Predictive Value of C-Reactive Protein (CRP) in Identifying Fatal Outcome and Deep Infections in Staphylococcus aureus Bacteremia

Retrospective study to investigate appropriate duration of antibiotic treatment for uncomplicated Staphylococcus aureus bacteremia in patients with immunodeficiency

BACKGROUND

Since the appropriate antibiotic duration for uncomplicated Staphylococcus aureus (S. aureus) bacteremia (u-SAB) in an immunocompromised state is still unclear, physicians are likely to extend antibiotic therapy from 2 weeks to 4-6 weeks. To examine the appropriate duration of antibiotic therapy for u-SAB, we performed this study.

PATIENTS AND METHODS

We reviewed all patients with u-SAB at our institute seen between January 2020 and August 2023. A total of 51 patients were enrolled, and they were divided into the following two groups by antibiotic duration: longer duration group ≥28 days after blood culture negativity, and shorter duration group. Then, the patients were matched by a propensity score using the covariates of age, sex, qSOFA, and CCI. The primary outcome was to identify the prognosis by duration of antibiotic treatment.

RESULTS

After propensity score matching, all-cause 30-day mortality was 0 % in both groups. Hence, there was no significant difference in all-cause 90 days mortality (19.0% vs 9.5%, p = 0.33) or recurrence (9.5%% vs 0%, p = 0.22). Before propensity-score matching, we found that a serum level of CRP 2.0 mg/dL and greater after intravenous antibiotic treatment was one of the poor prognostic factors. The cut-off value of serum CRP level was 2.0 mg/dL with a sensitivity of 82.1% and a specificity of 75.0%.

CONCLUSION

We suggested that 4-6 weeks of antibiotic treatment for immunodeficient u-SAB patients was unnecessary. Moreover, the serum level of CRP after completion of IV antibiotic treatment could be a prognostic marker for u-SAB.

Phenome-wide association study identifies new clinical phenotypes associated with Staphylococcus aureus infections

BACKGROUND

Phenome-Wide Association study (PheWAS) is a powerful tool designed to systematically screen clinical observations derived from medical records (phenotypes) for association with a variable of interest. Despite their usefulness, no systematic screening of phenotypes associated with Staphylococcus aureus infections (SAIs) has been done leaving potential novel risk factors or complications undiscovered.

METHOD AND COHORTS

We tailored the PheWAS approach into a two-stage screening procedure to identify novel phenotypes correlating with SAIs. The first stage screened for co-occurrence of SAIs with other phenotypes within medical records. In the second stage, significant findings were examined for the correlations between their age of onset with that of SAIs. The PheWAS was implemented using the medical records of 754,401 patients from the Marshfield Clinic Health System. Any novel associations discovered were subsequently validated using datasets from TriNetX and All of Us, encompassing 109,884,571 and 118,538 patients respectively.

RESULTS

Forty-one phenotypes met the significance criteria of a p-value < 3.64e-5 and odds ratios of > 5. Out of these, we classified 23 associations either as risk factors or as complications of SAIs. Three novel associations were discovered and classified either as a risk (long-term use of aspirin) or complications (iron deficiency anemia and anemia of chronic disease). All novel associations were replicated in the TriNetX cohort. In the All of Us cohort, anemia of chronic disease was replicated according to our significance criteria.

CONCLUSIONS

The PheWAS of SAIs expands our understanding of SAIs interacting phenotypes. Additionally, the novel two-stage PheWAS approach developed in this study can be applied to examine other disease-disease interactions of interest. Due to the possibility of bias inherent in observational data, the findings of this study require further investigation.

Risk Factors for Persistent Staphylococcus aureus Bacteremia in Children

BACKGROUND

Staphylococcus aureus is a leading cause of pediatric bacteremia. Persistent S. aureus bacteremia (SAB) is associated with increased morbidity and mortality in adults and children. Risk factors for S. aureus bacteremia have been well established, but there is a limited understanding of the factors that contribute to the development of persistent SAB in children.

METHODS

This is a single-center retrospective secondary analysis of a prospective observational study of pediatric patients hospitalized with S. aureus infection over a 3.5-year period at a large, quaternary, children's hospital.

RESULTS

Two hundred fifty-nine children with confirmed S. aureus infection were enrolled in the study. Sixty-five of these were found to have bacteremia, with 28 (43%) developing persistent bacteremia. Patients with persistent SAB were culture-positive for a median of 3.5 days compared with 1 day for those without (P ≤ 0.001). Children with persistent SAB were more likely to have an identified osteoarticular source of infection (93%, n = 26 vs. 62%, n = 23; P = 0.008) and had a shorter median duration to culture positivity than those without persistent SAB (16 hours vs. 20 hours; P ≤ 0.001). In addition, children with persistent SAB had higher median values of presenting erythrocyte sedimentation rate, peak erythrocyte sedimentation rate, presenting C-reactive protein and peak C-reactive protein. Not surprisingly, hospital length of stay was longer in children with persistent SAB compared with those without.

CONCLUSIONS

These findings suggest that a shorter time to culture positivity, osteoarticular infection, and higher presenting and peak values for select inflammatory markers are potential risk factors for persistent SAB in children.

Diagnostic value of Procalcitonin, C-reactive protein-to-lymphocyte ratio (CLR), C-reactive protein and neutrophil-to-lymphocyte ratio (NLR) for predicting patients with Bacteraemia in the intensive care unit

BACKGROUND

To explore the diagnostic value of procalcitonin (PCT), C-reactive protein-to-lymphocyte ratio (CLR), C-reactive protein (CRP) and neutrophil-to-lymphocyte ratio (NLR) for predicting patients with bacteremia in the intensive care unit (ICU).

METHODS

This case-control study included 359 patients with suspected bacteremia were divided into a bacteremia group (n = 152) and a control group (n = 207) from September 2018 to April 2023. Patient data were collected using a laboratory information system (LIS). ROC curves for PCT, CLR, CRP, and NLR in predicting patients with bacteremia.

RESULTS

For PCT, CLR, CRP and NLR to predict patients with bacteremia in the ICU, the AUCs were 0.991(95%CI: 0.974-0.998), 0.960(95%CI: 0.935-0.978), 0.955(95%CI: 0.928-0.974), and 0.898(95%CI:0.862-0.927), respectively; the optimal thresholds were 0.248 ng/mL, 47.52 mg/109, 48.32 mg/L, and 6.51, respectively; the sensitivities were 95.4(95%CI: 90.7-98.1), 88.2(95%CI: 81.9-92.8), 87.5(95%CI: 81.2-92.3), and 86.8(95%CI:80.4-91.8), respectively; and the specificities were 95.7(95%CI: 91.9-98.0), 90.8(95%CI: 86.0-94.4), 90.3(95%CI: 85.5-94.0), and 85.0(95%CI:79.4-89.6), respectively. The sensitivities of PCT, CLR, CRP and NLR for predicting bacteremia due to E. coli infection are as high as over 90%, the specificity of PCT is 100, and the sensitivity of NLR is 100. The sensitivity of CRP for predicting bacteremia due to non-Enterobacer infection is 100.

CONCLUSIONS

Compared with those in the control group, PCT, CLR, CRP and NLR were significantly greater in the bacteremia group. The PCT, CLR, CRP, and NLR can all predict the occurrence of bacteremia. The PCT had the highest sensitivity and specificity in predicting bacteremia in ICU patients.

Female Sex and Mortality in Patients with Staphylococcus aureus Bacteremia: A Systematic Review and Meta-analysis

Importance

Staphylococcus aureus is the leading cause of death due to bacterial bloodstream infection. Female sex has been identified as a risk factor for mortality in S aureus bacteremia (SAB) in some studies, but not in others.

Objective

To determine whether female sex is associated with increased mortality risk in SAB.

Data Sources

MEDLINE, Embase, and Web of Science were searched from inception to April 26, 2023.

Study Selection

Included studies met the following criteria: (1) randomized or observational studies evaluating adults with SAB, (2) included 200 or more patients, (3) reported mortality at or before 90 days following SAB, and (4) reported mortality stratified by sex. Studies on specific subpopulations (eg, dialysis, intensive care units, cancer patients) and studies that included patients with bacteremia by various microorganisms that did not report SAB-specific data were excluded.

Data Extraction and Synthesis

Data extraction and quality assessment were performed by 1 reviewer and verified by a second reviewer. Risk of bias and quality were assessed with the Newcastle-Ottawa Quality Assessment Scale. Mortality data were combined as odds ratios (ORs).

Main Outcome and Measures

Mortality at or before 90-day following SAB, stratified by sex.

Results

From 5339 studies retrieved, 89 were included (132 582 patients; 50 258 female [37.9%], 82 324 male [62.1%]). Unadjusted mortality data were available from 81 studies (109 828 patients) and showed increased mortality in female patients compared with male patients (pooled OR, 1.12; 95% CI, 1.06-1.18). Adjusted mortality data accounting for additional patient characteristics and treatment variables were available from 32 studies (95 469 patients) and revealed a similarly increased mortality risk in female relative to male patients (pooled adjusted OR, 1.18; 95% CI, 1.11-1.27). No evidence of publication bias was encountered.

Conclusions and Relevance

In this systematic review and meta-analysis, female patients with SAB had higher mortality risk than males in both unadjusted and adjusted analyses. Further research is needed to study the potential underlying mechanisms.

PCT, IL-6, and IL-10 facilitate early diagnosis and pathogen classifications in bloodstream infection

BACKGROUND

In the diagnosis of bloodstream infection (BSI), various inflammatory markers such as C-reactive protein (CRP), procalcitonin (PCT), interleukins (IL), white blood cell count (WBC), neutrophil percentage (NE%), platelet count (PLT), and erythrocyte sedimentation rate (ESR) have been extensively utilized. However, their specific roles in distinguishing BSI from local bacterial infection (LBI) and in classifying BSI pathogens remain uncertain.

METHODS

A historical cohort study was conducted, involving the enrollment of 505 patients with BSI and 102 patients with LBI. To validate the reliability of the clinical data obtained from this cohort, mouse models of BSI were utilized.

RESULTS

Our findings revealed that patients with BSI had significantly higher levels of inflammatory markers, including CRP, PCT, IL-6, IL-10, WBC, NE%, and ESR, compared to those with LBI (p < 0.05). The receiver operating characteristic (ROC) curve analysis demonstrated that CRP, PCT, IL-6, IL-10, ESR and NE% exhibited excellent diagnostic efficacy for BSI. Additionally, we observed significant differences in CRP, PCT, IL-6, and IL-10 levels between patients with BSI caused by Gram-positive bacteria (GP-BSI) and Gram-negative bacteria (GN-BSI), but no significant variations were found among specific bacterial species. Furthermore, our study also found that CRP, PCT, and IL-10 have good discriminatory ability for vancomycin-resistant Enterococcus (VRE), but they show no significant diagnostic efficacy for other multidrug-resistant organisms (MDROs) such as carbapenem-resistant Enterobacteriaceae (CRE), carbapenem-resistant Pseudomonas aeruginosa (CRPA), and methicillin-resistant Staphylococcus aureus (MRSA). In our mouse model experiments, we observed a remarkable increase in PCT, IL-6, and IL-10 levels in mice with GN-BSI compared to those with GP-BSI.

CONCLUSION

Our study has confirmed that PCT, IL-6, and IL-10 are efficient biomarkers for distinguishing between BSI and LBI. Furthermore, they can be utilized to classify BSI pathogens and differentiate between VRE and vancomycin-susceptible Enterococcus. These findings are extremely valuable for clinicians as they enable timely initiation of empiric antibiotic therapies and ultimately lead to improved clinical outcomes for patients with BSI.

C-reactive protein and the neutrophil-to-lymphocyte ratio on admission predicting bacteraemia with COVID-19

BACKGROUND

Bacteraemia can co-occur with COVID-19. The present study aimed to determine the cut-off value for C-reactive protein (CRP) and the neutrophil-to-lymphocyte ratio (NLR) for predicting bacteraemia in patients with COVID-19.

METHODS

Patients admitted to Tokyo Metropolitan Tama Medical Centre for COVID-19 treatment between 1 April 2020 and 30 October 2022 were included. Patients transferred from other hospitals and those whose CRP and/or neutrophil count was not measured at admission were excluded. Community-acquired bacteraemia was diagnosed if true bacteraemia was diagnosed in patients via a blood culture performed within 72 h of admission. The cut-off value for CRP and the NLR for community-acquired bacteraemia were determined using receiver operating characteristic analysis.

RESULTS

Among 2989 patients hospitalized for COVID-19 treatment, 19 received the diagnosis of community-acquired bacteraemia, for which CRP ≥ 6.3 was determined to be the cut-off value. The sensitivity and specificity of the cut-off was 89.5% and 73.3%, respectively. The NLR cut-off value was ≥ 7.7, which had a sensitivity and specificity of 84.2% and 84.0%, respectively.

CONCLUSIONS

Considering the possibility of the co-occurrence of bacteraemia with COVID-19, a blood culture should be performed when CRP is ≥ 6.3 or the NLR is ≥ 7.7.

Staphylococcus aureus Bacteremia in the Pediatric Emergency Department and Predictors of Poor Outcome

BACKGROUND

Staphylococcus aureus has become the leading cause of bacteremia among previously healthy children older than 5 years.

METHODS

We aimed to describe the infants presenting to pediatric emergency departments and diagnosed with S. aureus bacteremia (SAB) and identify predictors (clinical and laboratory variables) of poor outcome (complications, sequelae or death). We performed an observational study and subanalysis of a multicenter prospective registry, including every patient under the age of 18 years with a positive blood culture obtained at any of the 22 participating Spanish pediatric emergency departments between 2011 and 2016. We considered chronic diseases, immunosuppressive treatment and the presence of mechanical devices as risk factors for SAB.

RESULTS

Of the 229 patients with SAB, 176 (76.9%) were previously healthy, 192 (83.8%) had a normal pediatric assessment triangle and 158 (69.0%) had an associated focal infection (mainly osteoarticular infection, skin and soft tissue infection and pneumonia). Fifty-three patients (23.1%) had 1 or more risk factors for SAB. Thirty-one (13.5%) presented a poor outcome, including 4 deaths (1.7%). A poor outcome was more common in patients with SAB risk factors [odds ratio (OR): 7.0; 95% CI: 3.2-15.4], abnormal PAT (OR: 5.9; 95% CI: 2.6-13.3), elevated procalcitonin (OR: 1.2; 95% CI: 1.05-1.3) and C-reactive protein, the latter being the only independent predictor of poor outcome (OR: 1.01; 95% CI: 1.01-1.02).

CONCLUSIONS

Overall, children with SAB are previously healthy, appear well, and have an associated focal infection. One of 7 had a poor outcome, with C-reactive protein being the only predictor identified.

Predictors of infectious foci on FDG PET/CT in Staphylococcus aureus bacteremia

We looked for predicting factors for the detection of infectious foci on 18F-fluorodeoxyglucose-positron emission tomography in combination with computed tomography (FDG PET/CT) among patients with Staphylococcus aureus bacteremia (SAB) who participated in an interventional study that was conducted at Rambam Health Care Campus, between July 1, 2015 and February 1, 2019. The primary outcome was an infectious focus detected by FDG PET/CT. Independent predictors for detection of focal infection were identified using univariate followed by a logistic regression multivariate analysis. We included 149 patients with 151 separate episodes of SAB who underwent FDG-PET/CT. Focal infections were detected in 107 patients (70.8%). Independent predictors for focal infection detection were community acquisition of bacteremia with odds ratio (OR) 3.03 [95% confidence interval (CI) 1.04-8.77], p-0.042 and C reactive protein (CRP) with OR 1.09 [95% CI 1.04-1.14], p < 0.001. Primary bacteremia was inversely associated with focal infection detection with OR 0.27 [0.10-0.69], p = 0.007, as were the pre-scan blood glucose levels OR 0.9 [0.98-0.99], p-0.004. The latter stayed significant in the subgroup of patients with diabetes mellitus. To conclude, patients with community-acquired bacteremia or high CRP levels should be carefully investigated for focal infection. Patients who present with primary bacteremia seem to be at low risk for focal infection.

Associated Outcomes of Different Intravenous Antibiotics Combined with 2% Mupirocin Ointment in the Treatment of Pediatric Patients with Staphylococcal Scalded Skin Syndrome

Purpose

To compare treatment duration, influencing factors, and costs among intravenous antibiotic groups combined with 2% mupirocin ointment for treating staphylococcal scalded skin syndrome (SSSS).

Patients and Methods

Sex, age, onset days before admission, febrile status, white blood cell (WBC) count, and C-reactive protein (CRP) level were recorded as baseline characteristics for 253 included patients. The antibiotic sensitivity results were statistically compared by Cochran's Q test. Kruskal-Wallis tests were used to compare days and the total costs of hospitalization with different intravenous antibiotic applications. Mann-Whitney U-tests or Spearman's rank correlation tests were used for the univariate analysis. Finally, a multivariate linear regression model was employed to determine the variables with statistical significance.

Results

The sensitivity rates of oxacillin (84.62%), vancomycin (100%), and mupirocin (100%) were significantly higher than those of clindamycin (7.69%) (p<0.0001). The duration of intravenous ceftriaxone administration was significantly longer than that of amoxicillin-clavulanic acid, cefathiamidine, and cefuroxime (p<0.01). The total hospitalization costs for cefathiamidine were significantly higher than those for amoxicillin-clavulanic acid and cefuroxime (p<0.05). According to the multiple linear regression, ages ≥60 months old were correlated with shorter treatment duration (β=-1.48, [95% CI: -2.29, -0.66] for amoxicillin-clavulanic acid, and β=-1.44, [95% CI: -2.06, -0.83] for cefathiamidine, and β=-0.96, [95% CI: -1.58, -0.34] for cefuroxime) (all p<0.01). In multivariate analysis for cefathiamidine, higher WBC count (β=0.05, [95% CI: 0.01, 0.10], p<0.05) and CRP level (β=1.12, [95% CI: 0.14, 2.10], p<0.05) were associated with longer treatment course.

Conclusion

Oxacillin resistance was rare, and clindamycin resistance was high in pediatric patients with SSSS in our district. Intravenous amoxicillin-clavulanic acid and cefuroxime combined with topical mupirocin were favorable due to a shorter intravenous treatment course and lower costs. Younger age, elevated WBC count, and CRP levels could indicate a longer course of treatment with intravenous antibiotics.

C-reactive protein predicts persistent bacteremia caused by community-acquired methicillin-resistant Staphylococcus aureus strain

There is limited data on persistent bacteremia (PB) caused by community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA). Here, we aimed to investigate the clinical and microbiological characteristics of PB caused by the major CA-MRSA strain in Korea (ST72-SCCmecIV). All adult patients with S. aureus bacteremia were prospectively investigated from August 2008 to December 2018. Patients with ST72 MRSA bacteremia were included in the study. Patients were stratified into the PB group (defined as positive blood cultures for ≥ 3 days) and short bacteremia (SB) group. A total of 291 patients were included, comprising 115 (39.5%) with PB and 176 (60.5%) with SB. Although the 30-day mortality did not differ between PB and SB, recurrent bacteremia within 12 weeks was significantly more common in PB (8.7% vs 1.7%; P = 0.01). Multivariate analysis showed risk factors of PB were liver cirrhosis (adjusted odds ratio [aOR], 3.27; 95% confidence interval [CI], 1.50-7.12), infective endocarditis (aOR, 7.13; 95% CI, 1.37-37.12), bone and joint infections (aOR, 3.76; 95% CI, 1.62-8.77), C-reactive protein ≥ 10 mg/dL (aOR, 2.20; 95% CI, 1.22-3.95), metastatic infection (aOR, 7.35; 95% CI, 3.53-15.29), and agr dysfunction (aOR, 2.47; 95% CI, 1.05-5.81). PB occurred in approximately 40% of bacteremia caused by ST72 MRSA with a significantly higher recurrence rate. Patients with risk factors of PB, including liver cirrhosis, high initial CRP, infective endocarditis, or bone and joint infections, might require early aggressive treatment.

C-reactive protein predicts complications in community-associated S. aureus bacteraemia: a cohort study

Background

Staphylococcus aureus (S. aureus) bacteraemia is increasingly acquired from community settings and is associated with a mortality rate of up to 40% following complications. Identifying risk factors for complicated S. aureus bacteraemia would aid clinicians in targeting patients that benefit from expedited investigations and escalated care.

Methods

In this prospective observational cohort study, we aimed to identify risk factors associated with a complicated infection in community-onset S. aureus bacteraemia. Potential risk factors were collected from electronic medical records and included: - patient demographics, symptomology, portal of entry, and laboratory results.

Results

We identified several potential risk factors using univariate analysis. In a multiple logistic regression model, age, haemodialysis, and entry point from a diabetic foot ulcer were all significantly protective against complications. Conversely, an unknown entry point of infection, an entry point from an indwelling medical device, and a C-reactive protein concentration of over 161 mg/L on the day of admission were all significantly associated with complications.

Conclusions

We conclude that several factors are associated with complications including already conducted laboratory investigations and portal of entry of infection. These factors could aid the triage of at-risk patients for complications of S. aureus bacteraemia.

The Degree of Blood Supply and Infection Control Needed to Treat Diabetic Chronic Limb-Threatening Ischemia with Forefoot Osteomyelitis

BACKGROUND

Diabetic foot ulcers combined with ischemia and infection can be difficult to treat. Few studies have quantified the level of blood supply and infection control required to treat such complex diabetic foot ulcers. We aimed to propose an index for ischemia and infection control in diabetic chronic limb-threatening ischemia (CLTI) with forefoot osteomyelitis.

METHODS

We retrospectively evaluated 30 patients with diabetic CLTI combined with forefoot osteomyelitis who were treated surgically from January 2009 to December 2016. After 44 surgeries, we compared patient background (age, sex, hemodialysis), infection status (preoperative and 1- and 2-week postoperative C-reactive protein [CRP] levels), surgical bone margin (with or without osteomyelitis), vascular supply (skin perfusion pressure), ulcer size (wound grade 0-3 using the Society for Vascular Surgery Wound, Ischemia, and foot Infection classification), and time to wound healing between patients with healing ulcers and those with nonhealing ulcers.

RESULTS

Preoperative CRP levels and the ratio of ulcers classified as wound grade 3 were significantly lower and skin perfusion pressure was significantly higher in the healing group than in the nonhealing group (P < .05). No other significant differences were found between groups.

CONCLUSIONS

This study demonstrates that debridement should be performed first to control infection if the preoperative CRP level is greater than 40 mg/L. Skin perfusion pressure of 55 mm Hg is strongly associated with successful treatment. We believe that this research could improve the likelihood of salvaging limbs in patients with diabetes with CLTI.

Early differentiation between uncomplicated and complicated Staphylococcus aureus bacteraemia: Potential value and limitations of a clinical risk score

OBJECTIVE

A cornerstone in the management of Staphylococcus aureus bacteraemia (SAB) is the differentiation between a complicated and an uncomplicated SAB course. The ability to early and accurately identify patients with - and without - complicated bacteraemia may optimise the utility of diagnostics and prevent unnecessary prolonged antibiotic therapy.

METHODS

Development and validation of a prediction score in SAB using demographic, clinical, and laboratory data from two independent Dutch cohorts; estimating the risk of complicated disease at the time of the first positive blood culture. Models were developed using logistic regression and evaluated by c-statistics, ie area under the ROC-curve, and negative predictive values (NPV).

RESULTS

The development- and validation cohorts included 150 and 183 patients, respectively. The most optimal prediction model included: mean arterial pressure, signs of metastatic infection on physical examination, leucocyte count, urea level and time to positivity of blood cultures (c-statistic 0.82, 95% CI 0.74-0.89). In the validation cohort, the c-statistic of the prediction score was 0,77 (95% CI 0.69-0.84). The NPV for complicated disease for patients with a score of ≤2 was 0.83 (95% CI 0.68-0.92), with a negative likelihood ratio of 0.14 (95% CI 0.06-0.31).

CONCLUSION

The early SAB risk score helps to identify patients with high probability of uncomplicated SAB. However, the risk score's lacked absolute discriminative power to guide decisions on the management of all patients with SAB on its own. The heterogenicity of the disease and inconsistency in definitions of complicated SAB are important challenges in the development of clinical rules to guide the management of SAB.