Changing trends in antimicrobial susceptibility of Streptococcus pneumoniae isolates in Taiwan, 2006-2007
ABSTRACT Multiple antibiotic-resistant clones of Streptococcus pneumoniae have spread throughout the world and continue to evolve under the selective pressure of antibiotics and vaccines. The aim of this study is to assess the susceptibility of S. pneumoniae isolates and to analyze the resistance trends in Taiwan.
Antimicrobial susceptibility tests were performed on 152 nonmeningeal isolates of S. pneumoniae that were collected from 13 different hospitals around Taiwan from 2006-2007. Tests were performed using the broth microdilution method according to recommendations of the Clinical and Laboratory Standards Institute.
The minimal inhibitory concentrations (MIC(50)/MIC(90)) of penicillin, cefotaxime, vancomycin, and moxifloxacin were 0.5/1.0, 0.25/1.0, 0.25/0.5, and 0.06/0.12 μg/mL, respectively. The susceptibility rates of penicillin, cefotaxime, vancomycin, and moxifloxacin were 99.3%, 99.3%, 100%, and 98.7%, respectively. However, if the meningitis breakpoints were applied to these nonmeningeal isolates, the susceptibility rates of penicillin and cefotaxime were reduced to 18.4% and 76.3%, respectively. Compared with the findings from previous studies in Taiwan, our results show that the percentage of S. pneumoniae isolates with a penicillin MIC of 0.12-1.0 μg/mL increased from 43.3% in 1996-1997 to 73.7% in 2006-2007 (p < 0.001). The percentage of S. pneumoniae isolates with a cefotaxime MIC of 1.0 μg/mL increased from 11.3% in 1996-1997 to 23.0% in 2006-2007 (p < 0.001). Regarding the serial MIC intervals of the four antimicrobial agents, there was no significant difference between bacteremic and nonbacteremic isolates.
Although nonmeningeal S. pneumoniae isolates remained susceptible to penicillin, the proportion of isolates with a penicillin MIC of 0.12-1.0 μg/mL or cefotaxime MIC of 1.0 μg/mL increased during the past decade in Taiwan. The ever-increasing resistance of S. pneumoniae has a great impact on the treatment of meningitis.
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ABSTRACT: Background This study investigated the molecular characteristics of azithromycin-resistant Streptococcus pneumoniae in Taiwan.MethodsA total of 486 non-duplicate isolates of azithromycin-resistant S. pneumoniae recovered from various clinical sources of patients treated at 22 different hospitals in Taiwan from 2006 to 2010. The presence of erm(B) and mef(A) genes using duplex PCR, multilocus sequence typing (MLST), and pulsed-field gel electrophoresis of these isolates were studied.ResultsOf the isolates tested, 59% carried the erm(B) gene, 22% carried the mef(A) gene, and 19% carried both genes. The prevalence of isolates carrying the erm(B) and mef(A) genes increased from 10% (11/110) in 2006 to 25% (15/60) in 2010 (p-value¿=¿0.0136). The majority of isolates carrying both erm(B) and mef(A) genes belonged to serotypes 19 F (64%) followed by 19 F A (24%). Of these isolates, 33% were sequence type 320 (ST320), 32% were ST236, and 12% were ST271.Conclusions The increase in incidence of mef(A)/erm(B)-positive azithromycin-resistant S. pneumoniae isolates during the study period was primarily due to serotypes 19 F and 19A and ST236 and ST320.BMC Infectious Diseases 12/2014; 14(1):704. DOI:10.1186/s12879-014-0704-z · 2.56 Impact Factor
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ABSTRACT: Background Diseases caused by infectious and inflammatory microorganisms are among the most common and most severe nosocomial diseases worldwide. Therefore, developing effective agents for treating these illnesses is critical. In this study, essential oils from two tea tree species, kanuka (Kunzea ericoides) and manuka (Leptospermum scoparium), were evaluated for use in treating diseases and inflammation caused by microorganism infection. Methods Isolates of clinically common bacteria and fungi were obtained from American Type Culture Collection and from Kaohsiung Veterans General Hospital. Minimum inhibitory concentrations for Trichosporon mucoides, Malassezia furfur, Candida albicans, and Candida tropicalis were determined by the broth microdilution method with Sabouraud dextrose broth. The antibacterial susceptibility of Staphylococcus aureus, Streptococcus sobrinus, Streptococcus mutans, and Escherichia coli were determined by the broth microdilution method. A human acute monocytic leukemia cell line (THP-1) was cultured to test the effects of the essential oils on the release of the two inflammatory cytokines, tumor necrosis factor-α and interleukin-4. Results Multiple analyses of microorganism growth confirmed that both essential oils significantly inhibited four fungi and the four bacteria. The potent fungicidal properties of the oils were confirmed by minimum inhibitory concentrations ranging from 0.78% to 3.13%. The oils also showed excellent bactericidal qualities with 100% inhibition of the examined bacteria. In THP-1 cells, both oils lowered tumor necrosis factor-α released after lipopolysaccharide stimulation. Finally, the antimicrobial and anti-inflammatory effects of the oils were obtained without adversely affecting the immune system. Conclusion These results indicate that the potent antimicroorganism and anti-inflammation properties of kanuka and manuka essential oils make them strong candidates for use in treating infections and immune-related disease. The data confirm the potential use of kanuka and manuka extracts as pharmaceutical antibiotics, medical cosmetology agents, and food supplements.Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi 02/2014; DOI:10.1016/j.jmii.2013.12.009 · 1.63 Impact Factor
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ABSTRACT: Dissemination of antibiotic resistant clones is recognized as an important factor in the emergence and prevalence of resistance in pneumococcus. This study was undertaken to survey the antimicrobial susceptibility and serotypes distribution of pneumococci and to explore the circulating clones in hospitalized children in Suzhou, China. The pneumococci were isolated from the nasopharyngeal aspirates of children less than 5 years of age admitted to Soochow-University-Affiliated-Children's-Hospital with respiratory infections. The capsular serotypes were identified by multiplex polymerase chain reaction (PCR). Antimicrobial susceptibility was tested by E-test. The presence of ermB, mefA/E genes were detected by PCR and the genotypes were explored by Multilocus sequence typing (MLST). From July 2012 to July 2013, a total of 175 pneumococcal isolates were collected and all strains were resistant to erythromycin and clindamycin, about 39.4% strains were non-susceptible to penicillin G. Overall, 174 (99.4%) isolates were resistant to ≥3 types of antibiotics. Serotypes 19F (28.1%), 6B (19.7%), 19A (18.0%), and 23F (17.4%) were the most common serotypes in all identified strains. The serotypes coverage of PCV7 and PCV13 were 71.9% and 89.9%, respectively. Four international antibiotic-resistant clones, including Taiwan19F-14 (n = 79), Spain23F-1(n = 25), Taiwan23F-15(n = 7) and Spain6B-2(n = 7), were identified. The Taiwan19F-14 clones have a higher non-susceptibility rate in β-lactams than other clones and non-clone isolates (p<0.001). In addition, 98.7% Taiwan19F-14 clones were positive of both ermB and mefA/E genes, compare to 33.3% in other clones and non-clone strains. The spread of international antibiotic-resistant clones, especially Taiwan19F-14 clones, played a predominant role in the dissemination of antimicrobial resistant isolates in Suzhou, China. Considering the high prevalence of PCV7 serotypes and serotype 19A, the introduction of PCV13 may be a promising preventive strategy to control the increasing trend of clonal spread in China.PLoS ONE 04/2014; 9(4):e93752. DOI:10.1371/journal.pone.0093752 · 3.53 Impact Factor