The impact of non-antimicrobial drug agents on the acquisition of ESBL-producing Enterobacterales in non-critical care wards in a German university hospital: an exploratory, matched case-control study

Risk factors for Pseudomonas aeruginosa VIM colonization or infection in the ICU: Case-control study

BACKGROUND

Carbapenem-resistant strains of Pseudomonas aeruginosa (CRPA) have become a major health care concern in many countries, against which anti-infective strategies are limited and which require adequate infection control interventions. Knowing the different modes of transmission of CRPA in intensive care units (ICUs) would be helpful to adapt the means of prevention.

METHODS

The aim of this retrospective case-control study was conducted between January 1, 2017 and February 28, 2022 to identify the risk factors for the acquisition of CRPA in ICUs.

RESULTS

During the study period, 147 patients were included (49 cases and 98 controls). Among the 49 patients, 31 (63%) acquired CRPA in clusters and 18 (37%) sporadically. A univariate analysis showed that 4 variables were associated with CRPA acquisition, including (1) prior antibiotic prescriptions, (2) admission to rooms 203 and 207, (3) severity of illness at admission, and (4) use of mechanical ventilation. Multivariate analysis identified 3 factors of CRPA acquisition, including admission to room 203 (odds ratio [OR] = 29.5 [3.52-247.09]), previous antibiotic therapy (OR = 3.44 [1.02-11.76]), and severity of condition at admission (OR = 1.02 [1-1.04]).

CONCLUSIONS

Our study suggests the role of a contaminated environment in the acquisition of CRPA in the ICU, along with antibiotic use.

Etiology of nosocomial infections in intensive care patients in German hospitals: An analysis of trends between 2008 and 2022

PURPOSE

Data from the intensive care component of the German hospital infection surveillance system (KISS) was used to investigate the epidemiology of pathogens responsible for the most frequent device-associated infections and their development over time.

METHOD

The 10 most common pathogens were identified for ventilator-associated lower respiratory tract infections (VALRTI), catheter associated urinary tract infections (CAUTI), and central venous catheter associated bloodstream infections (CVC-BSI). The development over time was analyzed based on three five-year time periods: 2008-2012, 2013-2017, 2018-2022.

RESULTS

Data from 1425 ICUs were included together with 121,762 device-associated infections with 138,299 isolated pathogens. A remarkable and significant increase in the frequency of Klebsiella spp. was found for VALRTI, that was almost twice as high during 2018-2022 compared to 2008-2012. For CAUTI, there was a significant increase of all Enterobacterales with the most prominent increase in Klebsiella spp. With regard to CVC-BSI, the situation for coagulase-negative staphylococci and E. coli was relatively stable; while there was a significant increase in Enterococcus spp. and Klebsiella spp. and a decrease in S. aureus.

CONCLUSION

Knowledge about the current frequency of pathogens responsible for nosocomial infections in intensive care units is important for guiding empirical antimicrobial therapy. Data from national nosocomial infection surveillance systems can provide relevant information about the development of pathogens.

Quantification of time delay between screening and subsequent initiation of contact isolation for carriers of extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales: A post hoc subgroup analysis of the R-GNOSIS WP5 Trial

OBJECTIVES

The aim of this study was to quantify the time delay between screening and initiation of contact isolation for carriers of extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales (ESBL-E).

METHODS

This study was a secondary analysis of contact isolation periods in a cluster-randomized controlled trial that compared 2 strategies to control ESBL-E (trial no. ISRCTN57648070). Patients admitted to 20 non-ICU wards in Germany, the Netherlands, Spain, and Switzerland were screened for ESBL-E carriage on admission, weekly thereafter, and on discharge. Data collection included the day of sampling, the day the wards were notified of the result, and subsequent ESBL-E isolation days.

RESULTS

Between January 2014 and August 2016, 19,122 patients, with a length of stay ≥2 days were included. At least 1 culture was collected for 16,091 patients (84%), with a median duration between the admission day and the day of first sample collection of 2 days (interquartile range [IQR], 1-3). Moreover, 854 (41%) of all 2,078 ESBL-E carriers remained without isolation during their hospital stay. In total, 6,040 ESBL-E days (32% of all ESBL-E days) accrued for patients who were not isolated. Of 2,078 ESBL-E-carriers, 1,478 ESBL-E carriers (71%) had no previous history of ESBL-E carriage. Also, 697 (34%) were placed in contact isolation with a delay of 4 days (IQR, 2-5), accounting for 2,723 nonisolation days (15% of ESBL-E days).

CONCLUSIONS

Even with extensive surveillance screening, almost one-third of all ESBL-E days were nonisolation days. Limitations in routine culture-based ESBL-E detection impeded timely and exhaustive implementation of targeted contact isolation.

Association of Proton Pump Inhibitor Use With Risk of Acquiring Drug-Resistant Enterobacterales

IMPORTANCE

Proton-pump inhibitors (PPIs) have been associated with the risk of colonization with drug-resistant bacteria; however, possible confounding by lifestyle-associated factors and disease severity casts doubt on this association, and whether the risk is dose dependent is not known.

OBJECTIVES

To assess the association between PPI use and the risk of acquiring drug-resistant Enterobacterales and to examine interactions with possible microbiome-altering agents.

DESIGN, SETTING, AND PARTICIPANTS

This nested case-control study involved 2239 hospitalized adult (aged ≥18 years) patients identified from the microbiology laboratory database of Amsterdam University Medical Centers between December 31, 2018, and January 6, 2021. Patients in the case group had newly detected extended-spectrum β-lactamase (ESBL)- or carbapenemase-producing Enterobacterales (identified by clinical specimens). Risk-set sampling was used to assign patients with negative results for ESBL- and carbapenemase-producing Enterobacterales to the control group, who were then matched on a 5:1 ratio with patients in the case group by age and culture date. A second validation case-control study included matched pairs (1:1 ratio; 94 in each group) of patients who were prospectively enrolled.

EXPOSURES

Proton pump inhibitor use and clinical data at 30 days (primary exposure) and 90 days (secondary exposure) before the date of culture.

MAIN OUTCOMES AND MEASURES

Adjusted incidence rate ratios (aIRRs) of ESBL- or carbapenemase-producing Enterobacterales acquisition by PPI dose and time risk windows (30 days for the primary outcome and 90 days for the secondary outcome) were estimated using conditional logistic regression models.

RESULTS

Among 2239 hospitalized patients (51.1% male; mean [SD] age, 60.9 [16.7] years), 374 were in the case group (51.6% male; mean [SD] age, 61.1 [16.5] years) and 1865 were in the matched control group (51.0% male; mean [SD] age, 60.9 [16.7] years). The aIRR for PPI use overall was 1.48 (95% CI, 1.15-1.91) at 30 days. Sensitivity analyses and the analysis of the pair-matched study with prospectively enrolled patients (aIRR, 2.96, 95% CI, 1.14-7.74) yielded similar results; findings were consistent in subgroups and corroborated by a negative-control exposure analysis. No association with microbiome-disturbing agents was found; laxatives and antibiotics were independently associated with a more than 2-fold increase in the risk of acquisition (antibiotics: aIRR, 2.78 [95% CI, 2.14-3.59]; laxatives: aIRR, 2.26 [95% CI. 1.73-2.94]).

CONCLUSIONS AND RELEVANCE

In this study, after careful control for confounding and sensitivity analyses, PPI use was associated with increases in the risk of acquiring ESBL- or carbapenemase-producing Enterobacterales among adult hospitalized patients. These findings emphasize the need for judicious use of PPIs.

Transfer of Extended Spectrum Cephalosporin Resistant Enterobacteriaceae Among Patients on an HSCT Unit and the Value of Surveillance and Contact Isolation

The mechanism(s) of acquisition of extended-spectrum cephalosporin-resistant Enterobacteriaceae (ESCRE) on inpatient hospital units dedicated to hematopoietic stem cell transplantation (HSCT) is unclear. The objectives of this study were to determine whether ESCRE organisms are transmitted among patients housed on a HSCT unit, clarify the mechanisms involved, and determine whether routine surveillance for ESCRE carriage and contact isolation for ESCRE carriers is beneficial. The study was conducted on a 30-bed inpatient unit dedicated to the care of patients with hematologic malignancies and HSCT recipients. To investigate whether ESCRE organisms may be transmitted vertically to subsequent room occupants, presumably through contamination of room surfaces, we (1) cultured 6 high touch areas in 10 rooms before and 9 rooms after terminal cleaning that had been occupied by patients with ESCRE carriage, (2) determined the in vitro survivals of our most common clinical ESCRE species, and (3) followed the subsequent room occupants of 54 consecutive ESCRE colonized patients for the development of inpatient acquired ESCRE carriage. To investigate whether ESCRE organisms are transmitted horizontally among inpatients we (1) sequenced 60 available ESCRE Escherichia coli isolates obtained from unit inpatients and searched for identities using complete-genome multisequence locus typing (cgMLST) and (2) retrospectively tabulated the cumulative rates of acquired ESCRE carriage in 356 patients admitted for a first HSCT before (200 patients) or after (156 patients) institution of universal ESCRE stool surveillance and contact isolation for carriers. No ESCRE organisms were cultured from patient rooms before or after terminal cleaning. In vitro, few, if any, ESCRE organisms survived longer than 2 hours. Nine of the subsequent occupants of a room in which a patient with ESCRE carriage had resided were detected with ESCRE carriage, only 2 of whom carried the same species as that of the prior occupant. DNA sequencing and cgMLST determination of the 60 E. coli isolates showed 53 cgMLST strains. Seven of the 53 strains were shared by 2 patients. After institution of universal ESCRE surveillance/isolation there was a significant decline in acquired ESCRE carriage among HSCT recipients. We conclude that vertical transmission of ESCRE organisms through room contamination appears to be uncommon on modern HSCT units. Conversely, our results are consistent with the horizontal spread of ESCRE organisms, probably mediated by intermediate vectors such as personnel or shared equipment. Further studies are needed to better define the magnitude of and risk factors for ESCRE horizontal transfers and the benefits of ESCRE surveillance/isolation.