Incidence of community-onset extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae infections: an 11-year population-based study in Denmark

Antibiotic resistance monitoring in wastewater in the Nordic countries: A systematic review

The Nordic countries (Denmark, Finland, Iceland, Norway, and Sweden) have effectively kept lower antibiotic-resistant bacterial (ARB) pathogen rates than many other countries. However, in recent years, these five countries have encountered a rise in ARB cases and challenges in treating infections due to the growing prevalence of ARB pathogens. Wastewater-based surveillance (WBS) is a valuable supplement to clinical methods for ARB surveillance, but there is a lack of comprehensive understanding of WBS application for ARB in the Nordic countries. This review aims to compile the latest state-of-the-art developments in WBS for ARB monitoring in the Nordic countries and compare them with clinical surveillance practices. After reviewing 1480 papers from the primary search, 54 were found relevant, and 15 additional WBS-related papers were included. Among 69 studies analyzed, 42 dedicated clinical epidemiology, while 27 focused on wastewater monitoring. The PRISMA review of the literature revealed that Nordic countries focus on four major WBS objectives of ARB: assessing ARB in the human population, identifying ARB evading wastewater treatment, quantifying removal rates, and evaluating potential ARB evolution during the treatment process. In both clinical and wastewater contexts, the most studied targets were pathogens producing carbapenemase and extended-spectrum beta-lactamase (ESBL), primarily Escherichia coli and Klebsiella spp. However, vancomycin-resistant Enterococcus (VRE) and methicillin-resistant Staphylococcus aureus (MRSA) have received more attention in clinical epidemiology than in wastewater studies, probably due to their lower detection rates in wastewater. Clinical surveillance has mostly used culturing, antibiotic susceptibility testing, and genotyping, but WBS employed PCR-based and metagenomics alongside culture-based techniques. Imported cases resulting from international travel and hospitalization abroad appear to have frequently contributed to the rise in ARB pathogen cases in these countries. The many similarities between the Nordic countries (e.g., knowledge exchange practices, antibiotic usage patterns, and the current ARB landscape) could facilitate collaborative efforts in developing and implementing WBS for ARB in population-level screening.

Association of piperacillin/tazobactam MIC and mortality in a cohort of ceftriaxone-resistant Escherichia coli bloodstream infections treated with piperacillin/tazobactam and carbapenems: a multicentric propensity score-weighted observational cohort study

OBJECTIVES

To assess the impact of piperacillin/tazobactam MICs on in-hospital 30 day mortality in patients with third-generation cephalosporin-resistant Escherichia coli bloodstream infection treated with piperacillin/tazobactam, compared with those treated with carbapenems.

METHODS

A multicentre retrospective cohort study was conducted in three large academic hospitals in Italy between 2018 and 2022. The study population comprised patients with monomicrobial third-generation cephalosporin-resistant E. coli bloodstream infection, who received either piperacillin/tazobactam or carbapenem therapy within 48 h of blood culture collection. The primary outcome was in-hospital 30 day all-cause mortality. A propensity score was used to estimate the likelihood of receiving empirical piperacillin/tazobactam treatment. Cox regression models were performed to ascertain risk factors independently associated with in-hospital 30 day mortality.

RESULTS

Of the 412 consecutive patients included in the study, 51% received empirical therapy with piperacillin/tazobactam, while 49% received carbapenem therapy. In the propensity-adjusted multiple Cox model, the Pitt bacteraemia score [HR 1.38 (95% CI, 0.85-2.16)] and piperacillin/tazobactam MICs of 8 mg/L [HR 2.35 (95% CI, 1.35-3.95)] and ≥16 mg/L [HR 3.69 (95% CI, 1.86-6.91)] were significantly associated with increased in-hospital 30 day mortality, while the empirical use of piperacillin/tazobactam was not found to predict in-hospital 30 day mortality [HR 1.38 (95% CI, 0.85-2.16)].

CONCLUSIONS

Piperacillin/tazobactam use might not be associated with increased mortality in treating third-generation cephalosporin-resistant E. coli bloodstream infections when the MIC is <8 mg/L.

Temporal changes in incidence of hospital-diagnosed acute pyelonephritis: A 19-year population-based Danish cohort study

Objectives

To examine temporal changes in the incidence of hospital-diagnosed acute pyelonephritis (APN) and characterize associated demographics.

Methods

Cohort study including Danish patients with hospital-diagnosed APN during 2000-2018, identified by International Classification of Diseases, 10th Revision codes. Annual sex- and age-standardized incidence rates per 10,000 person years with 95% confidence intervals (CIs) were stratified by sex, age group, diagnosis code, and region of residence. Incidence rates for selected urinary tract infections and sepsis diagnoses were also computed.

Results

We included 66,937 hospital-diagnosed APN episodes in 57,162 patients. From 2000 to 2018, the incidence increased from 6.8 (95% CI: 6.8-6.8) to 15.4 (95% CI: 15.4-15.4) in women and from 2.7 (95% CI: 2.7-2.7) to 4.5 (95% CI: 4.5-4.5) in men. Among infants, the rate rose from 7.4 (95% CI: 7.4-7.4) to 64.8 (95% CI: 64.7-64.9) in girls and from 17.1 (95% CI: 17.1-17.2) to 52.5 (95% CI: 52.4-52.6) in boys. Concomitant declines were observed in incidences of hospital-diagnosed unspecified urinary tract infections and sepsis.

Conclusion

The APN incidence roughly doubled during 2000-2018. The increase was largely driven by a prominently increasing incidence among young children which was not explained by the enlarging prevalence of congenital anomalies of the kidney and urinary tract.

Complement killing of clinical Klebsiella pneumoniae isolates is serum concentration dependent

Klebsiella pneumoniae is an opportunistic gram-negative pathogen causing serious infections, including sepsis. In plasma, activation of the complement cascades is important for killing bacteria. Thirty clinical Klebsiella spp. blood isolates were analyzed for serum susceptibility in 75% normal human serum (NHS). Twenty-two were serum resistant and eight were serum sensitive, and subsequently tested in 5-75% NHS. Two isolates were killed in 5% and the remaining six in 50%-75% NHS. The two 5% sensitive isolates showed binding of complement (C)4 and C3 in 5% NHS with formation of membrane attack complex (MAC). Inhibition of the classical/lectin mediated pathways (CP/LP) using a C4 specific nanobody, hC4Nb8, led to survival of both isolates in 5% NHS. Using nanobody hC3Nb1, inhibiting the alternative pathway (AP), the isolates were killed in 5% NHS, and amplification of the CP/LP by AP was not necessary for killing. Sole AP killing of these isolates when inhibiting CP/LP with hC4Nb8 was observed in 50% NHS, stressing the concentration dependent functionality of AP. For the less sensitive isolates, killing required activation of CP/LP and AP demonstrated by inhibition with nanobodies. AP inhibition resulted in no C3 deposition on the serum resistant isolate, supporting that AP was the sole activation pathway.

Current Stage in the Development of Klebsiella pneumoniae Vaccines

Klebsiella pneumoniae is a bacterium capable of colonizing mucous membranes, causing serious infections. Widespread antibiotic resistance in K. pneumoniae—either through intrinsic mechanisms or via acquisition from different species, especially in hospital environments—limits the therapeutic options against this pathogen, further aggravating the disease burden. To date, there are no vaccines available against K. pneumoniae infection. Although formulations based on capsular polysaccharides have been proposed, the high variability in capsular serotypes limits vaccine coverage. Recombinant vaccines based on surface exposed bacterial antigens are a promising alternative owing to their conservation among different serotypes and accessibility to the immune system. Many vaccine candidates have been proposed, some of which have reached clinical trials. The present review summarizes the current status of K. pneumoniae vaccine development. Different strategies including whole cell vaccines, outer membrane vesicles (OMVs), ribosome, polysaccharide, lipopolysaccharide (LPS), and protein-based formulations are discussed. The contribution of antibody and cell-mediated responses is also presented. In summary, K. pneumoniae vaccines are feasible and a promising strategy to prevent infections and to reduce the antimicrobial resistance burden worldwide.

High Prevalence of Extended-Spectrum Beta-Lactamases in Escherichia coli Strains Collected From Strictly Defined Community-Acquired Urinary Tract Infections in Adults in China: A Multicenter Prospective Clinical Microbiological and Molecular Study

Objective

The objective of the study was to investigate the antimicrobial susceptibility and extended-spectrum beta-lactamase (ESBL) positive rates of Escherichia coli from community-acquired urinary tract infections (CA-UTIs) in Chinese hospitals.

Materials and Methods

A total of 809 E. coli isolates from CA-UTIs in 10 hospitals (5 tertiary and 5 secondary hospitals) from different regions in China were collected during the period 2016–2017 according to the strict inclusion criteria. Antimicrobial susceptibility testing was carried out by standard broth microdilution method. Isolates were categorized as ESBL-positive, ESBL-negative, and ESBL-uncertain groups according to the CLSI recommended phenotypic screening method. ESBL and AmpC genes were amplified and sequenced on ESBL-positive and ESBL-uncertain isolates.

Results

The antimicrobial agents with susceptibility rates of greater than 95% included imipenem (99.9%), colistin (99.6%), ertapenem (98.9%), amikacin (98.3%), cefmetazole (97.9%), nitrofurantoin (96%), and fosfomycin (95.4%). However, susceptibilities to cephalosporins (varying from 58.6% to 74.9%) and levofloxacin (48.8%) were relatively low. In the phenotypic detection of ESBLs, ESBL-positive isolates made up 38.07% of E. coli strains isolated from CA-UTIs, while 2.97% were ESBL-uncertain. Antimicrobial susceptibilities of imipenem, cefmetazole, colistin, ertapenem, amikacin, and nitrofurantoin against ESBL-producing E. coli strains were greater than 90%. The percentage of ESBL-producing strains was higher in male (53.6%) than in female patients (35.2%) (p < 0.001). CTX-M-14 (31.8%) was the major CTX-M variant in the ESBL-producing E. coli, followed by CTX-M-55 (23.4%), CTX-M-15 (17.5%), and CTX-M-27 (13.3%). The prevalence of carbapenem-resistant E. coli among CA-UTI isolates was 0.25% (2/809).

Conclusion

Our study indicated high prevalence of ESBL in E. coli strains from strictly defined community-acquired urinary tract infections in adults in China. Imipenem, colistin, ertapenem, amikacin, and nitrofurantoin were the most active antimicrobials against ESBL-positive E. coli isolates. bla_CTX–M–14 is the predominant esbl gene in ESBL-producing and ESBL-uncertain strains. Our study indicated that the use of cephalosporins and fluoroquinolone needs to be restricted for empirical treatment of CA-UTIs in China.

Outcome of community-onset ESBL-producing Escherichia coli and Klebsiella pneumoniae bacteraemia and urinary tract infection: a population-based cohort study in Denmark

OBJECTIVES

To assess the impact of ESBL production on mortality and length of hospital stay (LOS) of community-onset infections due to Escherichia coli or Klebsiella pneumoniae.

METHODS

A population-based cohort study including all adult patients hospitalized with a first-time community-onset E. coli or K. pneumoniae bacteraemia or urinary tract infection in the North Denmark Region between 2007 and 2017. For each bacterial agent, we computed 1 year Kaplan-Meier survival curves and cumulative incidence functions of LOS, and by use of Cox proportional hazard regression we computed HRs as estimates of 30 day and 1 year mortality rate ratios (MRRs) and LOS among patients with and without ESBL-producing infections.

RESULTS

We included 24 518 cases (among 22350 unique patients), of whom 1018 (4.2%) were infected by an ESBL-producing bacterium. The 30 day cumulative mortality and adjusted MRR (aMRR) in patients with and without ESBL-producing isolates was as follows: E. coli bacteraemia (n = 3831), 15.8% versus 14.0%, aMRR = 1.01 (95% CI = 0.70-1.45); E. coli urinary tract infection (n = 17151), 9.5% versus 8.7%, aMRR = 0.97 (95% CI = 0.75-1.26); K. pneumoniae bacteraemia (n = 734), 0% versus 17.2%, aMRR = not applicable; and K. pneumoniae urinary tract infection (n = 2802), 13.8% versus 10.7%, aMRR = 1.13 (95% CI = 0.73-1.75). The 1 year aMRR remained roughly unchanged. ESBL-producing E. coli bacteraemia was associated with an increased LOS compared with non-ESBL production.

CONCLUSIONS

ESBL production was not associated with an increased short- or long-term mortality in community-onset infections due to E. coli or K. pneumoniae, yet ESBL-producing E. coli bacteraemia was associated with an increased LOS.

Bacterial and fungal bloodstream infections in pediatric liver and kidney transplant recipients

Background

Bacterial and fungal bloodstream infections (BSI) are common after pediatric liver and kidney transplantations and associated with morbidity and mortality. However, knowledge about incidence rates, pathogen composition, and resistance patterns is limited. We aimed to describe the pattern of bacterial and fungal BSI in a cohort of pediatric liver and kidney transplant recipients.

Methods

A prospective study of 85 pediatric liver and kidney transplant recipients transplanted from 2010 to 2017 with a total of 390 person-years of follow-up. Clinical characteristics and BSI were retrieved from national registries assuring nationwide follow-up for at least 1 year. BSI incidence rates and pathogen composition were investigated and stratified by the time post-transplantation and type of transplanted organ.

Results

A total of 29 BSI were observed within the first 5 years post-transplantation with 16 different pathogens. The overall incidence rate of first BSI was 1.91 per 100 recipients per month (95% CI, 1.1–3.1) in the first year post-transplantation. The most common pathogens were Enterococcus faecium, Candida albicans, Escherichia coli, and Klebsiella pneumoniae. The pathogen composition depended on the transplanted organ with a higher proportion of BSI with Enterobacterales in kidney transplant recipients than in liver transplant recipients (67% vs. 20%, p = 0.03), while multiple pathogens were detected in the liver transplant recipients.

Conclusions

BSI were common in pediatric liver and kidney transplant recipients and the pathogen composition differed between liver and kidney transplant recipients. Guidelines for empiric antibiotic therapy should consider the type of transplanted organ as well as the local resistance patterns.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06224-2.

Clinical and Economic Impact of Community-Onset Urinary Tract Infections Caused by ESBL-Producing Klebsiella pneumoniae Requiring Hospitalization in Spain: An Observational Cohort Study

Objective: To analyze the clinical and economic impact of community-onset urinary tract infections (UTIs) caused by extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae requiring hospitalization. Methods: A retrospective cohort study that included all adults with a UTI caused by K. pneumoniae that were admitted to a tertiary care hospital in Barcelona, Spain, between 2011 and 2015. Demographic, clinical, and economic data were analyzed. Results: One hundred and seventy-three episodes of UTIs caused by K. pneumoniae were studied; 112 were non-ESBL-producing and 61 were ESBL-producing. Multivariate analysis identified ESBL production, acute confusional state associated with UTI, shock, and the time taken to obtain adequate treatment as risk factors for clinical failure during the first seven days. An economic analysis showed differences between ESBL-producing and non-ESBL-producing K. pneumoniae for the total cost of hospitalization per episode (mean EUR 6718 vs EUR 3688, respectively). Multivariate analysis of the higher costs of UTI episodes found statistically significant differences for ESBL production and the time taken to obtain adequate treatment. Conclusion: UTIs caused by ESBL-producing K. pneumoniae requiring hospitalization and the time taken to obtain adequate antimicrobial therapy are associated with worse clinical and economic outcomes.

Analysis of patterns of bacteremia and 30-day mortality in patients with acute cholangitis over a 25-year period

INTRODUCTION

Acute cholangitis (AC) is a condition of bacterial infection in the biliary tract with a high mortality rate of around 10%. Direct association between presence of bacteremia and 30-day mortality among AC patients is sparsely investigated and remains unclear.

AIMS AND METHODS

Our aim was to investigate association between bacteremia and 30-day mortality among patients with AC included over a period of 25 years. All AC patients that underwent endoscopic retrograde cholangiopancreatography (ERCP) at Odense University Hospital, between 1 January 1990 and 31 October 2015, were identified using a prospective ERCP database. Blood culture results from the patients along with antimicrobial resistance patterns were collected from a bacteremia research database.

RESULTS

During the study period, 775 consecutive AC patients underwent ERCP and blood cultures were collected from 528 patients. Among these patients 48% (n = 260) had bacteremia. Overall, 30-day mortality in patients with blood cultures performed was 13% (n = 69). In patients with bacteremia, 30-day mortality was 19% (n = 49), compared to 7% (n = 20) in patients without bacteremia (p < .01). Presence of bacteremia was associated with increased 30-day mortality (OR [95% CI]: 3.43 [1.92-6.13]; p < .01) following adjustment for confounding factors. Among the species, bacteremia with Enterobacter cloacae was significantly associated with increased 30-day mortality (OR [95% CI]: 2.97 [1.16-7.62]; p = .02).

CONCLUSION

Our results indicate that presence of bacteremia was associated with a nearly fourfold increase in 30-day mortality among AC patients.

Risk factors of community-onset extended-spectrum β-lactamase Escherichia coli and Klebsiella pneumoniae bacteraemia: an 11-year population-based case-control-control study in Denmark

OBJECTIVES

To investigate and explore temporal changes in risk factors of community-onset extended-spectrum β-lactamase (ESBL) Escherichia coli and Klebsiella pneumoniae bacteraemia in a region with low antibiotic resistance.

METHODS

Population-based case-control study including 223 cases hospitalized with a first-time community-onset ESBL-producing E. coli and K. pneumoniae bacteraemia, 2214 non-ESBL E. coli and K. pneumoniae bacteraemia controls, and 2228 population controls in the North Denmark Region between 2007 and 2017. We used a conditional logistic regression to compute crude and adjusted (age, gender and co-morbidity) odds ratios (aORs) and 95% CIs of risk factors and compared selected risk factors between 2007-2011 and 2016-2017.

RESULTS

Several conventional risk factors of ESBL E. coli or K. pneumoniae were identified compared with the population controls. Compared with the non-ESBL controls, use of fluoroquinolones (aOR 3.56, 95% CI 2.52-5.05), three or more admissions within the recent year (aOR 2.18, 95% CI 1.45-3.28), three or more antibiotic prescriptions within 15-365 days before the admission (aOR 2.18, 95% CI 1.53-3.10), male sex (aOR 2.01, 95% CI 1.50-2.69), admission within 1-91 days (aOR 1.84, 95% CI 1.37-2.48) and antibiotic within 15-91 days (aOR 1.82, 95% CI 1.37-2.42) inferred the highest risk. Assessment of temporal dynamics between 2007-2011 and 2016-2017 revealed a slight reduction in risk factors associated with direct health-care contact (e.g. hospital admission).

CONCLUSIONS

Recent and frequent hospitalization, and exposure to antibiotics, especially use of fluoroquinolones, appeared to be associated specifically with ESBL production, and focus and interventions should be directed towards these areas. Our results indicated a dissemination of ESBLs into the community.