Septic hip abscess due to Fusobacterium nucleatum and Actinomyces turicensis in an immunocompetent SARS-CoV-2 positive patient.

A 42-year-old man was referred to the Department of Orthopedic Surgery with pain over his right greater trochanter and signs of systemic infection. CT showed an enhanced mass in his gluteus maximus as well as gas in the biceps femoris over the underlying hip joint. Tissue biopsy yielded Fusobacterium nucleatum and Actinomyces turicensis. The patient was successfully treated for 6 weeks with amoxicillin/clavulanic acid 875mg/125mg and metronidazole 500mg.

Ruling out underlying infection in 200 presumed aseptic knee and hip revision arthroplasties using a multiplex PCR system.

Ruling out an infection in one-stage knee and hip revisions for presumed aseptic failure by conventional tissue cultures takes up to 14 days. Multiplex polymerase chain reaction (mPCR) is a quick test (4-5 h) for detecting pathogens. The purpose of this study was to evaluate the diagnostic accuracy of an automated mPCR of synovial fluid obtained intraoperatively in unsuspected knee and hip revisions. A prospective study was conducted with 200 patients undergoing a one-stage knee or hip revision. Synovial fluid was analyzed with the mPCR Unyvero implant and tissue infection G2 cartridge (U-ITI G2) system and compared to intraoperative tissue cultures. The primary outcome measure was the diagnostic accuracy, including sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), of the mPCR U-ITI G2 system compared to conventional cultures. In the knee revision group, there were no patients with a positive mPCR in combination with positive cultures. This resulted in a non-calculable sensitivity and PPV. The specificity and NPV in the knee revision group of the mPCR compared to tissue cultures was 96.8% and 96.8%, respectively. In the hip revision group, the sensitivity, specificity, PPV, and NPV of the mPCR compared to tissue cultures was 36.4%, 96.6%, 57.1%, and 92.5%, respectively. Sixteen mismatches occurred between the mPCR and tissue cultures. The mPCR U-ITI G2 system is a quick and reliable synovium fluid test for ruling out infection in presumed aseptic knee and hip revisions with a high NPV compared with tissue cultures, although some mismatches were observed. Periprosthetic tissue cultures are still advised as back-up for false negative and positive mPCR test results.

Cutibacterium colonization of the anterior and lateral thigh.

AIMS: Of growing concern in arthroplasty is the emergence of atypical infections, particularly Cutibacterium (formerly Propionibacterium) sp. infections. Currently, the dermal colonization rate of Cutibacterium about the hip is unknown. Therefore, the aim of this study was to investigate colonization rates of Cutibacterium sp. at locations approximating anterior and posterolateral approaches to the hip joint. METHODS: For this non-randomized non-blinded study, 101 adult patients scheduled for hip or knee surgery were recruited. For each, four 3 mm dermal punch biopsies were collected after administration of anaesthesia, but prior to antibiotics. Prebiopsy skin preparation consisted of a standardized preoperative 2% chlorhexidine skin cleansing protocol and an additional 70% isopropyl alcohol mechanical skin scrub immediately prior to biopsy collection. Two skin samples 10 cm apart were collected from a location approximating a standard direct anterior skin incision, and two samples 10 cm apart were collected from a lateral skin incision (suitable for posterior, direct-lateral, or anterolateral approaches). Samples were cultured for two weeks using a protocol optimized for Cutibacterium. RESULTS: A total of 23 out of 404 cultures (collected from 101 patients) were positive for a microorganism, with a total of 22 patients having a positive culture (22%). Overall, 15 of the cultures in 14 patients were positive for Cutibacterium sp. (65%), of which Cutibacterium acnes comprised the majority (n = 13; 87%). Other isolated microorganisms include coagulase-negative Staphylococcus (n = 6), Clostridium (n = 1), and Corynebacterium (n = 1). Of all positive cultures, 15 were obtained from the anterior location (65%), of which seven (60%) were from the most proximal biopsy location. However, these findings were not statistically significant (anterior vs lateral, p = 0.076; proximal vs distal, p =0.238). CONCLUSION: Approximately 14% (14/101) of the patients demonstrated a positive Cutibacterium colonization about the hip, the majority anteriorly. Given the high colonization rate of Cutibacterium, alternative skin preparations for total hip arthroplasty should be considered. Cite this article: Bone Joint J 2020;102-B(7 Supple B):52-56.

Periprosthetic joint infection in aseptic total hip arthroplasty revision.

PURPOSE: There is no consensus regarding systematic screening for infection in aseptic revision total hip arthroplasty (THA). The rationale for systematic intra-operative samples is to increase the sensitivity of latent infections detection, which may require specific treatment. However, the incidence of occult infection in revision THAs is not precisely known. As such, the aim of the study was to evaluate the incidence of occult infection in presumed aseptic revision THAs and identify associated risk factors. METHOD: Bacteriological samples from 523 aseptic THA revisions performed for five years were analyzed. Revisions performed for periprosthetic joint infection (PJI) or clinical suspicion of PJI were excluded. Microbiological cultures were performed using tissue samples in 505 cases (97%), synovial fluid in blood culture vials in 158 (30%), and in dry tubes in 263 (50%). Implants were sent for sonication in 12 cases (2.6%). The mean number of microbiological samples per patient was 3.6 (range, 1-15). Histology samples were collected for 300 patients (57%). RESULTS: The incidence of occult infection was 7% (36 cases) and contamination 8% (42 cases). Among occult infections, the primary reasons for revision were dislocation (42%), aseptic loosening (25%), fracture (19%), and others (14%). The infection rate in the dislocation group was significantly higher than that of other reasons for revision (p < 0.001). Among the patients determined with PJI, the revision THA was performed less than a year after primary in 19 (53%). CONCLUSION: The incidence of occult PJI justifies systematic intraoperative sampling. A short time between primary arthroplasty and revision or an early postoperative dislocation is a factor to suspect infections.

A Patient with Pediatric Septic Arthritis of the Hip Complicated with Osteomyelitis Responds to Clindamycin.

A 5-year-old girl was referred to our institution with complaints of right hip pain and fever (39.0°C); blood tests and magnetic resonance imaging (MRI) were performed. Blood biochemical results revealed a high inflammatory reaction. MRI results revealed inflammation in the hip joint. She was diagnosed with pediatric septic arthritis of the hip, which required arthrotomy and lavage drainage. Treatment with intravenous vancomycin was initiated on the assumption that the causative bacterial species was Staphylococcus aureus. However, Group A Streptococcus pyogenes (GAS) was subsequently isolated from an intraoperative sample, and the antimicrobial agent was switched to aminobenzylpenicillin (ABPC). Clindamycin (CLDM) was added to the treatment regimen 14 days after surgery as MRI indicated the development and spread of osteomyelitis. Three months post-surgery, MRI findings indicated that the osteomyelitis had resolved and antimicrobial therapy was discontinued. To prevent the spread of osteomyelitis, a combination of CLDM and ABPC should be considered at an early stage, particularly in pediatric patients with GAS-induced septic arthritis.

Slackia exigua, an anaerobic Gram-positive rod and part of human oral microbiota associated with periprosthetic joint infection of the hip. First case and review of the literature.

We report on the first case of a periprosthetic joint infection with the anaerobic Gram-positive rod Slackia exigua as the causative agent. The bacterium is part of human oral microbiota and has so far mainly been associated with periodontal diseases.

Can a Septic Hip Decision Rule Aid in the Evaluation of Suspected Pediatric Musculoskeletal Infections?

BACKGROUND: Musculoskeletal (MSK) infections can be difficult to diagnose in acute care settings. The utility of clinical decision tools for pediatric MSK infections in an emergency department has not been well studied. OBJECTIVE: Our aim was to evaluate the performance of a septic hip clinical decision rule (CDR) in the evaluation of pediatric musculoskeletal infections. METHODS: We performed a retrospective study of children evaluated for an MSK infection in our emergency department from 2014 to 2016. Data collection included demographics, discharge diagnoses, and clinical/laboratory predictors from the CDR. A χ2 analysis and Wilcoxon rank-sum tests compared patients with and without MSK infections. Logistic regression analysis examined the predictors for MSK infections. A receiver operating characteristic (ROC) curve was calculated to evaluate the performance of the predictors. RESULTS: Of 996 evaluations included in the final analysis, 109 (10.9%) had MSK infections. In a multivariable model, an adjusted odds ratio (OR) was significant for fever (OR 3.9, 95% confidence interval [CI] 2.4-6.4), refusal to bear weight/pseudoparalysis (OR 4.4, 95% CI 2.7-7.1), and C-reactive protein (CRP) > 2.0 mg/dL (OR 5.4, 95% CI 3.2-9.1). The probability of infection was 75.1% with five predictors present, 1.9% for zero predictors, and 5.1% if one predictor was present. An ROC curve showed an area under the curve of 0.82, indicating moderate accuracy. CONCLUSIONS: A septic hip CDR demonstrates a low predicted probability of an MSK infection with zero or one clinical predictor present and moderate predictability with all five predictors. Fever, refusal to bear weight/pseudoparalysis, and CRP > 2.0 mg/dL performed best and should alert providers to consider other MSK infections in addition to septic arthritis.

Is it safe to do a single-stage implant exit and primary hip replacement? clinical and microbiological profiling.

Background: A single-stage implant revision for failed fixation of proximal femoral fractures is performed only when there is no evidence of infection. Else, a two-staged revision is preferred - where the definitive revision surgery is done a few months after the implant exit. This study aims to audit the safety and incidence of culture positivity in single-stage revisions. Materials and Methods: Forty one of 284 patients that presented over the last 12 years for implant exchange of the hip, had a single stage revision surgery for failed fixation of a fracture of the hip, as there was no obvious evidence of infection at the time of implant exit. Results: Micro-organisms were grown in 51% of the 41 hips. 76% were gram positive, of which 63% were Coagulase negative staphylococci (CoNS). 50% of CoNS and 75% of S. aureus were resistant to oxacillin, but susceptible to Vancomycin. Of the gram negative organisms, 2 (Enterobacter sp) were resistant to carbapenam, while others were susceptible. Preoperative ESR and CRP, individually, had low specificity - 50% for ESR >30mm at 1 hour and 62% for CRP>10. The combined use of ESR > 30mm and CRP>10 increased the specificity to 90%. 12% of the patients had immediate postoperative complications that required a wash out in theatre. The long term clinical follow up of these patients is limited. Conclusion: This study suggests that implant exit and simultaneous arthroplasty for failed fracture fixation should be done with caution due to the high possibility of infection. It may be prudent to opt for a 2 stage revision.

Point-of-Care Ultrasound Identification of a Psoas Abscess in a Child Presenting With Hip Pain.

This case-report describes a 4-year-old girl brought to the emergency department for the evaluation of limp and elevated inflammatory markers. The patient's history and physical examination did not reveal a clear source of pathology. Point-of-care ultrasound identified a right-sided psoas abscess that was confirmed with computed tomography scan. This case demonstrates the potential utility of point-of-care ultrasound in the diagnosis and management of patients presenting to the emergency department with symptoms concerning for pathology in the hip or lower abdomen.

Unilateral infective sacroiliitis in a boy presenting with a limp.

A 9-year-old boy admitted to a district general hospital with a 1-week history of fever and a 2-day history of right hip pain. Initial workup revealed raised inflammatory markers and unremarkable imaging studies. After clinical review, there was minimal improvement of the patient's condition 5 days after presentation; therefore, an MRI of the pelvis/hips was carried out, which supported a clinical diagnosis of right-sided infective sacroiliitis. Infective sacroiliitis is rare and only represents 1%-2% of septic arthritis in children. The condition still remains a diagnostic challenge first due to poor localisation of symptoms with referred pain to the hip, thigh and lower back and second due to a lack of awareness by non-specialist clinicians. Early diagnosis is a key to avoid sequelae such as an abscess, degenerative changes of the sacroiliac joint and can be achieved by a thorough clinical examination, monitoring inflammatory markers and MRI.

Mycobacterium bovis hip bursitis in a lung transplant recipient.

We present a report of extrapulmonary Mycobacterium bovis infection in a lung transplant recipient. M. bovis is acquired predominantly by zoonotic transmission, particularly from consumption of unpasteurized foods. We discuss epidemiologic exposure, especially as relates to the Mexico-US border, clinical characteristics, resistance profile, and treatment.

Identification of a Novel Mycoplasma Species in a Patient With Septic Arthritis of the Hip and Seal Finger.

An Alaska Native hunter developed fever, swollen finger, and septic hips after harvesting seals. Evaluation of hip tissue by 16S rRNA gene polymerase chain reaction and sequencing revealed a putative novel mycoplasma species. We report the identification of this organism and describe the first known case of disseminated seal finger mycoplasmosis.

In Vitro Activity of Imipenem and Colistin against a Carbapenem-Resistant Klebsiella pneumoniae Isolate Coproducing SHV-31, CMY-2, and DHA-1.

We investigated the synergism of colistin and imipenem against a multidrug-resistant K. pneumoniae isolate which was recovered from a severe hip infection. PCR and DNA sequencing were used to characterize the outer membrane porin genes and the resistance genes mediating the common ß-lactamases and carbapenemases. Synergism was evaluated by time-kill studies. The bla SHV-31, bla CMY-2, and bla DHA-1 were detected. Outer membrane porin genes analysis revealed loss of ompK36 and frame-shift mutation of ompK35. The common carbapenemase genes were not found. Time-kill studies demonstrated that a combination of 1x MIC of colistin (2 mg/L) and 1x MIC of imipenem (8 mg/L) was synergistic and bactericidal but with inoculum effect. Bactericidal activity without inoculum effect was observed by concentration of 2x MIC of colistin alone or plus 2x MIC of imipenem. In conclusion, colistin plus imipenem could be an alternative option to treat carbapenem-resistant K. pneumoniae infections.

Systemic review of published literature on Candida infection following total hip arthroplasty.

Candida species (Candida spp.) infection following total hip arthroplasty (THA) is a rare but potentially devastating complication. The purpose of this study was to provide an evidence-based summarization of the treatment and outcome of Candida spp. infection after THA. We conducted a systemic review of the literature and pooled analysis of Candida spp. infection after THA published between 1950 and 2014. A total of 20 articles with 37 patients were identified. Median time between THA and readmission for Candida spp. infection was 25 months (range 0.5-184 months). Thirty-two patients (87%) underwent removal of the prosthesis for initial surgical treatment. All patients were treated with systemic antifungal medication therapy for various durations after the surgical procedure or primary therapy without surgical procedures except for one patient who was treated with only amphotericin B joint cavity irrigation after removal of the prosthesis. Relapse of the infection occurred in three patients who had retention of the original prosthesis. There were three deaths related to the Candida spp. infection following THA owing to uncontrolled Candida spp. infection and deteriorating candidemia sepsis. Of note, among 15 patients who underwent two-stage exchange arthroplasty, there was one patient (7%) who developed complication (death) while other 14 patients had uncomplicated recovery. In conclusion, surgical debridement with removal of the original prosthesis or two-stage exchange arthroplasty with combination of adequate systemic antifungal therapy is highly recommended in the treatment of Candida spp. infection following THA.

Medial approach for drainage of the obturator musculature in children.

BACKGROUND: In a recent study designed to determine the anatomic location of infection in children presenting with acute hip pain, fever, and elevated inflammatory markers, we demonstrated the incidence of infection of the musculature surrounding the hip to be greater than twice that of septic arthritis. Importantly, the obturator musculature was infected in >60% of cases. Situated deep in the pelvis, surrounding the obturator foramen, debridement of these muscles and placement of a drain traditionally requires an extensive ilioinguinal or Pfannenstiel approach, placing significant risk to the surrounding neurovascular structures. We hypothesized that the obturator internus and externus could be successfully debrided using a limited medial approach. METHODS: An IRB-approved prospective study of children (0 to 18 y) evaluated in the pediatric emergency department by an orthopaedic surgeon to rule out septic hip arthritis at a tertiary care children's hospital (July 1, 2010 to June 30, 2012) was conducted. Infected obturator musculature was identified and confirmed using magnetic resonance imaging. Cadaveric dissection was performed comparing the ilioinguinal, Pfannenstiel, and proposed minimally invasive medial approach. The proposed approach was utilized to debride and place drains in 7 consecutive patients. RESULTS: Anatomic information gained from magnetic resonance images of patients with abscess within the obturator musculature, and from the results of cadaveric studies, allowed for planning of a novel surgical approach. We found that through the surgical approach used to perform an osteotomy of the ischium (Tonnis) the obturator externus could be debrided through the adductor brevis and the obturator internus could be debrided through the obturator foramen. Using our medial approach, resolution of symptoms in all children who underwent surgical drainage resulted without complication. CONCLUSIONS: Our medial approach can safely access the obturator musculature for abscess decompression and drain placement with successful results. Advantages to this approach include: lower risk to neurovascular structures within the pelvis, less soft tissue trauma, and similarity to current techniques used for adductor lengthening, medial reduction of the dislocated hip, and osteotomy of the ischium. LEVEL OF EVIDENCE: Level II.

Indoleamine 2,3-dioxygenase activity as a potential biomarker of immune suppression during visceral leishmaniasis.

Leishmania parasites induce an immunomodulation by subverting the host immune response towards a CD4(+) Th2 lymphocytic cell response that favors parasite persistence. Here, we report that after successful treatment of visceral leishmaniasis due to Leishmania infantum, an immune reconstitution syndrome revealing hip septic arthritis was associated with a switch from Th2 towards a Th1 cytokine profile, and a decrease in the level of immunomodulating factors, such as soluble HLA-G and indoleamine 2,3-dioxygenase (IDO) activity. We then measured IDO activity in a cohort of 39 patients and uninfected control subjects. Results showed significantly enhanced IDO activity in patients with visceral Leishmania infection, compared with uninfected control subjects (P < 0.001), but also compared with treated patients (P < 0.05). A decrease in IDO activity could constitute a relevant biomarker for the restoration of the immune response during visceral leishmaniasis.

Microbiological aetiology, epidemiology, and clinical profile of prosthetic joint infections: are current antibiotic prophylaxis guidelines effective?

Prosthetic joint infections remain a major complication of arthroplasty. At present, local and international guidelines recommend cefazolin as a surgical antibiotic prophylaxis at the time of arthroplasty. This retrospective cohort study conducted across 10 hospitals over a 3-year period (January 2006 to December 2008) investigated the epidemiology and microbiological etiology of prosthetic joint infections. There were 163 cases of prosthetic joint infection identified. From a review of the microbiological culture results, methicillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative staphylococci were isolated in 45% of infections. In addition, polymicrobial infections, particularly those involving Gram-negative bacilli and enterococcal species, were common (36%). The majority (88%) of patients received cefazolin as an antibiotic prophylaxis at the time of arthroplasty. In 63% of patients in this cohort, the microorganisms subsequently obtained were not susceptible to the antibiotic prophylaxis administered. The results of this study highlight the importance of ongoing reviews of the local ecology of prosthetic joint infection, demonstrating that the spectrum of pathogens involved is broad. The results should inform empirical antibiotic therapy. This report also provokes discussion about infection control strategies, including changing surgical antibiotic prophylaxis to a combination of glycopeptide and cefazolin, to reduce the incidence of infections due to methicillin-resistant staphylococci.

Rapid, progressive neuropathic arthropathy of the hip in a patient co-infected with human immunodeficiency virus, hepatitis C virus and tertiary syphilis: case report.

BACKGROUND: Syphilis is a chronic infection that is classified into three stages. In its tertiary stage, syphilis spreads to the brain, heart and other organs; the lesions may involve the skin, mucous membranes and bones. Neuropathic arthropathy associated with tertiary syphilis has rarely been described in Europe and its association with HIV-HCV co-infection has not been reported so far.This article reports the case of a man with tertiary syphilis presenting with rapidly evolving neuropathic arthropathy of the hip and extensive bone destruction. CASE PRESENTATION: On initial presentation, the patient complained of progressively worsening left-sided coxalgia without localized or generalized inflammation. The patient reported to have no history of previous infections, trauma or cancer. Plain x-ray films of the left coxofemoral joint showed marked degeneration with necrosis of the proximal epiphysis of femur and morphological alterations of the acetabulum without protrusion. Primary coxarthrosis was diagnosed and hip arthroplasty was offered, but the patient declined treatment. Three months later, the patient presented a marked deterioration of his general condition. He disclosed that he was seropositive for HCV and HIV, as confirmed by serology. Syphilis serology testing was also positive. A Girdlestone's procedure was performed and samples were collected for routine cultures for bacteria and acid fast bacilli, all resulting negative.Although histological findings were inconclusive, confirmed positive serology for syphilis associated with progressive arthropathy was strongly suggestive of tertiary syphilis, probably exacerbated by HIV-HCV co-infection. The patient partially recovered the ability to walk. CONCLUSIONS: Due to the resurgence of syphilis, this disease should be considered as a possible cause of neuropathic arthropathy when other infectious causes have been ruled out, particularly in patients with HIV and/or HCV co-infection.