Attitudes to cross infection, nebuliser hygiene and antimicrobial resistance in people with cystic fibrosis: Results of an international survey.

BACKGROUND: Respiratory infection is a major cause of disease severity in people with cystic fibrosis (PwCF). This project aimed to establish the CF community's opinion regarding cross infection (CI), nebuliser hygiene, antimicrobial resistance, personal impact of microbiological findings and the role of the microbiology laboratory. METHODS: A questionnaire was completed anonymously (n = 280; PwCF (n = 128), parents (n = 123); friends/family/carers/charity personnel (n = 29)) from 13 countries. Readability scores (Flesch Reading Ease (FRE), Flesch Kincaid Grade Level (FKGL)) were determined for CI/IP&C information from six national CF charities and 21 scientific abstracts. RESULTS: Respondents (72.5%) indicated knowledge of laboratory aspects of CF microbiology was important, however implications of microbiological findings on personal health/well-being were of higher importance (p < 0.0001). Cross infection/infection prevention & control (CI/IP&C) was of highest importance (95.6% respondents) with 27.3% indicating they were not given adequate information, particularly in older respondents (50 y+) (p = 0.006) versus young adults (16-29 y) and respondents from the Middle East versus N. America (p = 0.022) and Europe (p = 0.045). Responses highlighted how CI/IP&C health literacy could be enhanced. Respondents (77.3%), particularly females (p < 0.0001), indicated they would increase the frequency of nebuliser disinfection following guidance on infection risks/best practice, therefore an educational video was prepared. CI/IP&C readability scores (mean ± sd) from CF charities (FRE 52.5 ± 10.8; FKGL 9.7 ± 2.3) were more readable (p < 0.0001) than scientific abstracts (FRE 13.3 ± 11.1; FKGL 16.9 ± 2.3), however not meeting the targets (FRE≥60 and FKGL≤8). CONCLUSION: There is a requirement for further CI/IP&C evidence-based guidance, policies/guidelines, education awareness, best practice in the home environment and multi-modal communication, enabling the CF community to make informed choices on lifestyle behaviours.

Time-to-first-isolation of methicillin-resistant Staphylococcus aureus (MRSA) in cystic fibrosis (CF): An underutilised metric in infection control?

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a significant pathogen in people with cystic fibrosis (PwCF). There is a paucity of reports on MRSA infection dynamics within CF. It was the aim to examine the utility of Time-To-FirstIsolation (TTFI) metric and to correlate this with patient gender and CF transmembrane conductance regulator (CFTR) mutation type. METHODS: The microbiology of respiratory specimens from 100 adult (≥18 years) PwCF was examined (50 females; 50 males; mean age 24.6 years ±6.25 (SD)) from birth to present, equating to 2455 patient years. TTFI was determined in relation to (i) presence/absence of MRSA, (ii) CFTR mutation type and (iii) PwCF gender. RESULTS: MRSA was noted in 23% patients (10 female/13 males); (i) F508del/F508del homozygous (43.5%) and (ii) F508del/other heterozygous (56.5%). No non-F508del CFTR mutations types were noted. The median and mean TTFI was 137 months and 127.4 months respectively, shortest time was 23 months, longest time 211 months. There was no statistical significance in TTFI in relation to CFTR mutation group (p = 0.39) or gender (p = 0.71). CONCLUSIONS: TTFI is useful and applicable to the chronic infection model, where patients with a specific underlying disease are predisposed to acquire infections and where these infections are likely to become chronic. Intelligence offered by TTFI provides a window of opportunity to target IPC interventions, to help prevent MRSA acquisition. CF multidisciplinary teams, microbiologists and infection prevention specialists should utilise such TTFI data from their respective centres to help inform and plan intervention strategies to help prevent MRSA acquisition.

Infection Dynamics of Aspergillus fumigatus in Adults with Cystic Fibrosis (CF).

OBJECTIVE: Aspergillus fumigatus (A. fumigatus) has emerged as a significant pathogen in patients with cystic fibrosis (CF) and currently is within the top five isolated organisms reported in several international CF patient registries. A. fumigatus has been attributed to disease progression, although its role remains controversial. There is a paucity of reports on its infection dynamics, it was the aim of this study to examine time to first laboratory reports of A. fumigatus acquisition and to correlate this with patient gender and cystic fibrosis transmembrane conductance regulator (CFTR) mutation type. METHODS: One hundred adult (≥ 18 years) CF patients were examined (50 females, 50 males; mean age 24.6 years ± 6.25 (SD), median age 24 years; maximum age 76 years). CFTR mutation groups consisted (i) F508del/F508del homozygous (n = 45), (ii) F508del/other heterozygous (n = 45) and (iii) others (n = 10). CFTR mutation type, patient gender, presence/absence of A. fumigatus and time (months) to first isolation of A. fumigatus were examined. RESULTS: Microbiological data was examined from 100 patients from birth to present (31/12/2021), equating to 2455 patient years. A. fumigatus was isolated from 66/100 (66%) adult CF patients; (i) F508del/F508del homozygous (82%; 37/45), (ii) F508del/other heterozygous (56%; 25/45) and (iii) others (40%; 4/10). Within the F508del/other heterozygous group, 14 mutations were noted on the second allele, with R560T and R117H collectively accounting for 36% of the second mutations. Four unique allele/allele mutations were noted in the Other Mutations category. There was a trend to a higher A. fumigatus acquisition in F508del/F508del homozygous patients than with F508del/other patients (p = 0.0529). Of the 66 patients who were positive for A. fumigatus, 35(53%) were male and 31(47%) were female. The median and mean time to first isolation of A. fumigatus in all A. fumigatus-positive patients was 119.5 months and 128 months, respectively, shortest time was 12 months, longest time 288 months. There was a statistical significance in time-to-first isolation in relation to CFTR mutation group (p = 0.0272), whereby F508del homozygous individuals had their first isolation of A. fumigatus at 116.8 ± 7.9 months (mean ± standard error of the mean (SEM)) and F508del heterozygous patients had their first isolate of A. fumigatus at 150.4 months ± 13.7 months (mean ± SEM), approximately 2.75 years after their F508del homozygous peers. There was no significant difference (p = 0.12) in time to first acquisiton between males and females, whereby males had their first A. fumigatus isolate at 118 ± 9.4 months, whereas females had their first A. fumigatus isolate at 140 ± 10.8 months. The highest rate of first A. fumigatus isolation was from 4 years until 16 years and by the age of 16 years, approximately 85% of A. fumigatus-positive patients had recorded their first A. fumigatus isolate. CONCLUSION: To minimise the risk of first acquisition of A. fumigatus, it is important that infection prevention educational messaging is delivered in the paediatric clinic, to enhance health literacy around A. fumigatus acquisition.

Cystic fibrosis: Infection prevention & control recommendations for universities, colleges and institutes of further and higher education - A practical guide.

BACKGROUND: The avoidance of cross-infection remains of critical importance to prevent the transmission of cystic fibrosis (CF)-related microbial pathogens to persons/people with cystic fibrosis (PwCF). To date, there has been a paucity of infection prevention and control (IPC) guidance relating to infection risk at higher educational institutions. With improvements in treatments, more PwCF are now attending universities/colleges and educational institutions now seek CF-specific guidance on IPC from clinical CF teams/centres. METHODS: Real world infection-related questions from university students, educators, university support staff and the CF multidisciplinary team were received and collated from various stakeholders, including individual consultations and focus group sessions with two local universities. Subsequently, evidence-based recommendations were compiled from existing peer-reviewed literature and from cystic fibrosis organisations. Glossaries were constructed relating to clinical, microbiological and educational/pedagogical terminology to aid with the understanding amongst these stakeholder groups. RESULTS: This review addresses CF-related IPC recommendations across five areas of university/college life, including (i) on campus estate, (ii) teaching (lectures/tutorials/small study group work/group assignments), (iii) laboratory practicals, (iv) field trips/study visits/work placements and (v) residential accommodation and lists practical recommendations to help prevent the transmission of infections to PwCF students. CONCLUSIONS: It is important that the educational institutional environment is safe permitting the PwCF student to enjoy their educational experience and journey through higher education, culminating in achievement of their educational goals, employment and independent living. The guidance presented in this review is intended to equip educational establishments in creating their own bespoke and robust IPC policies relating to PwCF students.

The Microbiology of Non-aeruginosa Pseudomonas Isolated From Adults With Cystic Fibrosis: Criteria to Help Determine the Clinical Significance of Non-aeruginosa Pseudomonas in CF Lung Pathology.

Introduction: There is a paucity of reports on non-aeruginosa Pseudomonas (NAPs) in cystic fibrosis, hence this study wished 1). to examine the diversity/frequency of NAPs in an adult CF population, 2) to compare/contrast the microbiology and genomics of NAPs to P. aeruginosa and 3) to propose clinical and laboratory criteria to help determine their clinical significance in CF lung pathology. Materials and Methods: Microbiological data was examined from 100 adult patients with cystic fibrosis from birth to present (31/12/2021), equating to 2455 patient years. 16S rDNA phylogenetic relatedness of NAPs was determined, as well as bioinformatical comparison of whole genomes of P. aeruginosa against P. fluorescens. Results: Ten species were isolated from this patient cohort during this time period, with three species, i.e., P. fluorescens, P. putida and P. stutzeri, accounting for the majority (87.5%) of non-aeruginosa reports. This is the first report of the isolation of P. fragi, P. nitroreducens, P. oryzihabitans and P. veronii in patients with cystic fibrosis. The mean time to first detection of any non-aeruginosa species was 183 months (15.25 years) [median = 229 months (19.1 years)], with a range from 11 months to 338 months (28.2 years). Several of the NAPs were closely related to P. aeruginosa. Discussion: NAPs were isolated infrequently and were transient colonisers of the CF airways, in those patients with CF in which they were isolated. A set of ten clinical and laboratory criteria are proposed to provide key indicators, as to the clinical importance of the non-aeruginosa species isolated.

Nebulizer Cleaning Practices and Adherence to Nebulized Therapies in People With Cystic Fibrosis When Traveling.

BACKGROUND: Nebulized therapies form an important component of treatment in people with cystic fibrosis (CF). It is important for people with CF to continue to take their nebulized medications when traveling. METHODS: A self-completing anonymous questionnaire was developed, as part of a quality improvement project, to support people with CF educational needs when traveling. The questionnaire was prepared to gain an insight into (1) adherence to nebulized therapies when traveling and (2) nebulizer cleaning and disinfection practices while traveling. Polar questions (yes/no response) were mainly employed as well as free text and closed questions. RESULTS: There were 68 respondents to the survey, including 31 males, 33 females, and 4 respondents who did not enter their sex. Respondents who declared their age (n = 63) ranged from 17-71 y (median = 30 y; with 94% of respondents in age range 20-39 y). When traveling, 38% (25/66) of respondents indicated that nebulized therapy was not performed during travel. The most common method of nebulizer maintenance while traveling was washing with soap and water (43%), followed by boiling water (18%), as well as the employment of 5 other methods of nebulizer maintenance. Some respondents (2%) indicated that they did not perform any method of nebulizer maintenance while traveling until they returned home. CONCLUSIONS: This study identified that nebulizer care and hygiene are less than optimal when traveling as well as identifying a worrying trend of taking a "nebulizer vacation." People with CF need to be aware of risks to their health in being nonadherent with their nebulized medication(s) while traveling as well as risks of acquiring a new pathogen through suboptimal cleaning/disinfection/drying management of their nebulizer. CF multidisciplinary teams should emphasize the importance of sustaining nebulized treatments when traveling and practicing effective nebulizer washing, disinfection, and drying procedures.

A doggy tale: Risk of zoonotic infection with Bordetella bronchiseptica for cystic fibrosis (CF) patients from live licenced bacterial veterinary vaccines for cats and dogs.

WHAT IS KNOWN AND OBJECTIVE: Live-attenuated bacterial veterinary vaccines can constitute an infection risk for individuals with any defect in their phagocytic function, including chronic granulomatous disease, leukocyte adhesion deficiency, myeloperoxidase deficiency, as well as Chediak-Higashi syndrome, from accidental acquisition of licenced attenuated live bacterial vaccine, at vaccination or from their vaccinated pet. Ownership of small companion animals, including cats and dogs, is popular within the cystic fibrosis (CF) community. These animals require vaccines as part of their routine care, which may involve live viral and bacterial vaccines, with potential for infection in the CF owner. This report examines the scope of current canine and feline vaccines, with particular emphasis on veterinary vaccination strategies against the Gram-negative pathogen, Bordetella bronchiseptica and describes new vaccine innovations offering protection to both pet and CF owner. COMMENT: The Gram-negative bacterium, Bordetella bronchoseptica, may cause respiratory disease in small companion animals, as well as in certain human vulnerable groups, including those with CF. Live licenced veterinary bacterial vaccines for Bordetella bronchiseptica (Kennel Cough) are available for cats and dogs, which are an infection concern for humans with CF who may come into contact with vaccinated animals. Live licenced veterinary bacterial vaccines for Bordetella bronchiseptica (Kennel Cough) are available for intranasal administration to cats and dogs. These vaccines require a withdrawal period of vaccinated animal from vulnerable owner, ranging from 35 days - 11 weeks. Recently, a new dead IM vaccine is now available not requiring exclusion of the vaccinated pet from CF owner. WHAT IS NEW & CONCLUSION: CF pharmacists, hospital pharmacists and community pharmacists are important custodians of vaccine-related advice to people with CF, who are frequently consulted for such advice. Pharmacists should be aware of the recent innovations in veterinary medicines, so that they can give appropriate advice to people with CF when asked. Immunocompromised patients, that is those with CF or those with any defect in their phagocytic function (chronic granulomatous disease, leukocyte adhesion deficiency, myeloperoxidase deficiency, Chediak-Higashi syndrome) should avoid exposure to live veterinary bacterial vaccines and seek animal vaccination utilising non-live vaccines. Most importantly, this manuscript highlights the development of a new veterinary vaccine for dogs, which we want to make the CF healthcare community aware of, which is an acellular dead vaccine, so that those patients with dogs needing annual vaccination can select this vaccine pathway, thereby minimising risk of infection from the vaccine strains and avoiding the social exclusion between CF patient and their pet. CF patients should understand the potential infection implications of live-attenuated viral and bacterial strains as vaccines, whether these are small companion animals, exotic animals or large farm animals. Patients should make their veterinarian aware of their CF status, so that a safe and efficacious vaccine strategy is used, both mitigating the potential infection risks from live vaccine components with the CF patient, but simultaneously offering maximum immunological protection to the animal.

Does Bordetella pertussis vaccine offer any cross-protection against Bordetella bronchiseptica? Implications for pet owners with cystic fibrosis.

WHAT IS KNOWN AND OBJECTIVE: The Gram-negative bacterium, Bordetella bronchiseptica, causes lower airway respiratory disease in people with cystic fibrosis (CF), as well as in companion animals, especially dogs. Presently, there are several acellular vaccines available for B. pertussis but no vaccine available for B. bronchiseptica. However given the shared protein homology between these two closely related species, we wished to explore whether pertussis vaccines may offer some cross-protection against B. bronchiseptica. COMMENT: Bordetella pertussis and B. bronchiseptica are closely related phylogenetically, as well as sharing protein homology in several pertussis vaccine components, including (i) pertussis toxin (PT), (ii) filamentous haemagglutinin (FHA), (iii) pertactin and (iv) fimbriae (types 2 and 3). Given that pertussis vaccine contains cross-reactive antigens with B. bronchiseptica, licensed pertussis vaccines may therefore offer cross-protection against B. bronchiseptica. WHAT IS NEW AND CONCLUSION: Cystic fibrosis pet owners should ensure that they have an up-to-date vaccination record relating to their pertussis vaccine. Although no monovalent human pertussis vaccines are currently available, licensed non-live booster vaccines for B. pertussis are available for individuals in the age range >10 years old. People with CF should ensure that they are adequately and currently protected against pertussis, to avoid whooping cough, which may also offer some cross-protection against B. bronchiseptica and therefore help further mitigate the risk of zoonotic infection of this organism from pets to their owners.

The virtual CF clinic: Implications for sputum microbiology.

The COVID19 pandemic has shifted the paradigm of how outpatient clinics are delivered within CF care, resulting in a significant reduction of patient visits to CF centres. One consequence of this has been a reduction in the number of sputa/cough swabs that patients submit for routine analysis. This report examines why it is important to maintain optimal sputum microbiology and explores (i). the microbiological efficiency of postal submission of sputum specimens from the community and (ii) the regulatory conditions that must be met through postal submission of respiratory specimens. Virtual clinics have now been established within CF care and it is incumbent on each speciality within the CF MDT to explore ways to nurture and support their individual contribution to the success of the virtual clinic. Within microbiology, adopting innovative approaches to sputum collection in the community and transportation via postal services will allow for continued microbiological vigilance thereby supporting patient safety.

Delafloxacin--A novel fluoroquinolone for the treatment of ciprofloxacin-resistant Pseudomonas aeruginosa in patients with cystic fibrosis.

INTRODUCTION: Fluoroquinolone antibiotics, namely ciprofloxacin and levofloxacin, play an important role in treating infection in cystic fibrosis (CF) and ciprofloxacin remains the last widely used and orally available antipseudomonal agent. Recently, a new fluoroquinolone, delafloxacin, has been approved by the FDA for the indication of Acute Bacterial Skin and Skin Structure Infections (ABSSSI). This antibiotic is a novel dual-targeting anionic fluoroquinolone and differs from previous agents in its class, as it lacks a protonatable substituent. To date, there are no reports of its use or activity against Pseudomonas aeruginosa in CF. Alarmingly, fluoroquinolone resistance is increasing among CF P aeruginosa isolates. The aims of the study were to (a) examine in vitro susceptibility of delafloxacin against a population of P. aeruginosa (n = 52) isolated from adult CF patients at our CF centre, (b) to compare delafloxacin and ciprofloxacin in vitro susceptibilities against CF P. aeruginosa and (c) to evaluate where delafloxacin may add benefit in treating CF P aeruginosa. METHODS: In vitro susceptibilities were examined on 52 non-mucoid P. aeruginosa and P. aeruginosa ATCC™ 27853 reference strain, by employing Etest® gradient test strips for delafloxacin (range:0.002 - 32 mg/L) and ciprofloxacin (0.002 - 32 mg/L), as per manufacturer's instructions (Biomerieux). RESULTS: MIC range, MIC50 and MIC90 for delafloxacin were 0.064 â†’ 32 mg/L, 0.56 mg/L and 2.19 mg/L, respectively. For ciprofloxacin, these were 0.047 â†’ 32 mg/L, 1.69 mg/L and 8.0 mg/L, respectively. Overall, isolates were statistically more sensitive to delafloxacin (p = 0.0005) than ciprofloxacin. Of note, 4/12 (33.3%) isolates with intermediate resistance to ciprofloxacin were sensitive to delafloxacin. Similarly, 10/28 (35.7%) isolates resistant to ciprofloxacin were sensitive to delafloxacin, with only 17.9% isolates resistant to ciprofloxacin, resistant to delafloxacin. CONCLUSION: Given similar breakpoints of these fluoroquinolones, these data show that delafloxacin has greater activity than ciprofloxacin. While delafloxacin and ciprofloxacin were equally effective with sensitive isolates, the value of delafloxacin was noted with more resistant isolates to ciprofloxacin. While ciprofloxacin should remain the first line fluoroquinolone for treating CF P aeruginosa, delafloxacin shows potential in treating ciprofloxacin-resistant P aeruginosa.

Who's at The Door? - Surface Contamination of Door Frames in a Single-Bedded In-Patient Adult Cystic Fibrosis (CF) Unit.

The Gram-negative bacterium, Pseudomonas aeruginosa, is a major respiratory pathogen in patients with cystic fibrosis (CF), with an associated increase in morbidity and mortality. Consequently, infection prevention and control (IPC) plays an important role within health care in order to minimize the risk of cross-infection of this organism amongst patients and the hospital environment. It was the aim of this study to examine bacterial contamination of the health estate of CF in-patients' single-bedded rooms and related environments (n=40). Twelve bacterial genera were identified, six being Gram-positive (Brevibacterium, Dermacoccus, Micrococcus, Rothia, Staphylococcus and Streptococcus), and six being Gram-negative (Acinetobacter, Citrobacter, Klebsiella, Moraxella, Pantoea and Pseudoxanthomonas). None of the organisms identified were considered of particular clinical significance to CF patients. The CF lung and associated sputa may be important reservoirs of Pseudomonas aeruginosa, with potential for spill-over into the health care estate. In the aftermath of the Pseudomonas neonatal outbreak at Altnagelvin and the Royal Jubilee Maternity Hospitals, where there was heightened IPC awareness regarding the presence of this bacterium, it is encouraging to note its absence from the CF-health care estate examined.

"Pathogen Eradication" and "Emerging Pathogens": Difficult Definitions in Cystic Fibrosis.

Infection is a common complication of cystic fibrosis (CF) airway disease. Current treatment approaches include early intervention with the intent to eradicate pathogens in the hope of delaying the development of chronic infection and the chronic use of aerosolized antibiotics to suppress infection. The use of molecules that help restore CFTR (cystic fibrosis transmembrane conductance regulator) function, modulate pulmonary inflammation, or improve pulmonary clearance may also influence the microbial communities in the airways. As the pipeline of these new entities continues to expand, it is important to define when key pathogens are eradicated from the lungs of CF patients and, equally important, when new pathogens might emerge as a result of these novel therapies.

In vitro activity of seven hospital biocides against Mycobacterium abscessus: Implications for patients with cystic fibrosis.

Background: Mycobacterium abscessus pulmonary infection has recently emerged as a significant pathogen in patients with cystic fibrosis (CF) and is associated with significant morbidity and accelerated pulmonary decline. There is a paucity of data describing the activity of hospital biocides against this organism. Methods: M. abscessus isolates (n = 13) were recovered from CF and non-CF respiratory specimens. Seven commonly employed hospital biocides with generic ingredients as follows: acetone, propan-2-ol, diethylene glycol, 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one, chlorine dioxide, 4% chlorhexidine, alcohol, and disodium carbonate, compound with hydrogen peroxide, 10% sodium hypochlorite were assayed for their biocidal activity against M. abscessus. Fresh cultures of M. abscessus were exposed to biocide in liquid medium as per manufacturers' instruction and were immediately plated following the completion of the contact period. The mean concentration of M. abscessus plated was 9.82 × 106 colony-forming units (range: 1.63 × 105-1.12 × 108). In addition, the remaining bacteria/biocide solution was enriched nonselectively in Mueller Hinton broth (37°C/1 week) and then plated. Results: All M. abscessus isolates survived in alkyl dimethyl benzyl ammonium chloride, 5-chloro-2-methyl-2H-isothiazol-3-one (EC No. 247-500-7) and 2-methyl-2H-isothiazol-3-one, 4% Chlorhexidine™, O-phenylphenol and Sodium Lauryl Sulfate™ and disodium carbonate, compound with hydrogen peroxide. One out of 13 M. abscessus cultures was killed by Chlorine Dioxide™ and one by Sodium Dichloroisocyanurate™, representing a 5-log kill. Two isolates were killed by Alcohol™ again representing a 5 log kill. Following enrichment, O-phenylphenol and Sodium Lauryl Sulfate™ showed the greatest biocidal activity with 11/13 isolates, whereas 2/13 cultures were killed by sodium dichloroisocyanurate™. All other biocide/culture combinations yielded growth. Conclusion: These data indicate that M. abscessus may persist after exposure to several common hospital biocides. Further work is urgently needed to define unequivocal biocide contact treatments to prevent cross-infection with this mycobacterial species in this patient population and thus ensure effective infection control and prevention.

MRSA eradication of newly acquired lower respiratory tract infection in cystic fibrosis.

UK cystic fibrosis (CF) guidelines recommend eradication of methicillin-resistant Staphylococcus aureus (MRSA) when cultured from respiratory samples. As there is no clear consensus as to which eradication regimen is most effective, we determined the efficacy of eradication regimens used in our CF centre and long-term clinical outcome. All new MRSA positive sputum cultures (n=37) that occurred between 2000 and 2014 were reviewed. Eradication regimen characteristics and clinical, microbiological and long-term outcome data were collected. Rifampicin plus fusidic acid was the most frequently used regimen (24 (65%) out of 37 patients), with an overall success rate of 79% (19 out of 24 patients). Eradication failure was more likely in patients with an additional MRSA-positive peripheral screening swab (p=0.03) and was associated with worse survival (p=0.04). Our results demonstrate the feasibility and clinical benefits of MRSA eradication. As peripheral colonisation was associated with lower eradication success, strategies combining systemic and topical treatments should be considered to optimise outcomes in CF patients.

Survival dynamics of cystic fibrosis-related Gram-negative bacterial pathogens (Pseudomonas aeruginosa and Burkholderia cenocepacia) in Dead Sea and Atlantic Ocean waters.

Clinical cystic fibrosis (CF) Pseudomonas aeruginosa (n=6) and Burkholderia cenocepacia (n=4) were inoculated in marine brines from the Dead Sea and the Atlantic Ocean and their survival was monitored over a 1 month duration. In Dead Sea samples, all P. aeruginosa and B. cenocepacia isolates were non-detectable by culture following 24 h incubation, including the non-selective enrichment samples. In the Atlantic Ocean brine, over a 1 month period, mean P. aeruginosa counts decreased by only 0.25 log10 units and mean B. cenocepacia counts decreased by approximately 4 log10 units (10,000 cfu/ml). This study demonstrated that Dead Sea brine exerted a lethal effect within 24 h on planktonic P. aeruginosa and B. cenocepacia. Thus, the Dead Sea effectively purges these organisms from its environment on a daily basis.