Clonality behind the increase of multidrug-resistance among non-invasive pneumococci in Southern Finland

Abstract

Multidrug-resistance among Streptococcus pneumoniae isolates, especially of serotype 19A, has increased in several countries recently. Even before the introduction of the pneumococcal conjugate vaccine into the Finnish National Vaccination Programme, the proportion of multidrug-resistant (MDR) pneumococci had doubled from 2007 to 2008, when it reached 3.6% in Southern Finland. Our aim was to look for a possible association between antimicrobial susceptibility and clonality among the MDR isolates. Twelve non-invasive isolates non-susceptible to penicillin, erythromycin, clindamycin, trimethoprim/sulfamethoxazole, and doxycycline from 2008 were available for serotyping, genotyping by multilocus sequence typing (MLST), and detection of genes encoding macrolide resistance and adherence-promoting pili. Two isolates were also resistant to ceftriaxone. Five serotypes, 19F, 19A, 6B, 23F, and 14, and six genotypes from three genetic lineages were found, among which CC320 was the largest. All isolates in this study carried the erm(B) macrolide resistance gene, and the CC320 isolates additionally carried the mef(A/E) macrolide resistance gene. Eleven isolates carried pilus islet 1, while the CC320 isolates also carried the pilus islet 2 genes. The findings emphasize the importance of the careful monitoring of antimicrobial susceptibility and serotype distribution among pneumococci, especially now that antimicrobials and pneumococcal vaccines are in widespread use.

Microbiological characterization of Streptococcus pneumoniae and non-typeable Haemophilus influenzae isolates as primary causes of acute otitis media in Bulgarian children before the introduction of conjugate vaccines

“…A considerable increase in the disease caused by serotype 19A has been recorded after the introduction of PCV7 in some countries [24,26]. Of note, MDR serotype 19A isolates have also been identified in Israel and Finland before the large-scale use of conjugate vaccines as was the case in our study [27,28]. …”

Molecular Epidemiology of Streptococcus pneumoniae Isolates from Children with Recurrent Upper Respiratory Tract Infections

“…Many studies have revealed that worldwide pneumococcal diseases are mostly caused by a few multidrug-resistant clones [ 11 , 12 , 13 , 14 ]. The aim of this study was to seek for the clonality among the pneumococcal strains detected in preschool children with recurrent upper respiratory tract infections (URTIs), based on the analysis of serotypes, antimicrobial susceptibility patterns and genotypic characteristics, including the transposons with resistance genes and clonality of the pneumococcal isolates performed by multilocus sequence typing (MLST) method.…”

Molecular Characterization and Antimicrobial Susceptibility of Streptococcus pneumoniae Isolated from Children Hospitalized with Respiratory Infections in Suzhou, China

“…In 2005, the World Health Organization (WHO) estimated that 0.7–1 million children, mostly from developing countries, died of pneumococcal disease annually [1]. The increasing trend of S.pneumoniae antimicrobial-resistance and emergence of multidrug- resistant (MDR) S.pneumoniae isolates, which may result from inappropriate use of antibiotics, has been a worldwide concern [2], [3], [4], [5]. The situation has been especially problematic in many Asian countries, China in particular.…”