A protracted outbreak of difficult-to-treat resistant Pseudomonas aeruginosa in a haematology unit: a matched case-control study demonstrating increased risk with use of fluoroquinolone

BACKGROUND

Between September 2016 and November 2020, 17 cases of difficult-to-treat resistant Pseudomonas aeruginosa (DTR-PA) were reported in haematology patients at a tertiary referral hospital in the North of England.

AIM

A retrospective case-control study was conducted to investigate the association between DTR-PA infection and clinical interventions, patient movement, antimicrobial use and comorbidities.

METHODS

Cases were patients colonized or infected with the outbreak strain of DTR-PA who had been admitted to hospital prior to their positive specimen. Exposures were extracted from medical records, and cases were compared with controls using conditional logistic regression. Environmental and microbiological investigations were also conducted.

FINDINGS

Seventeen cases and 51 controls were included. The final model included age [>65 years, adjusted OR (aOR) 6.85, P=0.232], sex (aOR 0.60, P=0.688), admission under the transplant team (aOR 14.27, P=0.43) and use of ciprofloxacin (aOR 102.13, P=0.030). Investigations did not indicate case-to-case transmission or a point source, although a common environmental source was highly likely.

CONCLUSION

This study found that the use of fluoroquinolones is an independent risk factor for DTR-PA in haematology patients. Antimicrobial stewardship and review of fluoroquinolone prophylaxis should be considered as part of PA outbreak investigations in addition to standard infection control interventions.

Circulation of a community healthcare-associated multiply-resistant meticillin-resistant Staphylococcus aureus lineage in South Yorkshire identified by whole genome sequencing

BACKGROUND

A cluster of seven cases of skin and wound infections caused by a multiply resistant meticillin-resistant Staphylococcus aureus (MRSA) were detected in a small-town community in South Yorkshire. Initial microbiological investigations showed that all isolates belonged to a spa type observed rarely in England (t1476).

AIM

To describe the epidemiology of t1476 MRSA in South Yorkshire.

METHODS

Retrospective and prospective case ascertainment was promoted through communication with local microbiology laboratories. Public health investigation included a detailed review of clinical notes for a subset of nine cases. Genomic and phylogenetic analysis was undertaken on t1476 MRSA.

FINDINGS

Thirty-two cases of t1476 MRSA infection or colonization were identified between December 2014 and February 2018. Cases were older adults (aged 50-98 years). Healthcare exposures for a subset of nine cases indicated frequent contact with a team of district nurses, with all but one case receiving treatment on the same day as another case prior to their own diagnosis. No cases were admitted to hospital at the time of specimen collection. Despite detailed investigations, no carriers were detected among district nursing staff. A long-term carrier/super-shedder was not found. Phylogenetic analysis indicated that t1476 MRSA cases from South Yorkshire were monophyletic and distant from both MRSA of the same lineage from elsewhere in the UK (N = 15) and from publicly available sequences from Tanzania.

CONCLUSION

Genomic and epidemiological analyses indicate community-based transmission of a multiply resistant MRSA clone within South Yorkshire introduced around 2012-2013, prior to the detection of a spatial-temporal cluster associated with a distinct risk group. Surveillance data indicate continued circulation.

Intravenous fosfomycin for pulmonary exacerbation of cystic fibrosis: Real life experience of a large adult CF centre

BACKGROUND

The increased prevalence of multi-drug resistant strains of P.aeruginosa and allergic reactions among adult patients with cystic fibrosis (CF) limits the number of antibiotics available to treat pulmonary exacerbations. Fosfomycin, a unique broad spectrum bactericidal antibiotic, might offer an alternative therapeutic option in such cases.

AIM

To describe the clinical efficacy, safety and tolerability of intravenous fosfomycin in combination with a second anti-pseudomonal antibiotic to treat pulmonary exacerbations in adult patients with CF.

METHOD

A retrospective analysis of data captured prospectively, over a 2-years period, on the Unit electronic medical records for patients who received IV fosfomycin was performed. Baseline characteristics in the 12 months prior treatment, lung function, CRP, renal and liver function and electrolytes at start and end of treatment were retrieved.

RESULTS

54 patients received 128 courses of IV fosfomycin in combination with a second antibiotic, resulting in improved FEV1 (0.94 L vs 1.24 L, p < 0.01) and reduced CRP (65 mg/L vs 19.3 mg/L, p < 0.01). Renal function pre- and post-treatment remained stable. 4% (n = 5) of courses were complicated with AKI at mid treatment, which resolved at the end of the course. Electrolyte supplementation was required in 18% of cases for potassium and magnesium and 7% for phosphate. Nausea was the most common side effect (48%), but was well controlled with anti-emetics.

CONCLUSION

Antibiotic regimens including fosfomycin appear to be clinically effective and safe. Fosfomycin should, therefore, be considered as an add-on therapy in patients who failed to respond to initial treatment and with multiple drug allergies.

Rat Cytomegalovirus Vaccine Prevents Accelerated Chronic Rejection in CMV-Naïve Recipients of Infected Donor Allograft Hearts

Cytomegalovirus accelerates transplant vascular sclerosis (TVS) and chronic rejection (CR) in solid organ transplants; however, the mechanisms involved are unclear. We determined the efficacy of a CMV vaccine in preventing CMV-accelerated rat cardiac allograft rejection in naïve recipients of CMV+ donor hearts. F344 donor rats were infected with RCMV 5 days prior to heterotopic cardiac transplantation into CMV-naïve or H2 O2 -inactivated RCMV-vaccinated Lewis recipients. Recipients of RCMV-infected donor hearts rejected at POD59, whereas vaccinated recipients exhibited a significantly prolonged time to rejection-POD97, similar to recipients of uninfected donor hearts (POD108). Although all of the donor hearts were preinfected, the vaccinated recipients had lower graft and PBMC viral loads at POD 7 compared to unvaccinated controls. Adoptive T cell and passive antibody transfers from vaccinated Lewis rats into naïve recipients demonstrate that both T-cell and B-cell arms of the adaptive immune response provide protection against CMV-accelerated rejection. Similar findings were obtained when testing three different adjuvants in passive transfer experiments. We have determined that the timing of the vaccine prior to transplantation and the specific adjuvant play critical roles in mediating anti-viral responses and promoting graft survival. CMV vaccination prior to transplantation may effectively increase graft survival.

Fungal contamination of nebuliser devices used by people with cystic fibrosis

BACKGROUND

Poor nebuliser hygiene can result in bacterial contamination and risk of infections. The aim of this study was to assess the prevalence of fungal contamination of nebulisers used by adults with cystic fibrosis.

METHODS

A total of 170 nebulisers from 149 subjects were screened by wetting a sterile cotton swab with sterile water and swabbing each drug chamber. The swab was then plated out on Sabouraud and on Scel+agar and incubated at 27 °C for up to 2 weeks.

RESULTS

Fungal cultures were positive in 86 (57.7%) patient's devices. In 28/149 (18.8%), 39/149 (26.2%), 47/149 (31.5%) and 20/149 (13.4%) of subjects Aspergillus species, yeasts, moulds and both yeasts and moulds were isolated respectively. There was no difference in contamination rates between different devices.

CONCLUSION

Nebuliser devices are frequently contaminated by moulds and yeasts and emphasis should be placed on ensuring adequate nebuliser hygiene.

Twenty-year survivors of kidney transplantation

There have been few studies of patients with renal allografts functioning for more than 20 years. We sought to identify clinical factors associated with ultra long-term (>20 year) renal allograft survival and to describe the clinical features of these patients. We performed a retrospective analysis of the Irish Renal Transplant Database and included 1174 transplants in 1002 patients. There were 255 (21.74%) patients with graft function for 20 years or more. Multivariate analysis identified recipient age (HR 1.01, CI 1.01-1.02), gender (male HR 1.25, CI 1.08-1.45), acute rejection (HR 1.26, CI 1.09-1.45) and transplant type (living related donor vs. deceased donor) (HR 0.52, CI 0.40-0.66) as significantly associated with long-term graft loss. Median serum creatinine was 115 μmol/L. The 5-year graft survival in 20-year survivors was 74.7%. The mean age at death was 62.7 years (±10.6). The most common causes of death were cardiovascular disease and malignancy. The two major causes of graft loss were death (with function) and interstitial fibrosis/tubular atrophy. Comorbidities included skin cancer (36.1%), coronary heart disease (17.3%) and other malignancies (14.5%). This study identifies factors associated with long-term allograft survival and a high rate of morbidity and early mortality in long-term transplant recipients.

Antibiotic Treatment of Multidrug-Resistant Organisms in Cystic Fibrosis

Respiratory tract infection with eventual respiratory failure is the major cause of morbidity and mortality in cystic fibrosis (CF). Infective exacerbations need to be treated promptly and effectively to minimize potentially accelerated attrition of lung function. The choice of antibiotic depends on in vitro sensitivity patterns. However, physicians treating patients with CF are increasingly faced with infection with multidrug-resistant isolates of Pseudomonas aeruginosa. In addition, innately resistant organisms such as Burkholderia cepacia complex, Stenotrophomonas maltophilia and Achromobacter (Alcaligenes) xylosoxidans are becoming more prevalent. Infection with methicillin-resistant Staphylococcus aureus (MRSA) is also a problem. These changing patterns probably result from greater patient longevity and increased antibiotic use for acute exacerbations and maintenance care. Multidrug-resistant P. aeruginosa infection may be treated successfully by using two antibiotics with different mechanisms of action. In practice antibiotic choices have usually been made on a best-guess basis, but recent research suggests that more directed therapy can be achieved through the application of multiple-combination bactericidal testing (MCBT). Aerosol delivery of tobramycin for inhalation solution achieves high endobronchial concentrations that may overcome bacterial resistance as defined by standard laboratory protocols. Resistance to colistin is rare and this antibiotic should be seen as a valuable second-line drug to be reserved for multidrug-resistant P. aeruginosa. The efficacy of new antibiotic groups such as the macrolides needs to be evaluated.CF units should adopt strict segregation policies to interrupt person-to-person spread of B. cepacia complex. Treatment of panresistant strains is difficult and often arbitrary. Combination antibiotic therapy is recommended, usually tobramycin and high-dose meropenem and/or ceftazidime, but the choice of treatment regimen should always be guided by the clinical response.The clinical significance of S. maltophilia, A. xylosoxidans and MRSA infection in CF lung disease remains uncertain. If patients show clinical decline and are chronically colonized/infected with either of the former two pathogens, treatment is recommended but efficacy data are lacking. There are defined microbiological reasons for attempting eradication of MRSA but there are no proven deleterious effects of this infection on lung function in patients with CF. Various treatment protocols exist but none has been subject to a randomized, controlled trial. Multidrug-resistant microorganisms are an important and growing issue in the care of patients with CF. Each patient infected with such strains should be assessed individually and antibiotic treatment planned according to in vitro sensitivity, patient drug tolerance, and results of in vitro studies which may direct the physician to antibiotic combinations most likely to succeed.

Social determinants of older adults' awareness of community support services in Hamilton, Ontario

Community support services (CSSs) have been developed in Canada and other Western nations to enable persons coping with health or social issues to continue to live in the community. This study addresses the extent to which awareness of CSSs is structured by the social determinants of health. In a telephone interview conducted in February-March 2006, 1152 community-dwelling older adults (response rate 12.4%) from Hamilton, Ontario, Canada were made to read a series of four vignettes and were asked whether they were able to identify a CSS they may turn to in that situation. Across the four vignettes, 40% of participants did name a CSS as a possible source of assistance. Logistic regression was used to determine factors related to awareness of CSSs. Respondents most likely to have awareness of CSS include the middle-aged and higher-income groups. Being knowledgeable about where to look for information about CSSs, having social support and being a member of a club or voluntary organisations are also significant predictors of awareness of CSSs. Study results suggest that efforts be made to improve the level of awareness and access to CSSs among older adults by targeting their social networks as well as their health and social care providers.

Pleuroperitoneal leak complicating peritoneal dialysis: a case series

Pressure related complications such as abdominal wall hernias occur with relative frequency in patients on peritoneal dialysis. Less frequently, a transudative pleural effusion containing dialysate can develop. This phenomenon appears to be due to increased intra-abdominal pressure in the setting of congenital or acquired diaphragmatic defects. We report three cases of pleuroperitoneal leak that occurred within a nine-month period at our institution. We review the literature on this topic, and discuss management options. The pleural effusion resolved in one patient following drainage of the peritoneum and a switch to haemodialysis. One patient required emergency thoracocentesis. The third patient developed a complex effusion requiring surgical intervention. The three cases highlight the variability of this condition in terms of timing, symptoms and management. The diagnosis of a pleuroperitoneal leak is an important one as it is managed very differently to most transudative pleural effusions seen in this patient population. Surgical repair may be necessary in those patients who wish to resume peritoneal dialysis, or in those patients with complex effusions. Pleuroperitoneal leak should be considered in the differential diagnosis of a pleural effusion, particularly a right-sided effusion, in a patient on peritoneal dialysis.

Isolation of the fungus Geosmithia argillacea in sputum of people with cystic fibrosis

We report the repeated isolation of the fungus Geosmithia argillacea from sputum samples of people with cystic fibrosis. Identification was based on morphology and DNA sequence analysis. Isolation of G. argillacea did not appear to be associated with clinical deterioration. The pathogenic potential of G. argillacea is discussed.

Where would you turn for help? Older adults' awareness of community support services

Previous findings on older adults' awareness of community support services (CSSs) have been inconsistent and marred by acquiescence or over-claiming bias. To address this issue, this study used a series of 12 vignettes to describe common situations faced by older adults for which CSSs might be appropriate. In telephone interviews, 1,152 adults aged 50 years and over were read a series of vignettes and asked if they were able to identify a community organization or agency that they may turn to in that situation. They were also asked about their most important sources of information about CSSs. The findings show that, using a vignette methodology, awareness of CSSs is much lower than previously thought. The most important sources of information about CSSs included information and referral sources, the telephone book, doctors' offices, and word of mouth.

The EPISA study: antimicrobial susceptibility of Staphylococcus aureus causing primary or secondary skin and soft tissue infections in the community in France, the UK and Ireland

OBJECTIVES

To provide information on the susceptibility of Staphylococcus aureus causing skin and soft tissue infections (SSTIs) in France, Ireland and the UK.

PATIENTS AND METHODS

One thousand three hundred and ninety patients attending their general practitioners for skin infections were recruited. Susceptibility to 11 antimicrobials using CLSI (formerly NCCLS) broth microdilution was determined for 646 S. aureus isolates detected in the evaluable patient population.

RESULTS

Susceptibility results were similar in the UK and Ireland, but differed in France. The largest difference between countries was observed for erythromycin and fusidic acid. In France, 67.8% of isolates were susceptible to erythromycin when compared with 88.6% in Ireland and 92.8% in the UK. However, 93.7% of French isolates were susceptible to fusidic acid, compared with 68.6% in Ireland and 75.6% in the UK. A diagnosis of impetigo was associated with reduced fusidic acid susceptibility.

CONCLUSIONS

Differences in the prevalence of certain diagnoses, particularly impetigo, rather than differences in antibiotic consumption may explain some of the observed differences in susceptibility seen between these countries.