[Enterococci and surgical site infections : Causal agent or harmless commensals?]

Epidemiology of vancomycin-resistant enterococci in the United Arab Emirates: a retrospective analysis of 12 years of national AMR surveillance data

INTRODUCTION

Enterococci are usually low pathogenic, but can cause invasive disease under certain circumstances, including urinary tract infections, bacteremia, endocarditis, and meningitis, and are associated with peritonitis and intra-abdominal abscesses. Increasing resistance of enterococci to glycopeptides and fluoroquinolones, and high-level resistance to aminoglycosides is a concern. National antimicrobial resistance (AMR) surveillance data for enterococci from the Middle East and North Africa (MENA) and the Gulf region is scarce.

METHODS

A retrospective 12-year analysis of N = 37,909 non-duplicate diagnostic Enterococcus spp. isolates from the United Arab Emirates (UAE) was conducted. Data was generated by routine patient care during 2010-2021, collected by trained personnel and reported by participating surveillance sites to the UAE National AMR Surveillance program. Data analysis was conducted with WHONET.

RESULTS

Enterococcus faecalis was the most commonly reported species (81.5%), followed by Enterococcus faecium (8.5%), and other enterococci species (4.8%). Phenotypically vancomycin-resistant enterococci (VRE) were found in 1.8% of Enterococcus spp. isolates. Prevalence of VRE (%VRE) was highest for E. faecium (8.1%), followed by E. faecalis (0.9%). A significant level of resistance to glycopeptides (%VRE) for these two species has been observed in the majority of observed years [E. faecalis (0-2.2%), 2010: 0%, 2021: 0.6%] and E. faecium (0-14.2%, 2010: 0%, 2021: 5.8%). Resistance to fluoroquinolones was between 17 and 29% (E. faecalis) and was higher for E. faecium (between 42 and 83%). VRE were associated with higher patient mortality (RR: 2.97), admission to intensive care units (RR: 2.25), and increased length of stay (six excess inpatient days per VRE case), as compared to vancomycin-susceptible Enterococcus spp.

DISCUSSION

Published data on Enterococcus infections, in particular VRE-infections, in the UAE and MENA region is scarce. Our data demonstrates that VRE-enterococci are relatively rare in the UAE, however showing an increasing resistance trend for several clinically important antibiotic classes, causing a concern for the treatment of serious infections caused by enterococci. This study also demonstrates that VRE were associated with higher mortality, increased intensive care unit admission rates, and longer hospitalization, thus poorer clinical outcome and higher associated costs in the UAE. We recommend the expansion of current surveillance techniques (e.g., local VRE screening), stricter infection prevention and control strategies, and better stewardship interventions. Further studies on the molecular epidemiology of enterococci are needed.

Enterococcal pyogenic liver abscesses: high risk of treatment failure and mortality

Enterococci are the most frequent gram-positive bacteria recovered from pyogenic liver abscesses (PLA). This study aims to analyze the impact of the presence of Enterococcus spp. on PLA outcome. We retrospectively analyzed the characteristics and outcome of all PLA cases in which Enterococcus spp. was isolated between January 2010 and September 2019 in a French university hospital and compared them to PLA without Enterococcus spp. Enterococci were recovered from 68 of the 359 (19%) PLA cases. Among the 78 isolates, Enterococcus faecalis (n = 37, 47.7%) and Enterococcus faecium (n = 32, 41%) were the most frequent. Enterococcal PLA were more often of biliary origin (79.4% versus 54.6%, p < 0.001) or post-surgical (35.3% versus 18.6%, p = 0.004). Multivariate analysis showed an independent association between the isolation of Enterococcus spp. and 3-month mortality (HR 2.51, p = 0.011), primary failure (HR 2.15, p = 0.006), but not with relapses (HR 0.86, p = 0.739). In the subgroup of enterococcal PLA, portal vein thrombosis was the only factor significantly associated with 3-month mortality (univariate HR 3.45, p = 0.023) or primary treatment failure (multivariate, HR 4.02, p = 0.006). Enterococcus spp. identification in a PLA is associated with a higher mortality and primary treatment failure.

Hygiene in der Dermatologie: multiresistente gram-negative Stäbchen (MRGN) und Vancomycin-resistente Enterokokken (VRE)

Bakterielle Besiedlungen von Haut und Wunden sowie Infektionen mit Problemkeimen spielen in der Dermatologie eine wichtige Rolle. Neben Methicillin-resistenter Staphylococcus aureus (MRSA) finden sich auch zunehmend MRGN und VRE bei Wund- und Weichteilinfektionen. Da sowohl für multiresistente gram-negative Stäbchen (MRGN) als auch Vancomycin-resistente Enterokokken (VRE) das Haupt-Reservoir der menschliche Darm ist, ist eine Sanierung nicht möglich. Daher ist das Ziel, bei diesen beiden multiresistenten Erregerarten durch Prävention bei Risikopatienten und geeignete Hygiene-Maßnahmen eine Reduktion in zusätzlichen Reservoiren wie bspw. chronischen Wunden zu erreichen sowie durch richtigen Einsatz von Antibiotika eine weitere Zunahme von MRGN- und VRE-Inzidenzen zu verhindern. Aus diesem Grund ist bei der Infektionsprävention ein besonderer Fokus auf das Hygienemanagement zu legen. Dieses soll praxisnah, effizient und nachvollziehbar, damit also auch vermittelbar sein. Die Antibiotikastrategie soll so ausgestaltet sein, dass die Selektion resistenter Erreger möglichst verhindert wird. Dies gilt gleichermaßen für das Krankenhaus wie auch das ambulante Umfeld von Patienten.

Snapshot of resistance and virulence features in ESCAPE strains frequently isolated from surgical wound infections in a Romanian hospital

Background: The aim of this study was to investigate the phenotypic features (adherence, biofilm formation, virulence, antibiotic susceptibility) and the genetic background of antibiotic resistance in nosocomial ESCAPE strains consecutively isolated from surgical wound infections in hospitalized patients.

Methods: 86 bacterial strains consecutively isolated from various wound infections were analysed by their antibiotic resistance (antibiotic susceptibility testing and PCR for certain antibiotic resistance genes), virulence, biofilm formation and cellular adherence.

Results: The bacterial isolates were identified as: Enterobacterales (n = 39) including Escherichia coli (n = 9), Klebsiella pneumoniae (n = 14) Proteus mirabilis (n = 7), followed by Staphylococcus aureus (n = 26) and Enterococcus faecalis (n = 20). Compared to other isolates, S. aureus strains exhibited the highest capacity to produce soluble virulence factors and to develop biofilms in vitro, with significant differences between methicillin resistant and methicillin susceptible isolates. Among enterobacterial isolates, K. pneumoniae strains expressed the highest capacity to develop biofilms. The assessment of bacterial adherence to HeLa cells revealed that all bacterial strains adhered to the cellular substrata, showing various adherence patterns. E. faecalis strains exhibited a low soluble virulence factors profile, a lower capacity to adhere to epithelial cells and to develop biofilms.

Conclusions: The present study could contribute to the understanding of the pathology of infected wounds, depending on the etio-logical agents, providing data with positive impact on the therapeutic management of surgical wounds infections.

Is There an Association between Intra-Operative Detection of Pathogens in Subcutaneous Tissue and Surgical Site Infections? Results from a Prospective Study

Background: Surgical site infections (SSIs) are a common complication in visceral surgery. Pathogens causing SSIs vary depending on the type of surgery. Patients and Methods: Within the scope of the Reduction of Postoperative Wound Infections by Antiseptica (RECIPE) trial we analyzed the pathogens cultured in intra-operative, subcutaneous swabs and in swabs from SSI in a single-center, prospective, randomized controlled study. Definition of SSI complied with the criteria of the U.S. Centers for Disease Control and Prevention (CDC). Results: The overall rate of SSI was 28.2% in 393 patients. Colorectal surgery was performed in 68.2% of elective laparotomies. Pathogens were more often detected in intra-operative subcutaneous swabs in patients who developed SSIs than in patients who did not develop SSIs (64.4% vs. 38.0%; p < 0.001). Enterococci were found in 29.1% of intra-operative swabs in patients with SSIs, followed by Escherichia coli in 15.5%. A higher rate of Enterococcus faecium was found in patients with anemia versus those without anemia (9.2% vs. 2.3%; p = 0.006) and in patients who smoked versus those who did not (11.8% vs. 3.6%; p = 0.008). A positive subcutaneous swab (odds ratio [OR], 2.51; 95% confidence interval [CI], 1.47-4.29; p = 0.001), pre-operative anemia (OR, 1.84; 95% CI, 1.08-3.13; p = 0.016), and renal insufficiency (OR, 2.15; 95% CI, 1.01-4.59; p = 0.048) were risk factors for SSIs. Conclusions: There is an association between the intra-operative detection of pathogens in subcutaneous tissue and the development of SSIs in visceral surgery. The most prevalent pathogens causing SSIs were enterococci and Escherichia coli. More efforts are justified to reduce subcutaneous colonization with pathogens, for example by using intra-operative wound irrigation with polyhexanide solution. This trial is registered at www.ClinicalTrials.gov (ID: NCT04055233).

Surgical Revision Promotes Presence of Enterococcus spp. in Abdominal Superficial Surgical Site Infections

BACKGROUND

Superficial surgical site infections (SSSIs) are a major reason for morbidity after abdominal surgery. Microbiologic isolates of SSSIs vary widely geographically. Therefore, knowledge about the specific bacterial profile is of paramount importance to prevent SSSI.

METHODS

We performed a subgroup analysis of the microbiological isolates from patients with SSSI after abdominal surgery that were included in our institutional wound register. We aimed at identifying predominant strains as well as risk factors that would predispose for SSSI with certain bacteria.

RESULTS

A total of 494 patients were eligible for analysis. Of those 313 had received wound swaps, with 268 patients yielding a bacterial isolate. Enterobacterales (31.7%) and Enterococcus spp. (29.5%) were found as main bacteria in SSSI, with 62.3% of the wounds being polymicrobial. As risk factors for changes in bacterial isolates, we identified operative revision (OR 3.032; 95%CI 1.734-5.303) in multivariate analysis. Enterococcus spp. showed a significant increase in patients after revision surgery (p<0.001). Antibiotic therapy was neither influential on bacterial changes nor on the presence of Enterococcus spp. in SSSI.

CONCLUSION

Our study accentuates the high frequency of Enterococcus spp. in SSSI after abdominal surgery, while identifying surgical revision as major risk factor. The results urge vigilance in the treatment of patients with surgical revisions to include Enterococcus spp. in the prevention and treatment strategies.

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Background

We aimed to determine the prevalence and risk factors of surgical site infection (SSI) after cesarean delivery (CD) in a rural area in China.

Methods

We identified 155 patients with incisional and organ/space SSIs by International Classification of Disease codes and matched them with 465 patients (controls) in a time-matched retrospective quality assurance analysis. Multiple logistic regression analyses were performed to examine the risk factors for SSI: the work-years of providers, the number of antenatal care (ANC) visits, CD after labor, positive discharge culture, postoperative C-reactive protein (CRP) levels and fever.

Results

and discussion: During the study, 155 women with SSI were identified among the 8640 patients who delivered by CD. The incidence of SSIs was 179 per 10 000patients (95%CI: 151–207 per 10 000 patients). The total duration of hospitalization in patients with SSI was 14.49 ± 8.68 days compared with 7.96 ± 2.35 days in patients with no SSI (P < 0.01). Multiple logistic regression analysis showed that the work-years of providers (odds ratio [OR] = 3.729, 95% confidence interval [CI]: 1.463–9.501, p = 0.006), irregular ANC visits (OR = 3.245, 95% CI: 1.264–8.329, p = 0.028), CD after labor (OR = 2.545, 95% CI: 0.935–6.926, p = 0.020), postoperative CRP level (OR = 2.545, 95% CI: 0.935–6.926, p = 0.016) and a positive discharge culture (OR = 2.954, 95% CI: 0.305–28.643, p = 0.019) were positively associated with SSI. However, the rates of maternal request (OR = 0.186, 95% CI: 0.065–0.535, p = 0.002) and postoperative fever (OR = 0.208, 95% CI: 0.087–0.494, p = 0.001) were negatively related to SSI.

Conclusions

Special attentions should be paid to CD patients who had irregular ANC visits, attempted labor, a positive discharge culture, higher CRP levels and fever after surgery, who had a greater risk of SSI.

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The incidence of SSIs was 179 per 10 000 patients (95%CI: 151–207).

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Risk factors of SSIs included: irregular ANC visits, a positive discharge culture.

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Higher CRP levels and fever after surgery had a greater risk of SSI.

Interplay between ESKAPE Pathogens and Immunity in Skin Infections: An Overview of the Major Determinants of Virulence and Antibiotic Resistance

The skin is the largest organ in the human body, acting as a physical and immunological barrier against pathogenic microorganisms. The cutaneous lesions constitute a gateway for microbial contamination that can lead to chronic wounds and other invasive infections. Chronic wounds are considered as serious public health problems due the related social, psychological and economic consequences. The group of bacteria known as ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter sp.) are among the most prevalent bacteria in cutaneous infections. These pathogens have a high level of incidence in hospital environments and several strains present phenotypes of multidrug resistance. In this review, we discuss some important aspects of skin immunology and the involvement of ESKAPE in wound infections. First, we introduce some fundamental aspects of skin physiology and immunology related to cutaneous infections. Following this, the major virulence factors involved in colonization and tissue damage are highlighted, as well as the most frequently detected antimicrobial resistance genes. ESKAPE pathogens express several virulence determinants that overcome the skin's physical and immunological barriers, enabling them to cause severe wound infections. The high ability these bacteria to acquire resistance is alarming, particularly in the hospital settings where immunocompromised individuals are exposed to these pathogens. Knowledge about the virulence and resistance markers of these species is important in order to develop new strategies to detect and treat their associated infections.

Treatment with Ceftriaxone in Complicated Diverticulitis Increases the Incidence of Intra-Abdominal Enterococcus faecium Detection

Background: Complicated diverticulitis of the sigmoid colon typically is treated by resection after initial antibiotic treatment. Third-generation cephalosporins are the drugs of choice but are not effective against enterococci and can induce colonic colonization by Enterococcus faecium within hours. Infections caused by enterococci, especially E. faecium, are difficult to treat but should be considered in the strategic treatment planning of hospital-acquired peritonitis (e.g., anastomotic leakage), especially in immunocompromised patients. Methods: To determine whether the duration of pre-operative ceftriaxone treatment in complicated diverticulitis increases the incidence of intra-abdominal E. faecium detection, we analyzed all patients operated on for diverticulitis of the sigmoid colon in our department between 2008 and 2016. Results: Analyzing 516 resections performed for complicated diverticulitis, we found that E. faecium generally was detected intra-abdominally more often in the group that underwent longer pre-operative ceftriaxone treatment (≥ 4 days). During primary resection, E. faecium was detected in 2.7%, 11.1%, and 37.0% cases in the group undergoing immediate operation, 1-3 days of antibiotic treatment, and ≥4 days of antibiotic treatment, respectively. Enterococcus faecium was detected in 0, 25.0%, and 70.6% of surgical revisions and 28.6%, 14.3%, and 56.0%, respectively, of incisional surgical site infections with identified pathogens. A multivariable analysis discovered anastomotic leakage and antibiotic treatment lasting ≥4 days to be independent risk factors for intra-abdominal isolation of E. faecium. Conclusion: A ceftriaxone treatment ≥4 days led to a higher incidence of intra-abdominal E. faecium. Our data further suggested that empiric coverage of E. faecium in the treatment of hospital-acquired peritonitis could be beneficial after a long duration of ceftriaxone treatment.