This is the first report of a detailed relationship between triazole treatment history and triazole MICs for 154 Aspergillus fumigatus clinical isolates. The duration of itraconazole dosage increased as the itraconazole MIC increased, and a positive correlation was observed ( r = 0.5700, P < 0.0001). The number of itraconazole-naïve isolates dramatically decreased as the itraconazole MIC increased, particularly for MICs exceeding 2 μg/ml (0.5 μg/ml versus 2 μg/ml, P = 0.03). We also examined the relationship between cumulative itraconazole usage and the MICs of other azoles. A positive correlation existed between itraconazole dosage period and posaconazole MIC ( r = 0.5237, P < 0.0001). The number of itraconazole-naïve isolates also decreased as the posaconazole MIC increased, particularly for MICs exceeding 0.5 μg/ml (0.25 μg/ml versus 0.5 μg/ml, P = 0.004). Conversely, the correlation coefficient obtained from the scattergram of itraconazole usage and voriconazole MICs was small ( r = −0.2627, P = 0.001). Susceptibility to three triazole agents did not change as the duration of voriconazole exposure changed. In addition, we carried out detailed analysis, including microsatellite genotyping, for isolates obtained from patients infected with azole-resistant A. fumigatus . We confirmed the presence of acquired resistance to itraconazole and posaconazole due to a G54 substitution in the cyp51A gene for a patient with chronic pulmonary aspergillosis after oral itraconazole therapy. We should consider the possible appearance of azole-resistant A. fumigatus if itraconazole is used for extended periods.
1 January 2012 in Antimicrobial Agents and Chemotherapy
We investigated the triazole, amphotericin B, and micafungin susceptibilities of 196 A. fumigatus clinical isolates in Nagasaki, Japan. The percentages of non-wild-type (non-WT) isolates for which MICs of itraconazole, posaconazole, and voriconazole were above the ECV were 7.1%, 2.6%, and 4.1%, respectively. A G54 mutation in cyp51A was detected in 64.2% (9/14 isolates) and 100% (5/5 isolates) of non-WT isolates for itraconazole and posaconazole, respectively. Amphotericin B MICs of ≥2 μg/ml and micafungin minimum effective concentrations (MECs) of ≥16 μg/ml were recorded for two and one isolates, respectively.
Patients with chronic pulmonary aspergillosis (CPA) have a poor prognosis and CPA occurs in patients with various underlying diseases. Recently, the number of patients with CPA complicated by nontuberculous mycobacteria (NTM) has increased. Additionally, complications of both diseases have several problems like drug interactions. Since the impact of NTM on the outcome of CPA is not well understood, we investigated the risk factors for developing CPA and the clinical characteristics of CPA patients with or without NTM. We retrospectively investigated the medical records of NTM and CPA patients who were admitted to Nagasaki University Hospital between April 2008 and September 2013. Comorbid diseases, causative microorganisms, radiological findings, and outcomes were evaluated. During the study period, 82 and 41 patients were diagnosed as having NTM and CPA, respectively. Nine patients were coinfected with NTM and CPA, and cavitary type NTM and steroid usage were independent risk factors of development of CPA. Mortality rates in the coinfection group were significantly higher than those of the NTM without CPA group (P = .003, log-rank test). The rate of treatment initiation in the co-infection group (33.3%) was significantly lower than in the CPA without NTM group (84.4%) (P = .006). However, there were no significant differences in cumulative survival rate between both groups (P = .760, log-rank test). Cavity formation and steroid usage were the independent risk factors for NTM patients to develop CPA within long observation period, and development of CPA made outcomes poor. It is important to diagnose the development of CPA early and initiate treatment for CPA.
Recent reports indicate that the incidence of nontuberculous mycobacterial-lung disease (NTM-LD) is increasing. This study aimed to investigate the epidemiology and clinical features of NTM-LD patients in Nagasaki prefecture, Japan to identify the negative prognostic factors for NTM-LD in Japan. The medical records of patients newly diagnosed with NTM-LD in eleven hospitals in Nagasaki prefecture between January 2001 and February 2010 were reviewed. Data regarding the annual population of each region and the incidence of all forms of tuberculosis were collected to assess geographic variations in NTM-LD incidence, isolates, and radiological features. A total 975 patients were diagnosed with NTM-LD. The incidence increased over the study period and reached 11.0 and 10.1 per 100,000 population in 2008 and 2009, respectively. M. intracellulare was the most common pathogen in the southern region, and M. avium most common in other regions. The most common radiographic pattern was the nodular-bronchiectatic pattern. Age >60 years, body mass index <18.5 kg/m2, underlying lung disease, and cavitary pattern were the negative prognostic factors at the 1-year follow-up. The incidence of NTM-LD has been increasing in Nagasaki prefecture. The isolates and radiographic features of patients vary markedly by region.
Background: The precise mechanisms of respiratory infection caused by oral anaerobic bacteria remain elusive. Unexpectedly, bacterial microbiota analysis with 16S rRNA revealed “hidden” mixed infections of anaerobic bacteria and commensal oral Streptococcus species in patients with community-acquired pneumonia. The study aimed to elucidate the mechanisms by which Prevotella intermedia exacerbates oral streptococcal pneumonia. Methods: Oral streptococci were oropharyngeally administered with the culture supernatants of P intermedia (PiSup) in mice to assess survival, microbial burden, inflammatory responses, and host response via unbiased bulk RNA sequencing. Additionally, genetically engineered strains of P intermedia were used to identify pathogenic factors. Results: Seven-week-old female C57BL/6J mice treated with the combination of Streptococcus spp and PiSup exhibited significantly worse survival and increased microbial burden in the lungs and spleen when compared with Streptococcus spp and control medium. RNA sequencing of whole lung revealed disruption of neutrophilic bactericidal activity due to NADPH downregulation, accompanied by reduced myeloperoxidase production in mixed infections, leading to dysfunctional neutrophil accumulation in the lungs. Notably, PiSup from strains bearing mutations in the type IX secretion pathway (ΔporT or ΔporK) failed to worsen the mixed infection. Conclusions: P intermedia exacerbates pneumonia caused by commensal oral streptococci by inducing neutrophilic dysfunction in mixed infection. Products of the type IX secretion system should be investigated as novel targets independent of reported virulence factors.