Cefuroxime versus cefazolin as prophylaxis in vascular surgery

Risk Factors for Wound Infections after Vascular Surgery: Kuwait Experience

INTRODUCTION

Wound infections represent a serious complication after vascular surgery particularly after vascular reconstructive procedures. We aimed to identify risk factors predisposing patients to these complications.

METHODS

This was a retrospective review of open vascular surgical procedures performed between April 2014 and March 2019 in Kuwait. Patient demographics, procedures performed and their indications, and post-operative outcomes were collected and analyzed. Patients with pre-operative active infections were excluded from the analysis. Statistical analysis was performed, and odds ratios (ORs) and relative risks were calculated for the outcomes of interest. Fisher's exact test and two-tailed t test were used where appropriate.

RESULTS

391 patients were identified. The majority (54%) presented with chronic limb threatening ischemia. The mean age was 58 (±10) years, with a male predominance (76%). Wound infection occurred in 53 (14%) patients. The most commonly isolated organism was Staphylococcus aureus (47%). Diabetes (OR 8.03, 95% CI: 1.9142-33.7439, p = 0.0044), hypertension (OR 2.38, 95% CI: 1.2960-4.3684, p = 0.0052), ischemic heart disease (OR 2.30, 95% CI: 1.4349-4.6987, p = 0.0016), hyperlipidemia (OR 2.12, 95% CI: 1.0305-4.3620, p = 0.0412), and chronic renal failure (OR 2.55, 95% CI: 1.0181-6.4115, p = 0.0457) were all found to be significantly associated with the development of post-operative wound infections in vascular surgery patients.

CONCLUSION

Diabetes, hypertension, ischemic heart disease, hyperlipidemia, and chronic renal failure were associated with post-operative wound infections. Anticipation of wound complications in patients with these risk factors may aid early diagnosis and treatment.

Shortage of essential antimicrobials: a major challenge to global health security

The lack of access to safe and effective antimicrobials for human populations is a threat to global health security and a contributor to the emergence and spread of antimicrobial resistance (AMR). The increasingly common shortages of antimicrobials are an additional threat to the emergence of AMR. While the threat of such drug shortages is most acutely experienced in low-income and middle-income settings, their consequences impact the quality and effectiveness of antimicrobials worldwide. Furthermore, there is a need for robustly conducted studies examining the impact of these increasingly prevalent shortages on patient outcomes and on the emergence and spread of AMR. In this review, we have mapped common drivers for antimicrobial shortages and propose strategies for rethinking the regulation, supply and pricing of antimicrobials to secure their sustainable access across diverse healthcare systems and to help minimise the unintended consequences of weak and ineffective supply chains. Greater government involvement in antimicrobial manufacture and supply is essential to ensure no one is left behind. Dedicated demand systems need to be developed for antimicrobials which take into consideration evolving AMR patterns, burden of diseases, pandemic events and supply and demand issues and facilitate implementation of strategies to address them. Interventions, ranging from advocacy and forecasting to public–private collaborations, new economic models and international consortia working across countries and supply chains, will help assure access to safe and effective antimicrobials to all populations around the globe and ensure that shortages no longer contribute to AMR.

Less-invasive saphenous harvest

Vascular and cardiovascular surgeons, having only recently been introduced to less-invasive techniques of saphenous vein harvest and in situ preparation, are embracing these new technologies with cautious enthusiasm. Although the available data are limited, with few prospective randomized trials, less-invasive methods of saphenous vein harvest seem to result in reduced wound complications, improved patient satisfaction, and decreased hospital LOS. The most important but least well defined variable is the effect of harvesting technique on graft patency. Concerns that excess traction and manipulation of the vein during less-invasive harvesting techniques may compromise patency have limited the wide adoption of these techniques. Although an increase in the need for vein repair with 7-0 sutures was reported in one series, limited histologic studies have not shown injury at the cellular level. Patency data for endovascular-assisted, less-invasive, in situ bypass procedures have demonstrated equivalent intermediate results, but less-invasive saphenous vein harvest has limited follow-up data available. Before these less-invasive techniques can be fully embraced, intermediate and long-term patency data must be critically analyzed. If the preliminary impressions of decreased morbidity and hospital LOS are supported by future trials, these savings will certainly eclipse the costs associated with prolonged operating room use and disposable instrumentation. The variety of instruments available and the preponderance of disposables in the market attest to the newness of the field. Although mechanical retraction devices predominate, carbon dioxide insufflation has been used successfully. As the techniques and instrumentation for saphenous harvest are refined, reusable instrumentation will likely play a more prominent role and result in additional cost savings.

A comparison of teicoplanin versus cephradine plus metronidazole in the prophylaxis of post-operative infection in vascular surgery

A total of 272 patients were enrolled into this prospective, unblinded, randomized comparison of single-dose teicoplanin vs three doses of cephradine plus metronidazole as prophylaxis for vascular surgery at St James's and Seacroft Hospitals, Leeds, UK. In all, 71.3% of patients (194/272) were enrolled at St James's University Hospital. Patients received either a single dose of teicoplanin, 6 mg/kg i.v., or cephradine, 1 g i.v. with metronidazole, 1 g rectally, at induction of anaesthesia followed by two further 1 g doses of cephradine and metronidazole 8 and 16 hours later. There were 136 patients in each treatment group. The most common operations were femoropopliteal grafts (96) and aortic aneurysm repairs (47). In the 'intention-to-treat' analysis, primary wound infections were seen in 4.4% of patients (6/136) receiving teicoplanin and 5.9% of patients (8/136) receiving cephradine plus metronidazole (95% CI -6.7%, +3.8%). Other disturbances to wound healing occurred in 23 patients (11 in the teicoplanin and 12 in the cephradine plus metronidazole group). Secondary respiratory tract infections occurred in 17 patients (8 receiving teicoplanin and 9 receiving cephradine plus metronidazole). In the evaluable patients analysis, primary wound infections occurred in 3.5% of patients (4/114) receiving teicoplanin and 5.1% of patients (6/117) receiving cephradine plus metronidazole. Staphylococcus aureus and Proteus sp. were the most common pathogens in primary wound infections. Despite the absence of Gram-negative cover in the teicoplanin group, Gram-negative infections occurred more often in the cephradine plus metronidazole group. Surgery of the lower extremities carried the highest risk of post-operative infection. Rates of infection were significantly higher at Seacroft Hospital (P = 0.001), and significantly higher for cephradine plus metronidazole between the two hospitals (P = 0.0008). Adverse events occurred in 40 patients receiving teicoplanin (29.4%) and 39 patients receiving cephradine plus metronidazole (28.7%). In 19 patients receiving teicoplanin (14%) and 15 receiving cephradine plus metronidazole (11%) these events were considered to be related to the study drugs. The most often reported events were infections, cardiac events and vascular phenomena (haematoma or emboli). Marked changes in haematological parameters and liver function tests were noted seven days after operation in patients in each treatment group, but these resolved quickly as the effects of the operation subsided. ESR remained elevated in both groups at the six-month follow-up assessment. It is concluded from this two-centre study that a single dose of teicoplanin shows similar efficacy to a three-dose regimen of cephradine plus metronidazole as prophylaxis for wound infection in vascular surgery. Both regimens were well tolerated, and there was an equal incidence of adverse events in the two regimens, which reflected the poor general health status of this elderly study population.

beta-Lactamase-mediated inactivation and efficacy of cefazolin and cefmetazole in Staphylococcus aureus abscesses

12694668 Clinical reports and animal models have demonstrated that cefazolin may have decreased efficacy against some strains of Staphylococcus aureus because of type A beta-lactamase-mediated hydrolysis. We sought to measure biologically active cefazolin concentrations within abscesses with high concentrations of S. aureus and compare the concentrations with those of cefmetazole, a beta-lactamase-stable cephamycin. A type A beta-lactamase-producing strain of S. aureus with a demonstrated inoculum effect against cefazolin (MIC at an inoculum of 5 x 10(5) CFU/ml, 1.0 micrograms/ml; MIC at an inoculum of 5 x 10(7) CFU/ml, 32.0 micrograms/ml) but not cefmetazole (MICs at inocula of 5 x 10(5) and 5 x 10(7) CFU/ml, 2.0 micrograms/ml) was used. Cefazolin or cefmetazole (100 mg/kg of body weight every 8 h for 8 days) was administered to rabbits with infected tissue cages. No differences in the concentrations of the two drugs in the uninfected tissue cages were observed. Higher concentrations of cefmetazole than cefazolin were found in infected tissue cages at day 3 (5.9 +/- 0.7 versus 2.2 +/- 0.3 micrograms/ml; P < 0.01), day 5 (9.1 +/- 2.6 versus 3.6 +/- 0.7 micrograms/ml; P = 0.02), and day 8 (9.4 +/- 1.4 versus 4.8 +/- 0.9 micrograms/ml; P = 0.01) after infection. Cefazolin and cefmetazole were equally effective in reducing the bacterial concentration in the abscess. In vitro experiments demonstrated greater cefazolin than cefmetazole degradation by S. aureus, but the differences were greater in serum than in abscess fluid supernatants. We conclude that abscess cefazolin concentrations are diminished by type A beta-lactamase-producing S. aureus, but this did not affect drug efficacy in this model.