Epidemiology and microbiology of Gram-negative bloodstream infections in a tertiary-care hospital in Beijing, China: a 9-year retrospective study

Epidemiology, Clinical, and Microbiological Characteristics of Multidrug-Resistant Gram-Negative Bacteremia in Qatar

Antimicrobial resistance is a global healthcare threat with significant clinical and economic consequences peaking at secondary and tertiary care hospitals where multidrug-resistant Gram-negative bacteria (MDR GNB) lead to poor outcomes. A prospective study was conducted between January and December 2019 for all invasive bloodstream infections (BSIs) secondary to MDR GNB in Qatar identified during routine microbiological service to examine their clinical, microbiological, and genomic characteristics. Out of 3238 episodes of GNB BSIs, the prevalence of MDR GNB was 13% (429/3238). The predominant MDR pathogens were Escherichia coli (62.7%), Klebsiella pneumoniae (20.4%), Salmonella species (6.6%), and Pseudomonas aeruginosa (5.3%), while out of 245 clinically evaluated patients, the majority were adult males, with the elderly constituting almost one-third of the cohort and with highest observed risk for prolonged hospital stays. The risk factors identified included multiple comorbidities, recent healthcare contact, previous antimicrobial therapy, and admission to critical care. The in-hospital mortality rate was recorded at 25.7%, associated with multiple comorbidities, admission to critical care, and the acquisition of MDR Pseudomonas aeruginosa. Resistant pathogens demonstrated high levels of antimicrobial resistance but noticeable susceptibility to amikacin and carbapenems. Genomic analysis revealed that Escherichia coli ST131 and Salmonella enterica ST1 were the predominant clones not observed with other pathogens.

Distribution and Antibiotic Resistance Analysis of Blood Culture Pathogens in a Tertiary Care Hospital in China in the Past Four Years

Purpose

This study aimed to investigate the antibiotic resistance patterns and clinical distribution of blood culture-positive isolates at Suining Central Hospital between 2018 and 2021. The findings of this study can provide a basis for ensuring rational and effective use of antibiotic therapy in clinical settings.

Methods

This retrospective study analyzed the data of 3660 non-repeating strains that tested positive for clinical blood culture, collected from the microbiology laboratory of Suining Central Hospital between January 2018 and December 2021. The identification of bacterial species and their antibiotic resistance patterns were analyzed.

Results

The study found that 76.7% of the bacterial strains identified were Gram-negative bacteria, while 23.3% were Gram-positive bacteria. Escherichia coli (44.8%), Klebsiella spp. (19.2%), Staphylococcus aureus (9.2%), Enterococcus spp. (5.3%), and Enterobacter spp. were the top five bacterial ratios observed. These bacteria were detected most frequently in the Digestion Center, intensive care unit (ICU), Neurology Center, Urology Department, and Hematology Department. Among the Staphylococcus spp., methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MRCNS) were detected at rates of 39.3% and 71.8%, respectively. However, no vancomycin- or linezolid-resistant staphylococci were identified. Enterococcus faecalis showed higher susceptibility to most antibiotic than Enterococcus faecium, except for tetracycline. The resistance rates of E. coli and Klebsiella spp. to meropenem and imipenem were low, but the resistance rates for other antibiotic were above 40%.

Conclusion

The results of this study show a rising incidence of bacterial antibiotic resistance in positive blood culture specimens at Suining Central Hospital. Clinicians should carefully consider the importance of blood culture antibiotic susceptibility testing to ensure effective treatment. The Department of Microbiology at Suining Central Hospital should regularly analyze the distribution of pathogenic bacteria and antibiotic resistance in blood cultures to ensure the most effective treatment possible.

Distribution and Antibiotic Resistance Characteristics of Bacteria Isolated from Blood Culture in a Teaching Hospital in Vietnam During 2014-2021

Purpose

Studies on the epidemiology of bloodstream infection (BSI) and antimicrobial resistance (AMR) are limited in Vietnam. Thus, the present study aimed to elucidate the epidemiology of BSI and AMR of BSI-causing bacteria in Vietnam.

Methods

Data regarding blood cultures from 2014 to 2021 were collected and analyzed using the chi-square test, Cochran-Armitage test, and binomial logistic regression model.

Results

Overall, 2405 (14.15%) blood cultures were positive during the study period. In total, 55.76% of BSIs occurred in patients aged ≥60 years. The male-to-female ratio of patients with BSI was 1.87:1. Escherichia coli (26.11%), Staphylococcus aureus (15.79%), Klebsiella pneumoniae (10.44%), Acinetobacter baumannii (4.70%), and Pseudomonas aeruginosa (3.45%) were the leading bacterial species causing BSI. The AMR rate of these bacteria isolated in the intensive care unit (ICU) was significantly higher compared with that of those in other wards. E. coli was the least resistant to carbapenems (2.39%-4.14%), amikacin (3.85%), and colistin (11.54%) and most resistant to penicillins (>80.0%). S. aureus was the least resistant to glycopeptides (0%-3.38%), quinupristin-dalfopristin (0.59%), and linezolid (1.02%) and most resistant to clindamycin (71.57%). K. pneumoniae was the least resistant to ertapenem (8.86%), amikacin (9.39%), and colistin (15.38%) and most resistant to aztreonam (83.33%). A. baumannii was the least resistant to amikacin (16.67%) and colistin (16.67%) and highly resistant to other antibiotics (≥50.0%). P. aeruginosa was the least resistant to colistin (16.33%) and piperacillin (28.17%) and highly resistant to other antibiotics (≥50.0%). Notably, the multidrug resistance rate of E. coli (76.41%) was the highest among common pathogens, followed by A. baumannii (71.57%), P. aeruginosa (64.56%), S. aureus (56.99%), and K. pneumoniae (43.72%).

Conclusion

The AMR rate of BSI-causing bacteria, particularly strains isolated from ICU, was alarmingly high. There is a need for new antibiotics, therapeutic strategies, as well as prevention and control to combat BSI and AMR.

The association of ESBL Escherichia coli with mortality in patients with Escherichia coli bacteremia at the emergency department

Background: Escherichia coli is a common bloodstream infection pathogen in the emergency department (ED). Patients with extended-spectrum beta-lactamase (ESBL) E. coli have a higher risk of morbidity. However, there is still debate surrounding ESBL E. coli-associated mortality in community, intensive care unit, and tertiary care settings. In addition, there have been few studies regarding mortality in ESBL E. coli in ED settings, and results have been contradictory. Methods: This was a retrospective cohort study conducted at the Department of Emergency Medicine, Faculty of Medicine, Khon Kaen University in Thailand aimed at evaluating the possible association between ESBL E. coli bacteremia and mortality in the ED. The inclusion criteria were age 18 years or over, clinical presentation suspicious of infection, and positive blood culture for E. coli. Predictors for mortality were analyzed by logistic regression analysis. Results: During the study period, 273 patients presented at the ED with hemoculture positive for E. coli. Of those, 27 (9.89%) died. Five factors remained in the final model, of which plasma glucose levels, serum lactate levels, and ESBL E. coliwere significantly associated with 28-day mortality in the ED with adjusted odds ratios of 0.970, 1.258, and 12.885, respectively. Plasma glucose of less than 113 mg/dL yielded a sensitivity of 80.95% and specificity of 64.29%, while serum lactate over 2.4 mmol/L had a sensitivity of 81.48% and specificity of 45.50%. Conclusion: ESBL E. coli, plasma glucose, and serum lactate levels were associated with 28-day mortality in patients with E. coli bacteremia presenting at the ED.

Trends of Bloodstream Infections in a University Hospital During 12 Years

This study aims to investigate trends in bloodstream infections and their antimicrobial susceptibility profiles over 12 years in our hospital. This retrospective study was carried out in the Bursa Uludag University Hospital, Turkey, during 2008–2019. Blood cultures from patients were performed using BACTEC System. Isolates were identified with Phoenix System until 2018 and “matrix-assisted laser desorption ionization time-of-flight mass spectrometry” (MALDI-TOF MS) in 2019. Antibiotic susceptibility testing was performed with Phoenix System. Patient data came from the BD EpiCenter™ data management system. Escherichia coli was found to be the most common Gram-negative (11.6%), and coagulase-negative staphylococci were the most common Gram-positive (10.1%) monomicrobial growth. Overall, there was a significant increase in rates of extended-spectrum β-lactamase positive E. coli (p = 0.014) and Klebsiella pneumonia (p < 0.001), carbapenem-resistant E. coli (p < 0.001), and K. pneumoniae (p < 0.001) and colistin-resistant K. pneumoniae (p < 0.001) and Acinetobacter baumannii (p < 0.001) over 12 years. Carbapenem and colistin resistance has increased dramatically in recent years. We believe that regular monitoring of the distribution of pathogens and antibiotic susceptibility profiles, especially in intensive care units, can contribute to evidence for the increase in resistant microorganisms and help prevent their spread with antimicrobial stewardship and infection control policies.

Risk Factors for a Hospital-Acquired Carbapenem-Resistant Klebsiella pneumoniae Bloodstream Infection: A Five-Year Retrospective Study

Purpose

This study aimed to describe trends in Klebsiella pneumoniae (KP) resistance in bloodstream infections (BSI) and to identify risk factors for a hospital-acquired carbapenem-resistant Klebsiella pneumoniae (CRKP) BSI and 28-day mortality from a hospital-acquired KP BSI.

Patients and Methods

We recorded the results of antimicrobial susceptibility testing of 396 KP-positive blood cultures from January 2016 to December 2020. A total of 277 patients with a KP BSI were included in this study, of which 171 had a hospital-acquired infection and 84 had a hospital-acquired CRKP BSI. Multivariate logistic regression analysis was used to identify risk factors for a hospital-acquired CRKP BSI and 28-day mortality from a hospital-acquired KP BSI.

Results

The proportion of hospital-acquired infections among KP BSI patients increased from 53.1% in 2016 to 72.8% in 2020. The detection rate of CRKP among KP BSI patients increased from 18.8% in 2016 to 37.7% in 2020. Multivariate logistic regression showed that β-lactam/β-lactamase inhibitor combinations (BLBLIs) exposure (P  = 0.022, OR 2.863), carbapenems exposure (P  = 0.007, OR 3.831) and solid organ transplantation (P   <0.001, OR 19.454) were independent risk factors for a hospital-acquired CRKP BSI. Risk factors for a 28-day mortality from hospital-acquired KP BSI were CRKP BSI (P  =0.009, OR 5.562), septic shock (P  =0.002, OR 4.862), mechanical ventilation>96 hours (P =0.020, OR 8.765), and platelet counts <100×10⁹/L (P  =0.003, OR 4.464).

Conclusion

The incidence of hospital-acquired KP BSI continues to rise and the proportion of CRKP BSI is also increasing. We believe that the use of the BLBLIs needs to be carefully evaluated in hospital-acquired infection. Hospital-acquired KP BSI Patients with CRKP BSI, septic shock, mechanical ventilation and deficiency of platelets are more likely to have a poor prognosis.