Cecilia Girbau

PCR-Restriction Fragment Length Polymorphism Assay for Detection of gyrA Mutations Associated with Fluoroquinolone Resistance in Campylobacter coli

ABSTRACT A fragment of the gyrA gene was sequenced from 34 isolates of Campylobacter coli, including 23 isolates resistant to ciprofloxacin. All ciprofloxacin-resistant isolates examined by DNA sequencing carried a point mutation at position Thr-86 on the gyrA gene product, involving the replacement of Thr-86 by Ile. A combined PCR-restriction fragment length polymorphism technique using RsaI was developed to detect this mutation.

Prevalence and genetic diversity of arcobacter in food products in the north of Spain.

The bacterial contamination of food products can cause serious public health problems. Interest in Arcobacter contamination has increased due to the relationship between these bacteria and human enteritis. We studied the prevalence and genetic diversity of Arcobacter species at the retail level in the province of Alava in Basque Country, Spain. The results showed a high genetic diversity and indicated the regular presence of the main Arcobacter spp. associated with human enteric illness in food products. Arcobacter butzleri, Arcobacter cryaerophilus, and Arcobacter skirrowii were detected with an overall prevalence close to 40% and were isolated from 15 (42.8%) fresh cows milk samples, 12 (73.3%) shellfish samples, 11 (55%) chicken samples, 2 (10%) pork samples, and 1 (5%) beef sample. The results indicate the need to investigate the impact of Arcobacter spp. on public health.

LL37 loaded nanostructured lipid carriers (NLC): A new strategy for the topical treatment of chronic wounds

The LL37 is a human antimicrobial peptide which not only has a broad spectrum of antimicrobial activity, but it has also been proved to modulate wound healing by participating in angiogenesis, epithelial cell migration and proliferation, and immune response. In this work, LL37 has been encapsulated in nanostructured lipid carriers (NLCs), produced by the melt-emulsification method, in order to improve its effectiveness. The characterisation of the NLC-LL37 showed a mean size of 270nm, a zeta potential of -26mV and an encapsulation efficiency of 96.4%. The cytotoxicity assay performed in Human Foreskin Fibroblasts demonstrated that the NLC-LL37 did not affect cell viability. Moreover, the in vitro bioactivityassay evidenced that the peptide remained active after the encapsulation, since the NLC-LL37 reversed the activation of the macrophages induced by LPS in the same way as the LL37 in solution. In addition, the in vitro antimicrobial assay revealed the NLC-LL37 activity against Escherichia coli. The effectiveness of the nanoparticles was assessed in a full thickness wound model indb/dbmice. The data demonstrated that NLC-LL37 significantly improved healing compared to the same concentration of the LL37 solution in terms of wound closure, reepithelisation grade and restoration of the inflammatory process. Overall, these findings suggest a promising potential of the NLC-LL37 formulation for chronic wound healing.

Multilocus sequence typing reveals genetic diversity of foodborne Arcobacter butzleri isolates in the North of Spain

The emerging pathogen Arcobacter butzleri is being increasingly isolated from different animal food products but the routes of its transmission to human are not well established yet. Typing methods would be useful in gaining such knowledge. Here we report the great genetic diversity observed among A. butzleri isolates from different food products. Forty-five isolates were analyzed by Multilocus Sequence Typing (MLST). A total of 157 alleles were identified across all seven loci, ranging from 16 alleles at glnA to 31 at glyA. MLST differentiated the isolates into 34 sequence types (STs), with the majority of isolates containing a unique sequence type. Seventy-four new alleles were identified, which resulted in the assignment of 33 new STs. No association of alleles or STs with food source was observed. For the first time, lateral gene transfer from Arcobacter skirrowii to A. butzleri at the glyA locus is also reported.

Spread of an Enterococcus faecalis sequence type 6 (CC2) clone in patients undergoing selective decontamination of the digestive tract.

Enterococcus faecalis (E. faecalis) is a common cause of nosocomial infection in immunocompromised patients. The presence and dissemination of high‐risk clonal complexes, such as CC2, is an ongoing problem in hospitals. The aim of this work was to characterize 24 E. faecalis isolates from ICU patients undergoing selective decontamination of the digestive tract (SDD) by phenotypical (antimicrobial susceptibility) and genotypical (presence of virulence genes, RAPD‐PCR and MLST) methods. Our results showed high prevalence of the ST6 E. faecalis clone (91.6%), especially adapted to the hospital environment, with a multidrug resistance pattern and a multitude of putative virulence genes. In addition, ST179 (4.2%) and ST191 (4.2%) were detected. By RAPD–PCR analysis, the 22 isolates identified as ST6 showed six different DNA patterns, while the two remaining isolates, ST179 and ST191, showed two additional profiles. CC2 is a known clonal complex with high adaptability to hospital environment and worldwide distribution. The high prevalence of the ST6 clone in the studied population could be related to the presence of gentamicin in the SDD mixture since most strains were gentamicin resistant. Consequently, strict surveillance should be applied for rapid detection and control of this clone to prevent future spread outside the ICU.

Study of Biofilm Formation Ability of Foodborne Arcobacter butzleri under Different Conditions

The transmission of Arcobacter butzleri , an emerging food- and waterborne pathogen, is possibly favored by its ability to adhere to abiotic surfaces. In this study, we assessed the biofilm formation ability of 42 A. butzleri isolates recovered from different food products. Overall, nine isolates (21.4%) were able to adhere to polystyrene. Among them, a chicken-derived isolate was classified as strongly adherent. Based on the chi-square test, no relation was found between the adhesive abilities of the isolates and their source (P > 0.05). An aerobic atmosphere enhanced the adhesion ability of the majority of the adherent isolates (66.7%), because when tested in microaerobic conditions, a t test indicated that only three isolates increased their biofilm formation ability significantly (P < 0.05). In addition, seven (77.8%) of these nine isolates were able to adhere to glass surfaces, and viable cells were recovered from all the stainless steel coupons tested. Therefore, our results confirm the biofilm formation ability of A. butzleri , which may be influenced by the incubation atmosphere and the abiotic surface.