Properties of Novel International Drug-Resistant Pneumococcal Clones Identified in Day-Care Centers of Lisbon, Portugal

Sousa, Natacha G.; Sá-Leão, Raquel; Crisóstomo, M. Inês; Simas, C.; Nunes, Sónia; Frazão, Nelson; Carriço, João André; Mato, R.; Sanches, Ilda Santos; Lencastre, Hermı́nia de

doi:10.1128/jcm.43.9.4696-4703.2005

Cited by 20 publications

(24 citation statements)

References 47 publications

(48 reference statements)

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“…Este fragmento de 340 Kb contiene los genes tetM y cat (2), que confieren resistencia a tetraciclina y cloranfenicol respectivamente, y que hacen parte del transposón conjugativo Tn5253 (19). La presencia de la banda puede explicarse por la inserción de este transposón en el genoma del neumococo, evento genético que puede alterar los sitios de restricción de la enzima Sma I y generar nuevos patrones electroforéticos (13,20).…”

Section: Resultsunclassified

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Caracterización molecular de aislamientos invasores colombianos de Streptococcus pneumoniae serotipo 5 recuperados entre 1994 y 2004.

2006

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Introducción. Streptococcus pneumoniae serotipo 5 es causa importante de enfermedad invasora en Colombia, donde se ha demostrado la circulación del clon 19-Colombia 5 susceptible a penicilina pero resistente a tetraciclina y a cloranfenicol. Objetivo. Establecer las relaciones genéticas de aislamientos invasores colombianos de S. pneumoniae serotipo 5 recuperados entre 1994 y 2004 con el clon 19-Colombia 5 . Materiales y métodos. Se estudiaron 83 aislamientos que tenían datos de susceptibilidad a penicilina, vancomicina, ceftriaxona, eritromicina, trimetoprim sulfametoxazol, cloranfenicol y tetraciclina, de los cuales 29 fueron obtenidos de niños menores de cinco años. El patrón de restricción del ADN se determinó por electroforesis en gel de campo pulsado, usando la enzima Sma I. La similitud genética entre los aislamientos y el clon se estableció según los criterios de Tenover y utilizando el programa Fingerprinting II. Resultados. Todos los aislamientos se relacionaron con el clon 19-Colombia 5 y se agruparon en el patrón electroforético A con 17 subtipos. El patrón A se estableció en 32 aislamientos (38,6%), el A8 en 18 (21,7%) y el A5 en 10 (12%), los 15 patrones restantes agruparon los otros 23 aislamientos. Los 34 aislamientos resistentes a tetraciclina y cloranfenicol mostraron relación con los patrones electroforéticos A (n = 32), A16 (n = 1) y A28 (n = 1), caracterizados, al igual que el clon, por presentar una banda de 340 Kb. Conclusión. Estos resultados muestran la circulación continua en el país de aislamientos de S. pneumoniae serotipo 5 genéticamente relacionados con el clon 19-Colombia 5 .Palabras clave: Streptococcus pneumoniae, meningitis, neumonía, electroforesis en gel de campo pulsado, resistencia a la tetraciclina, resistencia a cloranfenicol. Molecular characterization of Colombian invasive serotype 5 Streptococcus pneumoniae isolates recovered between 1994 and 2004Background. Streptococcus pneumoniae serotype 5 is an important cause of invasive disease in Colombia where the circulation of the clone Colombia 5 -19, penicillin susceptible but tetracycline and chloramphenicol resistant, has been demonstrated. Objective. To establish the genetic relatedness among Colombian invasive S. pneumoniae serotype 5 isolates, recovered between 1994 and 2004, and the clone Colombia 5 -19. Materials and methods. Eighty three isolates with penicillin, vancomycin, ceftriaxone, erythromycin, trimethoprim-sulfametoxazole, chloramphenicol and tetracycline susceptibility patterns were studied. Of these isolates, 29 were recovered from children less than 5 years of age. DNA restriction patterns of all isolates were determined for pulsed field gel electrophoresis, using the SmaI enzyme. Genetic similarity among isolates and the clone Colombia 5 -19 was established according to Tenover's criteria and the Fingerprintingä II program. Results. All isolates were related with the Colombia 5 -19 clone and belonged to the electrophoretic pattern A, of which 17 subtypes were derived. Most of the isolates belonged to pat...

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“…Estas características pueden hacer que la introducción de vacunas conjugadas lleve a la emergencia de nuevos clones resistentes que expresen serotipos no presentes en la vacuna (20).…”

Section: Resultsunclassified

Caracterización molecular de aislamientos invasores colombianos de Streptococcus pneumoniae serotipo 5 recuperados entre 1994 y 2004.

2006

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“…Antibioticresistant isolates obtained between 1996 and 2003 were characterized before (19,21,33,37). Isolates obtained in 2006 were partially described (according to their serotypes) before (29), and isolates obtained in 2007 are first described in this study.…”

Section: Methodsmentioning

confidence: 99%

“…PFGE patterns were analyzed with Bionumerics software (version 5; Applied Maths, Ghent, Belgium), and a dendrogram was generated using the Dice similarity coefficient with an optimization of 1.0% and a tolerance of 1.5%. PFGE clusters were defined by a similarity of 80% or higher on the dendrogram (4,37). Representatives of Pneumococcal Molecular Epidemiology Network (PMEN) clones were also used for comparison of molecular types (www.sph.emory.edu/PMEN).…”

Section: Methodsmentioning

confidence: 99%

Clonal Evolution Leading to Maintenance of Antibiotic Resistance Rates among Colonizing Pneumococci in the PCV7 Era in Portugal

et al. 2011

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The introduction of the seven-valent pneumococcal conjugate vaccine (PCV7) in Portugal led to extensive serotype replacement among carriers of pneumococci, with a marked decrease of PCV7 types. Although antimicrobial resistance was traditionally associated with PCV7 types, no significant changes in the rates of nonsusceptibility to penicillin, resistance to macrolides, or multidrug resistance were observed. This study aimed to investigate the mechanisms leading to maintenance of antimicrobial resistance, despite marked serotype replacement. We compared, through molecular typing, 252 antibiotic-resistant pneumococci recovered from young carriers in 2006 and 2007 (era of high PCV7 uptake) with collections of isolates from 2002 and 2003 (n ‫؍‬ 374; low-PCV7-uptake era) and 1996 to 2001 (n ‫؍‬ 805; pre-PCV7 era). We observed that the group of clones that has accounted for antimicrobial resistance since 1996 is essentially the same as the one identified in the PCV7 era. The relative proportions of such clones have, however, evolved substantially overtime. Notably, widespread use of PCV7 led to an expansion of two Pneumococcal Molecular Epidemiology Network (PMEN) clones expressing non-PCV7 capsular variants of the original strains: Sweden 15A ST63 (serotypes 15A and 19A) and Denmark 14 ST230 (serotypes 19A and 24F). These variants were already in circulation in the pre-PCV7 era, although they have now become increasingly abundant. Emergence of novel clones and de novo acquisition of resistance contributed little to the observed scenario. No evidence of capsular switch events occurring after PCV7 introduction was found. In the era of PCVs, antimicrobial resistance remains a problem among the carried pneumococci. Continuous surveillance is warranted to evaluate serotype and clonal shifts leading to maintenance of antimicrobial resistance.Streptococcus pneumoniae is a Gram-positive bacterium that frequently colonizes asymptomatically the nasopharynx of young children. However, it is also an important human pathogen that can cause a wide range of diseases, from otitis media to pneumonia and meningitis. Worldwide, it has been estimated that 14.5 million episodes of serious pneumococcal disease and 826,000 deaths per year occur in children aged less than 5 years (23).In 2000, a seven-valent pneumococcal conjugate vaccine (PCV7) targeting the seven most common serotypes (4, 6B, 9V, 14, 18C, 19F, and 23F) causing invasive disease among young children in the United States became available. Since then, in countries where the vaccine has been introduced in the universal vaccination plan, a dramatic reduction in the incidence of invasive disease caused by PCV7 serotypes has been observed in all age groups (11,17,35). This extended phenomenon beyond the target group, known as herd immunity, has been attributed to decreased transmission of pneumococci from children to other age groups. Indeed, the nasopharynx of children is the main reservoir of pneumococci, and a decrease in carriage of PCV7 serotypes has been observed in vaccina...

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“…PFGE patterns were compared with patterns of serotypable pneumococcal strains isolated between 1996 and 2003 in the same settings (Nunes et al, 2005;Sá-Leão et al, 2000b;Sousa et al, 2005) PFGE letter assignments were given arbitrarily, and two or three capital letters were assigned to each PFGE clone. If a clone had been identified in a previous study, the same letter assignment was maintained to enable direct comparison with previous publications.…”

Section: Methodsmentioning

confidence: 99%

Identification, prevalence and population structure of non-typable Streptococcus pneumoniae in carriage samples isolated from preschoolers attending day-care centres

et al. 2006

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The authors aimed to get insights into the population structure of non-(sero)typable pneumococci (NTPn), a specific group of natural atypical pneumococci whose identification is often difficult, and which has remained insufficiently studied. A total of 265 presumptive NTPn, isolated between 1997 and 2003 from the nasopharynx of children, were characterized. Strains were confirmed to be pneumococci on the basis of bile solubility, and PCR detection or Southern blotting hybridization of lytA and psaA, genes ubiquitous in this species. Multilocus sequence typing (MLST) was used to exclude two isolates that gave ambiguous results. Non-typability was confirmed by the Quellung reaction using Omniserum. A total of 213 isolates were considered to be true NTPn. The molecular analysis of the true NTPn by PFGE and MLST showed that this population was genetically diverse, although a dominant cluster, accounting for 66 % of the isolates, was identified. Antimicrobial resistance was observed in most genetic backgrounds, and multidrug resistance to penicillin, erythromycin, clindamycin, tetracycline and sulfamethoxazole-trimethoprim was associated with strains belonging to the dominant cluster. Comparison with PFGE fingerprints and sequence types of large collections of serotypable strains showed that the genetic backgrounds of all but two NTPn were different from those found in serotypable strains. In addition, we found that NTPn strains with similar genetic backgrounds to those identified in our study had been isolated from disease sources in other countries. These observations seem to indicate that NTPn have diverse genetic backgrounds and may have evolved as a distinct group of pneumococcal isolates. INTRODUCTIONStreptococcus pneumoniae is a respiratory pathogen that colonizes asymptomatically the nasopharynx of humans. Although the mortality and morbidity associated with pneumococci are high, they are considered to be facultative pathogens: colonization is the rule, and disease the exception (Centers for Disease Control and Prevention, 2000).Most pneumococci are shielded by a polysaccharide capsule, a major virulence factor that hinders phagocytosis. Up to now, at least 90 different capsular types have been described (Henrichsen, 1995). The capsule can be detected by reaction with specific antisera. However, although some isolates are presumptively identified as pneumococci by routine identification tests, a negative result with type-specific antisera for the 90 serotypes is obtained. These atypical isolates are designated non-typable pneumococci (NTPn), and their correct discrimination from commensal viridans streptococci is often difficult (Carvalho et al., 2003;Hanage et al., 2005;Shayegani et al., 1982;Whatmore et al., 2000). The distinction between these closely related species is clinically important, since S. pneumoniae can cause serious disease and viridans streptococci are commensal organisms. Some NTPn have been described as extremely contagious and have been associated with pneumococcal conjunctivitis, causing ...

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Properties of Novel International Drug-Resistant Pneumococcal Clones Identified in Day-Care Centers of Lisbon, Portugal

Cited by 20 publications

References 47 publications

Caracterización molecular de aislamientos invasores colombianos de Streptococcus pneumoniae serotipo 5 recuperados entre 1994 y 2004.

Caracterización molecular de aislamientos invasores colombianos de Streptococcus pneumoniae serotipo 5 recuperados entre 1994 y 2004.

Clonal Evolution Leading to Maintenance of Antibiotic Resistance Rates among Colonizing Pneumococci in the PCV7 Era in Portugal

Identification, prevalence and population structure of non-typable Streptococcus pneumoniae in carriage samples isolated from preschoolers attending day-care centres

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