Surgery for Active Infective Endocarditis on Mitral Valve: Anatomical, Surgical, and Disease Factors as Long-Term Outcome Modifiers.

Background and Objectives: Determinants of long-term outcomes after surgery for native mitral valve endocarditis have not been thoroughly investigated. The aim of this study was to assess anatomical, disease, and surgical risk factors for long-term mortality and need of reintervention, in patients undergoing mitral valve surgery for active endocarditis. Materials and Methods: Patients who underwent surgery for active native mitral valve endocarditis at three academic centres, between 2000 and 2022, were analysed. The primary outcome was long-term survival. The secondary outcome was the freedom from mitral reoperation. Survival curves were constructed with Kaplan-Meier methodology. Multivariable Cox regression was used to identify demographic, anatomical, disease, and surgical factors associated with late mortality and reoperation. Results: 335 consecutive patients with active mitral endocarditis were analysed. Two hundred and one patients (70.5%) had infection confined to the valve cusp whereas 89 (25.6%) had invasive disease extended to the annulus and surrounding tissues. Preoperative neurological events occurred at the diagnosis in 52 cases. Streptococci were the most common causative organisms followed by Staphylococcus aureus, Coagulase-negative Staphylococcus, and Enterococcus. Valve repair was performed in 108 patients (32.2%). Survival at 5 and 10 years was 70.1% and 59.2%, respectively. Staphylococcus emerged as an independent predictor of late mortality, along with age, chronic obstructive pulmonary disease, and previous cardiac surgery. Survival was considerably reduced in patients with S. aureus compared with those without (log rank p < 0.001). The type of surgery (repair vs. replacement) did not emerge as a risk factor for late mortality and reoperation. Seventeen patients underwent mitral reoperation during the follow-up. The 5- and 10-year freedom from reoperation was 94.7% and 91.8%, respectively. Conclusions: Active mitral valve endocarditis remains a life-threatening disease with impaired survival. While lesion characteristics influenced surgical decision-making and intraoperative management, their impact on long-term survival and freedom from reintervention appears to be moderated by other factors such as infecting pathogens and patient comorbidities.

A 12-Year Retrospective Analysis of Blood Culture Isolates in the Intensive Care Unit of a Tertiary Hospital in China.

BACKGROUND: This paper is to explore the composition and antibiotic resistance of pathogens isolated from blood cultures of patients with bloodstream infection (BSI) in the intensive care unit (ICU). METHODS: A retrospective study has been performed to identify the pathogens isolated from blood cultures of 147 patients with BSI in the ICU of our Hospital over 12 years (January 2008 to December 2019). The antibiotic resistance and susceptibility of the isolates were tested. RESULTS: Among the 152 pathogens isolated from positive blood cultures, 61.84% were Gram-positive bacteria, 34.87% were Gram-negative bacteria, and 3.29% were fungi. The most frequently isolated pathogens were coagulase-negative Staphylococci, Staphylococcus aureus, and Escherichia coli. The pathogen distributions remained stable over 12 years. Gram-positive cocci were highly susceptible to vancomycin, linezolid, and teicoplanin. Extended-spectrum ß-lactamase-producing pathogens were highly susceptible to amikacin, imipenem, meropenem, and polymyxin B. Acinetobacter were relatively sensitive to amikacin, trimethoprim-sulfamethoxazole, and polymyxin, whereas Pseudomonas aeruginosa were sensitive to amikacin, gentamicin, levofloxacin, imipenem, meropenem, and ciprofloxacin, with resistance rates less than 30%. CONCLUSIONS: Gram-positive bacteria were the dominant pathogens isolated from blood cultures of ICU-BSI patients and were susceptible to vancomycin, linezolid, and teicoplanin. The antibiotic susceptibility of Gram-negative bacteria varies greatly. Our results provide important information to guide the treatment decisions in the management of ICU-BSIs.

Detecting the performance of methicillin-resistant Staphylococcus aureus by a molecular diagnostic assay in positive blood culture: Influence of coexistence of mecA-positive bacteria and diversity in orfX-SCCmec junction region in methicillin-susceptible S. aureus.

BACKGROUND: In blood cultures that test positive for staphylococcal bacteria, rapid identification of methicillin-resistant Staphylococcus aureus (MRSA) or methicillin-susceptible Staphylococcus aureus (MSSA) by molecular assay is useful for appropriate antimicrobial treatment of bloodstream infections. Although the Xpert MRSA/SA BC assay is widely available in clinical settings in Japan, its efficacy has not yet evaluated thoroughly. METHODS: We retrospectively studied 100 blood culture cases positive for S. aureus at Sapporo Medical University Hospital between March 2019 and May 2022. Cycle threshold (CT) values for target genes from the Xpert MRSA/SA BC assay were compared to phenotypic results. Genotyping and genetic analysis of the orfX-SCCmec junction region was performed for selected isolates. RESULTS: We analyzed 25 and 75 isolates assigned to MRSA and MSSA, respectively, using the Xpert MRSA/SA BC assay. Of these, 99 isolates from agar cultures showed compatible susceptibility to oxacillin. One genetically misidentified case of MRSA was found to be caused by the mixed growth of MSSA and methicillin-resistant S. hominis on agar culture. Of the 73 MSSA with pure growth on agar culture, 45 (61.6%) were found to be orfX-SCCmec-positive, spa-positive, and mecA-negative in this assay. These MSSA belong to diverse spa and coa types. CONCLUSION: The Xpert MRSA/SA BC assay accurately identified MRSA and MSSA in positive blood cultures. However, over half of the MSSA isolates showed positive results for orfX-SCCmec, presumably due to genetic diversity in the orfX-associated region of MSSA. Therefore, the coexistence of MSSA and mecA-harboring coagulase-negative staphylococci may cause confusion about identification of MRSA.

Partial Oral versus Intravenous Antibiotic Treatment of Endocarditis.

BACKGROUND: Patients with infective endocarditis on the left side of the heart are typically treated with intravenous antibiotic agents for up to 6 weeks. Whether a shift from intravenous to oral antibiotics once the patient is in stable condition would result in efficacy and safety similar to those with continued intravenous treatment is unknown. METHODS: In a randomized, noninferiority, multicenter trial, we assigned 400 adults in stable condition who had endocarditis on the left side of the heart caused by streptococcus, Enterococcus faecalis, Staphylococcus aureus, or coagulase-negative staphylococci and who were being treated with intravenous antibiotics to continue intravenous treatment (199 patients) or to switch to oral antibiotic treatment (201 patients). In all patients, antibiotic treatment was administered intravenously for at least 10 days. If feasible, patients in the orally treated group were discharged to outpatient treatment. The primary outcome was a composite of all-cause mortality, unplanned cardiac surgery, embolic events, or relapse of bacteremia with the primary pathogen, from the time of randomization until 6 months after antibiotic treatment was completed. RESULTS: After randomization, antibiotic treatment was completed after a median of 19 days (interquartile range, 14 to 25) in the intravenously treated group and 17 days (interquartile range, 14 to 25) in the orally treated group (P=0.48). The primary composite outcome occurred in 24 patients (12.1%) in the intravenously treated group and in 18 (9.0%) in the orally treated group (between-group difference, 3.1 percentage points; 95% confidence interval, -3.4 to 9.6; P=0.40), which met noninferiority criteria. CONCLUSIONS: In patients with endocarditis on the left side of the heart who were in stable condition, changing to oral antibiotic treatment was noninferior to continued intravenous antibiotic treatment. (Funded by the Danish Heart Foundation and others; POET ClinicalTrials.gov number, NCT01375257 .).

Secondary infections worsen the outcome of COVID-19 in patients with hematological malignancies: A report from the ITA-HEMA-COV.

The impact of secondary infections (SI) on COVID-19 outcome in patients with hematological malignancies (HM) is scarcely documented. To evaluate incidence, clinical characteristics, and outcome of SI, we analyzed the microbiologically documented SI in a large multicenter cohort of adult HM patients with COVID-19. Among 1741 HM patients with COVID-19, 134 (7.7%) had 185 SI, with a 1-month cumulative incidence of 5%. Median time between COVID-19 diagnosis and SI was 16 days (IQR: 5-36). Acute myeloid leukemia (AML) and lymphoma/plasma cell neoplasms (PCN) were more frequent diagnoses in SI patients compared to patients without SI (AML: 14.9% vs. 7.1%; lymphoma/PCN 71.7% vs. 65.3%). Patients with SI were older (median age 70 vs. 66 years, p = 0.002), with more comorbidities (median Charlson Comorbidity Index 5 vs. 4, p < 0.001), higher frequency of critical COVID-19 (19.5% vs. 11.5%, p = 0.046), and more frequently not in complete remission (75% vs. 64.7% p = 0.024). Blood and bronchoalveolar lavage were the main sites of isolation for SI. Etiology of infections was bacterial in 80% (n = 148) of cases, mycotic in 9.7% (n = 18) and viral in 10.3% (n = 19); polymicrobial infections were observed in 24 patients (18%). Escherichia coli represented most of Gram-negative isolates (18.9%), while coagulase-negative Staphylococci were the most frequent among Gram-positive (14.2%). The 30-day mortality of patients with SI was higher when compared to patients without SI (69% vs. 15%, p < 0.001). The occurrence of SI worsened COVID-19 outcome in HM patients. Timely diagnosis and adequate management should be considered to improve their prognosis.

Staphylococcus massiliensis isolated from human blood cultures, Germany, 2017-2020.

Clinical and laboratory data on newly described staphylococcal species is rare, which hampers decision-making when such pathogens are detected in clinical specimens. Here, we describe Staphylococcus massiliensis detected in three patients at a university hospital in southwest Germany. We report the discrepancy of microbiological findings between matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, 16S-rRNA polymerase chain reaction, and whole-genome sequencing for all three isolates. Our findings highlight the diagnostic pitfalls pertinent to novel and non-model organisms in daily microbiological practice, in whom the correct identification is dependent on database accuracy.

Rapid Bacterial Identification and Drug Sensitivity Test Methods for Pathogens in Positive Blood Cultures.

BACKGROUND: The turnover time of positive blood culture using traditional methods takes too long. This study aimed to evaluate rapid direct identification and drug sensitivity test methods for pathogens in positive blood cultures. METHODS: A total of 403 blood culture bottles were used to compare the rapid identification methods and drug sensitivity tests for pathogens causing bloodstream infections. Bacteria were enriched using separator gel tubes and were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. In addition, bacteria were also identified using an established traditional method for comparison. The sensitivity of gram-negative bacilli against antibiotics was tested using Rapid Bacterial Test Strips or the VITEK 2 Compact system. RESULTS: The accuracy was 81.8% in 403 bacteria, of which 71% (132/186) and 96.3% (209/217) were gram-positive and gram-negative bacteria, respectively. The gram-positive bacteria were primarily Staphylococcus aureus and coagulase-negative Staphylococcus. The gram-negative bacteria were primarily Escherichia coli and Klebsiella pneumonia. Compared with routine drug sensitivity testing methods, the coincidence rate of direct drug sensitivity testing for classifying the bacteria was 98.6% (1,325/1,344). The average rapid bacterial identification time was 1.5 hours, and the direct drug sensitivity test took - 8.5 hours. CONCLUSIONS: The present study showed that direct identification and rapid drug sensitivity testing can be performed on the same day and can be completed 1 or 2 days ahead of routine methods, thereby assisting in providing earlier drug options for anti-infective therapy.

Molecular testing with next-generation sequencing appears to identify biofilm on penile prostheses better than traditional cultures: The new gold standard?

INTRODUCTION: Traditional culture is the current standard-of-care to determine therapeutic antibiotics for patients suffering from penile prostheses (PP) infections. However, approximately 50% of PPs removed for infection are culture negative. Next-generation sequencing (NGS) compares DNA sequences to reference sequences with known microbial taxonomies to identify isolates and report relative abundances. We aim to compare the ability for standard culture and NGS techniques to identify microorganisms and biofilm composition on PPs. MATERIALS AND METHODS: Ninety-one PPs explanted for mechanical malfunction were included in this study. Devices removed for infection or erosion were excluded. During revision surgery, two specimens were collected and sent for culture testing at institutional laboratory and for NGS testing (MicroGenDx, Lubbock, TX, USA). Species' relative abundances, sample diversity and richness, and compositional differences among samples were analyzed. RESULTS: NGS had a higher rate of microbial detection (n = 72, 79.1%) compared to culture results (n = 3, 3.3%). Some of the bacteria identified using both methods were known prosthetic infectious pathogens, with NGS producing more isolates (mean: 11) than culture (mean: 1). Escherichia coli was the most abundant and most frequently occurring bacteria detected on NGS. Coagulase-negative Staphylococci were the most common bacteria detected on traditional culture. CONCLUSIONS: NGS appears to be beneficial in its thorough analysis of PP biofilm composition when compared to culture methods. We hope that further research will be able to demonstrate a clinical benefit of NGS in characterizing distinct microbiomes and biofilms of infected PP, which can aid in tailoring antimicrobial therapy and improving patient outcomes.

Laboratory diagnosis of community-acquired bloodstream infection in therapeutic pathology.

Community-acquired bloodstream infections (CBSIs) occur in the out-of-hospital setting (44%) and increase the overall mortality from bloodstream infections (BSIs) by 7.2% per year. The development of CBSIs depends on both comorbid and polymorbid diseases and the patients' age. The causes of CBSIs are: respiratory, hepatobiliary gastrointestinal and urogenital tracts and dental interventions. The etiology of CBSIs is characterized by the isolation of coagulase-negative staphylococci (CNS) (32%), E. coli (27%). To investigate community-acquired bloodstream infection in therapeutic patients. The study included out-of-hospital patients (n=382). 4.5 ml of blood were taken intravenously into a closed vacuum system in order to obtain a buffy coat of blood, which was put on glasses for microscopy and Petri dishes with blood agar for cultivating under aerobic and anaerobic conditions. Microorganisms were identified by mass spectrometry. Microscopy of blood smears was used for rapid diagnosis of infection in the bloodstream. BSI was diagnosed in 183 (48.0%) out of 382 out-of-hospital patients. The etiology of CBSIs was studied on 297 isolated strains of microorganisms. CBSIs rather often complicated the underlying disease in women and young people. The spectrum of CBSI pathogens included aerobic and anaerobic bacteria and fungi. Gram-positive cocci with the leadership of S.epidermidis (25.7%) were more often isolated among bacteria. 70% of all isolated pathogens grew under anaerobic conditions. CBSIs were characterized by polymicrobiality (33.5%) of two to four different microorganisms in one blood culture; the species of associates of polymicrobial blood cultures are shown. Microscopic examination of blood smears revealed microorganisms in 97.1% of cases, including associations of bacteria with fungi (66.9%). CBSIs occurred after contour plastic, in diseases of the respiratory system, genitourinary system, oral cavity, skin and subcutaneous tissue. Microbiological examination of the buffy coat is an alternative microbiological method of CBSIs diagnosis, which includes microscopy and blood cultivating and has a high diagnostic efficiency (97.1% and 48% respectively). It can become an option for replacing imported blood culture automated systems.

Clinical Impact of Accelerate Pheno Rapid Blood Culture Detection System in Bacteremic Patients.

BACKGROUND: Accelerate Pheno blood culture detection system (AXDX) provides rapid identification and antimicrobial susceptibility testing results. Limited data exist regarding its clinical impact. Other rapid platforms coupled with antimicrobial stewardship program (ASP) real-time notification (RTN) have shown improved length of stay (LOS) in bacteremia. METHODS: A single-center, quasi-experimental study of bacteremic inpatients before and after AXDX implementation was conducted comparing clinical outcomes from 1 historical and 2 intervention cohorts (AXDX and AXDX + RTN). RESULTS: Of 830 bacteremic episodes, 188 of 245 (77%) historical and 308 (155 AXDX, 153 AXDX + RTN) of 585 (65%) intervention episodes were included. Median LOS was shorter with AXDX (6.3 days) and AXDX + RTN (6.7 days) compared to historical (8.1 days) (P = .001). In the AXDX and AXDX + RTN cohorts, achievement of optimal therapy (AOT) was more frequent (93.6% and 95.4%, respectively) and median time to optimal therapy (TTOT) was faster (1.3 days and 1.4 days, respectively) compared to historical (84.6%, P ≤ .001 and 2.4 days, P ≤ .001, respectively). Median antimicrobial days of therapy (DOT) was shorter in both intervention arms compared to historical (6 days each vs 7 days; P = .011). Median LOS benefit during intervention was most pronounced in coagulase-negative Staphylococcus bacteremia (P = .003). CONCLUSIONS: LOS, AOT, TTOT, and total DOT significantly improved after AXDX implementation. Addition of RTN did not show further improvement over AXDX and an already active ASP. These results suggest that AXDX can be integrated into healthcare systems with an active ASP even without the resources to include RTN.

Real-World Evaluation of the Impact of Implementation of the Virtuo Blood Culture System in a Tertiary Care Hospital.

The bioMérieux BacT/Alert Virtuo blood culture system used in combination with resin-containing media may enhance the growth of microorganisms. Our objective was to assess the impact of transitioning to the Virtuo system in comparison to the VersaTREK blood culture system at a tertiary care medical center. We retrospectively reviewed all blood cultures performed at a 1,250-bed academic medical center between January and December 2018 (VersaTREK) and January and December 2019 (Virtuo). Blood culture positivity rates and contamination rates were compared before and after Virtuo implementation. Of 101,438 blood cultures performed during the study period, 48,839 (48.1%) were processed preimplementation and 52,599 (51.9%) postimplementation. The blood culture positivity rate increased from 8.1% preimplementation to 11.7% postimplementation (P < 0.001). Staphylococcus aureus was the most frequently isolated species in both time periods and had a higher recovery rate postimplementation (1.5% of all blood cultures obtained preimplementation versus 3.4% postimplementation; P < 0.001). A higher recovery rate in the postimplementation period was also noted for coagulase-negative staphylococci (1.9% preimplementation versus 2.7% postimplementation; P < 0.001), as well as modest but statistically significant changes for Escherichia coli (0.8% versus 1.0%; P < 0.001), Klebsiella pneumoniae (0.4% versus 0.5%; P = 0.005), and Candida albicans. (0.1% versus 0.2%; P = 0.038). The inpatient blood culture contamination rate was higher postimplementation (1.5% preimplementation versus 1.9% postimplementation; P < 0.001). The Virtuo blood culture system was associated with a higher observed proportion of positive blood cultures than the VersaTREK system. Future studies are needed to assess whether an increased rate of positive blood cultures is associated with changes in clinical outcomes.

B and T cell epitope-based peptides predicted from clumping factor protein of Staphylococcus aureus as vaccine targets.

Staphylococcus aureus infection is emerging as a global threat because of the highly debilitating nature of the associated disease's unprecedented magnitude of its spread and growing global resistance to antimicrobial medicines. Recently WHO has categorized these bacteria under the high global priority pathogen list and is one of the six nosocomial pathogens termed as ESKAPE pathogens which have emerged as a serious threat to public health worldwide. The development of a specific vaccine can stimulate an optimal antibody response, thus providing immunity against it. Therefore, in the present study efforts have been made to identify potential vaccine candidates from the Clumping factor surface proteins (ClfA and ClfB) of S. aureus. Employing the immunoinformatics approach, fourteen antigenic peptides including T-cell, B-cell epitopes were identified which were non-toxic, non-allergenic, high antigenicity, strong binding efficiency with commonly occurring MHC alleles. Consequently, a multi-epitope vaccine chimera was designed by connecting these epitopes with suitable linkers an adjuvant to enhance immunogenicity. Further, homology modeling and molecular docking were performed to construct the three-dimensional structure of the vaccine and study the interaction between the modeled structure and immune receptor (TLR-2) present on lymphocyte cells. Consequently, molecular dynamics simulation for 100 ns period confirmed the stability of the interaction and reliability of the structure for further analysis. Finally, codon optimization and in silico cloning were employed to ensure the successful expression of the vaccine candidate. As the targeted protein is highly antigenic and conserved, hence the designed novel vaccine construct holds potential against emerging multi-drug-resistant organisms.

Can the Xpert MRSA/SA BC assay be used as an antimicrobial stewardship tool? A prospective assay validation and descriptive impact assessment study in a South African setting.

BACKGROUND: Positive blood cultures showing Gram positive cocci in clusters signifies either Staphylococcus aureus or the less-virulent coagulase-negative staphylococci. Rapid identification and methicillin susceptibility determination with the Xpert MRSA/SA BC assay can improve management of S. aureus bloodstream infection and reduce inappropriate antibiotic use. METHODS: We prospectively evaluated the Xpert MRSA/SA BC assay in comparison with culture, on samples referred to our laboratory in the Western Cape, South Africa. We interviewed attending clinicians upon culture result availability, to assess antibiotic choices and estimate potential impact of the assay. RESULTS: Of the 231 samples included, there was 100% concordance between the Xpert MRSA/SA BC assay and culture (methicillin-resistant S. aureus 15/15, methicillin-susceptible S. aureus 42/42, coagulase-negative staphylococci 170/170). Time to final result could be reduced by approximately 30 h with the assay. Of the 178 patients with adequate antibiotic history, optimisation of antistaphylococcal therapy could have occurred more than 1 day sooner in 68.9% with S. aureus bloodstream infection (31/45, 95% CI 53.2-81.4%). Six of the 11 patients with methicillin-resistant S. aureus bloodstream infection (54.5%) could have received anti-MRSA cover sooner. Fifty-four days of antibiotic therapy could have been spared, equating to 0.3 days (95% CI, 0.2-0.4) saved per patient, driven by broad-spectrum beta-lactams (32 days, in 18.0% of the cohort). CONCLUSION: This assay has potential as an antimicrobial stewardship tool; costing and impact on clinical outcome in patients with S. aureus bloodstream infection should be assessed.

Toxic shock syndrome with a cytokine storm caused by Staphylococcus simulans: a case report.

BACKGROUND: Exotoxins secreted from Staphylococcus aureus or Streptococcus pyogenes act as superantigens that induce systemic release of inflammatory cytokines and are a common cause of toxic shock syndrome (TSS). However, little is known about TSS caused by coagulase-negative staphylococci (CoNS) and the underlying mechanisms. Here, we present a rare case of TSS caused by Staphylococcus simulans (S. simulans). CASE PRESENTATION: We report the case of a 75-year-old woman who developed pneumococcal pneumonia and bacteremia from S. simulans following an influenza infection. The patient met the clinical criteria for probable TSS, and her symptoms included fever of 39.5 °C, diffuse macular erythroderma, conjunctival congestion, vomiting, diarrhea, liver dysfunction, and disorientation. Therefore, the following treatment was initiated for bacterial pneumonia complicating influenza A with suspected TSS: meropenem (1 g every 8 h), vancomycin (1 g every 12 h), and clindamycin (600 mg every 8 h). Blood cultures taken on the day after admission were positive for CoNS, whereas sputum and pharyngeal cultures grew Streptococcus pneumoniae (Geckler group 4) and methicillin-sensitive S. aureus, respectively. However, exotoxins thought to cause TSS, such as TSS toxin-1 and various enterotoxins, were not detected. The patient's therapy was switched to cefazolin (2 g every 8 h) and clindamycin (600 mg every 8 h) for 14 days based on microbiologic test results. She developed desquamation of the fingers on hospital day 8 and was diagnosed with TSS. Conventional exotoxins, such as TSST-1, and S. aureus enterotoxins were not detected in culture samples. The serum levels of inflammatory cytokines, such as neopterin and IL-6, were high. CD8+ T cells were activated in peripheral blood. Vß2+ population activation, which is characteristic for TSST-1, was not observed in the Vß usage of CD8+ T cells in T cell receptor Vß repertoire distribution analysis. CONCLUSIONS: We present a case of S. simulans-induced TSS. Taken together, we speculate that no specific exotoxins are involved in the induction of TSS in this patient. A likely mechanism is uncontrolled cytokine release (i.e., cytokine storm) induced by non-specific immune reactions against CoNS proliferation.

Molecular Detection of Virulence Associated Genes in Coagulase Negative Staphylococci Isolated from Blood Culture.

BACKGROUND: Coagulase-negative staphylococci (CoNS) are one of the most important causes of infections. Unlike Staphylococcus aureus, less is known about their pathogenic mechanisms. In the present study, we aimed to evaluate the presence of virulence genes among 98 CoNS isolated from blood cultures of inpatients. METHODS: The isolates were identified by MALDI-TOF MS (Bruker Daltonics, Bremen, Germany). PCR was performed to detect 29 virulence factors using specific primers for icaA, icaB, icaC, icaD, icaADB, aap, fbe, aae, sesI, atIE, hla, hlb, hld, gehC, gehD, sea, seb, sec, sed, see, seg, seh, sei, tst, eta, etb, etd, etx, and pvl genes. The VITEK2 system (bio-Merieux, France) and the BD Phoenix™ System (Becton Dickinson, USA) were used for antimicrobial susceptibility testing. RESULTS: Staphylococcus epidermidis was found to be the most virulent CoNS species. All isolates were negative for eta, etb, etd, sea, seb, sed, see, seg, sei, and pvl virulence genes. We detected up to 15 virulence genes in a single isolate. The most common gene was icaC (73.5%), followed by icaA (57.1%), icaD (56.1%), aap (55.1%), aae (52.0%), sesl (51.0%), gehC (50.0%), hld (50.0%), hlb (49.0%), fbe (44.9%), atIE (37.8%), icaADB (37.8%), gehD (34.7%), icaB (31.6%), hla (30.6%), etx (2.0%), sec (1.0%), seh (1.0%), and tst (1.0%). CONCLUSIONS: We determined high rates of genes encoding biofilm formation. Only four isolates did not possess either the ica operon or aap gene. Although we found low rates of toxin-related genes, our data indicates that apart from biofilm formation, the CoNS isolates could express various virulence genes similar to those of Staphylococcus aureus.

Neonatal Sepsis: A Review of Pathophysiology and Current Management Strategies.

BACKGROUND: Early-onset sepsis, occurring within 72 hours of birth, and late-onset sepsis, occurring after this time period, present serious risks for neonates. While culture-based screening and intrapartum antibiotics have decreased the number of early-onset cases, sepsis remains a top cause of neonatal morbidity and mortality in the United States. PURPOSE: To provide a review of neonatal sepsis by identifying its associated risk factors and most common causative pathogens, reviewing features of the term and preterm neonatal immune systems that increase vulnerability to infection, describing previous and the most current management recommendations, and discussing relevant implications for the neonatal nurse and novice neonatal nurse practitioner. METHODS/SEARCH STRATEGY: An integrative review of literature was conducted using key words in CINAHL, Google Scholar, and PubMed. FINDINGS/RESULTS: Group B streptococcus and Escherichia coli are the most common pathogens in early-onset sepsis, while Coagulase-negative staphylococci comprise the majority of cases in late-onset. The neonatal immune system is vulnerable due to characteristics including decreased cellular activity, underdeveloped complement systems, preferential anti-inflammatory responses, and insufficient pathogenic memory. Blood cultures remain the criterion standard of diagnosis, with several other adjunct tests under investigation for clinical use. The recent development of the sepsis calculator has been a useful tool in the management of early-onset cases. IMPLICATIONS FOR PRACTICE: It is vital to understand the mechanisms behind the neonate's elevated risk for infection and to implement evidence-based management. IMPLICATIONS FOR RESEARCH: Research needs exist for diagnostic methods that deliver timely and sensitive results. A tool similar to the sepsis calculator does not exist for preterm infants or late-onset sepsis, groups for which antibiotic stewardship is not as well practiced.Video Abstract available athttps://journals.lww.com/advancesinneonatalcare/Pages/videogallery.aspx?autoPlay=false&videoId=40.

Utility of Blood Cultures and Empiric Antibiotics in Febrile Pediatric Hemophilia Patients With Central Venous Access Devices.

BACKGROUND: Children with hemophilia frequently require long-term central venous access devices (CVADs) for regular infusion of factor products. Hemophilia patients are not immunocompromised, but the presence and use of CVADs are associated with infections including bacteremia. Currently, the utility of blood cultures in evaluation of the febrile hemophilia patient with an indwelling CVAD is unknown, nor is optimal empiric antibiotic use. METHODS: We performed a retrospective cross-sectional study of febrile immunocompetent hemophilia patients with CVADs presenting to a large academic urban pediatric emergency department from 1995 to 2017. We used a natural language processing electronic search, followed by manual chart review to construct the cohort. We analyzed rate of pathogen recovery from cultures of blood in subgroups of hemophilia patients, the pathogen profile, and the reported pathogen susceptibilities to ceftriaxone. RESULTS: Natural language processing electronic search identified 181 visits for fever among hemophilia patients with indwelling CVADs of which 147 cases from 44 unique patients met study criteria. Cultures of blood were positive in 56 (38%) of 147 patients (95% confidence interval, 30%-47%). Seventeen different organisms were isolated (10 pathogens and 7 possible pathogens) with Staphylococcus aureus and coagulase-negative Staphylococcus species as the most common. Thirty-four percent of isolates were reported as susceptible to ceftriaxone. Positive blood cultures were more common in cases involving patients with inhibitors (n = 71) versus those without (n = 76), odds ratio, 7.4 (95% confidence interval, 3.5-15.9). This was observed irrespective of hemophilia type. CONCLUSIONS: Febrile immunocompetent hemophilia patients with indwelling CVADs have high rates of bacteremia. Empiric antimicrobial therapy should be targeted to anticipated pathogens and take into consideration local susceptibility patterns for Staphylococcus aureus.

Performance of PCR/Electrospray Ionization-Mass Spectrometry on Whole Blood for Detection of Bloodstream Microorganisms in Patients with Suspected Sepsis.

Blood culture (BC) often fails to detect bloodstream microorganisms in sepsis. However, molecular diagnostics hold great potential. The molecular method PCR/electrospray ionization-mass spectrometry (PCR/ESI-MS) can detect DNA from hundreds of different microorganisms in whole blood. The aim of the present study was to evaluate the performance of this method in a multicenter study including 16 teaching hospitals in the United States (n = 13) and Europe (n = 3). First, on testing of 2,754 contrived whole blood samples, with or without spiked microorganisms, PCR/ESI-MS produced 99.1% true-positive and 97.2% true-negative results. Second, among 1,460 patients with suspected sepsis (sepsis-2 definition), BC and PCR/ESI-MS on whole blood were positive in 14.6% and 25.6% of cases, respectively, with the following result combinations: BC positive and PCR/ESI-MS negative, 4.3%; BC positive and PCR/ESI-MS positive, 10.3%; BC negative and PCR/ESI-MS positive, 15.3%; and BC negative and PCR/ESI-MS negative, 70.1%. Compared with BC, PCR/ESI-MS showed the following sensitivities (coagulase-negative staphylococci not included): Gram-positive bacteria, 58%; Gram-negative bacteria, 78%; and Candida species, 83%. The specificities were >94% for all individual species. Patients who had received prior antimicrobial medications (n = 603) had significantly higher PCR/ESI-MS positivity rates than patients without prior antimicrobial treatment-31% versus 22% (P < 0.0001)-with pronounced differences for Gram-negative bacteria and Candida species. In conclusion, PCR/ESI-MS showed excellent performance on contrived samples. On clinical samples, it showed high specificities, moderately high sensitivities for Gram-negative bacteria and Candida species, and elevated positivity rates during antimicrobial treatment. These promising results encourage further development of molecular diagnostics to be used with whole blood for detection of bloodstream microorganisms in sepsis.

Molecular characteristics and predictors of mortality among Gram-positive bacteria isolated from bloodstream infections in critically ill patients during a 5-year period (2012-2016).

To identify the molecular characteristics of Gram-positive cocci isolated from blood cultures and clinical outcome among critically ill patients. This retrospective study was conducted in the general intensive care unit of the University General Hospital of Patras, Greece, during a 5-year period (2012-2016). All adult patients with a Gram-positive BSI were included. PCR was applied to identify mecA gene (staphylococci); vanA, vanB, and vanC genes (enterococci). Linezolid-resistant S. epidermidis, MRSA, and VRE were further typed by multilocus sequence typing. Mutations in region V of 23S rDNA and ribosomal protein L4were investigated by PCR and sequencing analysis. The presence of the cfr gene was tested by PCR. In total, 141 Gram-positive BSIs were included. Coagulase-negative staphylococci predominated (n = 69; 65 methicillin-resistant, 23 linezolid-resistant carrying both C2534T and T2504A mutations and belonging to the ST22 clone), followed by enterococci (n = 46; 11 vancomycin-resistant carrying vanA gene, classified into four clones), S. aureus (n = 22; 10 methicillin-resistant, classified into three clones) and streptococci (n = 4). The most common type of infection was catheter-related (66; 46.8%), followed by primary BSI (28; 19.9%). Overall 14-day fatality was 24.8%. Multivariate analysis revealed septic shock as independent predictor of fatality, while appropriate empiric antimicrobial treatment and catheter-related BSI were identified as a predictor of good prognosis. Even though most of Gram-positive cocci were multidrug-resistant, fatality rate was low, associated with catheter-related BSIs. Among CNS, LR isolates represented one-third of BSIs due to the dissemination of ST22 S. epidermidis propagated by utilization of linezolid.

Performance of the Hologic Panther Fusion® MRSA Assay for the nasal screening of methicillin-sensitive and methicillin-resistant Staphylococcus aureus carriage.

Staphylococcus aureus (SA) nasal carriage screening is usually based on either culture or molecular biology. The aim of the study was to evaluate the performance of the Panther Fusion® MRSA Assay (PF) that proposes a complete automation of the molecular screening for MSSA and MRSA carriage. Four hundred thirty-four nasal samples collected on ESwab™ were screened using PF. Results were compared with standard culture on BBL™ CHROMagar™ Staph aureus and chromID® MRSA agar. Discordant results were analyzed with additional techniques: Xpert SA Nasal Complete on GeneXpert (GX), culture on selective agar after 24 h in broth enrichment, and, if necessary, characterization of mec gene and SCCmec cassette using DNA microarray. The PF presented an overall agreement of 97.5% for SA detection and 97.9% for MRSA detection. Furthermore, 7.1% (31/434) of the samples were SA-negative in primary culture but SA-positive using PF and GX, confirming the greater sensitivity of molecular tests compared with culture. Of note, 4 out of 30 MRSA-positive samples were not detected due to an atypical SCCmec cassette, while 2 samples were falsely detected as MRSA due to co-colonization with a MSSA drop-out strain and a methicillin-resistant coagulase-negative staphylococcal strain. Considering all results, the PF instrument appears as a reliable and rapid (< 3 h) package for MSSA/MRSA nasal screening. This technology using random access capability and direct sampling of the primary container is innovative and corresponds therefore to a new step in complete molecular biology automation in bacteriology.