Treatment with Vancomycin Loaded Calcium Sulphate and Autogenous Bone in an Improved Rabbit Model of Bone Infection.

Bone infection results from bacterial invasion, which is extremely difficult to treat in clinical, orthopedic, and traumatic surgery. The bone infection may result in sustained inflammation, osteomyelitis, and eventual bone non-union. Establishment of a feasible, reproducible animal model is important to bone infection research and antibiotic treatment. As an in vivo model, the rabbit model is widely used in bone infection research. However, previous studies on rabbit bone infection models showed that the infection status was inconsistent, as the amount of bacteria was variable. This study presents an improved surgical method for inducing bone infection on a rabbit, by blocking the bacteria in the bone marrow. Then, multi-level evaluations can be carried out to verify the modelling method. In general, debriding necrotic tissue and implantation of vancomycin-loaded calcium sulphate (VCS) are predominant in antibiotic treatment. Although calcium sulphate in VCS benefits osteocyte crawling and new bone growth, massive bone defects occur after debriding. Autogenous bone (AB) is an appealing strategy to overcome bone defects for the treatment of massive bone defects after debriding necrotic bone. In this study, we used the tail bone as an autogenous bone implanted in the bone defect. Bone repair was measured using micro-computed-tomography (micro-CT) and histological analysis after animal sacrifice. As a result, in the VCS group, bone non-union was consistently obtained. In contrast, the bone defect areas in the VCS-AB group were decreased significantly. The present modeling method described a reproducible, feasible, stable method to prepare a bone infection model. The VCS-AB treatment resulted in lower bone non-union rates after antibiotic treatment. The improved bone infection model and the combination treatment of VCS and autogenous bone could be helpful in studying the underlying mechanisms in bone infection and bone regeneration pertinent to traumatology orthopedic applications.

Draft genome sequence of a multidrug-resistant OXA-23-producing Acinetobacter baumannii ST191 clinical isolate from China.

Acinetobacter baumannii has emerged worldwide as a dominant pathogen in nosocomial infections. In this study, we report the draft genome sequence of a clinical multidrug-resistant (MDR) A. baumannii ST191 (CC92) strain. Whole-genome sequencing of the isolate was performed using an Illumina HiSeq™ 2500 system, and bioinformatics analysis was also performed. The draft genome length was 4,259,210bp, harbouring 14 gene sequences relevant to antibiotic resistance. Antimicrobial susceptibility testing revealed that the isolate was resistant to all of the tested antibiotics except for tigecycline and colistin. These data will facilitate further understanding of the genomic and resistance features of MDR A. baumannii.

An improved method on isolation and serial passage of Chlamydia pneumoniae from human peripheral blood mononuclear cells.

BACKGROUND: Conventional method for Chlamydia pneumoniae (Cpn) isolation and propagation is technically challenging and time-consuming. Here, we developed a method to improve the isolation and passage of Cpn collected from human peripheral blood mononuclear cells (PBMCs). METHODS: PBMCs positive with Cpn antigen (Cpn-Ag) were isolated, then centrifuged and cultured with Hep-2 cells after being broken. Cells were broken again and put into new Hep-2 cells to finish totally four passages with isolated and imported Cpn. Microimmunofluorescence method was used to detect Cpn. Inclusion forming unit (IFU) number was counted for each passage. Polymerase chain reaction (PCR) method was used to detect Cpn DNA. Efficiency of different centrifugation modes was compared. RESULTS: Hep-2 cells of the first and second passages were strong positive with Cpn-Ag, the third passage was positive, and the fourth negative. Degeneration appeared in the fourth passage for isolated Cpn and third passage for imported strain. Centrifugation mode of 1,000 rpm for 2 h was the most efficient for Cpn propagation and passage. CONCLUSION: This simplified method achieved efficient isolation, propagation, and passage of Cpn from PBMCs, and isolated strain was superior to imported strain on propagating ability.