Staphylococcus schleiferi diabetic foot osteomyelitis and bacteraemia in an immunocompromised host

Clinical characteristics, treatment and efficacy of calcaneal osteomyelitis: A systematic review with synthesis analysis 1118 reported cases

BACKGROUND

Calcaneal osteomyelitis (CO) still poses great challenges to orthopaedic surgeons due to unique anatomic and functional features of the calcaneus. This study summarized the current data regarding clinical characteristics, treatment and efficacy of CO, based on an analysis of literature-reported cases.

MATERIALS AND METHODS

We searched the PubMed, Embase, and Cochrane Library databases to find English and Chinese studies reporting on CO patients between 2000 and 2021, with available data for synthesis analysis. The quality of the included studies was evaluated by the National Institutes of Health (NIH) assessment scale. Effective data were extracted and pooled for analysis.

RESULTS

Altogether 198 studies involving 1118 patients were included, with a male-to-female ratio of 2.3 (724 males and 310 females). The median age at CO diagnosis was 46 years, with a median symptom duration of 3 months. Injury-related infections (524 cases) and diabetic foot infections (336 cases) were the two most common causes, with ulcer (468 cases) and wound sinus or exudation (209 cases) being the predominant symptoms. The overall positive culture rate was 80.2%, with polymicrobial infections accounting for 18.1%. Staphylococcus aureus was the most frequently detected pathogen (42.7%), with fungal-related infections isolated in 17 cases. Although most patients received surgical interventions (96.9%), the recurrence rate was 20.1%. The incidence of infection relapse following partial calcanectomy, total calcanectomy, debridement with implantation of local antibiotics, and debridement with or without flap or skin coverage were 31.7%, 45.0%, 16.8%, and 15.1%, respectively. The overall incidence of limb amputation was 12.4%, with all-cause and CO-related mortalities of 2.8% and 0.2%, separately.

CONCLUSIONS

CO shared similar characteristics with extremity chronic osteomyelitis, primarily affecting young males, with trauma and diabetic foot as the leading causes and Staphylococcus aureus as the most frequently detected pathogen. Despite surgery being the primary treatment modality, clinical outcomes remained unsatisfactory, marked by high rates of infection recurrence and limb amputation.

High prevalence of Panton-Valentine Leucocidin among Staphylococcus coagulans isolated from dogs in Rio de Janeiro

AIMS

The purpose of this study was to characterize the capacity for biofilm formation, antimicrobial resistance rates, and search for genetic determinants of resistance and virulence in the species.

METHODS AND RESULTS

Strains were collected from asymptomatic and infected dogs. Identification was conducted using matrix-assisted laser desorption ionization-time of flight (MALDI-TOF), antimicrobial susceptibility using disk diffusion and PCR targeting mecA. Biofilm formation was evaluated on a microtiter plate assay. A total of 27 strains were selected for whole-genome sequencing. We identified 111 Staphylococcus coagulans. The highest number was obtained from infected dogs. The highest resistance rates were observed for penicillin, gentamicin, and ciprofloxacin/erythromycin. Twelve strains were characterized as resistant to methicillin. All isolates had the ability to form biofilm and were strong producers. Among Methicillin Resistant Staphylococcus coagulans (MRSC), SCCmec types IIIA, and Vc were identified. Acquired resistance genes, such as aac(6')-aph(2''), tet(K), blaZ, qacG, qacJ, and erm(C) were found. Different virulence genes were identified. Of note, Panton-Valentine Leucocidin was highly prevalent among the isolates.

CONCLUSION

Staphylococcus coagulans had a high isolation rate among infected dogs and demonstrated significant resistance to commonly used antibiotics such as penicillin and gentamicin.

Staphylococcus schleiferi: An Uncommon Pathogen in an Immunocompetent Adolescent with Chronic Osteomyelitis

Staphylococcus schleiferi represents an uncommon pathogen in human infections. As a veterinary pathogen, S. schleiferi causes canine ear and skin infections. Chronic osteomyelitis is a progressive process characterized by bone destruction and the formation of sequestrum. It may be a sequela of untreated or undertreated acute osteomyelitis or septic arthritis. Descriptions detailing the pathogenicity and virulence of S. schleiferi osteomyelitis were limited to a few case reports. Among the three reported cases of S. schleiferi osteomyelitis, immunosuppression, malignancy, and recent surgical procedures were comorbidities. Compared to those who are immunosuppressed, immunocompetent individuals are generally not susceptible to uncommon microorganisms. Early detection of osteomyelitis, aggressive appropriate prolonged antimicrobial treatment and a multidisciplinary approach contribute to optimal recovery. We report the first case of S. schleiferi chronic osteomyelitis in an immunocompetent adolescent.

Phenotypic and Genotypic Virulence Characterisation of Staphylococcus pettenkoferi Strains Isolated from Human Bloodstream and Diabetic Foot Infections

Staphylococcus pettenkoferi is a recently described coagulase-negative Staphylococcus identified in human diseases, especially in infections of foot ulcers in patients living with diabetes mellitus. To date, its pathogenicity remains underexplored. In this study, whole-genome analysis was performed on a collection of 29 S. pettenkoferi clinical strains isolated from bloodstream and diabetic foot infections with regard to their phylogenetic relationships and comprehensive analysis of their resistome and virulome. Their virulence was explored by their ability to form biofilm, their growth kinetics and in an in vivo zebrafish embryo infection model. Our results identified two distinct clades (I and II) and two subclades (I-a and I-b) with notable genomic differences. All strains had a slow bacterial growth. Three profiles of biofilm formation were noted, with 89.7% of isolates able to produce biofilm and harbouring a high content of biofilm-encoding genes. Two virulence profiles were also observed in the zebrafish model irrespective of the strains' origin or biofilm profile. Therefore, this study brings new insights in S. pettenkoferi pathogenicity.

A Case of Septic Arthritis Caused by Staphylococcus schleiferi

Septic arthritis leads to significant hospital burden in the United States adult patient population. Bacteria are the leading cause of septic arthritis with Staphylococcus aureus being the most common. Of the staphylococcal species, Staphylococcus ​​​​​​​schleiferi, primarily found in carnivores, rarely causes septic arthritis. We here report the presentation, diagnosis, treatment, and discharge of a 39-year-old male with S. schleiferi septic arthritis. Due to biochemical similarities, S. schleiferi are commonly misidentified as S. aureus, and correct identification is increasingly relevant for the selection of appropriate therapy due to the rise in cases of multidrug-resistant microorganisms.