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Six imported pigs originating from Guangdong, Henan, and Hunan provinces in China during October 2015 to February 2017 were cultured and found to be positive for meropenem-resistant Escherichia coli The samples yielded 9 E. coli isolates of diverse sequence types carrying bla NDM-5 on IncX3 (8 isolates from 5 farms) or IncFII (1 isolate from 1 farm) plasmids. The mcr-1 gene was coharbored by 4 isolates. The IncX3 plasmids (∼46 kb) carrying bla NDM-5 were identical or nearly identical to each other., (Copyright © 2018 American Society for Microbiology.)

Of 137 Staphylococcus lugdunensis isolates collected from two nephrology centers in Hong Kong, 10 (7.3%) and 3 (2.2%) isolates had high-level and low-level mupirocin resistance, respectively. Isolates with high-level resistance contained the plasmid-mediated ileS2 gene, while isolates with low-level resistance contained the mutation V588F within the chromosomal ileS gene. All but one of the ileS2-positive isolates belong to the predominating clone HKU1. Plasmids carrying the ileS2 gene were mosaic and also cocarry multiple other resistance determinants., (Copyright © 2016, American Society for Microbiology. All Rights Reserved.)

Increasing consumption of nitrofurantoin (NIT) for treatment of acute uncomplicated urinary tract infections (UTI) highlights the need to monitor emerging NIT resistance mechanisms. This study investigated the molecular epidemiology of the multidrug-resistant efflux gene oqxAB and its contribution to nitrofurantoin resistance by using Escherichia coli isolates originating from patients with UTI (n = 205; collected in 2004 to 2013) and food-producing animals (n = 136; collected in 2012 to 2013) in Hong Kong. The oqxAB gene was highly prevalent among NIT-intermediate (11.5% to 45.5%) and -resistant (39.2% to 65.5%) isolates but rare (0% to 1.7%) among NIT-susceptible (NIT-S) isolates. In our isolates, the oqxAB gene was associated with IS26 and was carried by plasmids of diverse replicon types. Multilocus sequence typing revealed that the clones of oqxAB-positive E. coli were diverse. The combination of oqxAB and nfsA mutations was found to be sufficient for high-level NIT resistance. Curing of oqxAB-carrying plasmids from 20 NIT-intermediate/resistant UTI isolates markedly reduced the geometric mean MIC of NIT from 168.9 μg/ml to 34.3 μg/ml. In the plasmid-cured variants, 20% (1/5) of isolates with nfsA mutations were NIT-S, while 80% (12/15) of isolates without nfsA mutations were NIT-S (P = 0.015). The presence of plasmid-based oqxAB increased the mutation prevention concentration of NIT from 128 μg/ml to 256 μg/ml and facilitated the development of clinically important levels of nitrofurantoin resistance. In conclusion, plasmid-mediated oqxAB is an important nitrofurantoin resistance mechanism. There is a great need to monitor the dissemination of this transferable multidrug-resistant efflux pump., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)

The MICs of 17 antimicrobial agents for 181 Streptococcus pneumoniae strains were determined by the E-test. Overall, 69.1% were penicillin resistant (MIC > 0.06 microgram/ml). Resistance to ciprofloxacin (MIC > 2 microgram/ml), levofloxacin (MIC > 2 microgram/ml), or trovafloxacin (MIC > 1 microgram/ml) was found in 12.1, 5.5, or 2.2% of the strains, respectively. These high rates of resistance raise concerns for the future.