Background: PJIs following total hip and knee arthroplasty represent severe complications with broad implications, and with significant disability, morbidity, and mortality. To be able to provide correct and effective management of these cases, an accurate diagnosis is needed. Classically, acute PJIs are characterized by a preponderance of virulent microorganisms, and chronic PJIs are characterized by a preponderance of less-virulent pathogens like coagulase-negative staphylococci or Cutibacterium species. This paper aims to analyze if there are any changes in the causative microorganisms isolated in the last years, as well as to provide a subanalysis of the types of PJIs. Methods: In this single-center study, we prospectively included all retrospectively consecutive collected data from patients aged over 18 years that were hospitalized from 2016 through 2022, and patients that underwent a joint arthroplasty revision surgery. A standardized diagnostic protocol was used in all cases, and the 2021 EBJIS definition criteria for PJIs was used. Results: 114 patients were included in our analysis; of them, 67 were diagnosed with PJIs, 12 were acute/acute hematogenous, and 55 were chronic PJIs. 49 strains of gram-positive aerobic or microaerophilic cocci and 35 gram-negative aerobic bacilli were isolated. Overall, Staphylococcus aureus was the most common isolated pathogen, followed by coagulase-negative staphylococci (CoNS). All cases of acute/acute hematogenous PJIs were caused by gram-positive aerobic or microaerophilic cocci pathogens. Both Staphylococcus epidermidis and methicillin-resistant S. aureus were involved in 91.66% of the acute/acute hematogenous PJIs cases. 21.8% of the chronic PJIs cases were caused by pathogens belonging to the Enterobacterales group of bacteria, followed by the gram-negative nonfermenting bacilli group of bacteria, which were involved in 18.4% of the cases. 12 chronic cases were polymicrobial. Conclusion: Based on our findings, empiric broad-spectrum antibiotic therapy in acute PJIs could be focused on the bacteria belonging to the gram-positive aerobic or microaerophilic cocci, but the results should be analyzed carefully, and the local resistance of the pathogens should be taken into consideration.

Beside the changes in the gut microbiota in context of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, the increased use of high-risk broad-spectrum antibiotics during the actual pandemic raises concerns about a possible increase of Clostridioides difficile infections (CDIs). We retrospectively analyzed 80 consecutive patients, with SARS-CoV-2 pneumonia and CDI. The mean length of hospitalization was 19.63 days. The mean time of the onset of the digestive symptoms related to CDI was 5.16 days. Patients with an onset of the digestive symptoms from hospital admission have a significantly lower median length in hospital stay. The recovered patients present a statistically significant decreased median age. coronavirus disease 2019 (COVID-19) cured patients present CDI symptoms much earlier than the deceased patients, when comparing the median days before the occurrence of any digestive symptoms regarding CDI. Among the patients that prior to their hospitalization for COVID-19 were exposed to antibiotics, 54.7% presented CDI digestive symptoms during their hospitalization and 65.6% had a severe or critical COVID-19 form. Although the incidence of CDI in the pandemic is lower compared to the period before the pandemic, the severity of cases and the death rate increased. In the actual setting clinicians need to be aware of possible CDI and SARS-CoV-2 co-infection.

Background/Objectives: Periprosthetic joint infection (PJI) remains one of the most devastating complications of arthroplasty, with early diagnosis crucial for successful management. The serum neutrophil–lymphocyte ratio (NLR) and monocyte–lymphocyte ratio (MLR) have been proposed as simple, inexpensive inflammatory biomarkers, but their diagnostic performance in PJI remains unclear. This meta-analysis aimed to compare the diagnostic accuracy of serum NLR and MLR in detecting PJI. Materials and Methods: A systematic literature search was conducted in PubMed, Web of Science, and Scopus up to April 2025. Twenty-nine eligible studies (n = 14,040 patients; 3418 with PJI, 10,622 without PJI) reporting diagnostic metrics for serum NLR or MLR were included. Extracted data comprised mean biomarker values, cut-off thresholds, sensitivity, specificity, and area under the receiver operating characteristic curve (AUC). Non-parametric statistical tests and subgroup analyses were applied to examine performance across infection types and PJI definitions. Results: Both serum NLR and MLR were significantly elevated in PJI patients compared with aseptic cases (p < 0.001 and p = 0.003, respectively). Pooled diagnostic accuracy was moderate: mean AUC 0.719 for NLR and 0.700 for MLR. For NLR, mean sensitivity was 69.9% and specificity 69.8%, with an average cut-off of 2.88. For MLR, mean sensitivity was 68.2% and specificity 70.4%, with an average cut-off of 0.34. Subgroup analyses indicated superior diagnostic performance of NLR in acute infections and variability depending on the PJI definition employed (p = 0.037). Strong correlations were observed between standardized mean differences in biomarker levels and corresponding diagnostic accuracy, particularly for NLR (ρ = 0.802, p = 0.002). Conclusions: Serum NLR demonstrates slightly superior diagnostic accuracy over serum MLR in identifying PJI, especially in acute settings. Both markers are inexpensive and widely accessible but show only moderate discriminative capacity, supporting their role as adjunctive rather than standalone diagnostic tools. Further large-scale prospective studies with harmonized methodologies are needed to refine biomarker thresholds and integrate them into multimodal diagnostic algorithms.