The emergence of multidrug-resistant and extensively drug-resistant (XDR) tuberculosis (TB) is a serious global threat. Aminoglycoside antibiotics are used as a last resort to treat XDR-TB. Resistance to the aminoglycoside kanamycin is a hallmark of XDR-TB. Here, we reveal the function and structure of the mycobacterial protein Eis responsible for resistance to kanamycin in a significant fraction of kanamycin-resistant Mycobacterium tuberculosis clinical isolates. We demonstrate that Eis has an unprecedented ability to acetylate multiple amines of many aminoglycosides. Structural and mutagenesis studies of Eis indicate that its acetylation mechanism is enabled by a complex tripartite fold that includes two general control non-derepressible 5 (GCN5)-related N -acetyltransferase regions. An intricate negatively charged substrate-binding pocket of Eis is a potential target of new antitubercular drugs expected to overcome aminoglycoside resistance.

We have previously described a cyclic tetrapeptide, 1, that displays μ opioid receptor (MOPr) agonist and δ opioid receptor (DOPr) antagonist activity, a profile associated with a reduced incidence of opioid tolerance and dependence. Like many peptides, 1 has poor bioavailability. We describe here an analogue of 1 with an added C-terminal β-glucosylserine residue, Ser(β-Glc)NH2, a modification that has previously been shown to improve bioavailability of opioid peptides. The resulting peptide, 4, exhibits full antinociceptive efficacy in the mouse warm water tail withdrawal assay after intraperitoneal administration with potency similar to that of morphine. Further, 4 does not give rise to acute tolerance and thus represents a promising lead for the development of opioid analgesics with reduced side effects.

BackgroundBacterial resistance to antibiotics is thought to develop only in the presence of antibiotic pressure. Here we show evidence to suggest that fluoroquinolone resistance in Escherichia coli has developed in the absence of fluoroquinolone use.MethodsOver 4 years, outreach clinic attendees in one moderately remote and five very remote villages in rural Guyana were surveyed for the presence of rectal carriage of ciprofloxacin-resistant Gram-negative bacilli (GNB). Drinking water was tested for the presence of resistant GNB by culture, and the presence of antibacterial agents and chloroquine by HPLC. The development of ciprofloxacin resistance in E. coli was examined after serial exposure to chloroquine. Patient and laboratory isolates of E. coli resistant to ciprofloxacin were assessed by PCR-sequencing for quinolone-resistance-determining-region (QRDR) mutations.ResultsIn the very remote villages, 4.8% of patients carried ciprofloxacin-resistant E. coli with QRDR mutations despite no local availability of quinolones. However, there had been extensive local use of chloroquine, with higher prevalence of resistance seen in the villages shortly after a Plasmodium vivax epidemic (p<0.01). Antibacterial agents were not found in the drinking water, but chloroquine was demonstrated to be present. Chloroquine was found to inhibit the growth of E. coli in vitro. Replica plating demonstrated that 2-step QRDR mutations could be induced in E. coli in response to chloroquine.ConclusionsIn these remote communities, the heavy use of chloroquine to treat malaria likely selected for ciprofloxacin resistance in E. coli. This may be an important public health problem in malarious areas.

OBJECTIVE To measure transmission frequencies and risk factors for household acquisition of community-associated and healthcare-associated (HA-) methicillin-resistant Staphylococcus aureus (MRSA). DESIGN Prospective cohort study from October 4, 2008, through December 3, 2012. SETTING Seven acute care hospitals in or near Toronto, Canada. PARTICIPANTS Total of 99 MRSA-colonized or MRSA-infected case patients and 183 household contacts. METHODS Baseline interviews were conducted, and surveillance cultures were collected monthly for 3 months from household members, pets, and 8 prespecified high-use environmental locations. Isolates underwent pulsed-field gel electrophoresis and staphylococcal cassette chromosome mec typing. RESULTS Overall, of 183 household contacts 89 (49%) were MRSA colonized, with 56 (31%) detected at baseline. MRSA transmission from index case to contacts negative at baseline occurred in 27 (40%) of 68 followed-up households. Strains were identical within households. The transmission risk for HA-MRSA was 39% compared with 40% (P=.95) for community-associated MRSA. HA-MRSA index cases were more likely to be older and not practice infection control measures (P=.002-.03). Household acquisition risk factors included requiring assistance and sharing bath towels (P=.001-.03). Environmental contamination was identified in 78 (79%) of 99 households and was more common in HA-MRSA households. CONCLUSION Household transmission of community-associated and HA-MRSA strains was common and the difference in transmission risk was not statistically significant. Infect Control Hosp Epidemiol 2016;1-7.

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bWe analyzed the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) of smudge plate growth for bacterial identification from 400 blood cultures. Ninety-seven percent of Gram-negative bacilli and 85% of Gram-positive organisms were correctly identified within 4 h; only eight isolates (2.0%) were misidentified. This method provided rapid and accurate microbial identification from positive blood cultures. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is used in clinical microbiology laboratories for rapid identification of microbial isolates grown in culture (1, 2). Implementation of MALDI-TOF MS in the microbiology laboratory in conjunction with antibiotic stewardship has been associated with earlier initiation of effective antimicrobial therapy and lower 30-day mortality in patients with bloodstream infections (3). This technology has also been applied to reduce turnaround times for identification of blood culture isolates directly from positive blood culture broths (4-16). Various techniques have been assessed, generally involving lysis/centrifugation of blood culture pellets in preparation for analysis by MALDI-TOF MS. The current study evaluated a method using "smudge" plates for subsequent analysis with MALDI-TOF MS to simplify sample processing and to improve the ability to rapidly identify bacteria from positive blood cultures.Blood cultures were collected in Bactec Plus aerobic and anaerobic bottles incubated in the Bactec 9240 system (Becton Dickinson, Franklin Lakes, NJ). We prospectively examined 400 blood cultures that were flagged as positive for bacterial growth between 8:00 a.m. and 3:00 p.m. on weekdays from 1 April to 30 September 2014. A 1-to 2-ml aspirate from the blood culture bottle was used to prepare a Gram stain and was subcultured to blood, chocolate, and MacConkey agar plates. The blood and MacConkey plates were incubated at 35°C in ambient air; chocolate agar plates were incubated at 35°C in 5% CO 2 . Brucella agar plates incubated anaerobically were added for subculture from positive anaerobic blood culture bottles. Aerobic and facultative organisms were identified using standard phenotypic methods, including coagulase, oxidase, latex agglutination, streptococcal serotyping, the Vitek 2 system (bioMérieux, Durham, NC), API strips (bioMérieux), and other biochemical tests as appropriate. Anaerobes were identified using the Remel RapID Ana II (Oxoid, Hampshire, United Kingdom).A smudge plate was prepared when a single morphology was evident on the Gram stain; specimens with more than one bacterial morphology, yeasts, or filamentous fungi were excluded from this study. If two blood culture bottles from the same set were positive, only the aerobic bottle was used for smudge plate preparation, and multiple positive blood cultures obtained within 24 h from the same patient were included in this study only once. For smudge plate preparation, 3 ml of blood culture broth was aspirated from positive blood cultu...

This particular population of hospitalized IBD patients was not shown to have a higher prevalence or incidence of ARO colonization or infection compared with non-IBD inpatients.

identification of Candida species from positive blood cultures by use of the FilmArray blood culture identification panel.