Pediatr Infect Dis J. 2015 Nov 18. [Epub ahead of print]

Vaccine Serotypes of Streptococcus pneumoniae with High-Level Antibiotic Resistance Isolated More Frequently 7 Years After the Licensure of PCV7 in Beijing.

Lyu S1, Yao KH, Dong F, Xu BP, Liu G, Wang Q, Shi W, Tong JJ, Shen KL, Yang YH.

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Abstract

BACKGROUND:

Streptococcus pneumoniae 7-valent conjugate vaccine (PCV7) was made available in China in the private sector in September 2008.

METHOD:

The present study investigated the serotype distribution, antibiotic resistance, and molecular characteristics of S. pneumoniae in hospitalized pediatric patients. Pneumococcal isolates were collected from hospitalized children under 14 years of age. Their serotypes were determined using Quellung reactions with antisera; antibiotic resistance against 13 antimicrobials was tested using the E-test method or disc diffusion. The sequence types (STs) were analyzed with multilocus sequence typing (MLST).

RESULTS:

A total of 187 pneumococcal specimens were collected, including 21 invasive and 166 non-invasive isolates. The prevailing serotypes were 19F (31.6%), 19A (19.8%), 23F (11.2%), 6A (9.1%), 14 (9.1%) and 15B (5.9%). The coverage rates of PCV7, PCV10 and PCV13 were 56.2% (105/187), 56.7% (106/187) and 86.1% (161/187), respectively. The overall non-susceptibility rate against penicillin was 8.0%; however, this rate would have been 91.5% if based on an oral breakpoint. All but one of the isolates were highly resistant to erythromycin. Multi-drug resistance (MDR) was exhibited by 177 (94.7%) isolates. The five predominant MLSTs for all pneumococci were ST271 (24.1%), ST320 (18.2%), ST81 (7.5%), ST876 (7%) and ST3397 (5.3%), which were primarily related to serotypes 19F, 19A, 23F, 14, and 15B, respectively. CC271 was the most frequent antibiotic-resistant complex clone (CC).

CONCLUSIONS:

The coverage rates of PCVs were high, and the antibiotic resistance rates were of serious concern among hospitalized children. Universal immunization using PCVs would likely prevent episodes of S. pneumoniae diseases and the spread of antibiotic resistance in Beijing.

PMID: 26584056 [PubMed - as supplied by publisher]