Rapid and accurate identification of Staphylococcus aureus (SA) in blood culture specimens is crucial for timely clinical intervention. Traditional Gram staining methods, although widely accessible and cost-effective, exhibit variable sensitivities and specificities in the BACTEC system. We aimed to develop and validate the \"STAPH score,\" a novel semi-quantitative scoring system that integrates Gram stain morphology and time to positivity to differentiate SA from coagulase-negative staphylococci (CoNS) in blood cultures. We analyzed 148 blood culture specimens from septic patients. Each specimen was assessed independently by two examiners using Gram staining and the STAPH score, which assigns points based on five parameters: cluster size, time to positivity, aerobic enlargement, pint (three-dimensional appearance), and the presence of hemorrhage. Sensitivity and specificity were calculated for various cutoff points. Cohen\'s kappa coefficient was used to assess inter-examiner agreement. Of the 148 specimens, 49 (33.1%) were identified as SA and 99 (66.9%) as CoNS. At a STAPH score cutoff of 3 points, the sensitivity was 93.9% (95% confidence interval [CI], 83.1%-98.7%) and specificity was 91.9% (95% CI, 84.7%-96.4%). The kappa coefficient at this cutoff was 0.67 (95% CI, 0.55-0.79). A STAPH score <3 effectively ruled out SA with 100% sensitivity, whereas a score of 5 confirmed SA with 100% specificity. The STAPH score is a reliable and efficient tool for the rapid identification of SA in blood cultures within the BACTEC system. By combining Gram staining observations with time to positivity, this method enhances diagnostic accuracy, reduces subjectivity, and supports timely clinical decision-making.IMPORTANCEThe rapid and accurate identification of Staphylococcus aureus (SA) in blood cultures is vital for timely and appropriate clinical intervention. This study introduces the \"STAPH score,\" a novel semi-quantitative scoring system that combines Gram stain morphology and time to positivity. By providing a reliable and efficient method to differentiate SA from coagulase-negative staphylococci, the STAPH score enhances diagnostic accuracy and reduces subjectivity in microscopic examinations. This score, applicable within the BACTEC system, addresses the limitations of traditional Gram staining methods and expensive molecular techniques. The implementation of the STAPH score in clinical practice can lead to faster diagnosis, improved patient outcomes, and optimized antimicrobial therapy. This method is particularly valuable in resource-limited settings where advanced diagnostic tools may not be available.

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We discuss a case where the blood cultures of a patient with clinical chorioamnionitis and elevated D-dimer levels enabled early diagnosis of infective endocarditis. A 31-year-old female with a 39-week pregnancy presented to the obstetrics department with a fever. Cardiotocography revealed fetal tachycardia and severe late deceleration. Preoperative examinations revealed a leukocyte count of 15,900/μL and D-dimer levels of 86.2 μg/mL. She was diagnosed with a non-reassuring fetal status due to clinical chorioamnionitis; accordingly, an emergency cesarean section was performed. Imaging studies ruled out the possibility of a thromboembolism. Subsequent maternal blood cultures were positive for Staphylococcus aureus. Echocardiography revealed vegetation on the aortic valve, leading to a diagnosis of infective endocarditis. Blood cultures can be useful in evaluating for sepsis in cases of clinical chorioamnionitis with elevated D-dimer levels as they may facilitate early diagnosis of infective endocarditis during pregnancy.

Staphylococcus aureus bacteremia causes significant morbidity and mortality. Treatment of staphylococcal infections is hindered by widespread antibiotic resistance, and attempts to develop an S. aureus vaccine have failed. Improved S. aureus treatment and infection prevention options require a deeper understanding of the correlates of protective immunity. CD4+ T cells have been identified as key orchestrators in the defense against S. aureus, but uncertainties persist regarding the subset, polarity, and breadth of the memory CD4+ T-cell pool required for protection. Here, using a mouse model of systemic S. aureus infection, we discovered that the breadth of bacterium-specific memory CD4+ T-cell pool is a critical factor for protective immunity against invasive S. aureus infections. Seeding mice with a monoclonal bacterium-specific circulating memory CD4+ T-cell population failed to protect against systemic S. aureus infection; however, the introduction of a polyclonal and polyfunctional memory CD4+ T-cell pool significantly reduced the bacterial burden. Our findings support the development of a multi-epitope T-cell-based S. aureus vaccine, as a strategy to mitigate the severity of S. aureus bacteremia.

UNASSIGNED: This paper aims to determine the Staphylococcus aureus bacteremia (SAB) in-hospital mortality rate and its associated risk factors during the COVID-19 pandemic.
UNASSIGNED: A total of 167 SAB samples were collected between March 2020 and March 2022 at a teaching hospital in Tehran, Iran. The patient\'s baseline data and antibiograms were collected. The outcome of the study was in-hospital mortality.
UNASSIGNED: The overall in-hospital mortality rate was 41.9 %, with higher mortality observed in patients over 60 years old (P = 0.032), those with community-acquired Staphylococcus aureus bacteremia (P = 0.010), and those admitted to the ICU (P = 0.016). Antibiotic resistance profiles indicated a higher mortality in resistant S.aureus strains but only significant for ciprofloxacin (P = 0.001), methicillin (P = 0.047), and sulfamethoxazole (P = 0.023). Multivariate analysis identified age, sex, ICU admission, and the source of bacteremia as independent predictors of mortality, while COVID-19 coinfection and resistance to antibiotics were not found to be significant predictors.
UNASSIGNED: SAB remains a challenging infection that is amplified by the pandemic. Older age and ICU admission are significant mortality predictors. In settings with a high prevalence of MRSA, factors like age, sex, and quality of care outweigh pathogen-related factors such as antibiotic resistance.

BACKGROUND: Empyema necessitans (EN) is a rare condition characterized by pleural infection with pus spreading into adjacent soft tissues. Although Mycobacterium tuberculosis and Actinomyces israelii are common causative agents, methicillin-resistant Staphylococcus aureus (MRSA) is relatively rare, but it is associated with high mortality in empyema cases. We aimed to report a unique case of EN caused by MRSA and present a literature review to better understand this rare condition.
METHODS: A 69-year-old man with a history of right ureteral stone presented with fever and left anterior thoracic pain. A physical examination revealed redness and swelling in the left thoracic region. Imaging studies confirmed EN with fluid accumulation around the sternocostal joint of the left first rib. MRSA was identified from blood and pleural fluid cultures. The patient received antimicrobial therapy, and a chest tube was inserted for drainage. Despite initial improvement, vertebral osteomyelitis was diagnosed on day 17. The antimicrobials were subsequently terminated after 6 weeks, but vertebral osteomyelitis recurred, and treatment was resumed and completed on day 215.
CONCLUSIONS: EN caused by MRSA is rare, and the literature review revealed 14 cases from human sources. Positive blood cultures were observed in 40% of cases, and metastatic infections were present in 30% of cases. Osteomyelitis was the most common type of metastatic lesion. All the patients underwent drainage. Patients with MRSA-associated EN frequently develop disseminated lesions and should therefore be carefully examined. Moreover, appropriate treatment with antibiotics and drainage is necessary for a good prognosis. Although the prognosis appeared to be favorable in our review, publication bias and treatment challenges for metastatic infections should be considered.

Staphylococcus aureus bacteremia (SAB) is one of the most common serious bacterial infections worldwide. In this study, we demonstrated changes in SAB epidemiology in an Argentinean University Hospital during an 8-year period (2009-2016). A total of 326 S. aureus clinical isolates were recovered in three periods: P1: 2009-2010, P2: 2012-2014, and P3: 2015-2016. Among these, 127 were methicillin-resistant S. aureus (MRSA) and were characterized by phenotypic and molecular methods. We hereby report a significant decline in multiple drug resistance among MRSA isolates associated with an increase in SCCmec IV between the three periods. A diversity of MRSA-IV clones (mainly ST30-MRSA-IV, ST5-MRSA-IV, and ST8-MRSA-IV) replaced between 2009 and 2016 the previous prevalent MRSA clone causing bloodstream infections at this hospital (ST5-MRSA-I). MRSA population structure continued to diversify between P2 and P3. Notably, ST8-MRSA-IV-t008 related to USA300 was first detected during P2, and ST8-MRSA-IV together with ST30-MRSA-IV related to the Southwest Pacific clone were the more prevalent MRSA genotypes circulating during P3.

Infective endocarditis (IE) is a serious and potentially life-threatening infection of the heart valves. It is commonly treated with prolonged courses of intravenous antibiotics, and in some cases, surgical intervention may also be necessary. While the use of oral antibiotics in the treatment of IE is generally limited, there are select cases where they may be considered as an alternative treatment option. Here, we report a case of staphylococcal right-sided IE successfully treated with oral antibiotics (linezolid and rifampicin). Our case highlights the potential for oral antibiotics to be used as step-down therapy for select patients with IE.

UNASSIGNED: The Combination Antibiotic Therapy for Methicillin-Resistant Staphylococcus aureus (CAMERA2) trial ceased recruitment in July 2018, noting that a higher proportion of patients in the intervention arm (combination therapy) developed acute kidney injury (AKI) compared to the standard therapy (monotherapy) arm. We analyzed the long-term outcomes of participants in CAMERA2 to understand the impact of combination antibiotic therapy and AKI.
UNASSIGNED: Trial sites obtained additional follow-up data. The primary outcome was all-cause mortality, censored at death or the date of last known follow-up. Secondary outcomes included kidney failure or a reduction in kidney function (a 40% reduction in estimated glomerular filtration rate to <60 mL/minute/1.73 m2). To determine independent predictors of mortality in this cohort, adjusted hazard ratios were calculated using a Cox proportional hazards regression model.
UNASSIGNED: This post hoc analysis included extended follow-up data for 260 patients. Overall, 123 of 260 (47%) of participants died, with a median population survival estimate of 3.4 years (235 deaths per 1000 person-years). Fifty-five patients died within 90 days after CAMERA2 trial randomization; another 68 deaths occurred after day 90. Using univariable Cox proportional hazards regression, mortality was not associated with either the assigned treatment arm in CAMERA2 (hazard ratio [HR], 0.84 [95% confidence interval [CI], .59-1.19]; P = .33) or experiencing an AKI (HR at 1 year, 1.04 [95% CI, .64-1.68]; P = .88).
UNASSIGNED: In this cohort of patients hospitalized with methicillin-resistant S aureus bacteremia, we found no association between either treatment arm of the CAMERA2 trial or AKI (using CAMERA2 trial definition) and longer-term mortality.

Non-traumatic mediastinal abscesses are very rare in children; we can classify them into 2 types: descending mediastinitis (or mediastinitis by extension or by contiguity) complicating an otorhinolaryngological or esophageal etiology and mediastinitis generated by direct blood inoculation in a context of a septicemia or primary mediastinitis which is exceptional. We describe a case of right pleuropulmonary staphylococcal disease with bilateral mediastinal localization in a previously healthy 9-month-old infant. It was revealed by sepsis with severe respiratory distress. The germ was isolated from the pleural puncture fluid. A thoracic computed tomography was indicated due to a widening mediastinum noted on chest X-ray in addition to pleuropulmonary involvement. Thoracic computed tomography revealed a huge bilateral mediastinal abscess which was curbed thanks to right pleural drainage with adapted antibiotic therapy. Other investigations did not show any immune abnormalities in this infant. Mediastinitis represents a diagnostic and therapeutic emergency; those that are secondary to direct blood or lymphatic dissemination even very rare; should be considered in any context of severe sepsis including staphylococcus or streptococcus pneumonia. Since 1985 only 11 cases of such mediastinal abscesses have been reported.