Increased extended-spectrum β-lactamase–producing E. coli in Japan resulted mainly from a clade containing this gene.

This Japanese regional ESBL-producing E. coli epidemic is closely associated with newly identified CTX-M-27- and CTX-M-14-producing ST131 H30R subclonal groups and with mobile elements IS26, ISEcp1 and IS903D.

Escherichia coli sequence type 131 (ST131) is a pandemic clonal lineage that is responsible for the global increase in fluoroquinolone resistance and extendedspectrum-␤-lactamase (ESBL) producers. The members of ST131 clade C, especially subclades C2 and C1-M27, are associated with ESBLs. We developed a multiplex conventional PCR assay with the ability to detect all ST131 clades (A, B, and C), as well as C subclades (C1-M27, C1-nM27 [C1-non-M27], and C2). To validate the assay, we used 80 ST131 global isolates that had been fully sequenced. We then used the assay to define the prevalence of each clade in two Japanese collections consisting of 460 ESBL-producing E. coli ST131 (2001-12) and 329 E. coli isolates from extraintestinal sites (ExPEC) (2014). The assay correctly identified the different clades in all 80 global isolates: clades A (n ϭ 12), B (n ϭ 12), and C, including subclades C1-M27 (n ϭ 16), C1-nM27 (n ϭ 20), C2 (n ϭ 17), and other C (n ϭ 3). The assay also detected all 565 ST131 isolates in both collections without any false positives. Isolates from clades A (n ϭ 54), B (n ϭ 23), and C (n ϭ 483) corresponded to the O serotypes and the fimH types of O16-H41, O25b-H22, and O25b-H30, respectively. Of the 483 clade C isolates, C1-M27 was the most common subclade (36%), followed by C1-nM27 (32%) and C2 (15%). The C1-M27 subclade with bla CTX-M-27 became especially prominent after 2009. Our novel multiplex PCR assay revealed the predominance of the C1-M27 subclade in recent Japanese ESBL-producing E. coli isolates and is a promising tool for epidemiological studies of ST131.

Pneumococcal infection in children is a major public health problem worldwide, including in Japan. The pneumococcal conjugate vaccine 7 (PCV7) was licensed for use in Japan in 2010 followed by PCV13 in 2013. This report includes the results of a nationwide surveillance of invasive pneumococcal disease (IPD) and non-IPD in paediatric patients from January 2012 to December 2014. We collected 343 isolates from 337 IPD patients and 286 isolates from 278 non-IPD patients. Of the IPD isolates, the most identified serotypes included 19A, 24F, and 15A. The prevalence of non-PCV13 serotype isolates increased significantly from 2012 to 2014 (51.6-71.4%, p=0.004). Serotypes 19A, 15A and 35B were highly non-susceptible to penicillin, and the rates of non-susceptible isolates from IPD patients to penicillin and cefotaxime significantly declined during the study period (p=0.029 and p=0.013, respectively). The non-susceptible rate to meropenem increased, particularly for serotype 15A. The IPD isolates comprised clonal complex (CC) 3111 (93.8% was serotype 19A) followed by CC2572 (81.5% was serotype 24F) and CC63 (97.1% was serotype 15A). CC3111, CC63 and CC156 (33.3% was serotype 23A, 28.6% was serotype 6B, and 14.3% was serotype 19A) were highly non-susceptible to penicillin. Of the non-IPD isolates, the most identified serotypes included 19A, 15A, and 3. In conclusion, the introduction of PCV7 and PCV13 resulted in increasing non-PCV13 serotypes and clones, including antimicrobial resistant serotypes 15A and CC63 (Sweden(15A)-25 clone).

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