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1.  Molecular epidemiology, antimicrobial susceptibilities and resistance mechanisms of Streptococcus pyogenes isolates resistant to erythromycin and tetracycline in Spain (1994–2006) 
BMC Microbiology  2012;12:215.
Group A Streptococcus (GAS) causes human diseases ranging in severity from uncomplicated pharyngitis to life-threatening necrotizing fasciitis and shows high rates of macrolide resistance in several countries. Our goal is to identify antimicrobial resistance in Spanish GAS isolates collected between 1994 and 2006 and to determine the molecular epidemiology (emm/T typing and PFGE) and resistance mechanisms of those resistant to erythromycin and tetracycline.
Two hundred ninety-five out of 898 isolates (32.8%) were erythromycin resistant, with the predominance of emm4T4, emm75T25, and emm28T28, accounting the 67.1% of the 21 emm/T types. Spread of emm4T4, emm75T25 and emm28T28 resistant clones caused high rates of macrolide resistance. The distribution of the phenotypes was M (76.9%), cMLSB (20.3%), iMLSB (2.7%) with the involvement of the erythromycin resistance genes mef(A) (89.5%), msr(D) (81.7%), erm(B) (37.3%) and erm(A) (35.9%).
Sixty-one isolates were tetracycline resistant, with the main representation of the emm77T28 among 20 emm/T types. To note, the combination of tet(M) and tet(O) tetracycline resistance genes were similar to tet(M) alone reaching values close to 40%. Resistance to both antibiotics was detected in 19 isolates of 7 emm/T types, being emm11T11 and the cMLSB phenotype the most frequent ones. erm(B) and tet(M) were present in almost all the strains, while erm(A), mef(A), msr(D) and tet(O) appeared in less than half of them.
Spanish GAS were highly resistant to macrolides meanwhile showed minor resistance rate to tetracycline. A remarkable correlation between antimicrobial resistance and emm/T type was noticed. Clonal spread of emm4T4, emm75T25 and emm28T28 was the main responsable for macrolide resistance where as that emm77T28 clones were it to tetraclycline resistance. A wide variety of macrolide resistance genes were responsible for three macrolide resistance phenotypes.
PMCID: PMC3490898  PMID: 22998619
GAS; emm gene; PFGE; Macrolide resistance; Tetracycline resistance
3.  B:2a:P1.5 Meningococcal Strains Likely Arisen from Capsular Switching Event Still Spreading in Spain▿  
Journal of Clinical Microbiology  2008;47(2):463-465.
Eighteen clustered cases of meningococcal disease associated with B:2a:P1.5 strains doubled the annual incidence up to 4.3 × 105 in Navarra, Spain, in 2007. Eleven percent of cases were fatalities, and 74% of cases were individuals 10 to 24 years old. This is the third cluster associated with this strain in northern Spain since 2001.
PMCID: PMC2643662  PMID: 19091814
4.  Nalidixic Acid Disk for Laboratory Detection of Ciprofloxacin Resistance in Neisseria meningitidis▿  
Recently the CLSI recommended a disk diffusion method and breakpoints for meningococci which include breakpoints derived for nalidixic acid which serve as surrogate markers for gyrase A mutations associated with diminished fluoroquinolone susceptibility. This study presents the application of this methodology to a panel of 57 meningococcal strains isolated in Spain that include all levels of susceptibility to ciprofloxacin. In conclusion, the most useful method to predict isolates with gyrA mutations that decrease the activity of fluoroquinolones is the use of 30-μg nalidixic acid disks.
PMCID: PMC2630652  PMID: 19015355
5.  PorB2/3 Protein Hybrid in Neisseria meningitidis 
Emerging Infectious Diseases  2008;14(4):688-689.
PMCID: PMC2570943  PMID: 18394304
PorB; meningococci; mosaic; letter
6.  Sequencing of Neisseria meningitidis penA Gene: the Key to Success in Defining Penicillin G Breakpoints 
Testing of susceptibility to penicillin G by E-test and sequencing of an internal fragment of the penA gene were done for 43 meningococcal strains. Those strains for which the MIC was ≥0.094 μg/ml showed mosaic alleles, so 0.094 μg/ml is suggested as the penicillin G intermediate breakpoint when E-test is used.
PMCID: PMC310191  PMID: 14693567
7.  Capsule Switching among C:2b:P1.2,5 Meningococcal Epidemic Strains after Mass Immunization Campaign, Spain 
Emerging Infectious Diseases  2002;8(12):1512-1514.
A mass immunization campaign for 18-month to 19-year-olds was undertaken in Spain in 1996–1997 because of an epidemic of serogroup C meningococcal disease associated with a C:2b:P1.2,5 strain belonging to the A4 lineage. Surveillance for the “capsule-switching” phenomenon producing B:2b:P1.2,5 isolates was undertaken. Of 2,975 meningococci characterized, B:2b:P1.2,5 and B:2b:P1.2 antigenic combinations were found in 18 isolates; 15 meningococci were defined as serogroup B belonging to the A4 lineage.
PMCID: PMC2738524  PMID: 12498676
Capsular switching; meningococcal strains; immunization campaign

Results 1-7 (7)