Pre-engraftment bacteremia after allogeneic hematopoietic cell transplantation without primary fluoroquinolone antibacterial prophylaxis.

BACKGROUND: Bacteremia is a common complication in allogeneic hematopoietic cell transplant recipients (alloHCTr), especially during the pre-engraftment period. International guidelines recommend antibacterial prophylaxis (ABP), despite potential selection for multidrug-resistant organisms (MDRO). Limited contemporary data exist on the epidemiology of pre-engraftment bacteremia in alloHCTr, who do not receive ABP. METHODS: We performed a retrospective observational single-center cohort study including all consecutive adult alloHCTr (2015-2021), investigating the incidence, risk factors, and outcomes of bacteremia during the engraftment period. Primary fluoroquinolone (FQ) ABP is not routinely administered in our center. RESULTS: Among 421 patients identified, 124 bacteremia episodes were observed in 121/421 (29%) alloHCTr. The median time to the 1st bacteremia episode was 9 days (IQR 6-11). Most (105/124, 85%) episodes were monomicrobial, while >1 pathogens were identified in 19/124 (15%) episodes. Overall, 152 pathogens were isolated, with a predominance of Gram-positive (118/152, 78%), including coagulase-negative staphylococci (n:47), streptococci (n:46), and enterococci (n:15), followed by Gram-negative bacteria (GNB, 30/152, 20%), and anaerobes (4/152, 3%). There were 2/152 (1%) MDRO (extended-spectrum beta-lactamase producing) GNB. Multivariable analyses identified age >40-year-old (OR 2.4, P = 0.02), male gender (OR 1.8, P = 0.02), and a haploidentical/mismatched unrelated donor (OR 2.5, P < 0.001) as independent risk factors for bacteremia. All cause 30-day mortality among alloHCTr with bacteremia was 0.8% (1/121): one patient died due to an HCT-related complication. CONCLUSION: Despite lack of primary FQ ABP, low rates of bacteremia were observed during the pre-engraftment period, with low MDRO prevalence and mortality. Our findings may allow to revisit the need for primary universal FQ ABP in high-risk neutropenic hematology patients.

Bacterial infections in solid organ transplant recipients.

PURPOSE OF REVIEW: Bacteria are the leading cause of infections in solid organ transplant (SOT) recipients, significantly impacting patient outcome. Recently detailed and comprehensive epidemiological data have been published. RECENT FINDING: This literature review aims to provide an overview of bacterial infections affecting different types of SOT recipients, emphasizing underlying risk factors and pathophysiological mechanisms. SUMMARY: Lung transplantation connects two microbiotas: one derived from the donor's lower respiratory tract with one from the recipient's upper respiratory tract. Similarly, liver transplantation involves a connection to the digestive tract and its microbiota through the bile ducts. For heart transplant recipients, specific factors are related to the management strategies for end-stage heart failure based with different circulatory support tools. Kidney and kidney-pancreas transplant recipients commonly experience asymptomatic bacteriuria, but recent studies have suggested the absence of benefice of routine treatment. Bloodstream infections (BSI) are frequent and affect all SOT recipients. Nonorgan-related risk factors as age, comorbidity index score, and leukopenia contribute to BSI development. Bacterial opportunistic infections have become rare in the presence of efficient prophylaxis. Understanding the epidemiology, risk factors, and pathophysiology of bacterial infections in SOT recipients is crucial for effective management and improved patient outcomes.

MPox virus: an unusual aetiology of peritonitis.

We describe a rare case of severe disseminated monkeypox (MPox) virus infection complicated by peritonitis in a 44-year-old man living with well-controlled HIV. The patient was successfully treated with tecovirimat without requiring surgery. MPox should be considered in the differential diagnosis of non-bacterial peritonitis in patients at risk of infection.

Accurate Detection of SARS-CoV-2 by Next-Generation Sequencing in Low Viral Load Specimens.

As new SARS-CoV-2 variants emerge, there is an urgent need to increase the efficiency and availability of viral genome sequencing, notably to detect the lineage in samples with a low viral load. SARS-CoV-2 genome next-generation sequencing (NGS) was performed retrospectively in a single center on 175 positive samples from individuals. An automated workflow used the Ion AmpliSeq SARS-CoV-2 Insight Research Assay on the Genexus Sequencer. All samples were collected in the metropolitan area of the city of Nice (France) over a period of 32 weeks (from 19 July 2021 to 11 February 2022). In total, 76% of cases were identified with a low viral load (Ct ≥ 32, and ≤200 copies/µL). The NGS analysis was successful in 91% of cases, among which 57% of cases harbored the Delta variant, and 34% the Omicron BA.1.1 variant. Only 9% of cases had unreadable sequences. There was no significant difference in the viral load in patients infected with the Omicron variant compared to the Delta variant (Ct values, p = 0.0507; copy number, p = 0.252). We show that the NGS analysis of the SARS-CoV-2 genome provides reliable detection of the Delta and Omicron SARS-CoV-2 variants in low viral load samples.

Management of prosthetic joint infections in France: a national audit to identify key situations requiring innovation and homogenization.

BACKGROUND: Prosthetic joint infections (PJI) are one of the most serious complication of arthroplasty. The management of PJI needs a multidisciplinary collaboration between orthopaedic surgeon, infectious disease specialist and microbiologist. In France, the management of PJI is organized around reference centres (CRIOACs). Our main objective was to perform an audit through a questionnaire survey based on clinical cases, to evaluate how French physicians manage PJI. Eligible participants were all physicians involved in care of patients presenting a PJI. Physicians could answer individually, or collectively during a multidisciplinary team meeting dedicated to PJI. The survey consisted as three questionnaires organized in a total of six clinical cases. RESULTS: Answers from the CRIOACs to the three questionnaires were 92, 77, and 53%. Between 32 and 39% of respondents did not administer antibiotic prophylaxis despite positive S. aureus pre-operative documentation. One-stage exchange strategy was widely preferred in all clinical cases, with no difference between CRIOACs and other centres. Rifampicin was prescribed for S. aureus PJI, in a situation with (90-92%) or without any prosthesis (70%). There was no consensus for the total antibiotic regimen duration, with prescriptions from six to 12 weeks for a majority of respondents. CONCLUSIONS: Surgical strategy for the management of PJI was homogenous with a preference for a one-stage exchange strategy. Medical management was more heterogenous, which reflects the heterogeneity of those infections and difficulties to perform studies with strong conclusions.

A Population Pharmacokinetic Analysis of Continuous Infusion of Cloxacillin during Staphylococcus aureus Bone and Joint Infections.

Intravenous administration of antibiotics is recommended during the early phase of methicillin-susceptible S. aureus (MSSA) bone and joint infection (BJI). We sought to compare the plasma concentrations of cloxacillin administered alternately by continuous and intermittent infusion (CI and ItI) in patients with MSSA BJI. In this prospective crossover trial, patients were randomly assigned to receive either 3 days of CI (two 75-mg/kg 12-h cloxacillin infusions per day) and then 3 days of ItI (four 37.5-mg/kg 1-h cloxacillin infusions per day) or vice versa. The drug concentration measurement was performed on day 3 of each type of administration at 1, 6, and 11 h and at 1, 2, 3, 4, and 6 h after the beginning of CI and ItI, respectively. We used the nonparametric algorithm NPAG to estimate population pharmacokinetic (PK) parameters. The final model was used to perform pharmacokinetic/pharmacodynamic (PK/PD) simulations and calculate the probabilities of target attainment (PTA) for several ItI and CI dosing regimens. We considered two PK/PD targets of time spent above the MIC for free cloxacillin concentrations (fT>MIC): 50 and 100%. Eighty-four concentrations from 11 patients were analyzed. A two-compartment model adequately described the data. ItI with q6h regimens and short 1-h infusions of 2,000 or 3,000 mg were associated with low PTA, even for the low target (50% fT>MIC) while 3-h infusions and continuous infusions (6 to 12 g/day) were associated with a PTA of >90% for an MIC up to 0.5 mg/liter. These results support the use of prolonged or continuous infusion of cloxacillin in patients with BJI.

Amoxicillin/clavulanic acid+aminoglycoside as empirical antibiotic treatment in severe community-acquired infections with diagnostic uncertainty.

Diagnostic uncertainty is common in the emergency room and multidrug-resistant bacteria emerge in the community setting, implying to establish the most efficient empirical antibiotic therapy (eEAT). Our aim was to identify such eEAT, considering that in case of DU with severe clinical presentation, most prescribers would propose an empiric combination (EC). The medical dashboard of our ward records prospectively 28 characteristics of each hospitalization including hospitalization motive, final diagnosis, and all antibiotics prescribed. All patients with community-acquired bacteremia (CAB) were included. DU was defined by a discrepancy between suspected diagnosis in the emergency room and final diagnosis. eEAT was defined by in vitro activity of at least one prescribed compound. Finally, independently from the dashboard, we retrospectively compared 2 CTs: amoxicillin/clavulanic acid (AMC)+gentamicin (G) and cefotaxime (3GC)+G. One thousand thirty-four patients with a final diagnosis of CAB were identified from July 2005 to June 2018, including 357 DU (35%) at baseline. eEAT (n = 553) was associated with a trend towards a lower death rate compared to inefficient therapies: 5.4 vs 10.0% (p = 0.053), and effective antibiotic reassessment was the most protective factor against an unfavorable outcome: 0.34 (0.16-0.71). Bacteria involved in case of UD were resistant to AMC+G and to 3GC+G in 8.1% and 12.8% of patients, respectively. Diagnostic uncertainty was a frequent event requiring antibiotic reassessment. As the latter was not systematically realized, the best eEAT is required and AMC+aminoglycoside should be considered.

Adherence to antibiotic guidelines for erysipelas or cellulitis is associated with a favorable outcome.

Outside areas of S. aureus strains resistant to methicillin (MRSA) in the community, no studies showed a relationship between the treatment for erysipelas or cellulitis and the outcome. We aimed to measure the impact of an internal therapeutic protocol, based on national guidelines on patients' outcome. This study was based on the dashboard of the infectious diseases department, which prospectively includes 28 parameters for all admitted patients. We included community-acquired erysipelas and cellulitis; exclusion criteria were abscesses at admission; ear, nose, throat, or dental cellulitis; pyomyositis; and length of stay ≤ 2 days. Adherence to guidelines was defined by the use of amoxicillin, amoxicillin/clavulanic acid, clindamycin, or pristinamycin, alone or in combination or successively. A poor outcome was defined by surgical procedure or intensive care requirement or death occurring after 5 days or more of antibiotic therapy. From July 2005 to June 2017, 630 cases of erysipelas or cellulitis were included. Blood cultures performed in 567 patients (90%) were positive in 39 cases (6.9%). Adherence rate to guidelines was 65% (410 cases). A poor outcome was recorded in 54 (8.5%) patients, less frequently in case of adherence to guidelines: 26/410 (6.3%) vs 28/220 (12.7%), p = 0.007. In logistic regression analysis, two risk factors were associated with a poor outcome: peripheral arterial disease, AOR 4.80 (2.20-10.49); and bacteremia, AOR 5.21 (2.31-11.76), while guideline adherence was the only modifiable protective factor, OR 0.48 (0.26-0.89). In erysipelas and cellulitis, adherence to guidelines was associated with a favorable outcome.

Managing ESBL-producing Enterobacteriaceae-related urinary tract infection in primary care: a tool kit for general practitioners.

In Southern France, approximately 4% of E. coli isolates from community-acquired urinary tract infections are extended spectrum beta-lactamase producers, while carriage rates for enterobacteriaceae (ESBL-E) range from 3 to 6%. General practitioners (GP) are unfamiliar with the management of patients harboring ESBL-E. Providing them with a specific tool kit should assist in their therapeutic approach and optimize antimicrobial prescription an ESBL-E tool kit was developed by a multidisciplinary team: infectious diseases (ID) specialists, microbiologists, pharmacologists, and nursing home staff. This tool kit includes treatment protocols, GP and patient information leaflets, a list of infection control measures, and contact details of ID physicians for specialized advice. A community-based (including nursing homes) prospective study was conducted in 2012 in Southeastern France to test the tool kit in the context of ESBL-E-related urinary tract infections (UTI). ESBL-E-related UTI were identified in 88 patients, 66 GPs were contacted by the microbiology laboratory, 56 stated they were offered the tool kit, 48 said they had received it, and 41 stated they had read its contents. Use of the tool kit was significantly correlated with appropriate antibiotic prescription, which concerned 36/39 tool kit users versus 13/20 non-users (p = 0.0125) and 40 GPs expressed an average satisfaction rate of 4.2 on a scale of 0 to 5. Availability of a specific tool for managing patients harboring ESBL-E, now completed with a website, can assist community-based GPs and improve antimicrobial prescription.

Patients with community-acquired bacteremia of unknown origin: clinical characteristics and usefulness of microbiological results for therapeutic issues: a single-center cohort study.

Bacteremia of unknown origin (BUO) are associated with increased mortality compared to those with identified sources. Microbiological data of those patients could help to characterize an appropriate empirical antibiotic treatment before bloodcultures results are available during sepsis of unknown origin. Based on the dashboard of our ward that prospectively records several parameters from each hospitalization, we report 101 community-acquired BUO selected among 1989 bacteremic patients from July 2005 to April 2016, BUO being defined by the absence of clinical and paraclinical infectious focus and no other microbiological samples retrieving the bacteria isolated from blood cultures. The in-hospital mortality rate was 9%. We retrospectively tested two antibiotic associations: amoxicillin-clavulanic acid + gentamicin (AMC/GM) and 3rd generation cephalosporin + gentamicin (3GC/GM) considered as active if the causative bacteria was susceptible to at least one of the two drugs. The mean age was 71 years with 67% of male, 31 (31%) were immunocompromised and 52 (51%) had severe sepsis. Eleven patients had polymicrobial infections. The leading bacterial species involved were Escherichia coli 25/115 (22%), group D Streptococci 12/115 (10%), viridans Streptococci 12/115 (10%) and Staphylococcus aureus 11/115 (9%). AMC/GM displayed a higher rate of effectiveness compared to 3GC/GM: 100/101 (99%) vs 94/101 (93%) (p = 0.04): one Enterococcus faecium strain impaired the first association, Bacteroides spp. and Enterococcus spp. the second. In case of community-acquired sepsis of unknown origin, AMC + GM should be considered.

Clinical Aspects of Syphilis Reinfection in HIV-Infected Patients.

BACKGROUND: The incidence of HIV-syphilis co-infection has risen since 2000, especially among men having sex with men (MSM). Syphilis reinfection can occur, but the clinical features of such events remain poorly characterized. OBJECTIVE: To compare the cutaneous lesions seen with syphilis reinfections with those of first episodes in HIV-infected patients. METHODS: In a cohort of HIV-infected patients, syphilis reinfection was established both clinically and biologically by evaluating changes in Venereal Disease Research Laboratory titers. Photographs and medical records were studied in order to determine the type of skin lesions and their quantification. RESULTS: Among 533 HIV-infected patients, 42 (8%) experienced a first syphilis infection. Thirteen episodes of reinfection occurred in 12/42 (28%) patients, all MSM. In 78% of cases, reinfections were less symptomatic than first episodes. All patients presented classical syphilis lesions. CONCLUSIONS: We observed a high rate of reinfection, but with less severe skin manifestations during reinfection episodes.

What Place Is There for Long-Acting Antibiotics in the Management of Gram-Positive Infections? A Qualitative Cross-Sectional Study.

OBJECTIVES: To identify the current practices with long half-life lipoglycopeptides (LGPs) and potential use/position of oritavancin. RESULTS: Despite their indication being limited to skin and soft tissue infections (SSTIs), long half-life lipoglycopeptides are mainly used off-label to treat bone and joint infections (BJIs) and infective endocarditis. Oritavancin and dalbavancin are both semisynthetic lipoglycopeptide antibiotics with activity against Gram-positive organisms. The game-changing property of these two antibiotics is their one-time dosing. Due to its shorter half-life, oritavancin might have an advantage over dalbavancin for a treatment duration of less than 2 weeks, as it could be used both in prolonged treatments of complicated patients in BJIs or administered as a single-dose treatment for Gram-positive cocci infections usually treated by a 5- to 10-day antibiotic course. These infections include urinary tract infections, bacteremias, catheter-related infections, etc. In addition to the possibility of being used as an end-of-treatment injection, oritavancin could be used as an empiric therapy treatment in the postoperative period in the context of device-associated especially prosthetic joint infections to allow for the early discharge of the patient. METHODS: A qualitative survey was conducted in March 2022 including sixteen infectiologists, one internist, five hospital pharmacists, and one pharmacologist. CONCLUSION: Long half-life lipoglycopeptides contribute to changing the paradigm in the management of acute bacterial infections, as infectiologists now consider a range of indications and patient profiles for one single drug. Oritavancin strengthens the therapeutic arsenal in numerous infections from BJIs to urinary tract infections and could help to manage specific clinical situations, on top of providing potential benefits for the hospital's budget.

Efficacy of an antimicrobial stewardship intervention for early adaptation of antibiotic therapy in high-risk neutropenic patients.

BACKGROUND: The 4th European Conference on Infections in Leukemia recommends early adaptation of empirical antibiotic therapy (EAT) for febrile neutropenia in stable patients. OBJECTIVES: To assess the efficacy of an antimicrobial stewardship (AMS) intervention promoting early de-escalation and discontinuation of EAT in high-risk neutropenic patients. METHODS: This before-after study was conducted in the hematology department of the University Hospital of Nice, France. The AMS intervention included the development of clinical decision support algorithms, a twice-weekly face-to-face review of all antibiotic prescriptions and monthly feedback on the intervention. The primary endpoint was overall antibiotic consumption during hospital stay, expressed as days of therapy (DOT). RESULTS: A total of 113 admissions were included: 56 during the pre-intervention period and 57 during the intervention period. Induction chemotherapy and conditioning for allogeneic stem cell transplantation were the most frequent reasons for admission. In the intervention period, there was a significant decrease in overall antibiotic consumption (median DOT 20 vs. 28 days, p = 0.006), carbapenem consumption (median DOT 5.5 vs. 9 days, p = 0.017) and anti-resistant Gram-positive agents consumption (median DOT 8 vs. 11.5 days, p = 0.017). We found no statistical difference in the rates of intensive care unit admission (9% in each period) and 30-day mortality (5% vs. 0%, p = 0.243). Compliance with de-escalation and discontinuation strategies was significantly higher in the intervention period (77% vs. 8%, p < 0.001). CONCLUSION: A multifaceted AMS intervention led to high compliance with early de-escalation and discontinuation of EAT and lower overall antibiotic consumption, without negatively affecting clinical outcomes.

RAC2 gain-of-function variants causing inborn error of immunity drive NLRP3 inflammasome activation.

A growing number of patients presenting severe combined immunodeficiencies attributed to monoallelic RAC2 variants have been identified. The expression of the RHO GTPase RAC2 is restricted to the hematopoietic lineage. RAC2 variants have been described to cause immunodeficiencies associated with high frequency of infection, leukopenia, and autoinflammatory features. Here, we show that specific RAC2 activating mutations induce the NLRP3 inflammasome activation leading to the secretion of IL-1ß and IL-18 from macrophages. This activation depends on the activation state of the RAC2 variant and is mediated by the downstream kinase PAK1. Inhibiting the RAC2-PAK1-NLRP3 inflammasome pathway might be considered as a potential treatment for these patients.

Time-to-detection in culture of Mycobacterium tuberculosis: performance for assessing index cases contact-positivity.

OBJECTIVES: Time-to-detection (TTD) in culture on liquid media is inversely correlated to bacillary load and should be a contributing factor for assessing tuberculosis transmission. We wanted to assess if TTD was a better alternative than smear status to estimate transmission risk. METHODS: From October 2015 to June 2022, we retrospectively studied a cohort of index cases (IC) with pulmonary tuberculosis (tuberculosis disease [TD]) from which samples were culture-positive before treatment. We studied the correlation between TTD and contact-positivity (CP) of IC contacts: CP was defined as CP = 1 (CP group) in case of TD or latent tuberculosis infection (LTI) in at least one screened contact of an IC, and CP = 0 otherwise (contact-negativity [CN] group). Univariate and multivariable analyses (logistic regression) were done. RESULTS: Of the 185 IC, 122 were included, generating 846 contact cases of which 705 were assessed. A transmission event (LTI or TD) was identified in 193 contact cases (transmission rate: 27%). At day 9, 66% and 35% of the IC had their sample positive in culture for CP and CN groups, respectively. Age and TTD ≤9 days were independent criteria of CP (odds ratio 0.97, confidence interval [0.95-0.98], P = 0.002 and odds ratio 3.52, confidence interval [1.59-7.83], P = 0.001, respectively). CONCLUSION: TTD was a more discriminating parameter than smear status to evaluate the transmission risk of an IC with pulmonary tuberculosis. Therefore, TTD should be considered in the contact-screening strategy around an IC.

Effectiveness and safety of dalbavancin in France: a prospective, multicentre cohort study.

OBJECTIVES: Dalbavancin is a lipoglycopeptide antibiotic approved for the treatment of acute bacterial skin and skin structure infections. However, several studies have suggested that it is used mostly for off-label indications. We aimed to describe the use of dalbavancin in patients who received at least one dose of the antibiotic in France. METHODS: Prospective, observational, multicentre study conducted in France from September 2018 to April 2020. The primary outcome was the clinical response at 30 days after the last dalbavancin dose. RESULTS: A total of 151 patients in 16 centres were included in this study. The main infection sites were bone and joint infections (55.0%), multisite infections (15.9%), and vascular infections (14.6%), and the primary pathogens were coagulase-negative staphylococci (N = 82), Staphylococcus aureus (N = 51), and enterococci (N = 27). Most patients (71.5%) received three previous antibiotic treatments. The number of dalbavancin injections per patient was 1 in 26 patients (17.2%), 2 in 95 patients (62.9%), 3 in 17 patients (11.3%), and more than 3 in 13 patients (8.6%), with a mean cumulative dose of 3089 ± 1461 mg per patient. Among the 129 patients with a complete follow-up, clinical success was achieved in 119 patients (92.2%). At least 1 adverse event was reported in 67 patients (44.4%), including 12 (7.9%) patients with dalbavancin-related adverse events. CONCLUSIONS: The results of the study showed that dalbavancin is used mostly for off-label indications and in heavily pretreated patients in France. The clinical response at 30 days after the last dose was favourable in most patients, with a good safety profile.

Lesson from the COVID-19 pandemic lockdown: A major change of hospital-diagnosed bacteremia epidemiology.

OBJECTIVES: When the COVID-19 pandemic reached France early in 2020, the enforced nationwide lockdown deeply altered lifestyle as well as hospital processes and modalities of care. The aim of the study was to evaluate the impact during the lockdown of the first epidemic wave on the epidemiology of bacteremia in one French University Hospital. PATIENTS AND METHODS: Retrospective cohort study including adult patients with positive blood culture between 23rd March to 24th May 2020. The clinical-microbiological characteristics were compared with those of the period from 25th March to 26th May 2019. The data were adjusted to the number of hospitalizations (h). RESULTS: In 2020, 189 bacteremia were diagnosed from 1939 vials (9658 hospitalizations, 10911 emergency room consultations) compared to 143 from 1976 vials (14797 hospitalizations, 16493 emergency room consultations) recorded in 2019. The incidence of bacteremia increased up to 19.7 per 1000h in 2020 vs 9.7 in 2019 (p < 0.001). The main differences (2020 vs 2019) were: Staphylococcus aureus bacteremia (2.4 vs 1.0/1000h, p = 0.012), polymicrobial bacteremia (2.2 vs 0.9/1000h p = 0.013) and Gram-negative bacteremia (8.9 vs 4.3/1000h, p < 0.01). Conversely, Streptococcus pneumoniae incidence decreased (0 vs 0.47/1000h, p = 0.047). The standardized incidence ratio calculation confirmed these results. CONCLUSION: The lockdown and the impact of the first wave of the Covid-19 pandemic on the health system resulted in increased hospital-diagnosed bacteremia and decreased pneumococcal bacteremia. Disruption and overload of ICUs, lockdown with preventive control measures, and decrease in human-to-human interaction may have been the main reasons.

Hepatitis E Virus Infection Epidemiology in Recipients of Allogeneic Hematopoietic Cell Transplant.

Among 292 recipients of allogeneic hematopoietic cell transplant (2018-2022), 64 (21.9%) tested positive for anti-hepatitis E virus (HEV) immunoglobulin G. Among 208 recipients tested by plasma/serum HEV polymerase chain reaction (2012-2022), 3 (1.4%) primary HEV infections were diagnosed; in 1 patient, plasma HEV polymerase chain reaction relapsed positive for 100 days. HEV infection remains rare albeit associated with persistent viral replication.