word count 250) Background: To describe the infection control preparedness for Coronavirus Disease (COVID-19) due to SARS-CoV-2 [previously known as 2019-novel coronavirus] in the first 42 days after announcement of a cluster of pneumonia in China, on 31 December 2019 (day 1) in Hong Kong. Methods:A bundle approach of active and enhanced laboratory surveillance, early airborne infection isolation, rapid molecular diagnostic testing, and contact tracing for healthcare workers (HCWs) with unprotected exposure in the hospitals was implemented.Epidemiological characteristics of confirmed cases, environmental and air samples were collected and analyzed.

Here we report the synthesis of vancomycin (Van)-capped Au nanoparticles (Au@Van) and their enhanced in vitro antibacterial activities. Au@Van presumably acts as a rigid polyvalent inhibitor of vancomycin-resistant enterococci (VRE). It also has unexpected activity against an E. coli strain. Our results suggest that gold nanoparticles may serve as a useful model system to explore multi/polyvalent interactions of ligand−receptor pairs.

Covalently linked to vancomycin (Van), chemically stable and highly magnetic anisotropic FePt magnetic nanoparticles (3-4 nm) become water-soluble and capture vancomycin-resistant enterococci (VRE) and other Gram-positive bacteria at concentrations approximately 10(1) cfu/mL via polyvalent ligand-receptor interactions. When a pyramidal end of a magnet "focuses" the nanoparticles into approximately 1 mm(2) area, the bacteria can be observed by an optical microscope and further identified by electron micrograph (EM). Compared to the conventional use of magnetic particles (with the sizes of 1-5 microm) in biological separation or drug delivery, magnetic nanoparticles, combined with specific receptor-ligand interactions, promise a sensitive and rapid protocol to detect pathogens.

This paper reports the first antibiotic gelatorsvancomycin-pyrene (1)sthat forms hydrogels via hydrophobic interaction and hydrogenbonding-promoted self-assembly in water. Hydrogels, formed by three-dimensional, elastic networks whose interstitial spaces are filled with water, present many useful properties (e.g., response to the external stimuli) and applications (e.g., gel electrophoresis, chemical sensing, drug delivery, as a biointerface, and as actuators). 1,2 Biopolymers (e.g., collagens, 3 polysaccharide, 4 etc.) and hydrophilic synthetic polymers (e.g., polyacrylamide 2,5 and polypeptides 6 ) have been successfully employed to form hydrogels. Nonpolymeric hydrogelators, however, are rare despite that their counterpartsssmall molecular organogelators 7,8 shave expanded rapidly and received intensive studies in the past decade. Recently, Hamilton, 9 Shinkai, 10 Zhang, 11 and others 12 have reported low molecular weight hydrogelators that form hydrogels via carefully balancing the hydrophobic interactions and hydrogen bonds in water to induce aggregations of those small molecules. Their results inspired us to design and synthesize hydrogelators based on antibioticssan important class of biomoleculessin the hope of developing biomaterials that can treat infectious wounds, serve as an antiseptic matrix, and provide a new way of drug delivery. 13 We chose vancomycin (Van), one of the most important antibiotics, as the platform to make the hydrogelators because of (1) its clinical significance in treating Gram-positive bacterial infections; 14 (2) its relatively easy synthetic modifications; 15 and (3) its strong tendency to form multiple hydrogen bonds with suitable substrates or itself in aqueous solution, as revealed by Wash et al. in the decipherment of the molecular logic of vancomycin resistance enterococci (VRE), 16 by Williams et al. in the elucidation of binding mode of Van,17,18 and by Whitesides et al. in the studies of multivalency of Van. 19 Learning from the principles developed in the study of low molecular weight organogelators, 7,20 we successfully generated a hydrogelator based on Van by introducing a pyrene group to the C-terminal of the backbone of Van. Our results indicate that the π-π stacking and intermolecular hydrogen bonding in water provide driving forces to form a noncovalent polymer of 1, which is primarily responsible for the gelation. We believe that such an approach, which eliminates the biologically inactive molecules (e.g., cross linked polyacrylamide, etc.) in conventional hydrogels, could lead to a new kind of biomaterial for useful applicationssfor example, controlled releases of therapeutics or surface coatings of medical devices. Figure 1 shows the chemical structure of 1 and the picture of the hydrogel (formed by adding 6.5 mg of 1 into 1.8 mL of water, corresponding to ∼0.36 wt % (2.2 mM) of the gelator and ∼23 000 water molecules/gelator molecule). Figure 2a shows the emission spectra of the hydrogels of 1 at two different concentrations. The broad band of the emission...

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The MICs of 13 antimicrobial agents including seven fluoroquinolones (ciprofloxacin, levofloxacin, sparfloxacin, grepafloxacin, gatifloxacin, moxifloxacin and clinafloxacin) for Streptococcus pneumoniae isolates obtained from all regions of Hong Kong in the year 2000 were determined by the Etest. Overall, 39.4% of 180 isolates were susceptible to penicillin, 11.7% were intermediate and 48.9% were resistant. The overall prevalence of fluoroquinolone non-susceptibility (levofloxacin MIC > or = 4 mg/L) was 13.3% but increased to 27.3% among the penicillin-resistant isolates. For the fluoroquinolone non-susceptible isolates, within-class cross-resistance was common. For the fluoroquinolone non-susceptible isolates, the median MICs of clinafloxacin, gatifloxacin, moxifloxacin, sparfloxacin and grepafloxacin were, respectively, six-, 24-, 32- 84- and 128-fold higher than those for the susceptible isolates. All fluoroquinolone non-susceptible strains were derived from adults. The prevalence of fluoroquinolone resistance was higher in isolates from older patients (17.1% among those > or = 65 years of age versus 9.1% among those 18-64 years of age, P < 0.001) and from adults with chronic obstructive pulmonary disease (24.6% versus 9.3%, P = 0.01). All fluoroquinolone non-susceptible strains were non-susceptible to penicillin (MIC range 2-4 mg/L), cefotaxime (MIC range 1-4 mg/L) and erythromycin (MIC range 4- > or = 256 mg/L). The fluoroquinolone non-susceptible isolates were genetically related to the Spain(23F)-1 clone when analysed by pulse-field gel electrophoresis and multilocus sequence typing. In conclusion, a rapid increase in the prevalence of fluoroquinolone resistance among S. pneumoniae was found in Hong Kong. Typing analysis suggests that this is due to the pan-regional dissemination of a fluoroquinolone-resistant variant (designated Hong Kong(23F)-1) of the globally distributed Spain(23)F-1 clone.

The clinical significance of bacteremia due to vancomycin-heteroresistant staphylococci and a rapid laboratory screening method were examined; 203 strains of staphylococci isolated from patients with clinically significant bacteremia were screened by the disk-agar method with use of vancomycin-salt agar to demonstrate satellitism around an aztreonam disk as well as by conventional population screening. Eighteen isolates (three Staphylococcus aureus and 15 coagulase-negative staphylococci) were shown to be heteroresistant to vancomycin. A case-control clinical study showed that the interval between admission and bacteremia, admission to the intensive care unit, prior use of vancomycin and/or beta-lactams, and isolation of methicillin-resistant staphylococci were significantly more common among patients with bacteremia due to staphylococci with heteroresistance to vancomycin; these patients had an overall mortality of 44.4%. The use of vancomycin and admission to the intensive care unit were independently significant risk factors on multivariate analysis. Vancomycin heteroresistance is inducible by salt and beta-lactams. Indiscriminate sequential use of beta-lactams and glycopeptides may facilitate the emergence of glycopeptide resistance.

A SARS outbreak in the ICU led to changes in the pathogen pattern and the MRSA acquisition rate. The data suggest that MRSA cross-transmission may be increased if gloves and gowns are worn all the time.