Elimination of Australian epidemic strain (AES1) pseudomonas aeruginosa in a pediatric cystic fibrosis center

Infection prevention and control in cystic fibrosis: An update of a systematic review of interventions

Preventing transmissible infection is a priority in cystic fibrosis (CF) care. This is an update of a systematic review of the evidence for infection prevention and control interventions in CF. Our full protocol can be found on PROSPERO (CRD42018109999). We searched for studies and guidelines which included interventions for infection prevention and control in CF. We included 39 studies and 7 guidelines. Strategies included: cohort or individual segregation, hand hygiene, facemasks, equipment, enhanced adherence or a combination of these. Many studies showed a reduction in transmission with segregation. However, the certainty of evidence (using GRADE) was low or very low. Most guideline recommendations have little evidence to support them, with no updates since our original review. Undertaking RCTs in this area is ethically difficult. Large-scale registry-based studies may be the best pragmatic approach. Benefits of infection control must be balanced against the intrusion in the lives of people with CF.

Investigating Pseudomonas aeruginosa population structure and frequency of cross-infection in UK cystic fibrosis clinics - a reference laboratory perspective

BACKGROUND

We aimed to describe the UK Pseudomonas aeruginosa population structure amongst people with cystic fibrosis (PWCF), and to examine evidence for cross-infection.

METHODS

Variable Number Tandem Repeat (VNTR) typing was performed on 4640 isolates from 2619 PWCF received from 55 hospital laboratories between 2017 and 2019. A combination of whole genome sequence (WGS)-based analysis of four clusters from one hospital, and epidemiological analysis of shared strains in twelve hospitals evaluated cross-infection.

RESULTS

Of 2619 PWCF, 1324 (51%) harboured common clusters or known transmissible strains, while 1295 carried unique strains/those shared among small numbers of patients. Of the former, 9.5% (250 patients) harboured the Liverpool epidemic strain (LES), followed in prevalence by clone C (7.8%; 205 patients), cluster A (5%;130 patients), and cluster D (3.6%; 94 patients). WGS analysis of 10 LES isolates, 9 of cluster D and 6 isolates each of cluster A and clone C from one hospital revealed LES formed the tightest cluster (between 7 and 205 SNPs), and cluster D the loosest (between 53 and 1531 SNPs). Hospital-specific shared strains were found in some centres, although cross-infection was largely historical, with few new acquisitions. Fifty-nine PWCF (2.3%) harboured "high-risk" clones; one ST235 isolate carried a blaIMP-1 allele.

CONCLUSION

Of 2619 PWCF who had P. aeruginosa isolates submitted for VNTR, 51% harboured either common clusters or known transmissible strains, of which LES was the most common. Limited evidence of recent patient-to-patient strain transmission was found, suggesting cross-infection prevention measures and surveillance effectively reduce transmission.

Current and Emerging Therapies to Combat Cystic Fibrosis Lung Infections

The ultimate aim of any antimicrobial treatment is a better infection outcome for the patient. Here, we review the current state of treatment for bacterial infections in cystic fibrosis (CF) lung while also investigating potential new treatments being developed to see how they may change the dynamics of antimicrobial therapy. Treatment with antibiotics coupled with regular physical therapy has been shown to reduce exacerbations and may eradicate some strains. Therapies such as hypertonic saline and inhaled PulmozymeTM (DNase-I) improve mucus clearance, while modifier drugs, singly and more successfully in combination, re-open certain mutant forms of the cystic fibrosis transmembrane conductance regulator (CFTR) to enable ion passage. No current method, however, completely eradicates infection, mainly due to bacterial survival within biofilm aggregates. Lung transplants increase lifespan, but reinfection is a continuing problem. CFTR modifiers normalise ion transport for the affected mutations, but there is conflicting evidence on bacterial clearance. Emerging treatments combine antibiotics with novel compounds including quorum-sensing inhibitors, antioxidants, and enzymes, or with bacteriophages, aiming to disrupt the biofilm matrix and improve antibiotic access. Other treatments involve bacteriophages that target, infect and kill bacteria. These novel therapeutic approaches are showing good promise in vitro, and a few have made the leap to in vivo testing.

Current infection control practices used in Australian and New Zealand cystic fibrosis centers

BACKGROUND

The 2013 update of the Infection Prevention and Control (IP&C) Guideline outlined recommendations to prevent the spread of CF respiratory pathogens. We aimed to investigate the current infection control practices used in Australian and New Zealand (NZ) CF centers.

METHODS

Two online surveys were distributed to Australian and NZ CF centers regarding the uptake of selected IP&C recommendations. One survey was distributed to all the Medical Directors and Lead CF Nurses and the second survey was distributed to all the Lead CF Physiotherapists.

RESULTS

The response rate was 60% (60/100) for medical/nursing and 58% (14/24) for physiotherapy. Over 90% (55/60) of CF centers followed CF-specific infection control guidelines and consistent infection control practices were seen in most CF centers; 76% (41/54) had implemented segregation strategies for ambulatory care and no CF centers housed people with CF in shared inpatient accommodation. However, the application of contact precautions (wearing gloves and apron/gown) by healthcare professionals when reviewing a CF person was variable between CF center respondents but was most often used when seeing CF persons with MRSA infection in both ambulatory care and hospital admission (20/50, 40% and 42/45, 93% of CF centers, respectively). Mask wearing by people with CF was implemented into 61% (36/59) of centers. Hospital rooms were cleaned daily in 79% (37/47) of CF centers and the ambulatory care consult rooms were always cleaned between consults (49/49, 100%) and at the end of the clinic session (51/51, 100%); however the staff member tasked with cleaning changed with 37% (18/49) of CF centers responding that CF multidisciplinary team (MDT) members cleaned between patients whereas at the end of the clinic session, only 12% (6/51) of the CF MDT cleaned the consult room.

CONCLUSIONS

Overall, Australian and NZ CF centers have adopted many recommendations from the IP&C. Although, the application of contact precautions was inconsistent and had overall a low level of adoption in CF centers. In ~ 25% of centers, mixed waiting areas occurred in the ambulatory care. Given the variability of responses, additional work is required to achieve greater consistency between centers.

Toothbrushes may convey bacteria to the cystic fibrosis lower airways

Recent findings indicate that the oral cavity acts as a bacterial reservoir and might contribute to the transmission of bacteria to the lower airways. Control of a potentially pathogenic microbiota might contribute to prevent the establishment of chronic infection in cystic fibrosis. We evaluated the presence of CF microorganisms in saliva and toothbrushes of CF patients and verify their possible transmission to lower airways. Methods: We assessed the presence of P. aeruginosa, S. aureus, S. maltophilia, A. xylosoxidans, S. marcescens, and yeasts in saliva, toothbrushes and sputum of 38 CF patients and assessed the clonal identity of the strains occurring contemporary in multiple sites by PFGE. Results: At least one of the investigated species was isolated from 60 saliva samples and 23 toothbrushes. S. aureus was the most abundant species, followed by Candida spp. 31 patients contemporary had the same species in sputum and saliva/toothbrush: in most cases, clonal identity of the strains among the different sites was confirmed. Conclusion: Toothbrushes may be sources of oral contamination and might act as reservoirs favoring transmission of potentially pathogenic microorganisms from the environment to the oral cavity and eventually to the LAW. Oral hygiene and toothbrush care are important strategies to prevent CF lung infections.

Cystic fibrosis year in review 2018, part 1

Cystic fibrosis research and case reports were robust in the year 2018. This report summarizes research and cases related to Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) modulator therapies, inflammation and infection, epidemiology and the physiologic, and imaging assessment of disease.

Pulsed-field gel electrophoresis (PFGE): A review of the "gold standard" for bacteria typing and current alternatives

Pulsed-field gel electrophoresis (PFGE) is considered the "gold standard" for bacteria typing. The method involves enzyme restriction of bacteria DNA, separation of the restricted DNA bands using a pulsed-field electrophoresis chamber, followed by clonal assignment of bacteria based on PFGE banding patterns. Various PFGE protocols have been developed for typing different bacteria, leading it to be one of the most widely used methods for phylogenetic studies, food safety surveillance, infection control and outbreak investigations. On the other hand, as PFGE is lengthy and labourious, several PCR-based typing methods can be used as alternatives for research purposes. Recently, matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) and whole genome sequencing (WGS) have also been proposed for bacteria typing. In fact, as WGS provides more information, such as antimicrobial resistance and virulence of the tested bacteria in comparison to PFGE, more and more laboratories are currently transitioning from PFGE to WGS for bacteria typing. Nevertheless, PFGE will remain an affordable and relevant technique for small laboratories and hospitals in years to come.