Clinical relevance of procalcitonin values in bacteremia.

INTRODUCTION: The aim of this study was to investigate procalcitonin levels according to the causative pathogens of bacteremia. The relationships between the clinical outcomes and procalcitonin levels were also studied. METHODS: From among 452 patients, 507 cases of positive blood culture were included in the present study. Procalcitonin levels were studied according to the pathogen types. The prevalence of septic shock and the mortality rates were also studied in four groups stratified by the procalcitonin levels (groups 1, 2, 3, and 4 had procalcitonin levels of <0.5 ng/mL, 0.5 ≤ 2.0 ng/mL, 2.0 < 10 ng/mL, and ≥10 ng/mL, respectively). RESULTS: The procalcitonin levels were significantly higher in bacteremia cases with Gram-negative rods (19.50 ng/mL), such as Escherichia coli (32.5 ng/mL), than those with Gram-positive rods (8.45 ng/mL) or Gram-positive cocci (9.21 ng/mL) (p < 0.01). The 28-day mortality rates in groups 1, 2, 3, and 4 were 6.0%, 12.0%, 14.9%, and 19.8%, respectively. The procalcitonin levels of samples taken before or on the same day of blood cultures were significantly lower than those taken one day after blood cultures. Multiple logistic regression analysis showed that C-reactive protein and procalcitonin ≥10 ng/mL were independently associated with a higher risk of mortality within 28 days. CONCLUSIONS: The PCT levels were higher in cases of bacteremia caused by GNR than those caused by GPR or GPC. The 28-day mortality rate increased as the PCT levels increased. Clinical importance of early evaluations and appropriate interpretation of procalcitonin levels for bacteremia were indicated.

First case report of infection due to Cupriavidus gilardii in a patient without immunodeficiency: a case report.

BACKGROUND: Cupriavidus gilardii is an aerobic, Gram-negative, glucose-nonfermenting rod that was first identified in 1999. Because of the difficulty in accurate species identification of C. gilardii, there are few case reports of infection caused by this organism. In previous reports, C. gilardii has been characterized as an organism with low pathogenicity that causes opportunistic infections. CASE PRESENTATION: We encountered a case of pacemaker-associated bloodstream infection caused by C. gilardii in a 90-year old woman without obvious immunodeficiency. We identified the isolates as C. gilardii by sequencing of the 16S rRNA gene. The patient was treated with removal of the lead and administration of antimicrobial agents. Because of the acquisition of antibiotic resistance during antibiotic treatment, the antimicrobial agent was changed during the course of treatment. CONCLUSIONS: To our knowledge, this is the first report of an infection caused by this organism in a patient without obvious immunodeficiency. Although the true pathogenicity of C. gilardii is unclear, the possibility that it exerts pathogenicity not only in persons with immunodeficiency but also in immunocompetent persons is suggested.

Anaerobic gram-negative rod bacteremia as a marker of gastrointestinal cancer in Japanese patients: a single-center retrospective study.

BACKGROUND: Gram-negative rod (GNR) bacteremia has been suggested as a clinical marker of occult cancer; however, no studies are available in this regard in the Japanese population. Here, we investigated the risk factors for gastrointestinal cancer with GNR bacteremia. METHODS: Patients with GNR bacteremia admitted to St. Luke's International Hospital between January 2011 and July 2021 were included. The clinical data of patients with and without cancer, 1 year before and after GNR bacteremia diagnosis, were compared. Univariate analysis was performed using χ2 and Fisher's exact tests for categorical variables and the Mann-Whitney U test for continuous variables, while multivariable analysis was performed using logistic regression analysis, and a P of <0.05 was considered statistically significant. RESULTS: Of 2,296 GNR bacteremia-positive patients, 96 were associated with gastrointestinal cancer, and univariate analysis showed significant differences between the gastrointestinal cancer and comparison groups in terms of mean body mass index (BMI; 20.5 vs. 21.8 kg/m2), Enterobacterales detection (64.6% vs. 81.3%), and anaerobic GNR detection (24.0% vs. 8.5%). Thirty-five (36%) and 61 (64%) patients had upper and lower gastrointestinal cancer, respectively. There were 23 patients with anaerobic GNR bacteremia related to 24 strains (upper and lower gastrointestinal cancer, 5 and 18 cases, respectively). Multivariate analysis identified anaerobic GNR [odds ratio, 3.440; 95% confidence interval (CI): 2.085-5.675, P<0.001] as a significant risk factor for cancer. CONCLUSIONS: Anaerobic GNR in blood cultures may be a risk factor for gastrointestinal cancer. Therefore, it is necessary consider cancer workup, such as endoscopy, for patients with anaerobic GNR bacteremia.

Pleural Empyema Due to Proteus Mirabilis in an Adult: A Rarely Encountered Clinical Scenario.

The presence of Proteus species in the pleural space is an uncommonly reported entity and is rarely seen even in patients with compromised immune status. We report a case of pleural empyema due to Proteus species in an adult oral cancer patient receiving chemotherapy for academic interest and for generating awareness regarding an expanded pathogenic spectrum of the organism. A 44-year-old salesman, non-smoker and non-alcoholic, presented with sudden-onset shortness of breath, left-sided chest pain, and low-grade fever of one-day duration. He had been recently diagnosed with adenocarcinoma of the tongue and had received two cycles of chemotherapy. After clinical and radiographic evaluation, the patient was diagnosed with left-sided empyema. Following thoracocentesis, the aspirated pus sent for bacterial culture yielded pure growth of Proteus mirabilis. Appropriately modified antibiotic therapy with parenteral piperacillin-tazobactam followed by cefixime, tube drainage, and other supportive therapy resulted in a favorable outcome. After three weeks of hospitalization, the patient was discharged for further planned management of his underlying condition. Though uncommon, the possibility of Proteus species should be kept in mind as a causative agent of thoracic empyema in adults, especially in immunocompromised patients with cancer, diabetes, and renal diseases. The so-called common microorganisms of empyema appear to have altered over time, influenced by anticancer therapy and underlying host immune status. Rapid diagnosis and appropriate antimicrobial therapy usually result in a favorable outcome.

Impact of Gram-Negative Rod Bacteremia Rapid Diagnostic Testing and Real-Time Clinical Pharmacist Intervention.

Background: The optimal method for implementing rapid diagnostic testing (RDT) into clinical practice has not been determined for gram-negative rod (GNR) bacteremia. At our institution, RDT was implemented in conjunction with real-time notification of results to decentralized clinical pharmacists. Objective: To determine the impact of RDT result notification plus real-time clinical pharmacist review on the management of GNR bacteremia. Methods: This retrospective, matched cohort study included patients with a positive blood culture for a GNR on the BIOFIRE® Blood Culture Identification 2 panel from September 2020 to August 2021 (historical) and October 2021 to September 2022 (interventional). Exclusion criteria were polymicrobial bacteremia, discrepant RDT results from traditional culture, 24-hour mortality, and comfort care or not admitted at the time of RDT result. Patients were matched based on age, pathogen, and resistance. The primary endpoint was time from Gram stain to appropriate antibiotic therapy. Results: This study consisted of 240 patients (n = 120 historical, n = 120 interventional). Escherichia coli was isolated in 71% of patients with extended-spectrum beta-lactamase-producing organisms isolated in 8%. There was no difference in median time to appropriate therapy (0 vs 0 hours, P = 0.28). There was a statistically significant decrease in time to first organism-directed change in therapy (40 vs 11 hours; P < 0.01). Length of stay, days of anti-pseudomonal therapy, and inpatient mortality did not differ between groups. Conclusion: Implementation of RDT plus real-time clinical pharmacist review did not significantly decrease time to appropriate therapy in patients with GNR bacteremia but significantly reduced time to organism-directed antibiotic changes.

Silver-Mixed Port Reduces Venous Access Port Related Infection Rate Compared to Non-Silver-mixed Port: A Single-center Retrospective Analysis.

PURPOSE: Totally implantable venous access ports (TIVAPs) are increasingly used as safe and convenient central venous access devices. However, several TIVAP-related complications occur, with port/catheter infection being most common. Silver-mixed ports have recently been introduced in anticipation of reducing TIVAP infection. This study aimed to investigate the efficacy of this device in reducing port infection by examining groups with and without silver-mixed devices. MATERIALS AND METHODS: From April 2017 to July 2022, silver-mixed ports (S group) and non-silver-mixed port group (NS group) were reviewed at our institution. The incidence of TIVAP-related infections, patient characteristics, and bacteriological data were evaluated. Univariate and multivariate analyses were used to evaluate risk factors for TIVAP-related infection. RESULTS: A total of 607 patients (S group, n = 203; NS group, n = 404) were enrolled. The rates of TIVAP-related infection were 3.0% (n = 6) and 7.7% (n = 31) in the S and NS groups, respectively. The incidence of total infection per 1000 catheter-days were 0.114 and 0.214 the S and NS groups, respectively. In the entire group, the rates of infection were 6.1% (n = 37) and the incidence of total infection per 1000 catheter-days was 0.187. Univariate and multivariate analyses revealed a significantly lower TIVAP-related infection rate in S group than NS group (p = 0.0216, odds ratio = 2.88 confidence interval: 1.17-7.08). No gram-negative rods were detected in the S group as port infection. CONCLUSION: Silver-mixed port may be feasible in preventing port infection. LEVEL OF EVIDENCE: Level 3, Local non-random sample.

Evaluating antibiotic therapy for ventilator-associated pneumonia caused by gram-negative bacilli.

Introduction: Ventilator-associated pneumonias (VAPs) are a complication of mechanical ventilation in the intensive care unit (ICU) that increase length of stay, morbidity, and mortality. While identifying and treating infections early is paramount to improving patient outcomes, more and more data demonstrate limited courses of antibiotics improve outcomes. Prolonged (10-14 day) courses of antibiotics have remained the standard of care for pneumonia due to gram-negative bacilli (GNR). We aimed to review our GNR VAPs to assess risk factors for recurrent GNR infections. Methods: We reviewed trauma patients who developed VAP from 02/2019 through 05/2022. Demographics, injury characteristics, and outcomes were reviewed with a focus on pneumonia details including the cultured pathogen(s), antibiotic(s) used, treatment duration, and presence of recurrent infections. We then compared single episode VAPs to multiple episode VAPs among patients infected by GNRs. Results: Eleven of the fifty trauma patients admitted to the ICU suffered a VAP caused by a GNR. Of these eleven patients, six experienced a recurrent infection, four of which were caused by Pseudomonas aeruginosa and two of which were caused by Enterobacter aerogenes. Among the patients who received ten days of antibiotic treatment, half suffered a recurrence. Although, there was no difference in the microbiology or antibiotic duration between the recurrences and single episodes. Conclusion: Despite prolonged use of antibiotics, we found that the risk of recurrent or persistent infections was high among patients with VAP due to GNB. Further study is needed to determine optimal treatment to minimize the risk of these recurrences. Key message: Ventilator-associated pneumonia due to gram-negative bacilli is a rare but high morbidity complication in intensive care units. Despite prolonged duration of therapy, these infections still appear to account for many recurrent infections and further study into optimal therapy is warranted.

Impact of Persistent Multidrug-Resistant Gram-Negative Bacteremia on Clinical Outcome and Mortality.

The clinical aspects of persistent bacteremia (PB) caused by gram-negative rods (GNRs) in terms of antimicrobial resistance (AMR) and PB clearance status are unclear. This secondary analysis of a retrospective cohort study investigated differences in PB caused by Enterobacterales and glucose non-fermentative GNRs (NF-GNRs) based on AMR and PB clearance. We retrospectively surveyed medical records at Tohoku University Hospital. Patients for whom blood cultures were performed between January 2012 and December 2021 were recruited. PB cases were grouped based on AMR and PB clearance; the characteristics of PB due to each bacterial pathogen were examined. The main outcome variable was mortality. The late (30-90-day) mortality rate was significantly higher in the multidrug-resistant (MDR) group than in the non-MDR group for Enterobacterales. However, no significant difference was noted in mortality rates between NF-GNRs with and without AMR. Mortality rates tended to be higher in the non-PB-clearance group than in the clearance group for both Enterobacterales and NF-GNRs. Since the mortality rate was higher in the MDR group in the case of Enterobacterales PB, more careful management is necessary for this condition. Follow-up blood cultures and confirming the clearance of PB are useful for improving the survival rate.

Infection caused by Cupriavidus gilardii in a convalescent COVID-19 patient.

Cupriavidus gilardii is an aerobic, gram-negative bacillus that can opportunistically infect immunocompromised patients or those undergoing invasive procedures. We reported a case caused by C. gilardii in a previously basic healthy 78-year-old male, who had COVID-19 and had used corticosteroids recently. The bacterium was identified as C. gilardii by the metagenomic next-generation sequencing from the patient's bronchoalveolar lavage fluid and blood. In addition, this is the first time that we isolated C. gilardii from bronchoalveolar lavage fluid, which provides clinical experience in rare bacterial infections.

Are hematopoietic cell transplant recipients with Gram-negative bacteremia spending more time outpatient while on intravenous antibiotics? Addressing trends over 10 years at a single center.

INTRODUCTION: The increasing proportion of outpatient allogeneic hematopoietic cell transplants (HCTs) coupled with increased access of once-daily broad-spectrum antibiotics and evidence that outpatient antibiotic treatment may be safer and less costly than inpatient treatment, suggest that allogeneic HCT recipients with Gram-negative rod bacteremia (GNRBs) are increasingly being treated in ambulatory care settings. METHODS: Using data from the first GNRB event that occurred within the first 100 days posttransplantation among allogeneic HCT recipients transplanted at a single center between 2007 and 2016, we estimated the temporal trends in GNRB incidence and treatment management of GNRBs and identified if patient or infection characteristics impacted observed trends. RESULTS: A total of 11% (238/2165) of the observed allogeneic HCT recipients experienced ≥1 GNRB with available resistance data and contributed antibiotic treatment time. Patients, on average, received 55.1% of their antibiotic treatment in an outpatient setting and we observed a significant decline in the proportion of treatment time spent outpatient (crude: -3.3% [95% confidence interval: -5.0, -1.6%]). We observed similar declines in the proportion of treatment time spent outpatient among patients with similar GNRB and pretransplant complexity factors but not among patients with similar posttransplant complications (p value: .165). CONCLUSION: These results suggest that, despite increased availability of outpatient suitable treatment options, allogeneic HCT recipients with GNRBs received less treatment in outpatient settings. However, among patients with similar posttransplant complications, the lack of significant decline suggests that treatment location decisions remained consistent for patients with similar posttransplant complications. These findings suggest the need for additional interventions targeting outpatient antibiotic treatment among allogeneic HCT recipients with GNRBs.

Avrilella dinanensis gen. nov., sp. nov., a novel bacterium of the family Flavobacteriaceae isolated from human blood.

Polyphasic taxonomic analysis was performed on a novel bacterium, designated UR159T, isolated in 2016 from human blood of a septic patient hospitalized in France. Preliminary 16S rRNA gene sequence-based phylogenetic analysis indicated that strain UR159T belonged to the family Flavobacteriaceae, forming a distinct phyletic line distantly related (<94% sequence similarity) to known species of the family. Further phenotypic, chemotaxonomic and genomic analyses were performed. Cells were non-motile, oxidase-negative, catalase-positive Gram-negative rods. It was strictly aerobic yielding yellow-pigmented colonies, and was metabolically rather inert. Major fatty acids were iso-branched fatty acids, predominantly iso-C15:0 (55.5%) and iso-C17:1ω9c (8.8%). Whole genome sequencing revealed a 2.3-Mbp genome encoding a total of 2262 putative genes with a genomic DNA G+C content at 37.6mol%. The average nucleotide identity (ANI) and in silico DNA-DNA hybridization (isDDH) values between strain UR159T and the most closely related members of the Flavobacteriaceae family were <75% and <39%, respectively, much below the established cut-offs for ANI (<95-96%) and isDDH (<70%) for species and genus delineation. Average Amino Acid Identity (AAI) percentages were also estimated and were lower than 65% (cut-off proposed for genus delineation for uncultivated prokaryotes) in all cases, except for F. marinum that was just at the limit (65.1%). Based on these findings, we propose it as a new genus and species, Avrilella dinanensis gen. nov., sp. nov. (type strain UR159T=CIP 111616T=DSM 105483T).

Neisseria elongata osteomyelitis: Literature review and case report in a 63-year-old male presenting with progressive right-handed redness, swelling and pain.

INTRODUCTION: Neisseria elongata, a gram-negative rod, has been identified in 23 cases of pathogenesis in the literature, of which only 2 were osteomyelitis. Here we report the third known case of isolated N. elongata cultures in a digital osteomyelitis. PRESENTATION OF CASE: A 63-year-old male with peripheral vascular disease and lower extremity wounds presented to his vascular surgeon with right-handed redness and pain requiring urgent surgical intervention. Irrigation, debridement, and partial thumb amputation were performed, followed by treatment with a 6-week course of antibiotics. DISCUSSION: N. elongata is a rare cause of osteomyelitis and unfamiliarity with the causal organism and rod-like morphology may delay diagnosis and treatment. CONCLUSION: Gram-negative coverage should be considered in high-risk populations with cellulitis to prevent progression to fulminant abscesses, suppurative tenosynovitis and osteomyelitis.

Pantoea dispersa bacteremia in an immunocompetent patient: a case report and review of the literature.

BACKGROUND: Pantoea is a Gram-negative, non-encapsulated, non-spore-forming, ubiquitous straight rod which can be isolated from geographical and ecological sources such as plant surfaces, buckwheat seeds, human feces, and the environment. The genus Pantoea is a rare pathogen in a clinical setting, and is divided into 20 different species such as Pantoea agglomerans, Pantoea ananatis, Pantoea deleyi, Pantoea dispersa, Pantoea septica, Pantoea stewartii or Pantoea rwandensis. Pantoea dispersa has been reported to cause other infections, including respiratory infections, neonatal sepsis, and bloodstream infections. We report a case of Pantoea dispersa bacteremia caused by acute cholangitis. This is the first case report of Pantoea dispersa bacteremia caused by acute cholangitis as far as we had searched. CASE PRESENTATION: A 38-year-old Japanese woman suffered from acute cholangitis; a blood culture showed that Gram-negative rod was positive. The treatment was successful with intravenously administered meropenem, and it was switched to orally administered levofloxacin according to microbiological susceptibility. The organism was identified as Pantoea dispersa by both genetic investigation by 16S ribosomal RNA and additional biochemical tests. To the best of our knowledge, this is the first case report of Pantoea dispersa bacteremia caused by acute cholangitis. CONCLUSION: The epidemiology and clinical features of Pantoea dispersa are still unknown. More cases of infections caused by Pantoea dispersa might be revealed with advancing technical methods, such as matrix-assisted laser desorption/ionization time-of-flight mass spectrometry or 16S ribosomal RNA analysis. Physicians must know that a variety of infections caused by Pantoea dispersa could occur in immunocompromised as well as immunocompetent patients.

Gram-negative rod bacteremia after cardiovascular surgery: Clinical features and prognostic factors.

BACKGROUND/PURPOSE: Our aim was to describe the clinical features and prognostic factors of Gram-negative rod bacteremia (GNRB) after cardiovascular surgery (CVS). METHODS: This retrospective observational study included adults with GNRB onset within 100 days after CVS at a single institution from April 2004 to May 2013. Clinical data regarding episodes of GNRB were collected from patients' medical charts. Those having polymicrobial bacteremia with a bacterium other than a GNR were excluded. RESULTS: Among 2017 CVS patients, GNRB occurred in 78. Klebsiella, Pseudomonas aeruginosa, Enterobacter, and Escherichia coli were the most commonly isolated organisms. Graft replacement was the most common surgical procedure in patients with GNRB after CVS (44.9%). Prophylaxis antibiotics were ampicillin/sulbactam (76.9%), and vancomycin (12.8%). The crude 90-day mortality rate was 21.8%, and the mean Acute Physiology and Chronic Health Evaluation II score was 15.6 (range, 3-39). In 34.6% of patients, the same GNR species were isolated from other samples within 30 days of GNRB occurrence. Multivariate analysis indicated that P. aeruginosa bacteremia [odds ratio (OR), 175; confidence interval (CI), 2.40-1270; p = 0.0182], Acute Physiology and Chronic Health Evaluation II scores of ≥ 25 (OR 76.2; CI 1.04-5580; p = 0.0479), and vancomycin for prophylaxis (OR 45.4; CI 1.02-202; p = 0.0488) were significant independent prognostic factors associated with death due to GNRB after CVS. CONCLUSION: Graft replacement was the most common surgical procedure in patients with GNRB after CVS. Empirical antibiotics covering Gram-negative rods including P. aeruginosa should be considered if bacteremia is suspected in unstable patients after CVS.

Complete genome sequence of Rhizobium leguminosarum bv trifolii strain WSM2304, an effective microsymbiont of the South American clover Trifolium polymorphum.

Rhizobium leguminosarum bv trifolii is the effective nitrogen fixing microsymbiont of a diverse range of annual and perennial Trifolium (clover) species. Strain WSM2304 is an aerobic, motile, non-spore forming, Gram-negative rod, isolated from Trifolium polymorphum in Uruguay in 1998. This microsymbiont predominated in the perennial grasslands of Glencoe Research Station, in Uruguay, to competitively nodulate its host, and fix atmospheric nitrogen. Here we describe the basic features of WSM2304, together with the complete genome sequence, and annotation. This is the first completed genome sequence for a nitrogen fixing microsymbiont of a clover species from the American center of origin. We reveal that its genome size is 6,872,702 bp encoding 6,643 protein-coding genes and 62 RNA only encoding genes. This multipartite genome was found to contain 5 distinct replicons; a chromosome of size 4,537,948 bp and four circular plasmids of size 1,266,105 bp, 501,946 bp, 308,747 bp and 257,956 bp.

Complete genome sequence of the Medicago microsymbiont Ensifer (Sinorhizobium) medicae strain WSM419.

Ensifer (Sinorhizobium) medicae is an effective nitrogen fixing microsymbiont of a diverse range of annual Medicago (medic) species. Strain WSM419 is an aerobic, motile, non-spore forming, Gram-negative rod isolated from a M. murex root nodule collected in Sardinia, Italy in 1981. WSM419 was manufactured commercially in Australia as an inoculant for annual medics during 1985 to 1993 due to its nitrogen fixation, saprophytic competence and acid tolerance properties. Here we describe the basic features of this organism, together with the complete genome sequence, and annotation. This is the first report of a complete genome sequence for a microsymbiont of the group of annual medic species adapted to acid soils. We reveal that its genome size is 6,817,576 bp encoding 6,518 protein-coding genes and 81 RNA only encoding genes. The genome contains a chromosome of size 3,781,904 bp and 3 plasmids of size 1,570,951 bp, 1,245,408 bp and 219,313 bp. The smallest plasmid is a feature unique to this medic microsymbiont.