Clinical features and outcome of bone and joint infections with streptococcal involvement: 5-year experience of interregional reference centres in the south of France

Sterile Setup Table in the Operating Room Is Not So Sterile

BACKGROUND

One of the important factors for surgical site infection prevention is the implementation of an ultraclean operating room. This study was designed to evaluate back-table sterility during total joint arthroplasty.

METHODS

This prospective study includes 52 patients undergoing primary total joint arthroplasty between November 2021 and January 2022. A total of 4 swabs (2 air swabs and 2 table swabs) were obtained for each case, at the conclusion of surgery and prior to the takedown of drapes. One swab from each set was sent for culture, and the other was sent for next-generation sequencing (NGS) analysis.

RESULTS

Among 104 back-table swabs, a total of 13 (12.5%) organisms were isolated. Of these, 7 organisms were isolated by culture and 6 by NGS. No microorganisms were isolated by both culture and NGS from back-table swabs. Among 104 air swabs, a total of 11 (10.6%) organisms were isolated. Of these, 6 microorganisms were isolated by culture and 5 by NGS. In 4 of the 104 swabs, both culture- and NGS-isolated organisms were from air swabs. Of the 104 (12.5%) back-table and air swabs, 13 were culture positive. While more than 1 pathogen was identified in 2 air swabs, all back-table swabs were monomicrobial by culture. Pathogens were identified from 11 of 104 (10.6%) swabs by NGS, while more than 1 pathogen was identified in 4 swabs (2 air and 2 back table).

CONCLUSION

The findings of this study raise an important issue that the surgical field including the sterile table setup for instruments is not "sterile" and can harbor pathogens.

Genomic characterization of beta-haemolytic streptococci isolated from prosthetic joint infections

Prosthetic joint infection (PJI) is an increasing concern for the medical profession, as higher numbers of arthroplasty surgeries lead to rising PJI-related costs. Streptococcal PJIs constitute approximately 10% of PJIs, but their genetic features and characteristics remain largely unexplored. Little is known about antimicrobial resistance (AMR) rates, whether some sequence types (ST) dominate, and whether certain virulence-associated genes are overrepresented. We used whole-genome sequencing of Streptococcus dysgalactiae (n = 22), Streptococcus agalactiae (n = 10) and S. pyogenes (n = 1) to elicit genomic data on 33 beta-haemolytic streptococci isolated from PJIs in Region Örebro county, Sweden. Relatedness was inferred based on single nucleotide polymorphisms in S. dysgalactiae and S. agalactiae. The genomic data were screened for virulence-associated genes available in the Virulence Factor Database. All isolates were screened for both phenotypic and genotypic resistance. The S. dysgalactiae and S. agalactiae isolates were genetically diverse, although 32% of S. dysgalactiae isolates (n = 7) were ST20. The speS and PI-2A genes were less represented in these isolates among virulence-associated genes, and AMR was more frequently observed in S. agalactiae. We conclude that PJIs caused by beta-haemolytic streptococci are not dominated by genetically similar beta-haemolytic streptococci. There were distinct inter-species differences in AMR between S. agalactiae and S. dysgalactiae.

Streptococcal and Staphylococcus aureus prosthetic joint infections: are they really different?

Background

Staphylococci and streptococci are the most frequent pathogens isolated from prosthetic joint infections (PJIs). The aim of this study was to analyze the outcome of streptococcal and methicillin-susceptible Staphylococcus aureus (MSSA) PJIs.

Methods

All monomicrobial streptococcal and MSSA PJIs managed in a French Referral Center (2010–2017) were sampled from the prospective PJIs cohort study. The primary outcome of interest was the cumulative reinfection-free survival at a 2-year follow-up.

Results

Two hundred and nine patients with 91 streptococcal and 132 staphylococcal infections were analyzed. Patients with streptococcal PJI were older, and infection was more frequently hematogenous. Reinfection-free survival rates at 2-years after all treatment strategies were higher for patients with streptococcal PJI (91% vs 81%; P = .012), but differed according to the strategy. After exchange arthroplasty, no outcome differences were observed (89% vs 93%; P = .878); after debridement, antibiotics and implant retention (DAIR), the reinfection-free survival rate was higher for patients with streptococcal PJI (87% vs 60%; P = .062). For patients managed with prolonged suppressive antibiotic therapy (SAT) alone, those with streptococcal PJIs had a 100% infection-free survival (100% vs 31%; P < .0001).

Conclusions

Reinfection-free survival after DAIR and SAT was better for patients with streptococcal than those with MSSA PJIs. No difference was observed after prosthesis exchange.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07532-x.

Ways to Improve Insights into Clindamycin Pharmacology and Pharmacokinetics Tailored to Practice

Given the increase in bacterial resistance and the decrease in the development of new antibiotics, the appropriate use of old antimicrobials has become even more compulsory. Clindamycin is a lincosamide antibiotic approved for adults and children as a drug of choice for systemic treatment of staphylococcal, streptococcal, and gram-positive anaerobic bacterial infections. Because of its profile and high bioavailability, it is commonly used as part of an oral multimodal alternative for prolonged parenteral antibiotic regimens, e.g., to treat bone and joint or prosthesis-related infections. Clindamycin is also frequently used for (surgical) prophylaxis in the event of beta-lactam allergy. Special populations (pediatrics, pregnant women) have altered cytochrome P450 (CYP)3A4 activity. As clindamycin is metabolized by the CYP3A4/5 enzymes to bioactive N-demethyl and sulfoxide metabolites, knowledge of the potential relevance of the drug’s metabolites and disposition in special populations is of interest. Furthermore, drug–drug interactions derived from CYP3A4 inducers and inhibitors, and the data on the impact of the disease state on the CYP system, are still limited. This narrative review provides a detailed survey of the currently available literature on pharmacology and pharmacokinetics and identifies knowledge gaps (special patient population, drug–drug, and drug–disease interactions) to describe a research strategy for precision medicine.

Clinical features and outcome of Streptococcus agalactiae bone and joint infections over a 6-year period in a French university hospital

BACKGROUND

Bone and joint infections (BJIs) due to Streptococcus agalactiae are rare but has been described to increase in the past few years. The objective of this study was to describe clinical features and outcomes of cases of S. BJIs.

METHODS

We conducted a retrospective analysis of adult cases of S. agalactiae BJIs that occurred between January 2009 and June 2015 in a French university hospital. The treatment success was assessed until 24 months after the end of antibiotic treatment.

RESULTS

Among the 26 patients included, 20 (77%) were male, mean age was 62 years ± 13 and mean Charlson comorbidity index score was 4.9 ± 3.2. Diabetes mellitus was the most common comorbidity (n = 14, 54%). Six had PJI (Prosthetic Joint Infections), five osteosynthesis-associated infections, 11 osteomyelitis and four native septic arthritis. Eleven patients had a delayed or late infection: six with a prosthetic joint infection and five with an internal fixation device infection. Sixteen patients (62%) had a polymicrobial BJI, most commonly with Gram-positive cocci (75%) notably Staphylococcus aureus (44%). Polymicrobial infections were more frequently found in foot infections (90% vs 44%, p = 0.0184). During the two-year follow-up, three patients died (3/25, 12%) and seven (7/25, 28%) had treatment failure.

CONCLUSION

Diabetes mellitus was the most common comorbidity. We observed an heterogenous management and a high rate of relapse.

Case Studies and Literature Review of Pneumococcal Septic Arthritis in Adults

We saw an increase in this condition related to emergence of Streptococcus pneumoniae serotype 23B.

We conducted a retrospective study on all cases of pneumococcal septic arthritis (SA) in patients >18 years of age reported to the Picardie Regional Pneumococcal Network in France during 2005–2016. Among 1,062 cases of invasive pneumococcal disease, we observed 16 (1.5%) SA cases. Although SA is uncommon in adult patients, the prevalence of pneumococcal SA in the Picardie region increased from 0.69% during 2005–2010 to 2.47% during 2011–2016 after introduction of the pneumococcal 13-valent conjugate vaccine. We highlight the emergence of SA cases caused by the 23B serotype, which is not covered in the vaccine.

Pyogenic Spondylodiscitis due to Streptococcus constellatus in an Immunocompromised Male Patient: A Case Report and Review of the Literature

Pyogenic spondylodiscitis is a primary infection of the intervertebral disc and is a rare entity. Here, we describe the case of a 64-year-old male patient, a professional breeder, who attended the Emergency Department with sciatica and back pain that was worsening for a week. The patient had no history of surgery or trauma. The patient had poor oral hygiene. Magnetic resonance imaging (MRI) scan showed lumbar spondylodiscitis, and blood cultures revealed Streptococcus constellatus. The patient was initially treated with vancomycin but due to renal failure deterioration, the treatment was changed to daptomycin for 8 weeks. During hospitalization, he endured renal injury and nosocomial respiratory tract infection. The patient was discharged with no further complications. Follow-up revealed improvement of neurological signs. In our case, it seems that poor oral hygiene was the cause of bacteremia, which underlies the importance of a good oral health status in immunocompromised patients not only to prevent but also to successfully eliminate any dental source of infection. S. constellatus is an extremely rare pathogen and to our knowledge only two other cases of pyogenic spondylodiscitis are reported in the literature. Early diagnosis is very important for the prognosis of these patients.

Infections Caused by Group C and G Streptococcus (Streptococcus dysgalactiae subsp. equisimilis and Others): Epidemiological and Clinical Aspects

Streptococci carrying serogroup C and G antigens, and in particular, Streptococcus dysgalactiae subsp. equisimilis (SDSE), are emerging human pathogens that are increasingly isolated from patients with a myriad of infections that range from mundane to life-threatening. SDSE is microbiologically similar to Streptococcus pyogenes. These streptococci frequently cause infections of the throat and skin and soft tissues. Moreover, they may invade the bloodstream and disseminate widely to many deep tissue sites, including the endocardium. Life-threatening invasive infections due to SDSE, including the streptococcal toxic shock syndrome, occur most frequently in patients with severe underlying medical diseases. Treatment with penicillin is adequate under most circumstances, but treatment failure occurs. SDSE may also be resistant to other antibiotic classes including tetracyclines, macrolides, and clindamycin. Most human infections caused by groups C and G streptococci are transmitted from person to person, but infections due to Streptococcus equi subsp. zooepidemicus (and, rarely, to S. equi subsp. equi) are zoonoses. Transmission of these latter species occurs by animal contact or by contamination of food products and has been associated with the development of poststreptococcal glomerulonephritis. Members of the Streptococcus anginosus group, usually classified with the viridans group of streptococci, are associated with a variety of pyogenic infections.

The clinical impact of patients with bloodstream infection with different groups of Viridans group streptococci by using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS)

The accuracy of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for identifying viridans group streptococcus (VGS) was improving. However, the clinical impact of identifying VGS had not been well recognized. Our study had comprehensively studied the clinical manifestations and outcome of VGS blood stream infection by using MALDI-TOF MS for identification.This retrospective study enrolled 312 adult patients with a monomicrobial blood culture positive for VGS. Blood culture was examined through MALDI-TOF MS.The most common VGS species were the Streptococcus anginosus group (38.8%) and Streptococcus mitis group (22.8%). Most species showed resistance to erythromycin (35.6%), followed by clindamycin (25.3%) and penicillin (12.5%). Skin and soft tissue infection and biliary tract infection were significantly related to S. anginosus group bacteremia (P = .001 and P = .005, respectively). S. mitis group bacteremia was related to infective endocarditis and bacteremia with febrile neutropenia (P = .005 and P < .001, respectively). Infective endocarditis was also more likely associated with S. sanguinis group bacteremia (P = .009). S. anginosus group had less resistance rate to ampicillin, erythromycin, clindamycin, and ceftriaxone (P = .019, <.001, .001, and .046, respectively). A more staying in intensive care unit, underlying solid organ malignancy, and a shorter treatment duration were independent risk factors for 30-day mortality. This study comprehensively evaluated different VGS group and their clinical manifestations, infection sources, concomitant diseases, treatments, and outcomes. Categorizing VGS into different groups by MALDI-TOF MS could help clinical physicians well understand their clinical presentations.

Streptococcus agalactiae Non-Pilus, Cell Wall-Anchored Proteins: Involvement in Colonization and Pathogenesis and Potential as Vaccine Candidates

Group B Streptococcus (GBS) remains an important etiological agent of several infectious diseases including neonatal septicemia, pneumonia, meningitis, and orthopedic device infections. This pathogenicity is due to a variety of virulence factors expressed by Streptococcus agalactiae. Single virulence factors are not sufficient to provoke a streptococcal infection, which is instead promoted by the coordinated activity of several pathogenicity factors. Such determinants, mostly cell wall-associated and secreted proteins, include adhesins that mediate binding of the pathogen to host extracellular matrix/plasma ligands and cell surfaces, proteins that cooperate in the invasion of and survival within host cells and factors that neutralize phagocytosis and/or modulate the immune response. The genome-based approaches and bioinformatics tools and the extensive use of biophysical and biochemical methods and animal model studies have provided a great wealth of information on the molecular structure and function of these virulence factors. In fact, a number of new GBS surface-exposed or secreted proteins have been identified (GBS immunogenic bacterial adhesion protein, leucine-rich repeat of GBS, serine-rich repeat proteins), the three-dimensional structures of known streptococcal proteins (αC protein, C5a peptidase) have been solved and an understanding of the pathogenetic role of "old" and new determinants has been better defined in recent years. Herein, we provide an update of our current understanding of the major surface cell wall-anchored proteins from GBS, with emphasis on their biochemical and structural properties and the pathogenetic roles they may have in the onset and progression of host infection. We also focus on the antigenic profile of these compounds and discuss them as targets for therapeutic intervention.

Exploring the arthritogenicity of Streptococcus dysgalactiae subspecies equisimilis

BACKGROUND

During the past decades, Streptococcus dysgalactiae subspecies equisimilis (SDSE) has been increasingly recognized as an important human pathogen. Osteoarticular infections is one of the predominant disease manifestations of SDSE, but the pathogenetic rationale for its arthritogenicity has yet to be unravelled. We aimed to explore if the rising incidence of osteoarticular infections caused by this pathogen in our region emanated from clonal expansion of strains with enhanced tropism for bone and joint tissue components or orthopaedic implants.

RESULTS

Twenty-nine SDSE-isolates associated with osteoarticular infections were retrospectively identified. Their genomic content and affinity for fibronectin, collagen and stainless steel were compared to 24 temporally and geographically matched SDSE blood culture isolates obtained from patients without bone or joint infections. Despite a thorough genetic and phenotypic dissection, neither the presence or absence of any single gene, nor the binding abilities of the SDSE isolates, were predictive of clinical entity. SNP analysis revealed a heterogenous population, and a correlation between phylogenetic relationships and disease manifestation was not evident. However, we identified a strong concordance between phenotypic binding abilities and genetic variations in the pilus-region, also denoted as the FCT-region (Fibronectin binding, Collagen binding and T-antigen). This observation could be related to the ample and varied repertoire of putative adhesins residing within this region, including proteins predicted to adhere to fibronectin and collagen, as well as fibrinogen.

CONCLUSIONS

SDSE strains associated with osteoarticular infections do not emanate from subpopulation characterized by distinct genetic or phenotypic traits. The genetic architecture of the pilus region was predictive of the adhesive properties of the SDSE-isolates, but its role in tissue tropism needs further investigation. To the best of our knowledge, this is the first comprehensive characterization of the genetic landscape of the SDSE pilus region.

Analysis of postoperative and hematogenous prosthetic joint-infection microbiological patterns in a large cohort

OBJECTIVES

This study was undertaken to analyze prosthetic joint infection (PJI)-causing microorganisms and compare their distribution patterns according to PJI classification.

METHODS

Cohort study from a single referral center for bone-and-joint infections from January 2004 to December 2015.

RESULTS

Nine hundred and twenty-six patients, who developed 997 PJIs, involving the hip (62%), knee (35%) and/or shoulder (1%), were included. PJIs were classified as early postoperative (19%), late chronic (30%), hematogenous (35%) and undetermined (16%). Pathogens most frequently isolated from early-postoperative PJIs were staphylococci (57%), with 25% each Staphylococcus aureus or Staphylococcus epidermidis; 21% were polymicrobial and 10% Gram-negative rods. For late-chronic PJIs, the most frequent microbes were staphylococci (61%), predominantly S. epidermidis (35%); anaerobic bacteria were isolated from 15%; 11% were polymicrobial. Hematogenous PJIs were 99% monomicrobial. Although S. aureus was the most frequently isolated species (28%), streptococci were isolated slightly more often than staphylococci (39% vs. 36%). Among streptococci, group B streptococci were the most frequent (15%). The portal of entry was identified for 52% of hematogenous PJIs: 15% cutaneous, 11% dental, 9% gastrointestinal, 6% urinary, and 11% miscellaneous.

CONCLUSION

Although a wide variety of microorganisms was isolated from PJIs, specific microbiological patterns were observed according to infection classification.

Correlating pre-operative MRI measurements of metatarsal Osteomyelitis with surgical clean margins reveals the need for a one centimeter resection margin

Background

Due to the high incidence of forefoot ulcerations with associated osteomyelitis, there has been an increased demand for partial ray amputations. In order to ensure complete removal of infected metatarsal bone, a clean margin amount is chosen based on the surgeon’s intraoperative visual subjective evaluation. The margin is resected and sent to pathology. Currently the literature shows positive proximal margin rates of 35–40%. The purpose of this study was to reduce the rate of positive proximal margins by effectively resecting all infected bone using pre-operative MRI measurements with an added resection margin.

Methods

Twenty-four osteomyelitis positive metatarsals were included in this exploratory study. The distance of proximal osteomyelitic extension within the metatarsal was measured on MRI in centimeters. Intra-operatively, the partial ray amputation cut was determined by adding an extra 0.5 cm resection margin to the MRI measurement. At the study’s mid-point, bone histopathology revealed an increase in positive proximal margin rates-so the resection margin was increased to 1 cm. Descriptive outcomes included the mean distance of osteomyelitis propagation, proximal margin rates, as well as diagnostic statistics.

Results

After removing the specimens with false positive MRI results, the study sample included 21 metatarsals positive for osteomyelitis. A 0.5 cm resection margin proximal to the osteomyelitis resulted in a 50% positive proximal margin rate. After increasing the resection margin to 1 cm, there was found to be an improved positive proximal margin rate of 9%. Based on MRI findings, the mean distance + standard deviation of osteomyelitis propagation along the metatarsal proximally was 1.81 cm + 0.74 cm. The metatarsal specimen was processed by pathology into multiple pieces and compared to MRI, resulting in MRI sensitivity of 67%, specificity of 74%, positive predictive value of 79%, and negative predictive value of 60%.

Conclusions

By performing a 1 cm resection margin proximal to the metatarsal osteomyelitis the proximal margin rate was reduced to clinically meaningful levels. These preliminary findings support using a 1 cm resection margin when performing any form of metatarsal amputation, to reduce the risk of residual osteomyelitis post-operatively.

Trial registration

St. Luke’s Hospital, IRB National Protocol ID SLHN2015–112. Date:1–13-16.

Biofilm formation in total hip arthroplasty: prevention and treatment

This review assesses the current knowledge on treatments, pathogenesis and the prevention of infections associated with orthopaedic implants, with a focus on total hip arthroplasty.