Colonization resistance against multi-drug-resistant bacteria: a narrative review.

Colonization resistance by gut microbiota is a fundamental phenomenon in infection prevention and control. Hospitalized patients may be exposed to multi-drug-resistant bacteria when hand hygiene compliance among healthcare workers is not adequate. An additional layer of defence is provided by the healthy gut microbiota, which helps clear the exogenous bacteria and acts as a safety net when hand hygiene procedures are not followed. This narrative review focuses on the role of the gut microbiota in colonization resistance against multi-drug-resistant bacteria, and its implications for infection control. The review discusses the underlying mechanisms of colonization resistance (direct or indirect), the concept of resilience of the gut microbiota, the link between the antimicrobial spectrum and gut dysbiosis, and possible therapeutic strategies. Antimicrobial stewardship is crucial to maximize the effects of colonization resistance. Avoiding unnecessary antimicrobial therapy, shortening the antimicrobial duration as much as possible, and favouring antibiotics with low anti-anaerobe activity may decrease the acquisition and expansion of multi-drug-resistant bacteria. Even after antimicrobial therapy, the resilience of the gut microbiota often occurs spontaneously. Spontaneous resilience explains the existence of a window of opportunity for colonization of multi-drug-resistant bacteria during or just after antimicrobial therapy. Strategies favouring resilience of the gut microbiota, such as high-fibre diets or precision probiotics, should be evaluated.

High incidence of postoperative infections after pancreaticoduodenectomy: A need for perioperative anti-infectious strategies.

OBJECTIVES: Postoperative infections occur frequently after pancreaticoduodenectomy, especially in patients with bile colonization. Recommendations for perioperative anti-infectious treatment are lacking, and clinical practice is heterogenous. We have analyzed the effects of bile colonization and antibiotic prophylaxis on postoperative infection rates, types and therapeutic consequences. METHODS: Retrospective observational study in patients undergoing pancreaticoduodenectomy with intraoperative bile culture. Data on postoperative infections and non-infectious complications, bile cultures and antibiotic prophylaxis adequacy to biliary bacteria were collected. RESULTS: Among 129 patients, 53% had a positive bile culture and 23% had received appropriate antibiotic prophylaxis. Postoperative documented infection rate was over 40% in patients with or without bile colonization, but antibiotic therapy was more frequent in positive bile culture patients (77% vs. 57%, P=0,008). The median duration of antibiotic therapy was 11 days and included a broad-spectrum molecule in 42% of cases. Two-thirds of documented postoperative infections involved one or more bacteria isolated in bile cultures, which was associated with a higher complication rate. While bile culture yielded Gram-negative bacilli (57%) and Gram-positive cocci (43%), fungal microorganisms were scarce. Adequate preoperative antibiotic prophylaxis according to bile culture was not associated with reduced infectious or non-infectious complication rates. CONCLUSION: Patients undergoing pancreaticoduodenectomy experience a high rate of postoperative infections, often involving bacteria from perioperative bile culture when positive, with no preventive effect of an adequate preoperative antibiotic prophylaxis. Increased postoperative complications in patients with bile colonization may render necessary a perioperative antibiotic treatment targeting bile microorganisms. Further prospective studies are needed to improve the anti-infectious strategy in these patients.

Spontaneous decolonization during hospitalization in intensive care unit patients colonized by extended-spectrum beta-lactamase-producing Enterobacterales.

This study aimed to analyse the frequency of occurrence of spontaneous decolonization in intensive care unit patients colonized by extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E) in order to assess the added value of continuing weekly ESBL-E rectal carriage screening in these patients. In total, 49,468 weekly rectal screening samples taken from 20,846 patients over 12 years were included. Among the 4280 ESBL-E carriers, only 109 patients (2.5%) could be considered decolonized at the end of their hospitalization with at least three consecutive negative samples. Overall, 7957 samples (16.1%) were requested for patients already identified as ESBL-E carriers. Avoiding unnecessary weekly screening following positive ESBL-E colonization results could decrease nursing and laboratory work loads.

An educational intervention about the classification of penicillin allergies: effect on the appropriate choice of antibiotic therapy in pregnant women.

BACKGROUND: Most pregnant women who self-report penicillin allergy are not truly penicillin-allergic and this misunderstanding often leads to administration of inappropriate antibiotic therapy. Decision algorithms have been developed to guide antibiotic selection but major discrepancies have been reported between guidelines and clinical practice. We aimed to optimize the prescription of antibiotics for pregnant women who self-reported penicillin allergy, using an educational intervention about the classification of penicillin allergies that targeted gynecologists, anesthesiologists and midwives. METHODS: This quasi-experimental study assessed the effect of an educational intervention about the classification of penicillin allergy. For six months, a combination of two strategies was used, namely dissemination of printed educational materials and group education. The principal study endpoint was the appropriateness of the antibiotic therapy, defined in advance for each level of allergic risk. RESULTS: The pre-intervention phase included 903 women; one year after its conclusion, the post-intervention phase began and included 892 women. The prevalence of self-reported penicillin allergy was stable over the two periods (6.8% before vs 5.4% after, P=0.24). The clinical classification of penicillin allergies was more often used after the educational intervention (68% vs 100%, P<0.001). The appropriateness of the antibiotic therapy prescribed to self-reported penicillin allergic-women increased significantly between the two periods, from 5/29 (17.2%) to 18/27 (66.7%, P<0.001). CONCLUSION: An educational intervention about penicillin allergy classification was associated with an improvement in the choice of appropriate antibiotic therapy among women who had reported penicillin allergy.

Risk factors for acquisition of OXA-48-producing Klebsiella pneumonia among contact patients: a multicentre study.

BACKGROUND: Cohorting carbapenemase-producing Enterobacteriaceae (CPE) carriers during hospitalization limits in-hospital spreading. AIM: To identify risk factors for CPE acquisition among contacts of an index patient in non-cohorted populations. METHODS: A multicentre retrospective matched case-control study was conducted in five hospitals. Each contact patient (case) who acquired Klebsiella pneumoniae (KP)-OXA-48 from an index patient was compared to three contact (controls) with the same index patients matched with hospitalization in the same unit and similar exposure times. FINDINGS: Fifty-one secondary cases and 131 controls were included. By univariate analysis, exposure time (odds ratio: 1.06; 95% confidence interval: 1.02-1.1; P = 0.006), concomitant infection at admission (3.23; 1.42-7.35; P = 0.005), antimicrobial therapy within the last month before hospitalization (2.88; 1.34-6.2; P = 0.007), antimicrobial therapy during the exposure time (5.36; 2.28-12.6; P < 0.001), use of at least one invasive procedure (2.99; 1.25-7.15; P = 0.014), number of invasive procedures (1.52; 1.05-2.19; P = 0.025), and geographical proximity (2.84; 1.15-7.00; P = 0.023) were associated with CPE acquisition. By multivariate analysis, antimicrobial therapy during the exposure time (odds ratio: 6.36; 95% confidence interval: 2.46-16.44; P < 0.001), at least one invasive procedure (2.92; 1.04-8.17; P = 0.041), and geographical proximity (3.69; 1.15-11.86; P = 0.028) were associated with acquisition. CONCLUSION: In this study, geographical proximity, invasive procedure, and antimicrobial therapy during exposure time were significantly associated with KP-OXA-48 acquisition.