High mortality associated with inappropriate initial antibiotic therapy in hematological malignancies with Klebsiella pneumoniae bloodstream infections.

Bloodstream infections caused by multidrug-resistant organisms such as Klebsiella pneumoniae are a significant challenge in managing hematological malignancies. This study aims to characterize the epidemiology of Klebsiella pneumoniae bloodstream infections specifically in patients with hematological malignancies, delineate the patterns of initial antibiotic therapy, assess the prevalence of resistant strains, identify risk factors for these resistant strains, and evaluate factors influencing patient outcomes. A retrospective analysis was conducted at a single center from January 2017 to December 2020, focusing on 182 patients with hematological malignancies who developed Klebsiella pneumoniae bloodstream infections. We compared the 30-day mortality rates between patients receiving appropriate and inappropriate antibiotic treatments, including the effectiveness of both single-drug and combination therapies. Kaplan-Meier survival analysis and multivariate logistic and Cox regression were used to identify factors influencing mortality risk. The 30-day all-cause mortality rate was 30.2% for all patients. The 30-day all-cause mortality rates were 77.2% and 8.8% in patients who received inappropriate initial treatment and appropriate initial treatment (p < 0.001). Inappropriate initial treatment significantly influenced mortality and was a key predictor of 30-day mortality, along with septic shock and previous intensive care unit (ICU) stays. Patients with carbapenem-resistant Klebsiella pneumoniae (CRKP) bloodstream infections exhibited more severe clinical symptoms compared to the CSKP group. The study demonstrates a significant association between empirical carbapenem administration and the escalating prevalence of CRKP and multidrug-resistant K. pneumoniae (MDR-KP) infections. Furthermore, the study identified inappropriate initial antibiotic therapy, septic shock, and ICU admission as independent risk factors for 30-day mortality.

Should we review our prophylaxis approach for increased antibiotic resistance in transrectal prostate biopsy?

INTRODUCTION: This study aims to show the bacteriologic picture of acute prostatitis and bacteremia caused by infective agent after transrectal ultrasound-guided prostate biopsy (TRUSBx) and to determine the resistance rates of the infections in patients undergoing transrectal biopsy and to guide prophylaxis approach before biopsy. METHODOLOGY: The retrospective data of 935 patients who underwent TRUSBx between January 2010 to January 2019 were reviewed. Pre-biopsy urine cultures and antimicrobial susceptibility were obtained. Subsequently, patients admitted to the hospital with any complaint after biopsy were examined for severe infection complications. RESULTS: Of the 430 (61.7%) patients who underwent urine culture before the procedure, 45 (10.5%) had growth; 30 (66.7%) of the growing microorganisms were Escherichia coli. Twenty (44.4%) of all Gram-negative agents in pre-biopsy urine culture were susceptible to quinolone. Post TRUSBx bacteremia was present in 18.2%, urinary system infection in 83.6%, and hospitalization in 61.8% of 55 patients who were admitted to the hospital. In the isolated gram-negative microorganisms, fluoroquinolones resistance in urinary system infections was seen in 40% and bacteremia was seen in 70% of the cases. ESBL-producing Gram-negative bacteria were determined in 40% of infections in blood and 38.5% of urinary system infections in the post biopsy period in the current study. CONCLUSIONS: These high antibiotic resistance rates suggest that we better review our pre-procedure prophylaxis approaches.

[Microorganisms isolated from blood cultures and resistance profile in children with cancer and high-risk febrile neutropenia. Red PINDA, Chile, 2016-2021]. / Microorganismos aislados de hemocultivos y su perfil de resistencia en niños con cáncer y neutropenia febril de alto riesgo. Red PINDA, Chile, 2016-2021.

Bacteremia is a major cause of morbidity and mortality in patients with cancer and episodes of high-risk febrile neutropenia (HRFN). OBJECTIVE: To identify the frequency of microorganisms isolated from blood cultures (BC) and their antimicrobial resistance (R) profile in children with HRFN, compared with the same data from previous studies of the same group. METHOD: Prospective, multicenter, epidemiological surveillance study of microorganisms isolated from BC in patients under 18 years of age, from 7 PINDA network hospitals, between 2016 and 2021. RESULTS: 284 episodes of HRFN with positive BC were analyzed out of 1091 enrolled episodes (26%). Median age 7.2 years [3.0-12.3]. The main isolates were gram-negative bacilli (GNB) 49.2%, gram-positive cocci (GPC) 43.8%, and fungi 3.6%. The most frequently isolated microorganisms were viridans group Streptococci (VGS) (25.8%), Escherichia coli (19.8%), Pseudomonas spp. (11.2%), Klebsiella spp. (10.9%), and coagulase negative Staphylococci (CoNS) (10.9%). There was an increase in R to third-generation cephalosporins (p = 0.011) in GNB and to oxacillin in CoNS (p = 0.00), as well as a decrease in R to amikacin in non-fermenting GNB (p = 0.02) and to penicillin in VGS (p = 0.04). CONCLUSION: VGS is the main agent isolated in BC from pediatric patients with cancer and episodes of HRFN, followed by E. coli, Pseudomonas spp., and Klebsiella spp. Having epidemiological surveillance of microorganisms isolated from BC and their antimicrobial R profile is essential to favor the rational use of antimicrobials.

An evaluation of a Stenotrophomonas maltophilia outbreak due to commercial arterial blood gas collection kit.

BACKGROUND: Stenotrophomonas maltophilia is a gram-negative bacterium that can cause hospital infections and outbreaks within hospitals. This study aimed to evaluate an outbreak of Stenotrophomonas maltophilia, caused by ready-to-use commercial syringes containing liquid lithium and heparin for arterial blood gas collection in a university hospital. METHODS: Upon detecting an increase in Stenotrophomonas maltophilia growth in blood cultures between 15.09.2021 and 19.11.2021, an outbreak analysis and a case-control study (52 patients for the case group, 56 patients for the control group) were performed considering risk factors for bacteremia. Samples from possible foci for bacteremia were also cultured. Growing bacteria were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The genetic linkage and clonal relationship isolates were investigated with pulsed-field gel electrophoresis (PFGE) in the reference laboratory. RESULTS: In the case-control study, the odds ratio for the central venous catheter [3.38 (95% confidence interval [CI]: 1.444, 8.705 ; p = 0.006)], for surgery [3.387 (95% confidence interval [CI]: 1.370, 8.373 ; p = 0.008)] and for arterial blood gas collection history [18.584 (95% confidence interval [CI]:4.086, 84.197; p < 0.001)] were identified as significant risk factors. Stenotrophomonas maltophilia growth was found in ready-to-use commercial syringes used for arterial blood gas collection. Molecular analysis showed that the growths in the samples taken from commercial syringes and the growths from blood cultures were the same. It was decided that the epidemic occurred because the method for sterilization of heparinized liquid preparations were not suitable. After discontinuing the use of the kits with this lot number, the outbreak was brought under control. CONCLUSIONS: According to our results, disposable or sterile medical equipment should be included as a risk factor in outbreak analyses. The method by which injectors containing liquids, such as heparin, are sterilized should be reviewed. Our study also revealed the importance of the cooperation of the infection control team with the microbiology laboratory.

Do oral conditions influence the incidence of bloodstream infection after hematopoietic stem cell transplantation? A retrospective study in Japan.

PURPOSE: This study aimed to evaluate the incidence of bloodstream infection (BSI) among patients undergoing hematopoietic stem cell transplantation (HSCT) for teeth indicated for extraction. METHODS: Patients who underwent HSCT at Toranomon Hospital (Tokyo, Japan) between January 2017 and December 2019 were retrospectively evaluated. The incidence of BSI among patients with teeth indicated for extraction who did not undergo extraction (oral high-risk group) and patients who did not have this risk (oral low-risk group) was compared. RESULTS: Among the 191 consecutive patients included in this study, 119 patients were classified as undergoing high-risk transplantation. BSI after HSCT was observed in 32 out of 60 (53.3%) patients and 56 out of 131 (42.7%) patients in the oral low-risk and oral high-risk groups, respectively (p = 0.173). Multivariable analyses revealed that the presence of > 3 teeth as intraoral sources of infection and age over 50 years were determinants of BSI originating from the oral cavity after engraftment (odds ratio [OR], 9.11; 95% confidential interval [CI] 2.27-36.61]; p = 0.002; OR, 3.22; CI [1.47-7.08], p = 0.004, respectively). CONCLUSION: In patients undergoing HSCT, the presence of less than three intraoral sources of infection did not affect the incidence of BSI after HSCT.

A Case of Bacteremia Caused by Raoultella planticola Direct Identification from Blood Culture by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry.

Background: Raoultella planticola is an uncommon gram-negative organism found in the environment. Patients and Methods: The patient, an 81-year-old female who had undergone total cystectomy and bilateral ureteral stoma surgery, presented to the hospital with a fever. It was determined that Raoultella planticola was responsible for the bacteremia. Results: Rapid identification of bacteria using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) in blood culture samples and appropriate antibacterial treatment was begun and the patient was discharged three days later. Conclusions: This case emphasizes the presence of a rare pathogen as the cause of bacteremia and underscores the importance of utilizing rapid methods for bacterial identification to establish an accurate diagnosis.

[Key microbial monitoring and clinical analysis of bloodstream infections and CRO colonization after hematopoietic stem cell transplantation in hematological patients].

Objective: To investigate the distribution and clinical characteristics of pathogenic bacteria following hematopoietic stem cell transplantation (HSCT), as well as to provide a preliminary research foundation for key microbial monitoring, and clinical diagnosis and treatment of infections after HSCT in hematological patients. Methods: We retrospectively analyzed the clinical data of 190 patients who tested positive for microbial testing [G-bacteria blood culture and/or carbapenem-resistant organism (CRO) screening of perianal swabs] at our center from January 2018 to December 2022. Patients were divided into blood culture positive, perianal swab positive, and double positive groups based on the testing results. The three patient groups underwent statistical analysis and comparison. Results: The top four pathogenic bacteria isolated from sixty-three patients with G-bacteria bloodstream infection (BSI) were Escherichia coli (28 strains, 43.75% ), Klebsiella pneumonia (26 strains, 40.63% ), Pseudomonas aeruginosa (3 strains, 4.69% ), and Enterobacter cloacae (3 strains, 4.69% ). The top three pathogenic bacteria isolated from 147 patients with CRO perianal colonization were carbapenem-resistant Klebsiella pneumoniae (58 strains, 32.58% ), carbapenem-resistant Escherichia coli (49 strains, 27.53% ), and carbapenem-resistant Enterobacter cloacae (20 strains, 11.24% ). The 3-year disease-free survival (DFS ) and overall survival (OS) of double positive group patients were significantly lower compared to those in the blood culture and perianal swab positive groups (DFS: 35.6% vs 53.7% vs 68.6%, P=0.001; OS: 44.4% vs 62.4% vs 76.9%, P<0.001), while non-relapse mortality (NRM) was significantly higher (50.0% vs 34.9% vs 10.6%, P<0.001). Failed engraftment of platelets and BSI are independent risk factors for NRM (P<0.001). Using polymyxin and/or ceftazidime-avibactam for more than 7 days is an independent protective factor for NRM (P=0.035) . Conclusion: This study suggests that the occurrence of BSI significantly increases the NRM after HSCT in patients with hematological diseases; CRO colonization into the bloodstream has a significant impact on the DFS and OS of HSCT patients.

Pseudomonas fluorescens CRBSI outbreak: complying with the standardization of invasive procedures is a step ahead in the fight against antimicrobial resistance.

In the healthcare sector, the implementation of standardized procedures, such as those commonly employed in franchises to ensure consistent quality, remains underprioritized. Within this framework, we focus on the importance of standardized central venous catheter (CVC) insertion procedures to prevent healthcare-associated outbreaks. While antimicrobial resistance (AMR) may still not be the most prevalent problem in some institutions, its increasing significance certainly underlines the urgency of infection prevention.We aim to highlight this issue by describing and discussing an outbreak scenario of carbapenem-resistant (CR) Pseudomonas fluorescens bloodstream infections resulting from a deviation from the standardized CVC insertion procedure. This outbreak led to six episodes of catheter related bloodstream infection (CRBSI) in patients with hematologic malignancies, delaying their primary treatment. Nineteen patients were exposed, leading to an attack rate of 31.6%.

A Rare Cause of Empyema and Bacteremia Due to Shewanella Species in Alcoholic Cirrhosis Patients: A Case Report and Comprehensive Review of Literature.

BACKGROUND Shewanella spp. are gram-negative facultative anaerobic, oxidase-positive, motile bacilli that are ubiquitous but commonly occur in seawater and can cause opportunistic infection. Reports on the risk factors for Shewanella infection, its severity, antibiotic susceptibility, and prognosis are limited. This report is of a 78-year-old man with alcoholic cirrhosis presenting with bacteremia and empyema due to infection with Shewanella spp. CASE REPORT A 78-year-old man with alcoholic cirrhosis (Child-Pugh B) presented to our emergency room with a high fever. He had eaten raw fish one week prior to admission. Chest computed tomography showed a right unilateral pleural effusion, and he was hospitalized with suspected empyema. Shewanella spp. was detected in the pleural effusion and blood cultures. We initiated piperacillin/tazobactam and vancomycin empirically and switched to ceftriaxone; the effusion was successfully treated using antibiotics and pleural drainage. However, on hospitalization day 53, the patient died of aspiration pneumonia. In our literature review, we extracted 125 reported cases (including our case) and found that men were disproportionately affected (81%); median age was 61.6 (56-75) years; underlying diseases included hepatobiliary disease (33%), malignancy (25%), and cardiac disease (24%); Shewanella spp. infection sites were skin and soft tissue (35%), respiratory system (18%), and hepatobiliary system (11%); and management included antibiotics (100%), drainage (16%), and debridement (16%). The survival rate was 74% with antibiotics alone. CONCLUSIONS Our case highlights that clinicians should recognize Shewanella spp. as a cause of empyema and bacteremia in patients with liver cirrhosis, and that microbiological diagnosis with antibiotic sensitivity testing and treatment should be undertaken urgently to prevent fatal sepsis.

[Distribution and Drug Resistance of Pathogens Causing Bloodstream Infection in Patients with Hematological Malignancies].

OBJECTIVE: To investigate distribution and drug resistance of pathogens of bloodstream infection in patients with hematological malignancies, in order to provide reference for clinical infection control and treatment. METHODS: The clinical information of blood culture patients in the hematology department of our hospital from January 2016 to December 2021 was reviewed. They were divided into transplantation group and non-transplantation group according to whether they had undergone hematopoietic stem cell transplantation. The types of pathogens and their drug resistance were analyzed. RESULTS: Two hundred and ninety-nine positive strains of pathogenic bacteria were detected. In the transplantation group, Gram-negative bacteria accounted for 68.5% (50/73), Gram-positive bacteria accounted for 6.8% (5/73), and fungi accounted for 24.7% (18/73). The resistance rate of Escherichia coli to the third-generation cephalosporins was 77.8%, and 11.5% to carbapenems. The resistance rate of Klebsiella pneumoniae to the third-generation cephalosporins was 50.0%, and 56.2% to carbapenems. In the non-transplantation group, Gram-negative bacteria accounted for 64.1% (145/226), Gram-positive bacteria accounted for 31.0% (70/226), and fungi accounted for 4.9% (11/226). Gram-positive bacteria were mainly Enterococcus faecium (6.6%, 15/226) and Coagulase-negative Staphylococci (6.2%, 14/226). The fungi were all Candida tropicalis. The resistance rate of Escherichia coli to the third-generation cephalosporins was 63.8%, and 10.3% to carbapenems. The resistance rate of Klebsiella pneumoniae to the third-generation cephalosporins was 46.3%, and 26.8% to carbapenems. CONCLUSION: The types of pathogenic bacteria in bloodstream infection in patients with hematological malignancies are varied. Gram-negative bacteria is the main pathogenic bacteria. The resistance of pathogenic bacteria to antibiotics is severe. Antibiotics should be used scientifically and reasonably according to the detection and resistance of pathogenic bacteria.

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.

Preterm infant with necrotizing enterocolitis and arteritis secondary to streptococcus gallolyticus subspecies pasteurianus.

 Streptococcus gallolyticus subspecies pasteurianus is a subtype of Streptococcus bovis (S. bovis) that has become increasingly recognized as a sepsis-causing pathogen in neonates. It is well documented that S. bovis species have a predilection to both cardiac and gastrointestinal tissue, and in adult populations, isolating these organisms in the bloodstream often triggers further evaluation for co-morbid complications such as colon cancer or endocarditis. However, no such guidance currently exists in neonatal literature. We present a case of a preterm infant with S. gallolyticus subsp. pasteurianus bacteremia presenting as necrotizing enterocolitis (NEC) not previously described in the literature. Furthermore, through a complete diagnostic evaluation, including an echocardiogram, our patient was found to have the rare complication of endocarditis.

Comparative epidemiology of bacteraemia in two ageing populations: Singapore and Denmark.

Burden of bacteraemia is rising due to increased average life expectancy in developed countries. This study aimed to compare the epidemiology and outcomes of bacteraemia in two similarly ageing populations with different ethnicities in Singapore and Denmark. Historical cohorts from the second largest acute-care hospital in Singapore and in the hospitals of two Danish regions included patients aged 15 and above who were admitted from 1 January 2006 to 31 December 2016 with at least 1 day of hospital stay and a pathogenic organism identified. Among 13 144 and 39 073 bacteraemia patients from Singapore and Denmark, similar 30-day mortality rates (16.5%; 20.3%), length of hospital stay (median 14 (IQR: 9-28) days; 11 (6-21)), and admission rate to ICU (15.5%; 15.6%) were observed, respectively. Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus ranked among the top four in both countries. However, Singaporeans had a higher proportion of patients with diabetes (46.8%) and renal disease (29.5%) than the Danes (28.0% and 13.7%, respectively), whilst the Danes had a higher proportion of patients with chronic pulmonary disease (18.0%) and malignancy (35.3%) than Singaporeans (9.7% and 16.2%, respectively). Our study showed that top four causative organisms and clinical outcomes were similar between the two cohorts despite pre-existing comorbidities differed.

Risk factors for bacteremic pneumonia and mortality (28-day mortality) in patients with Acinetobacter baumannii bacteremia.

BACKGROUND: Patients infected with Acinetobacter baumannii (AB) bacteremia in hospital have high morbidity and mortality. We analyzed the clinical characteristics of pneumonia and nonpneumonia-related AB bloodstream infections (AB BSIs) and explored the possible independent risk factors for the incidence and prognosis of pneumonia-related AB BSIs. METHODS: A retrospective monocentric observational study was performed. All 117 episodes of hospital-acquired AB bacteremia sorted into groups of pneumonia-related AB BSIs (n = 45) and nonpneumonia-related AB BSIs (n = 72) were eligible. Univariate/multivariate logistic regression analysis was used to explore the independent risk factors. The primary outcome was the antibiotic susceptibility in vitro of pneumonia-related AB BSIs group. The secondary outcome was the independent risk factor for the pneumonia-related AB BSIs group. RESULTS: Among 117 patients with AB BSIs, the pneumonia-related group had a greater risk of multidrug resistant A. baumannii (MDRAB) infection (84.44%) and carbapenem-resistant A. baumannii (CRAB) infection (80%). Polymyxin, minocycline and amikacin had relatively high susceptibility rates (> 80%) in the nonpneumonia-related group. However, in the pneumonia-related group, only polymyxin had a drug susceptibility rate of over 80%. Univariate analysis showed that survival time (day), CRAB, MDRAB, length of hospital stay prior to culture, length of ICU stay prior to culture, immunocompromised status, antibiotics used prior to culture (n > = 3 types), endotracheal tube, fiberoptic bronchoscopy, PITT, SOFA and invasive interventions (n > = 3 types) were associated with pneumonia-related AB bacteremia. The multivariate logistic regression analysis revealed that recent surgery (within 1 mo) [P = 0.043; 0.306 (0.098-0.962)] and invasive interventions (n > = 3 types) [P = 0.021; 0.072 (0.008-0.671)] were independent risk factors related to pneumonia-related AB bacteremia. Multivariate logistic regression analysis revealed that length of ICU stay prior to culture [P = 0.009; 0.959 (0.930-0.990)] and recent surgery (within 1 mo) [P = 0.004; 0.260 (0.105-0.646)] were independent risk factors for mortality in patients with pneumonia-related AB bacteremia. The Kaplan‒Meier curve and the timing test showed that patients with pneumonia-related AB bacteremia had shorter survival time compared to those with nonpneumonia-related AB bacteremia. CONCLUSIONS: Our study found that A. baumannii had a high rate of antibiotic resistance in vitro in the pneumonia-related bacteremia group, and was only sensitive to polymyxin. Recent surgery was a significantly independent predictor in patients with pneumonia-related AB bacteremia.

Results of a long-term, prospective study on complications of central venous catheter in pediatric patients with hematologic-oncologic diseases.

BACKGROUND: Central venous catheter (CVC)-related complications remain a significant cause of morbidity in pediatric hematology-oncology. We prospectively surveyed the incidence of CVC-related complications in children with hematologic-oncologic diseases. PROCEDURE: Five-hundred-eighty-one CVCs were inserted in 421 patients from January 2010 to June 2022 (153,731 CVC days observation; follow-up data up to December 31, 2022). RESULTS: Overall, 671 complications were recorded (4.365/1000 CVC days): 49.7% malfunctions (1.88/1000 CVC days, 4.8% of CVC early removals), 23.9% bacteremia (0.90/1000, 15.1%), 19.6% mechanical complications (0.74/1000, 70.2%), 20.1% localized infections (0.76/1000, 17.1%), 0.5% thrombosis (0.02/1000, 33.3%). At multivariate analysis, risk factors for malfunction were Broviac-Hickman type of CVC (hazard ratio [HR] 2.5) or Port-a-cath (HR 3.4) or Proline (HR 4.3), p < .0001; for bacteremia double-lumen CVC (HR 3.2, p < .0001); for mechanical complications age at CVC insertion under median (HR 4.5, p < .0001) and Broviac-Hickman (HR 1.6) or Proline (HR 2.7), p = .01; finally for localized infections Broviac-Hickman (HR 2.9) or Proline (HR 4.4), p = .0001. The 2-year cumulative incidence of premature removal was 23.5%, and risk factors were age at CVC insertion under median (HR 2.4, p < .0001), Broviac-Hickman (HR 2.3) or Proline (HR 4.2), p < .0001. CONCLUSIONS: Premature removal occurs in approximately 20%-25% of long-term CVCs. A surveillance program has a fundamental role in identifying the risk factors for CVC complications and the areas of intervention to improve CVC management.

Short versus prolonged duration of therapy for Pseudomonas aeruginosa bacteraemia: a systematic review and meta-analysis.

The optimal duration of therapy for Pseudomonas aeruginosa bloodstream infection (PSA-BSI) is unknown, with prolonged therapy frequently favored due to severity of infection, patient complexity, risk of multi-drug resistance, and high mortality. We therefore conducted a systematic review and meta-analysis of studies with head-to-head comparison of short versus prolonged therapy for PSA-BSI. A comprehensive search including Ovid MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Scopus was performed. We pooled risk ratios using DerSimonian-Laird random effects model and performed subgroup analysis of outcomes including all-cause mortality, recurrent infection, and composite of these outcomes among patients receiving short versus prolonged therapy for PSA-BSI. Heterogeneity was assessed by the I2-index. Risk of bias for cohort studies was assessed using ROBINS-I tool. Of the 908 identified studies, six were included in the systematic review and five studies with head-to-head comparison of treatment duration were assessed in the meta-analysis, totalling 1746 patients. No significant difference in propensity score-weighted composite outcome (30-day all-cause mortality or recurrent infection) was noted between patients receiving short or prolonged therapy, with a pooled RR risk ratio of 0.80 (95% CI confidence interval 0.51-1.25, P=0.32; I2 = 0%). Additionally, duration of therapy did not impact individual outcomes of 30-day all-cause mortality or recurrent/persistent infection. Our meta-analysis demonstrated that short duration of antimicrobial therapy may have similar efficacy to prolonged treatment for PSA-BSI. Future randomized trials will be necessary to definitively determine optimal management of PSA bacteraemia.

Comparative analysis of the antimicrobial resistance and virulence traits in ESBL-producing-Klebsiella pneumoniae ST307 strains colonizing the gastrointestinal tract and causing a fatal bloodstream infection in a leukemia patient.

Klebsiella pneumoniae is an opportunistic pathogen that can colonize the gastrointestinal tract (GIT) of humans. The mechanisms underlying the successful translocation of this pathogen to cause extra-intestinal infections remain unknown, although virulence and antimicrobial resistance traits likely play significant roles in the establishment of infections. We investigated K. pneumoniae strains isolated from GIT colonization (strains Kp_FZcol-1, Kp_FZcol-2 and Kp_FZcro-1) and from a fatal bloodstream infection (strain Kp_HM-1) in a leukemia patient. All strains belonged to ST307, carried a transferable IncF plasmid containing the blaCTX-M-15 gene (pKPN3-307 TypeA-like plasmid) and showed a multidrug-resistance phenotype. Phylogenetic analysis demonstrated that Kp_HM-1 was more closely related to Kp_FZcro-1 than to the other colonizing strains. The Kp_FZcol-2 genome showed 81 % coverage with the Kp_HM-1 246,730 bp plasmid (pKp_HM-1), lacking most of its putative virulence genes. Searching public genomes with similar coverage, we observed the occurrence of this deletion in K. pneumoniae ST307 strains recovered from human colonization and infection in different countries. Our findings suggest that strains lacking the putative virulence genes found in the pKPN3-307 TypeA plasmid are still able to colonize and infect humans, highlighting the need to further investigate the role of these genes for the adaptation of K. pneumoniae ST307 in distinct human body sites.

Pasteurella multocida activates apoptosis via the FAK-AKT-FOXO1 axis to cause pulmonary integrity loss, bacteremia, and eventually a cytokine storm.

Pasteurella multocida is an important zoonotic respiratory pathogen capable of infecting a diverse range of hosts, including humans, farm animals, and wild animals. However, the precise mechanisms by which P. multocida compromises the pulmonary integrity of mammals and subsequently induces systemic infection remain largely unexplored. In this study, based on mouse and rabbit models, we found that P. multocida causes not only lung damage but also bacteremia due to the loss of lung integrity. Furthermore, we demonstrated that bacteremia is an important aspect of P. multocida pathogenesis, as evidenced by the observed multiorgan damage and systemic inflammation, and ultimately found that this systemic infection leads to a cytokine storm that can be mitigated by IL-6-neutralizing antibodies. As a result, we divided the pathogenesis of P. multocida into two phases: the pulmonary infection phase and the systemic infection phase. Based on unbiased RNA-seq data, we discovered that P. multocida-induced apoptosis leads to the loss of pulmonary epithelial integrity. These findings have been validated in both TC-1 murine lung epithelial cells and the lungs of model mice. Conversely, the administration of Ac-DEVD-CHO, an apoptosis inhibitor, effectively restored pulmonary epithelial integrity, significantly mitigated lung damage, inhibited bacteremia, attenuated the cytokine storm, and reduced mortality in mouse models. At the molecular level, we demonstrated that the FAK-AKT-FOXO1 axis is involved in P. multocida-induced lung epithelial cell apoptosis in both cells and animals. Thus, our research provides crucial information with regard to the pathogenesis of P. multocida as well as potential treatment options for this and other respiratory bacterial diseases.

Proteus species bloodstream infections: Comparative epidemiology of three species.

BACKGROUND: Although Proteus species are occasional causes of serious infections, their epidemiology has not been well defined. The objective was to describe the overall and species-specific occurrence and determinants of Proteus species bloodstream infection (BSI) in a large Australian population. METHODS: All Queensland residents with Proteus species BSI identified within the publicly funded healthcare system between 2000 and 2019 were included. RESULTS: A total of 2,143 incident episodes of Proteus species BSI were identified among 2,079 Queensland residents. The prevalence of comorbid illness differed with higher Charlson comorbidity scores observed with P. penneri and P. vulgaris, and higher prevalence of liver disease with P. penneri, higher comorbid cancer with P. vulgaris, and lower diabetes and renal disease prevalence with P. mirabilis BSIs. CONCLUSION: This study provides novel information on the epidemiology of Proteus species BSI.