Andy O. Miller

Detection of malaria in Malaysia by nested polymerase chain reaction amplification of dried blood spots on filter papers

A modified nested polymerase chain reaction (PCR) method for detection of Plasmodium falciparum, P. vivax and P. malariae was combined with a simple blood collection and deoxyribonucleic acid (DNA) extraction method and evaluated in Malaysia. Finger-prick blood samples from 46 hospital patients and 120 individuals living in malaria endemic areas were spotted on filter papers and dried. The simple Chelex method was used to prepare DNA templates for the nested PCR assay. Higher malaria prevalence rates for both clinical (78.2%) and field samples (30.8%) were obtained with the nested PCR method than by microscopy (76.1% and 27.5%, respectively). Nested PCR was more sensitive than microscopy in detecting mixed P. falciparum and P. vivax infections, detected 5 more malaria samples than microscopy on the first round of microscopical examination, and detected malaria in 3 microscopically negative samples. Nested PCR failed to detect parasite DNA in 2 microscopically positive samples, an overall sensitivity of 97.4% compared to microscopy. The nested PCR method, when coupled with simple dried blood spot sampling, is a useful tool for collecting accurate malaria epidemiological data, particularly in remote regions of the world.

Comparison of mucosal and systemic humoral immune responses after transcutaneous and oral immunization strategies

In order to compare the ability of transcutaneous and oral immunization strategies to induce mucosal and systemic immune responses, we inoculated mice transcutaneously with cholera toxin (CT) or the non-toxic B subunit of cholera toxin (CtxB), or orally with Peru2(pETR1), an attenuated vaccine strain of Vibrio cholerae expressing CtxB. In addition, we also evaluated dual immunization regimens (oral inoculation with transcutaneous boosting, and transcutaneous immunization with oral boosting) in an attempt to optimize induction of both mucosal and systemic immune responses. We found that transcutaneous immunization with purified CtxB or CT induces much more prominent systemic IgG anti-CtxB responses than does oral inoculation with a vaccine vector strain of V. cholerae expressing CtxB. In comparison, anti-CtxB IgA in serum, stool and bile were comparable in mice either transcutaneously or orally immunized. Overall, the most prominent systemic and mucosal anti-CtxB responses occurred in mice that were orally primed with Peru2(pETR1) and transcutaneously boosted with CT. Our results suggest that combination oral and transcutaneous immunization strategies may most prominently induce both mucosal and systemic humoral responses.

Travel-associated disease among US residents visiting US GeoSentinel clinics after return from international travel

BACKGROUND US residents make 60 million international trips annually. Family practice providers need to be aware of travel-associated diseases affecting this growing mobile population. OBJECTIVE To describe demographics, travel characteristics and clinical diagnoses of US residents who present ill after international travel. METHODS Descriptive analysis of travel-associated morbidity and mortality among US travellers seeking care at 1 of the 22 US practices and clinics participating in the GeoSentinel Global Surveillance Network from January 2000 to December 2012. RESULTS Of the 9624 ill US travellers included in the analysis, 3656 (38%) were tourist travellers, 2379 (25%) missionary/volunteer/research/aid workers (MVRA), 1580 (16%) travellers visiting friends and relatives (VFRs), 1394 (15%) business travellers and 593 (6%) student travellers. Median (interquartile range) travel duration was 20 days (10-60 days). Pre-travel advice was sought by 45%. Hospitalization was required by 7%. Compared with other groups of travellers, ill MVRA travellers returned from longer trips (median duration 61 days), while VFR travellers disproportionately required higher rates of inpatient care (24%) and less frequently had received pre-travel medical advice (20%). Illnesses of the gastrointestinal tract were the most common (58%), followed by systemic febrile illnesses (18%) and dermatologic disorders (17%). Three deaths were reported. Diagnoses varied according to the purpose of travel and region of exposure. CONCLUSIONS Returning ill US international travellers present with a broad spectrum of travel-associated diseases. Destination and reason for travel may help primary health care providers to generate an accurate differential diagnosis for the most common disorders and for those that may be life-threatening.

ERK signaling, but not c-Raf, is required for gonadotropin-releasing hormone (GnRH)-induced regulation of Nur77 in pituitary gonadotropes.

Stimulation of pituitary gonadotropes by hypothalamic GnRH leads to the rapid expression of several immediate early genes that play key roles in orchestrating the response of the gonadotrope to hypothalamic stimuli. Elucidation of the signaling mechanisms that couple the GnRH receptor to this immediate early gene repertoire is critical for understanding the molecular basis of GnRH action. Here we identify signaling mechanisms that underlie regulation of the orphan nuclear receptor Nur77 as a GnRH-responsive immediate early gene in αT3-1 cells and mouse gonadotropes in culture. Using a variety of approaches, we show that GnRH-induced transcriptional upregulation of Nur77 in αT3-1 cells is dependent on calcium, protein kinase C (PKC), and ERK signaling. Transcriptional activity of Nur77 within the gonadotrope is regulated posttranslationally by GnRH signaling via PKC but not ERK activity. Surprisingly, neither activation of the ERK pathway nor the transcriptional response of Nur77 to GnRH requires the activity of c-Raf kinase. In corroboration of these results, Nur77 responsiveness to GnRH was maintained in gonadotropes from mice with pituitary-targeted ablation of c-Raf kinase. In contrast, gonadotropes from mice with pituitary deficiency of ERK signaling failed to up-regulate Nur77 after GnRH stimulation. These results further clarify the role of ERK and PKC signaling in regulation of the GnRH-induced immediate early gene program as well as GnRH-induced transcription-stimulating activity of Nur77 in the gonadotrope and shed new light on the complex functional organization of this signaling pathway in the pituitary gonadotrope.

Periprosthetic joint infection in patients with inflammatory joint disease: a review of risk factors and current approaches to diagnosis and management.

BackgroundPrevention, early identification, and effective management of periprosthetic joint infection (PJI) in patients with inflammatory joint disease (IJD) present unique challenges for physicians. Discontinuing disease-modifying anti-rheumatoid drugs (DMARDs) perioperatively may reduce immunosuppression and infection risk at the expense of increasing disease flares. Interpreting traditional diagnostic markers of PJI can be difficult due to disease-related inflammation.PurposesThis review is designed to answer how to (1) manage immunosuppressive/DMARD therapy perioperatively, (2) diagnose PJI in patients with IJD, and (3) treat PJI in this population.MethodsThe PubMed database was searched for relevant articles with subsequent review by independent authors.ResultsWhile there is evidence to support the use of methotrexate perioperatively in RA patients, it remains unclear whether using anti-tumor necrosis factor medications perioperatively increases the risk of surgical site infections. Serum erythrocyte sedimentation rate and C-reactive protein can be useful for diagnosis of PJI in this population, but only as part of comprehensive workup that ultimately relies upon sampling of joint fluid. Management of PJI depends on several clinical factors including duration of infection and the likelihood of biofilm presence, the infecting organism, sensitivity to antibiotic therapy, and host immune status. The evidence suggests that two-stage revision or resection arthroplasty is more likely to eradicate infection, particularly when MRSA is the pathogen.ConclusionImmunosuppression and baseline inflammatory changes in the IJD population can complicate the prevention, diagnosis, and treatment of PJI. Understanding the increase in risk associated with IJD and its treatment is essential for proper management when patients undergo lower extremity arthroplasty.

Simple blood-spot sampling with nested polymerase chain reaction detection for epidemiology studies on Brugia malayi.

In the absence of a suitable Brugia malayi antigen detection assay, PCR remains one of the more sensitive alternatives to Giemsa-stained thick blood films for B. malayi detection. The need for refrigerated storage and transportation of blood has limited the use of PCR for large-scale epidemiology studies in remote endemic areas. Here we report simple finger-prick blood-spot collection, a one-tube DNA template extraction method and the development of a B. malayi-specific nested PCR assay. The assay was tested on 145 field samples and was positive for all 30 microscopy-positive samples and for an additional 13 samples which were microscopy-negative.

Update in Diagnosis and Treatment of Diabetic Foot Infections

Foot infections are a major cause of morbidity and mortality in diabetics. Evaluation of diabetic foot infections often requires clinical, radiologic, laboratory, and microbiologic assessment. Osteomyelitis has a profound impact on the prognosis and management of these infections, and diagnosis can be difficult; the gold standard remains bone biopsy. Despite a panoply of studies, the optimal management of diabetic foot infections remains poorly understood. Antibiotics, surgery, rehabilitation and/or off-loading, and glycemic control remain the cornerstones of treatment; alternative therapies remain largely unproven.

Epidemiology of Deep Surgical Site Infections After Pediatric Spinal Fusion Surgery

Study Design. Single-institution, retrospective case series. Objective. To determine whether the microbiology of deep surgical site infections (SSIs) after spinal fusion surgery for deformity has changed over the last decade at our institution. Summary of Background Data. SSI after pediatric spinal deformity surgery results in significantly increased patient morbidity and health care costs. Although risk factors are multifactorial, prophylactic and treatment antibiotic coverage is based in part on historical epidemiologic data, which may evolve over time. Methods. This study represents a retrospective review of clinical and microbiology records of patients less than 21 years old who underwent spinal deformity surgery at a single institution between 2000 and 2012. Patients were included who underwent index surgery at our institution and developed a deep SSI. Patients with growth-preserving spine constructs were excluded. Results. The overall incidence of deep SSI was 3.6% (39/1094). The incidence of deep SSI following primary surgery was 3.3% (34/1034) and 8.3% (5/60) following revision surgery. The incidence of deep SSI varied by primary diagnosis: idiopathic (1.0%), neuromuscular (14.3%), syndromic (5.3%), congenital (5.7%), and kyphosis (0.0%). The most common inciting pathogens were Staphylococcus epidermidis (26%), methicillin-sensitive Staphylococcus aureus (MSSA, 18%), Propionibacterium acnes (P. acnes; 18%), and Escherichia coli (18%). Sixteen of the 18 (89%) gram-negative infections occurred in neuromuscular patients (P = 0.006). Between 2000 and 2006 and between 2007 and 2012, MSSA occurred in 2/18 (11%) and 5/21 (24%) of cases (P = 0.41), methicillin-resistant S. aureus occurred in 1/18 (6%) and 3/21 (14%) (P = 0.61), and P. acnes occurred in 3/18 (17%) and 4/21 (19%) (P = 1.0). Conclusion. The epidemiology of deep SSI following spinal fusion for deformity in pediatric patients at our institution has not changed significantly during 13 years. Prophylactic antibiotic coverage for both gram-positive and gram-negative organisms may be indicated for patients with primary neuromuscular diagnoses. Level of Evidence: 4

Cost-Effectiveness of Staphylococcus aureus Decolonization Strategies in High-Risk Total Joint Arthroplasty Patients

BACKGROUND The risk of prosthetic joint infection increases with Staphylococcus aureus colonization. The cost-effectiveness of decolonization is controversial. We evaluated cost-effectiveness decolonization protocols in high-risk arthroplasty patients. METHODS An analytical model evaluated risk under 3 protocols: 4 swabs, 2 swabs, and nasal swab alone. These were compared to no-screening and universal decolonization strategies. Cost-effectiveness was evaluated from the hospital, patient, and societal perspective. RESULTS Under base case conditions, universal decolonization and 4-swab strategies were most effective. The 2-swab and universal decolonization strategy were most cost-effective from patient and societal perspectives. From the hospital perspective, universal decolonization was the dominant strategy (much less costly and more effective). CONCLUSION S aureus decolonization may be cost-effective for reducing prosthetic joint infections in high-risk patients. These results may have important implications for treatment of patients and for cost containment in a bundled payment system.

L5-S1 Achromobacter xylosoxidans infection secondary to oxygen-ozone therapy for the treatment of lumbosacral disc herniation: a case report and review of the literature.

Study Design. Case report and literature review. Objective. To present a unique case of Achromobacter xylosoxidans infection secondary to oxygen-ozone therapy for the treatment of L5–S1 disc herniation. Summary of Background Data. Oxygen-ozone therapy is a minimally invasive technique for the treatment of lumbar disc herniations, with unproven efficacy and few reported complications. Achromobacter xylosoxidans is an opportunistic pathogen that inhabits aquatic environments and is a rare cause of osteomyelitis. To the best of our knowledge, this is the first report of A. xylosoxidans spondylodiscitis in the lumbar spine and the third report of spinal infection after intradiscal oxygen-ozone chemonucleolysis in the English literature. Methods. The medical records, operative reports, and radiographical imaging studies of a single patient were retrospectively reviewed. Results. A 29-year-old female patient who previously underwent oxygen-ozone therapy for L5–S1 disc herniation presented to our institution with a 5-month history of intractable back and leg pain. The patients laboratory studies were within normal limits and did not indicate signs of an active infection. Her physical examination revealed globally decreased muscle strength (4/5) and hyperesthesia in the lower extremities. Magnetic resonance imaging and computed tomography revealed severe disc degeneration and vertebral body endplate changes at L5–S1, in addition to paravertebral soft tissue swelling consistent with a previous infection. Given the severity of symptoms, the patient underwent anterior lumbar interbody fusion and posterior segmental instrumentation at L5–S1. Histopathological evaluation of the disc material confirmed the diagnosis of chronic osteomyelitis and septic discitis at L5–S1. Intraoperative cultures grew A. xylosoxidans and Propionibacterium acnes. The patient had prompt improvement in her level of pain and was discharged on a 6-week course of piperacillin-tazobactam without complication. Conclusion. This first report of A. xylosoxidans vertebral infection secondary to oxygen-ozone therapy illustrates the wide variety of environmental pathogens that can complicate the percutaneous treatment of degenerative vertebral disease. Level of Evidence: N/A