Performance of polymyxin B agar-based tests among carbapenem-resistant Enterobacterales.

Therapeutic options for infections caused by Carbapenem-resistant Enterobacterales (CRE) are restricted and include polymyxins-centred schemes. Evaluation of in vitro susceptibility is difficult and time consuming. Agar-based methodologies are an alternative to broth microdilution (BMD) and we aimed to evaluate the accuracy of those methods among Enterobacterales. A total of 137 non-duplicated CRE were subjected to polymyxin B BMD, agar screening test (Mueller Hinton plates containing 3 µg ml-1 of polymyxin B) and agar dilution (antibiotic serially diluted 0·25-64 µg ml-1 ). CRE of 42·3% were resistant to polymyxin B (MICs range: 0·25->64 µg ml-1 ) and 16·8% presented borderline MICs. Sensitivity, specificity, PPV and NPV were 86·2, 98·7, 98 and 90·7% for screening test and 86·2, 97·5, 96·1 and 90·6% for agar dilution. ME was 0·73 and 1·5% for screening and agar dilution respectively; VME was 5·8% for both techniques. In general, agar-based methods had a good performance. As far as we know, this is the first study to propose an agar screening test using polymyxin B instead of colistin.

Emergence of serotype 19A Streptococcus pneumoniae after PCV10 associated with a ST320 in adult population, in Porto Alegre, Brazil.

Use of pneumococcal conjugate vaccines has caused emergence of non-vaccine serotypes. No Brazilian data specifically about serotype 19A are available. We aimed to evaluate the frequency of occurrence, susceptibility profile and molecular epidemiology of serotype 19A before and after vaccine introduction in Brazil. Pneumococcal identification was performed by the conventional method. Strain serotype was determined by multiplex polymerase chain reaction (PCR) and/or Quellung reaction. Resistance was determined by Etest® and PCR was performed to determine the presence of macrolide resistance genes, ermB and/or mefA. Pneumococci were typed by Multilocus Sequence Typing. Thirty-eight serotype 19A Streptococcus pneumoniae were recovered, mostly from invasive diseases. Prevalence of serotype 19A increased following vaccination (from 3.5% before vaccination to 8.1% after, p = 0.04196). Non-susceptibility increased to most antimicrobials after vaccine introduction and was associated with clonal complex (CC)320. MLST showed nine different STs, which were grouped in one main CC: CC320 (63.9%). During the post-vaccination era, the frequency of this serotype increased significantly from 1.2% in 2011 to 18.5% in 2014 (p = 0.00001), with a concomitant decrease in the genetic variability: ST320 consistently predominated after vaccine-introduction (61.1%). Overall, our results showed a post-PCV10 increase in the frequency of serotype 19A. This was accompanied by a selection of CC320 and antimicrobial resistance.

Ilioinguinal approach to manage benign pelvic and acetabular tumors.

Benign osteoblastic and cystic lesions involving the anterior column and wall of the pelvis and acetabulum are technically difficult areas to approach and achieve successful surgical outcomes. Tumors in this area are rare, leaving little information in the literature regarding how best to surgically approach them. Previous authors have reported small series of patients treated using anteromedial, iliofemoral, and intracapsular dissections. The ilioinguinal approach has been extensively described and used in the modern-day treatment of pelvic and acetabular fractures involving the anterior column and wall. Despite its use for acetabular trauma, application of the ilioinguinal approach in the treatment of benign pelvic and acetabular lesions has not been described. We reviewed the management of 5 patients with benign pelvic or acetabular tumors treated using the ilioinguinal approach. Diagnoses included aneurysmal bone cysts in 3 patients and osteoid osteomas in 2 patients, involving the pelvic anterior column and wall. The approach has permitted satisfactory exposure of the lesions for operative treatment. At an average follow-up of 3 years (range, 2-4 years), excellent functional outcome and no recurrences were noted. There were 2 patients with lateral femoral cutaneous nerve palsies, both of which resolved completely by 8 weeks. Encouraging results from our study demonstrate a new application for the ilioinguinal approach in the treatment of benign anterior column and wall lesions of the pelvis and acetabulum.

Ewing sarcoma vs lymphoblastic lymphoma. A comparative immunohistochemical study.

To develop a practical immunohistochemistry panel for distinguishing lymphoblastic lymphoma from Ewing sarcoma (ES), we evaluated 17 ES and 27 lymphoblastic lymphoma and leukemia cases with antibodies to CD99, terminal deoxynucleotidyl transferase (TdT), leukocyte common antigen (LCA), CD43, CD79a, CD20, CD3, vimentin, and neuron-specific enolase (NSE). Three cases were bone lymphomas, 2 initially misdiagnosed as ES. All cases were CD99+. All lymphomas and leukemias were TdT+ compared to none of the ESs. None of the ESs expressed other lymphocytic markers, which were inconsistently expressed in the lymphomas and leukemias: CD43, 33%; LCA, 30%; CD79a, 19%; CD3, 19%; and CD20, 7%. Of the ESs, 88% were vimentin positive compared with 23% of lymphomas and leukemias. Vimentin was stronger and more diffuse in ES. NSE did not reliably stain any cases. When faced with the differential diagnosis of ES vs lymphoblastic lymphoma, an immunohistochemical panel that includes antibodies to CD99 and TdT is useful. Both epitopes are well preserved in fixed and decalcified tissue. A panel composed of antibodies to CD99 and TdT, in conjunction with other lymphocytic markers and vimentin, is highly sensitive and specific.

Arthroplasty-associated malignant fibrous histiocytoma: two case reports.

AIMS: Sarcoma localized to the site of an arthroplasty procedure is a rare occurrence, and detailed histological depictions and descriptions are limited. We report the clinicopathological findings in two cases of arthroplasty-associated malignant fibrous histiocytoma (MFH) and review the literature. METHODS AND RESULTS: The patients were an elderly man and woman. Medical histories, radiographs and slides were reviewed. Immunohistochemistry, electron microscopy, cytogenetics, and electron dispersion spectroscopy were performed in one case. Both were destructive femoral bone tumours that appeared 2 and 8 years post-total hip arthroplasty, and pursued aggressive clinical courses. The histology was similar in both tumours, consisting of high-grade, pleomorphic sarcoma with numerous osteoclastic giant cells, prominent phagocytic activity, and entrapped particles of bone cement. Literature review disclosed 14 previous reports of arthroplasty-associated MFH, representing the most common phenotype. A number of materials and factors related to arthroplasty procedure, such as metal corrosion, wear debris, osteonecrosis, and chronic inflammation, have been implicated as causative agents. CONCLUSIONS: Arthroplasty-associated MFH is a rare and aggressive tumour. Although the aetiology remains unclear, the small number of arthroplasty-associated sarcomas compared with the large number of joint replacement operations performed over the past four decades suggests a coincidental as opposed to a causal relation.

Photopenic bone scan osteomyelitis: a clinical perspective.

Eighty-one pediatric patients had nuclear bone-imaging studies confirmatory of osteomyelitis during the past 10 years. Seven (8.6%) of 81 had "cold" osteomyelitis. These seven patients were all toxic [mean temperature (T), 39.9 degrees C; heart rate (HR), 145 beats/min], all had markedly elevated erythrocyte sedimentation rates (mean ESR, 76 mm/h), and six of seven had both confirmatory bone and blood cultures. All patients required surgical intervention. The average length of hospital stay for these seven patients was 32 days (range, 8-65 days). A control group of matched patients with "hot" osteomyelitis was constructed for statistical evaluation. This analysis confirmed significantly increased temperature, resting pulse rate, ESR, length of hospital stay, and rate of surgical intervention in patients with cold versus hot osteomyelitis. Patients with osteomyelitis presenting as a cold defect on bone imaging appeared to have a more aggressive type of bone infection, often requiring aggressive medical and surgical intervention adequately to control this infectious process.

Pediatric bone tumors.

A variety of benign and malignant bone tumors can affect the metabolically active pediatric skeleton. A thorough investigation with pertinent imaging studies can establish an appropriate differential diagnosis and frequently allows distinction between benign and malignant tumors. By using a multidisciplinary approach to the treatment of malignant tumors, a number of advances have been made. Further research is needed to gain more understanding and improve on the remarkable advances of the past 20 years.