Relationship between upper airway diseases,exhaled nitric oxide,and bronchial hyperresponsiveness to methacholine

Objective: The “united airway disease” concept is based on the bidirectional interaction between asthma and rhinitis. The aim of this study was to determine the relationship between upper airway diseases and bronchial hyperresponsiveness (BHR), as well as their association with the fractional concentration of exhaled nitric oxide (FeNO) and atopy in patients with persistent symptoms suggestive of asthma requiring methacholine challenge testing (MCT) to confirm asthma diagnosis. Methods: A cross-sectional prospective study was carried out in adult patients with persistent asthma-like symptoms and negative bronchodilator testing. FeNO and MCT were performed in all patients. Asthma was confirmed based on the presence of suggestive symptoms and MCT results. Associated upper airway diseases included allergic rhinitis, nonallergic rhinitis, chronic rhinosinusitis with nasal polyps (CRSwNP), and aspirin-exacerbated respiratory disease (AERD). Results: The study included 575 patients; asthma was confirmed in 32.3%, and FeNO values ≥ 50 ppb were found in 27% of the patients. Elevated FeNO was significantly associated to AERD. The prevalence of atopy in asthma patients was 86.6%. Atopy was present in 90.4% of patients with asthma and FeNO levels ≥ 50 ppb. A significant association was found between AERD, asthma, and FeNO ≥ 50 ppb. Conclusions: Patients with symptoms suggestive of asthma but negative bronchodilator testing are commonly seen in usual practice. In this population, the association of high FeNO levels and BHR to atopy, as well as to AERD, suggests the presence eosinophilic inflammation in both the upper and lower airways and supports the “one airway” hypothesis.     

Bacteriophage effectively kills multidrug resistant Staphylococcus aureus clinical isolates from chronic rhinosinusitis patients

Background

Bacteriophage (phage) therapy has been proposed as an alternative to antibiotics. Phages have been shown to kill antibiotic resistant Staphylococcus aureus strains; however, it is unknown whether stress‐induced antibiotic tolerance affects S. aureus susceptibility to phages. Our objective was to determine the effectiveness of 2 phages currently in clinical development, against antibiotic‐resistant and induced antibiotic‐tolerant clinical S. aureus isolates.

Methods

Antibiotic tolerant S. aureus strains were induced by incubation with increasing concentrations of gentamicin, mupirocin, and ciprofloxacin over time and their susceptibility to 2 clinically relevant phages (Sa83 and Sa87) was assessed. In addition, phage susceptibility was tested in relation to the antibiotic sensitivity of 65 clinical S. aureus isolates, harvested from the sinonasal cavities of chronic rhinosinusitis (CRS) patients. Phage sensitivity was assessed using a plaque spot assay and by measuring optical density values to observe planktonic S. aureus growth in the presence of the phage. Alamar Blue assays were used to assess biofilm viability after phage treatment.

Results

Frequency of antibiotic resistance amongst clinical S. aureus isolates was 90.7% (59/65) with 13 of 65 (20.0%) identified as multidrug‐resistant. Tolerance to gentamicin, mupirocin, and ciprofloxacin was rapidly induced by incubation with increasing concentrations of respective antibiotics. There was no significant difference in phage sensitivity between antibiotic‐sensitive and resistant/tolerant S. aureus clinical isolates in planktonic and biofilm form.

Conclusion

Clinical S. aureus isolates from CRS patients have a high (20%) incidence of multidrug resistance. Antibiotic resistance or tolerance did not affect phage susceptibility of those isolates.

     

社区获得性耐甲氧西林金黄色葡萄球菌

社区获得性耐甲氧西林金黄色葡萄球菌是社区感染中重要的致病菌之一,以往由其所致感染多发生在医院环境,如今其引起的社区感染的比例不断上升.自1961年发现第1株耐甲氧西林金黄色葡萄球菌以来,耐甲氧西林金黄色葡萄球菌在世界各地流行并引起暴发流行,耐药程度不断加重.尤其1996年万古霉素不敏感金黄色葡萄球菌及2002年耐万古霉素金黄色葡萄球菌的出现,显示其对人类的威胁愈趋严重,已成为当今感染医学一个难题.本文介绍社区获得性耐甲氧西林金黄色葡萄球菌的流行情况及防治措施.     

Investigation of a cluster of Staphylococcus aureus invasive infection in the Top End of the Northern Territory

Introduction: Staphylococcus aureus invasive infection remains a serious condition associated with considerable morbidity and mortality. Following notification of five cases at Royal Darwin Hospital (RDH), we searched for related cases, determined their epidemiological characteristics and attempted to identify the source of this apparent cluster. Methods: We reviewed RDH microbiology records between June 1996 and April 1997 for S. aureus isolates with similar antibiograms to notified cases. We used antibiotic resistance patterns, bacteriophage typing and two molecular typing techniques to subtype implicated isolates. Hospital records were reviewed for admission details and associated costs were estimated. Results: Fifty-four cluster-related isolates occurred in 47 separate presentations. The peak incidence was in the wet season. The most important risk factor for staphylococcal invasive infection was the presence of skin sores/scabies in 17/54 cases (31%), followed by intravascular line use in 14/54 (26%), open trauma in 11/54 (20%), underlying end stage renal failure and alcoholism each in ten of 54 (18%). The mean admission length was 30 days and antibiotics were given for an average of 23 days. Death due to S. aureus infection occurred in eight of 47 (17%) presentations. S. aureus pneumonia was community acquired in 12/13 patients (92%) and six of 13 (46%) died. Ten of 13 (80%) pneumonia patients had at least one other focus of S. aureus infection. The cost of antibiotics and hospital bed per presentation was approximately $16,000. Presentations with skin sores/scabies cost considerably more ($31,000). No common epidemiologic features were found for community or hospital acquired cases. Conclusion: Considerable mortality and cost was attributable to cases of S. aureus invasive infection during this cluster; particularly those with community acquired pneumonia or skin sores/scabies. Staphylococcal antibiotic cover should be considered early for unwell patients presenting to hospital with pneumonia and other signs of potential S. aureus infection. It is appropriate to target public health efforts to prevent skin sores and to provide adequate treatment when they occur.