Nosocomial bloodstream infections in neurosurgery: a 10-year analysis in a center with high antimicrobial drug-resistance prevalence

Dual-targeting tigecycline nanoparticles for treating intracranial infections caused by multidrug-resistant Acinetobacter baumannii

Multidrug-resistant (MDR) Acinetobacter baumannii (A. baumannii) is a formidable pathogen responsible for severe intracranial infections post-craniotomy, exhibiting a mortality rate as high as 71%. Tigecycline (TGC), a broad-spectrum antibiotic, emerged as a potential therapeutic agent for MDR A. baumannii infections. Nonetheless, its clinical application was hindered by a short in vivo half-life and limited permeability through the blood-brain barrier (BBB). In this study, we prepared a novel core-shell nanoparticle encapsulating water-soluble tigecycline using a blend of mPEG-PLGA and PLGA materials. This nanoparticle, modified with a dual-targeting peptide Aβ11 and Tween 80 (Aβ11/T80@CSs), was specifically designed to enhance the delivery of tigecycline to the brain for treating A. baumannii-induced intracranial infections. Our findings demonstrated that Aβ11/T80@CSs nanocarriers successfully traversed the BBB and effectively delivered TGC into the cerebrospinal fluid (CSF), leading to a significant therapeutic response in a model of MDR A. baumannii intracranial infection. This study offers initial evidence and a platform for the application of brain-targeted nanocarrier delivery systems, showcasing their potential in administering water-soluble anti-infection drugs for intracranial infection treatments, and suggesting promising avenues for clinical translation.

Antibiotic Use in Lateral Skull Base Surgery: A Survey of the North American Skull Base Society

Objectives Antibiotic use in lateral skull base surgery (LSBS) has not been thoroughly investigated in the literature. There is wide variability in antibiotic use and insufficient data to guide management. This study aims to describe the factors and patterns influencing antibiotic use in LSBS among the membership of the North American Skull Base Society (NASBS).

Design An online-based survey was designed and distributed to the membership of the NASBS. Data was analyzed using bivariate analysis and logistic regression modeling.

Setting Online-based questionnaire.

Participants NASBS membership.

Main Outcome Measures Use of intraoperative antibiotics and use of postoperative antibiotics.

Results The survey response rate was 26% (208 respondents). Of the 208 total respondents, 143 (69%) respondents performed LSBS. Most respondents are neurosurgeons (69%) with the remaining being otolaryngologists (31%). The majority of respondents (79%) are fellowship-trained in skull base surgery. Academic or government physicians make up 69% of respondents and 31% are in private practice with or without academic affiliations. Bivariate analysis showed that practice setting significantly influenced intraoperative antibiotic use (p = 0.01). Geographic location significantly affected postoperative antibiotic use (p = 0.01). Postoperative antibiotic duration was significantly affected by presence of chronic otitis media, cerebrospinal fluid leak, and surgeon training (p = 0.02, p = 0.01, and p = 0.006, respectively). Logistic regression modeling showed that the motivation to reduce infection significantly impacted postoperative antibiotic use (p = 0.03).

Conclusion This study demonstrates significant variations in intraoperative and postoperative antibiotic use in LSBS among the NASBS membership. Appropriate guidelines for optimal perioperative antibiotic use patterns should be determined with randomized studies in the future.

Infections Due to Acinetobacter baumannii-calcoaceticus Complex: Escalation of Antimicrobial Resistance and Evolving Treatment Options

Bacteria within the genus Acinetobacter (principally A. baumannii-calcoaceticus complex [ABC]) are gram-negative coccobacilli that most often cause infections in nosocomial settings. Community-acquired infections are rare, but may occur in patients with comorbidities, advanced age, diabetes mellitus, chronic lung or renal disease, malignancy, or impaired immunity. Most common sites of infections include blood stream, skin/soft-tissue/surgical wounds, ventilator-associated pneumonia, orthopaedic or neurosurgical procedures, and urinary tract. Acinetobacter species are intrinsically resistant to multiple antimicrobials, and have a remarkable ability to acquire new resistance determinants via plasmids, transposons, integrons, and resistance islands. Since the 1990s, antimicrobial resistance (AMR) has escalated dramatically among ABC. Global spread of multidrug-resistant (MDR)-ABC strains reflects dissemination of a few clones between hospitals, geographic regions, and continents; excessive antibiotic use amplifies this spread. Many isolates are resistant to all antimicrobials except colistimethate sodium and tetracyclines (minocycline or tigecycline); some infections are untreatable with existing antimicrobial agents. AMR poses a serious threat to effectively treat or prevent ABC infections. Strategies to curtail environmental colonization with MDR-ABC require aggressive infection-control efforts and cohorting of infected patients. Thoughtful antibiotic strategies are essential to limit the spread of MDR-ABC. Optimal therapy will likely require combination antimicrobial therapy with existing antibiotics as well as development of novel antibiotic classes.

Effect of Cluster Nursing Based on Risk Management Strategy on Urinary Tract Infection in Patients With Severe Craniocerebral Injury

Objective

To observe the effect of cluster nursing based on risk management strategy in the management of urinary tract infection in patients with severe craniocerebral injury.

Methods

A total of 116 patients with severe craniocerebral injury who were admitted to our hospital from March 2019 to March 2021 were included. They were divided into the control group (58 patients) and the observation group (58 patients). The control group received routine nursing care and the observation group received cluster nursing based on risk management strategy. The incidence of catheter-associated urinary tract infection (CAUTI), the results of bacterial culture on the surface of the urinary catheter, the incidence of nursing risk events, the duration of placing the urinary catheter, the length of hospital stay, and hospital costs as well as the patient satisfaction score were compared between the two groups. The knowledge, attitude, and practice scale for prevention of catheter infection and the competence evaluation scale of nurses were used to evaluate the sense-control ability and core competence of the interveners.

Results

The total incidence of CAUTI in the observation group was (6.90%) lower than that in the control group (20.69%) (p < 0.05). The bacterial culture results on the catheter surface of patients in the observation group before and after 6 and 12 h of catheter cleaning were better than those of patients in the control group (p < 0.05). The duration of indwelling urinary catheter, hospitalization time, and hospitalization expenses of patients in the observation group were lower than those of patients in the control group (p < 0.05). The incidence rate of nursing risk events in the observation group was (1.72%) lower than that in the control group (11.86%) (p < 0.05). The overall satisfaction score of patients and the control and core ability scores of nursing staff in the observation group were higher than those in the control group (p < 0.05).

Conclusion

Cluster nursing based on risk management strategy can effectively reduce the incidence of nursing risk events and the probability of UTI in patients with severe craniocerebral injury, shorten the duration of indwelling urinary catheter and hospitalization.

Hospital-acquired infections caused by enterococci: a systematic review and meta-analysis, WHO European Region, 1 January 2010 to 4 February 2020

BackgroundHospital-acquired infections (HAI) caused by Enterococcus spp., especially vancomycin-resistant Enterococcusspp. (VRE), are of rising concern.AimWe summarised data on incidence, mortality and proportion of HAI caused by enterococci in the World Health Organization European Region.MethodsWe searched Medline and Embase for articles published between 1 January 2010 and 4 February 2020. Random-effects meta-analyses were performed to obtain pooled estimates.ResultsWe included 75 studies. Enterococcus spp. and VRE accounted for 10.9% (95% confidence interval (CI): 8.7-13.4; range: 6.1-17.5) and 1.1% (95% CI: 0.21-2.7; range: 0.39-2.0) of all pathogens isolated from patients with HAI. Hospital wide, the pooled incidence of HAI caused by Enterococcus spp. ranged between 0.7 and 24.8 cases per 1,000 patients (pooled estimate: 6.9; 95% CI: 0.76-19.0). In intensive care units (ICU), pooled incidence of HAI caused by Enterococcus spp. and VRE was 9.6 (95% CI: 6.3-13.5; range: 0.39-36.0) and 2.6 (95% CI: 0.53-5.8; range: 0-9.7). Hospital wide, the pooled vancomycin resistance proportion among Enterococcus spp. HAI isolates was 7.3% (95% CI: 1.5-16.3; range: 2.6-11.5). In ICU, this proportion was 11.5% (95% CI: 4.7-20.1; range: 0-40.0). Among patients with hospital-acquired bloodstream infections with Enterococcus spp., pooled all-cause mortality was 21.9% (95% CI: 15.7-28.9; range: 14.3-32.3); whereas all-cause mortality attributable to VRE was 33.5% (95% CI: 13.0-57.3; range: 14.3-41.3).ConclusionsInfections caused by Enterococcus spp. are frequently identified among hospital patients and associated with high mortality.

Risk factors and mortality associated with multidrug-resistant gram-negative bacterial infection in adult patients with abdominal surgery

BACKGROUND

Multidrug-resistant (MDR) gram-negative bacterial (GNB) infections remain a significant cause of morbidity and mortality among surgical patients. The objective of our study was to recognize the risk factors for MDR GNB infection in patients with abdominal surgery and determine the predictors independently associated with death.

METHODS

From 2010 to 2017, a retrospective cohort study was conducted among patients with abdominal surgery admitted in surgical intensive care unit (ICU). Patients with GNB infections were included for analyses.

RESULTS

A total of 364 patients with abdominal surgery experienced GNB infections, among them, 117 (32.1%) were MDR GNB infection. Of 133 MDR GNB isolates, the most frequent isolate was Escherichia coli (45.1%). Patients with MDR GNB infection had significantly longer ventilator days and hospital stay, as well as higher 30-day and in-hospital mortality compared to non-MDR GNB patients. Multivariable analysis showed longer length of pre-ICU stay, surgical re-exploration, receipt of group 2 carbapenems (e.g. imipenem, meropenem and doripenem) and fluoroquinolones, and higher total bilirubin were independent risk factors for the acquisition of MDR GNB infection. Predictors for 30-day mortality among patients with MDR GNB infection were chronic kidney disease, receipt of group 2 carbapenems and inappropriate empirical antimicrobial therapy.

CONCLUSIONS

This study provides important information about the risk factors for subsequent MDR GNB infection and 30-day mortality among the patients with abdominal surgery.

Insights into Acinetobacter baumannii: A Review of Microbiological, Virulence, and Resistance Traits in a Threatening Nosocomial Pathogen

Being a multidrug-resistant and an invasive pathogen, Acinetobacter baumannii is one of the major causes of nosocomial infections in the current healthcare system. It has been recognized as an agent of pneumonia, septicemia, meningitis, urinary tract and wound infections, and is associated with high mortality. Pathogenesis in A. baumannii infections is an outcome of multiple virulence factors, including porins, capsules, and cell wall lipopolysaccharide, enzymes, biofilm production, motility, and iron-acquisition systems, among others. Such virulence factors help the organism to resist stressful environmental conditions and enable development of severe infections. Parallel to increased prevalence of infections caused by A. baumannii, challenging and diverse resistance mechanisms in this pathogen are well recognized, with major classes of antibiotics becoming minimally effective. Through a wide array of antibiotic-hydrolyzing enzymes, efflux pump changes, impermeability, and antibiotic target mutations, A. baumannii models a unique ability to maintain a multidrug-resistant phenotype, further complicating treatment. Understanding mechanisms behind diseases, virulence, and resistance acquisition are central to infectious disease knowledge about A. baumannii. The aims of this review are to highlight infections and disease-producing factors in A. baumannii and to touch base on mechanisms of resistance to various antibiotic classes.

Methicillin-resistant Staphylococcus aureus (MRSA): antibiotic-resistance and the biofilm phenotype

Staphylococcus aureus (S. aureus) is an asymptomatic colonizer of 30% of all human beings. While generally benign, antibiotic resistance contributes to the success of S. aureus as a human pathogen. Resistance is rapidly evolved through a wide portfolio of mechanisms including horizontal gene transfer and chromosomal mutation. In addition to traditional resistance mechanisms, a special feature of S. aureus pathogenesis is its ability to survive on both biotic and abiotic surfaces in the biofilm state. Due to this characteristic, S. aureus is a leading cause of human infection. Methicillin-resistant S. aureus (MRSA) in particular has emerged as a widespread cause of both community- and hospital-acquired infections. Currently, MRSA is responsible for 10-fold more infections than all multi-drug resistant (MDR) Gram-negative pathogens combined. Recently, MRSA was classified by the World Health Organization (WHO) as one of twelve priority pathogens that threaten human health. In this targeted mini-review, we discuss MRSA biofilm production, the relationship of biofilm production to antibiotic resistance, and front-line techniques to defeat the biofilm-resistance system.

Impact of Antibiotic Therapy in the Microbiological Yield of Healthcare-Associated Ventriculitis and Meningitis

The impact of antibiotic therapy on the diagnosis of healthcare-associated ventriculitis and meningitis (HCAVM) is unknown. Antibiotics were administered before obtaining cerebrospinal fluid (CSF) in 217 out of 326 (66%) patients with HCAVM, and they impacted the sensitivity of the cerebrospinal fluid Gram stain and culture (P ≤ .004).

Therapeutic Effect of Linezolid in Children With Health Care-Associated Meningitis or Ventriculitis

We evaluated the efficacy of linezolid treatment in 6 children with health care-associated meningitis or ventriculitis (HCAMV) caused by gram-positive cocci. All children were diagnosed and treated at the Ehime University Hospital between January 2010 and December 2017. Of these, 5 were treated with linezolid as an empirical therapy. In these 5 patients, vancomycin was initially used but was changed to linezolid because of cerebrospinal fluid (CSF) culture positivity (n = 3) and a high minimum inhibitory concentration of vancomycin (n = 2). The most common HCAMV pathogens were methicillin-resistant coagulase-negative staphylococci (n = 3). In 3 patients, vancomycin concentration was low in CSF but reached the target concentration in serum, while linezolid concentration was high in both CSF and serum. HCAMV treatment using antimicrobial agents with poor CSF penetration may increase the likelihood of therapy failure. Linezolid is more susceptible as the first-line treatment for HCAMV compared with vancomycin.

Comparative efficacy of two different topical povidone-iodine 5% regimens in reducing conjunctival bacterial flora: A randomized parallel double-masked clinical trial

INTRODUCTION

The increasing prevalence of multi-resistant bacteria is a major public health concern. Infections acquired during ophthalmic surgery are devastating. The purpose of the current study is to compare the proportion of eyes with negative bacterial cultures on all tested media after 1 versus 3 sequential drops of povidone-iodine (PI) 5% into the inferior conjunctival fornix.

METHODS

Patients were randomly assigned to receive 1 (PI group) drop (at time 28 minutes) or 3 (PI plus group) sequential drops (at time 0, 20 minutes and 28 minutes) of PI 5% into the inferior conjunctival sac of one randomly selected eye. A swab culture was obtained from the inferior conjunctival fornix 5 minutes before and 30 minutes after time 0. Central corneal thickness (CCT) was measured shortly before time 0 and shortly after time 30. Conjunctival swabs were incubated aerobically in enriched Thioglycolate liquid medium (meat broth) and in three solid culture media (chocolate agar, trypticase soy agar with 5% sheep blood, and Sabouraud agar).

RESULTS

There was no significant difference in the proportion of negative cultures after intervention between groups (p = 0.1638). Also in the PI group (n = 59), the proportion of eyes with negative cultures after PI (79.7%) did not differ significantly from baseline (76.3%; p = 0.7539). However in the PI plus group (n = 61), the proportion of eyes with all negative cultures after PI (85.3%) was significantly higher than before PI (70.5%) (p = 0.0177). There was no significant difference in mean CCT before and after the intervention in both groups.

CONCLUSION

Instillation of 3 sequential drops of PI was associated with a significant increase in the proportion of eyes with all negative cultures, while instillation of a single drop of PI was not associated with a significant increase in the proportion of negative cultures. Further study is warranted to determine whether the difference between the PI administration regimens is also associated with differences in the rates of postoperative ocular infections.

Molecular epidemiology of carbapenem-resistant Acinetobacter baumannii in Greece: an extended review (2000–2015)

Carbapenem-resistant Acinetobacter baumannii (CRAB) is endemic in Greece. CRAB initially emerged in 2000 and since then, carbapenemases still have a crucial role in CRAB appearance, except for a few cases resulting from efflux pump or outer-membrane protein mechanisms. OXA-type carbapenemases present the highest prevalence worldwide and bla OXA-23-like and bla OXA-58-like are the most important genes found; VIM-yielding CRAB have also been detected, while a single CRAB isolate producing NDM has quite recently emerged in Greece. The predominant OXA-23 producers are associated with multilocus sequence typing Pasteur scheme sequence type 2 clonal strains of the international clone II. The emergence of colistin-resistant CRAB has complicated the treatment of such infections and the interpretation of susceptibility data. Infection control measures and adjusted antimicrobial treatment strategies could confine CRAB spread. The aim of this review is to go through the molecular epidemiology of CRAB, in an endemic area and highlight its potential future evolution.