Carbapenemase-producing Enterobacterales: changing epidemiology in a highly endemic Italian area

High Frequency of Detection of NDM-Producing Enterobacterales Among Companion Animals Hospitalized in an Italian Veterinary Teaching Hospital

Carbapenems are considered one of the most important last-resort classes of antibiotics, and the spread of carbapenem-resistant Enterobacterales (CRE) is a serious concern worldwide. From a One Health point of view, reports on CRE in companion animals are increasing, requiring attention regarding their role in maintenance and direct transmission to humans. The aim of this study was to assess the frequency of detection at admission and the in-hospital acquisition of CRE from perirectal swabs in dogs and cats hospitalized in an Italian Veterinary Teaching Hospital (VTH). Of the 150 patients sampled, 11.3% (n = 17) were CRE carriers at admission, 25.6% (n = 34) acquired CRE in their commensal microbiota during their hospital stay, and 2% (n = 3) developed an infection caused by CRE. Genotypical analysis showed that in 100% (78/78) of the CRE isolates (44 Escherichia coli, 33 Klebsiella pneumoniae, and 1 Klebsiella aerogenes) carbapenem resistance was conferred by the carbapenemase gene blaNDM, suggesting an endemic presence of such gene within the hospital. Co-occurrent β-lactamase-encoding genes were found in most of the isolates. Risk factors associated with CRE acquisition were length of hospitalization (p=0.0002) and treatment with piperacillin-tazobactam (PTZ; p=0.0380), indicating potential cross-selection of CRE. These results reinforce the suspicion that companion animals could silently contribute to the maintenance and dissemination of CRE in the local community, posing a threat to global health.

Enterobacterales carrying chromosomal AmpC β-lactamases in Europe (EuESCPM): Epidemiology and antimicrobial resistance burden from a cohort of 27 hospitals, 2020-2022

INTRODUCTION

The ESCPM group (Enterobacter species including Klebsiella aerogenes - formerly Enterobacter aerogenes, Serratia species, Citrobacter freundii complex, Providencia species and Morganella morganii) has not yet been incorporated into systematic surveillance programs.

METHODS

We conducted a multicentre retrospective observational study analysing all ESCPM strains isolated from blood cultures in 27 European hospitals over a 3-year period (2020-2022). Diagnostic approach, epidemiology, and antimicrobial susceptibility were investigated.

RESULTS

Our study comprised 6,774 ESCPM isolates. MALDI-TOF coupled to mass spectrometry was the predominant technique for bacterial identification. Susceptibility to new β-lactam/β-lactamase inhibitor combinations and confirmation of AmpC overproduction were routinely tested in 33.3% and 29.6% of the centres, respectively. The most prevalent species were E. cloacae complex (44.8%) and S. marcescens (22.7%). Overall, third-generation cephalosporins (3GC), combined third- and fourth-generation cephalosporins (3GC + 4GC) and carbapenems resistance phenotypes were observed in 15.7%, 4.6%, and 9.5% of the isolates, respectively. AmpC overproduction was the most prevalent resistance mechanism detected (15.8%). Among carbapenemase-producers, carbapenemase type was provided in 44.4% of the isolates, VIM- (22.9%) and OXA-48-enzyme (16%) being the most frequently detected. E. cloacae complex, K. aerogenes and Providencia species exhibited the most notable cumulative antimicrobial resistance profiles, with the former displaying 3GC, combined 3GC + 4GC and carbapenems resistance phenotypes in 15.2%, 7.4%, and 12.8% of the isolates, respectively. K. aerogenes showed the highest rate of both 3GC resistant phenotype (29.8%) and AmpC overproduction (32.1%), while Providencia species those of both carbapenems resistance phenotype (42.7%) and carbapenemase production (29.4%). ESCPM isolates exhibiting both 3GC and combined 3GC + 4GC resistance phenotypes displayed high susceptibility to ceftazidime/avibactam (98.2% and 95.7%, respectively) and colistin (90.3% and 90.7%, respectively). Colistin emerged as the most active drug against ESCPM species (except those intrinsically resistant) displaying both carbapenems resistance phenotype (85.8%) and carbapenemase production (97.8%).

CONCLUSIONS

This study presented a current analysis of ESCPM species epidemiology in Europe, providing insights to inform current antibiotic treatments and guide strategies for antimicrobial stewardship and diagnostics.

Multicenter study on the prevalence of colonization due to carbapenem-resistant Enterobacterales strains before and during the first year of COVID-19, Italy 2018-2020

Background

Among multidrug-resistant (MDR) bacteria able to threaten human health, carbapenem-resistant Enterobacterales (CRE) have become a major public health threat globally. National and international guidelines point out the importance of active routine surveillance policies to prevent CRE transmission. Therefore, defining lines of intervention and strategies capable of containing and controlling the spread of CRE is considered determinant. CRE screening is one of the main actions to curb transmission and control outbreaks, outlining the presence and also the prevalence and types of carbapenemase enzymes circulating locally.

Objective

The purpose of this study was to outline the epidemiology of CRE colonization in Italy, detecting CRE-colonized patients at admission and during hospitalization, before and during the first year of COVID-19.

Materials and methods

A total of 11,063 patients admitted to seven different hospitals (Bologna, Catania, Florence, Genoa, Naples, Palermo, and Turin) in Intensive Care Units (ICU) and other wards (non-ICU) located in the North, Center, and South of Italy were enrolled and screened for CRE carriage at admission (T0) and during the first 3 weeks of hospitalization (T1-T3). The study spanned two periods, before (September 2018-Septemeber 2019, I observational period) and during the COVID-19 pandemic (October 2019-September 2020, II observational period).

Results

Overall, the prevalence of CRE-colonized patients at admission in ICU or in other ward, ranged from 3.9 to 11.5%, while a percentage from 5.1 to 15.5% of patients acquired CRE during hospital stay. There were large differences between the I and II period of study according to the different geographical areas and enrolling centers. Overall, comparison of prevalence of CRE-positive patients showed a significant increased trend between I and II observational periods both in ICU and non-ICU wards, mostly in the Southern participating centers. KPC-producing Klebsiella pneumoniae was the most frequent CRE species-carbapenemase combination reported in this study. In particular, the presence of KPC-producing K. pneumoniae was reported in period I during hospitalization in all the CRE-positive patients enrolled in ICU in Turin (North Italy), while in period II at admission in all the CRE-positive patients enrolled in ICU in Catania and in 58.3% of non-ICU CRE-positive patients in Naples (both centers in South Italy).

Conclusion

The prevalence of CRE in Italy highly increased during the COVID-19 pandemic, mostly in the Southern hospital centers. KPC-producing K. pneumoniae was the most frequent colonizing CRE species reported. The results of our study confirmed the crucial value of active surveillance as well as the importance of multicenter studies representing diverse geographical areas even in endemic countries. Differences in CRE colonization prevalence among centers suggest the need for diversified and center-specific interventions as well as for strengthening efforts in infection prevention and control practices and policies.

Multicentre Evaluation of the EUCAST Rapid Antimicrobial Susceptibility Testing (RAST) Extending Analysis to 16-20 Hours Reading Time

The aim of the study was to evaluate the EUCAST RAST method by extending analysis to 16−20 h reading time and performance with new β-lactam/β-lactamase inhibitor combinations. A total of 676 positive blood cultures (BCs) were enrolled. Results at 4 h, 6 h, 8 h and 16−20 h were interpreted according to bacterial species using EUCAST RAST breakpoints (version 5.1). For species for which no breakpoints were available, tentative breakpoints were used. Categorical agreement with the Microscan microdilution system was analysed. Among the 676 BCs enrolled, 641 were monomicrobial and were included in the analysis. Categorical agreement ranged from 98.9% at 4 h to 99.4% at 16−20 h. The rates of very major errors were 3.3%, 3.7% and 3.4% at 4 h, 6 h and 8 h, respectively, and decreased to 1% at 16−20 h (p < 0.001). The number of major errors was low for each reading time (0.2% and 0.4% at 4 h and 6 h, respectively, and 0.3% at both 8 h and 16−20 h). The proportions of results in the area of technical uncertainty were 9.9%, 5.9%, 5% and 5.2% for readings at 4 h, 6 h, 8 h and 16−20 h, respectively. Tentative breakpoints proposed for Enterobacterales other than E.coli/K.pneumoniae and coagulase-negative staphylococci showed overall performances comparable to those observed for E. coli/K. pneumoniae and S. aureus. In conclusion, EUCAST RAST has been shown to be reliable to determine microbial susceptibility to main antimicrobials, including ceftazidime/avibactam and ceftolozane/tazobactam. A poorer performance was observed for certain species/antimicrobial agent combinations. The better performance observed at 16−20 h compared to the early readings may confer to the method greater potential for antimicrobial de-escalation interventions.

Complete Genome Sequence of a Multidrug-Resistant Klebsiella pneumoniae Strain Carrying blaOXA181 and blaKPC-125 Carbapenemase

Carbapenemase-producing Enterobacterales (CPEs) strains represent a serious threat to public health. The rapid diffusion of CPEs is of particular concern due to the limited effective treatments available against these multidrug resistant microorganisms. In this study, we characterized the complete genome sequence of Klebsiella pneumoniae strain BO714 coproducing KPC and OXA-181 carbapenemase conferring resistance to all β-lactam/β-lactamase inhibitor combinations (βL-βLICs) and siderophore cephalosporin cefiderocol (CFD). The genome of BO714 has a length of 5,876,068 bp with an average G + C content of 56.96% and a total of 5,878 open reading frames. The KPC-Kp strain BO714 was classified as ST512 and contained a circular chromosome of 5,348,787 bp and three different plasmids, respectively, of 363,560, 112,243, and 51,478 bp. Resistome analysis showed that BO714 harbored different β-lactamase genes including bla_CMY-16, bla_OXA-10, bla_TEM-1, bla_SHV-11, bla_OXA181, and a novel bla_KPC-3 variant named bla_KPC-125. KPC-125 differed to KPC-3 by Asp to Ala at position 179 within the Ω-loop region. The genomic characterization of a K. pneumoniae cross-resistant to novel βL-βLICs and CFD improves knowledge regarding the emergence of novel traits of multidrug resistance in CPEs.

Characteristics and outcomes of carbapenemase harbouring carbapenem-resistant Klebsiella spp. bloodstream infections: a multicentre prospective cohort study in an OXA-48 endemic setting

A prospective, multicentre observational cohort study of carbapenem-resistant Klebsiella spp. (CRK) bloodstream infections was conducted in Turkey from June 2018 to June 2019. One hundred eighty-seven patients were recruited. Single OXA-48-like carbapenemases predominated (75%), followed by OXA-48-like/NDM coproducers (16%). OXA-232 constituted 31% of all OXA-48-like carbapenemases and was mainly carried on ST2096. Thirty-day mortality was 44% overall and 51% for ST2096. In the multivariate cox regression analysis, SOFA score and immunosuppression were significant predictors of 30-day mortality and ST2096 had a non-significant effect. All OXA-48-like producers remained susceptible to ceftazidime-avibactam.

Successful Treatment of Bacteremia and Ventilator-Associated Pneumonia Caused by KPC/OXA-48-like Klebsiella pneumoniae Co-Producer with a Continuous Infusion of High-Dose Meropenem Plus Fosfomycin Guided by Real-Time Therapeutic Drug Monitoring

Bacteremia and ventilator-associated pneumonia due to a pan-resistant Klebsiella pneumoniae strain co-producing KPC and OXA-48 carbapenemases was successfully treated in a COVID-19 critically ill patient with a combination therapy of a high-dose continuous infusion of meropenem (up to 3 g every 6 h, daily) plus fosfomycin (up to 24 g/daily) that was guided by real-time therapeutic drug monitoring. Clinical pharmacological advice was helpful in maximizing, over time, the pharmacodynamic target attainment of both antibiotics.