eThe in vitro activity of the novel antimicrobial peptide dendrimer G3KL was evaluated against 32 Acinetobacter baumannii (including 10 OXA-23, 7 OXA-24, and 11 OXA-58 carbapenemase producers) and 35 Pseudomonas aeruginosa (including 18 VIM and 3 IMP carbapenemase producers) strains and compared to the activities of standard antibiotics. Overall, both species collections showed MIC 50/90 values of 8/8 g/ml and minimum bactericidal concentrations at which 50% or 90% of strains tested are killed (MBC 50/90 ) of 8/8 g/ml. G3KL is a promising molecule with antibacterial activity against multidrug-resistant and extensively drug-resistant A. baumannii and P. aeruginosa isolates. The spread of Acinetobacter baumannii and Pseudomonas aeruginosa isolates that are resistant to carbapenem antibiotics due to the production of carbapenemases represents a serious threat (1). These strains are usually multidrug-resistant (MDR) due to the coexpression of mechanisms involving other classes of antibiotics, thus drastically limiting our therapeutic armamentarium (2-4). In particular, extensively drug-resistant (XDR) isolates are commonly detected worldwide (5), whereas the prevalence of pandrug-resistant (PDR) isolates is increasing worryingly in several countries (6-8). Therefore, novel antimicrobial strategies need to be rapidly developed.Recently, there has been a rising interest in evaluating naturally occurring or synthetic antimicrobial peptides (AMPs) with activity against prokaryotic membranes. This attention is due to their wide spectrum of activity against both Gram-positive and Gramnegative species, potent bactericidal activity, and ability to bypass common mechanisms of resistance that affect standard antibiotics (9, 10). However, several reasons have so far limited the clinical implementation of AMPs: (i) high susceptibility to degradation by endogenous and microbial proteases; (ii) toxicity due to the high concentration necessary to inhibit bacteria; and (iii) short half-life because of high protein binding (11). Several authors have modified AMPs to obtain proteolytically resistant versions, mostly by sequence variations and the use of D-amino acids (12-15). However, redesigning the peptide chain topology, in particular by introducing multiple branching points to obtain synthetic AMP dendrimers (AMPDs), seems a promising solution to overcome all of the the aforementioned problems (16-18).G3KL is a novel AMP dendrimer (AMPD) developed at the Department of Chemistry and Biochemistry of the University of Bern (Switzerland) by sequence optimization of an initial hit compound identified by screening a combinatorial library of dendrimers using a tailored high-throughput screening assay and presumed to act as a membrane-disrupting agent (19)(20)(21)(22). Its activity requires a dendritic topology and only natural lysine and leucine residues alternating in the branches (Fig. 1). This novel AMPD has demonstrated in vitro activity against several Gram-negative strains, low toxicity to human red blood cells (minimal hemolytic ...

f Stool samples from 38 travelers returning from India were screened for extended-spectrum cephalosporin-and carbapenemresistant Enterobacteriaceae implementing standard selective plates. Twenty-six (76.3%) people were colonized with CTX-M or DHA producers, but none of the strains was colistin resistant and/or mcr-1 positive. Nevertheless, using overnight enrichment and CHROMagar Orientation plates supplemented with colistin, four people (10.5%) were found to be colonized with colistinresistant Escherichia coli. One cephalosporin-susceptible sequence type 10 (ST10) strain carried a 4,211-bp ISApl1-mcr-1-ISApl1 element in an IncHI2 plasmid backbone.

Antibiotic resistance in Ureaplasma urealyticum/Ureaplasma parvum and Mycoplasma hominis is an issue of increasing importance. However, data regarding the susceptibility and, more importantly, the clonality of these organisms are limited. We analyzed 140 genital samples obtained in Bern, Switzerland, in 2014. Identification and antimicrobial susceptibility tests were performed by using the Mycoplasma IST 2 kit and sequencing of 16S rRNA genes. MICs for ciprofloxacin and azithromycin were obtained in broth microdilution assays. Clonality was analyzed with PCR-based subtyping and multilocus sequence typing (MLST), whereas quinolone resistance and macrolide resistance were studied by sequencing gyrA, gyrB, parC, and parE genes, as well as 23S rRNA genes and genes encoding L4/L22 ribosomal proteins. A total of 103 samples were confirmed as positive for U. urealyticum/U. parvum, whereas 21 were positive for both U. urealyticum/U. parvum and M. hominis. According to the IST 2 kit, the rates of nonsusceptibility were highest for ciprofloxacin (19.4%) and ofloxacin (9.7%), whereas low rates were observed for clarithromycin (4.9%), erythromycin (1.9%), and azithromycin (1%). However, inconsistent results between microdilution and IST 2 kit assays were recorded. Various sequence types (STs) observed previously in China (ST1, ST2, ST4, ST9, ST22, and ST47), as well as eight novel lineages, were detected. Only some quinolone-resistant isolates had amino acid substitutions in ParC (Ser83Leu in U. parvum of serovar 6) and ParE (Val417Thr in U. parvum of serovar 1 and the novel Thr417Val substitution in U. urealyticum). Isolates with mutations in 23S rRNA or substitutions in L4/L22 were not detected. This is the first study analyzing the susceptibility of U. urealyticum/U. parvum isolates in Switzerland and the clonality outside China. Resistance rates were low compared to those in other countries. We hypothesize that some hyperepidemic STs spread worldwide via sexual intercourse. Large combined microbiological and clinical studies should address this important issue.

We aimed to assess the intestinal colonization dynamics by multiple extended-spectrum cephalosporin-resistant Enterobacteriaceae (ESC-R-Ent) clones in Swiss travelers to India, a country with high prevalence of these multidrug-resistant pathogens. Fifteen healthy volunteers (HVs) colonized with ESC-R-Ent after traveling to India who provided stools before, after, and at 3- and 6-month follow-up are presented in this study. Stools were enriched in a LB broth containing 3 mg/L cefuroxime and plated in standard selective media (BLSE, ChromID ESBL, Supercarba) to detect carbapenem- and/or ESC-R-Ent. At least 5 Enterobacteriaceae colonies were analyzed for each stool provided. All strains underwent phenotypic tests (MICs in microdilution) and molecular typing to define bla genes (microarray, PCR/sequencing), clonality (MLST, rep-PCR), and plasmid content. While only three HVs were colonized before the trip, all participants had positive stools after returning, but the colonization rate decreased during the follow-up period (i.e., six HVs were still colonized at both 3 and 6 months). More importantly, polyclonal acquisition (median of 2 clones, range 1–5) was identified at return in all HVs. The majority of the Escherichia coli isolates belonged to phylogenetic groups A and B1 and to high diverse non-epidemic sequence types (STs); however, 15% of them belonged to clonal complex 10 and mainly possessed blaCTX−M−15 genes. F family plasmids were constantly found (~80%) in the recovered ESC-R-Ent. Our results indicate a possible polyclonal acquisition of the ESC-R-Ent via food-chain and/or through an environmental exposure. For some HVs, prolonged colonization in the follow-up period was observed due to clonal persistence or presence of the same plasmid replicon types in a new bacterial host. Travel medicine practitioners, clinicians, and clinical microbiologists who are facing the returning travelers and their samples for different reasons should be aware of this important phenomenon, so that better infection control measures, treatment strategies, and diagnostic tests can be adopted.

Two homosexual men were colonized in the urethra with Haemophilus parainfluenzae nonsusceptible to ampicillin (MIC, 8 g/ ml), amoxicillin-clavulanate (MIC, 4 g/ml), cefotaxime (MIC, 1.5 g/ml), cefepime (MIC, 3 g/ml), meropenem (MIC, 0.5 g/ ml), cefuroxime, azithromycin, ciprofloxacin, tetracycline, and chloramphenicol (all MICs, >32 g/ml). Repetitive extragenic palindromic PCR (rep-PCR) showed that the strains were indistinguishable. The isolates had amino acid substitutions in PBP3, L4, GyrA, and ParC and possessed Mef(A), Tet(M), and CatS resistance mechanisms. This is the first report of extensively drugresistant (XDR) H. parainfluenzae.