Multidrug-Resistant Methicillin-Resistant Staphylococcus aureus Associated with Bacteremia and Monocyte Evasion, Rio de Janeiro, Brazil.

We typed 600 methicillin-resistant Staphylococcus aureus (MRSA) isolates collected in 51 hospitals in the Rio de Janeiro, Brazil, metropolitan area during 2014-2017. We found that multiple new clonal complex (CC) 5 sequence types had replaced previously dominant MRSA lineages in hospitals. Whole-genome analysis of 208 isolates revealed an emerging sublineage of multidrug-resistant MRSA, sequence type 105, staphylococcal cassette chromosome mec II, spa t002, which we designated the Rio de Janeiro (RdJ) clone. Using molecular clock analysis, we hypothesized that this lineage began to expand in the Rio de Janeiro metropolitan area in 2009. Multivariate analysis supported an association between bloodstream infections and the CC5 lineage that includes the RdJ clone. Compared with other closely related isolates, representative isolates of the RdJ clone more effectively evaded immune function related to monocytic cells, as evidenced by decreased phagocytosis rate and increased numbers of viable unphagocytosed (free) bacteria after in vitro exposure to monocytes.

Clinical and Microbiological Outcomes Associated With Use of Platelet-Rich Plasma in Chronic Venous Leg Uclers: A Randomized Controlled Trial.

PURPOSE: To evaluate the susceptibility profiles of Staphylococcus aureus and Pseudomonas aeruginosa strains identified in chronic venous ulcers treated with platelet-rich plasma (PRP) and petrolatum gauze or petrolatum gauze alone and to quantitatively evaluate the bacterial load and biofilm-forming capacities of the detected S. aureus and P. aeruginosa strains. DESIGN: Randomized controlled trial. SUBJECTS AND SETTING: The convenience sample included 36 participants; 18 were allocated to the PRP combined with the petrolatum gauze group, and 18 were allocated to the control group, which was treated with petrolatum gauze alone. METHODS: Thirty-six patients presenting with chronic venous ulcers were consecutively randomized to the PRP group (n = 18) or the petrolatum gauze control group (n = 18). We followed participants for 3 months during treatment and collected swab cultures from their wounds during weeks 1, 6, and 12 or until the wounds healed. The samples were analyzed using mass spectrometry. Antimicrobial susceptibility tests were performed using disk diffusion. RESULTS: P. aeruginosa was identified in 39 (39%) of 100 samples, and S. aureus was detected in only 10 (10%) samples collected over the study period. At the end of the 12-week treatment period, the wound infections reduced in both the PRP (P = .0078) and control groups (P = .01). The microorganisms were susceptible to most of the tested antimicrobials. The PRP did not increase the bacterial load in the wounds. All S. aureus strains identified showed biofilm-forming capacities and were classified as weak biofilm producers. All P. aeruginosa strains produced biofilm, with 17 strains being classified as weak, 14 as moderate, and 8 as strong biofilm producers. CONCLUSIONS: The PRP plus petrolatum gauze did not increase bacteriological growth or the microbial load in chronic venous ulcers compared with petrolatum gauze alone and could be a considered as an advanced treatment option for these types of chronic wounds.

Prevalence, Antimicrobial Susceptibility, and Clonal Diversity of Pseudomonas aeruginosa in Chronic Wounds.

PURPOSE: Our purposes in this study were to (1) identify Pseudomonas aeruginosa strains collected from swabs of chronic wounds, (2) evaluate the susceptibility of P. aeruginosa strains to various antimicrobials, (3) detect the presence of virulence factors exoenzyme S (exoS) and exoenzyme U (exoU) in P. aeruginosa strains, and (4) evaluate wound colonization by P. aeruginosa via pulsed-field gel electrophoresis (PFGE). DESIGN: Descriptive research using a quantitative approach. SAMPLE AND SETTING: Swabs from 43 adults with chronic wounds treated in an outpatient setting in Niterói City, Brazil, were included using convenience sampling. METHODS: Swabs were collected at 2 points during treatment, 30 to 45 days apart. P. aeruginosa isolates were identified using matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry. Antimicrobial susceptibility testing was performed using the disk diffusion method. The presence of exoS and exoU genes was evaluated using polymerase chain reaction. Genotyping diversity was determined through PFGE. RESULTS: Forty-eight P. aeruginosa isolates were detected in chronic wounds, and 3 were multidrug resistant (6%). Resistance to aztreonam and ciprofloxacin was observed in 48% and 27% of isolates, respectively. The presence of the exoS gene was verified in 54% of isolates, and 27% were positive for the exoU gene. In most wounds, P. aeruginosa strains had the same genetic characteristics at the 2 time points analyzed, indicating that the wound beds remained colonized. CONCLUSIONS: P. aeruginosa was present in 75% of tested chronic wound samples, and the same clones persisted for more than 1 month. In addition, most bacteria contained virulence genes that were associated with high potential to establish infection. The use of silver in chronic wounds may be associated with multidrug resistance in P. aeruginosa; therefore, it is important to avoid colonization by these bacteria.

The antimicrobial susceptibility, biofilm formation and genotypic profiles of Staphylococcus haemolyticus from bloodstream infections.

We analysed the antimicrobial susceptibility, biofilm formation and genotypic profiles of 27 isolates of Staphylococcus haemolyticus obtained from the blood of 19 patients admitted to a hospital in Rio de Janeiro, Brazil. Our analysis revealed a clinical significance of 36.8% and a multi-resistance rate of 92.6% among these isolates. All but one isolate carried the mecA gene. The staphylococcal cassette chromosome mec type I was the most prevalent mec element detected (67%). Nevertheless, the isolates showed clonal diversity based on pulsed-field gel electrophoresis analysis. The ability to form biofilms was detected in 66% of the isolates studied. Surprisingly, no icaAD genes were found among the biofilm-producing isolates.