Sonication in Patients With Spinal Cord Stimulation: A New Approach for Infection Diagnostics.

INTRODUCTION: Spinal cord stimulation (SCS) offers improvement in pain and function for several chronic pain conditions. There are concerns regarding bacterial colonization of the temporary lead extensions and subsequent infection risk in a two-session implantation procedure. Although there is no standardized evaluation of SCS lead contamination, this study evaluates the infection rate and microbial colonization of SCS lead extensions with sonication, a method that is established in implant-related infection diagnostics. MATERIALS AND METHODS: This prospective observational study comprised 32 patients with a two-stage SCS implantation procedure. Microbial colonization of the lead extensions was assessed with sonication. The presence of organisms in the subcutaneous tissue was evaluated separately. Surgical-site infections were recorded. Patient demographics and risk factors including diabetes, tobacco use, obesity, trial length, and infection parameters in serum were recorded and analyzed. RESULTS: The mean age of the patients was 55 years. On average, the trial length was 13 days. In seven cases (21.9%), a microbial lead colonization was found with sonication. In contrast, there was one positive culture (3.1%) from the subcutaneous tissue samples. The C-reactive protein and leukocyte count remained at the preoperative level. One early surgical-site infection (3.1%) occurred. No other late infections occurred six months after surgery. CONCLUSIONS: There is a discrepancy between the presence of microbial colonization and the occurrence of clinically relevant infections. Although the rate of microbial colonization of the lead extensions is high (21.9%), the surgical-site infection rate remained low (3.1%). Therefore, we can conclude that the two-session procedure is a safe approach that is not associated with a higher incidence of infection. Although the sonication method cannot be used as the sole tool for detecting infections in patients with SCS, it can provide additional value in microbial diagnostics in combination with clinical and laboratory parameters and conventional microbiological methods.

Increased rate of enteric bacteria as cause of periprosthetic joint infections in patients with liver cirrhosis.

INTRODUCTION: Periprosthetic joint infections (PJI) are a major complication in joint-arthroplasty. Rifampicin is often used as an additional agent to treat PJI, because it penetrates bacterial biofilms. However, rifaximin, belonging to the same antibiotic class as rifampicin, is frequently used to prevent episodes of hepatic encephalopathy in patients with cirrhosis and may induce resistance to rifampicin. The aim of this study was to examine the microbial pattern of periprosthetic joint infections in cirrhotic patients and to test the hypothesis that intake of rifaximin increases the rate of resistance to rifampicin in periprosthetic joint infections. METHODS: A cohort of cirrhotic patients and PJI (n = 25) was analysed on the characteristics of bacterial isolates from sonication and tissue analysis. In a second step a subgroup analysis on the development of rifampicin resistant bacterial specimens, depending on the intake of rifaximin (8 rifaximin intake patients vs. 13 non rifaximin intake patients) was performed. RESULTS: Intestinal bacteria were found in 50% of the specimens, which was significantly more frequent than in a control cohort. By comparison of the single bacterial isolates, rifampicin resistance was detected in 69.2% (9/13) of the rifaximin-intake samples. In contrast, the non-rifaximin-intake isolates only were resistant to rifampicin in 22.2% (4/18) of the cases (p = 0.01). The odds ratio for developing a rifampicin-resistance through rifaximin intake was calculated as OR = 13.5. CONCLUSION: Periprosthetic joint infections have a high incidence of being caused by enteric bacteria in cirrhotic patients. Due to this change in microbial pattern and the innate resistance to rifampicin of most of gram-negative bacteria, the therapy with rifampicin should be carefully considered. The association between the use of rifaximin and developed resistance to rifampicin has a major impact on the treatment of PJI.

The Influence of Iodine-Impregnated Incision Drapes on the Bacterial Contamination of Scalpel Blades in Joint Arthroplasty.

BACKGROUND: Prosthetic joint infections (PJI) are a disastrous and feared complication in arthroplasty. Over the past decades, surgeons have tried to lower infection rates through all sorts of improvements. At present, it is impossible to reduce the risk to zero. As the contamination of surgical instruments and the surgical field has been identified as a remaining gap prone for infection, scalpel blades among others have become a focal point of several studies. This study is the first to compare the effect of adhesive incision drapes on contamination rates of scalpel blades in primary arthroplasty of the hip and knee. METHODS: A total of 344 microbiologic blade culture results from 2 study groups with and without drape usage and 1 group with known PJI were analyzed and compared to histopathologic and microbiologic tissue results. RESULTS: In 78% of all positive cultures, the bacteria were part of the local skin flora. The contamination rate for the skin blades with a drape was 3.81% vs 12.19% without drape usage. A significant difference was determined between positive skin blade culture results incision drape usage (P = .031). The different pathogens likely responsible for the PJI correlated with the deep blade cultures (P ≤ .01). The overall contamination rate of surgical blades (1.37%) is comparatively low to the results obtained from other surgical equipment in literature. None of those blade-positive patients developed a surgical site infection during 12-month follow-up. CONCLUSION: Iodine-impregnated incision drapes are able to reduce surgical skin blade contamination. Further studies may be needed to assess the relationship between blade contamination and surgical site infections.

Recurrent mucocutaneous infections caused by PVL-positive Staphylococcus aureus strains: a challenge in clinical practice.

BACKGROUND: Recurrent mucocutaneous infections caused by PVL-positive Staphylococcus (S.) aureus strains represent an increasing problem in Germany. Although there have been several outbreaks at day care centers and in urban communities in recent years, there are currently no diagnostic algorithms or treatment recommendations for these particular infections in Germany. METHODS: We performed a literature search in the PubMed/MEDLINE database with the goal of developing an algorithm for diagnosis and treatment of these infections. National and international recommendations were also considered. RESULTS: Panton-Valentine leukocidin (PVL) is a pore-forming protein produced by certain S. aureus strains. Both methicillin-susceptible (MSSA) and methicillin-resistant S. aureus (MRSA) strains may carry the lukS-lukF gene responsible for PVL production. The clinical presentation of infections caused by PVL-positive S. aureus ranges from isolated recurrent abscesses to extensive furunculosis. Despite adequate treatment of primary infections, approximately 40 % of patients develop recurrent disease. The choice of treatment regimen is guided by the clinical presentation of the infection. In addition, some scientific literature recommends bacteriological screening of patients and their contacts, followed by decolonization of affected individuals. CONCLUSIONS: The present article focuses on the pathogenesis and risk factors of recurrent mucocutaneous infections caused by PVL-positive S. aureus strains and proposes a diagnostic and therapeutic algorithm for optimal patient care.

Detection of methicillin-resistant coagulase-negative staphylococci harboring the class A mec complex by MALDI-TOF mass spectrometry.

The aim of this study was to test the identification of methicillin resistance in coagulase-negative staphylococci by routine matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS). SCCmec cassettes of type II, III and VIII encode a small peptide called PSM-mec in the vicinity of mecA. It is visible at m/z 2415 during MALDI-TOF MS of whole cells of Staphylococcus aureus. In view of the fact that psm-mec has been identified in methicillin-resistant coagulase-negative staphylococci, we evaluated a collection of clinical coagulase-negative staphylococci, that contained 77.03% of methicillin-resistant isolates, for the presence of the structural gene encoding PSM-mec and the appearance of the corresponding signal during mass spectroscopy. In MALDI-TOF MS spectra, 89.65% of the strains that harbored the gene yielded the correct signal, corresponding to a sensitivity of 0.897 and a specificity of 1.0. However, regarding detection of methicillin resistance, i. e. considering all resistant strains as positive regardless of the presence of the gene, the overall sensitivity of the test decreased to 0.285, due to the fact that only 29.43% of all resistant isolates contained psm-mec. In conclusion, the presence of the signal in MALDI-TOF MS quickly indicates methicillin-resistance in coagulase-negative staphylococci but its absence does not indicate susceptibility to methicillin.

Successful Therapy of a Multidrug-Resistant Extended-Spectrum ß-Lactamase-Producing and Fluoroquinolone-Resistant Salmonella enterica Subspecies enterica Serovar Typhi Infection Using Combination Therapy of Meropenem and Fosfomycin.

We report a traveler who acquired a Salmonella enterica subspecies enterica serovar Typhi strain with resistance against ß-lactams, cephalosporins (extended-spectrum ß-lactamase-producing type SHV-12), and quinolones (plasmid-mediated quinolone resistance gene qnrB7). After clinical deterioration using meropenem monotherapy, treatment success was achieved after commencement of fosfomycin in conjunction with high-dose meropenem. The case illustrates clinical challenges of multidrug-resistant S. Typhi.

Polymicrobial infections reduce the cure rate in prosthetic joint infections: outcome analysis with two-stage exchange and follow-up ≥two years.

PURPOSE: Prosthetic joint infections (PJI) are a serious and challenging complication after total joint arthroplasty. According to the literature, most PJI are monomicrobial infections caused by gram-positive cocci. The number of polymicrobial PJI might be underrepresented in the literature and only limited data are available regarding the outcome of polymicrobial PJI. Our hypothesis was that polymicrobial PJI are associated with a reduced cure rate compared with monomicrobial PJI. METHODS: Routine clinical data were collected and analysed retrospectively as anonymised, aggregated data. A total of 77 consecutive patients with 77 confirmed PJI and proven infectious organism of the hip and knee joint treated within a two-stage exchange concept and a follow-up ≥ two years were investigated. Detection of the infectious organism was based on multiple microbiological cultures taken intra-operatively. Superficial wound swabs or swabs from sinus tracts were not taken into account. Data were grouped into polymicrobial and monomicrobial PJI. The main outcome variable was "definitively free of infection after two years" as published. Second, we considered several variables as potential confounders or as risk factors. RESULTS: A total of 42 men and 35 women with 46 infected total hip arthroplasties and 31 infected total knee arthroplasties were evaluated. In 37 (46.6 %) of our 77 patients a polymicrobial PJI could be detected. We found a significant association between polymicrobial PJI and the outcome parameter definitively free of infection after two years with an odds ratio (OR) of 0.3 [95 % confidence interval (CI) 0.1-1.0]. The rate of patients graded as definitively free of infection after two years was 67.6 % for polymicrobial infections vs. 87.5 % for monomicrobial infections. The American Society of Anesthesiologists (ASA) score (OR 0.4, 95 % CI 0.2-1.0, p = 0.062) was identified as a borderline significant covariable. CONCLUSIONS: Our data suggest that polymicrobial PJI might be underrepresented in the current literature. Additionally, the presence of multiple infectious organisms is associated with a reduced rate after two years with 67.6 vs 87.5 % for monomicrobial infections. Special attention and extra care should be considered for these patients.

Evidence of MRSE on a gentamicin and vancomycin impregnated polymethyl-methacrylate (PMMA) bone cement spacer after two-stage exchange arthroplasty due to periprosthetic joint infection of the knee.

BACKGROUND: Periprosthetic joint infections (PJI) are often treated by two stage exchange with the use of an antibiotic impregnated spacer. Most of the two-stage exchange algorithms recommend the implantation of an antibiotic-impregnated spacer during the first stage for a period of 2-24 weeks before reimplantation of the new prosthesis. For the spacer to have a therapeutic effect, the local antibiotic concentration must be greater than the minimal inhibition concentration (MIC) against the pathogens causing the PJI. It must remain so for the entire spacer period, otherwise recurrence of infection or resistances might occur. The question as to whether a sufficient concentration of antibiotics in vivo is reached for the entire spacer period has not been answered satisfactorily. CASE PRESENTATION: We here present a case of a histologically confirmed chronic PJI 20 month after primary arthroplasty. The primary knee arthroplasty was performed due to osteoarthritis of the joint. Initial assessment did not detect a causative pathogen, and two stage exchange with a vancomycin-gentamycin impregnated spacer was performed. At the time of reimplantation, sonication of the explanted spacer revealed a multi-resistant strain of staphylococcus epidermidis on the device and in the joint. Adaption of the therapy and prolonged treatment successfully eradicated the infection. CONCLUSION: According to the authors' knowledge, the case presented here confirms for the first time the surface contamination (proven through sonication) of a vancomycin-/gentamicin- impregnated Vancogenx®-spacer with a MRSE after ten weeks of implantation.This case study demonstrates the difficulties still associated with the diagnostics of PJI and the published different two stage treatment regimes with the use of antibiotic impregnated spacers.

Microbiological Profiles of Patients with Spondylodiscitis.

Spondylodiscitis is a severe spinal infection that requires an effective antibiotic treatment. Therefore, we sought to analyse the causative pathogens from intraoperative specimen in patients with spondylodiscitis and a need for surgery. To this end, we performed a retrospective study of all patients with spondylodiscitis and a need for operative treatment admitted to our hospital between January 2020 and December 2022. A total of 114 cases with spondylodiscitis were identified. A total of 120 different pathogens were detected. Overall, 76.7% of those microorganisms were Gram-positive bacteria. The most common causative pathogen was Staphylococcus aureus (n = 32; 26.6%), followed by coagulase-negative staphylococci (n = 28; 23.4%), of which Staphylococcus epidermidis (n = 18; 15%) was the most frequently detected, as well as enterococci (n = 10; 8.4%) and Streptococcus spp. (n = 11; 9.2%). Moreover, 19.1% (n = 22) and 3.4% (n = 4) of all detected isolates were Gram-negative pathogens or fungi, respectively. Overall, 42.8% of all coagulase-negative staphylococci were oxacillin-resistant, while none of them were vancomycin-resistant. In summary, 50% of the pathogens could be identified as staphylococci. The results of our study highlight the important burden of oxacillin-resistant Gram-positive bacteria as an aetiological cause of spondylodiscitis, providing a relevant finding for antimicrobial stewardship programmes.

Prevalence and prognostic relevance of invasive fungal disease during veno-arterial ECMO: A retrospective single-center study.

PURPOSE: To assess the prevalence and relevance of invasive fungal disease (IFD) during veno-arterial (V-A) extracorporeal membrane oxygenation (ECMO). METHODS: Retrospective analysis from January 2013 to November 2023 of adult V-A ECMO cases at a German University Hospital. Parameters relating to IFD, demographics, length of stay (LoS), days on ECMO and mechanical ventilation, prognostic scores and survival were assessed. Multivariable logistic regression analyses with IFD and death as dependent variables were performed. Outcome was assessed after propensity score matching IFD-patients to non-IFD-controls. RESULTS: 421 patients received V-A ECMO. 392 patients with full electronic datasets were included. The prevalence of IFD, invasive candidiasis and probable invasive pulmonary aspergillosis was 4.6%, 3.8% and 1.0%. Severity of acute disease, pre-existing moderate-to-severe renal disease and continuous kidney replacement therapy were predictive of IFD. In-hospital mortality (94% (17/18) compared to 67% (252/374) in non-IFD patients (p = 0.0156)) was predicted by female sex, SOFA score at admission, SAVE score and IFD (for IFD: OR: 8.31; CI: 1.60-153.18; p: 0.044). There was no difference in outcome after matching IFD-cases to non-IFD-controls. CONCLUSIONS: IFD are detected in about one in 20 patients on V-A ECMO, indicating mortality >90%. However, IFD do not contribute to prognosis in this population.

Description of Standardized Planes and Angles for Percutaneous Supra-acetabular Screw Placement.

BACKGROUND: Percutaneous screw fixation for pelvic fractures has become a minimally invasive alternative to an open operation. The complex anatomy of the pelvis renders this procedure challenging. The objective of this study was to assess standardized angles and dimensions of safety zones within a 3 D computed tomography model for optimal supra-acetabular screw placement. METHODS: Computed tomography scans of 107 patients that suffered major trauma without showing any bone injury of the pelvis were collected. Using a software-based analysis, raw computed tomography data were transformed into 3 D models to set standardized landmarks and determine the possible insertion corridor. RESULTS: Screws not exceeding a length of 97 mm in females and 106.4 mm in males were, in 95% of the evaluated cases, insertable without cortical bone penetration. The safety zone was 6.6 mm for females and 7.9 mm for males. Screws not exceeding these diameters were safely insertable in 95% of the cases. For the midsagittal plane, the angle was 36.4 ± 5.1 on the left and 34.7 ± 2.9 on the right (p = 0.008). For the anterior pelvic plane, the angle was 31.3 ± 4.5° on the left and 34.0 ± 4.8° on the right (p = 0.008). CONCLUSIONS: Percutaneous fixation using supra-acetabular screws is a promising method to treat simple supra-acetabular fractures. These results may improve its safe utilization and could facilitate its broader clinical application.

Periprosthetic joint infection caused by kytococcus schroeteri: The first reported case and a review of the literature.

Oftentimes, Gram-positive cocci are the cause for periprosthetic joint infections (PJI). Most of these infections include bacteria such as Staphylococcus aureus, Staphylococcus epidermidis or other coagulase-negative staphylococci. We here present the first case of a PJI caused by Kytococcus schroeteri. While being a Gram-positive coccus, it is very rarely the cause for infections in the human body. K. schroeteri is part of the micrococcus branch and often encountered as a symbiotic bacterium living on the skin. Regarding its pathogenic potential, not a lot is known since less than a few dozen human infections have been reported worldwide. Furthermore, many of the cases reported are either associated with implanted material, especially heart valves, or associated with patients whose immune response is deficient. Only 3 reports of osteoarticular infections are described so far.

Microbiological Trends and Antibiotic Susceptibility Patterns in Patients with Periprosthetic Joint Infection of the Hip or Knee over 6 Years.

We sought to analyze trends of the causative pathogens and their antibiotic susceptibility patterns in patients with periprosthetic joint infections (PJI) of the hip and knee to get better insights and improve treatment. Retrospective evaluation of all consecutive patients with microbiological detection of a causative pathogen at a tertiary endoprothetic referral center between January 2016 and December 2021 in Germany was performed. Overall, 612 different microorganisms could be detected in 493 patients (hip: n = 293; knee: n = 200). Evaluation did not show a change in the relative abundance of pathogens detected, with coagulase-negative staphylococci (n = 275; 44.9%) found frequently, followed by S. aureus (n = 86; 14.1%), Enterococcus species (n = 57; 9.3%), Streptococcus species (n = 48; 7.8%), and Gram-negative bacteria (n = 80; 13.1%). Evaluation of the antibiotic susceptibilities showed increasing rates of oxacillin-resistant coagulase-negative staphylococci (60.4%; 46.8−76.7%) and piperacillin-tazobactam-resistant Gram-negative bacteria (26.5%; 0−57.1%), although statistically not significant. Resistance of Gram-positive bacteria to vancomycin (<1%) and Gram-negative microorganisms to meropenem (1.25%) remained an exception. In summary, coagulase-negative staphylococci, as the most frequent pathogen, displayed a continuously high rate of oxacillin resistance. For the highest antimicrobial coverage in the case of an empiric therapy/unknown pathogen, vancomycin might be chosen. Level of evidence: IV.

Microbiological Profiles of Patients with Periprosthetic Joint Infection of the Hip or Knee.

Periprosthetic joint infections (PJI) are one of the most devastating consequences after total joint arthroplasty. We sought to analyze the causative pathogens of patients with PJI to get better insights and improve treatment. We performed a retrospective study of all patients with PJI of the hip and knee with microbiological detection of a causative pathogen at a tertiary endoprothetic referral center between January 2016 and March 2021. A total of 432 cases with PJI (hip: n = 250; knee: n = 182) were included. The most common causative pathogen were coagulase-negative staphylococci (n = 240; 44.2%), of which Staphylococcus epidermidis (n = 144; 26.7%) was the most frequently detected, followed by S. aureus (n = 77; 14.3%) and enterococci (n = 49; 9%). Gram-negative pathogens and fungi could be detected in 21% (n = 136) and 2.4% (n = 13) of all cases. Overall, 60% of all coagulase-negative staphylococci were oxacillin-resistant, while none of these displayed to be vancomycin-resistant. In summary, the majority of pathogens in cases of PJI could be identified as coagulase-negative staphylococci. For empirical therapy vancomycin might provide the highest antimicrobial coverage in case of an unknown pathogen.

The psychological burden of a two-stage exchange of infected total hip and knee arthroplasties.

Infection is one of the most challenging complications after total joint arthroplasties affecting up to 30,000 patients in the US per year. This study investigates the psycho-social burden induced by the two-stage intervention in infected hip or knee replacements. All patients were treated with a two-stage exchange and were assessed at three different timepoints regarding their psychological conditions. Our findings suggest that psychological sequelae after treatment of periprosthetic joint infection are clearly underestimated in the literature and psychological correlates and side effects should be further highlighted during the training process of young surgeons.