S. Berrón

Streptococcus pneumoniae in children in Spain: 1990–1999

This study analyses the serogroups/types (SGTs) and resistance to penicillin and erythromycin of 3921 strains isolated from 1990 to 1999 in children aged 0–14 y in Spanish hospitals of all the autonomous communities. Based on the age of the children, strains have been divided into five groups: 0–6 mo, <6–1 y, <1–2y, <2–5 y and 5 y. While only eight SGTs were responsible for 80% of the infections in children from 6 mo to 2 y of age, this number increased to 11 and 16 for the groups 2–5 y and <5–14 y, respectively. SGTs 6, 14 and 19 were prevalent in blood and otic exudates. SGTs 1, 4, 5, 12 and 18 were more frequent in invasive disease but serotype 3 was clearly associated with otitis. Serotypes 1 and 5 were quite significant in children of over 2 y of age, and this should be taken into account in future vaccine formulations.

Multiply antibiotic-resistant Streptococcus pneumoniae recovered from Spanish hospitals (1988-1994) : novel major clones of serotypes 14, 19F and 15F

We analysed a collection of 95 multiply antibiotic-resistant pneumococci, recovered since 1988 from 14 Spanish hospitals, that have MICs > or = 0.25 microgram benzylpenicillin ml-1. The majority of the isolates were of serogroups 14, 23, 6, 19 and 15, which are currently the serogroups mainly associated with multiresistance in Spain. All of the serogroup 23 isolates were members of the major Spanish serotype 23F multiresistant clone. Similarly, most of the serogroup 6 isolates were members of the major multiresistant serotype 6B clone, or variants of this clone. Eighteen of the 24 isolates of serogroup 19 were members of a highly penicillin-resistant clone that appears to be a serotype 19F variant of the major Spanish serotype 23F multiresistant clone. Eighteen of the 25 isolates of serotype 14 were members of a previously uncharacterized highly penicillin-resistant clone. Thirteen of the 16 isolates of serogroup 15 were members of a single previously unreported clone of serotype 15F that had moderate levels of resistance to penicillin. Approximately 65% of the multiresistant pneumococci that are currently circulating in Spain were members of the three new clones of serotype 14, 15F and 19F that we describe here, or the previously described serotype 6B and 23F clones. The other 35% of isolates were minor variants of the major clones, unrelated minor clones, and unique isolates, many of which appeared to have arisen by horizontal gene transfer events.

Increasing incidence of meningococcal disease in Spain associated with a new variant of serogroup C

Serogroup B has been the main cause of meningococcal disease in Spain since at least 1979, but in recent years an increase in the prevalence of infection due to serogroup C meningococci has been detected. In 1996, for the first time, most cases of meningococcal disease were caused by serogroup C strains. The sero/subtype of all serogroup C meningococci received from 1993 to June 1996 was determined, and the results showed that C∶2b∶P1.2,5, the most common phenotype in 1995 and 1996 (63% and 65%, respectively), represented only 4.8% of strains in 1993. The C∶2b∶P1.2,5 epidemic strains appear to be responsible for the high prevalence of serogroup C in Spain. One hundred fifty-one randomly selected serogroup C strains were analyzed by multilocus enzyme electrophoresis, ribotyping, and pulsedfield gel electrophoresis. Pulsed-field gel electrophoresis provided the most accurate information: more than 80% of the C∶2b∶P1.2,5 and C∶2b∶P1.2 isolates exhibited one of two very closely related profiles, while most of the C:2b:NST and C∶2b∶P1.5 strains had a pattern located at a genetic distance of 0.24 from those two profiles. The results show that C∶2b∶P1.2,5 strains represent a subclone or a genetic variant of the previously identified Spanish epidemic clone C∶2b∶non-subtypable strains.

Meningitis neumocócica en niños españoles: incidencia, serotipos y resistencia antibiótica. Estudio prospectivo multicéntrico

Objetivo Conocer la incidencia, asi como los serotipos implicados y los patrones de resistencia antibiotica de meningitis producidas por Streptococcus pneumoniae en ninos espanoles. Material y metodo Estudio prosp ectivo, multicentrico, realizado en 5 comunidades autonomas (Cataluna, Galicia, Madrid, Navarra y Pais Vasco) a lo largo de 1 ano (1 de febrero de 2000 a 31 de enero de 2001). Se incluyeron todos los ninos entre 0 y 14 anos con meningitis neumococica diagnosticados por sintomatologia y liquido cefalorraquideo (LCR) sugerente con aislamiento de S. pneumoniae en LCR/sangre por metodos habituales o por tecnica de reaccion en cadena de la polimerasa (PCR), de la totalidad de hospitales de las comunidades autonomas estudiadas. La serotipia se realizo mediante la reaccion de quellung y/o immunoblotting y susceptibilidad a antibioticos por la tecnica de dilucion en agar. La poblacion infantil de 0–14 anos de estas comunidades es de 2.290.304 ninos. Resultados Se encontraron 52 casos. Uno tenia menos de 2meses de edad, 25 (48 %) entre 2 y 12 meses y 12 (23 %) entre 12 y 24 meses. La incidencia anual por 100.000 ninos en el primer y segundo ano de vida fue de 17,75 casos (intervalo de confianza [IC] al 95 %, 11,59–26,01) y 8,39 casos (IC 95 %, 4,67–15,79) respectivamente, siendo en los primeros 2 y 5 anos de vida de 13,13 (IC 95 %, 9,29–18,02) y 6,29 (IC 95 %, 4,57–8,45) casos, respectivamente. Casi la mitad de las cepas aisladas (47,6 %) mostraron sensibilidad disminuida a la penicilina. El serotipo 19F fue el mas frecuente (12 casos: 28,6%). El 80 % de los serotipos aislados estuvieron incluidos en la formulacion de la vacuna conjugada heptavalente. Conclusion La incidencia de meningitis neumococica en ninos de las 5 comunidades autonomas espanolas es elevada, casi el doble que la encontrada en un estudio previo de diseno retrospectivo, realizado en la misma poblacion 1–3 anos antes. Casi todos los serotipos aislados estan incluidos en la vacuna conjugada heptavalente. La mitad de las cepas mostraron sensibilidad disminuida a la penicilina.

Analysis of the Genetic Structure of Nontypeable Pneumococcal Strains Isolated from Conjunctiva

ABSTRACT More than 50% of the nontypeable (NT) pneumococcal strains received in our laboratory for reference purposes are isolated in sporadic cases of conjunctivitis. To determine the genetic structure of the population of these NT conjunctival strains, we analyzed 75 pneumococci (40 NT and 35 typeable) isolated from conjunctivas and 30 (15 NT and 15 typeable) isolated from other sources. The NT and typeable conjunctival strains grouped in separate clusters, whereas NT and typeable pneumococci isolated from other sources were similarly distributed. NT conjunctival strains belonged to two well-differentiated clonal lineages. The first, represented by three newly described sequence types, featured fully antibiotic susceptible strains and appeared to be characteristic of conjunctival tissue; the second, represented by the previously described ST344, had a pattern of multiresistance to penicillin, tetracycline, and erythromycin and shared a genetic background with some NT strains isolated from other sources.

Neisseria lactamica and Neisseria polysaccharea as possible sources of meningococcal beta-lactam resistance by genetic transformation.

We studied the susceptibilities of relatively penicillin G-resistant and -susceptible strains of Neisseria meningitidis, as well as Neisseria lactamica and Neisseria polysaccharea, to penicillin, ampicillin, and several cephalosporins. The MICs of penicillin, ampicillin, cephalothin, and cefuroxime for moderately resistant meningococci have increased two- to sixfold in relation to MICs for susceptible strains. For these strains of meningococci, N. lactamica, and N. polysaccharea, penicillin, ampicillin, cephalothin, and cefuroxime MICs for 50 and 90% of strains were similar. By genetic transformation of a penicillin-susceptible strain of N. meningitidis to low-level penicillin resistance with DNA from penicillin-resistant strains of N. meningitidis, N. lactamica, N. polysaccharea, and N. gonorrhoeae, isogenic strains with the same pattern of resistance to beta-lactams were obtained, suggesting that these commensal Neisseria spp. could be the source of meningococcal resistance genes.

The epidemic wave of meningococcal disease in Spain in 1996-1997: probably a consequence of strain displacement

During 1996 and 1997 an epidemic wave of meningococcal disease took place in Spain. Initial studies described the antigenic expression of the epidemic strain as C:2b:P1.2,5 and proposed that it was a variant of the previously identified Spanish C:2b:non-subtypable epidemic strain. To clarify this hypothesis, 1036 C:2b:P1.2(5) and 76 C:2b:NST isolates obtained during 1992-1999 were analysed by pulsed-field gel electrophoresis. The majority of the C:2b:P1.2,5 and C:2b:P1.2 isolates showed one of two very closely related profiles. During the epidemic period, 80% of the C:2b:NST strains showed these two pulsotypes. However, before the epidemic wave, most of these C:2b:NST strains (60%) showed a profile that was found infrequently among C:2b:P1.2,5 and C:2b:P1.2 isolates. A similar evolution was observed in C:2b:P1.5 isolates. Thirty-four C:2b:P1.2(5) and 10 C:2b:NST isolates, exhibiting representative pulsotypes, were subjected to multi-locus sequence typing. Isolates belonging to both A4 and ET-37 lineages were identified. These data point to the possibility that the A4 cluster has displaced the ET-37 complex among serogroup C meningococci in Spain.

In vitro susceptibilities of 400 Spanish isolates of Neisseria gonorrhoeae to gemifloxacin and 11 other antimicrobial agents.

ABSTRACT The in vitro activity of gemifloxacin versus those of 11 other antimicrobial agents against 400 strains of Neisseria gonorrhoeae was determined by microdilution with supplemented GC agar. A total of 37.5% of the strains were β-lactamase positive. A total of 70 and 6.4% of the β-lactamase-negative strains exhibited intermediate and high-level penicillin resistance, respectively. Ceftriaxone and gemifloxacin were the most active drugs (MICs at which 90% of isolates are inhibited, 0.01 versus 0.007 μg/ml, respectively), with 100% of strains inhibited by 0.12 μg/ml.

A modified scheme for biotyping Gardnerella vaginalis

A scheme is proposed for biotyping Gardnerella vaginalis, based on detection of hippurate hydrolysis, beta-galactosidase (ONPG) and lipase, and fermentation of arabinose, galactose and xylose. Seventeen biotypes were found among 197 strains from asymptomatic women and patients with bacterial vaginosis (non-specific vaginitis). The distribution of biotypes was similar in both populations but some biotypes were found more frequently in patients. The proposed scheme is compared with those previously described.

Multilocus sequence typing: el marcador molecular de la era de Internet

La epidemiologia global o a largo plazo tiene como objetivo el trazado preciso de los procesos de dispersion de lineas clonales, asociadas a altos niveles de virulencia, a determinada resistencia o a multirresistencia frente a uno o varios agentes antimicrobianos, etc. Por lo tanto, un sistema de tipificacion aplicado a este nivel, debe producir resultados que sean facilmente intercambiables entre laboratorios alejados geograficamente entre si, asi como detectar las diferentes lineas clonales incluso en presencia de bajos niveles de variabilidad acumulada en el genoma. Un marcador basado en secuencia de ADN puede producir unos resultados objetivos (secuencias de letras) que son facilmente almacenados en bases de datos accesibles mediante Internet. La aplicacion de una estrategia similar a la ya utilizada en el analisis de isoenzimas, con la secuenciacion de fragmentos variables de genes housekeeping seleccionados va a permitir obtener una vision global de la distribucion de los principales complejos clonales en la poblacion analizada, ademas de trazar su proceso de dispersion.