Prevalence and risk factors for bacteremia in patients with Staphylococcus aureus bacteriuria: A retrospective cohort study

Abstract

Objectives: Staphylococcus aureus bacteriuria (SABU) is rare but can be an indicator of S. aureus bacteremia (SAB). The objective of this study was to assess the proportion of SAB in patients with SABU and identify risk factors in a hospital-based population. Methods: We used electronic databases to identify eligible patients to be enrolled in a retrospective cohort study. Inclusion criteria were (i) SABU, (ii) !18 years of age, and (iii) !1 blood culture sampled AE3 months of SABU. Patients with missing values for demographic (e.g., age, sex) or clinical characteristics (e.g., comorbidities) and laboratory analyses were excluded. Results: In total, 245 patients attending the University Hospital Münster, Germany, between 1 January 2012 and 31 December 2019 met the inclusion/exclusion criteria. Of the 245 patients with SABU, 66 had a concomitant SAB (26.9%). Elevated C-reactive protein (CRP) levels were associated with SAB. Other parameters (e.g., leukocytes, comorbidities) were not associated with SAB in a multivariate analysis. Conclusion:The frequency of SAB in patients with SABU was high and warrants active screening for bloodstream infections in hospitalized patients, particularly if CRP levels are elevated.

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

“…Many microbiology laboratories consider bacteriuria only above a minimum CFU, although a low concentration of S. aureus in urine samples may also be clinically relevant [ 5 ]. We define SABU as “the detection of S. aureus in a urine sample in any concentration (CFU/mL), independent of co-detected pathogens” [ 6 ].…”

“…The pooled prevalence of concomitant SABU in all SAB cases from eligible studies is 13%. We conducted a retrospective study (2012–2019) at the University Hospital Münster, Germany, among hospitalized patients with SABU and observed that 26.9% had concurrent or subsequent SAB [ 6 ]. Rates in other studies ( Table 2 ) range from 6.9% to 17.2% [ 15–21 ].…”

“…These numbers should be taken with caution, as a general definition of SABU and universal methodology to screen for SAB are lacking. For instance, in 1 study, all patients with SABU had blood cultures sampled [ 6 ], whereas others tested patients only for bacteremia when signs and symptoms of systemic infection (fever, leukocytosis, elevated C-reactive protein levels) were present [ 10 ].…”

“…Only 1 of the 12 patients had other antimicrobial treatment (piperacillin/tazobactam) one day before blood and urine culture sampling. Cefazolin or flucloxacillin intravenously for the treatment of methicillin-susceptible S. aureus and vancomycin, linezolid, or daptomycin for the treatment of methicillin-resistant S. aureus were considered effective antimicrobial therapies [ 6 , 22 ].…”

Staphylococcus aureus bacteriuria: implications and management

“… 2 , 6 , 7 It is postulated that SAB may be a cause or consequence of SABU, with risk factors for concurrent SAB including male sex, inpatient status, indicators of systemic infection, urinary tract abnormalities, lack of symptoms of urinary tract infection (UTI) and diabetes. 2 , 3 , 8 , 9 However, there is a paucity of guidance on the investigation and management of SABU, 10 including optimum antibiotic treatment.…”