Antibiotic and antimicrobial resistance

Antimicrobial resistance is highly correlated with inappropriate antimicrobial use. Urinary tract infections (UTIs) are the main infections treated with antibiotics in the population ≥ 70 years.

We aimed to investigate antibiotic prescribing patterns for UTIs treatment among older people in Denmark and resistance trends to assess impact of antibiotic stewardship interventions and quality improvement strategies.

This national register-based surveillance study included people ≥ 70 years in Danish primary healthcare and assessed consumption of pivmecillinam, trimethoprim, nitrofurantoin and sulfamethizole from 1999 to 2023 and resistance levels from 2018 to 2023. Consumption data were obtained from the Register of Medicinal Product Statistics and resistance data from the Danish Microbiology Database. A review of quality improvement strategies from 2005 to 2020 was conducted to provide context for the study.

The highest level of antibiotic consumption for UTIs in older people was in 2014 (447 prescriptions/1,000 people ≥ 70 years) and gradually decreased by 28.4% in 2023. Resistance to pivmecillinam, trimethoprim, sulfamethizole and nitrofurantoin in Escherichia coli and Klebsiella pneumoniae decreased significantly from 2018 to 2023, alongside the decline in antibiotic consumption. Focus on antibiotic stewardship was intensified after 2013, with several quality improvement initiatives and updated treatment guidelines aiming at improving diagnosis and antibiotic treatment.

Antibiotic consumption for UTIs in people ≥ 70 years decreased notably, accompanied by a decrease in resistance levels, reflecting a positive impact of antibiotic stewardship programmes to improve diagnosis and treatment. However, a growing older population could place a strain on healthcare resources in the future.

Dual penicillin- and ciprofloxacin-resistant Neisseria meningitidis causing invasive meningococcal disease (IMD) have recently emerged in association with sequence type (ST) 3587, harbouring ROB-1 β-lactamase (bla ROB-1) and a mutated DNA gyrase (gyrA). These strains pose a threat to current antimicrobial treatment and prophylaxis.

We aimed to characterise the first dual-resistant N. meningitidis ST-3587 isolates harbouring bla ROB-1 and a mutated gyrA identified in Spain.

Three N. meningitidis isolates encoding bla ROB-1 were identified in 2024. They were characterised by whole genome sequencing to determine capsular genogroups, ST and genetic antimicrobial resistance markers. Dated phylogenetic analysis was performed alongside global ST-3587 strains.

The three bla ROB-1-encoding isolates belonged to ST-3587, genogroup Y, harboured a T91I mutation in gyrA and showed resistance to penicillin and ciprofloxacin. These isolates were obtained from urethral, oropharyngeal and blood samples, each from a different patient. According to the dated phylogenetic analysis of ST-3587 and the presence of bla ROB-1, two clades were defined: clade I and clade II. Within clade II, subclade II.I was identified, comprising isolates which, in addition to bla ROB-1, carried the T91I mutation in gyrA. This subclade included the three Spanish isolates, which exhibited close genetic relatedness.

This study documents the emergence of N. meningitidis ST-3587 with dual resistance in Europe, including a documented urogenital infection by this lineage. Continued surveillance of antimicrobial resistance in N. meningitidis, including non-invasive cases, is crucial for timely public health responses and effective IMD prevention strategies.

Carbapenemase-producing Enterobacterales (CPE) cause infections, particularly nosocomially, with limited treatment options. NDM-1-producing Klebsiella pneumoniae cases have substantially increased since 2022, associated with the Ukraine war.

We aimed to investigate transmission patterns using Germany’s Integrated Genomic Surveillance (IGS), combining notifications and sequence data.

We selected NDM-1-producing K. pneumoniae cases, confirmed by isolates between 1 January 2022 and 28 February 2023. Isolates were Illumina whole genome-sequenced and linked to notifications. Clusters were defined as ≤ 12 allelic differences in core genome-wide single nucleotide variant-based genotyping. Cluster categories were: ‘no exposure abroad’, ‘exposure in Ukraine’ or ‘other exposure abroad’ if ≥ one case stayed in Ukraine or elsewhere. Follow-up of 13 clusters examined further exposure information.

Among 424 cases of most frequent sequence types, 326 (77%) belonged to 61 clusters. Seventeen (28%) clusters were associated with no exposure abroad, 33 (54%) with exposure in Ukraine, seven (11%) with other exposure abroad, and four (7%) had insufficient data. Cases in clusters with exposure in Ukraine were more dispersed, younger, and more often wound-infected than in other exposure location categories (p < 0.01). Cluster follow-up revealed one cluster with all cases from Ukraine or Russia, another with nosocomial transmission following case importation, and a third with all cases from one German hospital without exposure abroad.

Most cases were in clusters, suggesting preventable chains of transmission. Three patterns emerged: transmission abroad, transmission in German hospitals from imported cases or local outbreaks. IGS can identify where transmission could be interrupted. International cooperation needs strengthening to prevent CPE spread.

To enhance antibiotic stewardship and effectively address antimicrobial resistance (AMR), better understanding of subnational antibiotic consumption patterns is essential.

We aimed to assess antibiotic consumption in Germany using data from 2022 and integrated from two surveillance systems, focusing on regional differences by examining non-university acute care hospitals.

We used pharmacy dispensing data from 525 regional or local hospitals and 35 university hospitals, covering 46.5 million patient days (PD), nearly half of all occupied bed days nationwide, to calculate antibiotic use densities (AUD) for systemic antibiotics, expressed as World Health Organization (WHO) ATC/DDD (Anatomical Therapeutic Chemical/Defined Daily Dose) per 100 patient days (DDD/100 PD). The analysis primarily focused on consumption patterns in non-university hospitals, assessing key antibiotic groups through mixed-effects regression. For sensitivity analyses, we employed hospital-adapted daily dose definitions.

Pooled AUD for participating non-university hospitals was 51.8 DDD/100 PD, with aminopenicillins/beta-lactamase inhibitors being the most prescribed group. Regression analyses, adjusted for hospital size and ward type/admitting specialty, indicated notable regional variation. We identified statistically significant differences in antibiotic consumption, particularly for beta-lactam antibiotics, fluoroquinolones and tetracyclines. For example, several regions exhibited up to 1.4-fold higher use of first- and second-generation cephalosporins compared with the western reference region.

This study highlights substantial regional variation in antibiotic use in German acute care hospitals, underlining the importance of further investigation into influencing factors such as regional guidelines and resistance rates. The methodological approach applied here may serve as a model for other countries interested in analysing regional differences in antibiotic consumption.

Fifteen- and 20-valent pneumococcal conjugate vaccines (PCVs) offer broader protection against invasive pneumococcal disease (IPD) than PCV13. Adopting these vaccines may result in decreasing IPD incidence, antibiotic use and antimicrobial resistance (AMR) rates. If the additional serotypes in PCV15 and PCV20 are associated with AMR, AMR rate reduction could be greater than expected from reduced antibiotic consumption alone.

This retrospective analysis assessed the association between AMR and non-PCV13 serotypes in PCV15 and PCV20.

Laboratory-based surveillance data on 8,123 IPD isolates were obtained retrospectively from the Belgian Reference Centre for invasive Streptococcus pneumoniae. Isolates (n = 8,088) were serotyped and tested for AMR. Associations between vaccine serotype groups and AMR were evaluated by multinomial logistic regression. Where associations varied with patients’ age, ranges of odds ratios (ORs) are presented.

PCV15-non-PCV13 and PCV20-non-PCV13 serotypes accounted for 7.4% (n = 597) and 37% (n = 2,992) of IPD isolates respectively. Of non-PCV20 serotypes, 24% (508/2,125) were penicillin resistant. Compared with non-PCV20 serotypes, PCV15-non-PCV13 serotypes were more often associated with erythromycin (ORs: 3.59–9.43) and tetracycline (OR: 2.00) resistance, and with trimethoprim/sulfamethoxazole (OR: 0.11) susceptibility. PCV20-non-PCV15 serotypes were more often associated with amoxicillin (OR: 9.45) and cefotaxime (ORs: 5.06–82.38) resistance, and with erythromycin (ORs: 0.13–0.18), tetracycline (OR: 0.71) and penicillin (ORs: 0.05–0.46) susceptibility.

PCV20 may lead to a larger decrease in overall IPD incidence than PCV15. Although the PCV20 vaccination impact on AMR may be limited, some resistant or difficult to treat infections could be avoided. Serotype replacement might lead to infections with low level penicillin resistance increasing, but most of these should remain treatable.

Mandatory reporting of healthcare-associated infections (HCAI) in England is conducted locally by acute hospital groups and can be a large burden on healthcare staff.

We aimed to determine the case ascertainment of a potential centrally-implemented, automated HCAI surveillance system in England using preexisting data feeds at the UK Health Security Agency.

We compared monthly case numbers submitted between 1 April 2016 and 31 March 2023 by acute hospital groups (locally-implemented surveillance) to routinely-collected laboratory and hospital encounter records (centrally-implemented surveillance) for all infections under mandatory surveillance in England. Since laboratories can serve multiple hospitals, we compared several methods of assigning laboratory-confirmed cases to hospital groups.

Locally-implemented vs centrally-implemented surveillance identified: meticillin-resistant Staphylococcus aureus bacteraemias 5,453 vs 5,859 (ratio 1.07), meticillin-susceptible S. aureus bacteraemias 84,680 vs 83,326 (0.98), Escherichia coli bacteraemias 281,100 vs 275,133 (0.98), Klebsiella species bacteraemias 65,877 vs 67,301 (1.02), Pseudomonas aeruginosa bacteraemias 25,862 vs 25,715 (0.99), Clostridioides difficile infections (CDI) 94,054 v 90,942 (0. 97) respectively. Assigning hospital groups by linking laboratory records to hospital encounters produced lower monthly mean absolute difference (MAD) vs locally-implemented surveillance than using laboratory records alone. MAD was 0.65 cases/month for bacteraemias, 2.99 for CDI; differences occurred in both directions. MAD decreased over time for bacteraemias but increased from April 2021 onwards for CDI.

Centrally-implemented surveillance could be feasible for bacteraemias in England due to comparable case numbers with local surveillance. However, more research is needed around understanding and managing data quality of automated feeds, particularly for CDI.

Data for healthcare-associated infections (HAI) and antibiotic use in long-term care facilities (LTCF) in Switzerland are lacking but are necessary to take actions.

We aimed to estimate HAI prevalence and antibiotic use and to record existing structure and process indicators in the area of infection prevention/antibiotic use in Swiss LTCF.

We invited all Swiss LTCF for this PPS in September 2024 using the adapted Healthcare-Associated Infections in European Long-Term Care Facilities (HALT)-4 protocol. The proportion of residents with HAI and systemic antibiotic treatment was calculated for a representative sample, stratified by language region and size. We assessed resident-level and institutional risk factors for HAI in all participating institutions, using random-effects logistic regression.

We included 94 LTCF (7,244 residents), whereof 49 LTCFs (3,375 residents) belonged to the representative sample. Median age of residents in the representative sample was 87 years (range: 36–107) and 2,334 (69.2%) were female. Prevalence of HAI was 2.2% (95% confidence interval (CI): 1.7–2.7); 2.7% (95% CI: 2.2–3.3) were receiving antibiotic treatment, with highest use in LTCF in French-speaking cantons (5.9%; 95% CI: 4.2–7.5). Urinary tract (46%) and respiratory infections (20%) were most common, aminopenicillins (26%) and nitrofurantoin (19%) the most commonly used antimicrobials. The strongest independent risk factor for HAI was presence of urinary catheters (adjusted odds ratio = 2.65; 95% CI: 1.71–4.11).

Prevalence of HAI and antibiotic use in Swiss LTCFs were comparable to the European average from 2023/24. There are regional differences in antibiotic consumption. Urinary catheterisation, potentially modifiable, was the most important risk factor for HAI.