Susceptibility of ceftobiprole against Gram-positive and Gram-negative clinical isolates from 2019 from different European territories.

OBJECTIVES: Ceftobiprole is approved for use in treatment of hospital-associated and community-acquired pneumonia in 16 different European countries and is currently undergoing clinical trials in the United States. METHODS: Isolates were collected from hospital laboratories from 16 European countries during 2019 as part of an ongoing post-marketing surveillance study. MICs were determined using EUCAST broth microdilution methodology and interpreted using 2020 EUCAST breakpoints. RESULTS: Ceftobiprole was active (MIC, ≤2 mg/L) against 100% and 99.3% of methicillin-susceptible Staphylococcus aureus and MRSA isolates collected in 2019. Against Streptococcus pneumoniae, ceftobiprole was active (MIC, ≤0.5 mg/L) against 98.4% of isolates. Overall, 77.4% of Enterobacterales were susceptible though isolate numbers in certain countries were notably low. In addition, based on non-species-related PK/PD breakpoints, 69.7% of Pseudomonas aeruginosa isolates were susceptible to ceftobiprole. Analysis of data by geographical regions showed that susceptibility to ceftobiprole by region or country was not significantly varied though MRSA, S. pneumoniae, Enterobacterales and P. aeruginosa. Isolates from Italy had lower susceptibilities to ceftobiprole: 98% of MRSA, 94% of S. pneumoniae and 61% of Enterobacterales isolates were susceptible to ceftobiprole. CONCLUSION: The data for ceftobiprole for isolates from 2019 are encouragingly very similar to studies performed on isolates from earlier years showing that susceptibility to ceftobiprole has not changed and, importantly, that resistance emergence remains low throughout Europe.

In vitro activity of ceftobiprole and comparator antibiotics against contemporary European isolates (2016-19).

Objectives: To evaluate the susceptibility to ceftobiprole of clinical bacterial isolates obtained from hospitalized patients in Europe. Methods: A total of 20 000 non-duplicate bacterial isolates were collected in 2016-19 from patients with documented infections at medical centres located in 17 countries in Europe. Bacterial identification was confirmed and susceptibility to ceftobiprole and comparator agents was tested using the EUCAST broth microdilution methodology and interpretive criteria by a central microbiology laboratory. Results: Of the 20 000 isolates, 10 007 (50.0%) were Gram-positive and 9993 (50.0%) were Gram-negative. The most common species was Staphylococcus aureus (35.0%), followed by Streptococcus pneumoniae (15.0%), Klebsiella pneumoniae (11.1%), Pseudomonas aeruginosa (11.0%), Escherichia coli (9.7%) and Haemophilus influenzae (3.0%). Overall, 99.7% (6981/7000) of S. aureus, including 99.5% (3483/3502) of MRSA, 97.8% (2941/3007) of S. pneumoniae, 100% (605/605) of H. influenzae and 76.3% (5492/7197) of Enterobacterales isolates were susceptible to ceftobiprole. Susceptibility to ceftobiprole was higher for isolates from northern and western Europe as compared with eastern and southern Europe. Conclusions: Ceftobiprole continues to exhibit potent and broad-spectrum activity against Gram-positive and Gram-negative clinical isolates from Europe, and as expected, with a slight north-to-south and west-to-east susceptibility gradient.

Toxoplasma gondii transmembrane microneme proteins and their modular design.

Host cell invasion by the Apicomplexa critically relies on regulated secretion of transmembrane micronemal proteins (TM-MICs). Toxoplasma gondii possesses functionally non-redundant MIC complexes that participate in gliding motility, host cell attachment, moving junction formation, rhoptry secretion and invasion. The TM-MICs are released onto the parasite's surface as complexes capable of interacting with host cell receptors. Additionally, TgMIC2 simultaneously connects to the actomyosin system via binding to aldolase. During invasion these adhesive complexes are shed from the surface notably via intramembrane cleavage of the TM-MICs by a rhomboid protease. Some TM-MICs act as escorters and assure trafficking of the complexes to the micronemes. We have investigated the properties of TgMIC6, TgMIC8, TgMIC8.2, TgAMA1 and the new micronemal protein TgMIC16 with respect to interaction with aldolase, susceptibility to rhomboid cleavage and presence of trafficking signals. We conclude that several TM-MICs lack targeting information within their C-terminal domains, indicating that trafficking depends on yet unidentified proteins interacting with their ectodomains. Most TM-MICs serve as substrates for a rhomboid protease and some of them are able to bind to aldolase. We also show that the residues responsible for binding to aldolase are essential for TgAMA1 but dispensable for TgMIC6 function during invasion.

Surveillance of ceftobiprole against Gram-positive and Gram-negative clinical isolates from 2018 from different European territories.

OBJECTIVES: Ceftobiprole is approved for the treatment of hospital-acquired and community-acquired pneumonia in 17 different European countries and is currently undergoing clinical trials in the USA. METHODS: In this study, isolates were collected from hospital laboratories from 15 European countries during 2018 as part of an ongoing post-marketing surveillance study. Minimum inhibitory concentrations (MICs) were determined using European Committee on Antimicrobial Susceptibility Testing (EUCAST) broth microdilution methodology and were interpreted using 2019 EUCAST breakpoints. RESULTS: Ceftobiprole was active (MIC, ≤2 mg/L) against 100% and 98.9% of methicillin-susceptible Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) from 2018, respectively. Only six MRSA isolates (1.1%) were resistant to ceftobiprole and originated from four countries. Against Streptococcus pneumoniae, ceftobiprole was active (MIC, ≤0.5 mg/L) against 98.7% of isolates. Overall, 75.6% of Enterobacterales were susceptible, although isolate numbers in certain countries were notably low. In addition, based on non-species-related pharmacokinetic/pharmacodynamic breakpoints, 63.2% of Pseudomonas aeruginosa isolates were susceptible to ceftobiprole. CONCLUSION: Data for ceftobiprole for isolates from 2018 are very similar to studies performed on isolates from earlier years, showing that susceptibility to ceftobiprole has remained high.

Small variant surface antigens and Plasmodium evasion of immunity.

Antigenic variation at the Plasmodium-infected erythrocyte surface plays a critical role in malaria disease severity and host immune evasion. Our current understanding of the role of Plasmodium variant surface antigens in antigenic variation and immune evasion is largely limited to the extensive work carried out on the Plasmodium falciparum var gene family. Although homologues of var genes are not present in other malaria species, small variant gene families comprising the rif and stevor genes in P. falciparum and the pir genes in Plasmodium vivax, Plasmodium knowlesi and the rodent malaria Plasmodium chabaudi, Plasmodium berghei and Plasmodium yoelii also show features suggesting a role in antigenic variation and immune evasion. In this article, we highlight our current understanding of these variant antigens and provide insights on the mechanisms developed by malaria parasites to effectively avoid the host immune response and establish chronic infection.