Risk factors and clinical impact of bacteremia due to carbapenem-nonsusceptible Enterobacteriaceae: A multicenter study in southern Taiwan

Rising threat of metallo-β-lactamase-producing Klebsiella oxytoca complex in Taiwan, 2013-2022

OBJECTIVES

The emergence of metallo-beta-lactamases (MBLs) within the Klebsiella oxytoca complex (CRKO) poses a significant challenge in Taiwan, with so far incomplete characterization of species distribution and carbapenemase variants. This study aimed to elucidate the diversity, variants, and clinical presentations of CRKO isolates collected from 2013 to 2022.

METHODS

We analyzed production of carbapenemases by the modified carbapenem inhibitory method (mCIM) and the NG testTM CARBA-5. Confirmation of five common carbapenemases and multilocus sequence typing were determined by polymerase chain reaction and sequencing. Nanopore whole-genome sequencing was used for the species differentiation and plasmids analysis. We also evaluated the clinical characteristics of the CRKO-infected patients.

RESULTS

Three species were identified: K. michiganensis (n = 102), K. pasteurii (n = 13), and K. oxytoca (n = 3). A majority of isolates (91.5%, n = 108) harbored at least one MBL gene, including blaVIM-1 (n = 56), blaIMP-8 (n = 26), and blaNDM-1 (n = 19), with six isolates carrying dual carbapenemase genes. The blaNDM-1 and blaIMP-8 genes were located on IncFII(Yp) and IncA/C2 plasmids, respectively. Notably, 34.7% of isolates carried kleboxymycin gene clusters (KGC). Using CLSI and EUCAST criteria, 92.4% and 82.4% of isolates, respectively, were susceptible to cefiderocol. Among 92 infected patients, the 30-day mortality rate was 21.7%, associated with female gender, higher Charlson Comorbidity Index, higher Pitt bacteremia scores, presence of bacteremia, and inversely associated with KGC.

CONCLUSION

The high prevalence of CRKO carrying MBLs and the recent surge of the ST27-blaNDM-1 genotype, poses significant treatment challenges and underscores the urgent need for enhanced surveillance in Taiwan.

Clinical Characteristics and Risk Factors for Multidrug-Resistant Enterobacter cloacae Complex Bacteremia in a Chinese Tertiary Hospital: A Decade Review (2013-2022)

Objective

This study aimed to analyze the antimicrobial resistance profiles, clinical characteristics and risk factors of bacteremia caused by Enterobacter cloacae complex (ECC) strains.

Methods

We retrospectively collected clinical data from patients diagnosed with ECC bacteremia between 2013 and 2022 in a tertiary hospital in Jiangsu. Subgroup analyses were performed based on multidrug resistance (MDR), nosocomial acquisition, polymicrobial bacteremia, and mortality.

Results

Among 188 ECC strains, the highest resistance was to ceftriaxone (39.9%), followed by ceftazidime (36.7%) and aztreonam (31.2%), with low resistance to carbapenems (<8.6%) and amikacin (1.6%). MDR ECC accounted for 30.9% (58/188). Previous antibiotic therapy was an independent risk factor for MDR ECC (OR = 3.193, P < 0.020), while appropriate antibiotic therapy significantly reduced the risk (OR = 0.279, P < 0.001). ICU admission was an independent risk factor for polymicrobial bacteremia, both endoscopy and blood transfusion were associated with mortality.

Conclusion

Carbapenems and amikacin are the most effective treatments for ECC bacteremia. Previous antibiotic therapy increases the risk of MDR ECC, while appropriate antibiotic therapy reduces it. ICU admission is an independent risk factor for polymicrobial bacteremia, both endoscopy and blood transfusion are linked to higher mortality. Effective control of MDR ECC bacteremia requires comprehensive strategies, including resistance detection, risk factor identification, and infection prevention.

Real-time artificial intelligence system for bacteremia prediction in adult febrile emergency department patients

BACKGROUND

Artificial intelligence (AI) holds significant potential to be a valuable tool in healthcare. However, its application for predicting bacteremia among adult febrile patients in the emergency department (ED) remains unclear. Therefore, we conducted a study to provide clarity on this issue.

METHODS

Adult febrile ED patients with blood cultures at Chi Mei Medical Center were divided into derivation (January 2017 to June 2019) and validation groups (July 2019 to December 2020). The derivation group was utilized to develop AI models using twenty-one feature variables and five algorithms to predict bacteremia. The performance of these models was compared with qSOFA score. The AI model with the highest area under the receiver operating characteristics curve (AUC) was chosen to implement the AI prediction system and tested on the validation group.

RESULTS

The study included 5,647 febrile patients. In the derivation group, there were 3,369 patients with a mean age of 61.4 years, and 50.7% were female, including 508 (13.8%) with bacteremia. The model with the best AUC was built using the random forest algorithm (0.761), followed by logistic regression (0.755). All five models demonstrated better AUC than the qSOFA score (0.560). The random forest model was adopted to build a real-time AI prediction system integrated into the hospital information system, and the AUC achieved 0.709 in the validation group.

CONCLUSION

The AI model shows promise to predict bacteremia in adult febrile ED patients; however, further external validation in different hospitals and populations is necessary to verify its effectiveness.

Phylogenetic lineages and antimicrobial resistance determinants of clinical Klebsiella oxytoca spanning local to global scales

Klebsiella oxytoca is an opportunistic pathogen causing serious nosocomial infections. Knowledge about the population structure and diversity of healthcare-associated K. oxytoca from a genomic standpoint remains limited. Here, we characterized the phylogenetic relationships and genomic characteristics of 20 K. oxytoca sensu stricto isolates recovered from bloodstream infections at the Dartmouth-Hitchcock Medical Center, New Hampshire, USA from 2017 to 2021. Results revealed a diverse population consisting of 15 sequence types (STs) that together harbored 10 variants of the intrinsic beta-lactamase gene bla OXY-2, conferring resistance to penicillins. Similar sets of antimicrobial resistance (AMR) determinants reside in multiple distinct lineages, with no one lineage dominating the local population. To place the New Hampshire K. oxytoca in a broader context, we compared them to 304 publicly available genomes of clinical isolates from 18 countries. This global clinical K. oxytoca sensu stricto population is represented by over 65 STs that together harbored resistance genes against 14 antimicrobial classes, including eight bla OXY-2 variants. Three dominant STs in the global population (ST2, ST176, ST199) circulate across multiple countries and were also present in the New Hampshire population. The global K. oxytoca population is genetically diverse, but there is evidence for broad dissemination of a few lineages carrying distinct set of AMR determinants. Our findings reveal the clinical diversity of K. oxytoca sensu stricto and its importance in surveillance efforts aimed at monitoring the evolution of this drug-resistant nosocomial pathogen. IMPORTANCE The opportunistic pathogen Klebsiella oxytoca has been increasingly implicated in patient morbidity and mortality worldwide, including several outbreaks in healthcare settings. The emergence and spread of antimicrobial resistant strains exacerbate the disease burden caused by this species. Our study showed that clinical K. oxytoca sensu stricto is phylogenetically diverse, harboring various antimicrobial resistance determinants and bla OXY-2 variants. Understanding the genomic and population structure of K. oxytoca is important for international initiatives and local epidemiological efforts for surveillance and control of drug-resistant K. oxytoca.

Risk Factors and Clinical Impact of Carbapenem-Resistant Enterobacterales Coinfections Among Hospitalized Patients with Clostridioides difficile Infection

Introduction

The risk factors and clinical impact of carbapenem-resistant Enterobacterales (CRE) coinfection among hospitalized patients with Clostridioides difficile infection (CDI) were analyzed in this study.

Materials and Methods

A clinical study was performed at the medical wards of Tainan Hospital, Ministry of Health and Welfare in southern Taiwan. Patients with CDI between January 2013 and April 2020 were included.

Results

Among 238 patients included for analysis, 22 (9.2%) patients developed CRE coinfections within 14 days before or after the onset of CDI. CDI patients with CRE coinfection had longer hospitalization stays (103.0 ± 97.0 days vs 42.5 ± 109.6 days, P = 0.01) than those without CRE coinfection. In the multivariate analysis, age (odds ratio [OR] 1.05, 95% confidence interval [CI] 1.01–1.10, P = 0.02) was independently associated with CRE coinfection. In contrast, underlying old stroke (OR 0.15, 95% CI 0.03–0.70, P = 0.02) was negatively linked to CRE coinfection.

Conclusion

Among patients with CDI, CRE coinfections were associated with prolonged hospitalization for CDI. Age was an independent risk factor for CRE coinfection among patients with CDI.

The Potential of Probiotics to Eradicate Gut Carriage of Pathogenic or Antimicrobial-Resistant Enterobacterales

Probiotic supplements have been used to decrease the gut carriage of antimicrobial-resistant Enterobacterales through changes in the microbiota and metabolomes, nutrition competition, and the secretion of antimicrobial proteins. Many probiotics have shown Enterobacterales-inhibiting effects ex vivo and in vivo. In livestock, probiotics have been widely used to eradicate colon or environmental antimicrobial-resistant Enterobacterales colonization with promising efficacy for many years by oral supplementation, in ovo use, or as environmental disinfectants. In humans, probiotics have been used as oral supplements for infants to decease potential gut pathogenic Enterobacterales, and probiotic mixtures, especially, have exhibited positive results. In contrast to the beneficial effects in infants, for adults, probiotic supplements might decrease potentially pathogenic Enterobacterales, but they fail to completely eradicate them in the gut. However, there are several ways to improve the effects of probiotics, including the discovery of probiotics with gut-protection ability and antimicrobial effects, the modification of delivery methods, and the discovery of engineered probiotics. The search for multifunctional probiotics and synbiotics could render the eradication of “bad” Enterobacterales in the human gut via probiotic administration achievable in the future.