Invasive
            <i>Streptococcus pneumoniae</i>
            in France: Antimicrobial Resistance, Serotype, and Molecular Epidemiology Findings from a Monthly National Study in 2000 to 2002

The prevalence and mechanisms of macrolide resistance among 1,007 clinical pneumococcal isolates collected in Finland were investigated. Of these, 217 (21.5%) were resistant to erythromycin and 11% to clindamycin. Among the erythromycin-resistant isolates, mef(E) was present in 95 isolates (44%), mef(A) was present in 12 isolates (6%), and erm(B) was present in 90 isolates (41%). A double mechanism, mef(E) and erm(B), was detected in five isolates (2%). Ribosomal mutation was detected in 14 (6%) macrolide-resistant isolates in which no other determinant was found. Based on the telithromycin MICs, two groups of isolates were formed: 83.3% of the isolates belonged to a major group for which the telithromycin MIC range was <0.008 to 0.063 g/ml, and 16.7% belonged to a minor group for which the telithromycin MIC range was 0.125 to 8 g/ml. All except three isolates in the minor population carried a macrolide resistance gene.

Section: Discussioncontrasting

confidence: 48%

“…The proportion of resistant isolates ranges from 3 to 80% in different countries (2,7,20,22,23,26,33). Macrolide resistance is mediated by two main mechanisms in pneumococci: target site modification and drug efflux.…”

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confidence: 99%

Prevalence and Molecular Genetics of Macrolide Resistance among Streptococcus pneumoniae Isolates Collected in Finland in 2002

Rantala

Huikko

Huovinen

et al. 2005

“…Within the last 10 years, macrolide resistance in S. pneumoniae has emerged on a dramatic scale throughout Europe (4,16). This study shows that resistance to macrolides in Germany has drastically increased over the last 12 years.…”

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confidence: 84%

Clonal Spread of mef -Positive Macrolide-Resistant Streptococcus pneumoniae Isolates Causing Invasive Disease in Adults in Germany

Linden

Al‐Lahham

Haupts

et al. 2007

Isolates (3,845) obtained from German adults with invasive pneumococcal disease between 1992 and 2004 were investigated. Of these, 430 isolates (11.2%) were erythromycin A nonsusceptible. Macrolide resistance genotypes and multilocus sequence types were determined. Among the isolates, 35.6% were erm(B) positive and 63.5% were mef positive. Over the study period, the frequency of resistance rose significantly from 2.2 to 17.0% (P < 0.001). A serotype 14, sequence type 9 clone was the most widespread.Streptococcus pneumoniae continues to be a significant cause of morbidity and mortality in humans. The worldwide increase in antibiotic resistance in pneumococci has become a serious infectious-disease problem within the last 20 years. Macrolide resistance in S. pneumoniae is usually caused by the presence of the erm(B) or the mef(E) or mef(A) resistance determinant. The erm(B) gene encodes a 23S rRNA methylase that confers resistance to 14-, 15-, and 16-member-ring macrolides, lincosamides, and streptogramin B. The mef(E) and mef(A) genes, which are carried by different genetic elements, encode an efflux pump that leads to resistance to 14-and 15-member-ring macrolides (the M phenotype) (14,20). Other rare mechanisms of macrolide resistance are changes in a highly conserved region of domain V of 23S rRNA, which plays a key role in macrolide binding, and in ribosomal proteins L4 and L22 (3, 5, 18, 21).Multilocus sequence typing (MLST) is a recently developed technique that produces unambiguous molecular typing data by using the sequences of seven loci to obtain an allelic profile of each strain (6, 11; http://www.mlst.net). The present study used this technique to analyze the genetic relatedness of clinical erythromycin A-resistant strains of S. pneumoniae isolated from adults with invasive pneumococcal disease in Germany.The German National Reference Center for Streptococci received consecutive isolates from 126 clinical microbiological laboratories throughout Germany. Inclusion criteria were isolation from an individual of Ͼ16 years and isolation from a normally sterile body site.MIC testing, serotyping, the determination of resistance genotypes and phenotypes, and MLST of 62 randomly selected macrolide-resistant strains were performed as described previously (11, 13).Multilocus sequence types were analyzed using the program eBURST, which displays relationships between closely related isolates of a bacterial species or population. eBURST, unlike cluster diagrams, trees, or dendrograms, uses a simple but appropriate model of bacterial evolution in which an ancestral (or founding) genotype increases in frequency in the population and, while doing so, begins to diversify to produce a cluster of closely related genotypes that are all descended from the founding genotype. This cluster of related genotypes is referred to as a clonal complex (8; http://eburst.mlst.net). A phylogenetic tree using maximum likelihood was created with the program Puzzle (19; http://genius.dkfz-heidelberg.de).A total of 3,845 isolates were con...

“…The difference was more dramatic in the group of strains showing the higher levofloxacin MIC (2 g/ml), which represented 2.6% of the American sample and 12.2% in the present study: 71% (10 of 14) versus 0% (0 of 29). It could be explained by (i) the difference in the levofloxacin MIC distribution and the low frequency of high-level levofloxacin-resistant strains (0.4% versus 1.8% in the United States), (ii) the methodology (systematic screening versus sampling) and origin of the strains (bloodstream versus noninvasive strains), and (iii) the low level of levofloxacin consumption in France compared to the United States, which was significantly associated with the increasing rate of FQR in this country (2,5,8,9,12,17,20,27,30). However, these results should be confirmed with a larger number of strains.…”

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confidence: 99%

“…A sample of 236 clinical FQsusceptible strains was randomly selected from the annual survey program performed between 2000 and 2003 in 105 general hospitals as part of the Collège de Bactériologie-Virologie Hygiène des Hôpitaux (ColBVH) Study Group and screened for mutations. The MICs were determined by an agar dilution method and interpreted according to Clinical and Laboratory Standards Institute guidelines as previously described (11,12,22,23). Two specific primers and TaqMan probes were designed to detect wildtype alleles at positions 79 and 83 of the parC QRDR of S. pneumoniae (nucleotide positions 3852 to 3854 and 3864 to 3866, respectively) ( Table 2).…”

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confidence: 99%

New Real-Time PCR Assay Using Locked Nucleic Acid Probes To Assess Prevalence of ParC Mutations in Fluoroquinolone-Susceptible Streptococcus pneumoniae Isolates from France

Decousser

Methlouthi

Pina

et al. 2006

Self Cite

A real-time PCR assay with locked nucleic acid probes was developed to screen mutations at codons 79 and 83 of the Streptococcus pneumoniae parC gene. Only silent mutations were detected among 236 French invasive fluoroquinolone-susceptible strains. This test could be useful for some high-risk patients or in national surveys.The worldwide spread of multidrug-resistant clones has led to the increasing use of fluoroquinolones (FQs) in the therapy of Streptococcus pneumoniae infections (21). In some countries the increase of FQ resistance (FQR) in that species and some clinical failures have been reported (5,9,13,16,18). The mechanisms of FQR mostly correspond to stepwise mutations in the quinolone resistance-determining regions (QRDR) of ParC and GyrA, two subunits of the FQ targets (DNA gyrase and the topoisomerase IV) (29). The low-level resistance firststep parC mutants (FSPC) were implicated in the selection following levofloxacin therapy of the highly resistant parC-gyrA double mutants (7,16). FSPC mutants are classified as susceptible to FQs according to the standard breakpoints (19,26,27,28). Sequencing of QRDR parC gene was considered the gold standard. We described a real-time PCR assay with TaqMan probes including locked nucleic acid (LNA) bases to detect mutations in codon 79 or 83 of parC, the two codons being mostly implicated in FQR in S. pneumoniae (5,8,9,16). The LNA base is a bicyclic RNA analogue that increases the stability of the DNA/LNA mixmer (14). When probes include LNA bases, the melting temperature of the duplex DNA target/probe and then the specificity of the test increase. This assay was tested for an epidemiological survey that included a panel of controls and S. pneumoniae invasive strains, using sequencing as control method.Control strains including wild-type and ParC mutant strains were tested repeatedly (Table 1). A sample of 236 clinical FQsusceptible strains was randomly selected from the annual survey program performed between 2000 and 2003 in 105 general hospitals as part of the Collège de Bactériologie-Virologie Hygiène des Hôpitaux (ColBVH) Study Group and screened for mutations. The MICs were determined by an agar dilution method and interpreted according to Clinical and Laboratory Standards Institute guidelines as previously described (11,12,22,23). Two specific primers and TaqMan probes were designed to detect wildtype alleles at positions 79 and 83 of the parC QRDR of S. pneumoniae (nucleotide positions 3852 to 3854 and 3864 to 3866, respectively) ( Table 2). DNA crude extracts were prepared from a loopful of overnight plate culture suspended in 200 l of distilled water, using a rapid DNA extraction kit (QIAamp DNA MiniKit; QIAGEN, Courtaboeuf, France) according to the manufacturer's instructions. The PCR experiments were performed on a Smart Cycler (Cepheid, Sunnyvale, Calif.); 5 l of DNA extract was transferred into a 20-l PCR mixture containing 0.25 M concentrations of the primers parC3 and parC4, 0.25 M concentrations of each probe, and 12.5 l of the Smart Kit (Euroge...