Impact of a multimodal strategy combining a new standard of care and restriction of carbapenems, fluoroquinolones and cephalosporins on antibiotic consumption and resistance of Pseudomonas aeruginosa in a French intensive care unit

Characteristics of Pseudomonas aeruginosa infection in intensive care unit before (2007-2010) and after (2011-2014) the beginning of an antimicrobial stewardship program

Objectives

To investigate the factors associated with Pseudomonas aeruginosa isolates in intensive care unit (ICU) before and after an antimicrobial stewardship program.

Materials

Monocentric retrospective cohort study. Patients admitted to the ICU in 2007-2014 were included. Characteristics of P. aeruginosa patients were compared to overall ICU population. Clinical and microbiological characteristics of P. aeruginosa patients before (2007-2010) and after (2011-2014) the beginning of the AMP were compared.

Results

Overall, 5,263 patients were admitted to the ICU, 274/5,263 (5%) had a P. aeruginosa isolate during their staying. In 2011-2014, the percentage P. aeruginosa isolates reduced (7% vs 4%, P ≤ .0001). Patients with P. aeruginosa had higher rates of in-hospital death (43% vs 20%, P < .0001) than overall ICU population. In 2011-2014, rates of multidrug-resistant (11% vs 2%, P = .0020), fluoroquinolone-resistant (35% vs 12%, P < .0001), and ceftazidime-resistant (23% vs 8%, P = .0009) P. aeruginosa reduced. Treatments by fluoroquinolones (36% vs 4%, P ≤ .0001), carbapenems (27% vs 9%, P = .0002), and third-generation cephalosporins (49% vs 12%, P ≤ .0001) before P. aeruginosa isolation reduced while piperacillin (0% vs 13%, P < .0001) and trimethoprim-sulfamethoxazole (8% vs 26%, P = .0023) increased. Endotracheal intubation reduced in 2011-2014 (61% vs 35%, P < .0001). Fluoroquinolone-resistance was higher in patients who received endotracheal intubation (29% vs 17%, P = .0197). Previous treatment by fluoroquinolones (OR = 2.94, P = .0020) and study period (2007-2010) (OR = 2.07, P = .0462) were the factors associated with fluoroquinolone-resistance at the multivariate analysis.

Conclusions

Antibiotic susceptibility in P. aeruginosa isolates was restored after the reduction of endotracheal intubation, fluoroquinolones, carbapenems, and third-generation cephalosporins and the increased use of molecules with a low ecological footprint, as piperacillin and trimethoprim-sulfamethoxazole.

Difference between days of therapy and days of antibiotic spectrum coverage in an inpatient antimicrobial stewardship program: Vector autoregressive models for time-series analysis

OBJECTIVE

The days of therapy (DOT) metric, used to estimate antimicrobial consumption, has some limitations. Days of antibiotic spectrum coverage (DASC), a novel metric, overcomes these limitations. We examined the difference between these 2 metrics of inpatient intravenous antimicrobial consumption in assessing antimicrobial stewardship efficacy and antimicrobial resistance using vector autoregressive (VAR) models with time-series analysis.

METHODS

Differences between DOT and DASC were investigated at a tertiary-care center over 8 years using VAR models with 3 variables in the following order: (1) the monthly proportion of prospective audit and feedback (PAF) acceptance as an index of antimicrobial stewardship efficacy; (2) monthly DOT and DASC adjusted by 1,000 days present as indices of antimicrobial consumption; and (3) the monthly incidence of 5 organisms as an index of antimicrobial resistance.

RESULTS

The Granger causality test, which evaluates whether incorporating lagged variables can help predict other variables, showed that PAF activity contributed to DOT and DASC, which, in turn, contributed to the incidence of drug-resistant P. aeruginosa. Notably, only DASC helped predict the incidence of drug-resistant Enterobacterales. Another VAR analysis demonstrated that a high proportion of PAF acceptance was accompanied by decreased DASC in a given month, whereas increased DASC was accompanied by an increased incidence of drug-resistant Enterobacterales, unlike with DOT.

CONCLUSIONS

The VAR models of PAF activity, antimicrobial consumption, and antimicrobial resistance suggested that DASC may more accurately reflect the impact of PAF on antimicrobial consumption and be superior to DOT for predicting the incidence of drug-resistant Enterobacterales.

Evaluation of prescription review and feedback policy on rational antibiotic use in primary healthcare settings in Beijing, China: a qualitative study using the Theoretical Domains Framework and the behaviour change wheel

Objectives

To decelerate antibiotic resistance driven by inappropriate antibiotic prescribing, a prescription review and feedback (PRF) policy is implemented in primary healthcare institutions (PHIs) in Beijing, China. However, evaluation of PRF implementation in PHIs is scarce. This study aims to systematically identify the barriers and facilitators of PRF policy implementation to provide evidence for antimicrobial stewardship.

Methods

We conducted key informant interviews with 40 stakeholders engaged in the implementation of PRF in Beijing, including physicians, pharmacists and administrators. Interviews were audio recorded and transcribed verbatim. We coded the interview transcripts and mapped informant views to domains of the Theoretical Domains Framework. We then used a behaviour change wheel to suggest possible behavioural interventions.

Results

Procedural knowledge (Knowledge) and skills (Skill) of PRF were possessed by stakeholders. They felt responsible to promote the appropriate use of antibiotics (Social/professional role and identity) and believed that PRF could help to change inappropriate provider behaviours (Behavioural regulation) in prescribing antibiotics (Beliefs about consequences) under increased intention on antibiotic use (Stages of change). Moreover, informants called for a more unified review standard to enhance PRF implementation (Goals). Frequently identified barriers to PRF included inadequate capacity (Skill), using punishment mechanism (Behaviour regulation), reaching consistently lower antibiotic prescription rates (Goals), lack of resources (Environmental context and resources) and perceived pressure coming from patients (Social influences).

Conclusions

Stakeholders believed that PRF implementation promoted the rational use of antibiotics at PHIs in Beijing. Still, PRF was hampered by inconsistencies in review process and resources needed for PRF implementation.

Genomics of Aminoglycoside Resistance in Pseudomonas aeruginosa Bloodstream Infections at a United States Academic Hospital

Pseudomonas aeruginosa frequently becomes resistant to aminoglycosides by the acquisition of aminoglycoside modifying enzyme (AME) genes and the occurrence of mutations in the mexZ, fusA1, parRS, and armZ genes. We examined resistance to aminoglycosides in a collection of 227 P. aeruginosa bloodstream isolates collected over 2 decades from a single United States academic medical institution. Resistance rates of tobramycin and amikacin were relatively stable over this time, while the resistance rates of gentamicin were somewhat more variable. For comparison, we examined resistance rates to piperacillin-tazobactam, cefepime, meropenem, ciprofloxacin, and colistin. Resistance rates to the first four antibiotics were also stable, although uniformly higher for ciprofloxacin. Colistin resistance rates were initially quite low, rose substantially, and then began to decrease at the end of the study. Clinically relevant AME genes were identified in 14% of isolates, and mutations predicted to cause resistance were relatively common in the mexZ and armZ genes. In a regression analysis, resistance to gentamicin was associated with the presence of at least one gentamicin-active AME gene and significant mutations in mexZ, parS, and fusA1. Resistance to tobramycin was associated with the presence of at least one tobramycin-active AME gene. An extensively drug-resistant strain, PS1871, was examined further and found to contain five AME genes, most of which were within clusters of antibiotic resistance genes embedded in transposable elements. These findings demonstrate the relative contributions of aminoglycoside resistance determinants to P. aeruginosa susceptibilities at a United States medical center. IMPORTANCE Pseudomonas aeruginosa is frequently resistant to multiple antibiotics, including aminoglycosides. The rates of resistance to aminoglycosides in bloodstream isolates collected over 2 decades at a United States hospital remained constant, suggesting that antibiotic stewardship programs may be effective in countering an increase in resistance. Mutations in the mexZ, fusA1, parR, pasS, and armZ genes were more common than acquisition of genes encoding aminoglycoside modifying enzymes. The whole-genome sequence of an extensively drug resistant isolate indicates that resistance mechanisms can accumulate in a single strain. Together, these results suggest that aminoglycoside resistance in P. aeruginosa remains problematic and confirm known resistance mechanisms that can be targeted for the development of novel therapeutics.

Quorum sensing inhibitors as Therapeutics: Bacterial biofilm inhibition

The overuse and inappropriate use of antibiotics to treat bacterial infections has led to the development of multiple drug resistant strains. Biofilm is a complex microorganism aggregation defined by the presence of a dynamic, sticky, and protective extracellular matrix made of polysaccharides, proteins, and nucleic acids. The infectious diseases are caused by bacteria that flourish within quorum sensing (QS) mediated biofilms. Efforts to disrupt biofilms have enabled the identification of bioactive molecules produced by prokaryotes and eukaryotes. The QS system is quenched predominantly by these molecules. The phenomenon is also termed as quorum sensing (QS). Both synthetic and natural substances have been discovered to be useful in QS. This review describes natural and synthetic quorum sensing inhibitors (QSIs) with the potential to treat bacterial infections. It includes the discussion on quorum sensing, mechanism of quorum sensing, effect of substituents on the activity. These discoveries could result in effective therapies using far lower dosages of medications, particularly antibiotics, are currently needed.

The Production of Antibiotics Must Be Reoriented: Repositioning Old Narrow-Spectrum Antibiotics, Developing New Microbiome-Sparing Antibiotics

The development of broad-spectrum antibiotics to control multidrug-resistant bacteria is an outdated business model. This strategy has led to the introduction of highly effective antibiotics, but their widespread use has contributed to the emergence of even broader antibiotic resistance. In a strategy to combat antimicrobial resistance, we believe that the use of narrow-spectrum antibiotics should be promoted. This should involve both the repositioning of old antibiotics and the reorientation of research and development towards new narrow-spectrum antibiotics with a low ecological impact. These antibiotics could be prescribed for common conditions such as sore throats and cystitis, which account for the bulk of antibiotic use in humans. Narrow-spectrum, targeted, microbiome-sparing antibiotics could help control antibiotic resistance while being economically sustainable. Their development and production should be supported by governments, which would ultimately benefit from reduced health care costs.

The problem of multi-resistance in gram-negative bacilli in intensive care units: Treatment and prevention strategies

The rise of infections caused by multi-resistant gram-negative bacilli (MR-GNB), which includes carbapenems, represents one of the major current challenges worldwide. These MR-GNB include extended spectrum β-lactamase-producing Enterobacterales, derepressed AmpC-producing or carbapenemase-producing Enterobacterales as well as non-fermenting Gram-negative bacilli such as Pseudomonas aeruginosa or Acinetobacter baumannii. P. aeruginosa predominantly exhibits other resistance mechanisms different to β-lactamases such as expulsion pumps or loss of porins. A. baumannii frequently presents several of these resistance mechanisms. Mortality is high especially if empirical treatment is inadequate. In this review, treatment strategies are revised, describing the tools available to identify patients in whom empirical antibiotic treatment would be justified to cover MR-GNB, the importance of optimizing the administration of these antibiotics, as well as prevention strategies to avoid its spread from patients colonized or infected by a MR-GNB.

Pseudomonas aeruginosa Pneumonia: Evolution of Antimicrobial Resistance and Implications for Therapy

Pseudomonas aeruginosa (PA), a non-lactose-fermenting gram-negative bacillus, is a common cause of nosocomial infections in critically ill or debilitated patients, particularly ventilator-associated pneumonia (VAP), and infections of urinary tract, intra-abdominal, wounds, skin/soft tissue, and bloodstream. PA rarely affects healthy individuals, but may cause serious infections in patients with chronic structural lung disease, comorbidities, advanced age, impaired immune defenses, or with medical devices (e.g., urinary or intravascular catheters, foreign bodies). Treatment of pseudomonal infections is difficult, as PA is intrinsically resistant to multiple antimicrobials, and may acquire new resistance determinants even while on antimicrobial therapy. Mortality associated with pseudomonal VAP or bacteremias is high (> 35%) and optimal therapy is controversial. Over the past three decades, antimicrobial resistance (AMR) among PA has escalated globally, via dissemination of several international multidrug resistant "epidemic" clones. We discuss the importance of PA as a cause of pneumonia including health care-associated pneumonia, hospital-acquired pneumonia, VAP, the emergence of AMR to this pathogen, and approaches to therapy (both empirical and definitive).

Risk of Multidrug Resistant Bacteria Acquisition in Patients with Declared β-Lactam Allergy during Hospitalization in Intensive Care Unit: A Retrospective Cohort Study (2007-2018)

Introduction

The risk of extended spectrum β-lactamase (ESBL) bacterial acquisition in patients with β-lactam allergy has been poorly investigated. In a previous study conducted over a 6-year long period (2007-2012), we found that patients with declared β-lactam allergy had a higher risk of ESBL bacterial carriage at admission in intensive care unit (ICU), but they had not a higher risk of ESBL bacterial acquisition. We present the final results of the study which was eventually conducted over a 12-year long period (2007-2018).

Materials and Methods

The study included all patients admitted in ICU and receiving antibiotic treatment from January 2007 to December 2018. ESBL bacterial acquisition was the main clinical outcome. Mortality in ICU, multidrug resistant bacterial carriage at admission and discharge were the secondary outcomes.

Results

Overall, 3332 patients were included, 132/3332 (3.9%) were labelled β-lactam allergic, while 3200/3332 (96.1%) did not presented β-lactam allergy. No significant difference in rates of ESBL acquisition was detected (4/132, 3% vs. 78/3200, 2.4%; p = 0.17). Patients with β-lactam allergy had higher rates of ESBL bacterial carriage at admission (19/132, 14.4% vs. 248/3200, 7.8%, p = 0.01) and at discharge (22/132, 16.7% vs. 351/3200, 11%, p = 0.04) than nonallergic patients. No differences in mortality, duration of hospitalization, and carriage of methicillin resistant Staphylococcus aureus were reported. Female gender was the only factor associated with β-lactam allergy at the multivariate analysis.

Conclusions

This study confirms that patients with declared β-lactam allergy had not a higher risk of ESBL bacterial acquisition during hospitalization in ICU. However, they had a higher ESBL bacterial carriage at admission.

Antimicrobial Resistance Among Pathogens Causing Bloodstream Infections: A Multicenter Surveillance Report Over 20 Years (1998–2017)

Purpose

Bloodstream infections (BSIs) are a common consequence of infectious diseases and cause high morbidity and mortality. Appropriate antibiotic use is critical for patients’ treatment and prognosis. Long-term monitoring and analysis of antimicrobial resistance are important in guiding physicians to choose appropriate antibiotics and understand the changes in antimicrobial resistance and infection control. Here, we report a retrospective study on the trends of antimicrobial resistance in the common BSI-associated pathogens.

Methods

The identification of strains and antimicrobial susceptibility tests were performed in each anticipating hospital independently. Data from the Hubei Province Antimicrobial Resistance Surveillance System (HBARSS) from 1998 to 2017 were retrospectively analyzed using WHONET 5.6 software.

Results

Data from HBARSS (1998–2017) revealed that 40,518 Gram-positive bacteria and 26,568 Gram-negative bacteria caused BSIs, the most common of which were Staphylococcus aureus and Escherichia coli. Salmonella typhi was a predominant BSI-associated pathogen in 1998–2003. Antimicrobial susceptibility data showed that the resistance rates of E. coli and Klebsiella pneumoniae to cefotaxime were significantly higher than those to ceftazidime. The proportion of strains of special antimicrobial resistance phenotypes including difficult-to-treat resistance (DTR), carbapenem-resistant (CR), extended-spectrum cephalosporin resistant (ECR) and fluoroquinolone resistant (FQR) in E. coli was 0.18%, 0.26%, 13.95%, 22.78% while in K. pneumoniae was 11.95%, 14.00%, 31.91% and 11.40%, respectively. In 2013–2017, K. pneumoniae showed resistance levels reaching 15.8% and 17.5% to imipenem and meropenem, respectively, and Acinetobacter baumannii showed high resistance rates ranging from 60 to 80% to common antibiotics. The detection rate of Salmonella typhi resistance to third-generation cephalosporins and fluoroquinolones was less than 5%. Control of methicillin-resistant Staphylococcus aureus (MRSA) remains a major challenge, and in 2009–2017, the MRSA detection rate was 40–50%.

Conclusion

Prevalence of CR K. pneumoniae has increased significantly in recent years. Resistance rates of A. baumannii to common antimicrobial agents have increased exponentially, reaching high levels. MRSA remains a challenge to control. For K. pneumoniae, DTR, CR, ECR and FQR were antimicrobial resistance phenotypes that could not be ignored while for E. coli DTR and CR were rare antimicrobial resistance phenotypes. CR K. pneumoniae, A. baumannii and MRSA present major challenges for controlling BSIs.

Antimicrobial resistance and antibiotic consumption in intensive care units, Switzerland, 2009 to 2018

Background

Intensive care units (ICU) constitute a high-risk setting for antimicrobial resistance (AMR).

Aim

We aimed to describe secular AMR trends including meticillin-resistant Staphylococcus aureus (MRSA), glycopeptide-resistant enterococci (GRE), extended-spectrum cephalosporin-resistant Escherichia coli (ESCR-EC) and Klebsiella pneumoniae (ESCR-KP), carbapenem-resistant Enterobacterales (CRE) and Pseudomonas aeruginosa (CRPA) from Swiss ICU. We assessed time trends of antibiotic consumption and identified factors associated with CRE and CRPA.

Methods

We analysed patient isolate and antibiotic consumption data of Swiss ICU sent to the Swiss Centre for Antibiotic Resistance (2009–2018). Time trends were assessed using linear logistic regression; a mixed-effects logistic regression was used to identify factors associated with CRE and CRPA.

Results

Among 52 ICU, MRSA decreased from 14% to 6% (p = 0.005; n = 6,465); GRE increased from 1% to 3% (p = 0.011; n = 4,776). ESCR-EC and ESCR-KP increased from 7% to 15% (p < 0.001, n = 10,648) and 5% to 11% (p = 0.002; n = 4,052), respectively. CRE, mostly Enterobacter spp., increased from 1% to 5% (p = 0.008; n = 17,987); CRPA remained stable at 27% (p = 0.759; n = 4,185). Antibiotic consumption in 58 ICU increased from 2009 to 2013 (82.5 to 97.4 defined daily doses (DDD)/100 bed-days) and declined until 2018 (78.3 DDD/100 bed-days). Total institutional antibiotic consumption was associated with detection of CRE in multivariable analysis (odds ratio per DDD: 1.01; 95% confidence interval: 1.0–1.02; p = 0.004).

Discussion

In Swiss ICU, antibiotic-resistant Enterobacterales have been steadily increasing over the last decade. The emergence of CRE, associated with institutional antibiotic consumption, is of particular concern and calls for reinforced surveillance and antibiotic stewardship in this setting.

Ventilator-Associated Pneumonia in COVID-19 Patients: A Retrospective Cohort Study

INTRODUCTION

Aim of this study is to analyse the characteristics of ventilator-associated pneumonia (VAP) inpatients infected by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2).

MATERIALS AND METHODS

A retrospective study was conducted, including coronavirus infectious disease 2019 (COVID-19) patients who developed VAP from March to May 2020 (VAP COVID-19). They were compared to non-COVID-19 patients who developed VAP from January 2011 to December 2019 (VAP NO COVID-19) and COVID-19 patients who did not develop VAP (NO VAP COVID-19).

RESULTS

Overall, 42 patients were included in the VAP COVID-19group, 37 in the NO VAP COVID-19 group, and 188 in the VAP NO COVID-19 group. VAP COVID-19 had significantly higher rates of shock (71% vs. 48%, p = 0.009), death in ICU (52% vs. 30%, p = 0.011), VAP recurrence (28% vs. 4%, p < 0.0001), positive blood culture (26% vs. 13%, p = 0.038), and polymicrobial culture (28% vs. 13%, p = 0.011) than VAP NO COVID-19. At the multivariate analysis, death in patients with VAP was associated with shock (p = 0.032) and SARS-CoV-2 (p = 0.008) infection.

CONCLUSIONS

VAP in COVID-19 patients is associated with shock, bloodstream, and polymicrobial infections.

A comprehensive assessment of carbapenem use across 90 Veterans Health Administration hospitals with defined stewardship strategies for carbapenems

OBJECTIVES

Carbapenems are an important target for antimicrobial stewardship (AS) efforts. In this study, we sought to compare different hospital-based strategies for improving carbapenem use.

METHODS

We analysed a cohort of all patients hospitalized at Veterans Health Administration (VHA) acute care hospitals during 2016 and a mandatory survey that characterized each hospital's carbapenem-specific AS strategy into one of three types: no strategy (NS), prospective audit and feedback (PAF) or restrictive policies (RP). Carbapenem use was compared using risk-adjusted generalized estimating equations that accounted for clustering within hospitals. Two infectious disease (ID) physicians independently performed manual chart reviews in 425 randomly selected cases. Auditors assessed carbapenem appropriateness with an assessment score on Day 4 of therapy.

RESULTS

There were 429 062 admissions in 90 sites (24 NS, 8 PAF, 58 RP). Carbapenem use was lower at PAF than NS sites [rate ratio (RR) 0.6 (95% CI 0.4-0.9); P = 0.01] but similar between RP and NS sites. Carbapenem prescribing was considered appropriate/acceptable in 215 (50.6%) of the reviewed cases. Assessment scores were lower (i.e. better) at RP than NS sites (mean 2.3 versus 2.7; P < 0.01) but did not differ significantly between NS and PAF sites. ID consultations were more common at PAF/RP than NS sites (51% versus 29%; P < 0.01). ID consultations were associated with lower (i.e. better) assessment scores (mean 2.3 versus 2.6; P < 0.01).

CONCLUSIONS

In this VHA cohort, PAF strategies were associated with lower carbapenem use and ID consultation and RP strategies were associated with more appropriate carbapenem prescribing. AS and ID consultations may work complementarily and hospitals could leverage both to optimize carbapenem use.

Pseudomonas aeruginosa: a clinical and genomics update

Antimicrobial resistance (AMR) has become a global medical priority that needs urgent resolution. Pseudomonas aeruginosa is a versatile, adaptable bacterial species with widespread environmental occurrence, strong medical relevance, a diverse set of virulence genes and a multitude of intrinsic and possibly acquired antibiotic resistance traits. P. aeruginosa causes a wide variety of infections and has an epidemic-clonal population structure. Several of its dominant global clones have collected a wide variety of resistance genes rendering them multi-drug resistant (MDR) and particularly threatening groups of vulnerable individuals including surgical patients, immunocompromised patients, Caucasians suffering from cystic fibrosis (CF) and more. AMR and MDR especially are particularly problematic in P. aeruginosa significantly complicating successful antibiotic treatment. In addition, antimicrobial susceptibility testing (AST) of P. aeruginosa can be cumbersome due to its slow growth or the massive production of exopolysaccharides and other extracellular compounds. For that reason, phenotypic AST is progressively challenged by genotypic methods using whole genome sequences (WGS) and large-scale phenotype databases as a framework of reference. We here summarize the state of affairs and the quality level of WGS-based AST for P. aeruginosa mostly from clinical origin.

Does Fluoroquinolones and Third-Generation Cephalosporins Restriction Reverse Extended-Spectrum β-Lactamases Klebsiella pneumoniae Resistance Rates?

Aim: To decrease the incidence and resistance rates of extended-spectrum β-lactamases (ESBL) Klebsiella pneumoniae (KP) by restriction of the use of third-generation cephalosporins (3GCs) and fluoroquinolones. Methods: Consumption of 3GCs, fluoroquinolones, and carbapenems in association with ertapenem and fluoroquinolone-resistant KP isolates, were analyzed in 21 months by autoregressive integrated moving average models. A follow-up analysis was performed 5 years later. Results: Consumption of 3GCs decreased significantly during the postintervention period. Their restriction was associated with a decrease in ertapenem-resistant KP isolates by 17.5%. Fluoroquinolone, 3GCs, and carbapenem use did not significantly predict the percentage of ertapenem-resistant KP isolates. Fluoroquinolone, but not cephalosporin use, significantly predicted the percentage of fluoroquinolone-resistant isolates, with an increase of 1 defined daily dose (DDD) of fluoroquinolone/100 occupied bed-days (OBDs) corresponding to a 0.32% increase of fluoroquinolone-resistant isolates (p = 0.008). A decrease of 1 DDD of carbapenem/100 OBD was associated with a 16.94% increase of fluoroquinolone-resistant isolates (p = 0.007). Five years later, the consumption of all three antimicrobial classes increased significantly compared with the 2011-2013 period, whereas ertapenem-resistant KP rates significantly decreased. Conclusion: This study may bring a valuable contribution to the understanding of the intricate association between antibiotic consumption and bacterial resistance. Reporting a spectrum of different results could present a useful basis for more profound research of various interventions' effects.

Trimethoprim-sulfamethoxazole as de-escalation in ventilator-associated pneumonia: a cohort study subanalysis

Purpose

This is a subanalysis of a previous study which compared the effectiveness of trimetoprim-sulfametoxazole (TMP-SMX) with all other regimens for treatment of ventilator-associated pneumonia (VAP). Aim of the current study was to focus on the effectiveness of a strategy based on TMP-SMX as de-escalation from β-lactam including regimens.

Methods

Retrospective cohort study including patients who were hospitalized for VAP from 2011 to 2019. Patients were distributed in two groups: NO SWITCH TO TMP-SMX group, including patients who received β-lactams for all treatment duration, and SWITCH TO TMP-SMX group, which included patients who switched to TMP-SMX from a β-lactam including regimen after microbiology diagnosis. Three clinical outcomes were analyzed: mortality at 30 days from the start of the antibiotic treatment (T30), mortality at the end of treatment (EoT), and acquisition of multidrug-resistant bacteria during hospitalization in intensive care unit.

Results

Overall, 70 patients were included in the current study, 32/70 (45.7%) in NO SWITCH TO TMP-SMX group and 38/70 (54.3%) in SWITCH TO TMP-SMX group, 37/70 (52.8%) had been already included in the previous study. No significant differences in clinical outcomes and patient’s characteristics were found when the two groups were compared.

Conclusions

De-escalation to TMP-SMX for VAP treatment was not associated with higher mortality at EoT and T30 than standard treatment with β-lactam. Monotherapy with TMP-SMX as de-escalation from broad-spectrum empirical regimens is a β-lactam sparing strategy worthy to be further investigated in either multicenter cohort studies or randomized clinical trials.

Antibiotic Resistance, Biofilm Formation, and Presence of Genes Encoding Virulence Factors in Strains Isolated from the Pharmaceutical Production Environment

The spread of bacterial resistance to antibiotics affects various areas of life. The aim of this study was to assess the occurrence of Pseudomonas aeruginosa, and other bacteria mainly from orders Enterobacterales and Staphylococcus in the pharmaceutical production sites, and to characterize isolated strains in the aspects of antibiotic resistance, biofilm formation, and presence of genes encoding virulence factors. Genes encoding selected virulence factors were detected using PCR techniques. Antimicrobial susceptibility testing was applied in accordance with the EUCAST recommendations. A total of 46 P. aeruginosa strains were isolated and 85% strains showed a strong biofilm-forming ability. The qualitative identification of genes taking part in Quorum Sensing system demonstrated that over 89% of strains contained lasR and rhlI genes. An antimicrobial susceptibility testing revealed nine strains resistant to at least one antibiotic, and two isolates were the metallo-β-lactamase producers. Moreover, the majority of P. aeruginosa strains contained genes encoding various virulence factors. Presence of even low level of pathogenic microorganisms or higher level of opportunistic pathogens and their toxic metabolites might result in the production inefficiency. Therefore, the prevention of microbial contamination, effectiveness of sanitary and hygienic applied protocols, and constant microbiological monitoring of the environment are of great importance.

Effectiveness and Acceptance of Multimodal Antibiotic Stewardship Program: Considering Progressive Implementation and Complementary Strategies

Multiple modes of interventions are available when implementing an antibiotic stewardship program (ASP), however, their complementarity has not yet been assessed. In a 938-bed hospital, we sequentially implemented four combined modes of interventions over one year, centralized by one infectious diseases specialist (IDS): (1) on-request infectious diseases specialist consulting service (IDSCS), (2) participation in intensive care unit meetings, (3) IDS intervention triggered by microbiological laboratory meetings, and (4) IDS intervention triggered by pharmacist alert. We assessed the complementarity of the different cumulative actions through quantitative and qualitative analysis of all interventions traced in the electronic medical record. We observed a quantitative and qualitative complementarity between interventions directly correlating to a decrease in antibiotic use. Quantitatively, the number of interventions has doubled after implementation of IDS intervention triggered by pharmacist alert. Qualitatively, these kinds of interventions led mainly to de-escalation or stopping of antibiotic therapy (63%) as opposed to on-request IDSCS (32%). An overall decrease of 14.6% in antibiotic use was observed (p = 0.03). Progressive implementation of the different interventions showed a concrete complementarity of these actions. Combined actions in ASPs could lead to a significant decrease in antibiotic use, especially regarding critical antibiotic prescriptions, while being well accepted by prescribers.

The Role of Antibiotic Stewardship and Telemedicine in the Management of Multidrug-Resistant Infections

This article summarizes the literature describing how antimicrobial stewardship and telemedicine interventions affect antimicrobial resistance. Discussion includes why we need stewardship, how to collaborate with team members, and the evidence of stewardship's and telemedicine's impact on resistance.

Impact of systematic screening for AmpC-hyperproducing Enterobacterales intestinal carriage in intensive care unit patients

BACKGROUND

Empirical antimicrobial therapy (EAT) is a challenge for community-acquired, hospital-acquired and ventilator-associated pneumonia, particularly in the context of the increasing occurrence of third-generation cephalosporin-resistant Enterobacterales (3GCR-E), including extended-spectrum beta-lactamase Enterobacterales (ESBL-E) and high-level expressed AmpC cephalosporinase-producing Enterobacterales (HLAC-E). To prevent the overuse of broad-spectrum antimicrobial therapies, such as carbapenems, we assessed the performance of screening for intestinal carriage of HLAC-E in addition to ESBL-E to predict 3GCR-E (ESBL-E and/or HLAC-E) presence or absence in respiratory samples in ICU, and to evaluate its potential impact on carbapenem prescription.

MATERIALS AND METHODS

This monocentric retrospective observational study was performed in a surgical ICU during a 4-year period (January 2013-December 2016). Patients were included if they had a positive culture on a respiratory sample and a previous intestinal carriage screening performed by rectal swabbing within 21 days. Sensitivity, specificity, positive (PPV) and negative (NPV) predictive values and likelihood ratios were calculated for the screening for intestinal carriage of ESBL-E, HLAC-E and 3GCR-E (ESBL-E and/or HLAC-E) as predictor of their absence/presence in respiratory samples. Impact of HLAC-E and ESBL-E reporting on EAT was also studied.

RESULTS

765 respiratory samples, retrieved from 468 patients, were analyzed. ESBL-E prevalence was 23.8% in rectal swab and 4.4% in respiratory samples. HLAC-E prevalence was 9.0% in rectal swabs and 3.7% in respiratory samples. Overall, the 3GCR-E prevalence was 31.8% in rectal swabs and 7.7% in respiratory samples. NPVs were 98.8%, 98.0% and 96.6% for ESBL-E, HLAC-E and 3GCR-E, respectively. Over the study period, empirical antimicrobial therapy was initiated for 315 episodes of respiratory infections: 228/315 (72.4%) were associated with negative intestinal carriage screening for both HLAC-E and ESBL-E, of whom 28/228 (12.3%) were treated with carbapenems. Of 23/315 (7.3%) cases with screening for positive intestinal carriage with HLAC-E alone, 10/23 (43.5%) were treated with carbapenems.

CONCLUSION

Systematic screening and reporting of HLAC-E in addition to ESBL-E in intestinal carriage screening could help to predict the absence of 3GCR-E in respiratory samples of severe surgical ICU patients. This could improve the appropriateness of EAT in ICU patients with HAP and may prevent the overuse of carbapenems.

Pseudomonas aeruginosa infection in intensive care: Epidemiology, outcomes, and antimicrobial susceptibilities

BACKGROUND

Pseudomonas aeruginosa (PA) infection in the intensive care unit (ICU) contributes to substantial mortality. In this study, we describe the epidemiology, antimicrobial susceptibilities, and outcomes of ICU patients with pseudomonal infection.

METHODS

ICU patients with PA were identified and classified as colonized or infected. Infected patients were reviewed for source, patient characteristics, antimicrobial susceptibilities, appropriateness of empiric antimicrobial therapy, and 30-day mortality. Independent predictors of mortality were identified using multivariable logistic regression.

RESULTS

One hundred forty (71%) patients with PA were infected. Mean patient age was 55 (SD 18) years; 62% were male. Admission categories included medical (71%), surgical (20%), and trauma or neurological (9%). Mean Acute Physiology and Chronic Health Evaluation (APACHE) II score was 19 (SD 10). One hundred twenty-six (90%) patients were mechanically ventilated, 102 (73%) required vasopressors, and 27 (19%) received renal replacement; 32 (23%) died within 30 days. Infection was nosocomial in 101 (72%) cases. Sources were respiratory (66%), skin-soft tissue (11%), urinary (10%), blood (5%), surgical (5%), gastrointestinal (2%), or unknown (1%). Twenty (14%) isolates were multi-drug resistant; 6 (4%) were extensively drug resistant. Empiric antimicrobial therapy was effective in 97 (69%) cases. Liver disease (adjusted OR [aOR] 6.2, 95% CI 1.5 to 25.7; p = 0.01), malignancy (aOR 5.0, 95% CI 1.5 to 17.3; p = 0.01), and higher APACHE II score (aOR 1.1, 95% CI 1.0 to 1.1; p = 0.02) were independently associated with 30-day mortality.

CONCLUSIONS

PA infection in ICU is most commonly respiratory and associated with substantial mortality. Existing malignancy, liver disease, and higher APACHE II score were independently associated with mortality.

Epidemiology and risk factors for healthcare-associated infections caused by Pseudomonas aeruginosa

Pseudomonas aeruginosa (PA) is a globally recognized cause of healthcare-associated infections (HAIs). The aim of our cross-sectional study, conducted in a Serbian tertiary care hospital, was to investigate clinical characteristics of HAIs caused by the PA, the prevalence of various drug-resistant phenotypes of this pathogen, and risk factors for their occurrence. Prolonged ICU stay and previous carbapenem administration were independent risk factors for HAIs caused by carbapenem-resistant PA, while HAIs caused by multidrug-resistant PA were more frequent in patients with prolonged stay in an ICU, who were previously hospitalized at another department and previously treated with aminoglycosides, fluoroquinolones or glycopeptides. The prolonged ICU stay was the only significant risk factor for HAIs caused by extensively drug-resistant PA. To decrease the incidence of HAIs caused by drug-resistant PA, a multifaceted approach is necessary, including staff education, antibiotic stewardship, improving hygiene, shortening hospitalization, and minimizing exposure to invasive medical procedures/devices.

Post-Prescription Review with Threat of Infectious Disease Consultation and Sustained Reduction in Meropenem Use Over Four Years

BACKGROUND

Following a meropenem shortage, we implemented a post-prescription review with feedback (PPRF) in November 2015 with mandatory infectious disease (ID) consultation for all meropenem and imipenem courses > 72 hours. Providers were made aware of the policy via an electronic alert at the time of ordering.

METHODS

A retrospective study was conducted at the University of Washington Medical Center (UWMC) and Harborview Medical Center (HMC) to evaluate the impact of the policy on antimicrobial consumption and clinical outcomes pre- and post-intervention during a 6-year period. Antimicrobial use was tracked using days of therapy (DOT) per 1,000 patient-days, and data were analyzed by an interrupted time series.

RESULTS

There were 4,066 and 2,552 patients in the pre- and post-intervention periods, respectively. Meropenem and imipenem use remained steady until the intervention, when a marked reduction in DOT/1,000 patient-days occurred at both hospitals (UWMC: percentage change -72.1%, (95% CI -76.6, -66.9), P & 0.001; HMC: percentage change -43.6%, (95% CI -59.9, -20.7), P = 0.001). Notably, although the intervention did not address antibiotic use until 72 hours after initiation, there was a significant decline in meropenem and imipenem initiation ("first starts") in the post-intervention period, with a 64.9% reduction (95% CI 58.7, 70.2; P &0.001) at UWMC and 44.7% reduction (95% CI 28.1, 57.4; P & 0.001) at HMC.

CONCLUSIONS

Mandatory ID consultation and PPRF for meropenem and imipenem beyond 72 hours resulted in a significant and sustained reduction in the use of these antibiotics and notably impacted their up-front usage.

β-Lactam allergy and risk of multidrug-resistant bacteria in the intensive care unit: A cohort study

Patients identified as allergic to β-lactams are frequently exposed to treatment with broad-spectrum antibiotics. However, the risk of carriage of extended-spectrum β-lactamase (ESBL)-producing isolates in this population has been poorly investigated. The aim of this study was to evaluate the characteristics and clinical outcomes of patients admitted to the intensive care unit (ICU) with and without declared β-lactam allergy at admission. A retrospective monocentric study was performed including adult patients admitted to the ICU between 2007 and 2012. The presence of multidrug-resistant bacteria was documented in rectal and nasal swabs at admission and discharge. Patients labelled allergic to β-lactams and unlabelled patients were compared. Patients labelled allergic had significantly higher rates of ESBL at admission (13.3% vs. 4.3%; P = 0.0220) and discharge (20.0% vs. 9.0%; P = 0.0460) compared with unlabelled patients, but no significant difference in rates of ESBL acquisition in the ICU was detected. No differences in mortality, duration of hospitalisation or typical risk factors for ESBL acquisition (intubation, central venous catheter and duration of hospitalisation) were reported. No differences in carriage of methicillin-resistant Staphylococcus aureus were detected. This study showed that patients with declared β-lactam allergy had a higher risk of ESBL carriage at ICU admission and discharge.

Inapropriate use of antibiotics effective against gram positive microorganisms despite restrictive antibiotic policies in ICUs: a prospective observational study

Background

Gram-positive spectrum antibiotics such as vancomycin, teicoplanin, daptomycin, and linezolid are frequently used in empirical treatment combinations in critically ill patients. Such inappropriate and unnecessary widespread use, leads to sub-optimal utilisation. However they are covered by the antibiotics restriction programme. This prospective observational study, evaluates gram-positive anti-bacterial utilisations in intensive care units (ICUs) with various evaluation criteria, to determine the frequency of inappropriate usage and the intervention targets required to ensure optimum use.

Methods

This clinical study was conducted prospectively between 01.10.2018 and 01.10.2019 in the medical and surgical ICUs of Gazi University Faculty of Medicine Hospital, Turkey. The total bed capacity was 55. Patients older than 18 years and who were prescribed gram-positive spectrum antibiotics (vancomycin, teicoplanin, linezolid, and daptomycin) were included. Patients under this age or immunosuppressed patients (neutropenic,- HIV-infected patients with hematologic or solid organ malignancies) were not included in the study. During the study period, 200 treatments were evaluated in 169 patients. The demographic and clinical features of the patients were recorded. Besides observations by the clinical staff, the treatments were recorded and evaluated by two infectious diseases specialists and two clinical pharmacists at 24-h intervals from the first day to the last day of treatment.

SPSS software for Windows, (version 17, IBM, Armonk, NY) was used to analyse the data. Categorical variables were presented as number and percentage, and non-categorical variables were presented as mean ± standard deviation.

Results

It was found that inappropriate gram-positive antibiotic use in ICUs was as high as 83% in terms of non-compliance with the selected quality parameters. Multivariate analysis was performed to evaluate the factors associated with inappropriate antibiotic use, increased creatinine levels were found to increase the risk of such use.

Conclusions

In spite of the restricted antibiotics programme, inappropriate antibiotic use in ICUs is quite common. Thus, it is necessary to establish local guidelines in collaboration with different disciplines for the determination and follow-up of de-escalation of such use and optimal treatment doses.

Impact of an Antimicrobial Stewardship Program on Resistance to Fluoroquinolones of Urinary Enterobacteriaceae Isolated From Nursing Home Residents: A Retrospective Cohort Study

OBJECTIVES

This study investigated the impact of an antimicrobial stewardship program on fluoroquinolone (FLQ) resistance in urinary Enterobacteriaceae isolated from residents of 3 French nursing homes.

DESIGN

A multicentric retrospective before-and-after study was conducted.

SETTING AND PARTICIPANTS

All the first urinary Enterobacteriaceae isolates obtained from nursing home residents were included. Two time frames were analyzed: 2013-2015 and 2016-2017.

METHODS

The antimicrobial stewardship program started in 2015 and was based on (1) 1-day training for use of an "antimicrobial stewardship kit for nursing homes;" and (2) daily support and training of the coordinating physician by an antibiotic mobile team (AMT) in 2 of 3 nursing homes.

RESULTS

Overall, 338 urinary isolates were analyzed. Escherichia coli was the most frequent species (212/338, 63%). A significant reduction of resistance to ofloxacin was observed between 2013-2015 and 2016-2017 in general (Δ = -16%, P = .004) and among isolates obtained from patients hospitalized in the county nursing home with AMT support (Δ = -28%, P < .01). A nonstatistically significant reduction in ofloxacin resistance was also observed in the hospital nursing home with AMT support (Δ = -18%, P = .06).

CONCLUSIONS AND IMPLICATIONS

Our antimicrobial stewardship program resulted in a decrease in resistance to FLQ among urinary Enterobacteriaceae isolated from nursing home residents. The support of an AMT along with continuous training of the coordinating physician seems to be an important component to ensure efficacy of the intervention.

Variable impact of an antimicrobial stewardship programme in three intensive care units: time-series analysis of 2012-2017 surveillance data

BACKGROUND

Preprescription authorization (PPA) and postprescription review with feedback (PPRF) were successively implemented in 2012 and 2016 in our 1500-bed hospital.

AIM

The impact of PPA and PPRF on carbapenems use and resistance levels of Pseudomonas aeruginosa was assessed in three intensive care units (ICUs).

METHODS

Carbapenems use (in DDDs/1000 occupied bed-days) and resistance of P. aeruginosa (percentage of non-susceptible (I+R) isolates to imipenem and/or meropenem) were analysed using a controlled interrupted time-series method. Two periods were compared: 2012-2015 (PPA) and 2016-2017 (PPA+PPRF). Models were adjusted on the annual incidence of extended-spectrum β-lactamase-producing enterobacteriacae.

FINDINGS

Carbapenem use was stable over the PPA period in all ICUs, with a significant change of slope over the PPA+PPRF period only in ICU1 (β2 = -12.8, 95% confidence interval (CI) = -19.5 to -6.1). There was a switch from imipenem to meropenem during the PPA period in all three units. Resistances of P. aeruginosa were stable over the study period in ICU1 and ICU2, and significantly decreased over the PPA+PPRF period in ICU3 (β2 = -0.18, CI = -0.3 to -0.03).

CONCLUSION

In real-life conditions and with the same antimicrobial stewardship programme (AMSP) led by a single team, the impact of PPRF was heterogeneous between ICUs. Factors driving the impact of AMSPs should be further assessed in comparable settings through real-life data, to target where they could prove cost-effective.

Trimetoprim-sulfametoxazole in ventilator-associated pneumonia: a cohort study

To evaluate the effectiveness of trimetoprim-sulfametoxazole (TMP-SMX) for treatment of ventilator-associated pneumonia (VAP). A retrospective cohort study including patients with VAP from 2011 to 2017. Two groups were analysed: TMP-SMX group, including patients who had received TMP-SMX (as first-line and as de-escalation), and No-TMP-SMX group, including patients who had not received TMP-SMX treatment. Primary clinical outcome was mortality at 30 days from starting the antibiotic treatment (T30). Secondary outcomes were mortality at end of treatment (EoT), day survival at T30, and acquisition of multidrug-resistant bacteria during hospitalization in intensive care unit. Eighty cases of VAP were included and devised into two groups: No-TMP-SMX (31/80; 39%) and TMP-SMX (49/80; 61%). Univariate analysis showed no significant differences were found when the TMP-SMX group was compared with the No-TMP-SMX group, except for frequency of male gender (p = 0.025). No significant statistical correlations between mortality at T30 and individual factors were detected by the multivariate model. No cases of either severe allergy or Clostridium difficile disease were reported in the TMP-SMX and No-TMP-SMX groups. TMP-SMX treatment was not associated with higher mortality at EoT and T30 in comparison with the No-TMP-SMX group. TMP-SMX had a good safety profile, in terms of ecology (acquisition of MDR bacteria and Clostridium difficile disease) and clinical management (no allergy events).