Association between Timing of Colonization and Risk of Developing Klebsiella pneumoniae Carbapenemase-Producing K. pneumoniae Infection in Hospitalized Patients

Relative faecal abundance to predict extended-spectrum β-lactamase-producing Enterobacterales related ventilator‑associated pneumonia

BACKGROUND

Antimicrobial stewardship (AMS) for ventilator-associated pneumonia (VAP) in carriers of extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E) presents significant challenges. The abundance of ESBL-E rectal carriage has emerged as a potentially valuable tool for predicting ESBL-E-related VAP.

METHODS

This single-center, retrospective study was conducted between October 2019 and April 2023 in the medical ICU of a university hospital. The relative abundance of ESBL-E rectal carriage (RAC) was calculated as the ratio of ESBL-E counts to the total number of aerotolerant bacteria. The aim was to evaluate the predictive value of RAC for diagnosing ESBL-E-related VAP in patients with confirmed VAP who were ESBL-E carriers.

RESULTS

During the study period, 478 patients with ESBL-E carriage were admitted to the ICU, of whom 231 (48%) required mechanical ventilation. Eighty-three patients (17%) developed a total of 131 confirmed VAP episodes, of which 62 episodes (47%) were ESBL-E-related VAP. The median interval between the last rectal screening and VAP occurrence was 4 [3-7] days. RAC was not associated with ESBL-E-related VAP in the entire cohort (p = 0.39). Similar findings were observed in several sensitivity analyses, including the following subsets: recent and high-quality screening (interval between screening and VAP ≤ 7 days and bacterial load on rectal swab > 104 CFU/mL, p = 0.21); first VAP episodes only (p = 0.41); cases involving Escherichia coli exclusively (p = 0.08) or other ESBL-E strains (p = 0.29); and VAP associated with Gram-negative bacteria (p = 0.26) or Enterobacterales (p = 0.34). However, in a multivariable model, rectal colonization with non-Escherichia coli ESBL strains was independently associated with ESBL-E-related VAP (adjusted odds ratio [aOR] 1.213 [95% CI 1.005-1.463], p = 0.045).

CONCLUSION

RAC was not associated with confirmed VAP in ESBL-E carriers. Further studies are needed to explore effective strategies for improving AMS in ESBL-E carriers with suspected VAP.

Real-life use of temocillin in the treatment of bone and joint infections due to extended spectrum β-lactamase-producing Enterobacterales

Objectives

The aim of this study is to describe the real-life use of temocillin in bone and joint infections (BJI).

Patients and methods

We performed a monocentric retrospective study, including all patients treated by temocillin for a BJI due to extended spectrum β-lactamase-producing Enterobacterales (ESBL-E) between 1 January 2015 and 31 December 2022. Outcomes were evaluated at least 3 months after the end of antimicrobial treatment. Clinical cure was defined as the absence of recurrence of BJI during follow-up among patients who completed at least 7 days of temocillin. If the patient discontinued temocillin due to ineffectiveness, the outcome was considered to be unfavourable. Seventeen patients were treated with temocillin for ESBL-E associated BJI during the study period.

Results

Infections included osteomyelitis of the foot (7/17; 41.2%), femoral osteomyelitis (4/17; 23.5%), disco-vertebral infections (2/17; 11.8%), total knee prosthesis infections (2/17; 11.8%) and total hip prosthesis infections (2/17; 11.8%). All patients except one (n = 16) had surgical management of the infection. The main bacteria identified were the Enterobacter cloacae complex (n = 9) and Klebsiella pneumoniae (n = 5). The median daily dose was 6 g for a median duration of 42 days (IQR 14-42 days). The median duration of follow-up was 12 months (IQR 5.25-14.5). Overall, 12 patients completed at least 3 months of follow-up, and clinical cure was observed in eight of them (8/12; 66.7%).

Conclusion

So far, this is the first report of BJI successfully treated with temocillin. This suggests that temocillin may be an alternative to treat BJI involving difficult-to-treat Enterobacterales when oral therapy is not available.

Epidemiology of subsequent carbapenem-resistant enterobacterales (CRE) infection among rectal carriers: A meta-analysis of incidence, risk factors and their association with geographic region and age

BACKGROUND

This study aimed to assess the incidence and risk factors of subsequent carbapenem-resistant Enterobacterales (CRE) infection among rectal carriers, and their association with geographic region and age.

METHODS

A meta-analysis of studies investigating incidence and/or risk factors of subsequent CRE infection among rectal carriers was conducted, with subgroup analyses by geographic region and age. PubMed, Embase, Web of Science, and Cochrane Library were searched (published from inception to 31 January 2024). This study is registered with PROSPERO (CRD42023444420).

RESULTS

Of 4459 studies identified, 24 studies with 8188 CRE rectal carriers were included. The pooled incidence of subsequent CRE infection was 20.6% (95% CI 15.9-25.8). The highest incidence was seen in America (23.6%, 95% CI 14.2-34.5), followed by Europe (20.9%, 95% CI 12.5-30.8) and Asia (19.8%, 95% CI 12.7-27.9). Children had a greater incidence (26.7%, 95% CI 21.3-32.3) than adults (19.8%, 95% CI 14.9-25.2). Fourteen factors were associated with subsequent CRE infection. In Asia, the most notable risk factor was gastritis (odds ratio [OR] 4.95 95% CI 1.87-13.11). In Europe, admission to the intensive care unit was prominent (OR 2.76 95% CI 1.14-6.65). In the America, the use of a urinary Foley catheter (OR 4.33 95% CI 1.06-17.70) was dominant. Admission to the intensive care unit was most notable in adults (OR 3.01 95% CI 1.80-5.02), while mechanical ventilation was shown the greatest significance in children (OR 15.61 95% CI 4.39-55.47).

CONCLUSIONS

Risk of subsequent CRE infection among rectal carriers was critical. Identifying the risk factors for subsequent infection could help in developing more potent prevention and control measures to reduce CRE infection.

Biliary pharmacokinetic/pharmacodynamic analysis of continuous infusion meropenem/vaborbactam in a case series of orthotopic liver transplant recipients

OBJECTIVE

To analyse the biliary pharmacokinetics/pharmacodynamics (PK/PD) of continuous infusion (CI) meropenem-vaborbactam (MEM-VBM) in a case series of orthotopic liver transplant (OLT) recipients being treated for Klebsiella pneumoniae carbapenemase-producing Klebsiella pneumoniae (KPC-Kp) related biliary tract infections (BTIs) or as preemptive therapy of KPC-Kp rectal colonization.

METHODS

Critical OLT recipients receiving CI MEM-VBM (2 g/2 g q8h over 8 h) because of KPC-Kp related BTIs or as preemptive therapy of KPC-Kp rectal colonization, having Kehr's tube positioned and undergoing simultaneous therapeutic drug monitoring of MEM and VBM in plasma and bile were retrospectively assessed. Bile-to-plasma ratio of free steady-state concentrations (fCss) of MEM and VBM was used for assessing biliary penetration. Optimal joint MEM-VBM PK/PD target attainment was defined as MEM fCss/MIC ratio >4 coupled with VBM free area under time-concentration curve (fAUC)/threshold concentration (CT) ratio >24.

RESULTS

Overall, four critical OLT recipients were included. Median bile-to-plasma ratio was 0.32 for MEM (range 0.21-0.79) and 0.40 for VBM (range 0.20-0.77). Biliary MEM-VBM joint PK/PD target attainment was optimal in 3/4 OLT recipients and quasi-optimal in the other one.

CONCLUSIONS

The 1:1 proportion between MEM and VBM concentrations was maintained unchanged in the bile, allowing us to assume that the efficacy of MEM-VBM may be appropriate even in the treatment of BTIs. CI administration was an effective strategy for attaining aggressive biliary joint PK/PD targets against pathogens with an MIC up to 2 mg/L.

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

BACKGROUND

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).

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

The correlation between intestinal colonization and infection of carbapenem-resistant Klebsiella pneumoniae: A systematic review

As a widely spread Gram-negative bacteria, Klebsiella pneumoniae (KP) mainly causes acquired infections in hospitals, such as lung infections, urinary tract infections, and bloodstream infections. In recent years, the number of multidrug-resistant KP strains has increased dramatically, posing a great threat to human health. Carbapenem-resistant KP (CRKP) can be colonized in human body, especially in gastrointestinal tract, and some colonized patients can be infected during hospitalization, among which invasive operation, underlying disease, admission to intensive care unit, antibiotic use, severity of the primary disease, advanced age, operation, coma, and renal failure are common risk factors for secondary infection. Active screening and preventive measures can effectively prevent the occurrence of CRKP infection. Based on the epidemiological status, this study aims to discuss the correlation between colonization and secondary infection induced by CRKP and risk factors for their happening and provide some reference for nosocomial infection prevention and control.

The Natural History of Carbapenemase-Producing Enterobacterales: Progression From Carriage of Various Carbapenemases to Bloodstream Infection

BACKGROUND

Little is known about the risk of progression from carbapenemase-producing Enterobacterales (CPE) carriage to CPE bloodstream infection (BSI) outside of high-risk settings. We aimed to determine the incidence of CPE BSI among CPE carriers and to assess whether the incidence differs by carbapenemase, species, and setting.

METHODS

We conducted a nationwide population-based retrospective cohort study using national databases. The cohort consisted of all patients in Israel with CPE detected by screening from 1 January 2020 to 10 October 2022. We calculated the cumulative incidence of CPE BSI within 1 year among CPE carriers. We used a competing-risks model with BSI as the outcome and death as the competing risk.

RESULTS

The study included 6828 CPE carriers. The cumulative incidence of CPE BSI was 2.4% (95% confidence interval [CI], 2.1-2.8). Compared with Klebsiella pneumoniae carbapenemase (KPC), the subhazard of BSI was lower for New Delhi metallo-β-lactamase (NDM) (adjusted subhazard ratio [aSHR], 0.72; 95% CI, .49-1.05) and oxacillinase-48-like (OXA-48-like) (aSHR, 0.60; 95% CI, .32-1.12) but these differences did not reach statistical significance. Compared with K. pneumoniae, the subhazard of BSI was lower for carriers of carbapenemase-producing Escherichia coli (aSHR, 0.33; 95% CI, .21-.52). The subhazard of BSI was higher among patients with CPE carriage first detected in intensive care units (aSHR, 2.10; 95% CI, 1.27-3.49) or oncology/hematology wards (aSHR, 3.95; 95% CI, 2.51-6.22) compared with medical wards.

CONCLUSIONS

The risk of CPE BSI among CPE carriers is lower than previously reported in studies that focused on high-risk patients and settings. The risk of BSI differs significantly by bacterial species and setting, but not by carbapenemase.

Incidence and risk factors for subsequent infections among rectal carriers with carbapenem-resistant Klebsiella pneumoniae: a systematic review and meta-analysis

BACKGROUND

Carbapenem-resistant Klebsiella pneumoniae (CRKp) is a major pathogen causing nosocomial infections with a high mortality and poor prognosis. Gastrointestinal carriage has been acknowledged as the primary reservoir of CRKp infections.

AIM

To explore the incidence and risk factors associated with CRKp infection following colonization.

METHODS

The PubMed, Web of Science, and Cochrane Library databases were searched for relevant articles published between December 1998 and June 2023. Pooled estimates with a 95% confidence interval (CI) were calculated for the incidence rate, whereas pooled odds ratios (ORs) were calculated for the risk factors for which the OR was reported in three or more studies.

FINDINGS

Fourteen studies were included in the review with 5483 patients for the assessment of incidence, whereas seven of these studies with 2170 patients were included for the analysis of risk factors. In the meta-analysis, the incidence of CRKp infections after colonization was 23.2% (17.9-28.5). Additionally, three independent risk factors for subsequent CRKp infections were identified as admission to the intensive care unit (ICU) (2.59; 95% CI: 1.64-4.11), invasive procedures (2.53; 95% CI: 1.59-4.03), and multi-site colonization (6.24; 95% CI: 2.38-16.33).

CONCLUSION

This review reveals the incidence of CRKp infections in rectal carriers in different countries, emphasizing the role of rectal colonization with CRKp as an important source of nosocomial infections. Significantly, the risk factors indicated in this review can assist clinicians in identifying CRKp carriers with an elevated risk of subsequent infections, thereby enabling further measures to be taken to prevent nosocomial infections.

The ICU-CARB score: a novel clinical scoring system to predict carbapenem-resistant gram-negative bacteria carriage in critically ill patients upon ICU admission

BACKGROUND

With the widespread spread of carbapenem-resistant gram-negative bacteria (CR-GNB) in medical facilities, the carriage of CR-GNB among critically ill patients has become a significant concern in intensive care units (ICU). This study aimed to develop a scoring system to identify CR-GNB carriers upon ICU admission.

METHODS

Consecutive critically ill patients admitted to the ICU of Shanghai Ruijin Hospital between January 2017 and December 2020 were included. The patients were then divided into training and testing datasets at a 7:3 ratio. Parameters associated with CR-GNB carriage were identified using least absolute shrinkage and selection operator regression analysis. Each parameter was assigned a numerical score ranging from 0 to 100 using logistic regression analysis. Subsequently, a four-tier risk-level system was developed based on the cumulative scores, and assessed using the area under the receiver operating characteristic curve (AUC).

RESULTS

Of the 1736 patients included in this study, the prevalence of CR-GNB carriage was 10.60%. The clinical scoring system including seven variables (neurological disease, high-risk department history, length of stay ≥ 14 days, ICU history, invasive mechanical ventilation, gastrointestinal tube placement, and carbapenem usage) exhibited promising predictive capabilities. Patients were then stratified using the scoring system, resulting in CR-GNB carriage rates of 2.4%, 12.0%, 36.1%, and 57.9% at the respective risk levels (P < 0.001). Furthermore, the AUC of the developed model in the training set was calculated to be 0.82 (95% CI, 0.78-0.86), while internal validation yielded an AUC of 0.83 (95% CI, 0.77-0.89).

CONCLUSIONS

The ICU-CARB Score serves as a straightforward and precise tool that enables prompt evaluation of the risk of CR-GNB carriage at the time of ICU admission, thereby facilitating the timely implementation of targeted pre-emptive isolation.

Natera A, Recio-Rufián M, Guzmán-Puche J, Marín-Sanz JA, Martín-Pérez C, Cano Á, Castón JJ, Elías-López C, Machuca I, Gutiérrez-Gutiérrez B, Martínez-Martínez L, Torre-Cisneros J. Prognostic Significance of the Relative Load of KPC-Producing Klebsiella pneumoniae within the Intestinal Microbiota in a Prospective Cohort of Colonized Patients

Increased relative bacterial load of KPC-producing Klebsiella pneumoniae (KPC-KP) within the intestinal microbiota has been associated with KPC-KP bacteremia. Prospective observational study of KPC-KP adult carriers with a hospital admission at recruitment or within the three prior months (January 2018 to February 2019). A qPCR-based assay was developed to measure the relative load of KPC-KP in rectal swabs (RLKPC, proportion of blaKPC relative to 16S rRNA gene copy number). We generated Fine-Gray competing risk and Cox regression models for survival analysis of all-site KPC-KP infection and all-cause mortality, respectively, at 90 and 30 days. The median RLKPC at baseline among 80 KPC-KP adult carriers was 0.28% (range 0.001% to 2.70%). Giannella Risk Score (GRS) was independently associated with 90-day and 30-day all-site infection (adjusted subdistribution hazard ratio [aHR] 1.23, 95% CI = 1.15 to 1.32, P < 0.001). RLKPC (adjusted hazard ratio [aHR] 1.04, 95% CI = 1.01 to 1.07, P = 0.008) and age (aHR 1.05, 95% CI = 1.01 to 1.10, P = 0.008) were independent predictors of 90-day all-cause mortality in a Cox model stratified by length of hospital stay (LOHS) ≥20 days. An adjusted Cox model for 30-day all-cause mortality, stratified by LOHS ≥14 days, included RLKPC (aHR 1.03, 95% CI = 1.00 to 1.06, P = 0.027), age (aHR 1.10, 95% CI = 1.03 to 1.18, P = 0.004), and severe KPC-KP infection (INCREMENT-CPE score >7, aHR 2.96, 95% CI = 0.97 to 9.07, P = 0.057). KPC-KP relative intestinal load was independently associated with all-cause mortality in our clinical setting, after adjusting for age and severe KPC-KP infection. Our study confirms the utility of GRS to predict infection risk in patients colonized by KPC-KP. IMPORTANCE The rapid dissemination of carbapenemase-producing Enterobacterales represents a global public health threat. Increased relative load of KPC-producing Klebsiella pneumoniae (KPC-KP) within the intestinal microbiota has been associated with an increased risk of bloodstream infection by KPC-KP. We developed a qPCR assay for quantification of the relative KPC-KP intestinal load (RLKPC) in 80 colonized patients and examined its association with subsequent all-site KPC-KP infection and all-cause mortality within 90 days. Giannella Risk Score, which predicts infection risk in colonized patients, was independently associated with the development of all-site KPC-KP infection. RLKPC was not associated with all-site KPC-KP infection, possibly reflecting the large heterogeneity in patient clinical conditions and infection types. RLKPC was an independent predictor of all-cause mortality within 90 and 30 days in our clinical setting. We hypothesize that KPC-KP load may behave as a surrogate marker for the severity of the patient's clinical condition.