SUMMARY Surveillance studies have shown that OXA-48-like carbapenemases are the most common carbapenemases in Enterobacterales in certain regions of the world and are being introduced on a regular basis into regions of nonendemicity, where they are responsible for nosocomial outbreaks. OXA-48, OXA-181, OXA-232, OXA-204, OXA-162, and OXA-244, in that order, are the most common enzymes identified among the OXA-48-like carbapenemase group. OXA-48 is associated with different Tn1999 variants on IncL plasmids and is endemic in North Africa and the Middle East. OXA-162 and OXA-244 are derivatives of OXA-48 and are present in Europe. OXA-181 and OXA-232 are associated with ISEcp1, Tn2013 on ColE2, and IncX3 types of plasmids and are endemic in the Indian subcontinent (e.g., India, Bangladesh, Pakistan, and Sri Lanka) and certain sub-Saharan African countries. Overall, clonal dissemination plays a minor role in the spread of OXA-48-like carbapenemases, but certain high-risk clones (e.g., Klebsiella pneumoniae sequence type 147 [ST147], ST307, ST15, and ST14 and Escherichia coli ST38 and ST410) have been associated with the global dispersion of OXA-48, OXA-181, OXA-232, and OXA-204. Chromosomal integration of blaOXA-48 within Tn6237 occurred among E. coli ST38 isolates, especially in the United Kingdom. The detection of Enterobacterales with OXA-48-like enzymes using phenotypic methods has improved recently but remains challenging for clinical laboratories in regions of nonendemicity. Identification of the specific type of OXA-48-like enzyme requires sequencing of the corresponding genes. Bacteria (especially K. pneumoniae and E. coli) with blaOXA-48, blaOXA-181, and blaOXA-232 are emerging in different parts of the world and are most likely underreported due to problems with the laboratory detection of these enzymes. The medical community should be aware of the looming threat that is posed by bacteria with OXA-48-like carbapenemases.

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.

We performed whole-genome sequencing on 170 clinical carbapenemase-producing Enterobacter spp. isolates collected globally during 2008–2014. The most common carbapenemase was VIM, followed by New Delhi metallo-β-lactamase (NDM), Klebsiella pneumoniae carbapenemase, oxacillin 48, and IMP. The isolates were of predominantly 2 species (E. xiangfangensis and E. hormaechei subsp. steigerwaltii) and 4 global clones (sequence type [ST] 114, ST93, ST90, and ST78) with different clades within ST114 and ST90. Particular genetic structures surrounding carbapenemase genes were circulating locally in various institutions within the same or between different STs in Greece, Guatemala, Italy, Spain, Serbia, and Vietnam. We found a common NDM genetic structure (NDM-GE-U.S.), previously described on pNDM-U.S. from Klebsiella pneumoniae ATCC BAA-214, in 14 different clones obtained from 6 countries spanning 4 continents. Our study highlights the importance of surveillance programs using whole-genome sequencing in providing insight into the molecular epidemiology of carbapenemase-producing Enterobacter spp.

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.