OBJECTIVE: To analyze the clinical characteristics, microbiological analysis, and drug resistance patterns of intensive care unit (ICU) bloodstream infection. METHODS: A prospective cohort study method was employed to collect clinical data from patients suspected of bloodstream infection (BSI) during their stay in ICUs across 67 hospitals in 16 provinces and cities nationwide, from July 1, 2021, to December 31, 2022. Electronic data collection technology was used to gather general information on ICU patients, including gender, age, length of hospital stay, as well as diagnostic results, laboratory tests, imaging studies, microbiological results (including smear, culture results, and pathogen high-throughput testing), and prognosis. Patients were divided into a BSI group and a non-BSI group based on the presence or absence of BSI; further, patients with BSI were categorized into a drug-resistant group and a non-drug-resistant group based on the presence or absence of drug resistance. Differences in the aforementioned indicators between groups were analyzed and compared; variables with P < 0.10 in the univariate analysis were included in a multivariate Logistic regression analysis to identify risk factors for mortality and drug resistance in ICU patients with BSI. RESULTS: A total of 2 962 ICU patients suspected of BSI participated in the study, including 790 in the BSI group and 2 172 in the non-BSI group. Patients in the BSI group were mainly from East China and Southwest China, with significantly higher age and mortality rates than those in the non-BSI group. Among ICU patients with BSI, Staphylococcus had the highest detection rate (8.10%), followed by Klebsiella pneumoniae (7.47%); there were 169 cases in the drug-resistant group and 621 cases in the non-drug-resistant group; 666 cases survived, and 124 cases died (mortality was 15.70%). There were statistically significant differences between the death group and the survival group in terms of age, regional distribution, and bloodstream infections caused by Gram negative (G^-) bacilli, Enterococcus faecium, Aspergillus, and Klebsiella pneumoniae; multivariate Logistic regression analysis showed that age [odds ratio (OR) = 1.01, 95% confidence interval (95%CI) was 1.00-1.03], regional distribution (OR = 4.07, 95%CI was 1.02-1.34), Enterococcus faecium infection (OR = 3.64, 95%CI was 1.16-11.45), and Klebsiella pneumoniae infection (OR = 2.64,95%CI was 1.45-4.80) were independent risk factors for death in ICU patients with BSI (all P < 0.05). There were statistically significant differences between the drug-resistant group and the non-drug-resistant group in terms of age and bloodstream infections caused by Gram positive (G⁺) cocci and G^- bacilli; multivariate Logistic regression analysis showed that age (OR = 1.01,95%CI was 1.00-1.03), G^- bacilli infection (OR = 2.18, 95%CI was 1.33-3.59), Escherichia coli infection (OR = 0.28,95%CI was 0.09-0.84), and Enterococcus faecium infection (OR = 3.35, 95%CI was 1.06-10.58) were independent risk factors for drug resistance in ICU patients with BSI (all P < 0.05). CONCLUSIONS Bloodstream infections may increase the mortality of ICU patients. Older age, regional distribution, Enterococcus faecium infection and Klebsiella pneumoniae infection can increase the mortality rate of ICU patients with BSI; bloodstream infections caused by G^- bacilli are prone to drug resistance, but have no significant impact on the mortality of ICU patients with BSI.
Adult ; Humans ; Bacteremia/microbiology* ; China/epidemiology* ; Cohort Studies ; Cross Infection/microbiology* ; Drug Resistance, Bacterial ; Intensive Care Units/statistics & numerical data* ; Prospective Studies ; Risk Factors ; Sepsis/microbiology*

OBJECTIVES: Bloodstream infections in emergency patients have a high incidence, severe disease progression, and rapid deterioration. Early administration of appropriate antimicrobial agents is crucial for improving patient outcomes. This study aims to investigate the incidence, pathogen distribution, and antimicrobial resistance patterns of bloodstream infections in emergency patients, providing a reference for rational antibiotic use in clinical practice. METHODS: Medical records of patients diagnosed with bloodstream infections in the emergency department of a hospital in Hunan Province between January 2018 and October 2022 were retrospectively collected. Clinical characteristics of bloodstream infection patients were analyzed, and the distribution trends and antimicrobial susceptibility of clinical isolates were examined. RESULTS: During the study period, 2 215 blood culture samples were submitted from the emergency department, with a positivity rate of 13.27%. After excluding eight cases with missing data or suspected contamination, 286 patients with bloodstream infections were included, with community-acquired infections accounting for the majority (85.66%). The most common primary infection site was the urinary tract (24.48%), followed by respiratory tract infections (20.28%) and biliary and intra-abdominal infections (17.13%). The 30-day mortality rate of bloodstream infections was 16.08%. A total of 286 pathogens were isolated, including 181 (63.29%) Gram-negative bacteria, primarily Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa; 101 (35.31%) Gram-positive bacteria, mainly Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus pneumoniae; and only 4 (1.40%) fungal isolates. Antimicrobial susceptibility testing showed that the key Enterobacteriaceae strains exhibited resistance rates of 2.4% to carbapenems, 16.3% to piperacillin sodium and tazobactam sodium, and 15.3% to ceftazidime, with no detected resistance to tigecycline or polymyxins. The main non-fermentative bacteria showed resistance rates of 29.6% to piperacillin sodium and tazobactam sodium, 13.3% to cefoperazone sodium and sulbactam sodium, and 27.1% to quinolones. Among Gram-negative bacteria, multidrug-resistant strains accounted for 40.9% (74/181), with carbapenem-resistant Escherichia coli and Klebsiella pneumoniae detected in 5.4% (5/92) and 13.6% (6/44) of cases, respectively. No carbapenem-resistant Pseudomonas aeruginosa was identified. Among Gram-positive bacteria, resistance rates to penicillin G, rifampicin, and cefoxitin were 74.7%, 4.2%, and 50%, respectively, with only 3 cases of resistant to glycopeptide antibiotics. CONCLUSIONS Bloodstream infections in emergency patients are predominantly community-acquired, with Gram-negative bacteria being the most common pathogens. The isolated pathogens exhibited relatively low resistance rates to commonly used clinical antibiotics.
Retrospective Studies ; Emergency Service, Hospital/statistics & numerical data* ; Drug Resistance, Bacterial ; Anti-Bacterial Agents/therapeutic use* ; Incidence ; Microbial Sensitivity Tests/statistics & numerical data* ; Bacteremia/microbiology* ; Community-Acquired Infections/microbiology* ; Gram-Negative Bacteria/isolation & purification* ; Blood Culture/statistics & numerical data* ; Humans ; Male ; Female ; Adolescent ; Young Adult ; Adult ; Middle Aged ; Aged ; Aged, 80 and over ; China/epidemiology*

Humans ; Bacteremia ; Cross Infection ; Methicillin-Resistant Staphylococcus aureus ; Retrospective Studies ; Sepsis ; Staphylococcal Infections/epidemiology* ; Staphylococcus aureus ; Tertiary Care Centers ; China

Humans ; Escherichia coli ; Klebsiella pneumoniae ; Retrospective Studies ; Hospitals, General ; Singapore/epidemiology* ; Escherichia coli Infections/epidemiology* ; Sepsis/drug therapy* ; beta-Lactamases ; Anti-Bacterial Agents/therapeutic use* ; Bacteremia/drug therapy* ; Microbial Sensitivity Tests

Objective: To study the incidence of bloodstream infections, pathogen distribution, and antibiotic resistance profile in patients with hematological malignancies. Methods: From January 2018 to December 2021, we retrospectively analyzed the clinical characteristics, pathogen distribution, and antibiotic resistance profiles of patients with malignant hematological diseases and bloodstream infections in the Department of Hematology, Nanfang Hospital, Southern Medical University. Results: A total of 582 incidences of bloodstream infections occurred in 22,717 inpatients. From 2018 to 2021, the incidence rates of bloodstream infections were 2.79%, 2.99%, 2.79%, and 2.02%, respectively. Five hundred ninety-nine types of bacteria were recovered from blood cultures, with 487 (81.3%) gram-negative bacteria, such as Klebsiella pneumonia, Escherichia coli, and Pseudomonas aeruginosa. Eighty-one (13.5%) were gram-positive bacteria, primarily Staphylococcus aureus, Staphylococcus epidermidis, and Enterococcus faecium, whereas the remaining 31 (5.2%) were fungi. Enterobacteriaceae resistance to carbapenems, piperacillin/tazobactam, cefoperazone sodium/sulbactam, and tigecycline were 11.0%, 15.3%, 15.4%, and 3.3%, with a descending trend year on year. Non-fermenters tolerated piperacillin/tazobactam, cefoperazone sodium/sulbactam, and quinolones at 29.6%, 13.3%, and 21.7%, respectively. However, only two gram-positive bacteria isolates were shown to be resistant to glycopeptide antibiotics. Conclusions: Bloodstream pathogens in hematological malignancies were broadly dispersed, most of which were gram-negative bacteria. Antibiotic resistance rates vary greatly between species. Our research serves as a valuable resource for the selection of empirical antibiotics.
Humans ; Bacteremia/epidemiology* ; Cefoperazone ; Sulbactam ; Retrospective Studies ; Drug Resistance, Bacterial ; Microbial Sensitivity Tests ; Hematologic Neoplasms ; Sepsis ; Anti-Bacterial Agents/pharmacology* ; Gram-Negative Bacteria ; Gram-Positive Bacteria ; Piperacillin, Tazobactam Drug Combination ; Escherichia coli

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　　;
Bacteremia/epidemiology* ; Bacteria ; Hematopoietic Stem Cell Transplantation ; Humans ; Retrospective Studies ; Sepsis

PURPOSE: We aimed to investigate the epidemiological characteristics of Staphylococcus aureus bacteremia in Korean children. METHODS: We retrospectively collected and analyzed data from the medical records of the patients with S. aureus bacteremia ≤18 years of age in Gil Medical Center from 2002 to 2016. RESULTS: A total of 212 SAB cases were detected. The annual incidence of SAB from 2002 to 2016 ranged from 0.77 to 1.95 per 1,000 patients hospitalized. The neonate group (<28 days of age) and the pediatric group (28–18 years of age) were 51.4% (n=109) and 48.6% (n=103), respectively. According to the origin of infection, there were 93 cases (43.9%) of community-associated (CA)-SAB and 119 cases (56.1%) of healthcare-associated (HA)-SAB. The rates of HA-SAB among the neonate group and among the pediatric group were 64.2% and 47.6%, respectively (P=0.015). There was no difference in complications between CA-SAB and HA-SAB, but mortality was higher in HA-SAB. The proportion of methicillin-resistance S. aureus (MRSA) was the highest in neonates (88.1%), decreased with age, and was 36.4%–37.5% among children aged ≥5 years. The MRSA proportion was 72.2%, showing no consistent trend over the period. CONCLUSIONS: The annual incidence of SAB and the proportion of MRSA in SAB remained constant in the recent 15 years in children. Judicious decision of antimicrobial agents for treatment considering the patient's age and the origin of infection is necessary.
Anti-Infective Agents ; Bacteremia ; Child ; Epidemiology ; Humans ; Incidence ; Infant ; Infant, Newborn ; Medical Records ; Methicillin-Resistant Staphylococcus aureus ; Mortality ; Retrospective Studies ; Staphylococcus aureus ; Staphylococcus

Escherichia coli can harbor genomic pks islands that code for a polyketide-peptide genotoxin known as colibactin. E. coli strains carrying pks islands trigger genetic instability. pks islands have been significantly associated with bacteremia. We investigated the molecular epidemiology of bacteremic E. coli isolates and the prevalence of bacteremia-causing E. coli carrying pks islands. A total of 146 E. coli isolates were collected at a tertiary-care hospital from January 2015 to December 2016. The phylogenetic groups were determined by multiplex PCR. All isolates were screened by PCR for sequence type 131 (ST131)-associated single-nucleotide polymorphisms (SNPs) in mdh and gyrB. For detection of pks islands, we performed PCR for the clbB and clbN genes as colibactin system markers. Phylogenetic group B2 was the most common, accounting for 54.1% (N=79) of the isolates, followed by group D with 29.5% (N=43), group A with 11.6% (N=17), and group B1 with 4.8%. Of the group B2 isolates, 40.5% were ST131 strains and 32.9% carried pks islands. Only three ST131 isolates in group B2 carried the clbB and clbN genes, while the other 23 ST131 isolates did not. The pks gene might not be associated with ST131 strains.
Bacteremia* ; Escherichia coli* ; Escherichia* ; Humans ; Islands* ; Molecular Epidemiology ; Multiplex Polymerase Chain Reaction ; Polymerase Chain Reaction ; Prevalence*

BACKGROUND: Invasive bacterial infections in apparently immunocompetent children were retrospectively analyzed to figure causative bacterial organisms in Korea. METHODS: A total of 947 cases from 25 university hospitals were identified from 2006 to 2010 as a continuance of a previous 10-year period study from 1996 to 2005. RESULTS: Escherichia coli (41.3%), Streptococcus agalactiae (27.7%), and Staphylococcus aureus (27.1%) were the most common pathogens in infants < 3 months of age. S. agalactiae was the most prevalent cause of meningitis and pneumonia and E. coli was the major cause of bacteremia without localizing signs in this group. In children 3 to 59 months of age, Streptococcus pneumoniae (54.2%), S. aureus (20.5%), and Salmonella spp. (14.4%) were the most common pathogens. S. pneumoniae was the leading cause of pneumonia (86.0%), meningitis (65.0%), and bacteremia without localizing signs (49.0%) in this group. In children ≥ 5 years of age, S. aureus (62.8%) was the predominant pathogen, followed by Salmonella species (12.4%) and S. pneumoniae (11.5%). Salmonella species (43.0%) was the most common cause of bacteremia without localizing signs in this group. The relative proportion of S. aureus increased significantly over the 15-year period (1996–2010) in children ≥ 3 months of age (P < 0.001), while that of Haemophilus influenzae decreased significantly in both < 3 months of age group (P = 0.036) and ≥ 3 months of age groups (P < 0.001). CONCLUSION: S. agalactiae, E. coli, S. pneumoniae, and S. aureus are common etiologic agents of invasive bacterial infections in Korean children.
Bacteremia ; Bacterial Infections ; Child ; Epidemiology ; Escherichia coli ; Haemophilus influenzae ; Hospitals, University ; Humans ; Infant ; Korea ; Meningitis ; Pneumonia ; Retrospective Studies ; Salmonella ; Staphylococcus aureus ; Streptococcus agalactiae ; Streptococcus pneumoniae

OBJECTIVE: To investigate the phylogenetics and prevalence of bloodstream infections with ST131, the antimicrobial resistance profiles of the pathogens, and the clinical features. METHODS: Non-duplicate isolates were collected from 144 patients with bloodstream infections in our hospital between January and December, 2016.The phylogenetic groups of the isolates were analyzed using multiplex PCR, and O serotyping of ST131 strains was performed by allele-specific PCR.The clinical characteristics of the 144 patients were analyzed to define the differences in the clinical features between patients with ST131 infection and those with non-ST131 infection.Antibiotic susceptibility of the isolates was determined using the Vitek 2 compact system. RESULTS: The phylogenetic group analysis showed a domination by group B2 (41.0%[59/144]), followed by group F, group B1 and group E, which accounted for 16.7%(24/144), 13.9%(20/144), and 13.2% (19/144), respectively.Nine strains (6.3%) of were identified to be ST131 strains, among which 8 were O25b-B2-ST131 strains and 1 was O16-B2-ST131 strain.Of the 9 cases of ST131 infection, 7(77.8%) were found to occur in a nosocomial setting.The demographic characteristics and clinical features of the ST131-infected patients were similar to those of non-ST131-infected patients.ST131 strains were sensitive to piperacillin/tazobactam, imipenem, ertapenem, and amikacin, but showed high resistance rates to cefazolin, ceftriaxone, ciprofloxacin, levofloxacin, gentamicin, and trimethoprim/ sulfamethoxazole (all over 50%).The positivity rate of ESBLs in the ST131 strains was 77.8%, and the multidrug resistance rate reached 88.9%, which was higher than that of non-ST131 isolates, but the difference was not statistically significant. CONCLUSIONS The most common phylogenetic groups of isolates from patients with bloodstream infections are group B2 and F, and the positivity rate of ST131 is low.We for the first time detected O16-ST131 in patients with blood-borne infections in China.The clinical features of ST131-infected patients are similar to those of non-ST131-infected patients.The positivity rate of ESBLs and the multidrug resistance rate are high in ST131 strains, which may raise concerns in the future.
Anti-Bacterial Agents ; therapeutic use ; Bacteremia ; drug therapy ; epidemiology ; microbiology ; China ; Drug Resistance, Bacterial ; Escherichia coli ; classification ; drug effects ; genetics ; Escherichia coli Infections ; drug therapy ; epidemiology ; microbiology ; Genotype ; Humans ; Microbial Sensitivity Tests ; Molecular Epidemiology ; Phylogeny ; Species Specificity