PHASTER: a better, faster version of the PHAST phage search tool

PHASTER: a better, faster version of the PHAST phage search tool. MIC50s of 0.25 (ceftaroline with 100?g/ml ceftazidime) and 0.5?g/ml (imipenem with 100?g/ml ceftazidime) against medical MABC isolates. Related synergy was observed in time-kill studies against the ATCC 19977 strain using clinically attainable concentrations of either imipenem (4?g/ml) or ceftaroline (2?g/ml), while the addition of ceftazidime at concentrations of 50?g/ml showed a persistent bactericidal effect over 5?days. Treatment of THP-1 human being macrophages infected with three different medical isolates supported the findings, as the combination of 100?g/ml ceftazidime and 0.125?g/ml ceftaroline or 100?g/ml ceftazidime and 0.25?g/ml imipenem dramatically reduced the CFU counts to near baseline levels of illness. This studys finding that there is synergy between particular -lactam mixtures against illness provides optimism toward identifying an optimum dual -lactam treatment routine. complex (MABC) strains (1,C3). These FF-10101 rapidly growing nontuberculous mycobacteria (NTM) cause chronic infections in immunocompromised individuals, including individuals with malignancy and transplant recipients, as well as with individuals with chronic lung disease, such as cystic fibrosis (4, 5). In most cases the infections are resistant to most antituberculosis agents and to additional major antibiotic classes (2). The recent acknowledgement of macrolide resistance offers further narrowed treatment options (2). Combination drug regimens, which may include a -lactam, aminoglycoside, macrolide, linezolid, or tigecycline, are routinely prescribed, but fewer than one-half of individuals with pulmonary disease accomplish sputum culture conversion (6, 7). Regrettably, treatment failures and recurrences are frequently reported (7,C9). With the rapidly growing quantity of vulnerable populations, there is an urgent need for novel treatment methods that are more likely to achieve medical remission. Genomic analyses, although limited, have dramatically improved our knowledge concerning the phylogenetic relatedness among the MABC strains: subsp. subsp. FF-10101 subsp. (10,C12). Comparative genomics offers exposed recombination among the subspecies and with additional NTM species, therefore creating admixed strains that are associated with chronic colonization and lung infections (13). Mining of putative resistance genes recognized the acquisition of (14,C16) to be associated with the emergence of macrolide resistance; the mutation was found to be associated with amikacin resistance, and the initial characterization of the complex -lactamase (BlaMab) and transpeptidases were found to be related to -lactam resistance (17,C19). With the current focus on drug finding for multidrug-resistant Gram-negative pathogens and the need to overcome the emergence of carbapenem resistance, there are now active pharmaceutical programs developing -lactamase inhibitors and medical research efforts investigating dual -lactam therapy (20, 21). Currently, the MABC treatment recommendations include the use of the -lactam cefoxitin (a cephalosporin) or imipenem (a carbapenem) (22,C24). Although they are more stable than additional -lactams in the presence of the principal -lactamase, BlaMab, their medical efficacy remains uncertain. Recent studies show that, unlike additional promoted -lactamase inhibitors, the new non–lactam agent avibactam efficiently inhibits BlaMab and significantly enhances the activity of additional -lactams against transpeptidases, these results suggest that dual -lactam regimens with or without avibactam may have greater activity than a solitary agent (7, 17, 28). In this study, we collected 29 clinical complex respiratory isolates from different organizations. All isolates were characterized by XCL1 whole-genome sequencing, and each was tested against ceftaroline and imipenem, alone and in combination with ceftazidime-avibactam, a newly promoted cephalosporinC-lactamase inhibitor combination. Surprisingly, despite the poor activity of ceftazidime with or without avibactam, the dual -lactam mixtures of ceftazidime with either ceftaroline or imipenem showed promising synergistic activities against the MABC strains. This finding may catalyze a new strategy of combining -lactams to more effectively treat this highly debilitating chronic illness. RESULTS Bacterial strains and genomic characterization. A total of 30?complex FF-10101 strains, including the reference strain ATCC 19977, were characterized by whole-genome sequencing and determined to the subspecies level as subsp. subsp. subsp. strains. Open in a separate window FIG?1 Phylogenetic analysis and susceptibility testing of complex isolates. The MICs of 2, 4, and 8?g/ml were defined as susceptible, intermediate, and resistant to clarithromycin. Acquired clarithromycin resistance was identified at day time 3, while inducible clarithromycin resistance was identified at day time 14. The analysis of genes associated with macrolide resistance.