Can we rely on histopathological results for the diagnosis of prosthetic joint infection?

BACKGROUND: Histopathology is one of the diagnostic criteria for prosthetic joint infection (PJI) proposed by all academic societies. The aim of this study was to compare histopathological and microbiological results from samples taken intraoperatively at the same site in patients with suspected or proven PJI. PATIENTS AND METHODS: We conducted a monocenter retrospective study including all patients having undergone surgery from 2007 to 2015 with suspected or proven PJI. During surgery, both histopathological and microbiological samples were taken. Patients with a history of antimicrobial treatment 2 weeks prior to surgery were excluded. We considered as major criteria and gold standard for PJI diagnosis the presence of a sinus tract communication and/or the same microorganism in at least two cultures. RESULTS: Finally, 181 patients who underwent 309 surgeries were included. The median number of samples per surgery was 4 (interquartile range (IQR) = 3-5) for histopathology and 5 (IQR = 4-6) for microbiology. Major criteria were observed in 177 patients (57.3%), while positive histology in at least one intraoperative sample was present in 119 (38.5%). The concordance was 74%. The sensitivity and specificity of histopathology were 61% and 92% respectively. Available "histopathology-culture" sample pairs numbered 1247. Among them, positive histopathology was found in 292 samples (23%) and culture in 563 (45%). Concordance was 64%. The highest correlation was observed for very early infection (<1 month) (OR: 9.1, 95% CI: 3.6-23) and for virulent microorganisms, such as Staphylococcus aureus (OR: 7.8, 95% CI: 5.2-11.8), Streptococci (OR:7.8; 95% CI: 4-15.2) or Enterobacterales (OR: 7.4; 95% CI: 4.2-13.1). CONCLUSION: Histopathologic examination is a valuable criterion for PJI diagnosis, but it may lack sensitivity for chronic infections or due to low-virulence pathogens.

National trends in the initial diagnosis and management of carpal tunnel syndrome: results from the ELECTS (ELEctrophysiology in Carpal Tunnel Syndrome) study.

INTRODUCTION: The optimal role of nerve conduction studies (NCS) in management of carpal tunnel syndrome (CTS) is unclear, with no standardised guidance. This study aimed to identify variation in practice in the initial diagnosis of patients with suspected CTS, alongside evaluating how NCS findings influence clinical decision making. METHODS: A national multicentre collaborative survey was conducted in 2021. All centres providing surgery for CTS were invited to participate, primarily via social media. All middle-senior grade orthopaedic/plastic surgeons and advanced care practitioners that regularly manage new referrals for suspected CTS were eligible to respond. Local representatives at each participating site submitted their responses to a central team who collated and analysed the results. RESULTS: A total of 137 healthcare professionals responded from 18 UK NHS Trusts. Of these 137, 124 (91%) reported not employing any validated clinical questionnaires in their routine practice, preferring to rely on clinical diagnosis and/or NCS if available, whereas 84 (61%) utilised NCS to aid diagnosis, with significant differences among professionals with differing experience (p < 0.01). The most common methods for determining the severity of CTS were history, examination and NCS. In symptomatic CTS with confirmatory NCS, over 50% of clinicians would choose surgical decompression as their first-line intervention. In cases of either negative NCS or atypical presentation, 37% and 51%, respectively, would consider conservative management (eg, splintage) or steroid injection first line. CONCLUSIONS: With growing waiting lists for NCS and surgery, national consensus guidelines should be developed to support decision making, while maximising efficient utilisation of increasingly constrained resources.

Characteristics of Enterobacter cloacae prosthetic joint infections.

OBJECTIVES: Enterobacter cloacae prosthetic joint infections (PJI) are rare and poorly documented. PATIENTS AND METHODS: We conducted a retrospective and monocentric study in an orthopedic unit supporting complex bone and joint infections. Between 2012 and 2016 we collected background, clinical, biological, and microbiological data from 20 patients presenting with prosthetic joint infection and positive for E. cloacae, as well as data on their surgical and medical treatment and outcome. RESULTS: Infections were localized in the hip (n=14), knee (n=5), or ankle (n=1). The median time between arthroplasty and septic revision was three years. Fourteen patients (70%) had undergone at least two surgeries due to previous prosthetic joint infections. The median time between the last surgery and the revision for E. cloacae infection was 31 days. Eleven patients (55%) were infected with ESBL-producing strains. The most frequently used antibiotics were carbapenems (n=9), cefepime (n=7), quinolones (n=7), and fosfomycin (n=4). The infection was cured in 15 patients (78.9%) after a 24-month follow-up. Five patients had a recurrent infection with another microorganism and four patients had a relapse of E. cloacae infection. The global success rate was 52.7% (58.3% for DAIR and 75% for DAIR+ciprofloxacin). CONCLUSION: Prosthetic joint infections due to E. cloacae usually occur early after the last prosthetic surgery, typically in patients with complex surgical and medical histories. The success rate seems to be increased when DAIR is associated with ciprofloxacin.

Species and antimicrobial susceptibility testing of coagulase-negative staphylococci in periprosthetic joint infections.

The objective was to evaluate the distribution of coagulase-negative staphylococci (CNS) involved in periprosthetic-joint infections (PJIs) and to describe their susceptibility profile to antibiotics. We conducted a multicentre retrospective study in France, including 215 CNS PJIs between 2011 and 2015. CNS PJIs involved knees in 54% of the cases, hips in 39%, other sites in 7%. The distribution of the 215 strains was: Staphylococcus epidermidis 129 (60%), Staphylococcus capitis 24 (11%), Staphylococcus lugdunensis 21 (10%), Staphylococcus warneri 8 (4%), Staphylococcus hominis 7 (3%), Staphylococcus haemolyticus 7 (3%). More than half of the strains (52.1%) were resistant to methicillin, 40.9% to ofloxacin, 20% to rifampicin. The species most resistant to antibiotics were S. hominis, S. haemolyticus, S. epidermidis, with 69.7% of the strains resistant to methicillin and 30% simultaneously resistant to clindamycin, cotrimoxazole, ofloxacin and rifampicin. No strain was resistant to linezolid or daptomycin. In this study on CNS involved in PJIs, resistance to methicillin is greater than 50%. S. epidermidis is the most frequent and resistant species to antibiotics. Emerging species such S. lugdunensis, S. capitis and Staphylococcus caprae exhibit profiles more sensitive to antibiotics. The antibiotics most often active in vitro are linezolid and daptomycin.

Objective severity does not capture the impact of rosacea, acne scarring and photoaging in patients seeking laser therapy.

BACKGROUND: Measures of quality of life (QOL) and patient satisfaction are of great importance in dermatology, as both impact upon treatment adherence and health outcomes. Patients' assessment of QOL often differs from their doctors' predictions and their assessments of skin disease severity do not correlate with patients' own perceptions. The development of laser technology has facilitated successful treatment of many skin conditions, but studies on patient satisfaction are lacking. OBJECTIVES: Our aim was to determine the extent of discordance between patient and dermatologist-assessed disease severity and assess the impact of acne scarring, rosacea and photoaging on QOL. Our secondary aim was to assess patient satisfaction with laser therapy. METHODS: A prospective study of patients undergoing laser treatment for acne scarring, rosacea and photoaging was conducted over 1 year at the Skin & Cancer Foundation Australia. Subjective disease severity was determined using a visual analogue scale (VAS). Two dermatologists determined objective severity using validated grading scales to score photographs. QOL impact was measured by Skindex-16, satisfaction was measured using an amended Comprehensive Satisfaction Questionnaire (PSQ-18). RESULTS: A total of 147 individuals sought laser therapy for acne scarring, rosacea and photoaging. Dermatologists' subjective disease severity correlated weakly with patient-reported severity. All conditions negatively impacted upon QOL. Patients with rosacea had the most symptomatic impact; acne scarring was associated with the greatest self-esteem and social functioning issues; photoaging patients were the least affected. There were significant correlations between subjective severity assessment and Skindex-16 scores. There was notable discordance between dermatologist's skin severity assessment and patient's self-reported QOL impact. CONCLUSION: Skin conditions can have a profound impact on patient QOL, which is affected by patients' perception of disease severity and not fully appreciated by dermatologists' own severity assessments. Laser therapy is associated with high patient satisfaction.

Staphylococcus lugdunensis, a serious pathogen in periprosthetic joint infections: comparison to Staphylococcus aureus and Staphylococcus epidermidis.

OBJECTIVES: The aim of this study was to assess the characteristics of periprosthetic joint infection (PJI) due to Staphylococcus lugdunensis and to compare these to the characteristics of PJI due to Staphylococcus aureus and Staphylococcus epidermidis. METHODS: A retrospective multicentre study including all consecutive cases of S. lugdunensis PJI (2000-2014) was performed. Eighty-eight cases of staphylococcal PJI were recorded: 28 due to S. lugdunensis, 30 to S. aureus, and 30 to S. epidermidis, as identified by Vitek 2 or API Staph (bioMérieux). RESULTS: Clinical symptoms were more often reported in the S. lugdunensis group, and the median delay between surgery and infection was shorter for the S. lugdunensis group than for the S. aureus and S. epidermidis groups. Regarding antibiotic susceptibility, the S. lugdunensis strains were susceptible to antibiotics and 61% of the patients could be treated with levofloxacin + rifampicin. The outcome of the PJI was favourable for 89% of patients with S. lugdunensis, 83% with S. aureus, and 97% with S. epidermidis. CONCLUSION: S. lugdunensis is an emerging pathogen with a pathogenicity quite similar to that of S. aureus. This coagulase-negative Staphylococcus must be identified precisely in PJI, in order to select the appropriate surgical treatment and antibiotics .

Rapid Isolation of Staphylococcus aureus Pathogens from Infected Clinical Samples Using Magnetic Beads Coated with Fc-Mannose Binding Lectin.

Here we describe how Staphylococcus aureus bacteria can be rapidly isolated from clinical samples of articular fluid and synovial tissue using magnetic beads coated with the engineered chimeric human opsonin protein, Fc-mannose-binding lectin (FcMBL). The FcMBL-beads were used to capture and magnetically remove bacteria from purified cultures of 12 S. aureus strains, and from 8 articular fluid samples and 4 synovial tissue samples collected from patients with osteoarthritis or periprosthetic infections previously documented by positive S. aureus cultures. While the capture efficiency was high (85%) with purified S. aureus strains grown in vitro, direct FcMBL-bead capture from the clinical samples was initially disappointing (< 5% efficiency). Further analysis revealed that inhibition of FcMBL binding was due to coating of the bacteria by immunoglobulins and immune cells that masked FcMBL binding sites, and to the high viscosity of these complex biological samples. Importantly, capture of pathogens using the FcMBL-beads was increased to 76% efficiency by pretreating clinical specimens with hypotonic washes, hyaluronidase and a protease cocktail. Using this approach, S. aureus bacteria could be isolated from infected osteoarthritic tissues within 2 hours after sample collection. This FcMBL-enabled magnetic method for rapid capture and concentration of pathogens from clinical samples could be integrated upstream of current processes used in clinical microbiology laboratories to identify pathogens and perform antibiotic sensitivity testing when bacterial culture is not possible or before colonies can be detected.

[Pediatric brucellosis : A case report and literature review]. / Brucellose : revue de la littérature à propos d'un cas pédiatrique.

Brucellosis is an overlooked infection of widespread geographic distribution. This disease is rarely evoked when assessing unexplained pediatric fever, and only 20-30 cases (children and adults) are confirmed per year. Risk factors for contracting brucellosis are exposure to bodily fluids and consumption of unpasteurized dairy products from infected animals. Most cases of brucellosis are associated with traveling to or importing contaminated goods from endemic areas. Here, we report a case of brucellosis in a 16-month-old patient hospitalized for an acute febrile illness in a French general pediatric ward. An antibiotic regimen of rifampicin and co-trimoxazole given over 6 weeks led to successful cure without relapse. The child had eaten a cake made from unpasteurized goat's milk and imported from Oran, a region in Algeria. His mother had consumed the same cake and was hospitalized for brucellosis 15 days later. Clinicians should suspect brucellosis when encountering febrile patients who have traveled to endemic areas, been exposed to body fluids or products of abortion of farm animals, or consumed unpasteurized products.

Is Xpert MRSA/SA SSTI real-time PCR a reliable tool for fast detection of methicillin-resistant coagulase-negative staphylococci in periprosthetic joint infections?

Periprosthetic joint infections (PJIs) are frequently caused by methicillin-resistant coagulase-negative staphylococci (CoNS). Cultures remain the gold standard but often require a few days. Thus, a rapid test could be interesting to guide antibiotic strategy earlier. The purpose of this study was to evaluate the performances of RT-PCR Xpert® MRSA/SA technique for the detection of methicillin-resistant CoNS (MRCoNS) from deep samples in patients with PJIs. RT-PCR was tested on 72 samples. Sensitivity, specificity, positive predictive value, and negative predictive value of RT-PCR method were 0.36, 0.98, 0.90, and 0.74, respectively. Although RT-PCR may allow early microbial diagnosis of PJI due to Staphylococcus aureus (MSSA and MRSA), the low sensitivity and the high cost of this method to detect MRCoNS could limit its use in this field.

A study of transport suppression in an undoped AlGaAs/GaAs quantum dot single-electron transistor.

We report a study of transport blockade features in a quantum dot single-electron transistor, based on an undoped AlGaAs/GaAs heterostructure. We observe suppression of transport through the ground state of the dot, as well as negative differential conductance at finite source-drain bias. The temperature and magnetic field dependences of these features indicate the couplings between the leads and the quantum dot states are suppressed. We attribute this to two possible mechanisms: spin effects which determine whether a particular charge transition is allowed based on the change in total spin, and the interference effects which arise from coherent tunnelling of electrons in the quantum dot.

Impact of small-angle scattering on ballistic transport in quantum dots.

Disorder increasingly affects performance as electronic devices are reduced in size. The ionized dopants used to populate a device with electrons are particularly problematic, leading to unpredictable changes in the behavior of devices such as quantum dots each time they are cooled for use. We show that a quantum dot can be used as a highly sensitive probe of changes in disorder potential and that, by removing the ionized dopants and populating the dot electrostatically, its electronic properties become reproducible with high fidelity after thermal cycling to room temperature. Our work demonstrates that the disorder potential has a significant, perhaps even dominant, influence on the electron dynamics, with important implications for "ballistic" transport in quantum dots.

Obstructive sleep apnoea in a case of thyroglossal duct cyst carcinoma.

OBJECTIVES: To report a rare case of thyroglossal duct cyst carcinoma which presented with obstructive sleep apnoea, and to highlight the difficulties in making this clinical diagnosis. METHOD: Case report and review of the English language literature concerning thyroglossal duct cyst carcinoma. RESULTS: Thyroglossal duct cyst carcinoma is a rare clinical entity found in only approximately 1 per cent of all patients operated upon for thyroglossal duct cyst. This condition usually presents in an identical manner to its benign counterpart; atypical presentations have not previously been reported. Our patient is the first reported case of a thyroglossal duct cyst carcinoma first presenting with symptoms of obstructive sleep apnoea, without a neck mass. Complete surgical excision with total thyroidectomy and lymph node clearance was performed, in view of the positive lymph node metastases (seen on imaging) and the need for post-operative radioiodine therapy. CONCLUSION: Thyroglossal duct cyst carcinomas may present atypically, posing a diagnostic dilemma for the clinician. For patients diagnosed with obstructive sleep apnoea, it is imperative that a thorough otolaryngological examination be performed to exclude any underlying pathology.

Toxicity in three dogs from accidental oral administration of a topical endectocide containing moxidectin and imidacloprid.

Three dogs were presented with a history of oral administration of a topical endectocide containing imidacloprid and moxidectin. They were diagnosed with imidacloprid and moxidectin intoxication, having ingested doses ranging from 7.5 to 1.4 mg/kg of imidacloprid and 1.9 to 2.8 mg/kg of moxidectin. The three dogs were affected to different degrees of severity, but all displayed signs of ataxia, generalised muscle tremors, paresis, hypersalivation and disorientation. Temporary blindness occurred in two cases. The three dogs were tested for the presence of the multi-drug resistance 1 gene deletion, which can cause an increased sensitivity to the toxic effects of moxidectin, and were found to be negative. Treatment included gastrointestinal decontamination, intravenous fluid therapy and benzodiazepines to control muscle tremors. All three dogs made a complete recovery within 48 h of ingestion.

Activated coagulation times in normal cats and dogs using MAX-ACT tubes.

OBJECTIVE: To establish reference values for activated coagulation time (ACT) in normal cats and dogs, by visual assessment of clot formation using the MAX-ACT(TM) tube. SUBJECTS: We recruited 43 cats and 50 dogs for the study; 11 cats and 4 dogs were excluded from the statistical analysis because of abnormalities on clinical examination or laboratory testing including anaemia, prolonged prothrombin time (PT) or activated partial thromboplastin time (APTT), or insufficient plasma volume for comprehensive laboratory coagulation testing. PROCEDURE: Blood samples were collected via direct venipuncture for MAX-ACT, packed cell volume/total solids, manual platelet estimation and PT/APTT measurement. Blood (0.5 mL) was mixed gently in the MAX-ACT tube at 37 degrees C for 30 s, then assessed for clot formation every 5 to 10 s by tipping the tube gently on its side and monitoring for magnet movement. The endpoint was defined as the magnet lodging in the clot. The technique was tested with 10 dogs by collecting two blood samples from the same needle insertion and running a MAX-ACT on each simultaneously. RESULTS: In normal cats the mean MAX-ACT was 66 s (range 55-85 s). In normal dogs the mean was 71 s (range 55-80 s). There was no statistical difference between the first and second samples collected from the same needle insertion. CONCLUSIONS: and Clinical Relevance In both cats and dogs, a MAX-ACT result >85 s should be considered abnormal and further coagulation testing should be performed. Additionally, failure to discard the first few drops of the sample does not appear to significantly affect results.

Nonsurgical treatment of gastroesophageal intussusception in a puppy.

A 7-week-old, female Siberian husky was presented to Murdoch University Veterinary Hospital with an acute onset of respiratory distress and regurgitation. Thoracic imaging identified an intraluminal esophageal mass with concurrent aspiration pneumonia. Esophagoscopy identified the mass as stomach, and a diagnosis of gastroesophageal intussusception was made. The intussusception was reduced endoscopically, and fixation of the stomach to the abdominal wall was performed using a tube gastropexy. Gastroesophageal intussusception is an uncommon disease in small animals and traditionally has been managed surgically. This case report describes an alternative method of treatment associated with a good outcome in this puppy.

Persistently normal alanine aminotransferase levels in HIV/HCV-coinfected patients: the role of steatosis.

OBJECTIVE: The frequency and significance of, and liver biopsy findings associated with, a persistently normal alanine aminotransferase (ALT) level in HIV/hepatitis C virus (HCV)-coinfected patients are poorly characterized. We analysed factors associated with persistently normal ALT levels, defined as at least three consecutive normal ALT values over a 6-month period, in a group of 381 HIV/HCV-coinfected patients. METHODS: Patients were categorized into two groups according to ALT values: group 1, patients with persistently normal ALT levels; and group 2, patients with elevated ALT values. Possible interactions with host factors, HIV and HCV viral factors, antiretroviral treatment and histological features were examined. RESULTS: Thirty-six patients (9.4%) had persistently normal ALT levels. None of the 36 patients had cirrhosis. Seven patients (19.4%) had a METAVIR fibrosis score of F3. In multivariate analysis, a lower mean METAVIR inflammation score [odds ratio (OR) 0.50, 95% confidence interval (CI) 0.28-0.89; P=0.017], the absence of steatosis (OR 0.43, 95% CI 0.20-0.90; P=0.026) and HCV genotype 4 infection (OR 2.81, 95% CI 1.15-6.68; P=0.023) were associated with persistently normal ALT levels. CONCLUSION: The slower progression of chronic hepatitis in patients with persistently normal ALT levels could be related, in part, to a lower frequency of steatosis.