Spread of carbapenemase-producing Morganella spp from 2013 to 2021: a comparative genomic study.

BACKGROUND: Morganella spp are opportunistic pathogens involved in various infections. Intrinsic resistance to multiple antibiotics (including colistin) combined with the emergence of carbapenemase producers reduces the number of active antimicrobials. The aim of this study was to characterise genetic features related to the spread of carbapenem-resistant Morganella spp. METHODS: This comparative genomic study included extensively drug-resistant Morganella spp isolates collected between Jan 1, 2013, and March 1, 2021, by the French National Reference Center (NRC; n=68) and European antimicrobial resistance reference centres in seven European countries (n=104), as well as one isolate from Canada, two reference strains from the Pasteur Institute collection (Paris, France), and two colistin-susceptible isolates from Bicêtre Hospital (Kremlin-Bicêtre, France). The isolates were characterised by whole-genome sequencing, antimicrobial susceptibility testing, and biochemical tests. Complete genomes from GenBank (n=103) were also included for genomic analysis, including phylogeny and determination of core genomes and resistomes. Genetic distance between different species or subspecies was performed using average nucleotide identity (ANI). Intrinsic resistance mechanisms to polymyxins were investigated by combining genetic analysis with mass spectrometry on lipid A. FINDINGS: Distance analysis by ANI of 275 isolates identified three groups: Morganella psychrotolerans, Morganella morganii subspecies sibonii, and M morganii subspecies morganii, and a core genome maximum likelihood phylogenetic tree showed that the M morganii isolates can be separated into four subpopulations. On the basis of these findings and of phenotypic divergences between isolates, we propose a modified taxonomy for the Morganella genus including four species, Morganella psychrotolerans, Morganella sibonii, Morganella morganii, and a new species represented by a unique environmental isolate. We propose that M morganii include two subspecies: M morganii subspecies morganii (the most prevalent) and M morganii subspecies intermedius. This modified taxonomy was supported by a difference in intrinsic resistance to tetracycline and conservation of metabolic pathways such as trehalose assimilation, both only present in M sibonii. Carbapenemase producers were mostly identified among five high-risk clones of M morganii subspecies morganii. The most prevalent carbapenemase corresponded to NDM-1, followed by KPC-2, and OXA-48. A cefepime-zidebactam combination was the most potent antimicrobial against the 172 extensively drug-resistant Morganella spp isolates in our collection from different European countries, which includes metallo-ß-lactamase producers. Lipid A analysis showed that the intrinsic resistance to colistin was associated with the presence of L-ARA4N on lipid A. INTERPRETATION: This global characterisation of, to our knowledge, the widest collection of extensively drug-resistant Morganella spp highlights the need to clarify the taxonomy and decipher intrinsic resistance mechanisms, and paves the way for further genomic comparisons. FUNDING: None.

Presence of hypervirulence-associated determinants in Klebsiella pneumoniae from hospitalised patients in Germany.

BACKGROUND: Klebsiella (K.) pneumoniae is a ubiquitous Gram-negative bacterium and a common coloniser of animals and humans. Today, K. pneumoniae is one of the most persistent nosocomial pathogens worldwide and poses a severe threat/burden to public health by causing urinary tract infections, pneumonia and bloodstream infections. Infections mainly affect immunocompromised individuals and hospitalised patients. In recent years, a new type of K. pneumoniae has emerged associated with community-acquired infections such as pyogenic liver abscess in otherwise healthy individuals and is therefore termed hypervirulent K. pneumoniae (hvKp). The aim of this study was the characterisation of K. pneumoniae isolates with properties of hypervirulence from Germany. METHODS: A set of 62 potentially hypervirulent K. pneumoniae isolates from human patients was compiled. Inclusion criteria were the presence of at least one determinant that has been previously associated with hypervirulence: (I) clinical manifestation, (II) a positive string test as a marker for hypermucoviscosity, and (III) presence of virulence associated genes rmpA and/or rmpA2 and/or magA. Phenotypic characterisation of the isolates included antimicrobial resistance testing by broth microdilution. Whole genome sequencing (WGS) was performed using Illumina® MiSeq/NextSeq to investigate the genetic repertoire such as multi-locus sequence types (ST), capsule types (K), further virulence associated genes and resistance genes of the collected isolates. For selected isolates long-read sequencing was applied and plasmid sequences with resistance and virulence determinants were compared. RESULTS: WGS analyses confirmed presence of several signature genes for hvKp. Among them, the most prevalent were the siderophore loci iuc and ybt and the capsule regulator genes rmpA and rmpA2. The most dominant ST among the hvKp isolates were ST395 capsule type K2 and ST395 capsule type K5; both have been described previously and were confirmed by our data as multidrug-resistant (MDR) isolates. ST23 capsule type K1 was the second most abundant ST in this study; this ST has been described as commonly associated with hypervirulence. In general, resistance to beta-lactams caused by the production of extended-spectrum beta-lactamases (ESBL) and carbapenemases was observed frequently in our isolates, confirming the threatening rise of MDR-hvKp strains. CONCLUSIONS: Our study results show that K. pneumoniae strains that carry several determinants of hypervirulence are present for many years in Germany. The detection of carbapenemase genes and hypervirulence associated genes on the same plasmid is highly problematic and requires intensified screening and molecular surveillance. However, the non-uniform definition of hvKp complicates their detection. Testing for hypermucoviscosity alone is not specific enough to identify hvKp. Thus, we suggest that the classification of hvKp should be applied to isolates that not only fulfil phenotypical criteria (severe clinical manifestations, hypermucoviscosity) but also (I) the presence of at least two virulence loci e.g. iuc and ybt, and (II) the presence of rmpA and/or rmpA2.

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.

In Vitro Activity of Two Novel Antimicrobial Compounds on MDR-Resistant Clinical Isolates.

The development of novel antibiotics is mandatory to curb the growing antibiotic resistance problem resulting in difficult-to-treat bacterial infections. Here, we have determined the spectrum of activity of cystobactamids and chelocardins, two novel and promising classes of molecules with different modes of action. A panel of 297 clinically relevant Gram-negative and Gram-positive isolates with different antibiotic susceptibility profiles, going from wild type to multi- or even extremely drug resistant (MDR, XDR) and including carbapenem-resistant isolates, were tested using broth microdilution assays to determine the minimal inhibitory concentrations (MICs), MIC50s and MIC90s of two cystobactamids derivatives (CN-861-2 and CN-DM-861) and two chelocardin derivatives (CHD and CDCHD). Cystobactamids revealed potent activities on the majority of tested Enterobacterales (MIC50s ranging from 0.25 to 4 µg/mL), except for Klebsiella pneumoniae isolates (MIC50s is 128 µg/mL). Pseudomonas aeruginosa and Acinetobacter baumannii showed slightly higher MIC50s (4 µg/mL and 8 µg/mL, respectively) for cystobactamids. Chelocardins inhibited the growth of Enterobacterales and Stenotrophomas maltophilia at low to moderate MICs (0.25-16 µg/mL) and the chemically modified CDCHD was active at lower MICs. A. baumannii and P. aeruginosa were less susceptible to these molecules with MICs ranging from 0.5 to 32 µg/mL. These molecules show also interesting in vitro efficacies on clinically relevant Gram-positive bacteria with MICs of 0.125-8 µg/mL for cystobactamids and 0.5-8 µg/mL for chelocardins. Taken together, the cystobactamid CN-DM-861 and chelocardin CDCHD showed interesting antibiotic activities on MDR or XDR bacteria, without cross-resistance to clinically relevant antibiotics such as carbapenems, fluoroquinolones, and colistin.

Rapid cross-border emergence of NDM-5-producing Escherichia coli in the European Union/European Economic Area, 2012 to June 2022.

Whole genome sequencing data of 874 Escherichia coli isolates carrying bla NDM-5 from 13 European Union/European Economic Area countries between 2012 and June 2022 showed the predominance of sequence types ST167, ST405, ST410, ST361 and ST648, and an increasing frequency of detection. Nearly a third (30.6%) of these isolates were associated with infections and more than half (58.2%) were predicted to be multidrug-resistant. Further spread of E. coli carrying bla NDM-5 would leave limited treatment options for serious E. coli infections.

In Vitro Activity of Cefiderocol against Clinical Gram-Negative Isolates Originating from Germany in 2016/17.

Antimicrobial resistance poses a global threat to public health. Of great concern are Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacterales with resistance to carbapenems or third-generation cephalosporins. The aim of the present study was to investigate the in vitro activity of the novel siderophore cephaloporin cefiderocol (CID) and four comparator ß-lactam-ß-lactamase-inhibitor combinations and to give insights into the genetic background of CID-resistant isolates. In total, 301 clinical Enterobacterales and non-fermenting bacterial isolates were selected for this study, including randomly chosen isolates (set I, n = 195) and challenge isolates (set II, n = 106; enriched with ESBL and carbapenemase producers, as well as colistin-resistant isolates). Isolates displayed CID MIC50/90 values of 0.12/0.5 mg/L (set I) and 0.5/1 mg/L (set II). Overall, the CID activity was superior to the comparators against A. baumannii, Stenotrophomonas maltophilia and set II isolates of P. aeruginosa. There were eight CID-resistant isolates detected (MIC > 2 mg/L): A. baumannii (n = 1), E. cloacae complex (n = 5) and P. aeruginosa (n = 2). Sequencing analyses of these isolates detected the acquired ß-lactamase (bla) genes blaNDM-1,blaSHV-12 and naturally occurring blaOXA-396, blaACT-type and blaCMH-3. In conclusion, CID revealed potent activity against clinically relevant organisms of multidrug-resistant Enterobacterales and non-fermenters.

Performance evaluation of the UMIC® Cefiderocol to determine MIC in Gram-negative bacteria.

BACKGROUND: Cefiderocol is a catechol-substituted cephalosporin with potent in vitro activity against carbapenem-resistant (CR) Gram-negative bacteria (GNB). Cefiderocol susceptibility testing is complex because iron concentrations need to be taken into consideration. Here, we assessed the clinical performance of Bruker's UMIC® Cefiderocol and corresponding iron-depleted CAMHB to determine MIC by broth microdilution (BMD) for clinically relevant GNB. METHODS: MICs of cefiderocol for 283 GN clinical isolates were determined by BMD using iron-depleted CAMHB. Frozen panels were used as a reference. The concentration range of cefiderocol was 0.03-32 mg/L. The isolates, with different degrees of susceptibility to cefiderocol, included Enterobacterales (n = 180), Pseudomonas aeruginosa (n = 49), Acinetobacter baumannii (n = 44) and Stenotrophomonas maltophilia (n = 10). RESULTS: The rates of categorical agreement (CA), essential agreement (EA) and bias were calculated to evaluate the performance of the UMIC® Cefiderocol, as compared with the reference method. Overall, the UMIC® Cefiderocol showed 90.8% EA (95% CI: 86.9%-93.7%) with a bias of -14.5% and a CA of 90.1% (95% CI: 86.1%-93.1%). For Enterobacterales, the UMIC® Cefiderocol showed 91.7% EA (95% CI: 86.7%-94.9%) with a bias of -25.0% and a CA of 87.8% (95% CI: 82.2%-91.8%). For non-fermenters, the UMIC® Cefiderocol showed 89.3% EA (95% CI: 81.9%-93.9%) (not significantly different from 90.0%, Student t-test) with a bias of -3.9% and a CA of 94.2% (95% CI: 87.7%-97.3%). CONCLUSIONS: UMIC® Cefiderocol is a valid method for the determination of cefiderocol MICs even if higher than expected discrepancies were observed with NDM-producing Enterobacterales, which presented in most cases MIC values close to the breakpoint.

Molecular surveillance reveals the emergence and dissemination of NDM-5-producing Escherichia coli high-risk clones in Germany, 2013 to 2019.

BackgroundCarbapenemase-producing Enterobacterales (CPE) are rapidly increasing worldwide, also in Europe. Although prevalence of CPE in Germany is comparatively low, the National Reference Centre for Multidrug-resistant Gram-negative Bacteria noted annually increasing numbers of NDM-5-producing Escherichia coli isolates.AimAs part of our ongoing surveillance programme, we characterised NDM-5-producing E. coli isolates received between 2013 and 2019 using whole genome sequencing (WGS).MethodsFrom 329 identified NDM-5-producing E. coli, 224 isolates from known geographical locations were subjected to Illumina WGS. Analyses of 222 sequenced isolates included multilocus sequence typing (MLST), core genome (cg)MLST and single-nucleotide polymorphism (SNP)-based analyses.ResultsResults of cgMLST revealed genetically distinct clusters for many of the 43 detected sequence types (ST), of which ST167, ST410, ST405 and ST361 predominated. The SNP-based phylogenetic analyses combined with geographical information identified sporadic cases of nosocomial transmission on a small spatial scale. However, we identified large clusters corresponding to clonal dissemination of ST167, ST410, ST405 and ST361 strains in consecutive years in different regions in Germany.ConclusionOccurrence of NDM-5-producing E. coli rose in Germany, which was to a large extent due to the increased prevalence of isolates belonging to the international high-risk clones ST167, ST410, ST405 and ST361. Of particular concern is the supra-regional dissemination of these epidemic clones. Available information suggest community spread of NDM-5-producing E. coli in Germany, highlighting the importance of epidemiological investigation and an integrated surveillance system in the One Health framework.

Susceptibility of Multidrug-Resistant Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa from Germany to Ceftolozane-Tazobactam, Ceftazidime-Avibactam, and Imipenem-Relebactam.

This cross-sectional in-vitro resistance surveillance study involving 10 medical laboratories was conducted in 2018. Each study site was asked to collect 30 consecutive nonduplicate isolates per species from hospitalized patients with documented infections. Minimum inhibitory concentrations were determined at a central laboratory. European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints were used for interpretation. A total of 860 isolates were collected, including 298 Escherichia coli, 268 Klebsiella pneumoniae, and 294 Pseudomonas aeruginosa. Fifty (16.8%) E. coli and 63 (23.5%) K. pneumoniae isolates were found to be resistant to third-generation cephalosporins. Resistance to carbapenems (imipenem and/or meropenem) was identified in 5 (1.9%) K. pneumoniae and 64 (21.8%) P. aeruginosa, but not in E. coli. Thirty-three (11.2%) P. aeruginosa isolates were resistant to both carbapenems and 30 (10.2%) P. aeruginosa showed resistance to ≥3 antimicrobials/antimicrobial groups (among piperacillin-tazobactam, ceftazidime, tobramycin, carbapenems, and fluoroquinolones). The susceptibility rates of these multidrug-resistant (MDR) phenotypes to ceftolozane-tazobactam, ceftazidime-avibactam, and imipenem-relebactam were 70-100%, with the exception of carbapenem-resistant K. pneumoniae. Only two K. pneumoniae and four P. aeruginosa isolates were resistant to all three beta-lactam/beta-lactamase-inhibitor combinations. However, this favorable result should be viewed in light of the relatively low prevalence of MDR organisms that require these agents in Germany.

Increased zinc levels facilitate phenotypic detection of ceftazidime-avibactam resistance in metallo-ß-lactamase-producing Gram-negative bacteria.

Ceftazidime-avibactam is one of the last resort antimicrobial agents for the treatment of carbapenem-resistant, Gram-negative bacteria. Metallo-ß-lactamase-producing bacteria are considered to be ceftazidime-avibactam resistant. Here, we evaluated a semi-automated antimicrobial susceptibility testing system regarding its capability to detect phenotypic ceftazidime-avibactam resistance in 176 carbapenem-resistant, metallo-ß-lactamase-producing Enterobacterales and Pseudomonas aeruginosa isolates. Nine clinical isolates displayed ceftazidime-avibactam susceptibility in the semi-automated system and six of these isolates were susceptible by broth microdilution, too. In all nine isolates, metallo-ß-lactamase-mediated hydrolytic activity was demonstrated with the EDTA-modified carbapenemase inactivation method. As zinc is known to be an important co-factor for metallo-ß-lactamase activity, test media of the semi-automated antimicrobial susceptibility testing system and broth microdilution were supplemented with zinc. Thereby, the detection of phenotypic resistance was improved in the semi-automated system and in broth microdilution. Currently, ceftazidime-avibactam is not approved as treatment option for infections by metallo-ß-lactamase-producing, Gram-negative bacteria. In infections caused by carbapenem-resistant Gram-negatives, we therefore recommend to rule out the presence of metallo-ß-lactamases with additional methods before initiating ceftazidime-avibactam treatment.

Shewanella algae bacteraemia in a patient with a chronic ulcer after contact with seawater on vacation in Turkey: A case report from a German maximum-care hospital.

After seawater baths in Antalya, Turkey, a 55-year-old man suffered from Shewanella algae bacteraemia. Imported/travel-related S. algae infections should be kept in mind, also in usually rather cold geographical areas, as patterns of seawater-associated bacilli infections might change due to warming of seawater caused by climate change.

Detection of OXA-181-producing Pseudomonas aeruginosa in Germany.

OBJECTIVES: To report the detection of the class D carbapenemase OXA-181 in an MDR clinical Pseudomonas aeruginosa isolate in Germany. METHODS: Carbapenemase detection was performed by using several phenotypic tests such as the modified Hodge test, a combined disc test with boronic acid, EDTA or cloxacillin, a lysate-based inhibition assays and by PCR for common and rare carbapenemase genes. Antibiotic susceptibilities were determined by broth microdilution. The genetic environment of blaOXA-181 in the clinical P. aeruginosa isolate was characterised by Illumina and MinION sequencing. RESULTS: An multidrug-resistant P. aeruginosa was isolated from a tracheal swab in 2019 and was sent to the German National Reference Centre for multidrug-resistant Gram-negative bacteria for carbapenemase detection. Several phenotypic tests indicated the presence of a carbapenemase which was not inhibited by EDTA nor by boronic acid. PCRs for common and rare carbapenemase genes revealed the presence of a blaOXA-181 gene. WGS data confirmed that the gene was located on the chromosome as part of a Tn2013 transposon. The genetic organisation of blaOXA-181 has already been described in a P. aeruginosa isolate from England, but both isolates differed significantly in their sequence types (ST111/ST235). Analysis of the genetic environment of the blaOXA-181 gene also revealed high homology to a plasmid from a Klebsiella pneumoniae isolate. CONCLUSIONS: To our knowledge, this is the first report of blaOXA-181 in a clinical P. aeruginosa isolate in Germany which emphasises the ongoing spread of yet unusual carbapenemases among different Gram-negative species and therefore complicating their detection in routine laboratories.

Combined Clinical, Epidemiological, and Genome-Based Analysis Identified a Nationwide Outbreak of Burkholderia cepacia Complex Infections Caused by Contaminated Mouthwash Solutions.

Background: In September 2018, Burkholderia cepacia complex (BCC) infections in 3 patients associated with exposure to a mouthwash solution (MWS) were reported to the Robert Koch Institute (RKI). As the product was still on the market and the scale of the outbreak was unclear, a nation-wide investigation was initiated. Methods: We aimed to investigate BCC infections/colonizations associated with MWS. Hospitals, laboratories, and public health services were informed that BCC isolates should be sent to the RKI. These isolates were typed by pulsed-field gel electrophoresis (PFGE) and whole-genome sequencing (WGS) including development of an ad hoc core genome MLST (cgMLST) scheme. Results: In total, 36 patients from 6 hospitals met the case definition, the last patient in November 2018. Twenty-nine isolates from 26 of these patients were available for typing. WGS analysis revealed 2 distinct cgMLST clusters. Cluster 1 (Burkholderia arboris) contained isolates from patients and MWS obtained from 4 hospitals and isolates provided by the manufacturer. Patient and MWS isolates from another hospital were assigned to cluster 2 (B. cepacia). Conclusions: The combined clinical, epidemiological, and microbiological investigation, including whole-genome analysis, allowed for uncovering a supraregional BCC outbreak in health care settings. Strains of B. arboris and B. cepacia were identified as contaminating species of MWS bottles and subsequent colonization and putative infection of patients in several hospitals. Despite a recall of the product by the manufacturer in August 2018, the outbreak lasted until December 2018. Reporting of contaminated medical products and recalls should be optimized to protect patients.

Effect of sigma E on carbapenem resistance in OXA-48-producing Klebsiella pneumoniae.

OBJECTIVES: Resistance levels of Gram-negative bacteria producing OXA-48 carbapenemase can vary greatly and some of them can even be categorized as susceptible to imipenem and meropenem according to EUCAST breakpoints. This study aimed to reveal resistance mechanisms leading to varying levels of resistance to carbapenems in Klebsiella pneumoniae with blaOXA-48 submitted to the German National Reference Centre for MDR Gram-negative bacteria. METHODS: Meropenem-susceptible clinical blaOXA-48-bearing K. pneumoniae isolates were put under gradually increasing selective pressure of meropenem. Clinical isolates and spontaneous meropenem-resistant mutants were whole-genome sequenced with Illumina and Oxford Nanopore Technology. Identified mutations apart from porin mutations were genetically constructed in the original clinical isolates using CRISPR/Cas. Clinical isolates and mutants were analysed for MICs, growth rates and expression of porins on mRNA and protein levels. RESULTS: Mutations associated with meropenem resistance were predominantly found in ompK36, but in some cases ompK36 was unaffected. In two mutants, ISs within the rpoE (sigma factor E; σE) operon were detected, directly in or upstream of rseA. These IS1R elements were then inserted into the same position of the susceptible clinical isolates using CRISPR/Cas. CRISPR-rseA-rseB-rseC mutants showed higher resistance levels to carbapenems and cephalosporins, reduced growth rates and reduced expression of major porins OmpK36 and OmpK35 in quantitative RT-PCR and SDS-PAGE. CONCLUSIONS: Enhanced synthesis of σE leads to increased resistance to cephalosporins and carbapenems in clinical K. pneumoniae isolates. This effect could be based upon remodelling of expression patterns of outer membrane proteins. The up-regulated σE stress response also leads to a significant reduction in growth rates.

Characterization of GMB-1, a novel metallo-ß-lactamase (MBL) found in three different Enterobacterales species.

OBJECTIVES: To identify novel carbapenem resistance mechanisms and their potential to spread among clinical isolates. METHODS: Four clinical isolates of Citrobacter freundii, Serratia marcescens and Raoultella planticola (n = 2) from one hospital in Central Germany were sent to the German National Reference Centre for Multidrug-resistant Gram-negative Bacteria for carbapenemase detection. Phenotypic tests indicated the presence of a metallo-ß-lactamase (MBL), but PCR for various MBL genes could not identify any. Using WGS data, a putative bla gene was identified. Its carbapenemase activity was verified by heterologous expression in an Escherichia coli cloning strain, with subsequent MIC determination by broth microdilution, as well as by in vitro hydrolysis assays using purified enzyme. RESULTS: WGS indicated the presence of a putative ß-lactamase with 48% amino acid identity to the subclass B1 MBL SPM-1. MIC studies confirmed that the novel enzyme formed a functional MBL, which was therefore designated as GMB-1 (German MBL). In vitro hydrolysis assays showed a lack of activity not only against aztreonam but also against ertapenem. WGS revealed that in all three species the blaGMB-1 gene was located on the chromosome as part of a genetic island with multiple ISs. CONCLUSIONS: The finding of GMB-1 once again shows that novel carbapenemases continue to emerge and make their way into clinically relevant species. The occurrence of GMB-1 in three different species demonstrates the extraordinary mobility of such genetic islands and their potential to spread carbapenemase genes into diverse genetic environments.

Geographical differences of carbapenem non-susceptible Enterobacterales and Acinetobacter spp. in Germany from 2017 to 2019.

BACKGROUND: Since May 2016, infection and colonisation with carbapenem non-susceptible Acinetobacter spp. (CRA) and Enterobacterales (CRE) have to be notified to health authorities in Germany. The aim of our study was to assess the epidemiology of CRA and CRE from 2017 to 2019 in Germany, to identify risk groups and to determine geographical differences of CRA and CRE notifications. METHODS: Cases were notified from laboratories to local public health authorities and forwarded to state and national level. Non-susceptibility was defined as intermediate or resistant to ertapenem, imipenem, or meropenem excluding intrinsic bacterial resistance or the detection of a carbapenemase gene. We analysed CRA and CRE notifications from 2017, 2018 and 2019 per 100,000 inhabitants (notification incidence), regarding their demographic, clinical and laboratory information. The effect of regional hospital-density on CRA and CRE notification incidence was estimated using negative binomial regression. RESULTS: From 2017 to 2019, 2278 CRA and 12,282 CRE cases were notified in Germany. CRA and CRE cases did not differ regarding demographic and clinical information, e.g. proportion infected. The notification incidence of CRA declined slightly from 0.95 in 2017 to 0.86 in 2019, whereas CRE increased from 4.23 in 2017 to 5.72 in 2019. The highest CRA and CRE notification incidences were found in the age groups above 70 years. Infants below 1 year showed a high CRE notification incidence, too. Notification incidences varied between 0.10 and 2.86 for CRA and between 1.49 and 9.99 for CRE by federal state. The notification incidence of CRA and CRE cases increased with each additional hospital per district. CONCLUSION: The notification incidence of CRA and CRE varied geographically and was correlated with the number of hospitals.The results support the assumption that hospitals are the main driver for higher CRE and CRA incidence. Preventive strategies and early control measures should target older age groups and newborns and areas with a high incidence.

Increase in NDM-1 and NDM-1/OXA-48-producing Klebsiella pneumoniae in Germany associated with the war in Ukraine, 2022.

In 2022, German surveillance systems observed rapidly increasing numbers of NDM-1- and NDM-1/OXA-48-producing Klebsiella pneumoniae, which may in part reflect recurring pre-pandemic trends. Among these cases, however, a presence in Ukraine before diagnosis was frequently reported. Whole genome sequencing of 200 isolates showed a high prevalence of sequence types ST147, ST307, ST395 and ST23, including clusters corresponding to clonal dissemination and suggesting onward transmission in Germany. Screening and isolation of patients from Ukraine may help avoid onward transmission.

Evaluation of the rCIM for carbapenemase detection in Enterobacterales and Pseudomonas aeruginosa and description of the TSBrCIM, an optimized variant.

OBJECTIVES: The rapid Carbapenem Inactivation Method (rCIM) was evaluated with a strain collection of 164 and 69 carbapenem-resistant Enterobacterales and Pseudomonas aeruginosa, respectively, that produced various carbapenemases. For an improved carbapenemase detection in Enterobacterales, an optimized variant of the rCIM named TSBrCIM was developed. METHODS: Bacterial isolates were incubated with two meropenem disks in distilled water (rCIM) or tryptic soy broth (TSBrCIM). After centrifugation, the supernatant was incubated with a susceptible E. coli indicator strain in tryptic soy broth. Growth of the indicator strain implied carbapenemase activity in the test strain. RESULTS: The rCIM detected 100/113 carbapenemase-producing Enterobacterales, resulting in a sensitivity of 88.5% and a specificity of 94.1%. For P. aeruginosa, sensitivity and specificity were 96.0% and 100%, respectively. The TSBrCIM was able to detect 105/113 carbapenemase-producing Enterobacterales, resulting in a sensitivity of 92.9% and a specificity of 96.1%. CONCLUSION: This study shows that the TSBrCIM can be valuable tool for detection of carbapenemases in Enterobacterales in the clinical laboratory, while the rCIM showed the best results for carbapenemase detection in P. aeruginosa.