Objective To investigate the epidemiological characteristics and antibiotic sensitivity of Salmonella infection in children with diarrhea in Zhongshan City for rational use of antibiotics.Methods A total of 6 920 stool specimens were collected from children with diarrhea including outpatients and inpatients in Zhongshan Boai Hospital from September 2009 to April 2013.Salmonella strains (n = 344)were isolated and identified by enrichment culture.The overall infection rate was 5.0%(344/6 920).Antimicrobial susceptibility was tested by VITEK-2 Compact automicroscan.Results Of the 344 strains of Sal-monella,185 (53.8%)strains were Salmonella typhimurium ,43 (12.5%)were Salmonella stanley ,29 (8.4%)were Sal-monella enteritidis .The male-to-female ratio was 1.8∶1 for the children with diarrhea.The infection rate was 68.9% (237/344)in children under 1-year old.Susceptibility testing results indicated that majority (88.9%-98.0%)of these Salmonella strains were susceptible to levofloxacin,piperacillin-tazobactam,cefepime,ceftazidime,and ceftriaxone,but to ampicillin, 39.2% of the strains were susceptible.Conclusions Most Salmonella infections in Zhongshan City were caused by Salmonella typhimurium,followed by Salmonella stanley and Salmonella enteritidis .Such infections usually peak in summer and autumn seasons.The chidren under 1-year old were more susceptible to Salmonella infections.Higher incidence of infection is associat-ed with boys.Antibiotics should be chosen reasonably and prudently based on antimicrobial sensitivity testing.

Objective To investigate the distribution characteristics of pathogenic bacteria among different seasons and ages in children lower respiratory tract infection.Methods To retrospectively analyze the results of bacterial culture in pediatric outpatients and inpatients with lower respiratory tract infections in our hospital from September 2014 to August 2015.The pathogenic bacterial detection situation of lower respiratory tract infection among different age groups and different were statistically analyzed.Results A total of 2 809 pathogenic bacterial strains were isolated from 4 629 lower respiratory tract specimens,and detection rate was 60.7%.The pathogenic bacteria distribution was different among different age groups.Haemophilus influenzae (33.3%) ranked the first place in the lower respiratory infection among children aged from 19 d to 7 year old.The detection rates of Haemophilus parainfluenzae,Moraxella catarrhalis and staphylococcus aureus had obvious seasonality,while Streptococcus pneumoniae had no obvious seasonality.Conclusion Pathogenic bacteria causing lower respiratory tract infections in children are different from those in adults,which are affected by age and seasonal change.

Objective To understand the status quo of Salmonella infection in the patients with infectious diarrhea in Zhongshan city .Methods The fecal samples collected from 6 417 outpatients or inpatients with infection diarrhea in our hospital from January 2010 to December 2013 were performed the Salmonella culture ,isolation and identification and at the same time the serological clas-sification and the pulsed-field gel electrophoresis (PFGE) were performed .Results Among 6 417 samples ,460 strains of Salmonel-la were detected with the isolation rate of 7 .17% .Salmonella infection was dominated by children infection .The Salmonella infec-tion rate in children aged less than 1 years was 52 .4% (241 cases) ,followed by children aged 1- < 3 years ,which was 36 .7% (169 cases) .In the serological classification ,the most of detected Salmonella was salmonella typhimurium 46 .1% ,accounting for 46 .1% , Stanley salmonella accounting for 13 .5% and Salmonella enteritidis accounting for 8 .7% .The PFGE homology analysis showed that in the XbaI enzyme digestion spectral band ,26 PFGE band types had 100% homology .Conclusion Salmonella is one of the main pathogenic bacteria causing diarrhea and serious impact on health ,which is worthy of clinicians to pay attention to .

Objective To investigate the antibiotic resistance of Haemophilus influenzae isolates collected from the children with respiratory tract infection for rational use of antibiotics in clinical practice .Methods The H .influenzae strains were isolated from children and subjected to antimicrobial susceptibility testing by Kirby-Bauer method .Nitrocefin disc test was used to detect the production of beta-lactamases .WHONET 5 .6 software was used to analyze the susceptibility data .Results A totalof1256strainsof H.influenzaewereisolated.About37.8% ,65.5% and16.5% ofthe1256strainsof H.influenzae were resistant to ampicillin ,trimethoprim-sulfamethoxazole ,and ampicillin-sulbactam ,respectively .Less than 10 .0% of these strains were resistant to any other antibiotics tested .Beta-lactamase was produced in 33 .5% of the 1 256 strains of H . influenzae .Conclusions The H . influenzae strains in this study are mainly resistant ampicillin and trimethoprim-sulfamethoxazole .About 80 .0% of these H . influenzae strains were still susceptible to cefaclor ,ampicillin-sulbactam , cefixime ,ceftazidime ,azithromycin ,ciprofloxacin ,meropenem and rifampin .The primary mechanism of ampicillin resistance in Haemophilus is production of beta-lactamases .

Objective To understand the carrying status and drug resistance of streptococcus agalactiae in the genital tract of pregnant women.Methods The vaginal discharge from pregnant women was collected for conducting the bacterial culture.The iso-lated streptococcus agalactiae was performed the identification and the drugs susceptibility test by the VITEK 2 fully automatice bacterial identification analyzer.Results Among 1 042 samples,streptococcus agalactiae was isolated in 6 cases with the separation rate of 5.4%.The drug sensitivity test showed the Streptococcus agalactiae was highly sensitive to penicillin,cefazolin,vancomycin, linezolid and nitrofurantoin.The intermediate strains or drug resistant strains were not found.The sensitive rate to levofloxacin, moxifloxacin and clindamycin,erythromycin,tetracycline were 84.0%,84.0%,71.4%,39.3% and 8.9% respectively.Conclusion The carrying rate of streptococcus agalactiae in pregnant women is not high in our hospital.Penicillin and cefazolin should be as the drug of first choice for therapy and the clincal and laboratory nould payattention to detection of streptococcus agalactiae in pregnant women.

Objective To investigate the antimicrobial resistance profile of the Streptococcus pneumoniae strains isolated from respiratory tract of children in Zhongshan Boai Hospital, Guangdong Province for better management of such infections. Methods The sputum samples were collected from respiratory tract of children in pediatric outpatient and inpatient from May 2013 to August 2017. S. pneumoniae strains were isolated and identified and their susceptibility to antimicrobial agentswas determined. Results The prevalence of S. pneumoniae was 10.6％ (2 963/28 006) in the sputum samples. S. pneumoniae was mainly isolated from children under 6 years old, and relatively higher in winter and spring. About 43.0％ of the S. pneumoniae isolates was associated with mixed infection, especially Moraxella catarrhalis and Haemophilus influenzae. About 6.0％ of the S. pneumoniae isolates were non-susceptible to penicillin, 59.3％ non-susceptible to ceftriaxone, and more than 95％ non-susceptible to erythromycin, clindamycin or tetracycline. However, more than 95％ of the isolates were susceptible to chloramphenicol or ofloxacin. No S. pneumoniae isolate was found resistant to rifampin, linezolid or vancomycin. Conclusions The respiratory tract infection caused by S. pneumoniae of children is increasing year by year, which is associated with age, season, and higher rate of mixed infection. These data showed that penicillin non-susceptible S. pneumoniae is highly prevalent in Zhongshan. More than 95％ of the S. pneumoniae isolates from children are resistant to erythromycin, clindamycin or tetracycline. S. pneumoniae isolates should be closely monitored for the emergence of multidrug resistant strains. Appropriate control measures must be taken according to the results of susceptibility testing.