Preoperative screening cultures in the identification of staphylococci causing wound and valvular infections in cardiac surgery

Cultures of nasal or presternal swabs form part of the routine preoperative screening of patients on the cardiac surgical ward. During a trial of antibiotic prophylaxis in 314 patients, preoperative isolates of Staphylococcus aureus and coagulase-negative staphylococci were compared with strains associated with postoperative sternal wound breakdown (24 patients) and prosthetic valve endocarditis (3 patients). Morphology, antibiotic sensitivity pattern, plasmid analysis and phage typing were used to differentiate strains. In only three cases of wound infection and one of prosthetic valve endocarditis were pathogenic staphylococci not distinguishable from preoperative isolates. The collection of superficial swabs for this purpose before cardiac surgery is therefore unlikely to be cost effective

Prevention and control of multi-drug-resistant Gram-negative bacteria: recommendations from a Joint Working Party

Multi-drug-resistant (MDR) Gram-negative bacterial infections have become prevalent in some European countries. Moreover, increased use of broad-spectrum antimicrobial agents selects organisms with resistance and, by increasing their numbers, increases their chance of spread. This report describes measures that are clinically effective for preventing transmission when used by healthcare workers in acute and primary healthcare premises. Methods for systematic review 1946–2014 were in accordance with SIGN 501 and the Cochrane Collaboration;2 critical appraisal was applied using AGREEII.3 Accepted guidelines were used as part of the evidence base and to support expert consensus. Questions for review were derived from the Working Party Group, which included patient representatives in accordance with the Patient Intervention Comparison Outcome (PICO) process. Recommendations are made in the following areas: screening, diagnosis and infection control precautions including hand hygiene, single-room accommodation, and environmental screening and cleaning. Recommendations for specific organisms are given where there are species differences. Antibiotic stewardship is covered in a separate publication

Association between peri-operative angiotensin-converting enzyme inhibitors and angiotensin-2 receptor blockers and acute kidney injury in major elective non-cardiac surgery: a multicentre, prospective cohort study

The peri-operative use of angiotensin-converting enzyme inhibitors or angiotensin-2 receptor blockers is thought to be associated with an increased risk of postoperative acute kidney injury. To reduce this risk, these agents are commonly withheld during the peri-operative period. This study aimed to investigate if withholding angiotensin-converting enzyme inhibitors or angiotensin-2 receptor blockers peri-operatively reduces the risk of acute kidney injury following major non-cardiac surgery. Patients undergoing elective major surgery on the gastrointestinal tract and/or the liver were eligible for inclusion in this prospective study. The primary outcome was the development of acute kidney injury within seven days of operation. Adjusted multi-level models were used to account for centre-level effects and propensity score matching was used to reduce the effects of selection bias between treatment groups. A total of 949 patients were included from 160 centres across the UK and Republic of Ireland. From this population, 573 (60.4%) patients had their angiotensin-converting enzyme inhibitors or angiotensin-2 receptor blockers withheld during the peri-operative period. One hundred and seventy-five (18.4%) patients developed acute kidney injury; there was no difference in the incidence of acute kidney injury between patients who had their angiotensin-converting enzyme inhibitors or angiotensin-2 receptor blockers continued or withheld (107 (18.7%) vs. 68 (18.1%), respectively; p = 0.914). Following propensity matching, withholding angiotensin-converting enzyme inhibitors or angiotensin-2 receptor blockers did not demonstrate a protective effect against the development of postoperative acute kidney injury (OR (95%CI) 0.89 (0.58–1.34); p = 0.567)

Thermographic mapping of the abdomen in healthy subjects and patients after enterostoma

Objective: Heat is a sign and symptom of surgical wound infection in wound assessment criteria but there is currently no diagnostic tool being used in clinical practice to assess the skin temperature of surgical wounds. Using thermal imaging, the objective of this study was to map the temperature of the healing surgical wound and to provide confirmatory data of: a) optimum IR imaging distance from skin temperature target field of view (FOV) b) body composition effects on abdominal skin surface temperature readings c) thermal mapping characteristics of infected versus non-infected wounds post stoma-closure. Method: The abdominal skin surface temperature of healthy, afebrile subjects was measured under controlled, ambient conditions in a small (240cm × 320cm) clinical room. Subject standing positions were 30cm, 60cm and 100cm from the IR camera. Abdominal skin surface temperature and thermal imaging maps were acquired in a population of surgical patients before and after closure of enterostoma. Results: Subjects (30) aged 19-52 (median=29) years were recruited. At a distance of 100cm, each of nine anatomical regions showed a decrease in mean temperature as BMI increased. Subjects with BMI >25 had lower mean abdominal temperatures. Statistically significant differences were observed for right hypochondrium (p=0.022), left lumbar region (p=0.009), right lumbar region (p=0.010) and the umbilical region (p=0.021). Half of patients (5/10) developed surgical wound infection. Conclusion: Within the operating distances investigated, no significant effect on abdominal temperature readings was observed. With increasing BMI, lower abdominal temperatures were noted. The thermal pattern of abdominal surgical wounds reveals some differences between the healing and infected wound. Healing wounds showed changes in the thermal 'map'; an increase in temperature on the first post-operative day, and 'warming' over the subsequent five days. 'Cold spots' emerged on the thermogram of the surgical wounds which subsequently were shown to be infected. Within the setting of a clinical environment, distances up to 100cm did not significantly alter skin temperature readings within the FOV. There is a suggestion that body composition influences skin temperature. Infected surgical wounds appear 'colder' than healing wounds. Declaration of interest: The authors have no conflict or interest.The work was supported by a grant from the SingHealth Foundation.</p