Molecular epidemiology of serotype 19A Streptococcus pneumoniae isolated from children in Beijing, 1997-2006

Background Despite the prevalence of Streptococcus pneumoniae serotype 19A, the molecular characteristics of this serotype are yet to be fully elucidated. The aim of this study was therefore to determine the homology of the serotype 19A in China. Methods Pulsed-field gel electrophoresis and multilocus sequence typing were done to these forty-nine serotype 19A isolates to investigate the relationship between the strains prevalent in Beijing and other regions. Results From 1997 to 2006, the percentage of serotype 19A isolates increased. The susceptibility rate to penicillin and amoxicillin decreased and the resistance rate to cefuroxime increased. ST320 was the most prevalent ST, followed by ST3546. There were six new STs identified in our study. The serotype 19A strains were classified into six different pulsed-field gel electrophoresis （PFGE） patterns. ST320, which was associated with two different PFGE patterns （A and D）, accounted for 32 isolates, and ST3546, which was associated with two PFGE patterns （B and E）, accounted for eight isolates. Conclusions From 2003 onwards, ST320 was the most common ST and the rate of resistance to cefuroxime increased significantly. Further long-term surveys of Streptococcus pneumoniae serotype 19A are required to monitor ST prevalence and antimicrobial resistance, in this important human pathogen.

Inhibition of methicillin-resistant Staphylococcus aureus by the compound Qingre granules

Background The infection rate of methicillin-resistant Staphylococcus aureus （MRSA） is increasing yearly due to the overprescription of antibiotics. Traditional Chinese compound medicines are less inclined to induce bacterial resistance in the clinical setting because of their multi-acting mechanisms. However, most current research is limited to bacteriostasis in vitro using single extracts or formulations. Plasma pharmacology is an in vitro method, using what is called ＂medicine serum＂. The aim of this study was to investigate whether the medicine serum of compound Qingre granules （QRKL） alone or in combination with antibiotics may treat MRSA infection in the clinic. Methods An animal model of MRSA resistance was created by injecting rabbits with the standard strain of MRSA ATCC43300. Infected rabbits were treated with QRKL by intragastric administration. Sixty minutes after the last intragastric administration, serum was obtained from the rabbits by heart puncture to obtain what is termed ＂medicine serum＂. The minimum inhibitory concentration （MIC） of QRKL, medicine serum alone, or serum combined with antibiotics was assessed by agar dilution. Results were compared with the growth of sixteen isolates of MRSA. Results The MIC of QRKL to the standard strain ATCC43300 was 10.00 mg/ml. The MICgo of vancomycin was 1.00 pg/ml, which, when combined with QRKL, dropped to 0.50 lJg/ml. The MICg0 of cefuroxime alone was 512.00 pg/ml. This level also decreased to 256.00 tJg/ml when combined with QRKL. The addition of QRKL thus significantly reduced the MIC of both cefuroxime and vancomycin compared with antibiotics alone （P 〈0.01）. The MICgo of vancomycin with medicine serum decreased to 0.50 pg/ml, and the MIC of vancomycin with medicine serum also descended compared with using vancomycin alone （P 〈0.01）. Conclusions The growth of MRSA can be inhibited by QRKL or medicine serum of QRKL in vitro. The addition of QRKL results in increased sensitivity of MRSA to vancomycin and this may provide a novel treatment for patients with MRSA infection.

Enterococcal urinary tract infections: eight years experience at a regional hospital in Trinidad, West Indies

OBJECTIVE: To investigate the prevalence of significant enterococcal isolates from urine and determine what factors are associated with the increased prevalence, with particular reference to antibiotic susceptibilities. METHODS: Retrospective analysis over an 8-year period of hospital laboratory records of urinary isolates of enterococci was done. Species were identified via colony morphology, growth in 6.5% sodium chloride and their ability to hydrolyze esculin in the presence of 40% bile salts. Susceptibility testing via the disc diffusion technique with 9 commonly used antibiotics was also done as defined by the National Committee for Clinical Laboratory Standards. RESULTS: From 39,881 urine specimens, 9116 (22.9%) were culture positive. Of this 9116, 1001 (11.0%) were enterococci, the 4th most common urinary isolate. E. coli was the most common (36.2%). Most enterococci were from pediatric patients (28.4%) and the urology unit (24.5%). All enterococci were fully sensitive to ampicillin and augmentin (amoxicillin-clavulanic acid). Sensitivity to gentamicin decreased significantly from 79% in 1990 to 58% in 1997 (P