Non-adherence to guidelines: an avoidable cause of failure of empirical antimicrobial therapy in the presence of difficult-to-treat bacteria

Evaluating the potential for respiratory metagenomics to improve treatment of secondary infection and detection of nosocomial transmission on expanded COVID-19 intensive care units

BACKGROUND

Clinical metagenomics (CMg) has the potential to be translated from a research tool into routine service to improve antimicrobial treatment and infection control decisions. The SARS-CoV-2 pandemic provides added impetus to realise these benefits, given the increased risk of secondary infection and nosocomial transmission of multi-drug-resistant (MDR) pathogens linked with the expansion of critical care capacity.

METHODS

CMg using nanopore sequencing was evaluated in a proof-of-concept study on 43 respiratory samples from 34 intubated patients across seven intensive care units (ICUs) over a 9-week period during the first COVID-19 pandemic wave.

RESULTS

An 8-h CMg workflow was 92% sensitive (95% CI, 75-99%) and 82% specific (95% CI, 57-96%) for bacterial identification based on culture-positive and culture-negative samples, respectively. CMg sequencing reported the presence or absence of β-lactam-resistant genes carried by Enterobacterales that would modify the initial guideline-recommended antibiotics in every case. CMg was also 100% concordant with quantitative PCR for detecting Aspergillus fumigatus from 4 positive and 39 negative samples. Molecular typing using 24-h sequencing data identified an MDR-K. pneumoniae ST307 outbreak involving 4 patients and an MDR-C. striatum outbreak involving 14 patients across three ICUs.

CONCLUSION

CMg testing provides accurate pathogen detection and antibiotic resistance prediction in a same-day laboratory workflow, with assembled genomes available the next day for genomic surveillance. The provision of this technology in a service setting could fundamentally change the multi-disciplinary team approach to managing ICU infections. The potential to improve the initial targeted treatment and rapidly detect unsuspected outbreaks of MDR-pathogens justifies further expedited clinical assessment of CMg.

Identification of Streptococcus pneumoniae in hospital-acquired pneumonia in adults

Hospital-acquired pneumonia (HAP) is often more severe and life-threatening than community-acquired pneumonia (CAP). The role of Streptococcus pneumoniae in CAP is well-understood, but its role in HAP is unclear. The objective of this study was to summarize the available literature on the prevalence of S. pneumoniae in HAP episodes. We searched MEDLINE for peer-reviewed articles on the microbiology of HAP in individuals aged ≥18 years, published between 2008 and 2018. We calculated pooled estimates of the prevalence of S. pneumoniae in episodes of HAP using a random-effects, inverse-variance-weighted meta-analysis. Forty-seven of 1908 articles met the inclusion criteria. Bacterial specimen isolation techniques for microbiologically defined HAP episodes included bronchoalveolar lavage, protective specimen brush, tracheobronchial aspirate and sputum, as well as blood culture. Culture was performed in all studies; five studies also used urine antigen detection (5/47; 10.6%). S. pneumoniae was identified in 5.1% (95% confidence interval (CI): 3.8-6.6%) of microbiologically defined HAP episodes (N = 20), with 5.4% (95% CI: 4.3-6.7%, N = 29) in ventilator-associated HAP and 6.0% (95% CI: 4.1-8.8%, N = 6) in non-ventilator-associated HAP. S. pneumoniae was identified in 5.3% (95% CI: 4.5-6.3%) of HAP occurring in the intensive care unit (ICU, N = 41) and in 5.6% (95% CI: 3.3-9.5%, N = 5) outside the ICU. A higher proportion of early-onset HAP (10.3%; 95% CI: 8.3-12.8%, N = 16) identified S. pneumoniae as compared with late-onset HAP (3.3%; 95% CI: 2.5-4.4%, N = 16). In conclusion, S. pneumoniae was identified by culture in 5.1% of microbiologically defined HAP episodes. The importance of HAP as part of the disease burden caused by S. pneumoniae merits further research.

Bacterial sepsis : Diagnostics and calculated antibiotic therapy

The mortality of patients with sepsis and septic shock is still unacceptably high. An effective calculated antibiotic treatment within 1 h of recognition of sepsis is an important target of sepsis treatment. Delays lead to an increase in mortality; therefore, structured treatment concepts form a rational foundation, taking relevant diagnostic and treatment steps into consideration. In addition to the assumed infection and individual risks of each patient, local resistance patterns and specific problem pathogens must be taken into account during the selection of anti-infective treatment. Many pathophysiologic alterations influence the pharmacokinetics (PK) of antibiotics during sepsis. The principle of standard dosing should be abandoned and replaced by an individual treatment approach with stronger weighting of the pharmacokinetics/pharmacodynamics (PK/PD) index of the substance groups. Although this is not yet the clinical standard, prolonged (or continuous) infusion of β‑lactam antibiotics and therapeutic drug monitoring (TDM) can help to achieve defined PK targets. Prolonged infusion is sufficient without TDM, but for continuous infusion, TDM is generally necessary. A further argument for individual PK/PD-oriented antibiotic approaches is the increasing number of infections due to multidrug-resistant (MDR) pathogens in the intensive care unit. For effective treatment, antibiotic stewardship teams (ABS teams) are becoming more established. Interdisciplinary cooperation of the ABS team with infectious disease (ID) specialists, microbiologists, and clinical pharmacists leads not only to rational administration of antibiotics, but also has a positive influence on treatment outcome. The gold standards for pathogen identification are still culture-based detection and microbiologic resistance testing for the various antibiotic groups. Despite the rapid investigation time, novel polymerase chain reaction(PCR)-based procedures for pathogen identification and resistance determination are currently only an adjunct to routine sepsis diagnostics, due to the limited number of studies, high costs, and limited availability. In complicated septic courses with multiple anti-infective therapies or recurrent sepsis, PCR-based procedures can be used in addition to treatment monitoring and diagnostics. Novel antibiotics represent potent alternatives in the treatment of MDR infections. Due to the often defined spectrum of pathogens and the practically (still) absent resistance, they are suitable for targeted treatment of severe MDR infections (therapy escalation). (Contribution available free of charge by "Free Access" [ https://link.springer.com/article/10.1007/s00101-017-0396-z ].).

[Bacterial sepsis : Diagnostics and calculated antibiotic therapy]

The mortality of patients with sepsis and septic shock is still unacceptably high. An effective antibiotic treatment within 1 h of recognition of sepsis is an important target of sepsis treatment. Delays lead to an increase in mortality; therefore, structured treatment concepts form a rational foundation, taking relevant diagnostic and treatment steps into consideration. In addition to the assumed focus and individual risks of each patient, local resistance patterns and specific problem pathogens must be taken into account for selection of anti-infection treatment. Many pathophysiological alterations influence the pharmacokinetics of antibiotics during sepsis. The principle of standard dosing should be abandoned and replaced by an individual treatment approach with stronger weighting of the pharmacokinetics/pharmacodynamics (PK/PD) index of the substance groups. Although this is not yet the clinical standard, prolonged (or continuous) infusion of beta-lactam antibiotics and therapeutic drug monitoring (TDM) can help to achieve defined PK targets. Prolonged infusion is sufficient without TDM but for continuous infusion TDM is basically necessary. A further argument for individual PK/PD-oriented antibiotic approaches is the increasing number of infections due to multidrug resistant pathogens (MDR) in the intensive care unit. For effective treatment antibiotic stewardship teams (ABS team) are becoming more established. Interdisciplinary cooperation of the ABS team with infectiologists, microbiologists and clinical pharmacists leads not only to a rational administration of antibiotics but also has a positive influence on the outcome. The gold standards for pathogen detection are still culture-based detection and microbiological resistance testing for the various antibiotic groups. Despite the rapid investigation time, novel polymerase chain reaction (PCR)-based procedures for pathogen identification and resistance determination, are currently only an adjunct to routine sepsis diagnostics due to the limited number of studies, high costs and limited availability. In complicated septic courses with multiple anti-infective treatment or recurrent sepsis, PCR-based procedures can be used in addition to therapy monitoring and diagnostics. Novel antibiotics represent potent alternatives in the treatment of MDR infections. Due to the often defined spectrum of pathogens and the practically absent resistance, they are suitable for targeted treatment of severe MDR infections (therapy escalation).

Perceptions and behaviours of infectious diseases physicians when managing urinary tract infections due to MDR organisms

OBJECTIVES

The objective of this study was to attain a better understanding of infectious diseases (ID) physicians' experience with MDR organism (MDRO) urinary tract infections (UTIs) by means of a survey on disease perception, diagnostic management and treatment preferences.

METHODS

A nine-question survey was developed and distributed to members of the North American Emerging Infections Network (EIN) in September 2013.

RESULTS

Seven hundred and fourteen out of 1461 EIN members responded to the survey (49%). The responses of 603 responders were studied. Most providers perceived an increase in the incidence of MDRO UTIs over the past 3 years (75% of adult ID responders and 63% of paediatric ID responders). One hundred and thirty-four (22%) responders prefer intravenous over oral administration of antimicrobials when both are available, 171 (28%) prefer longer durations of therapy when comparing an MDRO with a susceptible isolate of the same species and 142 (24%) order a repeat urine culture as 'proof of cure' after treating an MDRO UTI. Nevertheless, 530 (88%) responders perceived MDRO UTIs to be of similar severity as non-MDRO UTIs. Fifty-five percent of providers prescribed fosfomycin for MDRO UTI at least once; the most common prescribing pattern (among a wide spectrum of approaches) was a single dose (16%).

CONCLUSIONS

Future studies on MDRO UTIs should clarify the role of resistance in patient outcomes and the comparative efficacy of different antimicrobials. Of particular interest is fosfomycin, which is unrelated to other antibiotic classes and may take a more prominent role in treating MDRO cystitis.

Relationships within inpatient physician housestaff teams and their association with hospitalized patient outcomes

IMPORTANCE

Improving inpatient care delivery has historically focused on improving individual components of the system. Applying the complexity science framework to clinical systems highlights the important role of relationships among providers in influencing system function and clinical outcomes.

OBJECTIVE

To understand whether inpatient medical physician teams can be differentiated based on the relationships among team members, and whether these relationships are associated with patient outcomes, including length of stay (LOS), unnecessary length of stay (ULOS), and complication rates.

DESIGN

Eleven inpatient medicine teams were observed daily during attending rounds for 2- to 4-week periods from September 2008 through June 2011. Detailed field notes were taken regarding patient care activities, team behaviors, and patient characteristics and outcomes. Behaviors were categorized using the Lanham relationship framework, giving each team a relationship score. We used factor analysis to assess the pattern of relationship characteristics and assessed the association between relationship characteristics and patient outcomes.

SETTING

Observations occurred at the Audie L. Murphy Veterans Affairs Hospital and University Hospital in San Antonio, Texas.

PARTICIPANTS

Physicians were chosen based on rotation schedules, experience, and time of year. Patients were included based on their admission to the inpatient medicine teams that were being observed.

MAIN MEASURES

Relationship scores were based on the presence or absence of 7 relationship characteristics. LOS, ULOS, and complication rates were assessed based on team discussions and chart review. The association between relationships and outcomes was assessed using the Kruskal-Wallis rank sum test.

RESULTS

We observed 11 teams over 352.9 hours, observing 1941 discussions of 576 individual patients. Teams exhibited a range of 0 to 7 relationship characteristics. Relationship scores were significantly associated with complication rates, and presence of trust and mindfulness among teams was significantly associated with ULOS and complication rates.

CONCLUSIONS

Our findings are an important step in understanding the impact of relationships on the outcomes of hospitalized medical patients. This understanding could expand the scope of interventions to improve hospital care to include not only process improvement but also relationships among providers.

Improving outcomes of hospitalized patients: the Physician Relationships, Improvising, and Sensemaking intervention protocol

BACKGROUND

Our goal is to improve the safety and effectiveness of inpatient care. Rather than focus on improving process of care, we focus on the social structure within physician teams. We have developed the Physician Relationships, Improvising, and Sensemaking (PRISm) intervention to improve the way physician teams round, enabling them to better relate, make sense of their patients' conditions, and improvise in uncertain clinical situations. We are currently studying the impact of PRISm on adverse events and complications in hospitalized patients. This manuscript describes the PRISm intervention.

METHODS/DESIGN

PRISm is a structured communication tool consisting of three components: daily briefings before rounds; use of the Situation, Task, Intent, Concern, and Calibrate (STICC) framework during rounds as part of the discussion of individual patients; and debriefings after rounds. We are implementing the PRISm intervention on eight inpatient medical and surgical physician teams in the South Texas Veterans Health Care System. We are assessing PRISm impact on the way team members relate to each other, round, and discuss patients through pre- and post-implementation observations and surveys. We are also assessing PRISm impact on complications and adverse events. Finally, we are interviewing physicians regarding their experience using the intervention.

DISCUSSION

Our results will allow us to begin to understand the potential impact of interventions designed to improve how providers relate to each other, improvise, and make sense of what is happening as a strategy for improving inpatient care. Our in-depth data collection will enable us to assess how relationships, improvising, and sensemaking influence patient outcomes, potentially through creating shared mental models or enhancing distributed cognition during clinical reasoning. Finally, our results will lay the groundwork for larger implementation studies to improve clinical outcomes through improving how providers, and providers, patients, and caregivers, relate.

De-escalation versus continuation of empirical antimicrobial treatment in severe sepsis: a multicenter non-blinded randomized noninferiority trial

BACKGROUND

In patients with severe sepsis, no randomized clinical trial has tested the concept of de-escalation of empirical antimicrobial therapy. This study aimed to compare the de-escalation strategy with the continuation of an appropriate empirical treatment in those patients.

METHODS

This was a multicenter non-blinded randomized noninferiority trial of patients with severe sepsis who were randomly assigned to de-escalation or continuation of empirical antimicrobial treatment. Recruitment began in February 2012 and ended in April 2013 in nine intensive care units (ICUs) in France. Patients with severe sepsis were assigned to de-escalation (n = 59) or continuation of empirical antimicrobial treatment (n = 57). The primary outcome was to measure the duration of ICU stay. We defined a noninferiority margin of 2 days. If the lower boundary of the 95 % confidence interval (CI) for the difference in patients assigned to the de-escalation group was less than 2 days, as compared with that of patients assigned to the continuation group, de-escalation was considered to be noninferior to the continuation strategy. Secondary outcomes included mortality at 90 days, occurrence of organ failure, number of superinfections, and number of days with antibiotics during the ICU stay.

RESULTS

The median duration of ICU stay was 9 [interquartile range (IQR) 5-22] days in the de-escalation group and 8 [IQR 4-15] days in the continuation group, respectively (P = 0.71). The mean difference was 3.4 (95 % CI -1.7 to 8.5). A superinfection occurred in 16 (27 %) patients in the de-escalation group and six (11 %) patients in the continuation group (P = 0.03). The numbers of antibiotic days were 9 [7-15] and 7.5 [6-13] in the de-escalation group and continuation group, respectively (P = 0.03). Mortality was similar in both groups.

CONCLUSION

As compared to the continuation of the empirical antimicrobial treatment, a strategy based on de-escalation of antibiotics resulted in prolonged duration of ICU stay. However, it did not affect the mortality rate.

Biofilm-dependent airway infections: a role for ambroxol?

Biofilms are a key factor in the development of both acute and chronic airway infections. Their relevance is well established in ventilator associated pneumonia, one of the most severe complications in critically ill patients, and in cystic fibrosis, the most common lethal genetic disease in Caucasians. Accumulating evidence suggests that biofilms could have also a role in chronic obstructive pulmonary disease and their involvement in bronchiectasis has been proposed as well. When they grow in biofilms, microorganisms become multidrug-resistant. Therefore the treatment of biofilm-dependent airway infections is problematic. Indeed, it still largely based on measures aiming to prevent the formation of biofilms or remove them once that they are formed. Here we review recent evidence suggesting that the mucokinetic drug ambroxol has specific anti-biofilm properties. We also discuss how additional pharmacological properties of this drug could be beneficial in biofilm-dependent airway infections. Specifically, we review the evidence showing that: 1-ambroxol exerts anti-inflammatory effects by inhibiting at multiple levels the activity of neutrophils, and 2-it improves mucociliary clearance by interfering with the activity of airway epithelium ion channels and transporters including sodium/bicarbonate and sodium/potassium/chloride cotransporters, cystic fibrosis transmembrane conductance regulator and aquaporins. As a whole, the data that we review here suggest that ambroxol could be helpful in biofilm-dependent airway infections. However, considering the limited clinical evidence available up to date, further clinical studies are required to support the use of ambroxol in these diseases.

The clinical impact of multidrug-resistant gram-negative bacilli in the management of septic shock

Multi-antibiotic drug-resistant (MDR) gram-negative bacilli are becoming a major threat to the standard care of septic patients. Empiric antimicrobial drug regimens to cover likely bacterial pathogens have to be altered in keeping with the spread of MDR pathogens in the health care setting and in the community. Reliable antibiotics for broad spectrum coverage for sepsis such as extended spectrum β-lactam antibiotics, carbapenems, and fluoroquinolones can no longer be counted upon to provide activity against a range of common, virulent pathogens that cause sepsis. In some regions of Asia, South America, and Eastern Europe in particular, MDR pathogens have become a major concern, necessitating the use of potentially toxic and costly antibiotic combinations as initial antibiotic therapy for septic shock. In this brief review, we will focus on the emergence of MDR gram-negative pathogens, resistance mechanisms, and suggest some management and prevention strategies against MDR pathogens.

Inappropriate antibiotic use due to decreased compliance with a ventilator-associated pneumonia computerized clinical pathway: implications for continuing education and prospective feedback

STUDY OBJECTIVE

To assess the impact of noncompliance with a ventilator-associated pneumonia (VAP) computerized clinical pathway (CCP) on antibiotic use after removal of prospective antibiotic stewardship resources.

DESIGN

Retrospective, observational, quasi-experimental study.

SETTING

Three intensive care units (medical, surgical, and neurotrauma) in a large, tertiary care hospital.

PATIENTS

A total of 136 patients with culture-positive VAP; 72 were treated from September 2006-August 2007 (period 1), during which use of the CCP was mandatory along with aggressive stewardship support, and 64 were treated from September 2009-April 2010 (period 2), during which use of the CCP was voluntary.

MEASUREMENTS AND MAIN RESULTS

Compliance with use of the CCP was 100% during period 1 and 44% (28/64 patients) during period 2. For the 36 patients (56%) whose antibiotic selection did not comply with the CCP, empiric antibiotics were selected by provider discretion. Most patients had late-onset VAP and were similar with respect to age, sex, and comorbidities between the two periods. Staphylococcus aureus (11-17% methicillin-resistant S. aureus) and Pseudomonas aeruginosa were the most common pathogens during both periods. The proportion of patients with appropriate antibiotics within 24 hours of VAP identification was not significantly different between period 1 (70.8%) and period 2 (56.3%, p=0.112). During period 2, patients who were treated according to the CCP were more likely to receive appropriate antibiotic therapy compared with patients treated according to provider discretion (82.1% vs 36.1%, p ≤ 0.001). Time to appropriate therapy was also shorter for patients treated according to the CCP (mean ± SD 0.43 ± 1.14 vs 1.29 ± 1.36 days, p=0.003). Treatment with the CCP was the only variable significantly associated with appropriate antibiotic therapy (odds ratio 4.8, 95% confidence interval 2.1-10.9). Mortality was not significantly different between period 1 and period 2, and only Acute Physiology and Chronic Health Evaluation II score and admission with a head injury were predictive of death. Finally, a greater proportion of patients treated with the CCP were de-escalated from anti- Pseudomonas β-lactams (85.0% vs 33.3%, p=0.006) when they were not necessary.

CONCLUSION

These data highlight the importance of continued stewardship resources after CCP implementation to ensure compliance and to maximize antibiotic stewardship outcomes.

Overview of antimicrobial therapy in intensive care units

In the management of a patient with severe sepsis, it is important to suspect the infection early, to collect samples immediately after diagnosis and to promptly initiate a broad-spectrum antibiotic treatment. The choice of this empirical antimicrobial therapy should be based on host characteristics, site of infection, local ecology and pharmacokinetics/pharmacodynamics of antibiotics. In severe infection, guidelines recommend the use of a combination of antibiotics. After results of cultures are obtained, treatment should be re-evaluated to either de-escalate or escalate the antibiotic prescription. This is associated with optimal costs, decreased incidence of superinfection and minimal development of antimicrobial resistance. All these steps should rely on written protocols, and the compliance to these protocols should be continuously monitored in order to detect violations and implement corrective procedures.

[Antibiotic treatment of nosocomial pneumonia]

Nosocomial pneumonia is one of the most common infectious diseases acquired in hospital and is often caused by resistant pathogens. For treatment of nosocomial pneumonia an appropriate initial antibiotic therapy is essential and exact knowledge of the specific pathogen spectrum is essential for the correct choice of the empirically calculated antibiotics. In line with a critical reevaluation of the primary treatment, pathogen-specific de-escalation therapy, a diagnosis of possible pulmonary complications (e. g. pleural empyema) and the identification and appropriate rehabilitation measures of non-pulmonary infections are necessary. To attain the best possible outcome the respective therapy concept needs to be adjusted to the individual risk characteristics. Appropriate initial antibiotic therapy, duration of mechanical ventilation and comorbidities are the key factors for patient outcome. This approach helps to avoid the development of resistant pathogens and saves economic resources.