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This study investigated 248 extended-spectrum β-lactamase-producing Escherichia coli isolates from 2012 to 2013 for hybrid bla CTX-M genes. bla CTX-M genes were detected in 228 isolates of which 14 isolates were hybrid bla CTX-M positive (6 bla CTX-M-123 , 6 bla CTX-M-64 , and 2 bla CTX-M-132 ). The 14 hybrid bla CTX-M –carrying isolates (8 from chickens, 2 each from pigs and cattle, 1 each from dog and rodent) were genetically diverse. All but 2 hybrid bla CTX-M were carried on IncI1 (5 bla CTX-M-123 ) and IncI2 (6 bla CTX-M-64 and one bla CTX-M-132 ) plasmids. Our IncI1 and IncI2 plasmids had pHNAH4-1–like and pHN1122-1–like restriction fragment length polymorphism patterns, respectively. Genetic relatedness of the plasmids to pHNAH4-1 and pHN1122-1 were confirmed by complete sequencing of 3 plasmids, pCTXM123_C0996, pCTXM64_C0967, and pCTXM132_P0421. Plasmids closely related to pHNAH4-1 and pHN1122-1 and carrying different bla CTX-M alleles have been reported from multiple geographic areas in China previously. The findings highlighted the wide dissemination of hybrid bla CTX-M variants in different parts of China. [ABSTRACT FROM AUTHOR]

We collected nasal, axilla, and groin swabs from 252 adult patients from 2 nephrology centers in Hong Kong. Staphylococcus lugdunensis carriage was detected in 51.6% patients (groin, 39.3%; axilla, 19.8%; nose, 17.9%). The carriage rates of methicillin-sensitive S . lugdunensis and methicillin-resistant S . lugdunensis (MRSL) were 46.0% and 8.3%, respectively. Independent risk factors for S . lugdunensis carriage included male sex (odds ratio [OR], 4.4), hemodialysis (OR, 2.2), and aged 18–50 years (OR, 2.4). The isolates belonged to 10 pulsotype clusters (n = 129) and 8 singletons (n = 8). All MRSL and most gentamicin- and tetracycline-resistant strains were found in a predominating sequence type 3 clone, designated HKU1, which accounted for 51.8% of all colonizing S . lugdunensis strains. The 21 MRSL isolates had SCC mec type V (n = 18), type IV (n = 2), and type I (n = 1). The finding highlights the potential for dissemination of multidrug resistance through successful S . lugdunensis clones. [ABSTRACT FROM AUTHOR]

Abstract: This study assessed the susceptibility trend of methicillin-resistant Staphylococcus aureus (MRSA) in 5 Hong Kong hospitals from 1995 to 2005. Representative blood isolates were characterized to correlate the changes in resistance phenotypes with the clonal nature of MRSA. The prevalence of multisusceptible (MS) MRSA, defined by sensitivity to gentamicin, co-trimoxazole, and fusidic acid, was found to increase dramatically from <2% in 1995 to 1997 to 4.5% to 5.8% in 1998 to 1999 and remained at around 10% thereafter. Isolation of MS-MRSA was significantly associated with older age, convalescent care, and blood culture source. Molecular typing showed that the increasing isolation of MS-MRSA was associated with the spread of ST45/Staphylococcus cassette chromosome mec (SCCmec) IV or V with spa t1768, t1857, or t1081. Other features of the ST45 strains are as follows: agr4, capsular type 8, and Panton–Valentine leukocidin (PVL) negative. Two other epidemic clones, EMRSA-16 (ST36/SCCmec II) and CC398 (ST1277/SCCmec V), were detected as sporadic isolates for the first time in Hong Kong. [Copyright &y& Elsevier]

Abstract: This prospective study assessed the epidemiology of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) among patients with purulent skin and soft tissue infections (SSTIs) in Hong Kong. Among 298 patients with SSTIs, 10.4% (13/125) of all S. aureus isolates and 5% (12/241) of all abscesses were attributed to pvl-positive CA-MRSA. Overall, 77% and 69.9% of CA-MRSA and methicillin-sensitive S. aureus (MSSA) were susceptible to erythromycin, 77% and 74.8% to clindamycin, 100% and 97.1% to minocycline, and 100% and 98.1% to rifampin, respectively. Filipino ethnicity was the only clinical and epidemiologic factor significantly associated with CA-MRSA infection (odds ratio, 14.8; 95% confidence interval, 3.3–70.0; P < 0.001). Pulsed-field gel electrophoresis analysis showed that 6 CA-MRSA isolates belonged to the ST30-HKU100 clone, 5 belonged to the ST59-HKU200 clone, and 1 was singleton. Features of HKU100 isolates include SCCmec type IV, agr3, spa t019, and pan-susceptibility to non–β-lactam antibiotics. In contrast, HKU200 isolates are characterized by having SCCmec type IV or V, agr4, spa t437, and variable non–β-lactam susceptibility profiles. The major CA-MRSA spa types were shared by a minority of the MSSA. [Copyright &y& Elsevier]

The emergence and rapid spread of the mobile colistin resistance gene mcr-1 among bacterial species and hosts significantly challenge the efficacy of "last-line" antibiotic colistin. Previously, we reported silver nitrate and auranofin serve as colistin adjuvants for combating mcr-1-positive bacteria. Herein, we uncovered more gold-based drugs and nanoparticles, and found that they exhibited varying degree of synergisms with colistin on killing mcr-1-positive bacteria. However, pre-activation of the drugs by either glutathione or N-acetyl cysteine, thus releasing and accumulating gold ions, is perquisite for their abilities to substitute zinc cofactor from MCR-1 enzyme. X-ray crystallography and biophysical studies further supported the proposed mechanism. This study not only provides basis for combining gold-based drugs and colistin for combating mcr-1-positive bacterial infections, but also undoubtedly opens a new horizon for metabolism details of gold-based drugs in overcoming antimicrobial resistance. [ABSTRACT FROM AUTHOR]