Bacterial Bloodstream Infections Research Articles

Utility of Obtaining Follow-Up Blood Cultures in Gram-Negative Bacterial Bloodstream Infection Among Patients With Hematologic Malignancies.

There is an ongoing debate on the benefit of obtaining repeat blood cultures for Gram-negative bacterial bloodstream infections (GNBSI). However, there is a scarcity of data concerning patients with hematologic malignancies. We sought to assess the utility of obtaining follow-up blood cultures (FUBC) in GNBSI among patients with hematologic malignancies. A retrospective chart review was conducted to identify all admitted patients with hematologic malignancies with GNBSI from 2018 to 2021 at a tertiary academic medical center. We collected demographics, cancer history and treatment, microbiology and antibiotic use, and clinical course. Descriptive statistics were used. A total of 46 episodes of GNBSI among 38 patients were included. The median age was 61.5 years, 63% were male, 50% were White, and 16% were Latinx. Most patients had acute myeloid leukemia (60%), and the most common chemotherapy regimen was cytarabine or nelarabine regimens (35%).Klebsiella pneumoniaewas responsible for 37% of the GNBSI cases, in the setting of long-term central venous catheter use (65%) and gastrointestinal sources (50%). FUBCs were collected among almost all patients (98%). Only three cases (7%) had positive FUBC: one had a delay in appropriate therapy, another had a lack of source control, and the last case did not have a source identified. Most patients were treated with beta-lactams (52%) with duration 8-14 days (52%). 22% were admitted to ICU and 9% died during their hospitalization. We found a few cases of positive FUBC. Routine FUBC may not be appropriate for all GNBSI patients with hematological malignancies, particularly during the current blood culture bottle shortage.

Diversity, Distribution, and Resistance Profiles of Bacterial Bloodstream Infections in Three Tertiary Referral Hospitals in Rwanda Between 2020 and 2022.

Background: The burden of bacterial bloodstream infections (BSIs) is rapidly increasing in Africa including Rwanda. Methods: This is a retrospective study that investigates the diversity, distribution, and antimicrobial susceptibility profiles of BSI bacteria in three tertiary referral hospitals in Rwanda between 2020 and 2022. Results: A total of 1532 blood culture tests were performed for visiting patients. Overall, the proportions of Gram-negative and Gram-positive bacteria were 48.2% and 51.8, respectively. Staphylococcus aureus was the predominant species accounting for 25% of all Gram-positive BSI species, and Klebsiella species represented 41% of all Gram-negative BSI species. Antimicrobial susceptibility testing revealed that Amikacin exhibited the highest activity against Enterobacter spp., Serratia spp., and Escherichia coli in >92% of cases and Klebsiella spp. in 75.7%. Meropenem and Imipenem were highly efficacious to Salmonella spp. (100% susceptibility), Enterobacter spp. (96.2% and 91.7%, respectively), and Escherichia coli (94.7% and 95.5%, respectively). The susceptibility of Enterococcus spp., S. aureus, and Streptococcus spp. to Vancomycin was 100%, 99.5%, and 97.1%, respectively. Klebsiella spp. was highly sensitive to Colistin (98.7%), Polymyxin B (85.6%), Imipenem (84.9%), and Meropenem (78.5%). Conclusions: We recommend strengthening the implementation of integrated transdisciplinary and multisectoral One Health including AMR stewardship for the surveillance, prevention, and control of AMR in Rwanda.

Bacteriological Profile and Antibiotic Susceptibility Pattern of Isolates from Suspected Neonatal Septicemia Patients in Different Hospitals of Chattogram

Background: Bacterial blood stream infection is an important cause of morbidity and mortality in neonates. This study was undertaken to identify the bacterial isolates from suspected neonatal septicemia patients and to understand their antimicrobial susceptibility pattern in Chattogram. Materials and methods: A cross-sectional descriptive type of study was done for a period of two years from January 2022 to December 2023. Blood samples from 340 neonates with clinically suspected septicemia were taken for automated culture and susceptibility test was conducted in Bacteriology Laboratory of IbneSina, Chattogram. The samples were collected and processed following standard microbiological techniques and an antibiotic susceptibility test was done on pure culture isolates using disc-diffusion method for the commonly used antibiotics. The data were analyzed by using SPSS version 20 and the results were summarized by using tables and graphs. Results: Out of 340 blood culture done, 62 (18.24%) were positive. Among them 61.3% were of early onset sepsis. The predominant bacteria isolated was Klebsiella spp. 27 (43.6%) followed by Coagulase negative staphylococci 12(19.4%), Salmonella typhi 10 (16.1%), E. coli 6 (9.6%) and Pseudomonas 5 (8.0%). Antibiotic susceptibility tests showed that the most sensitive antibiotics to Gram-negative organisms wereImipenem (81-100%), Tazobactam-Piperacillin (74-100%), Amikacin (67-90%), Ceftriaxone (60-100%) and Levofloxacin (63-80%). Maximum resistance among Gram-negative organisms were seen in Ampicillin (60-100%), Cotrimoxazole (60-100%) and Cefixime (30-80%). Among Gram-positive organisms, all strains (100%) were sensitive to Linezolid and Vancomycin. Other alternates with good sensitivity were Amikacin (92%), Imipenem (83%), Ceftriaxone (83%) and Levofloxacin (75%). While maximum resistance was seen to Ampicillin (83%), Amoxiclav (75%), Cefixime (75%) and Ciprofloxacin (75%). Conclusions: In the present study, most of the pathogens isolated from blood cultures were Gram negative and they showed high resistance to commonly used antibiotics. Therefore, rational use of antibiotics after sensitivity testing should be practiced. IAHS Medical Journal Vol 7(1), June 2024; 68-73

Association of gut microbiota imbalance with risk of postoperative infections in patients with left ventricular assist device

Abstract Background Infections are the most common complications following left ventricular assist device (LVAD) implantation and associated with adverse events. Gut microbial imbalance may predispose to mucosal colonization with pathogens, resulting in a risk of subsequent serious infections. However, it remains unclear whether gut microbiota imbalance is associated with postoperative infections in patients with LVAD. Purpose The aim of this study was to investigate whether gut microbiota imbalance was associated with postoperative infections in patients with LVAD. Methods We prospectively examined 22 consecutive LVAD patients who were admitted to a university hospital for routine check-ups and had stool cultures taken between March 2022 and December 2023. All patients had no signs of infection. The patients were divided into two groups according to positive (normal bacterial flora and other bacteria including Streptococcus viridans, Klebsiella, or Extended-spectrum β-lactamase Escherichia coli; n = 7) and negative (normal bacterial flora only; n = 15) for stool culture. The primary outcome was serious infection requiring hospitalisation treated with intravenous antimicrobial agents. Results Patients were predominantly male (68%) and the median age was 49 (interquartile range [IQR] 29-58) years. There were no significant differences in age, sex, primary aetiology of heart failure, type of LVAD devices, time on LVAD support, the history of infection, or antibiotics use within six months between the groups. During a median follow-up period of 316 days (IQR 242-559), the primary outcome occurred in seven patients (32%), including four hospitalisation for driveline infections, two pneumoniae and bacterial bloodstream infections, and one lung abscess and bacterial bloodstream infection. Kaplan–Meier analysis showed that the adverse events more frequently occurred in LVAD patients with positive for stool culture (P = 0.010) (Figure). A multivariable Cox regression analysis showed that positive for stool culture was independently associated with an increased subsequent risk of the primary outcome (hazard ratio 6.99, 95% confidence interval 1.17-41.7, P = 0.033), even after adjustments for age, male, body mass index, diabetes, INTERMACS profile, mechanical circulatory support, serum creatinine, serum albumin, and white blood cell count, which are known to be strong determinants of worse clinical outcomes in patients with LVAD. Conclusions In patients with LVAD, gut microbial imbalance was associated with subsequent serious infections. These findings suggest that the screening of stool culture might be useful for early identification of high-risk patients for infectious complication after LVAD implantation.

Incidence of bacterial blood stream infections in patients with acute GVHD.

Bacterial bloodstream infections (BSI) can be a substantial contributor to complications of GVHD treatment. The aim of this study was to determine the risk for BSI from neutrophil engraftment through day 100 post transplant in patients with acute GVHD (AGVHD) based on organ involvement and severity. Patients (n = 4064) who underwent an allogeneic hematopoietic stem cell transplant (HCT) reported to the CIBMTR registry were analyzed. Grade II-IV AGVHD occurred in 1607 (39.5%) patients and was associated with a greater day-100 incidence of post engraftment BSI than with grade 0/I (24.9 vs. 15.3%). Patients with grade III/IV AGVHD had the highest BSI risk (HR 2.45; 95% CI 1.99-3.0; p < 0.0001). Lower GI involvement increased BSI risk (HR 1.54; 95% CI 1.17-2.02; p = 0.0019). BSI post-engraftment through day 100 was associated with worse survival (HR 1.64, 95% CI 1.43-1.87; p < 0.001) and higher non-relapse mortality (NRM), (HR 2.22; 95% CI 1.91-2.59; p < 0.001). Those with stage III/IV GI involvement are at highest risk for BSI. Future studies evaluating novel methods for preventing BSI in these high risk populations are needed to reduce mortality associated with AGVHD.

A single-center analysis of pathogenic bacteria distribution and drug resistance in bacterial bloodstream infections among patients with hematological diseases

Objective: To analyze the distribution and drug resistance of pathogens of bacterial bloodstream infection in patients with hematological diseases in the Department of Hematology of Tianjin Medical University General Hospital, and to provide etiological data for clinical empirical anti-infection treatment. Methods: A retrospective analysis was conducted on the general clinical information, pathogenic bacteria and drug susceptibility test results of patients with hematological diseases diagnosed with bacterial bloodstream infection by menstrual blood culture in our center from January 2016 to December 2022. Results: Patients included 498 inpatients, with a total of 639 bacterial strains. Among the patients, 86.9% patients had malignancies, and 76.7% had agranulocytosis. Symptoms of concurrent infections, including those of the respiratory tract, oral mucosa, skin and soft tissues, and abdominal sources were observed in 68.3% patients. Gram-negative bacteria (G(-)) accounted for 79.0% of the isolated bacteria, and gram-positive bacteria (G(+)) accounted for 21.0%. The top five isolated pathogens were Klebsiella pneumoniae (22.5%), Escherichia coli (20.8%), Pseudomonas aeruginosa (15.0%), Enterococcus faecium (5.5%), and Stenotrophomonas maltophilum (5.0%). Escherichia coli exhibited a decreasing trend of resistance to quinolones, cephalosporins, and carbapenems. Klebsiella pneumoniae exhibited increasing rates of resistance to quinolones and cephalosporins between 2016 and 2018, but the rated decreased after 2019. The resistance rate to carbapenems exhibited by Pseudomonas aeruginosa was approximately 20%. Carbapenem-resistant strains of Pseudomonas aeruginosa strains were first detected in 2017, with a peak resistance rate of 35.7%, detected in 2019. A 60.0% resistance rate to methicillin was observed in methicillin-resistant coagulase-negative staphylococci (MRCNS), and one case of linezolid-resistant MRCNS was detected. Conclusions: Pathogenic bacteria of bacterial bloodstream infections were widely distributed in our center, and precautions are warranted against carbapenem resistant P. aeruginosa and Klebsiella pneumoniae.

Clinical Characteristics, Management, and Outcomes of Bacteremia in Children with Cancer: A Retrospective Study

Abstract Background Bacteremia is a common infectious complication among pediatric oncology patients, yet management practices are not standardized. Antibiotic treatment courses as short as seven days are supported by literature and could improve patient quality of life and resource use. However, it is not known if short courses are associated with greater treatment failure in immunocompromised patients. Methods We conducted a retrospective study at St. Jude Children’s Research Hospital, including patients with a laboratory confirmed bloodstream bacterial infection between April 1, 2022, and March 31, 2023. Clinical characteristics such as age, gender, type of malignancy, phase of treatment, underlying chronic conditions, and clinical sites of infection were collected. Antibiotics used, duration of therapy, and route of administration were also gathered to examine clinical management. Clinical outcomes were measured by documenting ICU admission, oxygen, fluid and vasopressor requirements, date of hospital discharge, bacteremia recurrence, and mortality. Results 86 patients contributed 112 bacteremia episodes that met eligibility criteria. Severe neutropenia was present at onset in 68% of all episodes and 32% of patients did not have neutrophil recovery over 500 cells/ml during the episode. Gram-negative organisms accounted for 52% of isolated organisms, with the most common organisms isolated overall being Escherichia coli (19%), followed by Klebsiella pneumoniae (14%), and Viridans group streptococcus (14%). The median length of antibiotic treatment was 12 days. Treatment duration was not associated with oncologic diagnosis or Gram-negative versus Gram-positive infection. Conclusion Bacteremia occurs more frequently in patients who are neutropenic, especially those who are severely neutropenic with an absolute neutrophil count less than 500 cells/mL. Treatment duration is not associated with primary cancer diagnosis or type of bacteremia. In this single high resource setting, bloodstream infections resulted in significant morbidity, resource use, and a mortality rate of 8%, highlighting opportunities for investigation to improve clinical practices.

The impact of delayed versus early administration of granulocyte colony-stimulating factor following autologous hematopoietic stem cell transplantation on transplantation outcome.

Granulocyte colony-stimulating factor (G-CSF) is routinely administered after autologous hematopoietic stem cell transplantation (auto-HSCT) to decrease the duration of neutropenia and diminish the incidence of febrile neutropenia. Nevertheless, the most advantageous timeframe for administering G-CSF in the transplantation setting remains elusive. We conducted a cross-sectional study of 200 patients diagnosed with hematological malignancies who underwent auto-HSCT between July 2017 and January 2022. Patients were divided into two groups of 100 individuals based on the timing of G-CSF administration after auto-HSCT. In the first group, G-CSF was administered on post-transplantation day +1, while in the second group, G-CSF was administered on post-transplantation day +5. Patient demographics and clinical outcomes, including time to neutrophil engraftment, time to platelet engraftment, length of hospital stay, duration of fever, and incidence of bacterial and fungal bloodstream infections, were compared between the two groups. We identified a significantly shorter platelet engraftment time in the day +5 group than in the day +1 group (P<0.001), though the groups were similar regarding neutrophil engraftment time. The total number of G-CSF injections differed significantly according to the administration schedule. The number of red blood cells and length of hospital stay was greater in the day +1 group (all P<0.001). The incidence of bacterial and fungal bloodstream infections and duration of fever did not differ between the groups. Delayed administration of G-CSF on day +5 is as effective as early administration and can positively influence platelet engraftment, transfusion support, and hospitalization time.

Safety and efficacy of G-CSF after allogeneic hematopoietic cell transplantation using post-transplant cyclophosphamide: clinical and in vitro examination of endothelial activation.

Since 2021 the use of G-CSF was implemented in allo-HCT with PTCY-based prophylaxis with the aim of shortening the aplastic phase and reducing infectious complications. This study investigates the effectiveness of this change in protocol performed at our institution. One-hundred forty-six adults undergoing allo-HCT with PTCY-based prophylaxis were included, and among them, 58 (40%) received G-CSF. The median of days to neutrophil engraftment was shorter in the G-CSF group (15 vs. 20 days, p < 0.001). Patients receiving G-CSF had a lower incidence of day +30 bacterial bloodstream infections (BSI) than the rest (20.7% vs. 47.7%, p < 0.001). GVHD, SOS, and TA-TMA incidences were comparable between groups, and using G-CSF did not impact on survival. Endothelial activation was investigated using EASIX and by the measurement of soluble biomarkers in cryopreserved plasma samples obtained on days 0, +7, +14 and +21 of 39 consecutive patients (10 received G-CSF) included in the study. EASIX, VWF:Ag, sVCAM-1, sTNFRI, ST2, REG3α, TM and NETs medians values were comparable in patients receiving G-CSF and those who did not. Compared with allo-HCT performed without G-CSF, the addition of G-CSF to PTCY-based allo-HCT accelerated neutrophil engraftment contributing on decreasing BSI incidence, and without inducing additional endothelial activation.

Infection characteristics among Serratia marcescens capsule lineages.

Serratia marcescens is a healthcare-associated pathogen that causes bloodstream infections, pneumonia, and urinary tract infections. The capsule polysaccharide of S. marcescens is a critical fitness determinant during infection and recent work established the relationship between capsule locus (KL) genetic sequences within the species. Strains belonging to KL1 and KL2 capsule clades produce sialylated polysaccharides and represent the largest subpopulation of isolates from clinical origin while the S. marcescens type strain and other environmental isolates were classified as KL5. In this work, the contribution of these and other capsules to pathogenesis in multiple infection models was determined. Using a murine tail vein injection model of bacteremia, clinical strains demonstrated capsule-dependent colonization of spleen, liver, and kidney following inoculation. The KL5 strain, in contrast, exhibited no loss of survival in this model when capsule genes were deleted. Furthermore, the wild-type KL5 strain was cleared more rapidly from both the spleen and liver compared to a KL1 strain. Similar results were observed in a bacteremic pneumonia model in that all tested strains of clinical origin demonstrated a requirement for capsule in both the primary lung infection site and for bloodstream dissemination to other organs. Finally, strains from each KL clade were tested for the role of capsule in internalization by bone marrow-derived macrophages. Only the sialylated KL1 and KL2 clade strains, representing the majority of clinical isolates, exhibited capsule-dependent inhibition of internalization, suggesting that capsule-mediated resistance to macrophage phagocytosis may enhance survival and antibacterial defenses during infection.

Outcomes of older adults undergoing allogeneic hematopoietic cell transplantation with post-transplant cyclophosphamide based prophylaxis.

This study evaluates the feasibility of using post-transplant cyclophosphamide (PTCY) prophylaxis in allo-hematopoietic cell transplantation (HCT) for adults aged 65 and older. PTCY is increasingly used to prevent graft-versus-host disease (GVHD) across all donor types, but concerns remain about potential risks, especially in older patients. Fifty-seven adults aged 65 or older with hematological malignancies, undergoing their first allo-HCT with PTCY prophylaxis between January 2011 and January 2023 were included. Overall, 94.8% of patients achieved primary engraftment. The median durations for neutrophil and platelet engraftments were 19 and 21 days. The day +30 cumulative incidence of bacterial bloodstream infection was 43.9%. No CMV reactivations occurred within the first 100 days after letermovir implementation. The day +180 cumulative incidences of grade II-IV and III-IV acute GVHD, and the 2-year cumulative incidence of moderate/severe chronic GVHD were 26.3%, 10.5%, and 4.8%. Eighteen patients (31.6%) relapsed, and 30 (52.6%) died, with relapse (16.4%) and infection (11.5%) being the main causes of death. The estimated 2-year overall survival, non-relapse mortality, cumulative incidence of relapse, and GVHD-free relapse-free survival rates were 45.5%, 27.1%, 33.9%, and 37.0%. Adults aged 70 or older had similar outcomes to those aged 65-69. This study confirms the safety and feasibility of PTCY-based allo-HCT in older adults.

The Etiology of Bloodstream Infections at an Italian Pediatric Tertiary Care Hospital: A 17-Year-Long Series.

Knowledge of epidemiology is essential for guiding correct antibiotic prescription, reducing bacteremia-associated mortality, and implementing targeted infection control programs. However, only a few studies have reported on the epidemiology of bloodstream infections (BSIs) in pediatrics. We performed a retrospective analysis of all BSIs (excluding those caused by common skin contaminants) diagnosed from 2006 to 2022 in patients younger than 18 years who were treated at an Italian pediatric tertiary care hospital. Overall, 2395 BSIs were recorded, including 2207 (92.15%) due to bacteria and 188 (7.85%) due to fungi. The incidence rate (BSIs/10,000 hospital discharges, IR) of bacterial BSIs significantly increased during the study period. In particular, BSIs caused by S. aureus (including MRSA), Enterobacterales (including ESBL and AmpC producers), Enterococcus spp., and P. aeruginosa became more common. The frequency of carbapenem-resistant strains was <1% and stable over time. Conversely, there was a significant reduction in the incidence of BSIs due to S. pneumoniae. The BSIs were stratified by patient age, and S. aureus was the most frequent cause of BSIs in all age groups, while E. coli was the most frequent in the Enterobacterales family. S. agalactiae was the third most frequent cause of neonatal early-onset BSIs. The prevalence of Enterococcus spp. increased in the subgroups from 8 days to 5 years of age, while P. aeruginosa became more prevalent in children over 5 years of age. S. aureus was also the most frequent isolate in both community- and hospital-onset BSIs, followed by E. coli. The prevalence of multidrug-resistant (MDR) pathogens was very low. It was <5% for both Gram-positive (i.e., MRSA and VRE) and Gram-negative (ESBL, AmpC, and carbapenem-resistant) pathogens, and MDR pathogens were almost exclusively detected in hospital-onset BSIs. Fungi accounted for just under 8% of BSIs. C. albicans was the most frequently isolated strain, followed by C. parapsilosis. Notably, the IR of fungemia did not change significantly during the study period, in spite of an increase in the absolute number of events. The continuous monitoring of local epidemiology is essential to identify changes in the IRs of pathogens and antibiotic susceptibility and to guide antibiotic treatments, especially in the phase when antibiograms are not yet available.

New Insights Into Infections' Risk of Adolescents and Young Adults Treated for Acute Lymphoblastic Leukemia.

This study aims to compare the infections' risk between adolescents and young adults (AYAs), treated for acute lymphoblastic leukemia, and pediatric population. We also focused on their bacterial and fungal infection specificities. This case-control study investigated the occurrence of bacterial bloodstream infection (BSI) and proven and probable invasive fungal infection (IFI) in AYAs (15-25 years old) and children (1-14 years old) treated for acute lymphoblastic leukemia between January 2013 and December 2020 in 2 French tertiary pediatric and 2 referral adult hematological centers, independent of their treatment protocol. We also evaluated the impact of these infections on morbidity (necessity of intensive care) and mortality. We analyzed 83 AYAs and 230 children and found that AYAs developed significantly more IFI than the pediatric population (22% vs. 10%, P = 0.007), regardless of their care center (adult or pediatric). Furthermore, the occurrence of BSI was similar between the 2 populations (48% vs. 51%, P = 0.66). Moreover, the occurrence of infection increased with the AYAs' risk group of treatment: standard, medium or high risk (P = 0.021 for BSI and P = 0.029 for IFI). Finally, the mortality rate is only 1.3% after a BSI whereas it increases to 4.9% after IFI. AYAs have their own specificity with an increased risk of fungal infection compared to children, independent of the care center. Antifungal prophylaxis should be contemplated, especially for patients classified in high-risk groups.

Reduced Dose of Post-Transplant Cyclophosphamide with Tacrolimus for the Prevention of Graft-versus-Host Disease in HLA-Matched Donor Peripheral Blood Stem Cell Transplants: A Prospective Pilot Study.

PTCY 50 mg/kg/day on days +3/+4 is an excellent strategy to prevent GVHD. However, its use is associated with adverse outcomes such as delayed engraftment, increased risk of infection, and cardiac complications. This pilot study evaluates the efficacy and toxicity of a reduced dose of PTCY (40 mg/kg/day) combined with tacrolimus in 22 peripheral blood HLA-matched alloHSCT patients. At day +100, the cumulative incidences of grade II-IV and III-IV acute GVHD were 18.2% and 4.5%, respectively. No grade IV acute GVHD or steroid-refractory disease was observed. The cumulative incidences of all-grade and moderate-severe chronic GVHD at 1-year were 11.4% and 6.4%, respectively. No patient died from transplant-related complications. Two-year OS and RFS were 77.1% and 58.3%, respectively. All patients engrafted, with neutrophil and platelet recovery occurring at a median of 15 (IQR 14-16) and 16 days (IQR 12-23), respectively. The cumulative incidences of bloodstream bacterial infections, polyomavirus BK hemorrhagic cystitis, HHV6 reactivation, CMV reactivation, and fungal infections were 13.6%, 9.1%, 9.1%, 4.6%, and 6%, respectively. Only one early cardiac event was observed. These results suggest that PTCY 40 mg/kg/day on a +3/+4 schedule provides adequate immunosuppression to allow for engraftment and prevent clinically significant GVHD with a low toxicity profile.

Ciprofloxacin versus levofloxacin prophylaxis in hematopoietic stem cell transplantation: A randomized trial

ObjectivesWe aimed to assess whether there is a difference between ciprofloxacin and levofloxacin as prophylaxis in hematopoietic stem cell transplant (SCT) recipients. MethodsThis is a prospective, randomized trial in patients receiving SCT at Henry Ford Health in the United States of America. We randomly assigned patients (1:1) to receive ciprofloxacin or levofloxacin. The primary outcome was incidence of bloodstream bacterial infections (BSI) up to day 60 after SCT. ResultsBetween June 4, 2018, and May 23, 2022, we randomly assigned 308 consecutive patients to receive ciprofloxacin (154 patients) or levofloxacin (154 patients). BSI was similar in both the ciprofloxacin and levofloxacin groups (18 [11.7%] vs 18 [11.7%]). Pneumonia was more frequent in the ciprofloxacin group compared to the levofloxacin group (18 [18%] vs 7 [23%]; relative risk 2.57, 95% CI 1.11-5.98; p = 0.028). There were no differences in neutrophil engraftment, fever, Clostridium difficile infection, relapse incidence, overall survival, nonrelapse mortality, length of stay post-SCT, or intensive care unit admission. ConclusionAlthough both prophylaxis regimens demonstrated the same efficacy in SCT recipients, levofloxacin prophylaxis led to less pneumonia in the first 60 days post-SCT. Trial RegistrationThis study is registered on ClinicalTrials.gov, NCT03850379.

Multiple lung abscesses and cold agglutinin syndrome following coronavirus disease 2019: a case report

BackgroundCold agglutination syndrome is a subtype of autoimmune hemolytic anemia. The condition is referred to as “cold” because the antibodies become active and induce hemolysis at cold temperatures, typically 3–4 °C, which is not always the case in other kinds of autoimmune hemolytic anemia. Whereas primary cold agglutination syndrome may occur in the absence of underlying conditions, secondary cold agglutination syndrome is associated with the presence of underlying infections, including coronavirus disease 2019.Case presentationWe report the case of a 69-year-old Japanese woman with periodontitis who was referred to our hospital with complaints of brown-colored urine and chest pain. Her hemoglobin level was 6.1 g/dL. Computed tomography revealed multiple lung abscesses. Her direct antibody test results were positive (2+) for anti-complement direct antiglobulin and negative for immunoglobulin G, and her cold agglutinin titer was elevated at 1:4096. Workup for anemia revealed a positive result for cold agglutination syndrome. The patient had received the fourth dose of coronavirus disease 2019 vaccination. Nasopharyngeal swab test for detecting severe acute respiratory syndrome coronavirus 2 using a real-time reverse-transcription polymerase chain reaction gave a cycle threshold value of 42.3, and the level of virus-specific immunoglobulin G was elevated at 7.71 S/C (normal range −1.4 S/C).ConclusionA decrease in hemoglobin in patients with coronavirus disease 2019 may be associated with secondary cold agglutination syndrome. The patient was hypothesized to have developed multiple lung abscesses with secondary cold agglutination syndrome following coronavirus disease 2019. Thus, following coronavirus disease 2019, patients can develop secondary cold agglutination syndrome, which could worsen owing to associated bloodstream bacterial infections.

Clinical outcomes of carbapenem-resistant gram-negative bacterial bloodstream infection in patients with end-stage renal disease in intensive care units: a multicenter retrospective observational study.

Carbapenem-resistant gram-negative bacteria (CRGNB) present a considerable global threat due to their challenging treatment and increased mortality rates, with bloodstream infection (BSI) having the highest mortality rate. Patients with end-stage renal disease (ESRD) undergoing renal replacement therapy (RRT) face an increased risk of BSI. Limited data are available regarding the prognosis and treatment outcomes of CRGNB-BSI in patients with ESRD in intensive care units (ICUs). This multi-center retrospective observational study included a total of 149 ICU patients with ESRD and CRGNB-BSI in Taiwan from January 2015 to December 2019. Clinical and microbiological outcomes were assessed, and multivariable regression analysis was used to evaluate the independent risk factors for day-28 mortality and the impact of antimicrobial therapy regimen on treatment outcomes. Among the 149 patients, a total of 127 patients (85.2%) acquired BSI in the ICU, with catheter-related infections (47.7%) and pneumonia (32.2%) being the most common etiologies. Acinetobacter baumannii (49.0%) and Klebsiella pneumoniae (31.5%) were the most frequently isolated pathogens. The day-28 mortality rate from BSI onset was 52.3%, and in-hospital mortality was 73.2%, with survivors experiencing prolonged hospital stays. A higher Sequential Organ Failure Assessment (SOFA) score (adjusted hazards ratio [aHR], 1.25; 95% confidence interval [CI] 1.17-1.35) and shock status (aHR, 2.12; 95% CI 1.14-3.94) independently predicted day-28 mortality. Colistin-based therapy reduced day-28 mortality in patients with shock, a SOFA score of ≥ 13, and Acinetobacter baumannii-related BSI. CRGNB-BSI led to high mortality in critically ill patients with ESRD. Day-28 mortality was independently predicted by a higher SOFA score and shock status. In patients with higher disease severity and Acinetobacter baumannii-related BSI, colistin-based therapy improved treatment outcomes.

Impact of multidrug resistance on outcomes in hematologic cancer patients with bacterial bloodstream infections

Despite the improved outcomes in patients with hematological malignancies, infections caused by multidrug-resistant organisms (MDROs) pose a new threat to these patients. We retrospectively reviewed the patients with hematological cancer and bacterial bloodstream infections (BSIs) at a tertiary hospital between 2003 and 2022 to assess the impact of MDROs on outcomes. Among 328 BSIs, 81 (24.7%) were caused by MDROs. MDRO rates increased from 10.3% (2003–2007) to 39.7% (2018–2022) (P < 0.001). The 30-day mortality rate was 25.0%, which was significantly higher in MDRO-infected patients than in non-MDRO-infected patients (48.1 vs. 17.4%; P < 0.001). The observed trend was more pronounced in patients with newly diagnosed diseases and relapsed/refractory disease but less prominent in patients in complete remission. Among MDROs, carbapenem-resistant Gram-negative bacteria exhibited the highest mortality, followed by vancomycin-resistant enterococci, methicillin-resistant Staphylococcus aureus, and extended-spectrum β-lactamase-producing Enterobacteriaceae. Multivariate analysis identified independent risk factors for 30-day mortality as age ≥ 65 years, newly diagnosed disease, relapsed/refractory disease, MDROs, polymicrobial infection, CRP ≥ 20 mg/L, and inappropriate initial antibiotic therapy. In conclusion, MDROs contribute to adverse outcomes in patients with hematological cancer and bacterial BSIs, with effects varying based on the underlying disease status and causative pathogens. Appropriate initial antibiotic therapy may improve patient outcomes.

Immunosuppression at ICU admission is not associated with a higher incidence of ICU-acquired bacterial bloodstream infections: the COCONUT study

BackgroundImmunosuppression at intensive care unit (ICU) admission has been associated with a higher incidence of ICU-acquired infections, some of them related to opportunistic pathogens. However, the association of immunosuppression with the incidence, microbiology and outcomes of ICU-acquired bacterial bloodstream infections (BSI) has not been thoroughly investigated.MethodsRetrospective single-centered cohort study in France. All adult patients hospitalized in the ICU of Lille University-affiliated hospital for > 48 h between January 1st and December 31st, 2020, were included, regardless of their immune status. Immunosuppression was defined as active cancer or hematologic malignancy, neutropenia, hematopoietic stem cell and solid organ transplants, use of steroids or immunosuppressive drugs, human immunodeficiency virus infection and genetic immune deficiency. The primary objective was to compare the 28-day cumulative incidence of ICU-acquired bacterial BSI between immunocompromised and non-immunocompromised patients. Secondary objectives were to assess the microbiology and outcomes of ICU-acquired bacterial BSI in the two groups.ResultsA total of 1313 patients (66.9% males, median age 62 years) were included. Among them, 271 (20.6%) were immunocompromised at ICU admission. Severity scores at admission, the use of invasive devices and antibiotic exposure during ICU stay were comparable between groups. Both prior to and after adjustment for pre‐specified baseline confounders, the 28-day cumulative incidence of ICU-acquired bacterial BSI was not statistically different between immunocompromised and non-immunocompromised patients. The distribution of bacteria was comparable between groups, with a majority of Gram-negative bacilli (~ 64.1%). The proportion of multidrug-resistant bacteria was also similar between groups. Occurrence of ICU-acquired bacterial BSI was associated with a longer ICU length-of-stay and a longer duration of invasive mechanical ventilation, with no significant association with mortality. Immune status did not modify the association between occurrence of ICU-acquired bacterial BSI and these outcomes.ConclusionThe 28-day cumulative incidence of ICU-acquired bacterial BSI was not statistically different between patients with and without immunosuppression at ICU admission.

Prediction of carbapenem-resistant gram-negative bacterial bloodstream infection in intensive care unit based on machine learning

BackgroundPredicting whether Carbapenem-Resistant Gram-Negative Bacterial (CRGNB) cause bloodstream infection when giving advice may guide the use of antibiotics because it takes 2–5 days conventionally to return the results from doctor's order.MethodsIt is a regional multi-center retrospective study in which patients with suspected bloodstream infections were divided into a positive and negative culture group. According to the positive results, patients were divided into the CRGNB group and other groups. We used the machine learning algorithm to predict whether the blood culture was positive and whether the pathogen was CRGNB once giving the order of blood culture.ResultsThere were 952 patients with positive blood cultures, 418 patients in the CRGNB group, 534 in the non-CRGNB group, and 1422 with negative blood cultures. Mechanical ventilation, invasive catheterization, and carbapenem use history were the main high-risk factors for CRGNB bloodstream infection. The random forest model has the best prediction ability, with AUROC being 0.86, followed by the XGBoost prediction model in bloodstream infection prediction. In the CRGNB prediction model analysis, the SVM and random forest model have higher area under the receiver operating characteristic curves, which are 0.88 and 0.87, respectively.ConclusionsThe machine learning algorithm can accurately predict the occurrence of ICU-acquired bloodstream infection and identify whether CRGNB causes it once giving the order of blood culture.