Adnan Al-Lahham

Antimicrobial Susceptibility of Streptococcus pneumoniae in Eight European Countries from 2001 to 2003

ABSTRACT Susceptibility testing results for Streptococcus pneumoniae isolates (n = 2,279) from eight European countries, examined in the PneumoWorld Study from 2001 to 2003, are presented. Overall, 24.6% of S. pneumoniae isolates were nonsusceptible to penicillin G and 28.0% were resistant to macrolides. The prevalence of resistance varied widely between European countries, with the highest rates of penicillin G and macrolide resistance reported from Spain and France. Serotype 14 was the leading serotype among penicillin G- and macrolide-resistant S. pneumoniae isolates. One strain (PW 158) showed a combination of an efflux type of resistance with a 23S rRNA mutation (A2061G, pneumococcal numbering; A2059G, Escherichia coli numbering). Six strains which showed negative results for mef(A) and erm(B) in repeated PCR assays had mutations in 23S rRNA or alterations in the L4 ribosomal protein (two strains). Fluoroquinolone resistance rates (levofloxacin MIC ≥ 4 μg/ml) were low (Austria, 0%; Belgium, 0.7%; France, 0.9%; Germany, 0.4%; Italy, 1.3%; Portugal, 1.2%; Spain, 1.0%; and Switzerland, 0%). Analysis of quinolone resistance-determining regions showed eight strains with a Ser81 alteration in gyrA; 13 of 18 strains showed a Ser79 alteration in parC. The clonal profile, as analyzed by multilocus sequence typing (MLST), showed that the 18 fluoroquinolone-resistant strains were genetically heterogeneous. Seven of the 18 strains belonged to new sequence types not hitherto described in the MLST database. Europe-wide surveillance for monitoring of the further spread of these antibiotic-resistant S. pneumoniae clones is warranted.

Macrolide-Resistant Streptococcus pneumoniae and Streptococcus pyogenes in the Pediatric Population in Germany during 2000-2001

ABSTRACT In a nationwide study in Germany covering 13 clinical microbiology laboratories, a total of 307 Streptococcus pyogenes (mainly pharyngitis) and 333 Streptococcus pneumoniae (respiratory tract infections) strains were collected from outpatients less than 16 years of age. The MICs of penicillin G, amoxicillin, cefotaxime, erythromycin A, clindamycin, levofloxacin, and telithromycin were determined by the microdilution method. In S. pyogenes isolates, resistance rates were as follows: penicillin, 0%; erythromycin A, 13.7%; and levofloxacin, 0%. Telithromycin showed good activity against S. pyogenes isolates (MIC90 = 0.25 μg/ml; MIC range, 0.016 to 16 μg/ml). Three strains were found to be telithromycin-resistant (MIC ≥ 4 μg/ml). Erythromycin-resistant strains were characterized for the underlying resistance genotype, with 40.5% having the efflux type mef(A), 38.1% having the erm(A), and 9.5% having the erm(B) genotypes. emm typing of macrolide-resistant S. pyogenes isolates showed emm types 4 (45.2%), 77 (26.2%), and 12 (11.9%) to be predominant. In S. pneumoniae, resistance rates were as follows: penicillin intermediate, 7.5%; penicillin resistant, 0%; erythromycin A, 17.4%; and levofloxacin, 0%. Telithromycin was highly active against pneumococcal isolates (MIC90 ≤ 0.016 μg/ml; range, 0.016 to 0.5 μg/ml). The overall resistance profile of streptococcal respiratory tract isolates is still favorable, but macrolide resistance is of growing concern in Germany.

Molecular Epidemiology of Macrolide-Resistant Streptococcus pneumoniae Isolates in Europe

ABSTRACT In many European countries, the level of pneumococcal resistance to macrolides has now passed the level of resistance to penicillin G. A total of 82 erythromycin A-resistant isolates of Streptococcus pneumoniae were collected by 11 laboratories in seven European countries. All of the isolates were tested for antimicrobial susceptibility, analyzed for clonal relatedness by multilocus sequence typing, and characterized for macrolide resistance genotypes. The prevalence of the macrolide resistance genotypes varied substantially between countries. In France (87.5% of all strains), Spain (77.3%), Switzerland (80%), and Poland (100%), strains were predominantly erm(B) positive, whereas higher levels of mef(A)-positive strains were reported from Greece (100%) and Germany (33.3%). Macrolide resistance was caused by the oligoclonal spread of some multilocus sequence types, but significant differences in clonal distribution were noted between France and Spain, countries from which high levels of macrolide resistance have been reported. Overall, sequence type 81 (Spain23F-1 clone) was by far the most widespread. The mainly erm(B)-positive serotype 14 clone (sequence type 143), first reported in Poland in the mid-1990s, is now widespread in France.

Resistance to Erythromycin and Telithromycin in Streptococcus pyogenes Isolates Obtained between 1999 and 2002 from Greek Children with Tonsillopharyngitis: Phenotypic and Genotypic Analysis

ABSTRACT Since the late 1990s, the prevalence of erythromycin-resistant Streptococcus pyogenes has significantly increased in several European countries. Between January 1999 and December 2002, 1,577 isolates of S. pyogenes were recovered from children with tonsillopharyngitis living in various areas of Western Greece. Erythromycin resistance was observed in 379 (24%) of the 1,577 isolates. All erythromycin-resistant strains along with 153 randomly selected erythromycin-susceptible S. pyogenes isolates were tested for their antimicrobial susceptibility, resistance phenotypes, and genotypes. Representative isolates underwent emm gene sequence typing. Isolates with reduced susceptibility to telithromycin (MIC, ≥2 μg/ml) were studied for multilocus sequence type, L22, L4, and 23S rRNA mutations. Of the total 379 erythromycin-resistant isolates, 193 (50.9%) harbored the mef(A) gene, 163 (43%) erm(A), 1 (0.3%) mef(A) plus erm(A), and 22 (5.8%) the erm(B) gene. Among the erythromycin-susceptible isolates, emm 1 (25%), emm 2 (12.5%), and emm 77 (12.5%) predominated. Furthermore, among the erythromycin-resistant isolates, emm 4 (30.6%), emm 28 (22.2%), and emm 77 (12.5%) prevailed. Resistance to telithromycin was observed in 22 (5.8%) of the erythromycin-resistant isolates. Sixteen (72.7%) of the 22 isolates appeared to be clonally related, since all of them belonged to emm type 28 and multilocus sequence type 52. One of the well-known mutations (T2166C) in 23S rRNA, as well as a new one (T2136C), was detected in erythromycin- and telithromycin-resistant isolates. High incidence of macrolide resistance and clonal spread of telithromycin resistance were the characteristics of the Greek S. pyogenes isolates obtained from 1999 to 2002.

Ribosomal Mutations Conferring Resistance to Macrolides in Streptococcus pneumoniae Clinical Strains Isolated in Germany

ABSTRACT Among a collection of 4,281 pneumococcal isolates, 7 strains isolated in Germany had an unusual macrolide resistance phenotype. The isolates were found to have multiple mutations in the 23S rRNA and alterations in the L4 ribosomal protein. One strain had an amino acid alteration in the L22 ribosomal protein.

Antimicrobial resistance of Streptococcus pneumoniae recovered from outpatients with respiratory tract infections in Germany from 1998 to 1999: results of a national surveillance study.

ABSTRACT Clinically significant pneumococcal isolates were prospectively collected from outpatients with respiratory tract infections by 19 different clinical microbiology laboratories in Germany. Resistance rates in a total of 961 isolates were as follows: penicillin, 6.6%; clarithromycin, 10.6%; tetracycline, 13.9%; and levofloxacin, 0.1%. Among 324 isolates from children, pneumococcal serotypes 19F (17.0%), 23F (13.0%), and 6B (11.7%) were the predominant types.

Susceptibility to tuberculosis is associated with TLR1 polymorphisms resulting in a lack of TLR1 cell surface expression

Human TLR1 plays an important role in host defense against Mycobacterium tuberculosis. Our aim was to analyze the association of the loss of TLR1 surface expression and TLR1 SNPs with susceptibility to TB. TLR1neg and TLR1pos cells from healthy individuals were identified by flow cytometry and compared by sequencing. TLR1 expression was measured using quantitative real‐time PCR and immunoblotting. TLR1 SNP analyses of healthy individuals and TB patients from EU‐C and Ghana were performed, and association of the TLR1 genotypes with increased risk of developing TB was statistically evaluated. Lack of TLR1 surface expression accompanied by impaired function was strongly associated with TLR1 SNP G743A. Genotyping of EU‐C controls and TB patients revealed an association of TLR1 743A/1805G alleles [OR 2.37 (95% CI 1.13, 4.93), P=0.0219; OR 2.74 (95% CI 1.26, 6.05), P=0.0059] as well as TLR1neg 743AA/1805GG versus TLR1pos genotypes 743AG/1805TG [OR 4.98 (95% CI 1.64, 15.15), P=0.0034; OR 5.70 (95% CI 1.69, 20.35), P=0.0015] and 743AG + GG/1805TG + TT [OR 3.54 (95% CI 1.29, 9.90), P=0.0086; OR 4.17 (95% CI 1.52, 11.67), P=0.0025] with increased susceptibility to TB. No association of G743A with TB was found in Ghana as a result of a low frequency of genotype 743AA. Our data gain new insights in the role of TLR1 in M. tuberculosis defense and provide the first evidence that TLR1 variants are associated with susceptibility to TB in a low‐incidence country.

Clonal relatedness of erythromycin-resistant Streptococcus pyogenes isolates in Germany.

ABSTRACT In a nationwide study in Germany, a total of 381 Streptococcus pyogenes were collected. Erythromycin A-resistant strains were characterized for the underlying resistance genotype, showing 55.6% had the efflux type mef(A), 31.5% had erm(A), and 13.0% had erm(B). A total of 23 different multilocus sequence types were observed.

Superantigen Genes Are More Important than the emm Type for the Invasiveness of Group A Streptococcus Infection

BACKGROUND In this study, we examined the role of superantigen genes and emm genotypes of clinical Streptococcus pyogenes isolates collected in Germany between 1997 and 2003. METHODS Multiplex polymerase chain reaction for all 11 currently known superantigen genes and sequencing for emm types were used. RESULTS Using a 2-step explorative data analysis procedure, we found that after combined analysis of superantigen genes and emm types, only the superantigen genes spea1-spea3, spem, and spea4 have a predictive value for invasiveness, with odds ratios of 7.992, 3.209, and 2.323, respectively. The predictive value for invasiveness of emm1 was lost after combined analysis because of the association between emm type and the highly predictive superantigen genes. On the other hand, presence of the superantigen gene ssa and of emm77 are predictors of noninvasiveness, with odds ratios of 0.370 and 0.271, respectively. CONCLUSIONS These results indicate that the presence of superantigen genes is more important for the invasiveness of group A Streptococcus infection than emm type and may be the connection between the high-risk HLA type of the host and the pathogen. Furthermore, we found a very clear correlation between the presence of the genes spea1-spea3 and the presence of the gene emm1, which indicates that the relationship between emm1 and invasiveness is based on the superantigen gene profile. Our data suggest that the superantigen gene profile is of high importance for the clinical outcome of group A Streptococcus infections.

Molecular Characterization of the First Telithromycin-Resistant Streptococcus pneumoniae Isolate in Germany

ABSTRACT A total of 486 Streptococcus pneumoniae isolates were collected in 2003 and 2004 in Germany and revealed the following resistance rates: penicillin G (7.2%) and erythromycin A (18.9%). Telithromycin exhibited good in vitro activity (MIC at which 90% of the isolates tested were inhibited, 0.125 μg/ml). However, one erm(B)-positive isolate was found to be telithromycin resistant (MIC, 8 μg/ml).