Course and outcome of Staphylococcus aureus bacteraemia: a retrospective analysis of 308 episodes in a Swiss tertiary-care centre

Staphylococcus aureus bacteraemia (SAB) is associated with substantial morbidity and mortality worldwide. The charts of adult patients with SAB who were hospitalised in a Swiss tertiary-care centre between 1998 and 2002 were studied retrospectively. In total, 308 episodes of SAB were included: 2% were caused by methicillin-resistant strains; 49% were community-acquired; and 51% were nosocomial. Bacteraemia without focus was the most common type of community-acquired SAB (52%), whereas intravenous catheter-related infection predominated (61%) among nosocomial episodes of SAB. An infectious diseases (ID) specialist was consulted in 82% of all cases; 83% received appropriate antibiotic treatment within 24 h of obtaining blood cultures. Overall hospital-associated mortality was 20%. Community-acquired SAB was associated independently with a higher mortality rate than nosocomial SAB (26% vs. 13%; p 0.009). Independent risk-factors for a fatal outcome were age (p < 0.001), immunosuppression (p 0.007), alcoholism (p < 0.001), haemodialysis (p 0.03), acute renal failure (p < 0.001) and septic shock (p < 0.001). Consultation with an ID specialist was associated with a better outcome in univariate analysis (p < 0.001). Compared with a previous retrospective analysis performed at the same institution between 1980 and 1986, there was a 140% increase in community-acquired SAB, a 60% increase in catheter-related SAB, and a 14% reduction in mortality. In conclusion, mortality in patients with SAB remained high, despite effective antibiotic therapy. Patients with community-acquired SAB were twice as likely to die as patients with nosocomial SAB. Consultation with an ID specialist may reduce mortality in patients with SAB.     

Oral infections and systemic disease—an emerging problem in medicine

The relationship between oral and general health has been increasingly recognised during the past two decades. Several epidemiological studies have linked poor oral health with cardiovascular disease, poor glycaemic control in diabetics, low birth-weight pre-term babies, and a number of other conditions, including rheumatoid arthritis and osteoporosis. Oral infections are also recognised as a problem for individuals suffering from a range of chronic conditions, including cancer and infection with human immunodeficiency virus, as well as patients with ventilator-associated pneumonia. This review considers the systemic consequences of odontogenic infections and the possible mechanisms by which oral infection and inflammation can contribute to cardiovascular disease, as well as the oral conditions associated with medically compromised patients. A large number of clinical studies have established the clinical efficacy of topical antimicrobial agents, e.g., chlorhexidine and triclosan, in the prevention and control of oral disease, especially gingivitis and dental plaque. The possible risks of antimicrobial resistance are a concern, and the benefits of long-term use of triclosan require further evaluation. Oral infections have become an increasingly common risk-factor for systemic disease, which clinicians should take into account. Clinicians should increase their knowledge of oral diseases, and dentists must strengthen their understanding of general medicine, in order to avoid unnecessary risks for infection that originate in the mouth.     

Antimicrobial treatment of invasive non-perinatal human listeriosis and the impact of the underlying disease on prognosis

Listeriosis is a resurgent foodborne disease in European countries. Benefits of combined β-lactam-aminoglycoside treatment remain controversial and the impact of the underlying disease on prognosis has not been fully assessed. We conducted a retrospective review of cases of sporadic listeriosis in adults from 1995 to 2008 at two university-affiliated hospitals serving a population of 600 000 people in Madrid, Spain. The primary end-point was the associated in-hospital mortality. Sixty-four patients were studied. Estimated incidence of listeriosis was 0.76/100.000 persons/year. Seventy-four per cent had chronic underlying diseases; cirrhosis of the liver and haematologi-cal and solid neoplasias were the most common comorbidities. Primary bacteraemia (58%) and meningitis (42%) were the most frequent manifestations. Focal infections were seen in ten cases. In-hospital mortality was 31%. Patients treated with ampicillin or with an ampicillin-gentamicin combination did not differ in age, severity of underlying disease or type of presentation. Differences in mortality were not seen between patients treated with monotherapy and those given combined treatment (28% vs 35%; p 0.634). Ten patients were treated with trimethoprim-sulfamethozaxole alone and only one died. All patients without comorbidities survived infection but mortality of patients with cirrhosis of the liver was 21% and that of patients with haematological or solid neoplasias was 66%. Only haematological neoplasia (OR 6.67; 95% CI 1.71-26.04; p 0.006) was significantly associated with an increased risk of mortality (R²_Cox-Snell= 0.262). Mortality of listeriosis mainly depended on the severity of the underlying disease. Combined ampicillin-gentamicin therapy did not improved survival. Trimethoprim-sulfamethozaxole may be an effective alternative therapy for listerial infections.     

Risk-adjusted comparisons of bloodstream infection rates in neonatal intensive-care units

Comparisons of bloodstream infection (BSI) rates between neonatal intensive-care units (NICUs) should take into account differences in babies' vulnerability and invasive procedures that can introduce infection. Our aim was to investigate which risk factors recorded in routine records should be adjusted for when NICUs are compared. This was a retrospective cohort study using routine records for two London NICUs. We analysed rates of BSI with Poisson regression models. The level of neonatal care used by the National Health Service was the strongest predictor of BSI incidence. The rate ratios for BSI, adjusted for birthweight, inborn/outborn status, and postnatal age, were 3.15 (95% CI 2.01–4.94) for intensive care and 6.58 (95% CI 4.18-10.36) for high-dependency care, relative to special care. Total parenteral nutrition was significantly associated with BSI incidence, but explained less of the variance among babies than level of care. A case—control study with the same dataset gave similar results. Further multicentre studies are required to confirm our predictive model. Until then, we recommend that comparisons of BSI rates between NICUs should include adjustments for level of care, birthweight, inborn/outborn status, and postnatal age, with the use of routinely recorded standardized measures in hospital administrative data.     

Epidemiologic changes in bloodstream infections in Andalucía (Spain) during the last decade

ObjectivesDuring the last decade, some changes in the epidemiology of invasive infections have been reported; however, specific studies with patient-level data are scarce. The aim of this study was to describe and evaluate the epidemiologic changes in bloodstream infections (BSI) during the last decade in Andalucía, Spain.MethodsData from two prospective cohorts of BSI in adults with the same methodology performed 10 years apart in 11 hospitals (eight tertiary and three community) in Andalucía, Spain, were compared; the 2006–7 cohort study was performed between October 2006 and March 2007, and the 2016–17 cohort study was performed between October 2016 and March 2017. Population-based incidence rates were calculated and extrapolated for 1 year. Relative risk ratios were calculated between the 2 periods. Multivariate analyses were performed by logistic regression.ResultsOverall, 1262 episodes of BSI were included, 563 (44.6%) in 2006–7 and 699 (55.3%) in 2016–17. Multivariate models selected the following changes in patients' features in 2016–17, after controlling for type of acquisition: higher age (odds ratio (OR) = 1.02; 95% confidence interval [CI] 1.01–1.03), lower urinary catheter (OR = 0.37; 95% CI, 0.26–0.48) and lower Pitt score (OR = 0.76; 95% CI, 0.71–0.82). Adjusted estimations considering patients' features and exposure to procedures showed a reduction in coagulase-negative staphylococci (OR = 0.47; 95% CI, 0.32–0.69), and an increase in Proteus spp. (OR = 3.12; 95% CI, 1.18–8.23) and Candida spp. (OR = 3.01; 95% CI, 1.03–8.86).ConclusionsWe found relevant epidemiologic changes in BSI in our area, including rates, frequency of acquisition types, changes in patient's profiles and aetiologic agents.     

Aetiology of acute febrile illness in children in a high malaria transmission area in West Africa

ObjectivesAreas with declining malaria transmission in sub-Saharan Africa have recently witnessed important changes in the aetiology of childhood acute febrile illness (AFI). We describe the aetiology of AFI in a high malaria transmission area in rural Burkina Faso.MethodsIn a prospective hospital-based diagnostic study, children aged 3 months to 15 years with AFI were recruited and assessed using a systematic diagnostic protocol, including blood cultures, whole blood PCR on a selection of bacterial pathogens, malaria diagnostics and a multiplex PCR on nasopharyngeal swabs targeting 21 viral and 4 bacterial respiratory pathogens.ResultsA total of 589 children with AFI were enrolled from whom an infectious disease was considered in 575 cases. Acute respiratory tract infections, malaria and invasive bacterial infections (IBI) accounted for 179 (31.1%), 175 (30.4%) and 75 (13%) of AFI cases respectively; 16 (21.3%) of IBI cases also had malarial parasitaemia. A viral pathogen was demonstrated from the nasopharynx in 157 children (90.7%) with respiratory tract symptoms. Of all children with viral respiratory tract infections, 154 (92.4% received antibiotics, whereas no antibiotic was provided in 13 (17%) of IBI cases.ConclusionsViral respiratory infections are a common cause of childhood AFI in high malaria transmission areas, next to malaria and IBI. These findings highlight the importance of interventions to improve targeted treatment with antimicrobials. Most patients with viral infections received antibiotics unnecessarily, while a considerable number with IBI did not receive antibiotics.     

How do I manage a patient with enterococcal bacteraemia?

BackgroundEnterococcal bacteraemia (EB) is common, particularly in the nosocomial setting, and its management poses a challenge for clinicians and microbiologists.ObjectivesThe aim was to summarize the more relevant features of EB and to provide a practical state-of-the-art on the topics that more directly affect its management.SourcesPubmed articles from inception to 31 May 2020.ContentThe following topics are covered: epidemiological, clinical and microbiological characteristics and factors associated with prognosis of EB; diagnosis and work-up, including the use of echocardiography to rule out endocarditis; antibiotic management with special focus on antimicrobial resistance and complicated EB; and the role of infectious disease consultation and the use of bundles in EB. In addition, three clinical vignettes are presented to illustrate the practical application of the guidance provided, and major gaps in the current evidence supporting EB management are discussed.ImplicationsEB is associated with large burdens of morbidity and mortality, particularly among fragile and immunosuppressed patients presenting complicated bacteraemia due to multidrug-resistant enterococci. Most cases of EB are caused by Enterococcus faecalis, followed by E. faecium. EB often presents as polymicrobial bacteraemia. Rapidly identifying patients at risk of EB is crucial for timely application of diagnostic techniques and empiric therapy. Early alert systems and rapid diagnostic techniques, such as matrix-assisted desorption ionization–time of flight mass spectrometry, especially if used together with infectious disease consultation within bundles, appear to improve management and prognosis of EB. Echocardiography is also key in the work-up of EB and should probably be more extensively used, although its exact indications in EB are still debated. Multidisciplinary approaches are warranted due to the complexity and severity of EB.     

Distribution of pathogens and antimicrobial resistance in bacteraemia according to hospitalization duration: a nationwide surveillance study in Switzerland

ObjectivesChanging microorganism distributions and decreasing antibiotic susceptibility with increasing length of hospital stay have been demonstrated for the colonization or infection of selected organ systems. We wanted to describe microorganism distribution or antibiotic resistance in bacteraemia according to duration of the hospitalization using a large national epidemiological/microbiological database (ANRESIS) in Switzerland.MethodsWe conducted a nationwide, observational study on bacteraemia using ANRESIS data from 1 January 2008 to 31 December 2017. We analysed data on bacteraemia from those Swiss hospitals that sent information on a regular basis during the entire study period. We described the pathogen distribution and specific trends of resistance during hospitalization for Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Serratia marcescens and Staphylococcus aureus.ResultsWe included 28 318 bacteraemia isolates from 90 Swiss hospitals. The most common aetiology was E. coli (33.4%, 9459), followed by S. aureus (16.7%, 4721), K. pneumoniae (7.1%, 2005), Enterococcus faecalis (5.2%, 1473), P. aeruginosa (4.3%, 1228), Streptococcus pneumoniae (4.3%, 1208) and Enterococcus faecium (3.9%, 1101). We observed 489 (1.73%) S. marcescens isolates. We observed an increasing trend for E. faecium (from 1.5% at day 0 to 13.7% at day 30; p < 0.001), K. pneumoniae (from 6.1% to 7.8%, p < 0.001) and P. aeruginosa (from 2.9% to 13.7%, p < 0.001) with increasing duration of hospitalization; and decreasing trends for E. coli (from 41.6% to 21.6%; p < 0.001) and S. aureus (p < 0.001). Ceftriaxone resistance among E. coli remained stable for the first 15 days of hospitalization and then increased. Ceftriaxone resistance among K. pneumoniae and S. marcescens and oxacillin resistance among S. aureus increased linearly during the hospitalization. Cefepime resistance among P. aeruginosa remained stable during the hospitalization.DiscussionWe showed that hospitalization duration is associated with a species- and antibiotic class-dependent pattern of antimicrobial resistance.     

Immunomodulatory therapy,risk factors and outcomes of hospital-acquired bloodstream infection in patients with severe COVID-19 pneumonia: a Spanish case–control matched multicentre study (BACTCOVID)

ObjectivesThe effect of the use of immunomodulatory drugs on the risk of developing hospital-acquired bloodstream infection (BSI) in patients with COVID-19 has not been specifically assessed. We aim to identify risk factors for, and outcomes of, BSI among hospitalized patients with severe COVID-19 pneumonia.MethodsWe performed a severity matched case–control study (1:1 ratio) nested in a large multicentre prospective cohort of hospitalized adults with COVID-19. Cases with BSI were identified from the cohort database. Controls were matched for age, sex and acute respiratory distress syndrome. A Cox proportional hazard ratio model was performed.ResultsOf 2005 patients, 100 (4.98%) presented 142 episodes of BSI, mainly caused by coagulase-negative staphylococci, Enterococcus faecalis and Pseudomonas aeruginosa. Polymicrobial infection accounted for 23 episodes. The median time from admission to the first episode of BSI was 15 days (IQR 9–20), and the most frequent source was catheter-related infection. The characteristics of patients with and without BSI were similar, including the use of tocilizumab, corticosteroids, and combinations. In the multivariate analysis, the use of these immunomodulatory drugs was not associated with an increased risk of BSI. A Cox proportional hazard ratio (HR) model showed that after adjusting for the time factor, BSI was associated with a higher in-hospital mortality risk (HR 2.59; 1.65–4.07; p < 0.001).DiscussionHospital-acquired BSI in patients with severe COVID-19 pneumonia was uncommon and the use of immunomodulatory drugs was not associated with its development. When adjusting for the time factor, BSI was associated with a higher mortality risk.