The activity of 7 antifungal agents against 3,557 invasive yeasts and molds collected in 29 countries worldwide in 2014 and 2015 was evaluated. Epidemiological cutoff values (ECVs) published in the Clinical and Laboratory Standards Institute (CLSI) M59 document were applied for species with no clinical breakpoints. Echinocandin susceptibility rates were 95.9% to 100.0% for the 5 most common species, except for the rates for to anidulafungin (88.7% susceptible, 100.0% wild type). Rates of fluconazole resistance ranged from 8.0% for to 0.4% for Seven species displayed 100.0% wild-type amphotericin B MIC results, and and exhibited wild-type echinocandin MIC results. The highest fluconazole, voriconazole, and posaconazole MIC values for var. were 8 μg/ml, 0.12 μg/ml, and 0.25 μg/ml, respectively. isolates were 100.0% wild type for caspofungin and amphotericin B, but 3 (0.8%) of these isolates were non-wild type to itraconazole (2 isolates) or voriconazole (1 isolate). Mutations in hot spot (HS) regions were detected among 13/20 isolates displaying echinocandin MICs greater than the ECV (16 of these 20 isolates were ). Most isolates carrying mutations in HS regions were resistant to 2 or more echinocandins. Five fluconazole-nonsusceptible isolates were submitted to whole-genome sequencing analysis. Gain-of-function, heterozygous, and homozygous mutations were observed in 1 isolate each. One isolate displayed MDR1 promoter allele alterations associated with azole resistance. Elevated levels of expression of MDR1 or CDR2 were observed in 3 isolates and 1 isolate, respectively. Echinocandin and azole resistance is still uncommon among contemporary fungal isolates; however, mechanisms of resistance to antifungals were observed among spp., showing that resistance can emerge and monitoring is warranted.

Plazomicin and comparator agents were tested by using the CLSI reference broth microdilution method against 4,825 clinical isolates collected during 2014 and 2015 in 70 U.S. hospitals as part of the ALERT (Antimicrobial Longitudinal Evaluation and Resistance Trends) program. Plazomicin (MIC/MIC, 0.5/2 μg/ml) inhibited 99.2% of 4,362 at ≤4 μg/ml. Amikacin, gentamicin, and tobramycin inhibited 98.9%, 90.3%, and 90.3% of these isolates, respectively, by applying CLSI breakpoints. The activities of plazomicin were similar among species, with MIC values ranging from 0.25 to 1 μg/ml, with the exception of and indole-positive that displayed MIC values of 2 μg/ml. For 97 carbapenem-resistant (CRE), which included 87 isolates carrying, plazomicin inhibited all but 1 isolate at ≤2 μg/ml (99.0% and 98.9%, respectively). Amikacin and gentamicin inhibited 64.9% and 56.7% of the CRE isolates at the respective CLSI breakpoints. Plazomicin inhibited 96.5 and 95.5% of the gentamicin-resistant isolates, 96.9 and 96.5% of the tobramycin-resistant isolates, and 64.3 and 90.0% of the amikacin-resistant isolates according to CLSI and EUCAST breakpoints, respectively. The activities of plazomicin against (MIC/MIC, 4/16 μg/ml) and species (MIC/MIC, 2/16 μg/ml) isolates were similar. Plazomicin was active against coagulase-negative staphylococci (MIC/MIC, 0.12/0.5 μg/ml) and (MIC/MIC, 0.5/0.5 μg/ml) but had limited activity against spp. (MIC/MIC, 16/64 μg/ml) and (MIC/MIC, 32/64 μg/ml). Plazomicin activity against the tested, including CRE and isolates carrying from U.S. hospitals, supports the development plan for plazomicin to treat serious infections caused by resistant in patients with limited treatment options.

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Staphylococcus aureus isolates from bovine milk were assessed for capsule or slime production. When pure S. aureus cultures in milk were inoculated directly into serum-soft agar constituted with a modified staphylococcus 110 medium, 100% of the isolates grew with diffuse colony morphology. Diffuse colony morphology was rapidly lost on subculture and was more rapidly lost in brain heart infusion-serum-soft agar. No evidence was seen for encapsulation in India ink preparations or by the clumping factor test. It was concluded that freshly isolated S. aureus strains produce slime, not true capsules. During examination of the 84 milk samples that grew staphylococci in addition to S. aureus (27.4%), a significant number of coagulase-negative staphylococcal species were encountered and identified by conventional tests as S. simulans (41.7%), S. xylosus (11.9%), S. epidermidis (3.6%), S. saprophyticus (3.6%), S. hyicus (2.9%), S. cohnii (1.2%), S. haemolyticus (1.2%), and S. warneri (1.2%). Five isolates (6.0%) were not identified. Attempts were also made to identify the isolates by the API Staph-Ident system, which gave an overall accuracy of 45.2%. The susceptibilities of the isolates to a variety of antibiotics were determined, and they appeared to be less resistant than human clinical isolates.

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