Validation of Thermal Imaging and the ALT-70 Prediction Model to Differentiate Cellulitis From Pseudocellulitis.

Importance: Cellulitis is misdiagnosed in up to 30% of cases due to mimic conditions termed pseudocellulitis. The resulting overuse of antibiotics is a threat to patient safety and public health. Surface thermal imaging and the ALT-70 (asymmetry, leukocytosis, tachycardia, and age ≥70 years) prediction model have been proposed as tools to help differentiate cellulitis from pseudocellulitis. Objectives: To validate differences in skin surface temperatures between patients with cellulitis and patients with pseudocellulitis, assess the optimal temperature measure and cut point for differentiating cellulitis from pseudocellulitis, and compare the performance of skin surface temperature and the ALT-70 prediction model in differentiating cellulitis from pseudocellulitis. Design, Setting, and Participants: This prospective diagnostic validation study was conducted among patients who presented to the emergency department with acute dermatologic lower extremity symptoms from October 11, 2018, through March 11, 2020. Statistical analysis was performed from July 2020 to March 2021 with additional work conducted in September 2023. Main Outcomes and Measures: Temperature measures for affected and unaffected skin were obtained. Cellulitis vs pseudocellulitis was assessed by a 6-physician, independent consensus review. Differences in temperature measures were compared using the t test. Logistic regression was used to identify the temperature measure and associated cut point with the optimal performance for discriminating between cellulitis and pseudocellulitis. Diagnostic performance characteristics for the ALT-70 prediction model, surface skin temperature, and both combined were also assessed. Results: The final sample included 204 participants (mean [SD] age, 56.6 [16.5] years; 121 men [59.3%]), 92 (45.1%) of whom had a consensus diagnosis of cellulitis. There were statistically significant differences in all skin surface temperature measures (mean temperature, maximum temperature, and gradients) between cellulitis and pseudocellulitis. The maximum temperature of the affected limb for patients with cellulitis was 33.2 °C compared with 31.2 °C for those with pseudocellulitis (difference, 2.0 °C [95% CI, 1.3-2.7 °C]; P < .001). The maximum temperature was the optimal temperature measure with a cut point of 31.2 °C in the affected skin, yielding a mean (SD) negative predictive value of 93.5% (4.7%) and a sensitivity of 96.8% (2.3%). The sensitivity of all 3 measures remained above 90%, while specificity varied considerably (ALT-70, 22.0% [95% CI, 15.8%-28.1%]; maximum temperature of the affected limb, 38.4% [95% CI, 31.7%-45.1%]; combination measure, 53.9% [95% CI, 46.5%-61.2%]). Conclusions and Relevance: In this large diagnostic validation study, significant differences in skin surface temperature measures were observed between cases of cellulitis and cases of pseudocellulitis. Thermal imaging and the ALT-70 both demonstrated high sensitivity, but specificity was improved by combining the 2 measures. These findings support the potential of thermal imaging, alone or in combination with the ALT-70 prediction model, as a diagnostic adjunct that may reduce overdiagnosis of cellulitis.

Quality improvement study on the effectiveness of intranasal povidone-iodine decolonization on surgery patients.

Background: Surgical site infection prevention and treatment remains a challenge in healthcare settings globally. The routine use of intranasal mupirocin for decolonization has challenges and preoperative intranasal povidone-iodine decolonization is another option. The purpose of this quality improvement study was to assess if a one-time preoperative intranasal povidone-iodine application could reduce the risk of the likelihood of nasal carriage of Staphylococcus aureus after surgery. Methods: Ambulatory Surgery Center patients were enrolled in an intranasal povidone-iodine decolonization quality improvement study as they reported at the pre-operative holding area. Pre-decolonization intranasal samples were collected, followed by intranasal application of povidone-iodine. Patients waited for a minimum of 20 minutes after application before proceeding with surgery. Nasal samples were again collected after surgery. Each sample was tested for S. aureus colonization using the 16S rRNA-mecA-nuc triplex polymerase chain reaction, standard biochemical tests, and qualitative culturing. Findings: In the 98 patients enrolled, 36% of these patients had intranasal colonization with S. aureus by 16S rRNA-mecA-nuc triplex polymerase chain reaction before surgery. Using a qualitative culture technique, 28% of patients tested positive for S. aureus before surgery and 20% of patients tested positive for S. aureus after surgery (P = 0.039). Conclusion: Intranasal preoperative povidone-iodine is an effective strategy in the decolonization of S. aureus from the nares if properly implemented.

A quality improvement study on the relationship between intranasal povidone-iodine and anesthesia and the nasal microbiota of surgery patients.

INTRODUCTION: The composition of the nasal microbiota in surgical patients in the context of general anesthesia and nasal povidone-iodine decolonization is unknown. The purpose of this quality improvement study was to determine: (i) if general anesthesia is associated with changes in the nasal microbiota of surgery patients and (ii) if preoperative intranasal povidone-iodine decolonization is associated with changes in the nasal microbiota of surgery patients. MATERIALS AND METHODS: One hundred and fifty-one ambulatory patients presenting for surgery were enrolled in a quality improvement study by convenience sampling. Pre- and post-surgery nasal samples were collected from patients in the no intranasal decolonization group (control group, n = 54). Pre-decolonization nasal samples were collected from the preoperative intranasal povidone-iodine decolonization group (povidone-iodine group, n = 97). Intranasal povidone-iodine was administered immediately prior to surgery and continued for 20 minutes before patients proceeded for surgery. Post-nasal samples were then collected. General anesthesia was administered to both groups. DNA from the samples was extracted for 16S rRNA sequencing on an Illumina MiSeq. RESULTS: In the control group, there was no evidence of change in bacterial diversity between pre- and post-surgery samples. In the povidone-iodine group, nasal bacterial diversity was greater in post-surgery, relative to pre-surgery (Shannon's Diversity Index (P = 0.038), Chao's richness estimate (P = 0.02) and Inverse Simpson index (P = 0.027). Among all the genera, only the relative abundance of the genus Staphylococcus trended towards a decrease in patients after application (FDR adjusted P = 0.06). Abundant genera common to both povidone-iodine and control groups included Staphylococcus, Bradyrhizobium, Corynebacterium, Dolosigranulum, Lactobacillus, and Moraxella. CONCLUSIONS: We found general anesthesia was not associated with changes in the nasal microbiota. Povidone-iodine treatment was associated with nasal microbial diversity and decreased abundance of Staphylococcus. Future studies should examine the nasal microbiota structure and function longitudinally in surgical patients receiving intranasal povidone-iodine.

Comparing skin surface temperature to clinical documentation of skin warmth in emergency department patients diagnosed with cellulitis.

Objective: To compare clinical documentation of skin warmth to patient report and quantitative skin surface temperatures of patients diagnosed with cellulitis in the emergency department (ED). Methods: Adult patients (≥18 years) presenting to the ED with an acute complaint involving visible erythema of the lower extremity were prospectively enrolled. Those diagnosed with cellulitis were included in this analysis. Participant report of skin warmth was recorded and skin surface temperature values were obtained from the affected and corresponding unaffected area of skin using thermal cameras. Average temperature (Tavg) was extracted from each image and the difference in Tavg between the affected and unaffected limb was calculated (Tgradient). Clinical documentation of skin warmth was compared to patient report and measured skin warmth (Tgradient >0°C). Results: Among 126 participants diagnosed with cellulitis, 110 (87%) exhibited objective warmth (Tgradient >0°C) and 58 (53%) of these cases had warmth documented in the physical examination. Of those with objective warmth, 86 (78%) self-reported warmth and 7 (6%) had warmth documented in their history of present illness (HPI) (difference = 72%, 95% confidence interval [CI]: 62%-82%; P < 0.001). A significant difference was observed for Tavg affected when warmth was documented (32.1°C) versus not documented (31.0°C) in the physical examination (difference = 1.1°C, 95% CI: 0.29-1.94; P = 0.0083). No association was found between Tgradient and patient-reported or HPI-documented warmth. Conclusions: The majority of ED-diagnosed cellulitis exhibited objective warmth, yet significant discordance was observed between patient-reported, clinician-documented, and measured warmth. This raises concerns over inadequate documentation practices and/or the poor sensitivity of touch as a reliable means to assess skin surface temperature. Introduction of objective temperature measurement tools could reduce subjectivity in the assessment of warmth in patients with suspected cellulitis.

Risk Factors and Mortality for Atypical Presentation of COVID-19 Infection in Hospitalized Patients - Lessons From the Early Pandemic.

OBJECTIVE: To assess the clinical epidemiology and outcomes of patients hospitalized with COVID-19 who did not experience fever and cough during the early pandemic. METHODS: Retrospective cohort of all patients admitted during March 13, 2020 through May 13, 2020 with laboratory-confirmed COVID-19 to 3 tertiary-care hospitals. Patient-level data (demographic, clinical manifestations, comorbid illnesses, inpatient treatment) were analyzed. The main outcome variable was atypical presentation, defined as any hospitalized patient with COVID-19 infection who did not experience both fever and cough. We identified risk factors for atypical presentation on univariate and multivariate analyses and assessed 30-day mortality differences via survival analysis. RESULTS: Of 163 patients in the study, 39 (24%) were atypical. On univariate analysis, atypical cases were significantly more likely to be older, reside in a long-term-care facility (LTCF), and have underlying diabetes mellitus, stroke, or cardiac disease; present without dyspnea or myalgia, have lower C-reactive proteins (CRP) and higher beta-natriuretic peptides. They were less likely to receive intensive care unit care or specific COVID-19 treatments (P < .05). The incidence of acute respiratory failure was not significantly different between the groups. On logistic regression, atypical cases were significantly more likely to be LTCF residents (P = 0.003) and have a lower average CRP (P = 0.01). Atypical cases had significantly higher 30-day mortality (hazard ratio 3.4 [95% CI, 1.6 - 7.2], P = 0.002). CONCLUSION: During the first pandemic surge, COVID-19 patients without inflammatory signs and symptoms were more likely to be LTCF residents and had higher mortality. Timely recognition of these atypical presentations may have prevented spread and improved clinical outcomes.

Nasal povidone-iodine implementation for preventing surgical site infections: Perspectives of surgical nurses.

INTRODUCTION: Preoperative nasal decolonization of surgical patients with nasal povidone-iodine (PI) has potential to eliminate pathogenic organisms responsible for surgical site infections. However, data on implementation of PI for quality improvement in clinical practice is limited. The purpose of this study was to evaluate the implementation feasibility, fidelity and acceptability of intranasal PI solution application by surgical nurses using the Integrated Promoting Action on Research Implementation in Health Services (i-PARIHS) conceptual framework. MATERIALS AND METHODS: Using the i-PARIHS framework to frame questions and guide interview content areas, we conducted 15 semi-structured interviews of pre- and post-operative care nurses in two facilities. We analyzed the data using deductive content analysis to evaluate nurses' experience and perceptions on preoperative intranasal PI solution decolonization implementation. Open coding was used to analyze the data to ensure all relevant information was captured. RESULTS: Each facility adopted a different quality improvement implementation strategy. The mode of facilitation, training, and educational materials provided to the nurses varied by facility. Barriers identified included lack of effective communication, insufficient information and lack of systematic implementation protocol. Action taken to mitigate some of the barriers included a collaboration between the study team and nurses to develop a systematic written protocol. The training assisted nurses to systematically follow the implementation protocol smoothly to ensure PI administration compliance, and to meet the goal of the facilities. Nurses' observations and feedback showed that PI did not cause any adverse effects on patients. CONCLUSIONS: We found that PI implementation was feasible and acceptable by nurses and could be extended to other facilities. However further studies are required to ensure standardization of PI application.

Screening for Beta-Lactam Allergy in Joint Arthroplasty Patients to Improve Surgical Prophylaxis Practice.

BACKGROUND: The reliability of patient-reported penicillin allergies has been disputed. A Drug Allergy Clinic (DAC) was established at our institution in combination with an electronic best practice alert (BPA) in the Orthopedic Clinic. Joint arthroplasty patients with a reported history of beta-lactam allergy (HOBA) were preoperatively referred via the BPA to the DAC. The purpose of this study was to determine the effectiveness of beta-lactam allergy screening in enabling the surgical team to optimize antimicrobial prophylaxis. METHODS: Between February 2013 and May 2015, 161 patients with a HOBA were referred to the DAC where they underwent penicillin skin testing (PST), a drug challenge to a beta-lactam antibiotic, and/or had no intervention depending on the history obtained. RESULTS: PST was performed on 140 of 161 (87%) patients. A negative PST was noted in 139 (99%) patients, indicating no penicillin allergy. Cefazolin was safe to use in 145 (90%) patients evaluated. Significantly more patients evaluated in the DAC vs those not seen got cefazolin in any surgical prophylaxis regimen (90% vs 77%) without any adverse perioperative reactions. Concurrently, the use of non-beta-lactam antibiotics was significantly less in the patients evaluated vs not evaluated (16% vs 27%). The overall use of cefazolin in orthopedic surgeries in patients with HOBA was >84% over the course of the study period. CONCLUSION: Beta-lactam allergy screening using a BPA and a DAC promotes the use of standard surgical prophylaxis with cefazolin. Joint arthroplasty surgeons should consider implementing allergy screening programs to promote antimicrobial stewardship.

Screening Patients Undergoing Total Hip or Knee Arthroplasty with Perioperative Urinalysis and the Effect of a Practice Change on Antimicrobial Use.

OBJECTIVE To identify predictors of treatment for urinary tract infections (UTI) among patients undergoing total hip (THA) or knee (TKA) arthroplasties and to assess an intervention based on these predictors. DESIGN We conducted a retrospective cohort study of 200 consecutive patients undergoing THA/TKA between February 21, 2011, and June 30, 2011, to identify predictors of treatment for UTI and a prospective cohort study of 50 patients undergoing these procedures between May 21, 2012, and July 17, 2012, to assess the association of signs or symptoms and UTI treatment. We then conducted a before-and-after study to assess whether implementing an intervention affected the frequency of treatment for UTI before or after THA/TKA. SETTING The orthopedics department of a university health center. PATIENTS Patients undergoing THA or TKA. INTERVENTION Surgeons revised their UTI screening and treatment practices. RESULTS Positive leukocyte esterase (P5 (P=.01; P=.01) were associated with preoperative or postoperative UTI treatment. In the prospective study, 12 patients (24%) had signs and symptoms consistent with UTI. The number of patients treated for presumed UTI decreased 80.2% after the surgeons changed their practices, and surgical site infection (SSI) rates, including prosthetic joint infections (PJIs), did not increase. CONCLUSIONS Urine leukocyte esterase and white blood cell count were the strongest predictors of treatment for UTI before or after THA/TKA. The intervention was associated with a significant decrease in treatment for UTI, and SSI/PJI rates did not increase. Infect Control Hosp Epidemiol 2017;38:281-286.

Risk Factors for Surgical Site Infections Following Adult Spine Operations.

OBJECTIVE To identify risk factors for surgical site infections (SSIs) after spine operations. DESIGN Case-control study of SSIs among patients undergoing spine operations. SETTING An academic health center. PATIENTS We studied patients undergoing spinal fusions or laminectomies at the University of Iowa Hospitals and Clinics from January 1, 2007, through June 30, 2009. We included patients who acquired SSIs meeting the National Healthcare Safety Network definition. We randomly selected controls among patients who had spine operations during the study period and did not meet the SSI definition. RESULTS In total, 54 patients acquired SSIs after 2,309 spine operations (2.3 per 100 procedures). SSIs were identified a median of 20 days after spinal fusions and 17 days after laminectomies; 90.7% were identified after discharge and 72.2% were deep incisional or organ-space infections. Staphylococcus aureus caused 53.7% of SSIs. Of patients with SSIs, 64.9% (fusion) and 70.6% (laminectomy) were readmitted and 59.5% (fusion) and 64.7% (laminectomy) underwent reoperation. By multivariable analysis, increased body mass index, Surgical Department A, fusion of 4-8 vertebrae, and operation at a thoracic or lumbar/sacral level were significant risk factors for SSIs after spinal fusions. Lack of private insurance and hypertension were significant risk factors for SSIs after laminectomies. Surgeons from Department A were more likely to use nafcillin or vancomycin for perioperative prophylaxis and to do more multilevel fusions than surgeons from Department B. CONCLUSIONS SSIs after spine operations significantly increase utilization of healthcare resources. Possible remediable risk factors include obesity, hypertension, and perioperative antimicrobial prophylaxis. Infect Control Hosp Epidemiol 2016;1458-1467.

Cultures of diabetic foot ulcers without clinical signs of infection do not predict outcomes.

OBJECTIVE: We examined associations between ulcer bioburden and ulcer outcomes in neuropathic diabetic foot ulcers (DFUs) that lacked clinical signs of infection. RESEARCH DESIGN AND METHODS: Three dimensions of bioburden (i.e., microbial load, microbial diversity, and the presence of likely pathogens) were measured at baseline using swab cultures obtained by Levine's technique. Subjects were assessed every 2 weeks for 26 weeks to determine the rate of healing and development of infection-related complications. Foot ulcers were off-loaded using total-contact casts and routinely debrided. To establish associations between bioburden and rate of healing, Cox proportional hazards and least squares regression were used after adjusting for ulcer depth, surface area, and duration. RESULTS: A total of 77 subjects completed the study. Sixty-five (84.4%) had ulcers that healed during follow-up; weeks-to-closure ranged from 2 to 26 (median 4.0). Mean (± SD) percent reduction in surface area/week was 25.0% (± 23.33). Five (6.5%) of the DFUs developed an infection-related complication. None of the bioburden dimensions (i.e., microbial load, microbial diversity, or presence of likely pathogens) was significantly associated with weeks-to-closure or percent reduction in surface area per week. Weeks-to-closure was best predicted by ulcer duration, depth, and surface area (c-statistic = 0.75). CONCLUSIONS: Culturing DFUs that showed no clinical signs of infection had no predictive value for outcomes of DFUs managed with total-contact casts and routine debridement. These findings support recommendations of the Infectious Disease Society of America that culturing and antibiotics should be avoided in treating DFUs that show no clinical signs of infection.

Concordance of nasal and diabetic foot ulcer staphylococcal colonization.

Nasal carriage of Staphylococcus aureus (SA) is an important risk factor for surgical site infections. The goal of this study was to investigate the concordance between nasal and diabetic foot ulcer (DFU) SA carriage. Seventy-nine subjects with DFUs were assessed for nasal and DFU colonization with SA, including methicillin-resistant SA (MRSA). Twenty-five (31.6%) subjects had nares colonization with SA; 29 (36.7%) had DFU colonization with SA. Seven (8.8%) subjects had nares colonization with MRSA, and 7 (8.8%) had DFU colonization with MRSA. Ulcer duration was associated with MRSA presence (P = 0.01). Sensitivity and specificity of positive nasal SA colonization with positive DFU colonization were 41% and 74%. We found substantial discordance between SA strains colonizing DFU and the nasal cavity. The poor positive predictive values for SA isolation in a DFU based on nasal carriage suggests that SA colonization of a DFU by endogenous SA strains cannot be assumed.