A New Surgical Site Infection Risk Score: Infection Risk Index in Cardiac Surgery

Risk factors for surgical site infection following cardiac surgery in a region endemic for multidrug resistant organisms

OBJECTIVES

To identify risk factors for surgical site infections following cardiosurgery in an area endemic for multidrug resistant organisms.

DESIGN

Single-center, historical cohort study including patients who underwent cardiosurgery during a 6-year period (2014-2020).

SETTING

Joint Commission International accredited, multiorgan transplant center in Palermo, Italy.

MAIN OUTCOME MEASURES

Surgical site infection was the main outcome.

RESULTS

On a total of 3609 cardiosurgery patients, 184 developed surgical site infection (5.1 %). Intestinal colonization with multidrug resistant organisms was more frequent in patients with surgical site infections (69.6 % vs. 33.3 %; p < 0.001). About half of surgical site infections were caused by Gram-negative bacteria (n = 97; 52.7 %). Fifty surgical site infections were caused by multidrug resistant organisms (27.1 %), with extended-spectrum Beta-lactamase-producing Enterobacterales (n = 16; 8.7 %) and carbapenem-resistant Enterobacterales (n = 26; 14.1 %) being the predominant resistance problem. However, in only 24 of surgical site infections caused by multidrug resistant organisms (48 %), mostly carbapenem-resistant Enterobacterales (n = 22), a pathogen match between the rectal surveillance culture and surgical site infections clinical culture was demonstrated. Nevertheless, multivariate logistic regression analysis identified a rectal swab culture positive for multidrug resistant organisms as an independent risk factor for SSI (odds ratio 3.95, 95 % confidence interval 2.79-5.60). Other independent risk factors were female sex, chronic dialysis, diabetes mellitus, previous cardiosurgery, previous myocardial infarction, being overweight/obese, and longer intubation time.

CONCLUSION

In an area endemic for carbapenem-resistant Enterobacterales, intestinal colonization with multidrug resistant organisms was recognized as independent risk factor for surgical site infections.

IMPLICATIONS FOR CLINICAL PRACTICE

No causal relationship between colonization with resistant pathogens and subsequent infection could be demonstrated. However, from a broader epidemiological perspective, having a positive multidrug resistant organisms colonization status appeared a risk factor for surgical site infections. Therefore, strict infection control measures to prevent cross-transmission remain pivotal (e.g., nasal decolonization, hand hygiene, and skin antisepsis).

Antibiotic prophylaxis in urologic interventions: Who, when, where?

BACKGROUND

Periprocedural prophylaxis in medicine encompasses the set of measures (physical, chemical, and pharmacological) used to reduce the risk of infection. Antibiotic prophylaxis (AP) refers to the administration of a short-term regimen of antibiotics shortly before a medical procedure to reduce the risk of infectious complications that can result from diagnostic and therapeutic interventions. The outspreading growth of multidrug-resistant bacterial species and changes in the bacterial local ecosystem have impeded the development of a unique scheme of AP in urology.

OBJECTIVES

To review the literature and current guidelines regarding AP for urological diagnostic and therapeutic procedures, and to define agents, timing, and occasions when administering pharmacological prophylaxis. Secondly, according to current literature, to open new scenarios where AP can be useful or useless.

RESULTS

Major gaps in evidence still exist in this field. AP appears useful in many invasive procedures and some sub-populations at risk of infectious complications. AP is not routinely recommended for urodynamic exams, diagnostic cystoscopy, and extracorporeal shock-wave lithotripsy. The available data regarding the use of AP during the transperineal prostate biopsy are still unclear; conversely, in the case of the transrectal approach AP is mandatory. AP is still considered the gold standard for the prevention of postoperative infective complications in the case of ureteroscopy, percutaneous nephrolithotomy, endoscopic resection of bladder tumor, endoscopic resection of the prostate, and prosthetic or major surgery.

CONCLUSION

The review highlights the complexity of determining the appropriate candidates for AP, emphasizing the importance of considering patient-specific factors such as comorbidities, immunocompetence, and the nature of the urologic intervention. The evidence suggests that a one-size-fits-all approach may not be suitable, and a tailored strategy based on the specific procedure and patient characteristics is essential.

Overview of Antibiotic Prophylaxis in Orthopaedic and Cardiac Procedures

Antibiotic prophylaxis (AP) in surgical procedures is commonly used to prevent infections that may occur after operations. There are multiple factors that can contribute to increased risk of postsurgical complications that include prolonged hospitalization, reoperation, and readmissions. One of the strategies of decreasing the risk of bacterial contamination and developing infections is preprocedural antibiotic administration. When selecting an appropriate antibiotic, it is important to take into account surgery type and patient's characteristics which would also impact timing of administration and prophylaxis duration. Although surgical AP is significant for avoiding bacterial complications, it is also associated with some drawbacks such as increased antibiotic resistance and development of adverse reactions. Therefore, it is important to assess risks and benefits and select the most appropriate antibiotic regimen before initiating AP.

Clinical prediction models and risk tools for early detection of patients at risk of surgical site infection and surgical wound dehiscence: a scoping review

OBJECTIVE

Despite advances in surgical techniques, intraoperative practice and a plethora of advanced wound therapies, surgical wound complications (SWCs), such as surgical site infection (SSI) and surgical wound dehiscence (SWD), continue to pose a considerable burden to the patient and healthcare setting. Predicting those patients at risk of a SWC may give patients and healthcare providers the opportunity to implement a tailored prevention plan or potentially ameliorate known risk factors to improve patient postoperative outcomes.

METHOD

A scoping review of the literature for studies which reported predictive power and internal/external validity of risk tools for clinical use in predicting patients at risk of SWCs after surgery was conducted. An electronic search of three databases and two registries was carried out with date restrictions. The search terms included 'prediction surgical site infection' and 'prediction surgical wound dehiscence'.

RESULTS

A total of 73 records were identified from the database search, of which six studies met the inclusion criteria. Of these, the majority of validated risk tools were predominantly within the cardiothoracic domain, and targeted morbidity and mortality outcomes. There were four risk tools specifically targeting SWCs following surgery.

CONCLUSION

The findings of this review have highlighted an absence of well-developed risk tools specifically for SSI and/or SWD in most surgical populations. This review suggests that further research is required for the development and clinical implementation of rigorously validated and fit-for-purpose risk tools for predicting patients at risk of SWCs following surgery. The ability to predict such patients enables the implementation of preventive strategies, such as the use of prophylactic antibiotics, delayed timing of surgery, or advanced wound therapies following a procedure.

The Rate of Postoperative Mortality and Renal and Respiratory Complications are Increased in Patients with Extreme Obesity Undergoing Cardiac Surgery - A Retrospective Observational Cohort Study of 8848 Patients

Introduction

The importance of obesity as a potential risk factor in open heart surgery is well known. The epidemic of extreme obesity is an increasing public health concern and raises alerts regarding postoperative complications and mortality in patients undergoing cardiac surgery. The study aimed to analyze the impact of extreme obesity (BMI≥40) on the frequency of postoperative complications, as well as early and delayed mortality compared to patients with a lower body mass.

Materials and Methodology

This retrospective observational cohort study involved patients, over the age of 18, undergoing cardiac surgery with cardiopulmonary bypass at the Cardiac Surgery Department of the Pomeranian Medical University in Szczecin, Poland between January 1st, 2010 and December 31st, 2018. The patients included in the study were allocated into two subgroups depending on the BMI index (Group I BMI≥40 vs Group II BMI<40).

Results

A total of 8848 adult patients of both genders were included. Baseline characteristics for Group I and Group II were mean age 64.07±7.76 vs 65.10±9.68 years (p=0.123), mean BMI 42.13±2.44 vs 28.55±4.23 (p<0.001), with more females in Group I (58.04% vs 29.06%) and more males in Group II (70.94% vs 29.06%), p<0.001. The predicted perioperative risk using the EuroScore Logistics scale was higher in a group with BMI≥40 (p<0.001). Regression analysis with adjustment for confounding factors showed a statistically significant relationship between BMI≥40 and postoperative respiratory failure (OR=1.760, p=0.043), acute kidney injury AKIN2 (OR=2.082, p=0.044) and AKIN3 (OR=2.743, p=0.039). 30-day mortality in the univariate analysis showed a statistically significant relationship, however, after modifying the results with interfering factors, no statistical significance was obtained.

Conclusion

The risk of postoperative acute respiratory failure and acute renal injury was increased in patients with BMI≥40. The probability of 30-day survival of patients after cardiac surgery was much lower in people with extreme obesity, although it was related to the dominant comorbidities. The 10-year survival was comparable in both groups.

[Position statement: surgery and diabetes mellitus (Update 2023)]

This position statement reflects the perspective of the Austrian Diabetes Association concerning the perioperative management of people with diabetes mellitus based on the available scientific evidence. The paper covers necessary preoperative examinations from an internal/diabetological point of view as well as the perioperative metabolic control by means of oral antihyperglycemic and/or insulin therapy.

Surgical Site Infection in Cardiac Surgery

Surgical site infections (SSIs) are one of the most significant complications in surgical patients and are strongly associated with poorer prognosis. Due to their aggressive character, cardiac surgical procedures carry a particular high risk of postoperative infection, with infection incidence rates ranging from a reported 3.5% and 26.8% in cardiac surgery patients. Given the specific nature of cardiac surgical procedures, sternal wound and graft harvesting site infections are the most common SSIs. Undoubtedly, DSWIs, including mediastinitis, in cardiac surgery patients remain a significant clinical problem as they are associated with increased hospital stay, substantial medical costs and high mortality, ranging from 3% to 20%. In SSI prevention, it is important to implement procedures reducing preoperative risk factors, such as: obesity, hypoalbuminemia, abnormal glucose levels, smoking and S. aureus carriage. For decolonisation of S. aureus carriers prior to cardiac surgery, it is recommended to administer nasal mupirocin, together with baths using chlorhexidine-based agents. Perioperative management also involves antibiotic prophylaxis, surgical site preparation, topical antibiotic administration and the maintenance of normal glucose levels. SSI treatment involves surgical intervention, NPWT application and antibiotic therapy.

Incidence and risk factors of surgical site infections after coronary artery bypass grafting surgery in Oman

Background

There is limited information about the incidence and risk factors of surgical site infections (SSIs) after coronary artery bypass (CABG) surgeries in the Omani population.

Aim

To estimate the prevalence and describe possible risk factors of SSIs after CABG surgeries in Oman.

Method

A retrospective nested case-control design was used to screen 596 patients who underwent CABG surgeries over 2 years (2016-2017) in two tertiary hospitals in Oman. The CDC definition for SSIs was used to identify the infected cases.

Results

Prevalence rate of SSIs was 17.4% and 17.5% in 2016 and 2017, respectively. The most isolated microorganism was Gram-positive bacteria (45.2%). Risk factors of SSIs include female gender (OR = 3.2, p < 0.001), diabetes (OR = 5.83, p < 0.001), overweight or obese (OR = 2.14, p < 0.05) and shaving technique [using razor shaving] (OR = 8.4, p < 0.001). Readmission rate for the case group was 44.2%.

Conclusion

The infection rate of SSIs after CABG surgeries in developing countries, such as Oman, is considerably high. There is an urgent need to establish SSIs preventive program at the national level. Frequent and systematic assessment of infection control practices before and after CABG surgeries is fundamental and priority strategy to prevent SSIs.

Performance of a novel risk model for deep sternal wound infection after coronary artery bypass grafting

Clinical prediction models for deep sternal wound infections (DSWI) after coronary artery bypass graft (CABG) surgery exist, although they have a poor impact in external validation studies. We developed and validated a new predictive model for 30-day DSWI after CABG (REPINF) and compared it with the Society of Thoracic Surgeons model (STS). The REPINF model was created through a multicenter cohort of adults undergoing CABG surgery (REPLICCAR II Study) database, using least absolute shrinkage and selection operator (LASSO) logistic regression, internally and externally validated comparing discrimination, calibration in-the-large (CL), net reclassification improvement (NRI) and integrated discrimination improvement (IDI), trained between the new model and the STS PredDeep, a validated model for DSWI after cardiac surgery. In the validation data, c-index = 0.83 (95% CI 0.72–0.95). Compared to the STS PredDeep, predictions improved by 6.5% (IDI). However, both STS and REPINF had limited calibration. Different populations require independent scoring systems to achieve the best predictive effect. The external validation of REPINF across multiple centers is an important quality improvement tool to generalize the model and to guide healthcare professionals in the prevention of DSWI after CABG surgery.

Risk Factors and Outcome of Multidrug-Resistant Infections after Heart Transplant: A Contemporary Single Center Experience

(1) Background: The aim of this study was to assess risk factors for multidrug-resistant/extensively drug-resistant (MDR/XDR) bacterial infections in heart transplant (HT) patients within three months after surgery and its impact on patient outcome. (2) Methods: Retrospective analysis of clinical, hemato-chemical, imaging, treatment and outcome data from 47 heart transplant recipients from January 2016 to December 2018. MDR/XDR infections were compared to non-MDR/XDR and noninfected patients. (3) Results: Most participants were males, median age 51 years: 35 (74.5%) developed an infection after HT; 14 (29.8%) were MDR/XDR infections. Prolonged hospital stay before HT correlated to MDR/XDR infection (p < 0.001). Sequential organ failure assessment (SOFA) score at sampling day was higher in MDR/XDR (p = 0.027). MDR/XDR were mostly blood-stream (BSI) (p = 0.043) and skin-soft tissue (SSTI) (p = 0.047) infections. Gram-negative infections were the most frequent, specifically carbapenem-resistant Klebsiella pneumoniae. Antibiotic therapy duration for MDR/XDR infections was longer (p = 0.057), eradication rate lower (p = 0.083) and hospital stay longer (p = 0.005) but not associated with a worse outcome. (4) Conclusions: MDR/XDR infections affect compromised HT recipients with a history of prolonged hospitalization, causing a lower rate of eradication and increased hospital stay. These frequently present as BSI and SSTI. We emphasize the need to prevent contamination of central venous catheters and the surgical site.

Higher Surgery and Recovery Room Air Pressures Associated with Reduced Surgical Site Infection Risk

BACKGROUND

Incisional surgical site infections (SSIs) following coronary artery bypass grafting (CABG) prolong hospital stays, elevate healthcare costs and increase likelihood of further complications. High air pressure deactivates bacteria and is utilized for commercial food preservation, assuring microbiologically safe pharmaceuticals and sanitizing instruments. However, research on utilizing air pressure deactivation thresholds in surgical and postoperative rooms to reduce rates of SSIs is lacking.

METHODS

A case-control study of 801 CABG patients, 128 SSI cases and 673 controls was conducted from January 1, 2006 through March 31, 2009 in Yerevan, Armenia. Patient and surgery characteristics, air pressure measurements and seasons were selected as independent variables with SSI rates as the outcome. The novel threshold regression analysis was used to determine potential air pressure bacterial deactivation thresholds. A final multivariate logistic regression model adjusted for confounders.

RESULTS

Overall, bacterial deactivation air pressure threshold was 694.2 mmHg, with the presence of infection for higher air pressure values not statistically significant from zero. Individual deactivation thresholds for Staphylococcus epidermidis (threshold = 694.2 mmHg) and Escherichia coli (threshold = 689.2) showed similar patterns. Multivariate logistic regression showed air pressure above the deactivation threshold was highly protective against SSIs with adjOR = 0.27 (p-value = 0.009, 95%CI: 0.10-0.72). Other SSI risk factors included female sex, adjOR = 2.12 (p-value = 0.006, 95%CI: 1.24-3.62), diabetes, adjOR = 2.61 (p-value < 0.001, 95%CI: 1.72-3.96) and longer time on ventilator, adjOdds = 1.01 (p-value = 0.012, 95%CI: 1.00-1.02).

CONCLUSION

Maintaining air pressures in operating and postoperative rooms exceeding bacterial-deactivation thresholds might substantially reduce SSI rates following surgery. Further research should identify specific bacterial-deactivation air pressure thresholds in surgical and postoperative rooms to reduce SSI rates, especially for drug-resistant bacteria.

Epidemiology, Treatment, and Prevention of Nosocomial Bacterial Pneumonia

Septicaemia likely results in high case-fatality rates in the present multidrug-resistant (MDR) era. Amongst them are hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP), two frequent fatal septicaemic entities amongst hospitalised patients. We reviewed the PubMed database to identify the common organisms implicated in HAP/VAP, to explore the respective risk factors, and to find the appropriate antibiotic choice. Apart from methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa, extended-spectrum β-lactamase-producing Enterobacteriaceae spp., MDR or extensively drug-resistant (XDR)-Acinetobacter baumannii complex spp., followed by Stenotrophomonas maltophilia, Chryseobacterium indologenes, and Elizabethkingia meningoseptica are ranked as the top Gram-negative bacteria (GNB) implicated in HAP/VAP. Carbapenem-resistant Enterobacteriaceae notably emerged as an important concern in HAP/VAP. The above-mentioned pathogens have respective risk factors involved in their acquisition. In the present XDR era, tigecycline, colistin, and ceftazidime-avibactam are antibiotics effective against the Klebsiella pneumoniae carbapenemase and oxacillinase producers amongst the Enterobacteriaceae isolates implicated in HAP/VAP. Antibiotic combination regimens are recommended in the treatment of MDR/XDR-P. aeruginosa or A. baumannii complex isolates. Some special patient populations need prolonged courses (>7-day) and/or a combination regimen of antibiotic therapy. Implementation of an antibiotic stewardship policy and the measures recommended by the United States (US) Institute for Healthcare were shown to decrease the incidence rates of HAP/VAP substantially.