Methicillin-Resistant Staphylococcus haemolyticus Displaying Reduced Susceptibility to Vancomycin and High Biofilm-Forming Ability

Background: Staphylococcus haemolyticus is one of the most frequently coagulase-negative staphylococci isolated from healthcare-associated infections, mainly those related to implanted medical devices. Objectives: This study aimed to determine the antimicrobial susceptibility profile and biofilm forming capacity of S. haemolyticus isolated from bloodstream infections. Methods: A total of 40 S. haemolyticus isolates were characterized according to their genetic relatedness by repetitive element sequence based-PCR (REP-PCR), antimicrobial susceptibility profile, SCCmec typing, ability to form biofilm on abiotic surface and occurrence of putative genes related to biofilm formation. Results: One S. haemolyticus was susceptible to all antimicrobials. The other isolates (n=39) were resistant to cefoxitin; and among them 34 (87.2%) harbored the mecA gene into the SCCmec type I (5.9%), type III (29.4%), type IV (5.9%) and type V (20.6%); and 38.2% isolates were designated as NT. Apart from cefoxitin, 94.9% of the isolates were resistant to at least four antimicrobial classes, and 32.5% displayed minimal inhibitory concentration (MIC) values higher than 4.0 µg/mL for vancomycin. All isolates formed biofilm on polystyrene surface and were classified as strong biofilm-producers, except for one isolate. All isolates were negative for icaA gene, and the prevalence of the other genes was as follows: atl, 100%; fbp, 92.5%; aap, 90.0%; and bap, 20.0%. Conclusion: This study reports a high prevalence of methicillin-resistant S. haemolyticus displaying decreased susceptibility to vancomycin with the ability to form strong biofilms on abiotic surface. The results support the importance of controlling the adequate use of antimicrobials for the treatment of staphylococcal infections.

Photocatalyst under visible light irradiation inactivates SARS-CoV-2 on an abiotic surface

There is a worldwide attempt to develop prevention strategies against SARS-CoV-2 transmission. Here we examined the effectiveness of visible light-responsive photocatalyst RENECAT™ on the inactivation of SARS-CoV-2 under different temperatures and exposure durations. The viral activation on the photocatalyst-coated glass slides decreased from 5.93±0.38 logTCID50/ml to 3.05±0.25 logTCID50/ml after exposure to visible light irradiation for 6h at 20°C. On the other hand, lighting without the photocatalyst, or the photocatalyst-coat without lighting retained viral stability. Immunoblotting and electron microscopic analyses showed the reduced amounts of spike protein on the viral surface after the photocatalyst treatment. Our data suggest a possible implication of the photocatalyst on the decontamination of the SARS-CoV-2 in indoor environments, thereby preventing indirect viral spread.

DETECTION OF BACTERIAL ETIOLOGY USING BIOLUMINESCENCE METHOD ON CUP LIDS DUE TO THE CHANGE IN THEIR FREQUENCY OF USE – SHORT COMMUNICATION

Nowadays, cup with a drink is an attribute of a modern consumer. It is used for hot drinks (e.g. coffee, tea, hot chocolate) and cold drinks (e.g. fruit juices). Currently, there is a noticeable tendency to replace disposable cups with one reusable cup. The barrier to their reuse (especially the mouthpiece on the lid), is the lack of knowledge about its microbiological state. The aim of the presented research was to estimate the risk of bacterial etiology occurrence on disposable and reused lids. The overall metabolic activity of microorganisms was assessed by measuring ATP using the bioluminescence method. Detection of microorganisms was carried out on the abiotic surface (PP / PS), both on the lids of disposable cups used once and repeatedly. Contact with the personnel's hands was also considered. The results of the experiment indicate that the contact of the lids with the personnel's hands is not a reason for the increasing amount of ATP. The highest amounts of ATP were observed on lids of cups used repeatedly.

The effect of the surgical hemostatic product «Hemoblock»TM on in vitro bacterial colonization

Objective. To evaluate effect of «Haemoblock»TM preparation on in vitro bacterial colonization. Materials and Methods. Activity of «Haemoblock»ТМ product on the growth and colonization of S. aureus АТСС 25923, S. epidermidis ATCC 28922, E. coli АТСС 25922, P. aeruginosa АТСС 27853 cells in the suspension and on the surface of monofilament macroporous polyester mesh was evaluated. Results. This product at concentration of 0.062% and above inhibited bacterial growth and reduced biofilm mass and bacterial cell viability. In addition, the short-term exposure of the mesh implant to the tested product resulted in inhibition of the abiotic surface contamination. Conclusions. «Haemoblock»TM product allows not only to ensure hemostasis in open and laparoscopic surgery, but also to reduce the bacterial cell count in the surrounding tissues in the intra- and post-operative periods.