Importance of focus identification in the treatment of Staphylococcus aureus bacteraemia

Staphylococcus aureus bacteremia in alcoholics

BACKGROUND

Alcoholism associates with increased Staphylococcus aureus bacteremia incidence and mortality. The objective was to compare disease progression, treatment and prognosis of Staphylococcus aureus bacteremia in alcoholics versus non-alcoholics.

METHODS

The study design was a multicenter retrospective analysis of methicillin-sensitive Staphylococcus aureus bacteremia with 90-day follow-up. Patients were stratified as alcoholics or non-alcoholics based on electronic health record data. Altogether 617 Staphylococcus aureus bacteremia patients were included of which 83 (13%) were alcoholics.

RESULTS

Alcoholics, versus non-alcoholics, were younger, typically male and more commonly had community-acquired Staphylococcus aureus bacteremia. No differences in McCabe´s classification of underlying conditions was observed. Higher illness severity at blood culture sampling, including severe sepsis (25% vs. 7%) and intensive care unit admission (39% vs. 17%), was seen in alcoholics versus non-alcoholics. Clinical management, including infectious disease specialist (IDS) consultations and radiology, were provided equally. Alcoholics, versus non-alcoholics, had more pneumonia (49% vs. 35%) and fewer cases of endocarditis (7% vs. 16%). Mortality in alcoholics versus non-alcoholics was significantly higher at 14, 28 and 90 days (14% vs. 7%, 24% vs. 11% and 31% vs. 17%), respectively. Considering all prognostic parameters, male sex (OR 0.19, p = 0.021) and formal IDS consultation (OR 0.19, p = 0.029) were independent predictors of reduced mortality, whereas ultimately or rapidly fatal comorbidity in McCabe´s classification (OR 12.34, p < 0.001) was an independent predictor of mortality in alcoholics.

CONCLUSIONS

Alcoholism deteriorates Staphylococcus aureus bacteremia prognosis, and our results suggests that this is predominantly through illness severity at bacteremia onset. Three quarters of Staphylococcus aureus bacteremia patients we studied had identified deep infection foci, and of them alcoholics had significantly less endocarditis but nearly half of them had pneumonia.

Impact of the COVID-19 Pandemic on the Management of Staphylococcus aureus Bloodstream Infections in a Tertiary Care Hospital

Staphylococcus aureus bacteremia (SAB) is associated with a high mortality rate. The clinical outcome of SAB patients highly depends on early diagnosis, adequate antibiotic therapy and source control. In the context of the COVID-19 pandemic, the health care system faced additional organizational challenges and the question arose whether structured screening and triaging for COVID-19 and shifting resources influence the management of SAB. Patients (n = 115) with SAB were enrolled in a retrospective comparative study with historical controls (March 2019-February 2021). The quality of SAB therapy was assessed with a point score, which included correct choice of antibiotic, adequate dosage of antibiotic, sufficient duration of therapy, early start of therapy after receipt of findings, focus search and taking control blood cultures 3-4 days after starting adequate antibiotic therapy. The quality of treatment before and after the onset of the COVID-19 pandemic were compared. No significant differences in the total score points were found between the pre-COVID-19 and COVID-19 cohort. All quality indicators, except the correct duration of antibiotic therapy, showed no significant differences in both cohorts. Furthermore, there were no significant differences in the outcome between both cohorts. The treatment quality of SAB therapy was comparable before and during the COVID-19 pandemic.

Infectious diseases specialist consultation in Staphylococcus lugdunensis bacteremia

Background

Commensal coagulase negative Staphylococcus lugdunensis may cause severe bacteremia (SLB) and complications. Treatment of SLB is not fully established and we wanted to evaluate if infectious diseases specialist consultation (IDSC) would improve management and prognosis.

Methods

Multicenter retrospective study of SLB patients followed for 1 year. Patients were stratified according to bedside (formal), telephone (informal) or lack of IDSC within 7 days of SLB diagnosis.

Results

Altogether, 104 SLB patients were identified: 24% received formal bedside and 52% informal telephone IDSC whereas 24% were managed without any IDSC. No differences in demographics, underlying conditions or severity of illness were observed between the groups. Patients with bedside IDSC, compared to telephone IDSC or lack of IDSC, had transthoracic echocardiography more often performed (odds ratio [OR] 4.00; 95% confidence interval [CI] 1.31–12.2; p = 0.012) and (OR 16.0; 95% CI, 4.00–63.9; P<0.001). Bedside IDSC was associated with more deep infections diagnosed compared to telephone IDSC (OR, 7.44; 95% CI, 2.58–21.4; p<0.001) or lack of IDSC (OR, 9.56; 95% CI, 2.43–37.7; p = 0.001). The overall mortality was 7%, 10% and 17% at 28 days, 90 days and 1 year, respectively. Considering all prognostic parameters, patients with IDSC, compared to lack of IDSC, had lower 90 days and 1 year mortality (OR, 0.11; 95% CI, 0.02–0.51; p = 0.005) and (OR, 0.22; 95% CI, 0.07–0.67; p = 0.007).

Conclusion

IDSC may improve management and outcome of Staphylococcus lugdunensis bacteremia.

Formal Infectious Diseases Specialist Consultation Improves Long-term Outcome of Methicillin-Sensitive Staphylococcus aureus Bacteremia

Background

Formal infectious diseases specialist (IDS) consultation has been shown to improve short-term outcomes in Staphylococcus aureus bacteremia (SAB), but its effect on long-term outcomes lacks evaluation.

Methods

This retrospective study followed 367 methicillin-sensitive (MS) SAB patients for 10 years. The impact of formal IDS consultation on risk for new bacteremia and outcome during long-term follow-up was evaluated. Patients who died within 90 days were excluded to avoid interference from early deceased patients.

Results

Three hundred four (83%) patients had formal IDS consultation, whereas 63 (17%) received informal or no IDS consultation. Formal consultation, compared with informal or lack of consultation, was associated with a reduced risk of new bacteremia caused by any pathogen within 1 year (odds ratio [OR], 0.39; 95% confidence interval [CI], 0.18–0.84; P = .014; 8% vs 17%) and within 3 years (OR, 0.39; 95% CI, 0.19–0.80; P = .010; 9% vs 21%), whereas a trend toward lower risk was observed within 10 years (OR, 0.56; 95% CI, 0.29–1.08; P = .079; 16% vs 25%). Formal consultation, compared with informal or lack of consultation, improved outcomes at 1 year (OR, 0.16; 95% CI, 0.06–0.44; P < .001; 3% vs 14%), at 3 years (OR, 0.19; 95% CI, 0.09–0.42; P < .001; 5% vs 22%), and at 10 years (OR, 0.43; 95% CI, 0.24–0.74; P = .002; 27% vs 46%). Considering all prognostic parameters, formal consultation improved outcomes (HR, 0.42; 95% CI, 0.27–0.65; P < .001) and lowered risk for any new bacteremia (OR, 0.45; 95% CI, 0.23–0.88; P = .02) during 10 years of follow-up.

Conclusions

MS-SAB management by formal IDS consultation, compared with informal or lack of IDS consultation, reduces risk for new bacteremia episodes and improves long-term prognosis up to 10 years.

Clinical value of FDG-PET/CT in bacteremia of unknown origin with catalase-negative gram-positive cocci or Staphylococcus aureus

INTRODUCTION

Bacteremia is associated with high mortality, especially when the site of infection is unknown. While conventional imaging usually focus on specific body parts, FDG-PET/CT visualizes hypermetabolic foci throughout the body.

PURPOSE

To investigate the ability of FDG/PET-CT to detect the site of infection and its clinical impact in bacteremia of unknown origin with catalase-negative Gram-positive cocci (excluding pneumococci and enterococci) or Staphylococcus aureus (BUOCSA).

METHODS

We retrospectively identified 157 patients with 165 episodes of BUOCSA, who subsequently underwent FDG-PET/CT. Data were collected from medical records. Decision regarding important sites of infection in patients with bacteremia was based on the entire patient course and served as reference diagnosis for comparison with FDG-PET/CT findings. FDG-PET/CT was considered to have high clinical impact if it correctly revealed site(s) of infection in areas not assessed by other imaging modalities or if other imaging modalities were negative/equivocal in these areas, or if it established a new clinically relevant diagnosis, and/or led to change in antimicrobial treatment.

RESULTS

FDG-PET/CT detected sites of infection in 56.4% of cases and had high clinical impact in 47.3%. It was the first imaging modality to identify sites of infection in 41.1% bacteremia cases, led to change of antimicrobial therapy in 14.7%, and established a new diagnosis unrelated to bacteremia in 9.8%. Detection rate and clinical impact were not significantly influenced by duration of antimicrobial treatment preceding FDG-PET/CT, days from suspicion of bacteremia to FDG-PET/CT-scan, type of bacteremia, or cancer.

CONCLUSION

FDG-PET/CT appears clinically useful in BUOCSA. Prospective studies are warranted for confirmation.

Methicillin-sensitive Staphylococcus aureus bacteremia in aged patients: the importance of formal infectious specialist consultation

Background

Infectious specialist consultations (ISC) provide ever more evidence for improved outcome in Staphylococcus aureus bacteremia (SAB). Most ISC are formal (bedside). However, the impact of ISC on clinical management and prognosis lacks evaluation in aged patients with SAB.

Methods

Multicenter retrospective analysis of methicillin-sensitive (MS) SAB. Patients were stratified according to age ≥ 60 years (sub-analyses for ≥ 75 years and females) and formal (bedside) ISC given within 7 days of SAB diagnosis. The impact on management and outcome of formal ISC was explored. Statistics were performed with univariate analysis, Cox proportional hazards regression model analysis, including propensity-score adjustment, and graphic Kaplan–Meier interpretation.

Results

Altogether 617 patients were identified and 520 (84%) had formal ISC. Presence of formal ISC resulted in equivalent clinical management regardless of age over or under 60 years: localization and eradication of infection foci (80 vs. 82% and 34 vs. 36%) and use of anti-staphylococcal antibiotics (65 vs. 61%). Patients aged ≥ 60 years managed without formal ISC, compared to those with formal ISC, had less infection foci diagnosed (53 vs. 80%, p < 0.001). Lack of formal ISC in patients aged ≥ 60 years resulted in no infection eradication and absence of first-line anti-staphylococcal antibiotics. Formal ISC, compared to absence of formal ISC, lowered mortality at 90 days in patients aged ≥ 60 years (24 vs. 47%, p = 0.004). In Cox proportional regression, before and after propensity-score adjustment, formal ISC was a strong positive prognostic parameter in patients aged ≥ 60 years (HR 0.45; p = 0.004 and HR 0.44; p = 0.021), in patients aged ≥ 75 years (HR 0.18; p = 0.001 and HR 0.11; p = 0.003) and in female patients aged ≥ 75 years (HR 0.13; p = 0.005).

Conclusion

Formal ISC ensures proper active clinical management irrespective of age and improve prognosis in aged patients with MS-SAB.

Staphylococcus aureus bacteremia: targeting the source

Bacteremia due to Staphylococcus aureus is one of the major causes of morbidity and mortality in India, but studies targeting the source of Staphylococcus aureus bacteremia are lacking. S. aureus has a vivid armamentarium consisting of toxins, adhesins, and other virulence factors by virtue of which it can cause varied types of infections, sometimes of a serious nature. This review highlights the possible causes of S. aureus bacteremia, and discusses the necessity of tracing its source and eliminating it with proper antibiotic therapy to avoid recurrences or relapses.

Clinical impact of 18F-FDG-PET/CT in the extra cardiac work-up of patients with infective endocarditis

OBJECTIVE

The purpose of this study was to assess the clinical importance of 18F-FDG-PET/CT used in the extra cardiac work-up of patients with infective endocarditis (IE).

BACKGROUND

IE is a serious condition with a significant mortality. Besides the degree of valvular involvement, the prognosis relies crucially on the presence of systemic infectious embolism.

METHODS

Seventy-two patients (71% males and mean age 63 ± 17 years) with IE were evaluated with 18F-FDG-PET/CT in addition to standard work-up including patient history, physical examination, conventional imaging modalities, and weekly interdisciplinary conferences. When previous unknown lesions detected by 18F-FDG-PET/CT were confirmed by succeeding examinations, they were considered true positive new findings and were further assessed for their clinical importance. Number needed to investigate was calculated as the number of patients who needed to undergo 18F-FDG-PET/CT to find at least one clinical important true positive new finding, not identified by standard work-up prior to 18F-FDG-PET/CT.

RESULTS

18F-FDG-PET/CT detected 114 lesions and 64 were true positive, of which 25 were new findings and detected in 17 patients. In 11 patients, the lesions were considered to have a clinical importance; osteomyelitis (n = 7), iliopsoas abscess (n = 1), gastrointestinal lesions (n = 2), and vascular prosthetic graft (n = 1). Number needed to investigate was 7 (11 of 72 patients).

CONCLUSIONS

18F-FDG-PET/CT detected lesions of clinical importance in one of seven IE patients and may be a substantial imaging technique for tracing peripheral infectious embolism due to IE. Thus, 18F-FDG-PET/CT may help to guide adequate therapy and thereby improve the prognosis of patients with IE.

Metastatic infectious disease and clinical outcome in Staphylococcus aureus and Streptococcus species bacteremia

Early detection of metastatic infection in patients with Gram-positive bacteremia is important as morbidity and mortality are higher in the presence of these foci, probably due to incomplete eradication of clinically silent foci during initial treatment. We performed a prospective study in 115 patients with Staphylococcus aureus or Streptococcus species bacteremia with at least 1 risk factor for the development of metastatic foci, such as community acquisition, treatment delay, persistently positive blood cultures for >48 hours, and persistent fever >72 hours after initiation of treatment. An intensive search for metastatic infectious foci was performed including ¹⁸F-fluorodeoxyglucose-positron emission tomography in combination with low-dose computed tomography scanning for optimizing anatomical correlation (FDG-PET/CT) and echocardiography in the first 2 weeks of admission. Metastatic infectious foci were detected in 84 of 115 (73%) patients. Endocarditis (22 cases), endovascular infections (19 cases), pulmonary abscesses (16 cases), and spondylodiscitis (11 cases) were diagnosed most frequently. The incidence of metastatic infection was similar in patients with Streptococcus species and patients with S. aureus bacteremia. Signs and symptoms guiding the attending physician in the diagnostic workup were present in only a minority of cases (41%). An unknown portal of entry, treatment delay >48 hours, and the presence of foreign body material were significant risk factors for developing metastatic foci. Mean C-reactive protein levels on admission were significantly higher in patients with metastatic infectious foci (74 vs. 160 mg/L). FDG-PET/CT was the first technique to localize metastatic infectious foci in 35 of 115 (30%) patients. As only a minority of foci were accompanied by guiding signs or symptoms, the number of foci revealed by symptom-guided CT, ultrasound, and magnetic resonance imaging remained low. Mortality tended to be lower in patients without complicated infection compared to those with metastatic foci (16% vs. 25%, respectively). Five of 31 patients (16%) without proven metastatic foci died. In retrospect, 3 of these 5 patients likely had metastatic foci that could not be diagnosed while alive. In patients with Gram-positive bacteremia and a high risk of developing complicated infection, a structured protocol including echocardiography and FDG-PET/CT aimed at detecting metastatic infectious foci can contribute to improved outcome.

Cost-effectiveness of routine (18)F-FDG PET/CT in high-risk patients with gram-positive bacteremia

Gram-positive bacteremia has a high morbidity and mortality rate of approximately 30%. Delayed diagnosis of clinically silent metastatic infectious foci is an important indicator for a complicated outcome. (18)F-FDG PET/CT allows detection of focal infection, resulting in lower relapse rates and mortality. Here, we present a cost-effectiveness analysis associated with introduction of (18)F-FDG PET/CT for patients with gram-positive bacteremia.

METHODS

A cost-effectiveness analysis in a prospective (18)F-FDG PET/CT group (n = 115) and matched control group (n = 230) was performed alongside a clinical study, the results of which were previously published. Mortality at 6 mo was considered the final effect outcome and was used in the denominator of the incremental cost-effectiveness ratio.

RESULTS

Mortality in the (18)F-FDG PET/CT group was 19%, compared with 32% in the control group (P < 0.01). Incremental costs of (18)F-FDG PET/CT were $9,454 (95% confidence interval [CI], $3,963-$14,947), mainly because of admission (mean, $6,631; 95% CI, $1,449-$11,814). Additional costs were related to echocardiography (P < 0.01), not to (18)F-FDG PET/CT (P = 0.8). The mean incremental costs of the (18)F-FDG PET/CT strategy estimated by stratification for endocarditis were $5,277 per patient (95% CI, $429-$10,123; P = 0.03). The point estimate of the incremental cost-effectiveness ratio is $72,487 per prevented death (95% CI, $11,388-$323,379).

CONCLUSION

Introduction of a diagnostic regimen including routine (18)F-FDG PET/CT decreases morbidity and mortality. The cost increase is due to in-hospital treatment of metastatic infectious foci. Costs per prevented death, $72,487, are within the range that is considered to be efficient by Dutch guidelines. Patients with high-risk gram-positive bacteremia therefore should have easy access to (18)F-FDG PET/CT to enable early detection of metastatic infectious disease.

Predisposing factors, disease progression and outcome in 430 prospectively followed patients of healthcare- and community-associated Staphylococcus aureus bacteraemia

Staphylococcus aureus bacteraemia (SAB) episodes identified in a prospective multicentre study during 1999-2002 (not including MRSA) were followed up by an infectious disease specialist. The aim of this study was to compare predisposing factors, disease progression and outcome of healthcare (HA)- and community (CA)-associated SAB. Of 430 SAB episodes, 232 (54%) were HA. The HA-SAB patients were significantly older and more chronically ill compared to CA-SAB. Deep infection foci prevalence within three days of onset of SAB for HA versus CA were deep-seated abscesses (26% vs 37%, P < 0.05), pneumonia [25% vs 31%, non-significant (NS)], osteomyelitis (24% vs 36%, P<0.01), permanent foreign body (24% vs 9%, P<0.001), endocarditis (11% vs 15%, NS), septic arthritis (9% vs 13%, NS) and no infection focus (3% vs 6%, NS). The case fatality rates for HA-SAB versus CA-SAB at 28 days were 14% vs 11% (NS). Independent risk factors according to multivariate analysis for a fatal outcome were age, chronic alcoholism, immunosuppressive treatment, ultimately or rapidly fatal underlying diseases, severe sepsis on the onset of SAB, S. aureus pneumonia and endocarditis. As a result of a prospective study design, meticulous infection foci search and infectious disease specialist follow-up of each SAB episode, the case fatality remained low and 97% of the HA-SAB episodes presented infection foci within three days of onset of bacteraemia.

Frequency and risk factors for deep focus of infection in children with Staphylococcus aureus bacteremia

BACKGROUND

Staphylococcus aureus bacteremia (SAB) in children may be associated with development of deep-seated foci of infection, often prompting extensive diagnostic testing. The objective of this study was to establish the frequency and risk factors for deep foci of infection from SAB in pediatric patients.

METHODS

Medical charts of all children admitted with SAB to a tertiary-care center from January 1992 to June 2006 were reviewed. Study outcome was the presence of a deep focus of infection as documented by positive echocardiogram, bone imaging or abdominal imaging.

RESULTS

We studied 298 children, of whom 190 (64%) had echocardiograms, 116 (39%) had abdominal imaging, and 103 (35%) had bone imaging. Forty-seven subjects (16%) had symptoms of a deep focus of infection on discovery of SAB, which then was confirmed by 1 of the 3 tests. Eleven (3.7%) additional subjects had a clinically unsuspected deep focus identified before discharge. All children with an unsuspected deep focus of infection had either an underlying medical condition that potentially obscured the diagnosis or a central venous catheter. More than 1 day of positive blood cultures was associated with an unsuspected deep-seated infection (P < 0.01). Endocarditis was uncommon (2.7%), and occurred only in children with known congenital heart disease or with a central catheter.

CONCLUSIONS

Deep-seated infections from SAB in children are most often clinically apparent at discovery of bacteremia. Unsuspected deep-seated infection is uncommon and confined to specific hosts. Routine diagnostic imaging is not indicated in all children with SAB.

Clinical epidemiology and outcomes of peripheral venous catheter-related bloodstream infections at a university-affiliated hospital

Despite enormous clinical experience of using peripheral vascular catheters, there is still controversy over the incidence and clinical relevance of bloodstream infections caused by these devices and the measures for preventing them. We performed a prospective study to determine the clinical epidemiology and outcomes of nosocomial bloodstream infections caused by short- and mid-line peripheral venous catheters among a group of non-intensive care unit patients. Cases of peripheral venous catheter-related bloodstream infections (PVC-BSIs) were compared to cases of central venous catheter-related bloodstream infections (CVC-BSIs). From October 2001 to March 2003, 150 cases of vascular catheter-related bloodstream infections were identified among 147 patients. Seventy-seven episodes (0.19 cases/1000 patient-days) were PVC-BSIs and 73 episodes (0.18 cases/1000 patient-days) were CVC-BSIs. Compared with CVC-BSIs, patients with PVC-BSIs more often had the catheter inserted in the emergency department (0 vs 42%), had a shorter duration from catheter insertion to bacteraemia (mean: 15.4 vs 4.9 days) and had Staphylococcus aureus (33 vs 53%) more frequently as the causative pathogen. Among patients with PVC-BSIs, catheters inserted in the emergency department had a significantly shorter duration in situ compared with those inserted on hospital wards (mean: 3.7 vs 5.7 days). Patients with PVC-BSIs caused by S. aureus had a higher rate of complicated bacteraemia (7%) and higher overall mortality (27%) than patients with PVC-BSIs caused by other pathogens (0 and 11%, respectively). Bloodstream infections remain underestimated and potentially serious complications of peripheral vascular catheterisation. Targeted interventions should be introduced to minimise this complication.

A 5-year PICU experience of disseminated staphylococcal disease, part 2: management, critical care needs and outcome

Staphylococcus aureus causes an impressive spectrum of disease in tropics and subtropics. Scanty data are available regarding disseminated staphylococcal disease (DSD) in children, especially on their critical care needs. It is important to recognize and prioritize patients who may benefit most from Pediatric Critical Care. The objective of this article is to review the, critical care needs, management and outcome of patients with DSD and to identify clinical indicators for need of critical care. The study setting is a Pediatric Intensive Care Unit of an urban tertiary care teaching hospital in a developing economy. Fifty-three patients (age, 1 month to 12 years) with DSD, admitted to PICU during June 1994 to June 1999, form the subjects for the study. DSD was defined as involvement of at least two distant organs with presence of Gram-positive cocci in clusters and/or growth of S. aureus from at least one normally sterile body fluid. Data regarding demographic and clinical picture, microbiological profile, indication for PICU admission, monitoring needs, medical and surgical management and outcome was retrieved from the case records. Critical care problems included septic shock (28/53), pericardial effusion (21/53, cardiac tamponade in six), raised intracranial pressure (5 patients) and refractory status epilepticus (1 patient). The majority developed septic shock after first few doses of parenteral antimicrobials. They required an impressive amount of fluid [100 (56) ml/kg] during initial 6 h of resuscitation, and 90% had myocardial dysfunction requiring inotropic support. Tracheal intubation was needed in 18 (34%) and ventilatory support in 17 (32%) patients. About 60% patients had metabolic abnormalities. Soft tissue disease was associated with high risk of septic shock (RR, 1.77; P < 0.05). Presence of both septic shock and need for ventilation was associated with high mortality (RR, 20.5; P < 0.001). Patients with suspected DSD need intensive cardio-respiratory monitoring during initial 48-72 h of therapy; and those who develops shock, respiratory failure, pericardial effusion and necrotizing soft tissue disease should be prioritized for PICU admission.

Severe Sepsis Attributable to Community-Associated Methicillin-Resistant Staphylococcus aureus: An Emerging Fatal Problem

We observed a number of cases of sepsis from bacteremia in children from community-associated methicillin-resistant Staphylococcus aureus (MRSA), which led us to study its patterns of infection and outcome. A retrospective review identifying children admitted to our institution with blood culture-proven community-associated MRSA sepsis over a 2-year period was performed. The inclusion criteria were younger than 19 years old, two or more blood cultures for MRSA within 48 hours of admission, evidence of systemic inflammatory response syndrome, and no prior hospital admissions within 6 months. Eight patients were included; seven required mechanical ventilation. Vasopressors were required in seven patients. Four patients required extra-corporeal membrane oxygenation. Four patients had culture-proven septic arthritis or thrombophlebitis and three of these patients developed bilateral necrotizing pneumonia. Bilateral necrotizing pneumonia was identified in the other four patients, but the primary source of infection was never identified. The overall intact neurologic survival was 50 per cent. Children with severe community-associated MRSA sepsis can rapidly progress to cardiorespiratory failure. Mortality appears to be high, and children may benefit from a search of their soft tissues and joints to identify the source of infection to prevent embolic dissemination.

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.

Haematogenous Staphylococcus aureus meningitis. A 10-year nationwide study of 96 consecutive cases

Background

Haematogenous Staphylococcus aureus meningitis is rare but associated with high mortality. Knowledge about the disease is still limited. The objective of this study was to evaluate demographic and clinical prognostic features of bacteraemic S. aureus meningitis.

Methods

Nationwide surveillance in Denmark from 1991 to 2000 with clinical and bacteriological data. Risks of death were estimated by Cox proportional hazards regression analysis.

Results

Among 12480 cases of S. aureus bacteraemia/sepsis, we identified 96 cases of non-surgical bacteraemic S. aureus meningitis (0.8%). Incidence rates were 0.24 (95% confidence interval [CI], 0.18 to 0.30)/100 000 population between 1991–1995 and 0.13 (CI, 0.08 to 0.17)/100 000 population between 1996–2000. Mortality was 56%. After adjustment, only co morbidity (hazard ratio [HR], 3.45; CI, 1.15 to 10.30) and critical illness (Pitt score ≥ 4) (HR, 2.14; CI, 1.09 to 4.19) remained independent predictors of mortality.

Conclusion

The incidence, but not mortality of bacteraemic S. aureus meningitis decreased during the study period. Co morbidity and critical illness were independent predictors of a poor outcome.

Levofloxacin does not decrease mortality in Staphylococcus aureus bacteraemia when added to the standard treatment: a prospective and randomized clinical trial of 381 patients

OBJECTIVES

To study whether levofloxacin, added to standard treatment, could reduce the high mortality and complication rates in Staphylococcus aureus bacteraemia.

DESIGN

A prospective randomized multicentre trial from January 2000 to August 2002.

SETTING

Thirteen tertiary care or university hospitals in Finland.

SUBJECTS

Three hundred and eighty-one adult patients with S. aureus bacteraemia. Patients with meningitis, and those with fluoroquinolone- or methicillin-resistant S. aureus were excluded.

INTERVENTIONS

Standard treatment (mostly semisynthetic penicillin) (n = 190) or that combined with levofloxacin (n = 191). Supplementary rifampicin was recommended if deep infection was suspected.

MAIN OUTCOME MEASURES

Primary end-points were mortality at 28 days and at 3 months. Clinical and laboratory parameters were analysed as secondary end-points.

RESULTS

Adding levofloxacin to the standard treatment offered no survival benefit. Case fatality rates were 14% in both groups at 28 days, and 21% in the standard treatment and 18% in the levofloxacin group at 3 months. Levofloxacin combination did not differ from the standard treatment in the number of complications, time to defervescence, decrease in serum C-reactive protein concentration or length of antibiotic treatment. Deep infection was found in 84% of patients within 1 week following randomization with no difference between the treatment groups. At 3 months, the case fatality rate for patients with deep infection was 17% amongst those who received rifampicin versus 38% for those without rifampicin (P < 0.001, odds ratio = 3.06, 95% confidence intervals = 1.69-5.54).

CONCLUSIONS

Levofloxacin combined with standard treatment in S. aureus bacteraemia did not decrease mortality or the incidence of deep infections, nor did it speed up recovery. Interestingly, deep infections in S. aureus bacteraemia appeared to be more common than previously reported.

Nosocomial infections in the intensive care units

Background/Aim. The risk for nosocomial infections (NIs) is 5-10 times higher in patients hospitalized in the Intensive Care Units (ICUs) than in patients staying in other wards. The higher incidence rates of NIs in the ICUs may be explained by the fact that the patients in the ICUs have more severe underlying disease, and are exposed to the invasive diagnostic and therapeutical procedures. The unreasonable use of antibiotics leads to the selection of multiresistant agents, which have been increasingly recorded as the NIs causative agents. The aim of this study was to investigate the characteristics of NIs in the ICUs in the period January-June 2005. Methods. The study of incidence was performed in accordance with the methodology of the Centers for Diseases and Prevention. Any infections in the patients hospitalized in the ICUs in the period from January to June 2005 were registered. The results both from medical documentation and from the direct contacts with the medical personnel were analyzed. The samples were tested using standard methods in the microbiological laboratory. Results. The incidence rates of NIs patients ranged from 1.5 to 40.8, and the incidence rates of infections were 1.5 to 65.6 per 1 000 patient?s days. Out of the total number of NIs, urinary infections accounted for 44.6%, blood infections for 37.6%, and surgical site infections for 16.9%. Conclusion. The most frequent cause of nosocomial urinary infections was Klebsiella, of nosocomial sepsis - coagulase ? negative staphylococci, and of surgical site infections - Staphylococcus aureus.

Review of Staphylococcus aureus infections requiring admission to a paediatric intensive care unit

AIMS

To review clinical features and outcome of children with severe Staphylococcus aureus sepsis (SAS) presenting to a paediatric intensive care unit (PICU) with particular focus on ethnicity, clinical presentation, cardiac involvement, and outcome.

METHODS

Retrospective chart review of patients coded for SAS over 10 years (October 1993 to April 2004).

RESULTS

There were 58 patients identified with SAS over the 10 year study period; 55 were community acquired. This accounted for 4% of hospital admissions for SAS over this time; children with staphylococcal illness comprised 1% of all admissions to the PICU. Maori and Pacific children with SAS were overly represented in the PICU (81%) from a paediatric population where they contribute 21.6%. Musculoskeletal symptoms (79%) dominated presentation rather than isolated pneumonia (10%). An aggressive search for foci and surgical drainage of infective foci was required in 50% of children. Most children had multifocal disease (67%) and normal cardiac valves (95%); the few children (12%) presenting with methicillin resistant S aureus (MRSA) had community acquired infection. The median length of stay in the PICU was 3 (mean 5.8, SD 7.6, range 1-44) days. The median length of stay in hospital was 15 (mean 21, SD 22.7, range 2-149) days. Mortality due to SAS was 8.6% (95% CI 1.4-15.8%) compared with the overall mortality for the PICU of 6% (95% CI 5.3-6.7%). Ten children had significant morbidity after discharge.

CONCLUSIONS

Community acquired SAS affects healthy children, is multifocal, and has high morbidity and mortality, in keeping with the high severity of illness scores on admission. It is imperative to look for sites of dissemination and to drain and debride foci. Routine echocardiography had low yield in the absence of pre-existing cardiac lesions, persisting fever, or persisting bacteraemia.

Outcome of Staphylococcus aureus bacteremia in patients with eradicable foci versus noneradicable foci

To determine the outcome of Staphylococcus aureus bacteremia (SAB) on mortality, including the impact of methicillin resistance and an initial delay (< or =48 h) of appropriate antibiotics, a retrospective cohort study including 238 patients with SAB was performed. By logistic regression, noneradicable or noneradicated foci, underlying cirrhosis, and cancer were found to be independent predictors of mortality. In patients with eradicable foci, there were no significant differences in the associated mortality rate between methicillin-resistant SAB (11%) and methicillin-susceptible SAB (13%), and between inappropriate (13%) and appropriate (10%) empirical therapy, respectively (P=.79 and P=.78, respectively). By logistic regression, it was found that, in the subgroup of patients with noneradicable foci, underlying cirrhosis (odds ratio [OR], 3.1) and methicillin-resistant SAB (OR, 2.4) were independently associated with mortality.