Molecular characterization and antimicrobial susceptibility of Streptococcus pneumoniae isolated from children hospitalized with respiratory infections in Suzhou, China.

BACKGROUND: Dissemination of antibiotic resistant clones is recognized as an important factor in the emergence and prevalence of resistance in pneumococcus. This study was undertaken to survey the antimicrobial susceptibility and serotypes distribution of pneumococci and to explore the circulating clones in hospitalized children in Suzhou, China. METHODS: The pneumococci were isolated from the nasopharyngeal aspirates of children less than 5 years of age admitted to Soochow-University-Affiliated-Children's-Hospital with respiratory infections. The capsular serotypes were identified by multiplex polymerase chain reaction (PCR). Antimicrobial susceptibility was tested by E-test. The presence of ermB, mefA/E genes were detected by PCR and the genotypes were explored by Multilocus sequence typing (MLST). RESULTS: From July 2012 to July 2013, a total of 175 pneumococcal isolates were collected and all strains were resistant to erythromycin and clindamycin, about 39.4% strains were non-susceptible to penicillin G. Overall, 174 (99.4%) isolates were resistant to ≥ 3 types of antibiotics. Serotypes 19F (28.1%), 6B (19.7%), 19A (18.0%), and 23F (17.4%) were the most common serotypes in all identified strains. The serotypes coverage of PCV7 and PCV13 were 71.9% and 89.9%, respectively. Four international antibiotic-resistant clones, including Taiwan19F-14 (n = 79), Spain23F-1(n = 25), Taiwan23F-15(n = 7) and Spain6B-2(n = 7), were identified. The Taiwan19F-14 clones have a higher non-susceptibility rate in β-lactams than other clones and non-clone isolates (p<0.001). In addition, 98.7% Taiwan19F-14 clones were positive of both ermB and mefA/E genes, compare to 33.3% in other clones and non-clone strains. CONCLUSIONS: The spread of international antibiotic-resistant clones, especially Taiwan19F-14 clones, played a predominant role in the dissemination of antimicrobial resistant isolates in Suzhou, China. Considering the high prevalence of PCV7 serotypes and serotype 19A, the introduction of PCV13 may be a promising preventive strategy to control the increasing trend of clonal spread in China

Ca²⁺ Enhanced Nacre-Inspired Montmorillonite–Alginate Film with Superior Mechanical, Transparent, Fire Retardancy, and Shape Memory Properties

Inspired by nacre, this is the first time that using the cross-linking of alginate with Ca ions to fabricate organic–inorganic nacre-inspired films we have successfully prepared a new class of Ca²⁺ ion enhanced montmorillonite (MMT)–alginate (ALG) composites, realizing an optimum combination of high strength (∼280 MPa) and high toughness (∼7.2 MJ m^–3) compared with other MMT based artificial nacre. Furthermore, high temperature performance of the composites (with a maximum strength of ∼170 MPa at 100 °C) along with excellent transmittance, fire retardancy, and unique shape memory response to alcohols could greatly expand the application of the mutilfunctional composites, which are believed to show competitive advantages in transportion, construction, and insulations, protection of a flammable biological material, etc

Antimicrobial susceptibility and MICs of 175 <i>S.pneumoniae</i> strains isolated from respiratory infection Children younger than 5 years.

<p>Antimicrobial susceptibility and MICs of 175 <i>S.pneumoniae</i> strains isolated from respiratory infection Children younger than 5 years.</p

The antimicrobial susceptibility and MIC s of β-lactams antibiotics between international antibiotic-resistant clones and other strains.

<p>Note:</p>a<p>Clones represented the four international antibiotic-resistant clones including Taiwan^19F-14, Spain^23F-1, Taiwan^23F-15 and Spain^6B-2.</p

The serotype distribution of the <i>S.pneumoniae</i> isolates.

<p>Note: Given to 3 co-colonization isolates, the denominator of PCV coverage rate and serotype proportions was 178. NT indicated non-typed serotypes.</p

The demographic and clinical characteristics of 175 enrolled patients.

<p>Note:</p>a<p>Others included bronchitis, asthma, acute bronchiolitis and acute laryngotracheal bronchitis.</p

Population snapshot of 174 <i>S.pneumoniae</i> isolates.

<p>One spot represents a single ST. The size of the circle corresponds to the number of isolates belonging to a ST. The lines indicate the presence of single locus variant (SLV) links among particular STs. Blue spots indicate the founder of a clonal complex.</p

The distribution of macrolide-resistant genes among 175 <i>S.pneumoniae</i> isolates in different clones.

<p>Note:</p>a<p>The one isolates without ST number was grouped into other isolates.</p

The false positive rate of NTA test in control group children.

<p>Notes: NPS, nasopharyngeal swab; NTA, blind nasotracheal aspiration; ALRI, acute lower respiratory infection; CI, confidential interval.</p