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Objective To investigate the distribution and antimicrobial resistance profile of the common pathogens isolated during the period from 2009 to 2015.Methods All the bacterial strains isolated from pediatric inpatients in Beijing Children's Hospital during the period from 2009 to 2015 were analyzed. Antimicrobial susceptibility was determined by disk diffusion method and Phoenix 100 Automated Microbiology System. Results were analyzed according to the guidelines of CLSI (2014) using WHONET 5.6 software.Results The total strains were 26630. The most common gram-positive isolates were Streptococcus pneumoniae,Staphylococcusaureusand coagulase-negative Staphylococcus (CNS), while the most frequently isolated gram-negative microorganisms were Klebsiella spp.,Pseudomonas aeruginosa and Escherichia coli. The prevalence of S. pneumoniae was up to 25.7 % (4101/15973) in all respiratory tract specimens. About 50.2 % of the S. pneumoniae isolates were not susceptible to penicillin. The prevalence of methicillin-resistant strains was 20.6 % in S. aureus (MRSA) and 87.8 % in coagulase negative Staphylococcus (MRCNS) on average. The prevalence of MRSA increased from 11.1 % in 2009 to 29.8 % in 2015. No S. pneumoniae or staphylococcal strains were found resistant to vancomycin or linezolid. The Enterococcus strains were still highly susceptible to vancomycin and linezolid. Overall 0.3 % of the Enterococcus faecium isolates were resistant to vancomycin. The extended-spectrum beta-lactamases (ESBLs) producing strains accounted for 71.4 % -78.1 % of E. coli and 65.1 % - 76.9 % of K. pneumoniae isolates. The carbapenem-resistant E. coli and K. pneumoniae were reported for the first time in 2010, but in 2014, the strains resistant to carbapenems had increased to more than 7 % in E. coli, and higher than 20 % in K. pneumoniae. In 2015, up to 27.7 % and 25.7 % of P. aeruginosa isolates were resistant to imipenem and meropenem, respectively, and 59.9 % of the A. baumannii isolates were resistant to imipenem and meropenem. Beta-lactamase was positive in 46.3 % of the H. influenzae isolates. Conclusions MRSA and the carbapenem-resistant strains of E. coli,K. pneumoniae and A. baumannii are still on the rise in pediatric inpatients, which poses a serious threat to clinical practice and implies the importance of strengthening infection control.
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Objective To investigate the etiology, epidemiologic features and drug resistance tendency of acute infectious diarrhea among children in Beijing area. Methods Enteric pathogenic bacteria were isolated, cultured and identified for serotype from the stool specimens of children with the initial clinical diagnosis of acute bacterial diarrhea in the intestinal clinic from January to October in 2009 ,and the antibiotic susceptibility of bacteria was tested by disk diffusion method. The cluster A rotavirus antigen was also detected by the qualitative technique of immunochromatographic double-antibody sandwich assay. Results Of the 256 stool specimens, 87 strains of 4 species of pathogenic bacteria were detected with the detectable rate of 34. 0% ,of which 2 strains were detected in one stool sample ,including 40 strains of salmonella (46. 0%) ,23 strains of shigella (26. 4%) ,2 strains of diarrheogenic escherichia coli (2. 3%) and 22 strains of staphylococcus aureus (25.3%). The positively detected patients consisted of 54 males and 32 females with the ratio of 1.69∶1 ,of whom 55 cases (64. 0%) were under 2 years of age. Of the 13 strains of shigella, 13 were sonnei shigella (56. 5%). And of the 22 strains of staphylococcus aureus,20 were detected among the infants under 1 year of age. The rates of crug resistance to certain antibiotics were lower in salmonella than in shigella (ampicillin :65. 0% vs. 95.7% ;compound sulfamethoxazole:20. 0% vs. 78. 3% ;ciprofloxacin:7.5% vs.8. 7% ;ceftriaxone: 15.0% vs. 73.9%). Of the 256 stool specimens ,47 were found positive for cluster A rotavirus,of whom 13 were also positive in stool bacteria culture. Conclusion Salmonella is the major pathogen among children with bacterial diarrhea in Beijing in 2009, and sonnei shigella is the main epidemic strains of shigella diarrhea. lnfants under 2 years of age are the susceptible population of the above two species of bacteria, while staphylococcus aureus mainly infect the infants under 1 years of age. Multi-resistance in shigella is still serious. The incidence of mixed infections of bacteria and rotavirus increases in children with infectious diarrhea.
ABSTRACT
Objective To analyze the antibiotic resistance of the carbapenem no-susceptibility Enterobacteriaceae isolated from pediatric patients and the resistant genes of carbapenemase-producing.Methods In all,46 carbapenem no-susceptibility Enterobacteriaceae strains were isolated from patients at Beijing Children's Hospital between January 2008 and December 2010.Agar dilution method recommended by the Clinical and Laboratory Standards Institute was used to examine the minimum inhibitory concentrations (MICs) of 14 antimicrobial agents.Phenotypic testing for carbapenemase-producing was conducted using Hodge test and double-disk synergy test.PCR was used to detect the expression of the carbapenemase-related genes KPC,GES,IMI/NMC-A,SME,IMP,VIM,GIM,SPM,SIM and OXA.WHONET5.6 was used to perform resistance analysis.Results Among 46 carbapenem no-susceptibility Enterobacteriaceae strains,26 (56.5％) were Klebsiella pneumoniae strains,13(28.3％ ) were Enterobacter cloacae and 7( 15.2％ ) were Escherichia coli.The rates of imipenem and meropenem no-susceptibility Klebsiella pneumoniae were 69.2％ and 80.8％,Enterobacter cloacae were 76.9％ and 100％ and Escherichia coli were 85.7％ and 100％,respectively.40(87.0％ ) strains were positive of Hodge test.41 (89.1％) strains were positive of doubledisk synergy test.38 (82.6％) were positive for the IMP genotype.The carbapenemase-related genes were not found in other 8 strains.Conclusion The prevalence of carbapenem no-susceptibility Enterobacteriaceae strains in Klebsiella pneumoniae isolates is relatively high in children.Resistance to imipenem was lower than that to meropenem from Klebsiella pneumoniae,Enterobacter cloacae and Escherichia coli strains.Many carbapenem no-susceptibility Enterobacteriaceae isolated from pediatric patients carry the blaIMP gene.No the KPC gene was found.