Characterisation of OXA-244, a chromosomally-encoded OXA-48-like β-lactamase from Escherichia coli

Plasmid conjugation drives within-patient plasmid diversity

Plasmids are well-known vehicles of antimicrobial resistance (AMR) gene dissemination. Through conjugation, plasmid-encoded AMR genes are spread among neighbouring bacteria, irrespective of their strain or even their species. This process is very concerning from a public health perspective, as plasmid-borne AMR gene outbreaks are often not confined to single species or strains and are therefore more difficult to fully uncover. At the moment, the impact of plasmid conjugation on within-patient plasmid diversity is not well understood. In this work, we will tackle the role of conjugation on within-patient plasmid diversity using a dataset of carbapenemase-producing Enterobacterales. The dataset of 256 sequences originates from bacterial isolates cultured from 115 English patients over 30 months. Each patient has more than one sequence, with at least one sequence carrying an OXA-48 gene, a well-known plasmid-borne carbapenemase-encoding gene. If more than one sequence carries the OXA-48 gene, they are carried in different bacterial hosts. Using a hybrid de novo-on-reference assembly pipeline, we were able to reconstruct the full OXA-48 plasmid from short read sequencing data for 232 of the 256 sequences. Of the 115 patients, 83 (72%) patients had an identical OXA-48 plasmid in two or more sequences. Only two patients carried very different (>200 SNPs) alleles of the OXA-48 plasmid, probably from separate acquisitions. Our study shows that when more than one bacterial host carrying an OXA-48 plasmid is found in a patient, it is most likely that the same plasmid has been shared via conjugation. The event of separate acquisition of different plasmids in different bacterial hosts is highly unlikely in our dataset.

Plasmid genomic epidemiology of carbapenem-hydrolysing class D β-lactamase (CDHL)-producing Enterobacterales in Canada, 2010-2021

Carbapenems are last-resort antibiotics for treatment of infections caused by multidrug-resistant Enterobacterales, but carbapenem resistance is a rising global threat due to the acquisition of carbapenemase genes. Oxacillinase-48 (bla OXA-48)-type carbapenemases are increasing in abundance in Canada and elsewhere; these genes are frequently found on mobile genetic elements and are associated with specific transposons. This means that alongside clonal dissemination, bla OXA-48-type genes can spread through plasmid-mediated horizontal gene transfer. We applied whole genome sequencing to characterize 249 bla OXA-48-type-producing Enterobacterales isolates collected by the Canadian Nosocomial Infection Surveillance Program from 2010 to 2021. Using a combination of short- and long-read sequencing, we obtained 70 complete and circular bla OXA-48-type-encoding plasmids. Using MOB-suite, four major plasmids clustered were identified, and we further estimated a plasmid cluster for 91.9 % (147/160) of incomplete bla OXA-48-type-encoding contigs. We identified different patterns of carbapenemase mobilization across Canada, including horizontal transmission of bla OXA-181/IncX3 plasmids (75/249, 30.1 %) and bla OXA-48/IncL/M plasmids (47/249, 18.9 %), and both horizontal transmission and clonal transmission of bla OXA-232 for Klebsiella pneumoniae ST231 on ColE2-type/ColKP3 plasmids (25/249, 10.0 %). Our findings highlight the diversity of OXA-48-type plasmids and indicate that multiple plasmid clusters and clonal transmission have contributed to bla OXA-48-type spread and persistence in Canada.

Large hospital outbreak caused by OXA-244-producing Escherichia coli sequence type 38, Poland, 2023

In February 2023, Escherichia coli sequence type (ST) 38 producing oxacillinase 244 (OXA-244-Ec ST38) was detected from three patients in a hospital in western Poland. Overall, OXA-244-Ec ST38 was detected from 38 colonised patients in 13 wards between February and June 2023. The outbreak was investigated on site by an infection control team, and the bacterial isolates were characterised microbiologically and by whole genome sequencing. We could not identify the primary source of the outbreak or reconstruct the transmission sequence. In some of the 13 affected wards or their groups linked by the patients' movement, local outbreaks occurred. The tested outbreak isolates were resistant to β-lactams (penicillins, cephalosporins, aztreonam and ertapenem) and to trimethoprim-sulfamethoxazole. Consistently, apart from bla OXA-244, all isolates contained also the bla CMY-2 and bla CTX-M-14 genes, coding for an AmpC-like cephalosporinase and extended-spectrum β-lactamase, respectively, and genes conferring resistance to trimethoprim-sulfamethoxazole, sul2 and dfrA1. Genomes of the isolates formed a tight cluster, not of the major recent European Cluster A but of the older Cluster B, with related isolates identified in Germany. This outbreak clearly demonstrates that OXA-244-Ec ST38 has a potential to cause hospital outbreaks which are difficult to detect, investigate and control.

Prolonged carriage of OXA-244-carbapenemase-producing Escherichia coli complicates epidemiological investigations

The rapid increase of OXA-244-producing Escherichia coli, predominantly driven by genetically clustered isolates of sequence type (ST)38, has been observed in at least nine European countries, including Germany. However, the reasons for the spread of OXA-244-producing E. coli remain unclear. Here, we aim to evaluate the possibility of prolonged carriage. We identified a total of six different patients with repeated detection of OXA-244-producing E. coli isolates, which were subjected to both short and long-read whole-genome sequencing (WGS). Besides allelic differences using core genome multilocus sequence typing (cgMLST) analyses, we obtained numbers of single-nucleotide polymorphisms (SNPs) to calculate individual base-pair substitution (BPS) rates. To assess possible re-exposure and risk factors for prolonged carriage, case interviews were conducted. The time between detections ranged from eleven months to more than three years. Initial isolates originated in three+ out of six cases from clinical samples, whereas remaining samples were from screening, mostly in the inpatient setting. As expected, cgMLST analyses showed low numbers of allelic differences between isolates of each case ranging from 1 to 4, whereas numbers of SNPs were between 2 and 99 (mean = 36), thus clearly highlighting the discrepancy between these different bacterial typing approaches. For five out of six cases, observed BPS rates suggest that patients can be colonized with OXA-244-producing E. coli, including ST38 cluster isolates, for extensively long times. Thus, we may have previously missed the epidemiological link between cases because exposure to OXA-244-producing E. coli could have occurred in a time frame, which has not been evaluated in previous investigations. Our results may help to guide future epidemiological investigations as well as to support the interpretation of genetic diversity of OXA-244-producing E. coli, particularly among ST38 cluster isolates.

Clinical isolates of ST131 blaOXA-244-positive Escherichia coli, Italy, December 2022 to July 2023

The dissemination of carbapenemase-producing Escherichia coli, although still at low level, should be continuously monitored. OXA-244 is emerging in Europe, mainly in E. coli. In Italy, this carbapenemase was reported from an environmental river sample in 2019. We report clinical isolates of OXA-244-producing ST131 E. coli in four patients admitted to an acute care hospital in Pavia, Italy. The association of this difficult-to-detect determinant with a globally circulating high-risk clone, ST131 E. coli, is of clinical relevance.

The emergence of carbapenemase-producing Enterobacterales in hospitals: a major challenge for a debilitated healthcare system in Lebanon

Background

Carbapenem- and extended-spectrum cephalosporin-resistant Enterobacterales (CR-E and ESCR-E, respectively) are increasingly isolated worldwide. Information about these bacteria is sporadic in Lebanon and generally relies on conventional diagnostic methods, which is detrimental for a country that is struggling with an unprecedented economic crisis and a collapsing public health system. Here, CR-E isolates from different Lebanese hospitals were characterized.

Materials and methods

Non-duplicate clinical ESCR-E or CR-E isolates (N = 188) were collected from three hospitals from June 2019 to December 2020. Isolates were identified by MALDI-TOF, and their antibiotic susceptibility by Kirby-Bauer disk diffusion assay. CR-E isolates (n = 33/188) were further analyzed using Illumina-based WGS to identify resistome, MLST, and plasmid types. Additionally, the genetic relatedness of the CR-E isolates was evaluated using an Infrared Biotyper system and compared to WGS.

Results

Using the Kirby-Bauer disk diffusion assay, only 90 isolates out of the 188 isolates that were collected based on their initial routine susceptibility profile by the three participating hospitals could be confirmed as ESCR-E or CR-E isolates and were included in this study. This collection comprised E. coli (n = 70; 77.8%), K. pneumoniae (n = 13; 14.4%), Enterobacter spp. (n = 6; 6.7%), and Proteus mirabilis (n = 1; 1.1%). While 57 were only ESBL producers the remaining 33 isolates (i.e., 26 E. coli, five K. pneumoniae, one E. cloacae, and one Enterobacter hormaechei) were resistant to at least one carbapenem, of which 20 were also ESBL-producers. Among the 33 CR-E, five different carbapenemase determinants were identified: blaNDM-5 (14/33), blaOXA-244 (10/33), blaOXA-48 (5/33), blaNDM-1 (3/33), and blaOXA-181 (1/33) genes. Notably, 20 CR-E isolates were also ESBL-producers. The analysis of the genetic relatedness revealed a substantial genetic diversity among CR-E isolates, suggesting evolution and transmission from various sources.

Conclusion

This study highlighted the emergence and broad dissemination of blaNDM-5 and blaOXA-244 genes in Lebanese clinical settings. The weak AMR awareness in the Lebanese community and the ongoing economic and healthcare challenges have spurred self-medication practices. Our findings highlight an urgent need for transformative approaches to combat antimicrobial resistance in both community and hospital settings.

Bloodstream infections due to Carbapenem-Resistant Enterobacteriaceae in hematological patients: assessment of risk factors for mortality and treatment options

PURPOSE

Bloodstream infection (BSI) caused by Carbapenem-Resistant Enterobacteriaceae (CRE) are associated with poor outcomes in hematological patients. The aim of this study was to identify risk factors for mortality and evaluate the value of epidemiological feature of carbapenemases in guiding antimicrobial treatment options.

METHODS

Hematological patients with monomicrobial CRE BSI between January 2012 and April 2021 were included. The primary outcome was all-cause mortality 30 days after BSI onset.

RESULTS

A total of 94 patients were documented in the study period. Escherichia coli was the most common Enterobacteriaceae, followed by Klebsiella pneumoniae. 66 CRE strains were tested for carbapenemase genes, and 81.8% (54/66) were positive, including NDM (36/54), KPC (16/54), IMP (1/54). Besides, one E. coli isolate was found to express both NDM and OXA-48-like genes. Overall, 28 patients received an antimicrobial treatment containing ceftazidime-avibactam (CAZ-AVI), of which 21 cases were combined with aztreonam. The remaining 66 patients were treated with other active antibiotics (OAAs). The 30-day mortality rate was 28.7% (27/94) for all patients, and was only 7.1% ((2/28) for patients treated with CAZ-AVI. In multivariate analysis, the presence of septic shock at BSI onset (OR 10.526, 95% CI 1.376-76.923) and pulmonary infection (OR 6.289, 95% CI 1.351-29.412) were independently risk factors for 30-day mortality. Comparing different antimicrobial regimens, CAZ-AVI showed a significant survive benefit than OAAs (OR 0.068, 95% CI 0.007-0.651).

CONCLUSION

CAZ-AVI-containing regimen is superior to OAAs for CRE BSI. As the predominance of blaNDM in our center, we recommend the combination with aztreonam when choose CAZ-AVI.

Molecular analysis of OXA-48-producing Escherichia coli in Switzerland from 2019 to 2020

OXA-48-type ß-lactamases are the most prevalent carbapenemase-type in Enterobacterales in Switzerland, predominantly found in Escherichia coli and Klebsiella pneumoniae. Bacteria-producing OXA-48-type enzymes are endemic in some parts of the world, including Europe and North Africa, and are a frequent cause of nosocomial infections. Despite the emergence of numerous OXA-48-type variants, the original variant, OXA-48, remains the most prevalent in E. coli. This study describes the epidemiology of OXA-48-producing E. coli isolates submitted to the Swiss National Reference Center for Emerging Antibiotic Resistance (NARA) between January 2019 and December 2020.

Empiric Treatment in HAP/VAP: “Don’t You Want to Take a Leap of Faith?”

Ventilator-associated pneumonia is a frequent cause of ICU-acquired infections. These infections are associated with high morbidity and mortality. The increase in antibiotic resistance, particularly among Gram-negative bacilli, makes the choice of empiric antibiotic therapy complex for physicians. Multidrug-resistant organisms (MDROs) related infections are associated with a high risk of initial therapeutic inadequacy. It is, therefore, necessary to quickly identify the bacterial species involved and their susceptibility to antibiotics. New diagnostic tools have recently been commercialized to assist in the management of these infections. Moreover, the recent enrichment of the therapeutic arsenal effective on Gram-negative bacilli raises the question of their place in the therapeutic management of these infections. Most national and international guidelines recommend limiting their use to microbiologically documented infections. However, many clinical situations and, in particular, the knowledge of digestive or respiratory carriage by MDROs should lead to the discussion of the use of these new molecules, especially the new combinations with beta-lactamase inhibitors in empirical therapy. In this review, we present the current epidemiological data, particularly in terms of MDRO, as well as the clinical and microbiological elements that may be taken into account in the discussion of empirical antibiotic therapy for patients managed for ventilator-associated pneumonia.

Whole-Genome Sequencing for Molecular Characterization of Carbapenem-Resistant Enterobacteriaceae Causing Lower Urinary Tract Infection among Pediatric Patients

Antibiotic resistance is a growing public health problem globally, incurring health and cost burdens. The occurrence of antibiotic-resistant bacterial infections has increased significantly over the years. Gram-negative bacteria display the broadest resistance range, with bacterial species expressing extended-spectrum β-lactamases (ESBLs), AmpC, and carbapenemases. All carbapenem-resistant Enterobacteriaceae (CRE) isolates from pediatric urinary tract infections (UTIs) between October 2015 and November 2019 (n = 30). All isolates underwent antimicrobial resistance phenotypic testing using the Phoenix NMIC/ID-5 panel, and carbapenemase production was confirmed using the NG-Test CARBA 5 assay. Whole-genome sequencing was performed on the CREs. The sequence type was identified using the Achtman multi-locus sequence typing scheme, and antimicrobial resistance markers were identified using ResFinder and the CARD database. The most common pathogens causing CRE UTIs were E. coli (63.3%) and K. pneumoniae (30%). The most common carbapenemases produced were OXA-48-like enzymes (46.6%) and NDM enzymes (40%). Additionally, one E. coli harbored IMP-26, and two K. pneumoniae possessed mutations in ompK37 and/or ompK36. Lastly, one E. coli had a mutation in the marA porin and efflux pump regulator. The findings highlight the difference in CRE epidemiology in the pediatric population compared to Qatar's adult population, where NDM carbapenemases are more common.

Biochemical characterization of OXA-244, an emerging OXA-48 variant with reduced β-lactam hydrolytic activity

BACKGROUND

OXA-48-producing Enterobacterales have widely disseminated globally with an increasing number of variants identified. Among them, OXA-244 is increasingly reported, despite detection difficulties.

OBJECTIVES

To determine the steady-state kinetic parameters of OXA-244.

METHODS

The blaOXA-244 gene was amplified, cloned into plasmids p-TOPO and pET41b+, and transformed into Escherichia coli TOP10 for MIC determination and E. coli BL21 DE3 for purification. Steady-state kinetic parameters and IC50s of clavulanic acid, tazobactam and NaCl were determined using purified OXA-244. Molecular modelling was also performed.

RESULTS

A reduction in MICs of temocillin and carbapenems was observed in E. coli expressing OXA-244 as compared with OXA-48. The kinetic parameters revealed a reduced carbapenemase activity of OXA-244 as compared with OXA-48, especially for imipenem, which was 10-fold lower. Similarly, catalytic efficiency (kcat/Km) was reduced by 4-fold and 20-fold for ampicillin and temocillin, respectively. Kinetic parameters for cephalosporins were, however, similar. Molecular modelling studies evidenced the key role of R214 in OXA-48, establishing salt bridges with D159 and with the carboxylate group of the R1 substituent of temocillin. These interactions are not possible with G214 in OXA-244, explaining the reduced affinity of temocillin for this enzyme. The R214G mutation in OXA-244 is also likely to induce changes in the active site's water network that would explain the decrease in the hydrolysis rate of carbapenems.

CONCLUSIONS

Our data confirm that the R214G mutation (present in OXA-244) results in reduced carbapenem- and temocillin-hydrolysing activity, confirming the crucial role of residue 214 in the hydrolysis of these substrates by OXA-48-like β-lactamases.

Emergence and Polyclonal Dissemination of OXA-244-Producing Escherichia coli, France

Since 2016, OXA-244-producing Escherichia coli has been increasingly isolated in France. We sequenced 97 OXA-244-producing E. coli isolates and found a wide diversity of sequence types and a high prevalence of sequence type 38. Long-read sequencing demonstrated the chromosomal location of bla_OXA-244 inside the entire or truncated Tn51098.

Screening of OXA-244 producers, a difficult-to-detect and emerging OXA-48 variant?

BACKGROUND

OXA-244, a single amino acid variant of OXA-48, demonstrates weaker hydrolytic activity towards carbapenems and temocillin compared with OXA-48. Of note, these antimicrobials are present in high concentrations in several carbapenemase-producing Enterobacterales (CPE) screening media. As a result, some screening media fail to grow OXA-244-producing isolates, while the prevalence of OXA-244 producers is constantly increasing in France.

METHODS

Here, we evaluate the performance of three commercially available CPE screening media [ChromID® CARBA SMART (bioMérieux), Brilliance™ CRE (Thermo Fisher) and mSuperCARBA™ (MAST Diagnostic)] for their ability to detect OXA-244 producers (n = 101). As OXA-244 producers may also express an ESBL, two additional ESBL screening media were tested (Brilliance™ ESBL and ChromID® BLSE). MICs of temocillin and imipenem were determined by broth microdilution. The clonality of OXA-244-producing Escherichia coli isolates (n = 97) was assessed by MLST.

RESULTS

Overall, the sensitivity of the ChromID® CARBA SMART, Brilliance™ CRE and mSuperCARBA™ media were 14% (95% CI = 8.1%-22.5%), 54% (95% CI = 43.3%-63.4%) and 99% (95% CI = 93.8%-100%), respectively, for the detection of OXA-244 producers. Among the 101 OXA-244-producing isolates, 96% were E. coli and 77%-78% grew on ESBL screening media. MLST analysis identified five main STs among OXA-244-producing E. coli isolates: ST38 (n = 37), ST361 (n = 17), ST69 (n = 12), ST167 (n = 11) and ST10 (n = 8).

CONCLUSIONS

Our results demonstrated that the mSuperCARBA™ medium is very efficient in the detection of OXA-244 producers, unlike the ChromID® CARBA SMART medium. The high prevalence of ESBLs among OXA-244 producers allowed detection of 77%-78% of them using ESBL-specific screening media.

Emergence of carbapenem-resistant ST131 Escherichia coli carrying bla OXA-244 in Germany, 2019 to 2020

The dissemination of carbapenem-producing Gram-negative bacteria is a major public health concern. We report the first detection of OXA-244-producing ST131 O16:H5 Escherichia coli in three patients from two tertiary hospitals in the south-west of Germany. OXA-244 is emerging in Europe. Because of detection challenges, OXA-244-producing E. coli may be under-reported. The emergence of carbapenem resistance in a globally circulating high-risk clone, such as ST131 E. coli is of clinical relevance and should be monitored closely.

Genetic Plurality of OXA/NDM-Encoding Features Characterized From Enterobacterales Recovered From Czech Hospitals

The aim of this study was to characterize four Enterobacterales co-producing NDM- and OXA-48-like carbapenemases from Czech patients with travel history or/and previous hospitalization abroad. Klebsiella pneumoniae isolates belonged to “high risk” clones ST147, ST11, and ST15, while the Escherichia coli isolate was assigned to ST167. All isolates expressed resistance against most β-lactams, including carbapenems, while retaining susceptibility to colistin. Furthermore, analysis of WGS data showed that all four isolates co-produced OXA-48- and NDM-type carbapenemases, in different combinations (Kpn47733: bla_NDM–5 + bla_OXA–181; Kpn50595: bla_NDM–1 + bla_OXA–181; Kpn51015: bla_NDM–1 + bla_OXA–244; Eco52418: bla_NDM–5 + bla_OXA–244). In Kpn51015, the bla_OXA–244 was found on plasmid p51015_OXA-244, while the respective gene was localized in the chromosomal contig of E. coli Eco52418. On the other hand, bla_OXA–181 was identified on a ColKP3 plasmid in isolate Kpn47733, while a bla_OXA–181-carrying plasmid being an IncX3-ColKP3 fusion was identified in Kpn50595. The bla_NDM–1 gene was found on two different plasmids, p51015_NDM-1 belonging to a novel IncH plasmid group and p51015_NDM-1 being an IncF_K1-FIB replicon. Furthermore, the bla_NDM–5 was found in two IncFII plasmids exhibiting limited nucleotide similarity to each other. In both plasmids, the genetic environment of bla_NDM–5 was identical. Finally, in all four carbapenemase-producing isolates, a diverse number of additional replicons, some of these associated with important resistance determinants, like bla_CTX–M–15, arr-2 and ermB, were identified. In conclusion, this study reports the first description of OXA-244-producing Enterobacterales isolated from Czech hospitals. Additionally, our findings indicated the genetic plurality involved in the acquisition and dissemination of determinants encoding OXA/NDM carbapenemases.

Surveillance of OXA-244-producing Escherichia coli and epidemiologic investigation of cases, Denmark, January 2016 to August 2019

Background

Carbapenemase-producing Escherichia coli are increasing worldwide. In recent years, an increase in OXA-244-producing E. coli isolates has been seen in the national surveillance of carbapenemase-producing organisms in Denmark.

Aim

Molecular characterisation and epidemiological investigation of OXA-244-producing E. coli isolates from January 2016 to August 2019.

Methods

For the epidemiological investigation, data from the Danish National Patient Registry and the Danish register of civil registration were used together with data from phone interviews with patients. Isolates were characterised by analysing whole genome sequences for resistance genes, MLST and core genome MLST (cgMLST).

Results

In total, 24 OXA-244-producing E. coli isolates were obtained from 23 patients. Among the 23 patients, 13 reported travelling before detection of the E. coli isolates, with seven having visited countries in Northern Africa. Fifteen isolates also carried an extended-spectrum beta-lactamase gene and one had a plasmid-encoded AmpC gene. The most common detected sequence type (ST) was ST38, followed by ST69, ST167, ST10, ST361 and ST3268. Three clonal clusters were detected by cgMLST, but none of these clusters seemed to reflect nosocomial transmission in Denmark.

Conclusion

Import of OXA-244 E. coli isolates from travelling abroad seems likely for the majority of cases. Community sources were also possible, as many of the patients had no history of hospitalisation and many of the E. coli isolates belonged to STs that are present in the community. It was not possible to point at a single country or a community source as risk factor for acquiring OXA-244-producing E. coli.

NitroSpeed-Carba NP Test for Rapid Detection and Differentiation between Different Classes of Carbapenemases in Enterobacterales

A biochemical test (NitroSpeed-Carba NP test) was developed to identify carbapenemase production in Enterobacterales and to discriminate between the different types of clinically significant carbapenemases (Ambler classes A, B, and D). It is based on two main features, namely, the hydrolysis by all β-lactamases, including carbapenemases of the nitrocefin substrate, and the capacity of ertapenem to prevent this hydrolysis for all β-lactamases except carbapenemases. Specific carbapenemase inhibitors of class A (avibactam, vaborbactam), class B (dipicolinic acid), and class D (avibactam) were used to inhibit the nitrocefin hydrolysis and to allow the identification of the carbapenemase types with a turnaround time of ca. 30 min. The test was evaluated with a collection of 248 clinical enterobacterial isolates, including 148 carbapenemase producers and 100 non-carbapenemase producers. Its overall sensitivity and specificity were 100% and 97%, respectively, including detection of all types of OXA-48-like carbapenemases. For the detection of the carbapenemase type, including strains that produce double carbapenemases, the sensitivity was 100%, 97%, and 100% for the detection of classes A, B, and D, respectively. This easy-to-implement test may contribute to optimization of the choice of the β-lactam/β-lactamase inhibitor combinations for treating infection due to carbapenemase producers.

An MLST approach to support tracking of plasmids carrying OXA-48-like carbapenemase

OBJECTIVES

The prevalence of infections caused by OXA-48-like carbapenemase-producing organisms in Ireland has increased dramatically since 2011 and is an urgent public health issue. Genome-based high-resolution genotyping was used to analyse clinical isolates submitted to the Irish Carbapenemase-Producing Enterobacteriaceae Reference Laboratory Service for a 13 month period (2016-17).

METHODS

A total of 109 OXA-48-producing non-duplicate clinical isolates from 16 submitting centres were sequenced. Using a gene-by-gene approach, isolate genomes were characterized by MLST and core genome MLST, and the presence of antimicrobial resistance determinants was determined. Reference mapping and a novel plasmid MLST-type approach was applied to determine plasmid background.

RESULTS

The OXA-48-like-producing isolates were Escherichia coli (n = 56), Klebsiella spp. (n = 46) and Enterobacter cloacae (n = 7). Amongst the E. coli isolates there were 37 different STs and amongst the Klebsiella spp. isolates there were 27 different STs. blaOXA-48 was present in 105/109 (96.3%) of isolates. Based on mapping analysis and detection of the pOXA-48 IncL-type plasmid replicon and backbone genes, a pOXA-48-like plasmid was identified in 93/109 isolates (85.3%). The remaining isolates (n = 16; 14.7%) harboured blaOXA-48-like genes in unknown environments. Using a gene-by-gene approach two pOXA-48-like plasmid groups with 2/71 pOXA-48-like locus differences between them were identified.

CONCLUSIONS

In Ireland we found a diversity of genotypes associated with OXA-48-like-producing clinical isolates with the IncL pOXA-48 plasmid type predominating as the blaOXA-48 genetic environment. A plasmid MLST approach can rapidly identify plasmids associated with outbreaks and monitor spread of types temporally and geographically.

Draft genome sequence of a blaNDM-1- and blaOXA-244-carrying multidrug-resistant Escherichia coli D-ST69 clinical isolate from Egypt

OBJECTIVES

This study describes the first draft genome sequence of a multidrug-resistant (MDR) Escherichia coli D-ST69 clinical isolate from Egypt carrying bla_NDM-1 and bla_OXA-244.

METHODS

The strain was isolated in December 2014 from a wound pus swab of a male patient in the city of Kafr El-Sheikh using MacConkey agar containing 2 μg/mL meropenem. The strain was subjected to antimicrobial susceptibility testing, conjugation experiments, and whole-genome sequencing using an Illumina MiSeq platform.

RESULTS

The draft genome of the strain (HR14_AS) was 5.08 Mbp in size containing a total of 90 contigs encoding 4677 predicted genes with an average G+C content of 50.7%. Strain HR14_AS belongs to sequence type 69 (ST69), phylogroup D and exhibits an MDR phenotype, with minimum inhibitory concentrations (MICs) of 64 μg/mL and 32 μg/mL for meropenem and doripenem, respectively. Multiple acquired antimicrobial resistance genes conferring resistance to macrolides [mdf(A)], fluoroquinolones [aac(6')-Ib-cr], quinolones (qnrS1), trimethoprim (dfrA14), β-lactams (bla_NDM-1, bla_OXA-244, bla_CTX-M-15, bla_OXA-9 and bla_TEM-1B) and aminoglycosides [aac(3)-IId, aac(6')-Ib, aadA1 and aph(3')-VI] were detected. The bla_OXA-244 and bla_NDM-1 genes were located on the chromosome (Tn6237) and on an IncI1-type self-conjugative plasmid of >93 kb in size, respectively.

CONCLUSIONS

Here we report the first draft genome sequence of a MDR E. coli D-ST69 isolate carrying bla_NDM-1 and bla_OXA-244. Besides clonal expansion of the E. coli ST38 pandemic clone, this study further identified that the spread of OXA-244-producing E. coli could be related to mobilisation of the IS1R-made composite transposon (Tn6237) carrying bla_OXA-244.

Role of Arginine 214 in the Substrate Specificity of OXA-48

Increasing numbers of variants of the carbapenem-hydrolyzing class D β-lactamase OXA-48 are identified in Enterobacterales worldwide. Among them, OXA-181 and OXA-232 are of particular interest, as they differ from each other by a single amino acid substitution at position 214 (R in OXA-181 and S in OXA-232) that results in reduced carbapenem-hydrolyzing activity for OXA-232. To investigate the role of amino acid position 214 (AA214), the X-ray structure of OXA-232 was determined and AA214 of OXA-48 and of OXA-232 was replaced by G, L, D, E, S, R, and K using site-directed mutagenesis. These mutants were phenotypically characterized, and three mutants of OXA-232 were purified to study their steady-state kinetic properties. The X-ray structure of OXA-232 along with molecular modeling studies showed that the interaction via a salt bridge between R214 and D159 in OXA-48 is not possible with the G214 or S214 mutation. In contrast, with K214, which is also positively charged, the interaction with D159 is maintained. With the E214 mutant, an alternative binding conformation of imipenem that is not compatible with a nucleophilic attack by S70 was evidenced. Thus, imipenem has a very poor apparent affinity for the E214 mutant because of its nonproductive binding mode. Similarly, we could explain the lack of temocillin hydrolysis by the OXA-232-S214E mutant, which is due to the unfavorable interaction between the negatively charged R1 substituent of temocillin with the E214 residue. Overall, we demonstrate that AA214 in OXA-48-like β-lactamases is critical for the carbapenemase activity.

Ongoing dissemination of OXA-244 carbapenemase-producing Escherichia coli in Switzerland and their detection

OXA-244 is a derivative of OXA-48 showing weaker carbapenemase activity, compromising the detection of corresponding producers in clinical laboratories. Since 2017, the Swiss National Reference Center for Emerging Antibiotic Resistance noticed an increased identification of OXA-244-producing Escherichia coli (n=15) within the country. Different methods (biochemical and immunoassay tests, screening culture media) were tested for the detection of OXA-244 producers. Whole genome sequencing was used to investigate the genetic relatedness between the isolates and the genetic structures at the origin of the acquisition of the bla_OXA-244 gene. The mSuperCARBA® medium and the NG-Test CARBA5 assay were found to be suitable tools for detecting all OXA-244-producing isolates. Other selective media did not perform optimally. Among the fifteen strains, five sequence types were identified, with ST38 being predominant. The bla_OXA-244 gene was located on the chromosome for all isolates. Overall, detection of OXA-244 producers is challenging and specific guidelines must be followed.

Household cockroaches carry CTX-M-15-, OXA-48- and NDM-1-producing enterobacteria, and share beta-lactam resistance determinants with humans

BACKGROUND

This study was designed to investigate whether household cockroaches harbor cephalosporin-resistant enterobacteria that share resistance determinants with human inhabitants. From February through July 2016, whole cockroach homogenates and human fecal samples from 100 households were cultured for cephalosporin-resistant enterobacteria (CRe). The CRe were examined for plasmid-mediated AmpC, ESBL, and carbapenemase genes; antibiotic susceptibility patterns; and conjugative transfer of antibiotic resistance mechanisms. Clonal associations between CRe were determined by multi-locus sequence typing (MLST).

RESULTS

Twenty CRe were recovered from whole cockroach homogenates from 15 households. The prevalence of households with cockroaches that harbored CRe, AmpC- (based on phenotype, with no identifiable blaAmpC genes), ESBL-, and carbapenemase-producers were 15, 4, 5%(2 bla_{CTX-M-15/TEM-1}; 1 bla_{CTX-M-15/TEM-4}; 1 bla_TEM-24; 1 bla_SHV-4) and 3%(2 bla_NDM-1 genes and 1 bla_OXA-48 gene), respectively. Overall, 20 CRe were recovered from 61 fecal samples of inhabitants from all 15 households that had cockroach samples positive for CRe. Of these, 5CRe (1 per household) were positive for ESBLs (bla_TEM-24, bla_TEM-14, bla_{CTX-M-15/TEM-4}, bla_SHV-3, bla_{CTX-M-15/TEM-1}) and none carried AmpCs or carbapenemases. From 4% of households, the pair of cockroach and human CRe shared the same sequence type (ST), clonal complex (CC), antibiogram, and conjugable bla gene sequence (house 34, E. coli ST9/CC20-bla_TEM-4; house 37, E. coli ST44/CC10-bla_CTX-15/TEM-4; house 41, E. coli ST443/CC205-bla_CTX-15/TEM-1; house 49, K. pneumoniae ST231/CC131-bla_SHV-13).

CONCLUSION

The findings provide evidence that household cockroaches may carry CTX-M-15-, OXA-48- and NDM-1-producers, and share clonal relationship and beta-lactam resistance determinants with humans.

The Global Ascendency of OXA-48-Type Carbapenemases

Surveillance studies have shown that OXA-48-like carbapenemases are the most common carbapenemases in Enterobacterales in certain regions of the world and are being introduced on a regular basis into regions of nonendemicity, where they are responsible for nosocomial outbreaks. OXA-48, OXA-181, OXA-232, OXA-204, OXA-162, and OXA-244, in that order, are the most common enzymes identified among the OXA-48-like carbapenemase group. OXA-48 is associated with different Tn1999 variants on IncL plasmids and is endemic in North Africa and the Middle East. OXA-162 and OXA-244 are derivatives of OXA-48 and are present in Europe. OXA-181 and OXA-232 are associated with ISEcp1, Tn2013 on ColE2, and IncX3 types of plasmids and are endemic in the Indian subcontinent (e.g., India, Bangladesh, Pakistan, and Sri Lanka) and certain sub-Saharan African countries. Overall, clonal dissemination plays a minor role in the spread of OXA-48-like carbapenemases, but certain high-risk clones (e.g., Klebsiella pneumoniae sequence type 147 [ST147], ST307, ST15, and ST14 and Escherichia coli ST38 and ST410) have been associated with the global dispersion of OXA-48, OXA-181, OXA-232, and OXA-204. Chromosomal integration of bla _OXA-48 within Tn6237 occurred among E. coli ST38 isolates, especially in the United Kingdom. The detection of Enterobacterales with OXA-48-like enzymes using phenotypic methods has improved recently but remains challenging for clinical laboratories in regions of nonendemicity. Identification of the specific type of OXA-48-like enzyme requires sequencing of the corresponding genes. Bacteria (especially K. pneumoniae and E. coli) with bla _OXA-48, bla _OXA-181, and bla _OXA-232 are emerging in different parts of the world and are most likely underreported due to problems with the laboratory detection of these enzymes. The medical community should be aware of the looming threat that is posed by bacteria with OXA-48-like carbapenemases.

First Report and Comparative Genomics Analysis of a blaOXA-244-Harboring Escherichia coli Isolate Recovered in the American Continent

The carbapenemase OXA-244 is a derivate of OXA-48, and its detection is very difficult in laboratories. Here, we report the identification and genomic analysis of an Escherichia coli isolate (28Eco12) harboring the bla_OXA-244 gene identified in Colombia, South America. The 28Eco12 isolate was identified during a retrospective study, and it was recovered from a patient treated in Colombia. The complete nucleotide sequence was established using the PacBio platform. A comparative genomics analysis with other bla_OXA-244–harboring Escherichia coli strains was performed. The 28Eco12 isolate belonged to sequence type (ST) 38, and its genome was composed of two molecules, a chromosome of 5,343,367 bp and a plasmid of 92,027 bp, which belonged to the incompatibility group IncY and did not harbor resistance genes. The bla_OXA-244 gene was chromosomally encoded and mobilized by an ISR1-related Tn6237 composite transposon. Notably, this transposon was inserted and located within a new genomic island. To our knowledge, this is the first report of a bla_OXA-244–harboring Escherichia coli isolate in America. Our results suggest that the introduction of the OXA-244-producing E. coli isolate was through clonal expansion of the ST38 pandemic clone. Other isolates producing OXA-244 could be circulating silently in America.

In Vitro Activity of Ceftazidime-Avibactam and Aztreonam-Avibactam against OXA-48-Carrying Enterobacteriaceae Isolated as Part of the International Network for Optimal Resistance Monitoring (INFORM) Global Surveillance Program from 2012 to 2015

Enterobacteriaceae producing the Ambler class D OXA-48 carbapenemase, combined with additional resistance mechanisms, such as permeability defects or cocarriage of class A, B, or C β-lactamases, can become highly resistant to most β-lactams currently in use, including carbapenems. A total of 45,872 Enterobacteriaceae clinical isolates collected in 39 countries as part of the International Network for Optimal Resistance Monitoring (INFORM) global surveillance study in 2012 to 2015 were tested for susceptibility to β-lactams and comparator agents using the Clinical and Laboratory Standards Institute broth microdilution methodology and screened for the presence of β-lactamases. The bla _OXA-48 and bla _OXA-48-like genes were detected in 333 isolates across 14 species of Enterobacteriaceae collected in 20 countries across the globe. Few agents tested were effective in vitro against the overall collection of OXA-48-producers (n = 265), with tigecycline (MIC₉₀, 2 µg/ml; 92.5% susceptible), ceftazidime-avibactam (MIC₉₀, 4 µg/ml; 92.5% susceptible), and aztreonam-avibactam (MIC₉₀, 0.5 µg/ml; 99.6% of isolates with MIC ≤8 µg/ml) demonstrating the greatest activity. Similarly, colistin (MIC₉₀, 1 µg/ml; 94.2% susceptible), tigecycline (MIC₉₀, 2 µg/ml; 92.6% susceptible), ceftazidime-avibactam (MIC₉₀, >128 µg/ml; 89.7% susceptible), and aztreonam-avibactam (MIC₉₀, 4 µg/ml; 100% of isolates with MIC ≤8 µg/ml) were most active against OXA-48-like-positive isolates (n = 68). The in vitro activity of ceftazidime-avibactam was improved against the subset of metallo-β-lactamase (MBL)-negative, OXA-48- and OXA-48-like-positive isolates (99.2% and 100% susceptible, respectively). The data reported here support the continued investigation of ceftazidime-avibactam and aztreonam-avibactam for the treatment of infections caused by carbapenem-resistant Enterobacteriaceae carrying OXA-48 and OXA-48-like β-lactamases in combination with serine- or metallo-β-lactamases.

Carbapenemase-Producing Organisms: A Global Scourge

The dramatic increase in the prevalence and clinical impact of infections caused by bacteria producing carbapenemases is a global health concern. Carbapenemase production is especially problematic when encountered in members of the family Enterobacteriaceae. Due to their ability to readily spread and colonize patients in healthcare environments, preventing the transmission of these organisms is a major public health initiative and coordinated international effort are needed. Central to the treatment and control of carbapenemase-producing organisms (CPOs) are phenotypic (growth-/biochemical-dependent) and nucleic acid-based carbapenemase detection tests that identify carbapenemase activity directly or their associated molecular determinants. Importantly, bacterial isolates harboring carbapenemases are often resistant to multiple antibiotic classes, resulting in limited therapy options. Emerging agents, novel antibiotic combinations and treatment regimens offer promise for management of these infections. This review highlights our current understanding of CPOs with emphasis on their epidemiology, detection, treatment, and control.

Detection of different classes of carbapenemases: Adaptation and assessment of a phenotypic method applied to Enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter baumannii, and proposal of a new algorithm

A new phenotypic method for detecting carbapenemases has been adapted (assembling of two MAST® kits, including one that contains faropenem to which a temocillin disk has been added) then assessed using 101 bacterial strains (Enterobacteriaceae with assays on Pseudomonas aeruginosa and Acinetobacter baumannii) including 62 which produce genetically identified carbapenemases. Concerning Carbapenemase-Producing Enterobacteriaceae (CPE), there is 100% sensitivity for Klebsiella pneumoniae carbapenemase (KPC, Ambler class A) and OXA-48 (Ambler class D), and 91% for metallo-beta-lactamase (MBL, Ambler class B), with a 97% sensitivity for all carbapenemases, with a specificity of 100%. The test is also efficient for detecting Pseudomonas aeruginosa carbapenemases (sensitivity between 82 and 100% and 100% specificity). The major innovation is the combined use of faropenem and temocillin for reliable detection (excellent performance with 100% sensitivity and specificity) of OXA-48. This study has led to the development of a new algorithm to detect the different classes of carbapenemases, for first-line diagnosis, by combining this modified MAST® test with immunochromatographic methods and molecular biology techniques.

Analysis of OXA-204 carbapenemase-producing Enterobacteriaceae reveals possible endoscopy-associated transmission, France, 2012 to 2014

OXA-48-like beta-lactamase producing bacteria are now endemic in several European and Mediterranean countries. Among this carbapenemase family, the OXA-48 and OXA-181 variants predominate, whereas other variants such as OXA-204 are rarely reported. Here, we report the molecular epidemiology of a collection of OXA-204-positive enterobacterial isolates (n = 29) recovered in France between October 2012 and May 2014. This study describes the first outbreak of OXA-204-producing Enterobacteriaceae in Europe, involving 12 isolates of an ST90 Escherichia coli clone and nine isolates of an ST147 Klebsiella pneumoniae clone. All isolates co-produced the cephalosporinase CMY-4, and 60% of them co-produced the extended-spectrum beta-lactamase CTX-M-15. The bla_OXA-204 gene was located on a 150-kb IncA/C plasmid, isolated from various enterobacterial species in the same patient, indicating a high conjugative ability of this genetic vehicle.

Characterization of OXA-48-like-producing Enterobacteriaceae isolated from river water in Algeria

The spread of carbapenemase-producing Enterobacteriaceae (CPE) is a significant problem for healthcare worldwide. The prevalence of carbapenem-resistant Enterobacteriaceae (CPE) in water environments in Algeria are unknown. The aim of this study was to screen for the presence of CPE isolates in the Soummam River in Bejaia, Algeria. Isolates of Enterobacteriaceae recovered from twelve samples of river water and showing reduced susceptibility to carbapenems were included in this study. The isolates were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Isolates were subjected to antimicrobial susceptibility testing and the modified Carba NP test. Carbapenemase and extended-spectrum β-lactamase (ESBL) determinants were studied by PCR amplification and sequencing. The clonal relatedness between isolates was studied by Multilocus Sequence Typing (MLST) method. A total of 20 carbapenem-resistant Enterobacteriaceae strains were included in this study, identified as Escherichia coli (n = 12), Klebsiella pneumoniae (n = 3), Raoultella ornithinolytica (n = 3), Citrobacter freundii (n = 1) and Citrobacter braakii (n = 1). Carbapenemase genes identified in this study included bla_OXA-48, observed in 17 isolates (9 E. coli, 3 K. pneumoniae, 3 R. ornithinolytica, 1 C. freundii and 1 C. braakii), and bla_OXA-244, a variant of bla_OXA-48, was found in three E. coli isolates. MLST showed that 12 E. coli strains belonged to six different sequence types (ST559, ST38, ST212, ST3541, 1972 and ST2142), and we identified three different STs in K. pneumoniae isolates, including ST133, ST2055, and a new sequence type: ST2192. This study showed the presence of OXA-48-like-producing Enterobacteriaceae in water environments and highlighted the potential role of aquatic environments as reservoirs of clinically relevant antimicrobial-resistant bacteria, with the potential to spread throughout the community.

Multicentre evaluation of the BYG Carba v2.0 test, a simplified electrochemical assay for the rapid laboratory detection of carbapenemase-producing Enterobacteriaceae

Rapid detection of carbapenemase-producing Enterobacteriaceae (CPE) represents a major challenge for microbiology laboratories. We evaluated the BYG Carba v2.0 using a simplified protocol, which detects CPE in less than 30 minutes. This new procedure reduces the hands-on-time from 5 to one minute and only requires a limited amount of material (one to three colonies) thereby preventing the need for subculturing bacterial isolates to reach a larger amount of pure biomass. This multicentre study involved four European reference laboratories. For the 1181 isolates tested across four centres, BYG Carba v2.0 yielded overall sensitivity and specificity of 96.3% (CI95: 94.5–97.5) and 99.7% (CI95: 98.6–100) respectively. Considering only the 670 consecutive isolates tested prospectively, the BYG Carba v2.0 displayed overall positive and negative predictive values of 99.7% (CI95: 95.4–98.9) and 97.5% (CI95: 94.9–98.8). Regarding time to positivity, 85% of CPE detected were positive within ten minutes. The BYG Carba v2.0 is a new highly simplified, rapid and accurate electrochemical assay discriminating between CPE and non-CPE in less than 30 min. The real-time quantified signal allows objective and traceable interpretation of the results.

OXA-244-Producing Escherichia coli Isolates, a Challenge for Clinical Microbiology Laboratories

OXA-244 is a single-point-mutant derivative of OXA-48 displaying reduced carbapenemase activity. Here, we report the microbiological features of seven OXA-244-producing Escherichia coli isolates. Only one isolate grew on ChromID Carba Smart medium (bioMérieux), but six of the seven isolates grew on ChromID extended-spectrum-β-lactamase (ESBL) medium (bioMérieux), as they coproduced an ESBL and/or a plasmid-encoded cephalosporinase. The production of a carbapenemase was detected in 57.1%, 71.4%, 71.4%, and 100% of the E. coli isolates using the Carba NP test, the Rapidec Carba NP test (bioMérieux), a matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) hydrolysis assay (Bruker), and the OXA-48 K-SeT assay (Coris BioConcept), respectively. Our results indicate that OXA-244-producing E. coli isolates are difficult to detect, which may lead to their silent spread.

Dissemination of bla OXA-370 gene among several Enterobacteriaceae species in Brazil

OXA-370 is a recently described OXA-48 variant that has only been described in a few Enterobacter spp. and Klebsiella pneumoniae isolates. The purpose of this study is to assess the prevalence of OXA-370-producing isolates in carbapenem-nonsusceptible Enterobacteriaceae recovered from 28 hospitals from Brazil. Real-time PCR was used to determine the presence of bla _NDM-1, bla _KPC-2, bla _VIM-type, bla _GES-type, bla _OXA-48-like, and bla _IMP-type genes. A total of 4,451 Enterobacteriaceae were screened. The gene bla _OXA-48-like was detected in 74 (2.5%) isolates, mostly of Enterobacter spp. (44.6% E. cloacae and 2.7% E. aerogenes) and Klebsiella spp. (31.1% K. pneumoniae and 6.7% K. oxytoca), followed by Escherichia coli, (6.7%), Morganella morganii, (2.7%), Citrobacter freundii (1.3%), Proteus mirabilis (1.3%), Providencia stuartii (1.3%), and Serratia spp. (1.3%). These isolates were from five hospitals, 67 (90.5%) from the hospital where the bla _OXA-370 was first described. Sequencing of bla _OXA-48-like was performed in 52 isolates, including E. cloacae, E. aerogenes, K. pneumoniae, K. oxytoca, E. coli, and C. freundii; all presenting 100% identity with bla _OXA-370. PFGE revealed the presence of distinct clones among K. pneumoniae, E. cloacae, K. oxytoca, and E. coli. Susceptibility rates to meropenem, imipenem, and ertapenem among OXA-370-producing isolates were 92.3%, 78.8%, 7.7% respectively; the MIC₅₀ /MIC₉₀ were 0.38/2 mg/L and 1/3 mg/L for meropenem and imipenem respectively. Overall, antimicrobial susceptibility analysis suggests that OXA-370 lacks carbapenemase activity. Our study demonstrated that the bla _OXA-370 gene is disseminated among several Enterobacteriaceae species and clones, indicating a high potential for dissemination.

Intestinal carriage of multidrug-resistant gram-negative bacteria in preterm-infants during hospitalization in neonatal intensive care unit (NICU)

The prevalence and antibiotic susceptibility of intestinal carriage of Gram-negative bacteria among preterm infants admitted to the neonatal intensive care unit (NICU) in a tertiary teaching hospital in Malaysia were determined. A total of 34 stool specimens were obtained from preterm infants upon admission and once weekly up to two weeks during hospitalization. The presumptive colonies of Escherichia coli and Klebsiella pneumoniae were selected for identification, antibiotic susceptibility testing, and subtyping by using pulsed-field gel electrophoresis (PFGE). Out of 76 Gram-negative isolates, highest resistance was detected for amoxicillin/clavulanate (30.8%, n = 16), ceftriaxone (42.3%, n = 22), ceftazidime (28.8%, n = 15), cefoxitin (28.8%, n = 15), aztreonam (36.5%, n = 19), and polymyxin B (23.1%, n = 12). Three colistin resistant K. pneumoniae have also been detected based on E-test analysis. Thirty-nine isolates of K. pneumoniae and 20 isolates of E. coli were resistant to more than three antimicrobial classes and were categorized as multidrug resistant (MDR). PFGE analysis revealed a higher diversity in pulsotypes for K. pneumoniae (18 pulsotypes) in comparison to E. coli (four pulsotypes). In addition, a total of fifteen pulsotypes was observed from 39 MDR K. pneumoniae. The risk factors for antibiotic resistance were assessed using random forest analysis. Gender was found to be the most important predictor for colistin resistant while length, OFC, and delivery mode were showing greater predictive power in the polymyxin B resistance. This study revealed worrying prevalence rates of intestinal carriage of multidrug-resistant K. pneumoniae and E. coli of hospitalized preterm infants in Malaysia, particularly high resistance to polymyxins.

Prolonged carriage and potential onward transmission of carbapenemase-producing Enterobacteriaceae in Dutch travelers

AIM

The aim was to study acquisition and persistence of carbapenemase-producing Enterobacteriaceae (CPE) among travelers.

MATERIALS & METHODS

Stools from 2001 travelers and 215 nontraveling household members, collected before and immediately post-travel as well as 1, 3, 6 and 12 months upon return, were screened for CPE.

RESULTS

Five travelers, all visiting Asia outside the Indian subcontinent, acquired CPE. One traveler persistently carried the same OXA-244 CPE up to 6 months post-travel. Three months after travel, her co-traveling spouse also became positive for this OXA-244 CPE strain, suggesting clonal transmission within this household.

CONCLUSION

Acquisition of CPE is not restricted to travelers to the Indian subcontinent and/or to travelers seeking healthcare during travel and can persist up to at least 6 months post-travel.