Comparative evaluation of aggressiveness traits in staphylococcal strains from severe infections versus nasopharyngeal carriage.

Despite their commensal status, staphylococci can become problematic pathogens expressing multiple and redundant virulence factors. This study aimed to evaluate aggressiveness markers comparatively in staphylococcal strains isolated from severe infections versus asymptomatic carriage in order to identify clinically relevant bacterial traits that could easily be detected in clinical practice and could be suggestive for particular host-pathogen interactions such as cyto-adhesion or biofilm formation, ultimately orienting the clinical decision-making process. We have used in vitro phenotypic methods to assess adhesion to and invasion of eukaryotic cells, biofilm development, and expression of soluble virulence factors in 92 Staphylococcus spp. strains. The adhesion index, invasion capacity, biofilm formation and expression of soluble factors did not differ significantly between clinical and commensal strains. The major bacterial traits we found to be significantly more prevalent in clinical staphylococci were the aggregative adhesion pattern (P = 0.012), cluster adhesion (P = 0.001) and tetrad morphology (P = 0.018). The aggregative adhesion pattern was correlated with higher cyto-adhesion (P < 0.001), higher invasion capacity (P = 0.003) and lower Carmeli scores (P = 0.002). Three major bacterial traits, namely tetrad morphology, aggregative adhesion pattern, and resistance to methicillin (acronym: TAM), can be used to compute an aggressiveness score (SAS) predictive of the staphylococcal strain's virulence and capacity to initiate and develop a biofilm-driven chronic infectious process versus a fulminant acute infection, in a susceptible host.

Microbiologic Safety of the Transareolar Approach in Breast Augmentation.

BACKGROUND: In aesthetic breast augmentation, especially by the transareolar approach, there is increasing concern regarding the occurrence of capsular contracture and its potential correlation with intraoperative implant contamination from putative endogenous breast flora of the nipple and lactiferous ducts. However, detectable bacteria cannot be considered synonymous with established resident microflora. OBJECTIVES: The authors sought to elucidate the existence of endogenous breast flora and assess the microbiologic safety of transareolar breast augmentation. METHODS: In this prospective study (BREAST-MF), the authors collected microbiologic samples from the breast skin, ductal tissue, and parenchyma of 39 consecutive female patients who underwent breast procedures in a plastic surgery clinic. Swabs collected pre-, intra-, and postoperatively were processed for bacterial and fungal growth. Positive cultures underwent identification through VITEK and MALDI-TOF, as well as antimicrobial susceptibility testing. RESULTS: Staphylococcus species accounted for 95 of 106 (89.6%) positive results from native breast skin, 15 of 18 (83.3%) positive results from decontaminated breast skin, and 4 of 4 (100%) positive results from the breast parenchyma. Methicillin resistance was present in 26.4% of S. epidermidis, 25.3% of S. hominis, and 71.4% of S. haemolyticus strains. CONCLUSIONS: During transareolar breast augmentation, in the nipple-areola region it is more likely to find bacteria populating the skin, rather than endogenous breast flora, as previously considered. Appropriate preoperative decontamination is essential for minimizing the risk of postoperative infections. LEVEL OF EVIDENCE 3: Risk.

Bacteriophage-driven inhibition of biofilm formation in Staphylococcus strains from patients attending a Romanian reference center for infectious diseases.

The increasing burden of invasive biofilm-related staphylococcal infections has led to a dire need for new agents to prevent biofilm formation. Bacteriophages may hypothetically alter a biofilm through several mechanisms, including induction of depolymerizing enzymes and lysis of persistent bacteria. We have assessed the influence of commercially available bacteriophage cocktails on Staphylococcus spp. clinical strains viability and biofilm formation. We analyzed 83 staphylococcal strains from patients consecutively admitted to a Romanian infection reference center from October 2014 through May 2015; the strains were characterized by phenotypic and genetic tools for their resistance and virulence features and for their phyliation. Experiments were performed in triplicate. Methicillin-susceptible strains were significantly more susceptible to all tested phages: 1.7-fold higher susceptibility for PYO, 1.4-fold for INTESTI, 2.9-fold for PHAGYO, 2.7-fold for PHAGESTI and 3.9-fold for STAPHYLOCOCCAL; t030 strains were significantly more susceptible to PYO and INTESTI compared with t127 strains. We identified a significant decrease in biofilm formation in the presence of both low and high PYO and INTESTI concentrations (P < 0.001). In conclusion, Staphylococcus strains from Romania displayed fairly good susceptibility to commercially available bacteriophages. We have also ascertained there is phage-driven in vitro inhibition of biofilm formation, the results potentially impacting prevention of prosthetic infections.

Experimental approach for bacteriophage susceptibility testing of planktonic and sessile bacterial populations - Study protocol.

INTRODUCTION: Antimicrobial resistance is a growing threat for all clinical branches. This phenomenon poses important challenges in controlling infectious diseases. However, multidrug resistance is not the only issue, as bacteria that are otherwise susceptible to common antibiotics express other patterns for evading antibiotherapy, for example they can aggregate within a self-produced matrix to form biofilm. METHODS: We intend to perform a prospective laboratory study of the germs isolated from different samples collected from patients admitted with infectious pathology in reference hospitals in Romania. We will perform antibiotic resistance testing as well as phage testing, both on solid and liquid growth medium, for Staphylococcus spp., Enterococcus spp., and Pseudomonas spp. We intend to collect data for 150 patients with different infections with these identified pathogens. Phage susceptibility testing will be performed using 5 types of strain-specific bacteriophage mixtures: PYO, INTESTI, STAPHYLOCOCCAL (Eliava BioPreparations, Tbilisi, Georgia), PHAGYO, PHAGESTI (JSC "Biochimpharm", Tbilisi, Georgia). For phage-susceptible strains, we will evaluate biofilm formation in the presence of phages, as well as phage effect on already formed biofilm. EXPECTED RESULTS: Through this study, we intend to provide the first set of results on bacteriophage-susceptibility of bacteria isolated from patients with hard to treat infections, from reference hospitals in Romania. By evaluating a large number of bacterial strains we aim to predict and project biofilm kinetics, while adding binary phage dilutions at key timepoints during biofilm formation. ACKNOWLEDGMENTS: POSDRU/159/1.5/S/141531; Carol Davila University of Medicine and Pharmacy, Young Researchers Grant no. 28341/2013.

BReast Ecology Assessment in the STudy of local MicroFlora - Study Protocol.

INTRODUCTION: Recent articles have described an endogenous breast flora, particularly in the nipple ducts, with potential implications in the outcome of aesthetic breast surgery. To characterize the ecology of the breast, we designed a study to assess the microbial species identified on the breast skin and parenchyma in patients undergoing breast surgical interventions. METHODS: AFTER OBTAINING INFORMED CONSENT AND BACKGROUND DATA ON CONCURRENT DISEASES, PREVIOUS CONTACT WITH THE HOSPITAL SYSTEM AND PRIOR USE OF ANTIBIOTICS, SAMPLES ARE COLLECTED PREOPERATIVELY FROM THREE AREAS OF THE BREAST SKIN, BILATERALLY: the inframammary fold, the areola and the axilla, prior to decontamination. These samples will serve as positive controls and will aid in characterizing the normal breast skin flora. After preoperative decontamination, samples are again collected, to check for any residual bacterial flora and the nipple is sealed with Tegaderm (3M, USA) and betadine ointment, to reduce any putative bacterial load. Intraoperatively, samples are collected from: a) the incision line (dermal level): 1. superficially, 2. medium depth in the breast parenchyma, 3. deep parenchyma, and b) axillary parenchyma (where possible), together with a bioptic fragment. Postoperatively, a second nipple sample is collected. For secondary breast augmentation surgeries, capsular biopsy is also performed (where relevant), and the implants undergo sonication, to allow biofilm identification. In the laboratory, all samples are cultured on blood agar incubated with CO2, cystine lactose electrolyte deficient medium and Sabouraud gentamicin-chloramphenicol agar. For positive culture samples, the number of colonies and their morphologic characteristics are reported. Identification will be carried out with MALDI-TOF and VITEK (bioMérieux, France), yielding automated antibiotic sensitivity profiles. For all germs with sensitivity profiles differing from the wild-type strain, E-tests will be performed. Follow-up information on the postoperative evolution will be collected and analyzed for potential factors predictive of good evolution. DISCUSSION: This study will provide important information about the microflora of the breast skin, its sensitivity profile, and the degree of contamination of the nipple ducts and parenchyma, if any, addressing a scientific hypothesis insufficiently explored so far.