tertiary children hospitals in China. Antimicrobial susceptibility testing was carried out by routine laboratory methods. The penicillin susceptibility of streptococcus pneumonia and Meropenem susceptibility of gram-negative bacteria were detected by E-test and disk diffusion method respectively. Antimicrobial susceptibility results were interpreted according to the criteria of Clinical and Laboratory Standards Institute (CLSI) Guideline 2016. The data of antimicrobial susceptibility testing of isolates from either the different patients (neonatal group and non-neonatal group) or various sources were analyzed by WHONET 5.6 software. Results: A total of 56 241 isolates were collected, of which 41.5% (23 328 isolates) were gram-positive organisms and 58.5% (32 886 isolates) gram-negative organisms. The five leading pathogens were Escherichia coli (7 995/56 214, 14.2%), Straphylococcus aureus (6 468/56 214, 11.5%), Streptococcus pneumonia (6 225/56 214, 11.1%), Haemophilus influenza (5 435/56 214, 9.7%) and Klebsiella pneumonia (4 523/56 214, 8.0%). The Meropenem resistance rates of Klebsiella pneumonia, Enterobacter cloacae, Escherichia coil, Pseudomonas aeruginosa, Acinetobacter baumonia isolates were 27.4% (326/1 189) , 8.1% (29/358) , 2.0% (27/1 362) , 19.5% (34/174) , 49.7% (230/463) in neonatal group and 15.4% (512/3 327) , 4.8% (40/841) , 2.3% (151/6 564) , 13.7% (252/1 840) , and 53.4% (860/1 611) in non-neonatal group. The Methicillin-resistant Staphylococcus aureus (MRSA) rates of neonatal group and non-neonatal group were 46.2% (649/1 404) and 33.3% (1 668/5 010) . The penicillin non-susceptible rates of Streptococcus pneumonia in the two groups were 17.6% (6/34) and 18.2% (1 121/6 158) respectively. The β-lactamase positive rates of Haemophilus pneumonia isolates in the neonatal group and non-neonatal groups were 33.8% (47/139) and 44.4% (2 345/5 282) respectively. Conclusion This investigation highlights the worrisome trend of antimicrobial resistance in children, especially among neonatal patients in China.

Objective: To describe the clinical characteristics of pneumococcal infections and drug resistance of Streptococcus pneumoniae isolates from children's hospitals, which would provide reference for preventing and treating pneumococcal diseases. Methods: This was a prevalence survey. In this study, the age, specimen type, monthly distribution characteristics, and antimicrobial resistance of Streptococcus pneumoniae isolates from 9 children's hospitals in China were investigated between January 1, 2016 and December 31, 2016. The WHONET 5.6 software was used to analyze the antibiotic susceptibility of Streptococcus pneumoniae. The comparison of rates was performed by Chi-square test. Results: A total of 6 200 isolates of streptococcus pneumoniae were obtained, namely, 95.1% (5 876/6 177) from the respiratory tract specimens, 2.2% (136/6 177) from blood specimens and 0.4% (24/6 177) from cerebrospinal fluid specimens. The isolates were mainly from children older than 1 and younger than 5 years (54.7%, 3 381/6 185) . Most of strains (33.2%, 1 184/3 563) were isolated in November, December and January. Streptococcus pneumoniae isolates were completely sensitive to vancomycin (100.0%, 6 189/6 189) , linezolid (100.0%, 6 030/6 030) , moxifloxacin (100.0%, 3 064/3 064) , highly sensitive to levofloxacin (99.8%, 5 528/5 540), ertapenem (98.8%, 3 024/3 061) and lowly sensitive to erythromycin (1.7%, 102/6 016), clindamycin (3.7%, 116/3 136), and tetracycline (5%, 244/4 877), respectively. According to the parenteral susceptibility breakpoints for non-meningitis isolates, the sensitivity of Streptocococus pneumoniae to penicillin from children's hospital of Chongqing Medical University (49.3%, 892/1 809) was significantly lower than those of other hospitals (χ²=1 268.161, P<0.05) . Conclusions Streptococcus pneumoniae is mainly isolated from respiratory tract, from children older than 1 and younger than 5 years and during November to January in tertiary children's hospital of China. The Streptococcus pneumoniae from children is highly sensitive to vancomycin, linezolid, moxifloxacin, levofloxacin. There are also significant differences in the sensitivity of penicillin for Streptococcus pneumoniae from different hospitals.

Objective To investigate the distribution and drug resistance of carbapenem-resistant Enterobacteriaceae ( CRE) isolated from children in China. Methods CRE strains were collected in 10 ter-tiary children's hospitals of China from January 1, 2016 to December 31, 2017. Antimicrobial susceptibility of the clinical strains was detected with disk diffusion method ( KB method) and automated method. The re-sults were analyzed according to the Clinical and Laboratory Standards Institute ( CLSI) Standards published in 2017. WHONET 5. 6 software was used to retrospectively analyze the distribution characteristics and drug resistance of these strains. Results A total of 3065 CRE clinical strains were isolated from children with an overall prevalence of 7. 7％ and among them, 13. 5％ were isolated in neonatal group and 5. 8％ in non-neo-natal group. The detection rate of CRE in 2017 was higher than that in 2016 (9. 7％ vs 5. 7％). Among the 3065 CRE strains, there were 1912 strains of Klebsiella pneumoniae (62. 0％), 667 strains of Escherichia coli (22. 0％), 206 strains of Enterobacter cloacae (7. 0％), 56 strains of Klebsiella aerogenes (1. 8％) and 47 strains of Serratia marcescens (1. 5％). Most of the strains were isolate in neonatology departments including neonatal intensive care units (NICU) and intensive care units (ICU), accounting for 44. 8％ and 19. 7％, respectively. Respiratory tract (61. 8％), urine (19. 4％) and blood (5. 7％) specimens were the main sources of CRE isolates. Results of antimicrobial susceptibility test showed that the CRE strains were highly resistant to carbapenem antibiotics such as imipenem, meropenem and ertapenem, as well as penicillins and most cephalosporins (79. 6％-100％), especially those isolated in the neonatal group (P<0. 05). Children had relatively low resistance rates to aminoglycosides such as amikacin (19. 7％) and fos-fomycin (11. 9％), fluoroquinolones such as levofloxacin (37. 7％) and ciprofloxacin (43. 3％), and tige-cycline (3. 8％). Currently, no polymyxin B-resistant strains were isolated. Conclusions The prevalence of common CRE strains in children in 2017 was higher than that in 2016, especially in newborns. Drug re-sistance in CRE strains isolated from neonates to common antibiotics was more severe, suggesting that great attention should be paid to it and timely measures should also be taken.

Objective:To investigate the clinical characteristics of pediatric methicillin-resistant Staphylococcus aureus (MRSA) infection and the antibiotic sensitivity of the isolates. Methods:The clinical data of children with MRSA infection and antibiotic sensitivity of the isolates from 11 children′s hospitals in Infectious Diseases Surveillance of Paediatrics (ISPED) group of China between January 1, 2018 and December 31, 2018 were collected retrospectively. The children′s general condition, high-risk factors, antimicrobial therapy and prognosis, differences in clinical disease and laboratory test results between different age groups, and differences of antibiotic sensitivity between community-acquired (CA)-MRSA and hospital-acquired (HA)-MRSA were analyzed. The t test and Wilcoxon rank sum test were used for statistical analysis of the quantitative data and Chi-square test were used for comparison of rates. Results:Among the 452 patients, 264 were males and 188 were females, aged from 2 days to 17 years. There were 233 cases (51.5%) in the ≤1 year old group, 79 cases (17.5%) in the>1-3 years old group, 29 cases (6.4%) in the >3-5 years old group, 65 cases (14.4%) in the >5-10 years old group, and 46 cases (10.2%) in the>10 years old group. The main distributions of onset seasons were 55 cases (12.2%) in December, 47 cases (10.4%) in February, 46 cases (10.2%) in November, 45 cases (10.0%) in January, 40 cases (8.8%) in March. There were 335 cases (74.1%) CA-MRSA and 117 (25.9%) cases HA-MRSA. Among all cases, 174 cases (38.5%) had basic diseases or long-term use of hormone and immunosuppressive drugs. During the period of hospitalization, 209 cases (46.2%) received medical interventions. There were 182 patients (40.3%) had used antibiotics (β-lactams, glycopeptides, macrolides, carbapenems, oxazolones, sulfonamides etc) 3 months before admission. The most common clinical disease was pneumonia (203 cases), followed by skin soft-tissue infection (133 cases), sepsis (92 cases), deep tissue abscess (42 cases), osteomyelitis (40 cases), and septic arthritis (26 cases), suppurative meningitis (10 cases). The proportion of pneumonia in the ≤1 year old group was higher than the >1-3 years old group,>3-5 years old group,>5-10 years old group,>10 years old group (57.5% (134/233) vs. 30.4% (24/79), 31.0% (9/29), 38.5% (25/65), 23.9% (11/46), χ 2=17.374, 7.293, 7.410, 17.373, all P<0.01) The proportion of skin and soft tissue infections caused by CA-MRSA infection was higher than HA-MRSA (33.4% (112/335) vs. 17.9% (21/117), χ 2=10.010, P=0.002), and the proportion of pneumonia caused by HA-MRSA infection was higher than CA-MRSA (53.0% (62/117) vs. 42.1% (141/335), χ 2=4.166, P=0.041). The first white blood cell count of the ≤1 year old group was higher than that children > 1 year old ((15±8)×10 9/L vs. (13±7)×10 9/L, t=2.697, P=0.007), while the C-reactive protein of the ≤1 year old group was lower than the 1-3 years old group,>5-10 years old group,>10 years old group (8.00 (0.04-194.00) vs.17.00 (0.50-316.00), 15.20 (0.23-312.00), 21.79(0.13-219.00) mg/L, Z=3.207, 2.044, 2.513, all P<0.05), there were no significant differences in procalcitonin (PCT) between different age groups (all P>0.05). After the treatment, 131 cases were cured, 278 cases were improved, 21 cases were not cured, 12 cases died, and 10 cases were abandoned. The 452 MRSA isolates were all sensitive to vancomycin (100.0%), linezolid (100.0%), 100.0% resistant to penicillin, highly resistant to erythromycin (85.0%, 375/441), clindamycin (67.7%, 294/434), less resistant to sulfonamides (5.9%, 23/391), levofloxacin (4.5%, 19/423), gentamicin (3.2%, 14/438), rifampicin (1.8%, 8/440), minocycline (1.1%, 1/91). The antimicrobial resistance rates were not significantly different between the CA-MRSA and HA-MRSA groups (all P>0.05). Conclusions:The infection of MRSA is mainly found in infants under 3 years old. The prevalent seasons are winter and spring, and MRSA is mainly acquired in the community. The main clinical diseases are pneumonia, skin soft-tissue infection and sepsis. No MRSA isolate is resistant to vancomycin, linezolid. MRSA isolates are generally sensitive to sulfonamides, levofloxacin, gentamicin, rifampicin, minocycline, and were highly resistant to erythromycin and clindamycin. To achieve better prognosis. clinicians should initiate anti-infective treatment for children with MRSA infection according to the clinical characteristics of patients and drug sensitivity of the isolates timely and effectively.

Silver nanoparticles were prepared by chemical reduction. Fusarium graminearum was used as the test strain. To study the inhibition of F. graminearum by silver nanoparticles, we studied the activities of protective enzymes superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), and the contents of osmotic adjustment substances soluble protein, soluble sugar and malonaldehyde (MDA) in F. graminearum. Silver nanoparticles inhibited F. graminearum and the inhibitory effect was increased with the concentration of silver nanoparticles. The inhibition rate of 10 μg/mL silver nanoparticles was more than 90% and EC50 was 0.59 μg/mL. When the treating time prolonged (2, 4, 6, 8 and 10 h), the activity of SOD, CAT and POD increased firstly and then declined. SOD, POD and CAT reached the maximum at 4 hours, and decreased to minimum at 10 hours. Silver nanoparticles also increased the MDA content and reduced the soluble sugar and protein contents in pathogens. These results indicated that cell integrity was destroyed in the presence of silver. This may be one of the inhibiting mechanisms of silver nanoparticles on the growth of F. graminearum.