Dental units as infection sources of Pseudomonas aeruginosa

First water safety plan approach applied to a Dental Clinic complex: identification of new risk factors associated with Legionella and P. aeruginosa contamination, using a novel sampling, maintenance and management program

Dental unit waterlines (DUWLs) represent a complex environment able to promote microbial contamination, due to functional, mechanical and practical risk factors. According to a water safety plan approach, the main goal is to preserve the health of dentists, dental staff and patients. The aim of this study is to develop a DUWLs water safety plan that is able to support correct and effective maintenance and disinfection procedures. Three different water systems serve 60 dental chairs: (i) water that comes directly from municipal water (Type A), (ii) water supplied by municipal water and water bottles (Type B) and (iii) water supplied only via water bottles (Type C). For each type, Legionella and Pseudomonas aeruginosa contamination was studied, by applying a new sampling scheme, based on separate sampling from water bottles, cup filler and handpieces. Type B DUWL is the only type of DUWL contaminated by L. pneumophila (ST 59) and L. anisa (mean contamination: 608.33 ± 253.33 cfu/L) detected in cup filler and handpieces, as well as the high presence of P. aeruginosa (44.42 ± 13.25 cfu/100 mL). Two subsequent shock treatments and resampling procedures were performed by increasing disinfectant dosage and contact time and removing some DUWL components linked to biofilm growth in DUWLs. A significant reduction of contamination was obtained for both microorganisms (Legionella spp.: -100%, p < 0.001 and P. aeruginosa: -99.86%, p = 0.006). The sampling strategy proposed allows us to identify the source of contamination and better focus on the maintenance and disinfection procedures. DUWLs represent an environment that requires a multidisciplinary approach, combining the knowledge of all DUWL components to correct procedures that are able to preserve the health of personnel and patients, as well as guaranteeing DUWLs' safe functionality.

Development of a customized mask retainer for improving the fit performance of surgical masks

This study introduces a customized mask retainer to improve the fit performance of surgical masks using various advanced digital techniques. The participant's 3D face scans with and without a surgical mask were taken by using a smartphone. The mask retainer was designed using the 3D face scan data based on the facial anthropometric landmarks. The fitting was inspected and adjusted using the masked face scan data. The retainer was fabricated using a 3D printer. The effectiveness of the retainer on the augmentation of the fit of the surgical mask was tested according to the Chinese Standard (GB 19083-2010). A questionnaire was used to assess the effect of wearing surgical masks with and without retainers and N95 respirators on subjective perception of discomfort. The effectiveness test of the retainer on the augmentation of the fit performance showed a better than 25-fold increase in the overall fit factor, meeting the fit requirement for KN95 respirators in China. The subjective perception of discomfort of wearing N95 was significantly greater than surgical mask with and without retainers. The fit factor results indicated that by using the retainer, the overall fit factors and that of each exercise significantly increased compared to that of the group with the surgical mask alone. And compared with N95, the surgical mask with the retainer significant improved comfort. The surgical mask with the retainer can provide an alternative of personal protective equipment for healthcare workers.

Environmental risks of Pseudomonas aeruginosa-What to advise patients and parents

Pseudomonas aeruginosa (PsA) is commonly found in soil and water so is impossible to avoid completely. Parents/carers of children with cystic fibrosis (CF) are concerned about them acquiring PsA from the environment, and different families view risk differently. Our ethos is to enable children with CF to take part as much as possible in educational and fun home activities, in order to maintain their quality of life (and their family's), and not have them feel different from other children. This review presents advice for families as to what they must definitely avoid, what they must take precautions with but can allow, and what they must not avoid. It is mostly evidence-based, but where evidence is lacking it a consensus view from the Paediatric CF Unit at the Royal Brompton Hospital.

Treatments for preventing recurrence of infection with Pseudomonas aeruginosa in people with cystic fibrosis

BACKGROUND

Chronic infection with Pseudomonas aeruginosa (PA) in cystic fibrosis (CF) is a source of much morbidity and mortality. Eradication of early PA infection is possible, but can recur in many individuals. We sought to examine strategies to delay the time to PA recurrence in people with CF.

OBJECTIVES

To establish whether secondary prevention strategies, using antibiotics or other therapies, increase the chances of people with CF remaining free from PA infection following successful eradication therapy.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched ongoing trials registries and the reference lists of relevant articles and reviews. Date of last search: 21 August 2019.

SELECTION CRITERIA

Randomised controlled trials (and quasi-randomised trials where the risk of bias was low) comparing any treatment modality aimed at preventing recurrence of PA infection with placebo, standard therapy or any other treatment modality in people with CF who have undergone successful eradication of PA.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias. Quality of the evidence was assessed using GRADE. Conflicts were resolved by discussion and the opinion of a third review author was sought where necessary. Only a subset of participants in the included trial were eligible, therefore individual participant data were requested and obtained from the trial investigators.

MAIN RESULTS

We included one trial (n = 306) in the review; however, only 253 participants had undergone successful eradication of PA, so fulfilling the inclusion criteria for our review. Information presented relates only to the included subset of participants. The trial recruited children aged one to 12 years (mean (standard deviation (SD)) age of 5.8 (3.5) years), 129 participants (51.0%) were female and the median follow-up was 494 days. We compared cycled therapy with tobramycin inhalation solution (TIS), in which participants underwent 28 days of TIS every three months, with culture-based therapy, in which participants were only prescribed medication when a quarterly sputum sample was positive for PA. Reasons for downgrading the quality of the evidence included applicability (only included children), incomplete outcome data and a small number of participants. The time to next isolation of PA was probably shorter with cycled TIS therapy than with culture-based therapy, hazard ratio (HR) 2.04 days (95% confidence interval (CI) 1.28 to 3.26) (moderate-quality evidence). This is in contrast to the main publication of the only included trial, which examined rate of PA positivity rather than time to PA infection and included participants not eligible for inclusion in this review. At the end of the trial, there was no difference between the cycled and culture-based groups in the change from baseline in forced expiratory volume in one second (FEV₁) L, mean difference (MD) 0.0 L (95% CI -0.09 to 0.09) or in FEV₁ % predicted, MD 0.70% (95% CI -4.33 to 5.73) (both very low-quality evidence). There was no difference in the change from baseline for FVC between the groups. There was also no difference in the frequency of pulmonary exacerbations between groups, MD -0.18 (95% CI -0.51 to 0.14) (moderate-quality evidence). Similarly, there was no difference between groups in the risk of participants developing novel resistant bacteria, RR 1.00 (95% CI 0.67 to 1.5) (moderate-quality evidence). There were more severe adverse events in the cycled group, but the type of treatment probably makes little or no difference to the results, RR 0.65 (95% CI 0.39 to 1.11) (moderate-quality evidence). There was no difference between groups in the change in weight or height from baseline or in rates of adherence to tobramycin or all trial medicines. The included trial did not assess changes in quality of life, the time to chronic infection with PA or the cost-effectiveness of treatment.

AUTHORS' CONCLUSIONS

Cycled TIS therapy may be beneficial in prolonging the time to recurrence of PA after successful eradication, but further trials are required, specifically addressing this question and in both adults and children.

Pseudomonas aeruginosa Acquisition in Cystic Fibrosis Patients in Context of Otorhinolaryngological Surgery or Dentist Attendance: Case Series and Discussion of Preventive Concepts

Introduction. P. aeruginosa is the primary cause for pulmonary destruction and premature death in cystic fibrosis (CF). Therefore, prevention of airway colonization with the pathogen, ubiquitously present in water, is essential. Infection of CF patients with P. aeruginosa after dentist treatment was proven and dental unit waterlines were identified as source, suggesting prophylactic measures. For their almost regular sinonasal involvement, CF patients often require otorhinolaryngological (ORL) attendance. Despite some fields around ORL-procedures with comparable risk for acquisition of P. aeruginosa, such CF cases have not yet been reported. We present four CF patients, who primarily acquired P. aeruginosa around ORL surgery, and one around dentist treatment. Additionally, we discuss risks and preventive strategies for CF patients undergoing ORL-treatment. Perils include contact to pathogen-carriers in waiting rooms, instrumentation, suction, drilling, and flushing fluid, when droplets containing pathogens can be nebulized. Postsurgery mucosal damage and debridement impair sinonasal mucociliary clearance, facilitating pathogen proliferation and infestation. Therefore, sinonasal surgery and dentist treatment of CF patients without chronic P. aeruginosa colonization must be linked to repeated microbiological assessment. Further studies must elaborate whether all CF patients undergoing ORL-surgery require antipseudomonal prophylaxis, including nasal lavages containing antibiotics. Altogether, this underestimated risk requires structured prevention protocols.

Eradication of early Pseudomonas infection in cystic fibrosis

Chronic infection with the environmental bacterium Pseudomonas aeruginosa is associated with greater morbidity and mortality for people with cystic fibrosis. Strict infection control measures including segregation appear to reduce but not eliminate the risk of initial acquisition of the organism. There is now good evidence from randomized controlled trials that early eradication regimens consisting of anti-pseudomonal antibiotics are effective in clearing P. aeruginosa and delaying the development of chronic infection in the majority of subjects. These regimens are safe and cost-effective. Ensuring that such regimens are widely adopted is therefore of considerable importance to improving outcomes for people with cystic fibrosis. The most effective antibiotic regimen, and the effects of new nebulizer technologies and methods to improve concordance remain to be determined.