Microbiological identification and resistance profile of microorganisms in pressure injuries after the use of polyhexamethylene biguanide: a series of fourteen cases.

INTRODUCTION: Colonization of a pressure injury with microorganisms can negatively affect wound healing. Thus, it is necessary to evaluate which products best facilitate wound healing. OBJECTIVE: This case series evaluated the effectiveness of the antimicrobial polyhexamethylene biguanide (PHMB) on microorganisms in pressure injuries. MATERIALS AND METHODS: Fourteen patients (14 wounds) were treated with PHMB in the hospital setting after collection of a wound swab sample for microbiological analysis and determination of the risk profile using the disk diffusion method. RESULTS: Thirteen lesions (92.9%) were positive for 1 or more bacterial strains, the most prevalent of which were Staphylococcus aureus and Pseudomonas aeruginosa. Two strains of methicillin-resistant S aureus (MRSA) were also identified. Klebsiella pneumoniae demonstrated 100% resistance to the tested antibiotics, with Acinetobacter demonstrating 90% resistance, P aeruginosa 88.9%, Citrobacter freundii 87.5%, S aureus 66.7%, and MRSA 57.1%. Only Serratia marcescens demonstrated no resistance to any antibiotic tested. Polyhexamethylene biguanide was effective only against strains of S marcescens, which were not present in the second wound swab sample collected (after the application of PHMB); other microorganisms were present in the second wound swab sample collected. CONCLUSIONS: Polyhexamethylene biguanide has an immediate antimicrobial effect on S marcescens. However, it had no qualitative effect on the other microorganisms. Studies with larger populations and randomized clinical trial methodologies are necessary to elucidate additional findings concerning the effectiveness of PHMB in managing microorganisms in pressure injuries.

Genomic analysis of Burkholderia cenocepacia isolated from a liver abscess in a patient with cystic fibrosis.

Burkholderia cenocepacia complex is associated with high transmissibility, virulence, and poor prognosis in cystic fibrosis (CF) patients. However, extrapulmonary infections are rare. We investigated the genome of a B. cenocepacia IIIA isolated from a liver abscess in a Brazilian CF patient and compared it to strain J2315. The whole genome was sequenced, and contigs were annotated by Rapid Annotation using Subsystem Technology. The Pathosystems Resource Integration Center was used to map antimicrobial and virulence genes. The genomic island (GIs) analysis was performed using two prediction methods, and the presence of putative plasmids and insertion sequences (ISs) was investigated. The isolate was confirmed as B. cenocepacia IIIA to ST-28 (ET12 lineage). A total of 64 genes for antimicrobial resistance and 47 genes related to virulence were identified. Among the virulence factors, there was a predominance of factors related to the invasion mechanism, to the flagellar biosynthesis protein, and to the RNA polymerase sigma factor for flagellar operon (cdpA). Two IS families (IS3 and IS5) and only one plasmid were found. On average 56 GIs were predicted by at least one of the methods applied. Comparative analysis showed resistance mechanisms and virulence factors revealing invasive determinants used by B. cenocepacia IIIA (ET12) in the process of disease spread to other infection sites (extrapulmonary) of highly virulent strains in CF patients.