Does Staphylococcus aureus Bacteriuria Predict Clinical Outcomes in Patients With Bacteremia?: Analysis of 274 Patients With Staphylococcus aureus Blood Stream Infection

A Narrative Review on the Role of Staphylococcus aureus Bacteriuria in S. aureus Bacteremia

Staphylococcus aureus bacteriuria (SABU) can occur in patients with S. aureus bacteremia (SAB). However, little is known on the (molecular) pathomechanisms of the renal passage of S. aureus. This review discusses the epidemiology and pathogenesis of SABU in patients with SAB and identifies knowledge gaps. The literature search was restricted to the English language. The prevalence of SABU in patients with SAB is 7.8%-39% depending on the study design. The main risk factor for SABU is urinary tract catheterization. SABU in SAB patients is associated with increased mortality. Given present evidence, hematogenous seeding-as seen in animal models-and the development of micro-abscesses best describe the translocation of S. aureus from blood to urine. Virulence factors that might be involved are adhesion factors, sortase A, and coagulase, among others. Other potential routes of bacterial translocation (eg, transcytosis, paracytosis, translocation via "Trojan horses") were identified as knowledge gaps.

Estimating the burden of antimicrobial resistance: a systematic literature review

Background

Accurate estimates of the burden of antimicrobial resistance (AMR) are needed to establish the magnitude of this global threat in terms of both health and cost, and to paramaterise cost-effectiveness evaluations of interventions aiming to tackle the problem. This review aimed to establish the alternative methodologies used in estimating AMR burden in order to appraise the current evidence base.

Methods

MEDLINE, EMBASE, Scopus, EconLit, PubMed and grey literature were searched. English language studies evaluating the impact of AMR (from any microbe) on patient, payer/provider and economic burden published between January 2013 and December 2015 were included. Independent screening of title/abstracts followed by full texts was performed using pre-specified criteria. A study quality score (from zero to one) was derived using Newcastle-Ottawa and Philips checklists. Extracted study data were used to compare study method and resulting burden estimate, according to perspective. Monetary costs were converted into 2013 USD.

Results

Out of 5187 unique retrievals, 214 studies were included. One hundred eighty-seven studies estimated patient health, 75 studies estimated payer/provider and 11 studies estimated economic burden. 64% of included studies were single centre. The majority of studies estimating patient or provider/payer burden used regression techniques. 48% of studies estimating mortality burden found a significant impact from resistance, excess healthcare system costs ranged from non-significance to $1 billion per year, whilst economic burden ranged from $21,832 per case to over $3 trillion in GDP loss. Median quality scores (interquartile range) for patient, payer/provider and economic burden studies were 0.67 (0.56-0.67), 0.56 (0.46-0.67) and 0.53 (0.44-0.60) respectively.

Conclusions

This study highlights what methodological assumptions and biases can occur dependent on chosen outcome and perspective. Currently, there is considerable variability in burden estimates, which can lead in-turn to inaccurate intervention evaluations and poor policy/investment decisions. Future research should utilise the recommendations presented in this review.

Trial registration

This systematic review is registered with PROSPERO (PROSPERO CRD42016037510).

The clinical significance of concomitant bacteriuria in patients with Staphylococcus aureus bacteremia. A review and meta-analysis

BACKGROUND

Staphylococcus aureus bacteriuria (SABU) concomitant to S. aureus bacteremia (SAB) has been associated with deep-seated infections and worse prognosis. However, the relevant studies were small and inconsistent. Here, we aim to provide a review of the relevant literature, and a meta-analysis of these studies.

METHODS

We searched PubMed and Scopus for studies comparing patients with SAB and concomitant SABU to patients with SAB without SABU.

RESULTS

Nine relevant studies were identified, involving 1429 patients with SAB, of whom 18.5% (n = 265) had concomitant SABU. Pooling the results of those studies, SABU was significantly associated with endocarditis, bone/joint infection and septic embolism. SABU was also associated with persistent SAB, and higher mortality.

CONCLUSIONS

Although SABU may be a useful marker of complicated SAB, the current literature has several limitations. Larger prospective studies are required to clarify the value of SABU in clinical decision making.

Evaluation and management of Staphylococcus aureus bacteriuria: an updated review

BACKGROUND AND AIMS

There is little guidance regarding the evaluation and management of patients with Staphylococcus aureus bacteriuria (SABU). Here, we aimed to provide an up-to-date review of the literature.

METHODS

We searched PubMed, Scopus, and clinical trial registries for articles evaluating the epidemiology of SABU, risk factors of SABU, the association of SABU with urinary tract infection, bacteremia and invasive S. aureus infections, and the management of patients with SABU.

RESULTS

S. aureus is an uncommon isolate in urine cultures. It is more common among certain patients, e.g., patients with indwelling urinary tract devices or prior urinary tract instrumentation. SABU may represent asymptomatic bacteriuria, primary urinary tract infection, or hematogenous seeding of the urinary tract associated with other foci of infection. SABU may also serve as the focus for subsequent bacteremia and invasive infections. We did not find any clinical trials regarding the management of patients with SABU.

CONCLUSIONS

Based on our review, we suggest an algorithmic approach for the evaluation and management of patients with SABU. However, evidence from clinical trials is lacking and there are several gaps in the current literature. These are discussed in this review.