Enterobacter Infections Research Articles

Meropenem-vaborbactam as intrathecal-sparing therapy for the treatment of carbapenem-resistant K. pneumoniae shunt-related ventriculitis: two case reports and review of the literature.

Recently, an increase in cases of multidrug-resistant Gram-negative bacteria post-neurosurgical ventriculitis and meningitis is reported. Treating these infections has become challenging due to the limited availability of antibiotics and the need to select those with optimal pharmacodynamic and pharmacokinetic profiles. There is limited evidence regarding the use of meropenem-vaborbactam in treating carbapenem-resistant Enterobacterales infections of the central nervous system. We report two new cases of shunt-related ventriculitis due to carbapenem-resistant K.pneumoniae with a favorable microbiological evolution after IV only combination therapy with meropenem-vaborbactam.

Evaluating the clinical utility of cervical cultures in postpartum endometritis management.

To evaluate the utility of cervical cultures in the diagnosis and management of postpartum endometritis. A retrospective study was conducted on 1069 cervical cultures collected from postpartum women with suspected endometritis between 2011 and 2021. Patient demographics, obstetric history, clinical parameters, and culture results were analyzed. Microorganisms were categorized into five groups based on species and virulence. Statistical analysis was performed to identify associations between risk factors, pathogens, and disease severity. The positivity rate for distinct microorganisms in cervical cultures was 33.1%. Escherichia coli (10.8%) and Group B Streptococcus (7.5%) were the most common isolates. Prolonged labor duration and prolonged rupture of membranes were associated with Enterobacterales infections. Elevated white blood cell count was linked to Enterobacterales and beta-hemolytic Streptococci, while the former were also associated with higher rate of postpartum clinic visit. No significant differences in disease severity were found between other microorganism groups. The study suggests that while cervical cultures can identify potential pathogens in postpartum endometritis, their clinical utility is questionable due to the polymicrobial nature of the disease and the isolation of commensal microorganisms. The lack of significant differences in disease severity across various microorganism groups raises questions regarding the contribution of distinct bacterial identification in endometritis management.

Association of Race or Ethnicity With Extended-Spectrum Beta-Lactamase Production in Escherichia Coli: A Case Control Study.

There are limited and conflicting data regarding the impact of race or ethnicity on the rate of gram-negative antimicrobial resistance. This study was performed to determine whether there is a difference in extended-spectrum beta-lactamase (ESBL) Escherichia coli infection or colonization in minoritized patients when compared to White patients from a diverse US Midwestern city. A case control study was performed, with controls with non-ESBL E. coli matched 1:1 to patients with ESBL-producing E coli based on age, sex, and ZIP code. A variety of other evidence-based factors for ESBL Enterobacterales infection and colonization were collected via chart review. Multivariate conditional logistic regression assessed the odds of minoritized patients as compared to White patients, while controlling for other common risk factors for ESBL Enterobacterales. A total of 364 matched pairs were included in the analysis. Females were the majority of the sample (91%), with median age of 65 years. The majority of the sample identified as White (73%), followed by Hispanic (14%) and Black (10%). Urine cultures made up the majority of the cultures in the sample (97%), and this was similar between ESBL and non-ESBL groups. While controlling for these risk factors for ESBL E coli, minoritized patients had a statistically significant greater odds of ESBL-producing E coli (odds ratio, 2.53; 95% confidence interval, 1.68-3.82). In our sample, which is demographically similar to the United States, minoritized patients had higher odds of ESBL-producing E coli. Further research on the drivers for this disparity is needed.

Engineered phage therapy for the effective treatment of recurrent Carbapenem-resistant Enterobacteriaceae infections: A hypothesis

The increasing rate of Carbapenem-resistant Enterobacteriaceaer (CRE) infections poses a significant threat to global public health. Patients infected with CRE often experience frequent recurrences after antibiotic treatment, making it difficult to cure. The design of better antimicrobials that can not only kill CRE but also disrupt biofilms and eliminate persister cells will play a crucial role in improving antibacterial efficacy and preventing recurrent infections. In this hypothesis, we employ an innovative “water pipe” theory to elucidate the potential underlying causes of CRE infection recurrence. We propose a potential therapeutic approach utilizing engineered phages to combat CRE infections, demonstrating the mechanism of action of phages carrying lytic enzymes or antimicrobial peptides against biofilms and persister cells. Furthermore, we evaluate its efficacy and feasibility, which may effectively address the recurrence of CRE infections and reduce antibiotic usage.

Phenotypic and molecular characterization of multidrug-resistant Enterobacterales isolated from clinical samples in Palestine: a focus on extended-spectrum β-lactamase- and carbapenemase-producing isolates

BackgroundInfections resulting from multidrug-resistant Enterobacterales (MDR-E) pose a growing global threat, presenting challenges in treatment and contributing significantly to morbidity and mortality rates. The main objective of this study was to characterize phenotypically and genetically extended-spectrum β-lactamase- and carbapenemase- producing Enterobacterales (ESBLE and CPE respectively) isolated from clinical samples in the West Bank, Palestine.MethodsA cross sectional study was conducted in October 2023 on clinical bacterial isolates collected from five governmental hospitals in the West Bank, Palestine. The isolates obtained from the microbiology laboratories of the participating hospitals, underwent identification and antibiotic susceptibility testing (AST) using the VITEK® 2 Compact system. ESBL production was determined by the Vitek2 Compact system. A modified carbapenem inactivation method (mCIM) was employed to identify carbapenemase-producing Enterobacterales (CPE). Resistance genes were detected by real-time PCR.ResultsOut of the total 1380 collected isolates, we randomly selected 600 isolates for analysis. Our analysis indicated that 287 (47.83%) were extended-spectrum beta-lactamase producers (ESBLE), and 102 (17%) as carbapenem-resistant Enterobacterales (CRE) isolates. A total of 424 isolates (70.67%) were identified as multidrug-resistant Enterobacterales (MDRE). The most prevalent ESBL species were K. pneumoniae (n = 124; 43.2%), E. coli (n = 119; 41.5%) and E. cloacae (n = 31; 10.8%). Among the CRE isolates, 85 (83.33%) were carbapenemase-producing Enterobacterales (CPE). The most frequent CRE species were K. pneumoniae (n = 63; 61.7%), E. coli (n = 25; 24.5%) and E. cloacae (n = 13; 12.8%). Additionally, 47 (7.83%) isolates exhibited resistance to colistin (CT), with 38 (37.62%) being CT-resistant CRE and 9 (3.14%) being CT-resistant ESBLE while sensitive to carbapenems. We noticed that 11 isolates (6 Klebsiella pneumoniae and 5 Enterobacter cloacae complex) demonstrated sensitivity to carbapenems by phenotype but carried silent CPE genes (1 blaOXA48, and 6 blaNDM, 4 blaOXA48, blaNDM). ESBL-producing Enterobacterales strains exhibited varied resistance patterns across different antibiotic classes. E. coli isolates showed notable 48% resistance to trimethoprim/sulfamethoxazole. K. pneumoniae isolates displayed a significant resistance to trimethoprim/sulfamethoxazole, nitrofurantoin, and fosfomycin (54%, 90%, and 70% respectively). E. cloacae isolates showed complete resistance to nitrofurantoin and fosfomycin. P. mirabilis isolates exhibited high resistance against fluoroquinolones (83%), and complete resistance to trimethoprim/sulfamethoxazole, nitrofurantoin and fosfomycin.ConclusionThis study showed the high burden of the ESBLE and CRE among the samples collected from the participating hospitals. The most common species were K. pneumoniae and E. coli. There was a high prevalence of blaCTXm. Adopting both conventional and molecular techniques is essential for better surveillance of the emergence and spread of antimicrobial-resistant Enterobacterales infections in Palestine.

Efficacy and safety of ertapenem dosing in patients with ESBL producing Enterobacterales infections utilizing renal replacement therapies.

The clinical efficacy and safety of ertapenem use in patients undergoing renal replacement therapies (RRT) are not well-documented. Therefore, we aimed to investigate the safety and efficacy of ertapenem in patients with sepsis secondary to Enterobacterales who are undergoing RRT. A retrospective cohort study was conducted on patients who met the inclusion criteria at our hospital between May 2015 and December 2021. The primary endpoint was 30-day mortality. Secondary endpoints included clinical cure, microbiologic cure, recurrence rate, and incidence of seizures. During the study period, 158 patients met the inclusion criteria. Of these, 86 were male (54.4%), the mean age was 66.4 ± 13.8 years, and the mean weight was 77 ± 22.4 kg. The most common diagnosis was bacteremia in 48 (30.4%) subjects, followed by urinary tract infection in 39 (24.7%) subjects, and pneumonia in 35 (22.2%) patients. The most isolated pathogens were Escherichia coli, followed by Klebsiella species. The median ertapenem dose was 0.5 g intravenously (IV) daily in those who received intermittent hemodialysis (IHD) and 1 g IV daily for those who received continuous veno-venous hemofiltration (CVVH). The 30-day mortality rate was 24%, the clinical cure rate was 89.2%, the microbiologic cure rate was 82%, the 30-day recurrence rate was 41.1%, and the incidence of seizures was 2.5%. Multivariate logistic regression analysis indicated that age (OR 1.04 [95% CI: 1.003-1.075]), being critically ill at therapy initiation (OR 2.9 [95% CI: 1.1-7.5]), and Enterobacterales other than Klebsiella species and Escherichia coli (OR 3.8 [95% CI: 1.1-12.5]) were significant independent risk factors associated with mortality in this population. Ertapenem dose was not associated with mortality. Our findings suggest that the commonly used doses of ertapenem in patients undergoing IHD and CVVH are clinically effective but may pose a higher risk of seizures. A comprehensive pharmacokinetic study is needed to determine the most effective and safe dose for this population.

Risk factors for bloodstream infections due to carbapenem-resistant Enterobacterales: a nested case-control-control study.

Carbapenem-resistant Enterobacterales (CRE) bloodstream infections (BSIs) are a major threat to patients. To date, data on risk factors have been limited, with low internal and external validity. In this multicentre study, risk factors for CRE BSI were determined by comparison with two control groups: patients with carbapenem-susceptible Enterobacterales (CSE) BSI, and patients without Enterobacterales infection (uninfected patients). A multicentre, case-control-control study was nested in a European prospective cohort study on CRE (EURECA). CRE BSI:CSE BSI matching was 1:1, CRE BSI:Uninfected patients matching was 1:3, based on hospital, ward and length of stay. Conditional logistic regression was applied. From March 2016 to November 2018, 73 CRE BSIs, 73 CSE BSIs and 219 uninfected patients were included from 18 European hospitals. For CRE versus CSE BSI, previous CRE colonization/infection [incidence rate ratio (IRR) 7.32; 95% CI 1.65-32.38) increased the risk. For CRE versus uninfected controls, independent risk factors included: older age (IRR 1.03; 95% CI 1.01-1.06), patient referral (long-term care facility: IRR 7.19; 95% CI 1.51-34.24; acute care hospital: IRR 5.26; 95% CI 1.61-17.11), previous colonization/infection with other MDR organisms (MDROs) (IRR 9.71; 95% CI 2.33-40.56), haemodialysis (IRR 8.59; 95% CI 1.82-40.53), invasive procedures (IRR 5.66; 95% CI 2.11-15.16), and β-lactam/β-lactamase inhibitor combinations (IRR 3.92; 95% CI 1.68-9.13) or third/fourth generation cephalosporin (IRR 2.75; 95% CI 1.06-7.11) exposure within 3 months before enrolment. Evidence of previous CRE colonization/infection was a major risk factor for carbapenem resistance among Enterobacterales BSI. Compared with uninfected patients, evidence of previous MDRO colonization/infection and healthcare exposure were important risk factors for CRE BSI. Targeted screening, infection prevention and antimicrobial stewardship should focus on these high-risk patients.

Hospital mortality and length of stay associated with Enterobacterales positive blood cultures: a multicenter analysis.

Delayed time to antimicrobial susceptibility results can impact patients' outcomes. Our study evaluated the impact of susceptibility turnaround time (TAT) and inadequate empiric antibacterial therapy (IET) in patients with bloodstream infections (BSI) caused by Enterobacterales (ENT) species on in-hospital mortality and length of stay (LOS). This retrospective, multicenter investigation which included 29,570 blood ENT-positive admissions across 161 US healthcare facilities evaluated the association between antimicrobial susceptibility testing (AST) TAT, carbapenem susceptibility, and empiric therapy on post-BSI in-hospital mortality and LOS following an ENT BSI event in adult patients. After adjusting for outcomes covariates, post-BSI in-hospital mortality was significantly higher for patients in the IET vs adequate empiric therapy (AET) group [odds ratio (OR): 1.61 (95% CI: 1.32, 1.98); P < 0.0001], and when AST TAT was >63 h [OR:1.48 (95% CI: 1.16, 1.90); P = 0.0017]. Patients with carbapenem non-susceptible (carb-NS) ENT BSI had significantly higher LOS (16.6 days, 95% CI: 15.6, 17.8) compared to carbapenem susceptible (carb-S, 12.2 days, 95% CI: 11.8, 12.6), (P < 0.0001). Extended AST TAT was significantly associated with longer LOS for TAT of 57-65 h and >65 h (P = 0.005 and P< 0.0001, respectively) compared to TAT ≤42 h (reference). Inadequate empiric therapy (IET), carb-NS, and delayed AST TAT are significantly associated with adverse hospital outcomes in ENT BSI. Workflows that accelerate AST TAT for ENT BSIs and facilitate timely and adequate therapy may reduce post-BSI in-hospital mortality rate and LOS.IMPORTANCEFor patients diagnosed with bloodstream infections (BSI) caused by Enterobacterales (ENT), delayed time to antimicrobial susceptibility (AST) results can significantly impact in-hospital mortality and hospital length of stay. However, this relationship between time elapsed from blood culture collection to AST results has only been assessed, to date, in a limited number of publications. Our study focuses on this important gap using retrospective data from 29,570 blood ENT-positive admissions across 161 healthcare facilities in the US as we believe that a thorough understanding of the dynamic between AST turnaround time, adequacy of empiric therapy, post-BSI event mortality, and hospital length of stay will help guide effective clinical management and optimize outcomes of patients with ENT infections.

Organism-specific Trends in Carbapenem-resistant Enterobacterales Infections in a Cohort of Hospitalized Patients, 2012–2022

Background: Carbapenem-resistant Enterobacterales (CRE) infections are an urgent public health threat. An estimated 12,700 CRE (including E. coli, Klebsiella spp., and Enterobacter spp.) infections occurred in the United States in 2020. While the estimated incidence of CRE infections has been relatively stable between 2012 and 2020, organism-specific trends, including those for organisms not typically included in CRE surveillance definitions, have not been described. We estimated the annual rate of carbapenem-resistant Enterobacterales infections, disaggregated by organism, from 2012 to 2022. Methods: Data on inpatient hospitalizations from a dynamic cohort of short-term acute care hospitals reporting microbiology data between 2012 and 2022 were obtained from the PINC AI Database and the BD Insights Research Database. We included patients with clinical isolates of E. coli, Enterobacter spp., Klebsiella spp., Citrobacter spp., Serratia marcescens, Proteus mirabilis, and Morganella spp. and sufficient susceptibility results to identify carbapenem resistance. We limited our analysis to incident isolates, defined as a patient’s first isolate of a given organism and carbapenem resistance phenotype in a 14-day period. We calculated the annual rate of carbapenem-resistant infections per 10,000 hospitalizations for each organism. Results: There were 3,018,792 incident isolates from 55.8 million hospitalizations included in the analysis. Overall, 31,226 incident carbapenem-resistant isolates were identified. The rate of carbapenem-resistant infections varied by organism and over time (Table 1). The rate of carbapenem-resistant Klebsiella spp. infections appeared to decline from 3.94 in 2012 to 2.44 infections per 10,000 hospitalizations in 2022. The rate of carbapenem-resistant Enterobacter spp. infections appeared to increase from 1.05 in 2012 to 1.44 infections per 10,000 hospitalizations in 2022. The rate of carbapenem-resistant E. coli infections also appeared to increase, from 0.61 in 2012 to 0.85 infections per 10,000 hospitalizations in 2022. Rates of carbapenem-resistant Proteus mirabilis, Morganella spp., Citrobacter spp., or Serratia marcescens infections were similar in 2022 compared to 2012. Conclusions: Disaggregating data by organism revealed heterogeneous trends, with apparent increases in rates of carbapenem-resistant Enterobacter spp. and E. coli infections and apparent decreases in rates of carbapenem-resistant Klebsiella spp. infections. Organism-specific CRE analyses may provide additional insight into CRE epidemiology.

Development of a Simple Method to Detect the Carbapenemase-Producing Genes blaNDM, blaOXA-48-like, blaIMP, blaKPC, and blaVIM Using a LAMP Method with Lateral Flow DNA Chromatography.

Infections by carbapenemase-producing Enterobacterales constitute a global public health threat. The rapid and efficient diagnosis of Enterobacterales infection is critical for prompt treatment and infection control, especially in hospital settings. We developed a novel loop-mediated isothermal amplification (LAMP) method combined with DNA chromatography to identify five major groups of carbapenemase-producing genes (blaNDM, blaOXA-48-like, blaIMP, blaKPC, and blaVIM). This method uses DNA-DNA hybridization-based detection in which LAMP products can be easily visualized as colored lines. No specific technical expertise, expensive equipment, or special facilities are required for this method, allowing its broad application. Here, 73 bacteria collections including strains with carbapenemase-producing genes were tested. Compared to sequencing results, LAMP DNA chromatography for five carbapenemase-producing genes had a sensitivity and specificity of 100% and >97%, respectively. This newly developed method can be a valuable rapid diagnostic test to guide appropriate treatments and infection control measures, especially in resource-limited settings.

MultiRapid ATB NP test for detecting concomitant susceptibility and resistance of last-resort novel antibiotics available to treat multidrug-resistant Enterobacterales infections

BackgroundRecently developed therapeutics against Gram-negative bacteria include the β-lactam-β-lactamase inhibitor combinations ceftazidime–avibactam (CZA), meropenem–vaborbactam (MEV), and imipenem–relebatam (IPR), and the siderophore cephalosporin cefiderocol (FDC). The aim of this study was to develop a test for rapid identification of susceptibility/resistance to CZA, MEV, IPR, and FDC for Enterobacterales in a single test for rapid clinical decision making. MethodsThe MultiRapid ATB NP test is based on the detection of glucose metabolism occurring after bacterial growth in the presence of defined concentrations of CZA, MEV, IPR, and FDC, followed by visual detection of colour change of the pH indicator red phenol (red to yellow) generated by the acidification of the medium upon bacterial growth. This test is performed in 96-well microplates. The MultiRapid ATB NP test was evaluated using 78 Enterobacterales isolates and compared to the reference method broth microdilution. ResultsThe MultiRapid ATB NP test displayed 97.0% (confidence interval [CI] 92.6–98.8) sensitivity, 97.7% (CI 94.3–99.1) specificity, and 97.4% (CI 95.0–98.7) accuracy. The results were obtained after 3 h of incubation at 35 °C ± 2 °C, representing at least a 15-h gain-of-time compared with currently used antimicrobial susceptibility testing methods. ConclusionThe MultiRapid ATB NP test provided accurate results for the concomitant detection of susceptibility/resistance to CZA, MEV, IPR, and FDC in Enterobacterales, independent of the resistance mechanism. This test may be suitable for implementation in any microbiology routine laboratory.

Emergence of NDM-producing Enterobacterales infections in companion animals from Argentina

Antimicrobial resistance is considered one of the most critical threat for both human and animal health. Recently, reports of infection or colonization by carbapenemase-producing Enterobacterales in companion animals had been described. This study report the first molecular characterization of NDM-producing Enterobacterales causing infections in companion animals from Argentina. Nineteen out of 3662 Enterobacterales isolates analyzed between October 2021 and July 2022 were resistant to carbapenemes by VITEK2C and disk diffusion method, and suspected to be carbapenemase-producers. Ten isolates were recovered from canine and nine from feline animals. Isolates were identified as K. pneumoniae (n = 9), E. coli (n = 6) and E. cloacae complex (n = 4), and all of them presented positive synergy among EDTA and carbapenems disks, mCIM/eCIM indicative of metallo-carbapenemase production and were also positive by PCR for blaNDM gene. NDM variants were determined by Sanger sequencing method. All 19 isolates were resistant to β-lactams and aminoglycosides but remained susceptible to colistin (100%), tigecycline (95%), fosfomycin (84%), nitrofurantoin (63%), minocycline (58%), chloramphenicol (42%), doxycycline (21%), enrofloxacin (5%), ciprofloxacin (5%) and trimethoprim/sulfamethoxazole (5%). Almost all isolates (17/19) co-harbored blaCTX-M plus blaCMY, one harbored blaCTX-M alone and the remaining blaCMY. E. coli and E. cloacae complex isolates harbored blaCTX-M-1/15 or blaCTX-M-2 groups, while all K. pneumoniae harbored only blaCTX-M-1/15 genes. All E. coli and E. cloacae complex isolates harbored blaNDM-1, while in K. pneumoniae blaNDM-1 (n = 6), blaNDM-5 (n = 2), and blaNDM-1 plus blaNDM-5 (n = 1) were confirmed. MLST analysis revealed the following sequence types by species, K. pneumoniae: ST15 (n = 5), ST273 (n = 2), ST11, and ST29; E. coli: ST162 (n = 3), ST457, ST224, and ST1196; E. cloacae complex: ST171, ST286, ST544 and ST61. To the best of our knowledge, this is the first description of NDM-producing E. cloacae complex isolates recovered from cats. Even though different species and clones were observed, it is remarkable the finding of some major clones among K. pneumoniae and E. coli, as well as the circulation of NDM as the main carbapenemase. Surveillance in companion pets is needed to detect the spread of carbapenem-resistant Enterobacterales and to alert about the dissemination of these pathogens among pets and humans.

Carbapenem use in extended-spectrum cephalosporin-resistant Enterobacterales infections in US hospitals and influence of IDSA guidance: a retrospective cohort study

Disparate and rapidly changing practice recommendations from major professional infectious diseases societies for managing non-severe infections caused by extended-spectrum β-lactamase-producing Enterobacterales might hamper carbapenem stewardship. We aimed to understand the real-world management of extended-spectrum cephalosporin-resistant (ECR) Enterobacterales infections in US hospitals and factors influencing preference for carbapenems over alternative treatments. This retrospective cohort study included adults (aged ≥18 years) admitted to hospital with ECR Enterobacterales infections in the PINC AI database. Antibiotic regimens were assessed during empirical and targeted treatment periods and by infection severity and site. Likelihood of receiving targeted carbapenems over time and before or after initial release of the Infectious Diseases Society of America (IDSA) guidance on Sept 8, 2020, was established with generalised estimating equations controlling for patient, hospital, and temporal confounders. Between Jan 1, 2018, and Dec 31, 2021, 30 041 inpatient encounters with ECR Enterobacterales infections were identified at 168 US hospitals, of which 16 006 (53·3%) encounters were in women and 14 035 (46·7%) were in men, with a mean age of 67·3 years (SD 15·1). Although few patients received carbapenems empirically (5324 [17·7%] of 30 041), many did so as targeted treatment (17 518 [58·3%] of 30 041), including subgroups of patients without septic shock (3031 [45·6%] of 6651) and patients with urinary tract infections without septic shock (1845 [46·8%] of 3943) in whom specific narrower-spectrum alternatives were active. Transitions from non-carbapenem to carbapenem antibiotics occurred most often on the day that the ECR phenotype was reported, regardless of illness severity. Carbapenems were the predominant choice to treat ECR Enterobacterales infections over time (adjusted odds ratio 1·00 [95% CI 1·00-1·00]), with no additional immediate change (1·07 [0·95-1·20]) or sustained change (0·99 [0·98-1·00]) after IDSA guidance release. High carbapenem use in targeting non-severe ECR Enterobacterales infections in US hospitals predates 2020 IDSA guidance and has persisted thereafter. Efforts to increase awareness and implementation of recommendations among clinicians to use carbapenem-sparing alternatives in ECR Enterobacterales infections might decrease global carbapenem selective pressure. US National Institutes of Health Intramural Research Program, National Institute of Allergy and Infectious Diseases, and US Food and Drug Administration.

In vitro pharmacokinetics/pharmacodynamics of FL058 (a novel beta-lactamase inhibitor) combined with meropenem against carbapenemase-producing Enterobacterales.

Objective: FL058 is a novel beta-lactamase inhibitor with a broad spectrum of activity and a favorable safety profile. The objective of this study was to evaluate pharmacokinetic/pharmacodynamic (PK/PD) relationships for the combination of FL058 and meropenem in an in vitro infection model. Methods: By simulating human concentration-time profiles in the in vitro model, meropenem combined with FL058 when administered 1g/0.5 g, 1g/1g, 2g/1g, and 2g/2g q8h by 3-h infusion achieved approximately 2- and 4-log10 kill to KPC/OXA-producing Klebsiella pneumoniae and Escherichia coli; the combination therapy could not inhibit NDM-producing K. pneumoniae but could maintain NDM-producing E. coli around a baseline. Results: The PK/PD indexes that best described the bacterial killing from baseline in log10CFU/mL at 24h were the percent time of free drug above the minimal inhibitory concentration (MIC) (%fT > MIC, MIC with FL058 at 4mg/L) for meropenem and the percent time of free drug above 1mg/L (%fT > 1mg/L) for FL058. The targets for achieving a static effect and the 1- and 2-log10 kill were 74, 83, and 99 for %fT > MIC of meropenem and 40, 48, and 64 for %fT > 1mg/L of FL058, respectively. The PK/PD index of %fT > 1mg/L can provide a basis for evaluating clinical dosing regimens for FL058 combined with meropenem. Conclusion: FL058 combined with meropenem might be a potential treatment for KPC- and/or OXA-48-producing Enterobacterales infection.

Evaluation of the in vitro susceptibility of clinical isolates of NDM-producing Klebsiella pneumoniae to new antibiotics included in a treatment regimen for infections.

Due to the growing resistance to routinely used antibiotics, the search for new antibiotics or their combinations with effective inhibitors against multidrug-resistant microorganisms is ongoing. In our study, we assessed the in vitro drug susceptibility of Klebsiella pneumoniae strains producing New Delhi metallo-β-lactamases (NDM) to antibiotics included in the Infectious Diseases Society of America (IDSA) and European Society of Clinical Microbiology and Infectious Diseases (ESCMID) recommendations. A total of 60 strains of NDM-producing K. pneumoniae were obtained from different patients hospitalized at the 4th Military Hospital in Wroclaw between 2019 and 2022 and subjected to drug susceptibility to selected antibiotics, including the effects of drug combinations. Among the tested antibiotics, the highest sensitivity (100%) was observed for cefiderocol, eravacycline (interpreted according to the European Committee on Antimicrobial Susceptibility Testing [EUCAST]), and tigecycline. Sensitivity to intravenous fosfomycin varied depending on the method used. Using the "strip stacking" method, determining cumulative sensitivity to ceftazidime/avibactam and aztreonam demonstrated 100% in vitro sensitivity to this combination among the tested strains. The in vitro susceptibility assessment demonstrated that, the best therapeutic option for treating infections caused by carbapenemase-producing strains seems to be a combination of ceftazidime/avibactam with aztreonam. Due to the safety of using both drugs, cost effectiveness, and the broadest indications for use among the tested antibiotics, this therapy should be the first-line treatment for carbapenemase-producing Enterobacterales infections. Nevertheless, a comprehensive evaluation of the efficacy of treating infections caused by NDM-producing K. pneumoniae strains should include not only in vitro susceptibility assessment but also an analysis of clinical cases.

Clinical and genomic characteristics of IMP-producing Enterobacter cloacae complex and Klebsiella pneumoniae.

Carbapenemase-producing Enterobacterales (CPEs) are one of the top priority antimicrobial-resistant pathogens. Among CPEs, those producing acquired metallo-β-lactamases (MBLs) are considered particularly problematic as few agents are active against them. Imipenemase (IMP) is the most frequently encountered acquired MBL in Japan, but comprehensive assessment of clinical and microbiological features of IMP-producing Enterobacterales infection remains scarce. Here, we retrospectively evaluated 62 patients who were hospitalized at a university hospital in Japan and had IMP-producing Enterobacterales from a clinical culture. The isolates were either Enterobacter cloacae complex or Klebsiella pneumoniae, and most of them were isolated from sputum. The majority of K. pneumoniae, but not E. cloacae complex isolates, were susceptible to aztreonam. Sequence type (ST) 78 and ST517 were prevalent for E. cloacae complex and K. pneumoniae, respectively, and all isolates carried blaIMP-1. Twenty-four of the patients were deemed infected with IMP-producing Enterobacterales. Among the infected patients, therapy varied and largely consisted of conventional β-lactam agents, fluoroquinolones, or combinations. Three (13%), five (21%), and nine (38%) of them died by days 14, 30, and 90, respectively. While incremental mortality over 90 days was observed in association with underlying comorbidities, active conventional treatment options were available for most patients with IMP-producing Enterobacterales infections, distinguishing them from more multidrug-resistant CPE infections associated with globally common MBLs, such as New Delhi metallo-β-lactamase (NDM) and Verona integron-encoded metallo-β-lactamase (VIM).

Antimicrobial resistance in Enterobacterales infections among children in sub-Saharan Africa: a systematic review and meta-analysis

The burden of antimicrobial resistance (AMR) has been estimated to be the highest in sub-Saharan Africa (SSA). The current study estimated the proportion of drug-resistant Enterobacterales causing infections in SSA children. We searched MEDLINE/PubMed, Embase and the Cochrane Library to identify retrospective and prospective studies published from 01/01/2005 to 01/06/2022 reporting AMR of Enterobacterales causing infections in sub-Saharan children (0-18 years old). Studies were excluded if they had unclear documentation of antimicrobial susceptibility testing methods or fewer than ten observations per bacteria. Data extraction and quality appraisal were conducted by two authors independently. The primary outcome was the proportion of Enterobacterales resistant to antibiotics commonly used in paediatrics. Proportions were combined across studies using mixed-effects logistic regression models per bacteria and per antibiotic. Between-study heterogeneity was assessed using the I2 statistic. The protocol was registered with PROSPERO (CRD42021260157). After screening 1111 records, 122 relevant studies were included, providing data on more than 30,000 blood, urine and stool isolates. Escherichia coli and Klebsiella spp. were the predominant species, both presenting high proportions of resistance to third-generation cephalosporins, especially in blood cultures: 40.6% (95% CI: 27.7%-55%; I2: 85.7%, number of isolates (n): 1032) and 84.9% (72.8%-92.2%; I2: 94.1%, n: 2067), respectively. High proportions of resistance to other commonly used antibiotics were also observed. E.coli had high proportions of resistance, especially for ampicillin (92.5%; 95% CI: 76.4%-97.9%; I2: 89.8%, n: 888) and gentamicin (42.7%; 95% CI: 30%-56.5%; I2: 71.9%, n: 968). Gentamicin-resistant Klebsiella spp. were also frequently reported (77.6%; 95% CI: 65.5%-86.3%; I2: 91.6%, n: 1886). High proportions of resistance to antibiotics commonly used for empirical treatment of infectious syndromes were found for Enterobacterales in sub-Saharan children. There is a critical need to better identify local patterns of AMR to inform and update clinical guidelines for better treatment outcomes. No funding was received.

Real-time genomic epidemiologic investigation of a multispecies plasmid-associated hospital outbreak of NDM-5-producing Enterobacterales infections

New Delhi metallo-β-lactamase (NDM) is an emergent mechanism of carbapenem resistance associated with high mortality and limited treatment options. Because the blaNDM resistance gene is often carried on plasmids, traditional infection prevention and control (IP&C) surveillance methods and reactive whole genome sequencing (WGS) may not detect plasmid transfer in multispecies outbreaks. Initial outbreak detection of NDM-producing Enterobacterales identified at an acute care hospital occurred via traditional IP&C methods and was supplemented by real-time WGS surveillance performed weekly. To resolve NDM-encoding plasmids, we performed long-read sequencing and constructed hybrid assemblies. WGS data for suspected outbreaks was shared with the IP&C team for assessment and intervention. We observed a multispecies outbreak of NDM-5-producing Enterobacterales isolated from 15 patients between February 2021 and February 2023. The 19 clinical and surveillance isolates sequenced included 7 bacterial species encoding the same NDM-5 plasmid. WGS surveillance and epidemiologic investigation characterized 10 horizontal plasmid transfer events and 6 bacterial transmission events between patients in varying hospital units. Our investigation revealed a complex, multispecies outbreak of NDM involving multiple plasmid transfer and bacterial transmission events. We highlight the utility of combining traditional IP&C and prospective genomic methods in identifying and containing plasmid-associated outbreaks.

Gut microbiome dynamics and Enterobacterales infection in liver transplant recipients: A prospective observational study

Gut microbiome dynamics and Enterobacterales infection in liver transplant recipients: A prospective observational study

O01 Epidemiology and clinical characteristics of patients with carbapenem-resistant Enterobacterales infections: experience from a large tertiary care centre in a developing country

Abstract Background Carbapenem-resistant (CR) Enterobacterales (CREs) are a significant source of healthcare-associated infections. These bacteria are difficult to treat and have a high mortality rate due to high rates of antibiotic resistance. These pathogens are also linked to major outbreaks in healthcare institutions, especially those with limited resources in infection prevention and control. Objectives To describe the epidemiology and clinical characteristics of patients with carbapenem-resistant Enterobacteriaceae in a referral hospital in a developing country. Methods This was a retrospective cross-sectional study that included 218 patients admitted to An-Najah National University Hospital between 1 January 2021, and 31 May 2022. The target population was all patients with CRE infection or colonization in the hospital setting. Results Of the 218 patients, 135 had CR Klebsiella pneumoniae (61.9%) and 83 had CR Escherichia coli (38.1%). Of these, 135 were male (61.9%) and 83 were female (38.1%), with a median age of 51 years (IQR 24–64). Malignancy was a common comorbidity in 36.7% of the patients. Approximately 18.3% of CRE patients were obtained from patients upon admission to the emergency department, the largest percentage among departments. Most CRE pathogens were isolated from rectal swabs, accounting for 61.3%. Among the 218 patients, colistin was the most widely used antimicrobial agent (13.3%). CR E. coli showed resistance to amikacin in 23.8% of the pathogens tested and 85.7% for trimethoprim/sulfamethoxazole compared with CR K. pneumoniae, for which the resistance to trimethoprim/sulfamethoxazole was 74.1%, while for amikacin it was 64.2%. Regarding meropenem MIC, 85.7% of CR E. coli were greater than 16 mg/L compared with 84% of CR K. pneumoniae isolates. Conclusions This study found that CREs are frequently reported in this tertiary care setting, implying the presence of selective pressure and transmission associated with healthcare setting. The antibiotics tested showed a variety of resistance rates, with CR K. pneumoniae being more prevalent than CR E. coli and exhibiting an extremely high resistance pattern to the available therapeutic options.