Interventions in the management of diabetes-related foot infections: A systematic review.

The optimal approaches to managing diabetic foot infections remain a challenge for clinicians. Despite an exponential rise in publications investigating different treatment strategies, the various agents studied generally produce comparable results, and high-quality data are scarce. In this systematic review, we searched the medical literature using the PubMed and Embase databases for published studies on the treatment of diabetic foot infections from 30 June 2018 to 30 June 2022. We combined this search with our previous literature search of a systematic review performed in 2020, in which the infection committee of the International Working Group on the Diabetic Foot searched the literature until June 2018. We defined the context of the literature by formulating clinical questions of interest, then developing structured clinical questions (Patients-Intervention-Control-Outcomes) to address these. We only included data from controlled studies of an intervention to prevent or cure a diabetic foot infection. Two independent reviewers selected articles for inclusion and then assessed their relevant outcomes and methodological quality. Our literature search identified a total of 5,418 articles, of which we selected 32 for full-text review. Overall, the newly available studies we identified since 2018 do not significantly modify the body of the 2020 statements for the interventions in the management of diabetes-related foot infections. The recent data confirm that outcomes in patients treated with the different antibiotic regimens for both skin and soft tissue infection and osteomyelitis of the diabetes-related foot are broadly equivalent across studies, with a few exceptions (tigecycline not non-inferior to ertapenem [±vancomycin]). The newly available data suggest that antibiotic therapy following surgical debridement for moderate or severe infections could be reduced to 10 days and to 3 weeks for osteomyelitis following surgical debridement of bone. Similar outcomes were reported in studies comparing primarily surgical and predominantly antibiotic treatment strategies in selected patients with diabetic foot osteomyelitis. There is insufficient high-quality evidence to assess the effect of various recent adjunctive therapies, such as cold plasma for infected foot ulcers and bioactive glass for osteomyelitis. Our updated systematic review confirms a trend to a better quality of the most recent trials and the need for further well-designed trials to produce higher quality evidence to underpin our recommendations.

IWGDF/IDSA guidelines on the diagnosis and treatment of diabetes-related foot infections (IWGDF/IDSA 2023).

The International Working Group on the Diabetic Foot (IWGDF) has published evidence-based guidelines on the management and prevention of diabetes-related foot diseases since 1999. The present guideline is an update of the 2019 IWGDF guideline on the diagnosis and management of foot infections in persons with diabetes mellitus. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework was used for the development of this guideline. This was structured around identifying clinically relevant questions in the P(A)ICO format, determining patient-important outcomes, systematically reviewing the evidence, assessing the certainty of the evidence, and finally moving from evidence to the recommendation. This guideline was developed for healthcare professionals involved in diabetes-related foot care to inform clinical care around patient-important outcomes. Two systematic reviews from 2019 were updated to inform this guideline, and a total of 149 studies (62 new) meeting inclusion criteria were identified from the updated search and incorporated in this guideline. Updated recommendations are derived from these systematic reviews, and best practice statements made where evidence was not available. Evidence was weighed in light of benefits and harms to arrive at a recommendation. The certainty of the evidence for some recommendations was modified in this update with a more refined application of the GRADE framework centred around patient important outcomes. This is highlighted in the rationale section of this update. A note is also made where the newly identified evidence did not alter the strength or certainty of evidence for previous recommendations. The recommendations presented here continue to cover various aspects of diagnosing soft tissue and bone infections, including the classification scheme for diagnosing infection and its severity. Guidance on how to collect microbiological samples, and how to process them to identify causative pathogens, is also outlined. Finally, we present the approach to treating foot infections in persons with diabetes, including selecting appropriate empiric and definitive antimicrobial therapy for soft tissue and bone infections; when and how to approach surgical treatment; and which adjunctive treatments may or may not affect the infectious outcomes of diabetes-related foot problems. We believe that following these recommendations will help healthcare professionals provide better care for persons with diabetes and foot infections, prevent the number of foot and limb amputations, and reduce the patient and healthcare burden of diabetes-related foot disease.

Diagnosis of infection in the foot of patients with diabetes: A systematic review.

BACKGROUND: Securing an early accurate diagnosis of diabetic foot infections and assessment of their severity are of paramount importance since these infections can cause great morbidity and potential mortality and present formidable challenges in surgical and antimicrobial treatment. METHODS: In June 2022, we searched the literature using PubMed and EMBASE for published studies on the diagnosis of diabetic foot infection (DFI). On the basis of pre-determined criteria, we reviewed prospective controlled, as well as non-controlled, studies in English. We then developed evidence statements based on the included papers. RESULTS: We selected a total of 64 papers that met our inclusion criteria. The certainty of the majority of the evidence statements was low because of the weak methodology of nearly all of the studies. The available data suggest that diagnosing diabetic foot infections on the basis of clinical signs and symptoms and classified according to the International Working Group of the Diabetic Foot/Infectious Diseases Society of America scheme correlates with the patient's likelihood of the need for hospitalisation, lower extremity amputation, and risk of death. Elevated levels of selected serum inflammatory markers such as erythrocyte sedimentation rate (ESR), C-reactive protein and procalcitonin are supportive, but not diagnostic, of soft tissue infection. Culturing tissue samples of soft tissues or bone, when care is taken to avoid contamination, provides more accurate microbiological information than culturing superficial (swab) samples. Although non-culture techniques, especially next-generation sequencing, are likely to identify more bacteria from tissue samples including bone than standard cultures, no studies have established a significant impact on the management of patients with DFIs. In patients with suspected diabetic foot osteomyelitis, the combination of a positive probe-to-bone test and elevated ESR supports this diagnosis. Plain X-ray remains the first-line imaging examination when there is suspicion of diabetic foot osteomyelitis (DFO), but advanced imaging methods including magnetic resonance imaging (MRI) and nuclear imaging when MRI is not feasible help in cases when either the diagnosis or the localisation of infection is uncertain. Intra-operative or non-per-wound percutaneous biopsy is the best method to accurately identify bone pathogens in case of a suspicion of a DFO. Bedside percutaneous biopsies are effective and safe and are an option to obtain bone culture data when conventional (i.e. surgical or radiological) procedures are not feasible. CONCLUSIONS: The results of this systematic review of the diagnosis of diabetic foot infections provide some guidance for clinicians, but there is still a need for more prospective controlled studies of high quality.

Exome Sequencing of a Blastomycosis Case-Control Cohort From Manitoba and Northwestern Ontario, Canada.

BACKGROUND: Blastomycosis is a pulmonary disease caused by Blastomyces spp., a group of pathogenic dimorphic fungi endemic to a number of geographic regions, specifically Manitoba and northwestern Ontario, Canada. Immunosuppression is a major risk factor affecting disease susceptibility, yet host immunity is not well understood. Genetic immunodeficiencies can also influence disease, with variants in IL6, GATA2 and VDBP shown to influence susceptibility. Additional genetic factors in disease susceptibility and severity remain undetected. Our study seeks to identify potential genetic risk factors in a blastomycosis case-control cohort from Manitoba and northwestern Ontario, Canada. METHODS: Exomes from 18 blastomycosis cases and 9 controls were sequenced, variants were identified and filtered for accuracy and quality. We performed candidate gene prioritisation and variant aggregation to identify genetic associations and explored the full exome dataset. RESULTS: Ninety-nine genetic variants in 42 candidate genes were identified in the exome dataset. No variants associated with susceptibility were identified in a single-variant analysis although two non-synonymous variants in TYK2 were enriched among cases suggesting a possible role in susceptibility. Gene-based association analysis found variants in TLR1 enriched in controls (p = 0.024) suggesting a possible protective effect. Gene cluster analysis identified genetic variants in genes of chromatin remodelling, proteasome and intraflagellar transport significantly enriched in cases (false discovery rates < 14%). CONCLUSIONS: The findings in this study show novel associations with blastomycosis susceptibility. A better understanding of host immunity and genetic predisposition to Blastomyces infection can help to inform clinical practice for improved outcomes.

IWGDF/IDSA Guidelines on the Diagnosis and Treatment of Diabetes-related Foot Infections (IWGDF/IDSA 2023).

The International Working Group on the Diabetic Foot (IWGDF) has published evidence-based guidelines on the management and prevention of diabetes-related foot diseases since 1999. The present guideline is an update of the 2019 IWGDF guideline on the diagnosis and management of foot infections in persons with diabetes mellitus. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework was used for the development of this guideline. This was structured around identifying clinically relevant questions in the P(A)ICO format, determining patient-important outcomes, systematically reviewing the evidence, assessing the certainty of the evidence, and finally moving from evidence to the recommendation. This guideline was developed for healthcare professionals involved in diabetes-related foot care to inform clinical care around patient-important outcomes. Two systematic reviews from 2019 were updated to inform this guideline, and a total of 149 studies (62 new) meeting inclusion criteria were identified from the updated search and incorporated in this guideline. Updated recommendations are derived from these systematic reviews, and best practice statements made where evidence was not available. Evidence was weighed in light of benefits and harms to arrive at a recommendation. The certainty of the evidence for some recommendations was modified in this update with a more refined application of the GRADE framework centred around patient important outcomes. This is highlighted in the rationale section of this update. A note is also made where the newly identified evidence did not alter the strength or certainty of evidence for previous recommendations. The recommendations presented here continue to cover various aspects of diagnosing soft tissue and bone infections, including the classification scheme for diagnosing infection and its severity. Guidance on how to collect microbiological samples, and how to process them to identify causative pathogens, is also outlined. Finally, we present the approach to treating foot infections in persons with diabetes, including selecting appropriate empiric and definitive antimicrobial therapy for soft tissue and bone infections; when and how to approach surgical treatment; and which adjunctive treatments may or may not affect the infectious outcomes of diabetes-related foot problems. We believe that following these recommendations will help healthcare professionals provide better care for persons with diabetes and foot infections, prevent the number of foot and limb amputations, and reduce the patient and healthcare burden of diabetes-related foot disease.

Charcot arthropathy outcomes after early referral to a regional tertiary care foot clinic.

BACKGROUND: Community physicians may not encounter Charcot arthropathy frequently, and its symptoms and signs may be nonspecific. Patients often have a delay of several months before receiving a formal diagnosis and referral for specialty care. However, limited Canadian data are available. We evaluated the clinical history, treatment and outcomes of patients treated for Charcot arthropathy after prompt referral and diagnosis. METHODS: We performed a retrospective chart review of 76 patients with diabetes (78 feet) who received nonoperative treatment for Charcot arthropathy in a specialty foot clinic between Jan. 20, 2009, and Mar. 26, 2018. Patients were referred to the foot clinic by community physicians for evaluation or were pre-existing patients at the foot clinic with new-onset Charcot arthropathy. RESULTS: Of the 78 feet included in our analyses, 52 feet (67%) were evaluated initially by a community physician and referred to the foot clinic, where they were seen within 3 ± 5 weeks. The remaining 26 feet (33%) were already being treated at the foot clinic. Most feet had swelling, erythema, warmth, a palpable pulse and loss of protective sensation. Ulcers were present initially in 23 feet (29%). Sixty-four feet (82%) with Charcot arthropathy were in Eichenholtz classification stage 1 and most had midfoot involvement. Nonoperative treatment included total contact casting (60 feet, 77%). Mean duration of nonoperative treatment until resolution for 55 feet (71%) was 6 ± 5 months. Surgery was performed on 20 feet (26%) for the treatment of infection and recurrent ulcer associated with deformity, including 6 (8%) lower limb amputations. CONCLUSION: Charcot arthropathy may resolve in most feet with early referral and nonoperative treatment, but remains a limb-threatening condition.

Intravenous immune globulin in septic shock: a Canadian national survey of critical care medicine and infectious disease specialist physicians.

PURPOSE: This national survey evaluated the perceived efficacy and safety of intravenous immune globulin (IVIG) in septic shock, self-reported utilization patterns, barriers to use, the population of interest for further trials and willingness to participate in future research of IVIG in septic shock. METHODS: We conducted a cross-sectional survey of critical care and infectious diseases physicians across Canada. We summarized categorical item responses as counts and proportions. We developed a multivariable logistic regression model to identify physician-level predictors of IVIG use in septic shock. RESULTS: Our survey was disseminated to 674 eligible respondents with a final response rate of 60%. Most (91%) respondents reported having prescribed IVIG to patients with septic shock at least once, 86% for septic shock due to necrotizing fasciitis, 52% for other bacterial toxin-mediated causes of septic shock, and 5% for undifferentiated septic shock. The majority of respondents expressed uncertainty regarding the impact of IVIG on mortality (97%) and safety (95%) in septic shock. Respondents were willing to participate in further IVIG research with 98% stating they would consider enrolling their patients into a trial of IVIG in septic shock. Familiarity with published evidence was the single greatest predictor of IVIG use in septic shock (odds ratio, 10.2; 95% confidence interval, 3.4 to 30.5; P < 0.001). CONCLUSIONS: Most Canadian critical care and infectious diseases specialist physicians reported previous experience using IVIG in septic shock. Respondents identified inadequacy of existing research as the greatest barrier to routine use of IVIG in septic shock. Most respondents support the need for further studies on IVIG in septic shock, and would consider enrolling their own patients into a trial of IVIG in septic shock.

RéSUMé: OBJECTIF : Cette enquête nationale a évalué l'efficacité et l'innocuité perçues des immunoglobulines intraveineuses (IgIV) dans le contexte du choc septique, les habitudes d'utilisation autodéclarées, les obstacles à l'utilisation de cette modalité, les populations à explorer pour des études futures et la volonté de participer aux recherches futures sur les IgIV et le choc septique. MéTHODE : Nous avons mené une enquête transversale auprès de médecins intensivistes et spécialistes des maladies infectieuses au Canada. Nous avons résumé les réponses de chaque point catégorique en tant que dénombrement et proportions. Nous avons mis au point un modèle de régression logistique multivariée afin d'identifier les prédicteurs, au niveau des médecins, d'une utilisation des IgIV en cas de choc septique. RéSULTATS : Notre sondage a été acheminé à 674 médecins admissibles et nous avons obtenu un taux de réponse final de 60 %. La plupart (91%) des répondants ont indiqué avoir prescrit des IgIV aux patients en choc septique au moins une fois, 86 % pour un choc septique dû à une fasciite nécrosante, 52 % pour des chocs septiques d'autres étiologies médiées par des toxines bactériennes, et 5 % dans des cas de choc septique non différencié. La majorité des répondants ont exprimé de l'incertitude quant à l'incidence des IgIV sur la mortalité (97 %) et l'innocuité (95 %) lors de choc septique. Les répondants étaient disposés à participer à d'autres recherches sur les IgIV, 98 % déclarant qu'ils envisageraient d'inscrire leurs patients à une étude sur les IgIV et le choc septique. La familiarité avec les données probantes publiées était le plus grand prédicteur d'utilisation d'IgIV dans un contexte de choc septique (rapport de cotes, 10,2; intervalle de confiance à 95 %, 3,4 à 30,5; P < 0,001). CONCLUSION : La plupart des médecins intensivistes et spécialistes des maladies infectieuses canadiens ont rapporté avoir une expérience antérieure d'utilisation d'IgIV en cas de choc septique. Les répondants ont identifié l'insuffisance de la recherche existante comme le plus grand obstacle à l'utilisation systématique d'IgIV dans les cas de choc septique. La plupart des répondants appuient la nécessité d'études plus approfondies sur les IgIV et le choc septique et envisageraient d'inscrire leurs propres patients à une étude sur les IgIV dans un contexte de choc septique.

Rectal Perforation by an Intrauterine Device Leading to Fatal Intra-Abdominal Sepsis and Necrotizing Fasciitis.

BACKGROUND: Colorectal injury from an intrauterine device (IUD) is rare but may lead to major complications. CASE: A 55-year-old woman presented to a tertiary care hospital with 4 days of generalized weakness, confusion, dysuria, and lower back pain. She provided a vague history of an unsuccessful attempt to remove an IUD 30 years prior. A computed tomography scan demonstrated an IUD in the rectal lumen, with gluteal and pelvic gas and fluid collections. Emergency surgery found necrotizing fasciitis. Despite multiple debridements, sigmoidoscopic IUD removal, and long-term intravenous antibiotics, the patient died from sepsis and multiorgan failure. CONCLUSION: IUDs require proper monitoring and timely removal to prevent potential complications associated with organ perforation.

Emergence of pstS-Null Vancomycin-Resistant Enterococcus faecium Clone ST1478, Canada, 2013-2018.

Rates of vancomycin-resistant enterococci bloodstream infections have remained relatively low in Canada. We recently observed an increase of 113% in these infections rates, which coincided with emergence of Enterococcus faecium pstS-null sequence type 1478. The proportion of this sequence type increased from 2.7% to 38.7% for all tested isolates from 2013-2018.

Peripheral Artery Disease: Its Adverse Consequences With and Without CKD.

RATIONALE & OBJECTIVES: Chronic kidney disease (CKD) is a potent risk factor for macrovascular disease and death. Peripheral artery disease (PAD) is more common in patients with CKD and is associated with lower-limb complications and mortality. We sought to compare the prevalence of PAD in and outside the setting of kidney disease and examine how PAD affects the risk for adverse health outcomes, specifically lower-limb complications, cardiovascular events, and survival. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: 453,573 adult residents of Manitoba with at least 1 serum creatinine measurement between 2007 and 2014. EXPOSURE: PAD defined by hospital discharge diagnosis codes and medical claims. OUTCOMES: All-cause mortality, cardiovascular events, and lower-limb complications, including foot ulcers and nontraumatic amputations. ANALYTICAL APPROACH: Survival analysis using Cox proportional hazards models. RESULTS: The prevalence of PAD in our study population was 4.5%, and patients with PAD were older, were more likely to be male, and had a higher burden of comorbid conditions, including diabetes and CKD. PAD was associated with higher risks for all-cause mortality, cardiovascular events, and lower-limb complications in patients with estimated glomerular filtration rate (eGFR) ≥ 60mL/min/1.73m2, those with CKD GFR categories 3 to 5 (G3-G5), and those treated by dialysis (CKD G5D). Although HRs for PAD were lower in the CKD population, event rates were higher as compared with those with eGFR≥60mL/min/1.73m2. In particular, compared with patients with eGFR≥60mL/min/1.73m2 and without PAD, patients with CKD G5D had 10- and 12-fold higher risks for lower-limb complications, respectively (adjusted HRs of 10.36 [95% CI, 8.83-12.16] and 12.02 [95% CI, 9.58-15.08] for those without and with PAD, respectively), and an event rate of 75/1,000 patient-years. LIMITATIONS: Potential undercounting of PAD and complications using administrative codes and the limited ability to examine quality-of-care indicators for PAD. CONCLUSIONS: PAD is more common in patients with CKD G3-G5 and G5D compared with those with eGFR≥60mL/min/1.73m2 and frequently leads to lower-limb complications. Medical interventions and care pathways specifically designed to slow or prevent the development of lower-limb complications in this population are urgently needed.

Interventions in the management of infection in the foot in diabetes: a systematic review.

The optimal approaches to managing diabetic foot infections remain a challenge for clinicians. Despite an exponential rise in publications investigating different treatment strategies, the various agents studied generally produce comparable results, and high-quality data are scarce. In this systematic review, we searched the medical literature using the PubMed and Embase databases for published studies on the treatment of diabetic foot infections as of June 2018. This systematic review is an update of previous reviews, the first of which was undertaken in 2010 and the most recent in 2014, by the infection committee of the International Working Group of the Diabetic Foot. We defined the context of literature by formulating clinical questions of interest, then developing structured clinical questions (PICOs) to address these. We only included data from controlled studies of an intervention to prevent or cure a diabetic foot infection. Two independent reviewers selected articles for inclusion and then assessed their relevant outcomes and the methodological quality. Our literature search identified a total of 15 327 articles, of which we selected 48 for full-text review; we added five more studies discovered by means other than the systematic literature search. Among these selected articles were 11 high-quality studies published in the last 4 years and two Cochrane systematic reviews. Overall, the outcomes in patients treated with the different antibiotic regimens for both skin and soft tissue infection and osteomyelitis of the diabetic foot were broadly equivalent across studies, except that treatment with tigecycline was inferior to ertapenem (±vancomycin). Similar outcomes were also reported in studies comparing primarily surgical and predominantly antibiotic treatment strategies in selected patients with diabetic foot osteomyelitis. There is insufficient high-quality evidence to assess the effect of various adjunctive therapies, such as negative pressure wound therapy, topical ointments or hyperbaric oxygen, on infection related outcomes of the diabetic foot. In general, the quality of more recent trial designs are better in past years, but there is still a great need for further well-designed trials to produce higher quality evidence to underpin our recommendations.

Diagnosis of infection in the foot in diabetes: a systematic review.

BACKGROUND: Securing an early accurate diagnosis of diabetic foot infections and assessment of their severity are of paramount importance since these infections can cause great morbidity and potentially mortality and present formidable challenges in surgical and antimicrobial treatment. METHODS: In June 2018, we searched the literature using PuEbMed and EMBASE for published studies on the diagnosis of diabetic foot infection. On the basis of predetermined criteria, we reviewed prospective controlled, as well as noncontrolled, studies in any language, seeking translations for those not in English. We then developed evidence statements on the basis of the included papers. RESULTS: From the 4242 records screened, we selected 35 papers that met our inclusion criteria. The quality of all but one of the evidence statements was low because of the weak methodology of nearly all of the studies. The available data suggest that diagnosing diabetic foot infections on the basis of clinical signs and symptoms and classified according to the International Working Group of the Diabetic Foot scheme correlates with the patient's likelihood of ulcer healing, of lower extremity amputation, and risk of death. Elevated levels of selected serum inflammatory markers are supportive, but not diagnostic, of soft tissue or bone infection. In patients with suspected diabetic foot osteomyelitis, both a positive probe-to-bone test and an elevated erythrocyte sedimentation rate are strongly associated with its presence. Culturing tissue samples of soft tissues or bone, when care is taken to avoid contamination, provides more accurate microbiological information than culturing superficial (swab) samples. Plain X-ray remains the first-line imaging examination when there is suspicion of diabetic foot osteomyelitis, but advanced imaging methods help in cases when either the diagnosis or the localization of infection is uncertain. CONCLUSION: The results of this first reported systematic review on the diagnosis of diabetic foot infections provide some guidance for clinicians, but there is a need for more prospective controlled studies of high quality.

Guidelines on the diagnosis and treatment of foot infection in persons with diabetes (IWGDF 2019 update).

The International Working Group on the Diabetic Foot (IWGDF) has published evidence-based guidelines on the prevention and management of diabetic foot disease since 1999. This guideline is on the diagnosis and treatment of foot infection in persons with diabetes and updates the 2015 IWGDF infection guideline. On the basis of patient, intervention, comparison, outcomes (PICOs) developed by the infection committee, in conjunction with internal and external reviewers and consultants, and on systematic reviews the committee conducted on the diagnosis of infection (new) and treatment of infection (updated from 2015), we offer 27 recommendations. These cover various aspects of diagnosing soft tissue and bone infection, including the classification scheme for diagnosing infection and its severity. Of note, we have updated this scheme for the first time since we developed it 15 years ago. We also review the microbiology of diabetic foot infections, including how to collect samples and to process them to identify causative pathogens. Finally, we discuss the approach to treating diabetic foot infections, including selecting appropriate empiric and definitive antimicrobial therapy for soft tissue and for bone infections, when and how to approach surgical treatment, and which adjunctive treatments we think are or are not useful for the infectious aspects of diabetic foot problems. For this version of the guideline, we also updated four tables and one figure from the 2016 guideline. We think that following the principles of diagnosing and treating diabetic foot infections outlined in this guideline can help clinicians to provide better care for these patients.

Perioperative implications of thoracic decortications: a retrospective cohort study.

PURPOSE: An increasing number of thoracic decortications have been performed in Manitoba, from five in 2007 to 45 in 2014. The primary objective of this study was to define the epidemiology of decortications in Manitoba. The secondary objective was to compare patients who underwent decortication due to primary infectious vs non-infectious etiology with respect to their perioperative outcomes. METHODS: Data for this cohort study were extracted from consecutive charts of all adult patients who underwent a decortication in Manitoba from 2007-2014 inclusive. RESULTS: One hundred ninety-two patients underwent a decortication. The most frequent disease processes resulting in a decortication were pneumonia (60%), trauma (13%), malignancy (8%), and procedural complications (5%). The number of decortications due to complications of pneumonia rose at the greatest rate, from three cases in 2007 to 29 cases in 2014. Performing a decortication for an infectious vs a non-infectious etiology was associated with a higher rate of the composite postoperative outcome of myocardial infarction, acute kidney injury, need of vasopressors for > 12 hr, and mechanical ventilation for > 48 hr (44.4% vs 24.2%, respectively; relative risk, 1.83; 95% confidence interval, 1.1 to 2.9; P = 0.01). CONCLUSION: There has been a ninefold increase in decortications over an eight-year period. Potential causes include an increase in the incidence of pneumonia, increased organism virulence, host changes, and changes in practice patterns. Patients undergoing decortication for infectious causes had an increased risk for adverse perioperative outcomes. Anesthesiologists need to be aware of the high perioperative morbidity of these patients and the potential need for postoperative admission to an intensive care unit.

Development and validation of a novel single nucleotide polymorphism (SNP) panel for genetic analysis of Blastomyces spp. and association analysis.

BACKGROUND: Single nucleotide polymorphism (SNP) genotyping is increasingly being utilized for molecular typing of pathogens and is cost-effective, especially for large numbers of isolates. The goals of this study were 1) to develop and validate a SNP assay panel for genetic analysis of Blastomyces spp., 2) ascertain whether microsatellite genotyping and the SNP genotyping with the developed panel resolve identical genetic groups, and 3) explore the utility of SNPs for examining phylogenetic and virulence questions in humans. METHODS: Three hundred sixty unique Blastomyces spp. isolates previously genotyped with microsatellite markers were genotyped with the MassARRAY® SNP genotyping system (Agena Bioscience™, San Diego, CA), for a custom panel of 28 SNPs. Clinical presentation data was analyzed for association with SNP variants. RESULTS: Three hundred twenty-three Blastomyces spp. isolates (90 %) were successfully genotyped by SNP analysis, with results obtained for at least 27 of 28 assays. For 99.7 % of isolates tested by both genotyping methods, microsatellite genetic group assignment correlated with species assignment based on internal transcribed spacer 2 (ITS2) genotyping, with Group 1 (Gr 1) being equivalent to B. gilchristii and Group 2 (Gr 2) being equivalent to B. dermatitidis. Thirteen isolates were genetic hybrids by one or both methods of genotyping and were difficult to assign to a particular genetic group or species. Fifteen SNP loci showed significantly different alleles in cases of pulmonary vs disseminated disease, at a p-value of <0.01 or less. CONCLUSIONS: This study is the largest genotyping study of Blastomyces spp. isolates and presents a new method for genetic analysis with which to further explore the relationship between the genetic diversity in Blastomyces spp. and clinical disease presentation. We demonstrated that microsatellite Gr 1 is equivalent to B. gilchristii and Gr 2 is equivalent to B. dermatitidis. We also discovered potential evidence of infrequent recombination between the two Blastomyces spp. Several Blastomyces spp. SNPs were identified as associated with dissemination or pulmonary disease presentation, but additional work is needed to examine virulence SNPs separately within B. dermatitidis and B. gilchristii.