Prevalence of fibronectin-binding protein (FnbA and FnbB) genes among clinical isolates of methicillin resistant Staphylococcus aureus

Transition metal complex laminated bioactive implant alleviates Methicillin Resistant Staphylococcus aureus virulence

Orthopedic implant infections cause a serious threat after implantation. The major source of implant infection is biofilms which are highly tolerant to antibiotics due to the presence of rigid biofilm matrix. Hence to overcome biofilm mediated implant infections, we developed a novel antibiofilm agent, palladium (II) thiazolinyl picolinamide complex (Pd(II)-E). From our study, it was found that Pd(II)-E have profound biofilm inhibition activity and also reduced various virulence factors of Methicillin resistant Staphylococcus aureus (MRSA) including slime synthesis, Phenol soluble modulin (PSM) mediated spreading, Exopolysaccharides production and staphyloxanthin synthesis. Further, Pd(II)-E was coated over the titanium plates which was confirmed using EDX (Energy Dispersive X-Ray) analysis. The Pd(II)-E coated plates were able to prevent the biofilm formation on them which was evident under a Scanning electron microscope (SEM) and several virulent genes were found to be downregulated in the biofilms on the coated titanium plates which confirmed by qPCR. From our findings, it was found that Pd(II)-E coated titanium implants would be an effective alternate approach for preventing biofilm mediated implant infections.

Pathogenesis of Staphylococcus haemolyticus on primary human skin fibroblast cells

STAPHYLOCOCCUS HAEMOLYTICUS

(S. haemolyticus) is one of the Coagulase-negative staphylococci (CoNS) that inhabits the skin as a commensal. It is increasingly implicated in opportunistic infections, including diabetic foot ulcer (DFU) infections. In contrast to the abundance of information available for S. aureus and S. epidermidis, little is known about the pathogenicity of S. haemolyticus, despite the increased prevalence of this pathogen in hospitalized patients. We described, for the first time, the pathogenesis of different clinical isolates of S. haemolyticus isolated from DFU on primary human skin fibroblast (PHSF) cells. Virulence-related genes were investigated, adhesion and invasion assays were carried out using Giemsa stain, transmission electron microscopy (TEM), MTT and flowcytometry assays. Our results showed that most S. haemolyticus carried different sets of virulence-related genes. S. haemolyticus adhered to the PHSF cells to variable degrees. TEM showed that the bacteria were engulfed in a zipper-like mechanism into a vacuole inside the cell. Bacterial internalization was confirmed using flowcytometry and achieved high intracellular levels. PHSF cells infected with S.haemolyticus suffered from amarked decrease in viability and increased apoptosis when treated with whole bacterial suspensions or cell-free supernatants but not with heat-treated cells. After co-culture with PBMCs, S. haemolyticus induced high levels of pro-inflammatory cytokines. This study highlights the significant development of S. haemolyticus, which was previously considered a contaminant when detected in cultures of clinical samples. Their high ability to adhere, invade and kill the PHSF cells illustrate the severe damage associated with DFU infections.

ABBREVIATIONS

CoNS, coagulase-negative staphylococci; DFU, diabetic foot ulcer; DM, diabetes mellitus; DMEM, Dulbecco's Modified Eagle Medium; MTT, 3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide; PBMCs,peripheral blood mononuclear cells; PHSF, primary human skin fibroblast; CFU, colony-forming unit.

Bacterial adhesion to collagens: implications for biofilm formation and disease progression in the oral cavity

Collagen is the most abundant structural protein in the body and the main component of the extracellular matrix of most tissues, including dentine and periodontal tissues. Despite the well-characterized role of collagen and specifically type-I collagen, as a ligand for host cells, its role as a substrate for bacterial adhesion and biofilm formation is less explored. Therefore, the purpose of this review is to discuss recent findings regarding the adhesion of oral bacteria to collagen surfaces and its role in the progression and severity of oral and systemic diseases. Initial oral colonizers such as streptococci have evolved collagen-binding proteins (cbp) that are important for the colonization of dentine and periodontal tissues. Also, periodontal pathogens such as Porphyromonas gingivalis and Tannerella forsythia utilise cbps for tissue sensing and subsequent invasion. The implications of bacteria-collagen coupling in the context of collagen biomaterials and regenerative dentistry approaches are also addressed. Furthermore, the importance of interdisciplinary techniques such as atomic force microscopy for the nanocharacterization of bacteria-collagen interactions is also considered. Overall, understanding the process of oral bacterial adhesion onto collagen is important for developing future therapeutic approaches against oral and systemic diseases, by modulating the early stages of biofilm formation.

Status of Biofilm-Forming Genes among Jordanian Nasal Carriers of Methicillin-Sensitive and Methicillin-Resistant Staphylococcus aureus

Introduction:

Biofilm formation in Staphylococcusaureus is a major virulence factor. Both MSSA and MRSA are common causes of community- and hospital-acquired infections and are associated with biofilm formation. The status of biofilm-forming genes has not been explored in Jordanian nasal carriers of S. aureus. This study investigates antibiotic resistance patterns and the prevalence of biofilm-forming genes between MSSA and MRSA in two distinct populations in Jordan.

Methods:

A total of 35 MSSA and 22 MRSA isolates were recovered from hospitalized patients and medical students at Prince Hamzah Hospital, Jordan. Antibiotic susceptibility was tested using disk diffusion method and Vitek 2 system. The phenotypic biofilm formation was tested using CRA and microtiter plate assays. The prevalence of the biofilm-forming genes was determined using multiplex PCR.

Results:

Among 57 S.aureus isolates, 22 (38.6%) isolates were MRSA and were highly resistant against benzylpenicillin, oxacillin, and imipenem. The frequencies of the icaADBC were 77.1%, 97.1%, 94.3%, and 97.1% respectively in MSSA compared to 86.4%, 100%, 100%, and 100% in MRSA isolates. On the other hand, the frequency of the fnbA, fnbB, clfA, fib, clfB, ebps, eno, and cna genes was 81.8%, 90.9%, 95.5%, 90.9%, 86.4%, 100%, 100%, and 40.9%, respectively in the MRSA isolates.

Conclusion:

In both groups, MRSA isolates, in comparison to MSSA, were significantly more resistant to cefoxitin, oxacillin, imipenem, tetracycline, clindamycin, and trimethoprim-sulfamethoxazole. Unexpectedly, biofilm formation and gene prevalence between MRSA and MSSA isolates showed no significant difference, suggesting other potential virulence mechanisms.