The Changing Epidemiology of Carbapenemase-Producing Enterobacterales

Risk Factors and Outcomes of Patients Colonized with KPC and NDM Carbapenemase-Producing Enterobacterales

Carbapenemase-producing enterobacterales (CPE) poses an increasing threat in hospitals worldwide. Recently, the prevalence of different carbapenemases conferring carbapenem resistance in enterobacterales changed in our country, including an increase in New Delhi Metallo-beta-lactamase (NDM)-CPE. We conducted a comparative historical study of adult patients colonized with Klebsiella pneumoniae carbapenemase (KPC)-CPE (July 2016 to June 2018, a historical cohort) vs. NDM-CPE (July 2016 to January 2023). We identified patients retrospectively through the microbiology laboratory and reviewed their files, extracting demographics, underlying diseases, Charlson Comorbidity Index (CCI) scores, treatments, and outcomes. This study included 228 consecutive patients from whom a CPE rectal swab screening was obtained: 136 NDM-CPE positive and 92 KPC-CPE positive. NDM-CPE-colonized patients had a shorter hospitalization length and a significantly lower 30-day post-discharge mortality rate (p = 0.002) than KPC-CPE-colonized patients. Based on multivariate regression, independent risk factors predicting CPE-NDM colonization included admission from home and CCI < 4 (p < 0.001, p = 0.037, respectively). The increase in NDM-CPE prevalence necessitates a modified CPE screening strategy upon hospital admission tailored to the changing local CPE epidemiology. In our region, the screening of younger patients residing at home with fewer comorbidities should be considered, regardless of a prior community healthcare contact or hospital admission.

Risk factors for acquisition of carbapenemase-producing versus non-carbapenemase-producing enterobacterales: a case-control study

OBJECTIVES

We aimed to assess the association between carbapenem-resistant Enterobacterales (CRE) colonization pressure and carbapenem exposure and acquisition of carbapenemase-producing Enterobacterales (CPE) and non-carbapenemase-producing carbapenem-resistant Enterobacterales (non-CP-CRE).

METHODS

We conducted a parallel 1:2 matched case-control study at Rambam Health Care Campus, Israel, from January 2014 to June 2017. The cases included all adults who acquired CPE or non-CP-CRE in hospital. The controls were hospitalized patients who were negative for CRE on screening and matched by age, hospitalization division and the number of hospitalization days 90 days prior to CRE screening. The exposures of interest were high CRE colonization pressure, defined as a higher-than-median proportion of CRE carriers in the concurrent patient's department before acquisition, and carbapenem exposure, assessed as days of treatment. Conditional logistic regression was used for analyses of CPE and non-CP-CRE.

RESULTS

In total, 1058 patients were included: 278 CPE and 75 non-CP-CRE cases, matched to 556 and 149 controls, respectively. High CRE colonization pressure was associated with CPE acquisition (adjusted odds ratio [aOR], 2.6; 95% CI, 1.69-4.02); however, the duration of carbapenem treatment was not (aOR, 1.004; 95% CI, 0.98-1.03; 1-day increment). The duration of carbapenem treatment was significantly associated with non-CP-CRE acquisition (aOR per day, 1.07; 95% CI, 1.03-1.11). A source patient was identified significantly more frequently in epidemiological acquisition investigations of CPE than in those of non-CP-CRE (107/240, 44.6% vs. 18/64, 28.1%, respectively; p 0.017).

CONCLUSIONS

CPE acquisition was associated with horizontal transmission, whereas non-CP-CRE was associated with carbapenem exposure. Differences in the drivers of acquisition mandate tailored infection prevention efforts.

Microbial epidemiology and clinical risk factors of carbapenemase-producing Enterobacterales amongst Irish patients from first detection in 2009 until 2020

Background

Carbapenemase producing Enterobacterales (CPE) are major public health threats.

Aim

To review microbial epidemiology of CPE, as well as clinical risk factors and infections, amongst CPE positive patients over 12 years in an Irish tertiary hospital.

Methods

Retrospective observational study of data extracted from a laboratory CPE database, electronic healthcare records and manual review of patient charts. Common risk factors, treatment regimens for all CPE related infections, and clinical outcomes were ascertained.

Findings

Among CPE strains isolated from 460 patients, Klebsiella pneumoniae carbapenemase (KPC) was the carbapenemase most frequently detected, accounting for 87.4% (459) of all CPE enzymes. Citrobacter species 177 (33.7%) were the most common species harbouring this enzyme. 428 CPE positive patients (93%) were identified in the acute hospital setting; the most common risk factor for CPE acquisition was history of hospitalisation, observed in 305 (66%) cases. Thirty patients (6.5%) had confirmed infections post-acquisition, of which four were bloodstream infections. There were 19 subsequent episodes of non CPE-related bacteraemia in this cohort. All causal mortality at 30 days was 41 patients (8.9%). However, clinical review determined that CPE was an indirect associative factor in 8 patient deaths.

Conclusions

In this tertiary hospital setting, microbial epidemiology is changing; with both OXA-48 enzymes and KPC-producing Citrobacter species becoming more prevalent. Whilst the burden of CPE related infections, especially bacteraemia, was low over the study period, it remains critical that basic infection prevention and control practices are adhered to lest the observed changes in epidemiology result in an increase in clinical manifestations.