Antimicrobial susceptibility and pneumococcal serotypes

Abstract

The increase in antibiotic resistance and the possible changes in serotype prevalence as a consequence of a new conjugated vaccine have contributed to renewed interest in the study of pneumococcal serotypes and their antibiotic resistances. Spain still has one of the highest penicillin resistance rates, but in the past 4-5 years a slight decrease has been observed. The level of resistance has not increased either, 12.7% of the 11 165 isolates studied showed high-level penicillin resistance but 94% of these had an MIC of only 2 mg/L. Serotypes 6, 9, 14, 19 and 23 included 83% of the penicillin-resistant pneumococci; the remaining 17% belonged to 18 different serotypes. We analysed these minor penicillin-resistant serotypes in view of their potential increase following a possible child vaccination programme. Four of these serotypes (11, 15, 21 and 35) were the most prevalent, and among them serotype 15 was particularly frequent with >50% of its strains resistant. The effective control of these minor penicillin-resistant serotypes should be based on continuous surveillance of pneumococcal epidemiology.

Population Structure, Antimicrobial Resistance, and Mutation Frequencies of Streptococcus pneumoniae Isolates from Cystic Fibrosis Patients

“…Data about the antibiotic resistance of S. pneumoniae strains isolated from CF patients remain scarce (7). Our CF pneumococcal pediatric isolates were unusually nonsusceptible to antibiotics, if they are compared with those isolated from non-CF patients (11,28), particularly to penicillin (75% versus 48.5%) and cefotaxime (33% versus 6.2%). We have previously reported similar differences for oropharyngeal streptococci belonging to the viridans group, which are significantly more resistant to penicillin and cefotaxime in CF patients than those of healthy children (2).…”

“…The international clone Spain 23F -1 uniformly shows resistance to penicillin, tetracycline, chloramphenicol, and trimethoprim-sulfamethoxazole (11). Among the clone A isolates, this resistance pattern was detected in two out of three isolates; other isolates also showed resistance to cefotaxime.…”

Streptococcus pneumoniae: evolución de los serotipos y los patrones de susceptibilidad antimicrobiana en aislamientos invasores en 11 años de vigilancia en colombia (1994 -2004).

“…En general, los serotipos resistentes a los antibióticos en Colombia son los mismos reconocidos universalmente, pero con diferente prevalencia (31). Particular énfasis se le ha dado al estudio de la evolución de la resistencia a la penicilina, la cual, como ha ocurrido en muchas partes del mundo, se ha incrementado durante los años de vigilancia (8,11,32).…”

“…Los niveles de resistencia a eritromicina fueron bajos (3,8%) y contrastan con muchos informes en los cuales se documentan altos niveles de resistencia a macrólidos (11,36); sin embargo, es importante tener en cuenta que se ha evidenciado que en los países en donde existe un alto consumo de macrólidos se puede dar un rápido incremento de aislamientos resistentes a esta familia de antibióticos (31). De igual forma, la resistencia a levofloxacina es baja (1,5%); esta fluoroquinolona de amplio espectro ha surgido como una alternativa terapéutica para la neumonía causada por S. pneumoniae en adultos; sin embargo, no se recomienda como primera opción, sino que debería reservarse para pacientes con infecciones causadas por aislamientos resistentes a otros antibióticos y pacientes alérgicos a B-lactámicos (37).…”

Emergence of a Unique Penicillin-Resistant Streptococcus pneumoniae Serogroup 35 Strain

“…Serogroups/types (SGTs) 6, 9, 14, 19, and 23 are the most common SGTs associated with penicillin resistance in the United States (15,39). PNSP strains of other SGTs have been recognized worldwide, especially serotype 35B (7,15,21,25,28,29).…”