Resistance Determinants and Their Association with Different Transposons in the Antibiotic-ResistantStreptococcus pneumoniae

Abstract

Multiple resistance of Streptococcus pneumoniae is generally associated with their unique recombination-mediated genetic plasticity and possessing the mobile genetic elements. The aim of our study was to detect antibiotic resistance determinants and conjugative transposons in 138 antibiotic-resistant pneumococcal strains isolated from nasopharynx of healthy young children from Lublin, Poland. These strains resistant to tetracycline and/or to chloramphenicol/erythromycin/clindamycin were tested by PCR using the specific genes as markers. The presence of Tn916 family transposons, carrying tet(M) and int/xisTn916, was observed in all of the tested strains. Tn916 was detected in 16 strains resistant only to tetracycline. Tn6002 and Tn3872-related element were found among 99 erm(B)-carrying strains (83.8% and 3.0%, resp.). Eight strains harbouring mef(E) and erm(B) genes were detected, suggesting the presence of Tn2010 and Tn2017 transposons. Among 101 chloramphenicol-resistant strains, two variants of Tn5252-related transposon were distinguished depending on the presence of int/xis5252 genes specific for cat gene-containing Tn5252 (75.2% of strains) or int Sp23FST81 gene, specific for cat-containing ICESp23FST81 element (24.8% of strains). In 6 strains Tn916-like and Tn5252-like elements formed a Tn5253-like structure. Besides clonal dissemination of resistant strains of pneumococci in the population, horizontal transfer of conjugative transposons is an important factor of the high prevalence of antibiotic resistance.

Determination of Characteristics of Erythromycin Resistant Streptococcus pneumoniae with Preferred PCV Usage in Iran

“…Double resistant genes were present in 32% of our isolates which was significantly higher than some other investigators [20]. The prevalence of dual resistance genes in the pneumococcal isolates amongst the macrolide resistant isolates has been reported around 16% globally [17, 21] and up to 63% in China in recent years [22]. …”

“…On the contrary, efflux mediated pump gene ( mef ), which has been reported to be the dominant macrolide resistant in North American countries [17–18] and Germany [19], was found only in 20% of our isolates. Double resistant genes were present in 32% of our isolates which was significantly higher than some other investigators [20].…”

New Insights into the Classification and Integration Specificity of Streptococcus Integrative Conjugative Elements through Extensive Genome Exploration

“…All of them carry at least one ICE/dICE suggesting a possible correlation between the presence of ICEs and resistance to antibiotics. Indeed among the families detected, Tn 916 ( Roberts and Mullany, 2011 ), Tn 5252 ( Korona-Glowniak et al, 2015 ), and Tn 1549 ( Garnier et al, 2000 ) are known vectors of antibiotic resistance genes.…”

Community-Acquired Pneumonia in Children Caused by Pneumococci of MLSB- and M-Phenotype: Clinical Cases

“…S. pneumoniae -основной возбудитель внебольничной пневмонии -во всем мире демонстрирует рост устойчи-вости к макролидам и родственным антибиотикам (лин-козамидам и стрептограмину) [16]. Резистентность к дан-ным группам препаратов обусловлена двумя основными механизмами -модификацией мишени действия анти-биотика (рибосом) и эффлюксом (активным выведением антибиотика из клетки) [17,18]. Рибосомальные изме-нения обусловлены метилтрансферазой, кодируемой геном ermB, которая метилирует остаток А2058 домена V 23S-РНК; в результате формируется так называемый MLSB-фенотип (перекрестная устойчивость к макро-лидам, линкозамидам и стрептограмину В).…”

“…Это связа-но с инсерцией (вставкой) гена ermB в конъюгативные и композитные транспозоны семейства Tn916, несущие ген tetM, кодирующий протеины «защиты рибосом» [18].…”