[Analysis of Pathogenic Bacterial Spectrum, Drug Resistance and Risk Factors for Mortality of Bloodstream Infection in Patients with Hematologic Diseases]

OBJECTIVE

To analyze the pathogenic bacterial spectrum, drug resistance, and risk factors associated with multidrug-resistant bacterial infection and mortality in patients with hematologic diseases complicated by bloodstream infections, so as to provide reference for rational drug use and improving prognosis.

METHODS

Positive blood culture specimens of patients with hematologic diseases in two Class A tertiary hospitals of Shanxi province from January 2019 to December 2021 were retrospectively analyzed. Pathogen distribution, drug resistance and outcomes of patients with bloodstream infection were investigated, then the multivariate logistic analysis was performed to analyze the risk factors of multidrug-resistant bacterial infection and factors affecting prognosis.

RESULTS

203 strains of pathogens were identified, mainly Gram-negative bacteria (GNB) (69.46%, 141/203), of which Escherichia coli (E.coli) had the highest incidence (41.13%, 58/141), followed by Klebsiella pneumoniae (20.57%, 29/141) and Pseudomonas aeruginosa (12.77%, 18/141). Extended-spectrum beta-lactamase (ESBL)-producing E.coli and Klebsiella pneumoniae were 46.55% (27/58) and 37.93% (11/29), respectively. Carbapenem-resistant Gram-negative bacteria accounted for 10.64% (15/141). And Gram-positive bacteria accounted for 27.59% (56/203), Staphylococcus epidermidis, Streptococcus pneumoniae, and Staphylococcus aureus were the most frequently isolated pathogen among Gram-positive bacteria (14.29%, 12.50% and 10.71%, respectively), of which methicillin-resistant Staphylococcus aureus accounted for 33.33% (2/6), coagulase-negative staphylococci accounted for 87.50% (7/8), without vancomycin- or linezolid-resistant strain. Additionally, fungi accounted for 2.95% (6/203), all of which were Candida. Multidrug-resistant Gram-negative bacteria (MDR-GNB) accounted for 53.90% (76/141). Duration of neutropenia >14 days was a risk factor for developing MDR-GNB infection. The 30-day all-cause mortality was 10.84%. Multivariate logistic regression analysis showed that the significant independent risk factors for mortality were age≥60 years (P <0.01, OR =5.85, 95% CI: 1.80-19.07) and use of vasopressor drugs (P <0.01, OR =5.89, 95% CI: 1.83-18.94).

CONCLUSION

The pathogenic bacteria of bloodstream infection in patients with hematological diseases are widely distributed, and the detection rate of multidrug-resistant bacteria is high. The clinicians should choose suitable antibiotics according to the results of bacterial culture and antibiotic susceptibility test.

[Analysis of Clinical Features and Risk Factors for Oral Ulcers and Bloodstream Infection in Patients with Hematopoietic Stem Cell Transplantation]

OBJECTIVE

To investigate the risk factors of oral ulcers and bloodstream infection in patients with hematopoietic stem cell transplantation.

METHODS

The clinical data of 401 hematopoietic stem cell transplant patients in the First Affiliated Hospital of Zhengzhou University from January 2020 to December 2021 were retrospective analyzed, and the risk factors of oral ulcers and bloodstream infection statistical and analyzed.

RESULTS

Among the 401 patients, the incidence of oral ulcers was 61.3% (246/401), and the incidence of bloodstream infection was 9.0% (36/401). A total of 40 strains of pathogenic bacteria were isolated from 36 patients, including 26 strains of Gram negative strains (65%), 13 strains of Gram positive strains (32.5%), and 1 strain of fungi (2.5%). Single-factor analysis showed that oral hygiene was associated with the occurrence of bloodstream infection, and the Multi-factor analysis showed that age ≥14 years old, disease diagnosis of leukemia, and allogeneic hematopoietic stem cell transplantation were risk factors for oral ulcers.

CONCLUSION

The incidence of oral ulcers in patients with hematopoietic stem cell transplantation is high. The age ≥14 years, disease diagnosis of leukemia, and allogeneic hematopoietic stem cell transplantation were risk factors for oral ulcers in patients, and oral hygiene was associated with the occurrence of bloodstream infection.

[Single Center Clinical Analysis of Bloodstream Infection Pathogens in Children with Acute Leukemia]

OBJECTIVE

To investigate the clinical features, distribution of pathogenic bacteria, and drug resistance of bloodstream infection in children with acute leukemia.

METHODS

Clinical data of 93 blood culture-positive children with acute leukemia from January 2015 to December 2019 in Department of Pediatrics, The Second Hospital of Anhui Medical University were analyzed retrospectively.

RESULTS

In these 93 cases, 78 cases were in the period of neutrophil deficiency. There were 54 Gram-negative bacteria (G^-) (58.1%) found through blood culture, and the top 4 strains were Escherichia coli (15.1%), Klebsiella pneumoniae (13.9%), Pseudomonas aeruginosa (6.5%), and Enterobacter cloacae (6.5%). There were 39 Gram-positive bacteria (G⁺) (41.9%) detected, and the top 4 strains were Staphylococcus epidermidis (10.8%), Streptococcus pneumoniae (6.5%), Staphylococcus hemolyticus (5.4%), and Staphylococcus human (5.4%). Among 74 strains of pathogenic bacteria from acute lymphoblastic leukemia (ALL) children, there were 29 strains of G⁺ bacteria (39.2%) and 45 strains of G^- bacteria (60.8%). While in 19 strains from acute myeloblastic leukemia (AML) patients, G^- bacteria accounted for 47.4% and G⁺ bacteria accounted for 52.6%. In 15 ALL children without neutropenia, G⁺ bacteria made up the majority of the strains (66.7%). In the 93 strains of pathogenic bacteria, 13 (13.9%) strains were multidrug-resistant. Among them, extended-spectrum β-lactamases accounted for 42.9%, carbapenemase-resistant enzyme Klebsiella pneumoniae 15.4%, and carbapenemase-resistant enzyme Enterobacter cloacae strains 33.3%, which were detected from G^- bacteria. While, 13.3% of methicillin-resistant coagulase-negative Staphylococci accounted for 13.3% detected from G⁺ bacteria, but linezolid, vancomycin, teicoplanin Staphylococcus and Enterococcus resistant were not found. The average procalcitonin (PCT) value of G^- bacteria infection was (11.02±20.282) ng/ml, while in G⁺ infection it was (1.81±4.911) ng/ml, the difference was statistically significant (P<0.05). The mean value of C-reactive protein (CRP) in G^- infection was (76.33±69.946) mg/L, and that in G⁺ infection was (38.34±57.951) mg/L. The prognosis of active treatment was good, and only one case died of septic shock complicated with disseminated intravascular coagulation (DIC) and gastrointestinal bleeding caused by carbapenemase-resistant enzyme enterobacteriaceae.

CONCLUSION

G^- is the major bacteria in acute leukemia children with bloodstream infection, but the distribution of ALL and AML strains is different. G^- bacteria dominates in ALL, while G⁺ bacteria and G^- bacteria are equally distributed in AML. Non-agranulocytosis accompanied by bloodstream infections is dominant by G⁺ bacteria. The mean value of PCT and CRP are significantly higher in G^- bacteria infection than in G⁺ bacteria.

[Clinical Analysis of Bloodstream Infection after Hematopoietic Stem Cell Transplantation]

OBJECTIVE

To analyze the clinical characteristics of bloodstream infection (BSI) in patients treated by hematopoietic stem cell transplantation (HSCT).

METHODS

The clinical characteristics, distribution of pathogenic bacteria causing BSI and drug sensitivity of 910 patients treated by HSCT in our department from January 2013 to June 2020 were retrospectively analyzed.

RESULTS

Among 910 HSCT patients, 111 patients were diagnosed as BSI within 100 days after transplantation, and 98 patients showed BSI during the period of agranulocytosis. Multivariate analysis showed that the usage of anti-thymocyte globulin (ATG), long duration of agranulocytosis and low infusion volume of mononuclear cell (MNC) were the independent risk factors affecting BSI after HSCT. Among 121 pathogenic bacteria isolated, 76 Gram-negative (G^-) bacteria (62.8%), 40 Gram-positive (G⁺) bacteria (33.0%), and 5 fungi (4.1%) were detected out. The top three pathogens were Escherichia coli, Staphylococcus epidermidis and Pseudomonas aeruginosa. The drug-resistance rates of Escherichia coli and Klebsiella pneumoniae to carbapenems was 14.3% and 7.7%, respectively, and Pseudomonas aeruginosa was 66.7%. The susceptibility of G⁺ bacteria to vancomycin, linezolid and teicoplanin was 97.5%, 100% and 100%, respectively. The crude mortality rate of the patients with BSI at 100 days after HSCT was significantly higher than that of patients without BSI (P<0.001).

CONCLUSION

The usage of ATG, long duration of agranulocytosis and low infusion volume of MNC are independent risk factors for BSI after HSCT. The pathogens after HSCT are mainly G- bacteria. Pseudomonas aeruginosa is highly resistant to carbapenems. Key words　　;