Characterisation of carbapenemase-producing Acinetobacter baumannii isolates from danish patients 2014-2021: detection of a new international clone - IC11.

OBJECTIVES: This study aimed to characterise carbapenemase-producing Acinetobacter baumannii (A. baumannii) isolates from Danish patients using whole genome sequencing (WGS). It also compared typing and epidemiological data for further investigation of the spread and origin of the carbapenemase-producing A. baumannii isolates. METHODS: From 1 January 2014 to 30 September 2021, 141 carbapenemase-producing A. baumannii isolates, received at the national reference laboratory at Statens Serum Institut, were investigated using WGS. Multilocus sequence typing (MLST) and cgMLST data, obtained by SeqSphere+ software, were linked to data related to source of isolation, patient age and sex, hospital admission and travel history. RESULTS: Most of the carbapenemase-producing A. baumannii isolates were from males (n = 100, 71%). Most patients (n = 88, 63%) had travelled outside Scandinavia before admission to a Danish hospital. The most prevalent carbapenemase gene was blaOXA-23 (n = 124). Isolates belonging to the dominating international clone IC2 accounted for 78% of all isolates. A new international ST164/OXA-91 clone, proposed to be named IC11, was recognised and described. The cgMLST analysis revealed 17 clusters, reflecting both sporadic travel to similar geographical areas and confirmed outbreaks in Danish hospitals. CONCLUSIONS: The occurrence of carbapenemase-producing A. baumannii in Denmark was still low; however, isolates belonging to major international clones with a high potential to spread within hospitals, mainly IC2, dominated. OXA-23 was by far the most prevalent carbapenemase detected. Sporadic and travel-related introductions to Danish hospitals, also intra-hospital transmission, could be confirmed, emphasising the need for continuing vigilance.

Contaminated dicloxacillin capsules as the source of an NDM-5/OXA-48-producing Enterobacter hormaechei ST79 outbreak, Denmark and Iceland, 2022 and 2023.

From October 2022 through January 2023, nine patients with NDM-5/OXA-48-carbapenemase-producing Enterobacter hormaechei ST79 were detected in Denmark and subsequently one patient in Iceland. There were no nosocomial links between patients, but they had all been treated with dicloxacillin capsules. An NDM-5/OXA-48-carbapenemase-producing E. hormaechei ST79, identical to patient isolates, was cultured from the surface of dicloxacillin capsules in Denmark, strongly implicating them as the source of the outbreak. Special attention is required to detect the outbreak strain in the microbiology laboratory.

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

BackgroundCarbapenemase-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.AimMolecular characterisation and epidemiological investigation of OXA-244-producing E. coli isolates from January 2016 to August 2019.MethodsFor 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).ResultsIn 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.ConclusionImport 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.

Investigation of possible clonal transmission of carbapenemase-producing Klebsiella pneumoniae complex member isolates in Denmark using core genome MLST and National Patient Registry Data.

OBJECTIVES: The aim of this study was to identify clonally-related carbapenemase-producing Klebsiella pneumoniae complex members that could be involved in outbreaks among hospitalized patients in Denmark, and to identify possible epidemiological links. METHODS: From January 2014 to June 2018, 103 isolates belonging to the K. pneumoniae complex were collected from 102 patients. From the whole-genome sequencing (WGS) data, presence of genes encoding carbapenemase and multilocal sequence typing (MLST) data were extracted. Core genome MLST (cgMLST) cluster analysis was performed. Using data from the Danish National Patient Registry (DNPR) and reported travel history, presumptive outbreaks were investigated for possible epidemiological links. RESULTS: The most common detected carbapenemase gene was blaOXA-48, followed by blaNDM-1. The 103 K. pneumoniae complex isolates belonged to 47 sequence types (STs) and cgMLST subdivided the isolates into 80 different complex types. cgMLST identified 13 clusters with 2-4 isolates per cluster. For five of the 13 clusters, a direct link (the patients stayed at the same ward on the same day) could be detected between at least some of the patients. In two clusters, the patients resided simultaneously at the same hospital, but not the same ward. A possible link (same ward within 1-13 days) was detected for the patients in one cluster. For five clusters detected by cgMLST, no epidemiological link could be detected using data from DNPR. CONCLUSION: In this study, cgMLST combined with patient hospital admission data and travel information was found to be a reliable and detailed approach to detect possible clonal transmission of carbapenemase-producing K. pneumoniae complex members.

Characterization of Diarrheagenic Enteroaggregative Escherichia coli in Danish Adults-Antibiotic Treatment Does Not Reduce Duration of Diarrhea.

Enteroaggregative Escherichia coli (EAEC) is frequently isolated from sporadic cases of diarrhea and in outbreaks of gastroenteritis in several regions of the world. The pathophysiology of EAEC continues to be enigmatic, and the efficacy of antibiotic treatment in EAEC-associated diarrhea has been discussed. Since the level of antibiotic resistance is increasing, it is essential to restrict the use of antibiotics to prevent further resistance development. We aimed to investigate EAEC strains in adult Danish patients suffering from diarrhea and from healthy controls. We examined the antibiotic resistance in EAEC strains, the clinical response to antibiotic treatment in EAEC diarrheal cases, and the distribution of virulence genes in diarrheal cases. The EAEC strains were collected from patients suffering from diarrhea in a Danish multicenter study. A medical doctor interviewed the patients by using a questionnaire regarding gastrointestinal symptoms, exposures, and use of antibiotic and over-the-counter antidiarrheal drugs. Follow-up was performed after 3-5 months to inquire about differential diagnosis to gastrointestinal disease. A multiplex polymerase chain reaction characterized virulence genes in diarrheal cases. Finally, the level of antibiotic resistance was examined by using the disc diffusion method. Asymptomatic carriage of EAEC in the adult Danish population was rare, in contrast to findings in healthy Danish children. The duration of diarrhea was not shortened by antibiotic treatment, specifically ciprofloxacin treatment, or by over-the-counter antidiarrheal drugs. Follow-up revealed no pathology in diarrheal patients apart from irritable bowel syndrome in two patients. A high number of patients suffered from long-term diarrhea, which was associated with the enterotoxin EAST-1 and a high virulence factor score. A high level of antibiotic resistance was observed and 58% of the EAEC strains were multidrug resistant. Multidrug resistance was most pronounced in cases of travelers' diarrhea, and it was seen that antibiotic treatment did not reduce the duration of diarrhea.

Association between antimicrobial resistance and virulence genes in Escherichia coli obtained from blood and faeces.

Escherichia coli isolates obtained from faeces (n=85) and blood (n=123) were susceptibility tested against 17 antimicrobial agents and the presence of 9 virulence genes was determined by PCR. Positive associations between several antimicrobial resistances and 2 VF genes (iutA and traT) were found among blood isolates, sometimes among faecal isolates.

Detection of sul1, sul2 and sul3 in sulphonamide resistant Escherichia coli isolates obtained from healthy humans, pork and pigs in Denmark.

The occurrence of sulphonamide resistance was investigated in 998 Escherichia coli isolates, obtained from pig faeces collected at slaughter, Danish pork collected at retail outlets and from faeces from healthy persons in Denmark. In total 18% (n=35), 20% (n=38) and 26% (n=161) of the E. coli isolates obtained from humans, pork and pigs, respectively, were resistant to sulphonamide. All sulphonamide resistant E. coli isolates were investigated for the presence of sul1, sul2, sul3 and intI1 genes by PCR. The sul1 gene was detected in 40% (n=14), 29% (n=11) and 55% (n=88) of the sulphonamide resistant isolates from humans, pork and pigs, respectively. The sul2 gene was detected in 80% (n=28), 76% (n=29) and 50% (n=81) of isolates from humans, pork and pigs, respectively. None of the human isolates were PCR-positive for sul3, whereas sul3 was present in 5% of the pork isolates and 11% of the pig isolates. Of the 113 sul1 positive isolates, 97 carried the integron-associated integrase gene intI1. All 20 sul3 positive isolates were positive for intI1, and in 12 of these isolates sul3 was the only sulphonamide resistance gene detected. The origin of sul1 and sul2 found in isolates from healthy humans is speculative, but their spread from pigs to humans via the food chain is possible.