Rapid multiplex PCR panel for pneumonia in hospitalised patients with suspected pneumonia in the USA: a single-centre, open-label, pragmatic, randomised controlled trial

BACKGROUND

The clinical utility of rapid multiplex respiratory specimen PCR panels for pneumonia for patients with suspected pneumonia is undefined. We aimed to compare the effect of the BioFire FilmArray pneumonia panel (bioMérieux, Salt Lake City, UT, USA) with standard of care testing on antibiotic use in a real-world hospital setting.

METHODS

We conducted a single-centre, open-label, pragmatic, randomised controlled trial at the Mayo Clinic, Rochester, MN, USA. Hospitalised patients (aged ≥18 years) with suspected pneumonia, from whom expectorated or induced sputum, tracheal secretions, or bronchoalveolar lavage fluid respiratory culture samples (one per individual) could be collected during index hospitalisation, were eligible for inclusion. Samples from eligible participants were randomly assigned (1:1) with a computerised tool to undergo testing with either the BioFire FilmArray pneumonia panel, conventional culture, and antimicrobial susceptibility testing (intervention group) or conventional culture and antimicrobial susceptibility testing alone (control group). Antimicrobial stewardship review in both groups involved an assessment and recommendations for antibiotic modifications based on clinical data and the results from the BioFire FilmArray pneumonia panel, conventional culture, or both. The primary outcome was median time to first antibiotic modification (ie, escalation or de-escalation of antibiotics against Gram-negative and Gram-positive bacteria) within 96 h of randomisation, assessed with the Wilcoxon rank-sum test and analysed in a modified intention-to-treat population. This trial is registered with ClinicalTrials.gov (NCT05937126).

FINDINGS

Between Sept 15, 2020, and Sept 19, 2022, 1547 patients were screened for eligibility, of whom 1181 (76·3%) were randomly assigned: 582 (49·3%) to the intervention group and 599 (50·7%) to the control group. In total, 1152 participants were included in the modified intention-to-treat analysis, 589 (51·1%) in the control group and 563 (48·9%) in the intervention group. For the modified intention-to-treat population, median time to any first antibiotic modification was 20·4 h (95% CI 18·0-20·4) in the intervention group and 25·8 h (22·0-28·7) in the control group (p=0·076). Median time to any antibiotic escalation was 13·8 h (9·2-19·0) in the intervention group and 24·1 h (19·5-29·6) in the control group (p=0·0022). Median time to escalation of antibiotics against Gram-positive organisms was 10·3 h (6·2-30·9) in the intervention group and 24·6 h (19·5-37·2) in the control group (p=0·044); median time to escalation of antibiotics against Gram-negative organisms was 17·3 h (10·8-23·3) in the intervention group and 27·2 h (21·3-33·9) in the control group (p=0·010). Median time to any antibiotic de-escalation did not differ between groups (p=0·37). Median time to first de-escalation of antibiotics against Gram-positive organisms was 20·7 h (17·8-24·0) in the intervention group and 27·8 h (22·9-33·0) in the control group (p=0·015); median time to first de-escalation of antibiotics against Gram-negative organisms did not differ between groups (p=0·46).

INTERPRETATION

Clinical use of the BioFire FilmArray pneumonia panel might lead to faster antibiotic escalations, including for Gram-negative or Gram-positive bacteria, and faster antibiotic de-escalations directed at Gram-positive bacteria. Additional research is needed regarding antimicrobial de-escalation, especially when antibiotics with broad Gram-negative spectrum are being used, by use of rapid diagnostics in patients with lower respiratory tract infection.

FUNDING

bioMérieux.

Infections in decompensated cirrhosis: Pathophysiology, management, and research agenda

Bacterial infections in patients with cirrhosis lead to a 4-fold increase in mortality. Immune dysfunction in cirrhosis further increases the risk of bacterial infections, in addition to alterations in the gut microbiome, which increase the risk of pathogenic bacteria. High rates of empiric antibiotic use contribute to increased incidence of multidrug-resistant organisms and further increases in mortality. Despite continous advances in the field, major unknowns regarding interactions between the immune system and the gut microbiome and strategies to reduce infection risk and improve mortality deserve further investigation. Here, we highlight the unknowns in these major research areas and make a proposal for a research agenda to move toward improving disease progression and outcomes in patients with cirrhosis and infections.

Heterogeneity, Bayesian thinking, and phenotyping in critical care: A primer

PURPOSE

To familiarize clinicians with the emerging concepts in critical care research of Bayesian thinking and personalized medicine through phenotyping and explain their clinical relevance by highlighting how they address the issues of frequent negative trials and heterogeneity of treatment effect.

SUMMARY

The past decades have seen many negative (effect-neutral) critical care trials of promising interventions, culminating in calls to improve the field's research through adopting Bayesian thinking and increasing personalization of critical care medicine through phenotyping. Bayesian analyses add interpretive power for clinicians as they summarize treatment effects based on probabilities of benefit or harm, contrasting with conventional frequentist statistics that either affirm or reject a null hypothesis. Critical care trials are beginning to include prospective Bayesian analyses, and many trials have undergone reanalysis with Bayesian methods. Phenotyping seeks to identify treatable traits to target interventions to patients expected to derive benefit. Phenotyping and subphenotyping have gained prominence in the most syndromic and heterogenous critical care disease states, acute respiratory distress syndrome and sepsis. Grouping of patients has been informative across a spectrum of clinically observable physiological parameters, biomarkers, and genomic data. Bayesian thinking and phenotyping are emerging as elements of adaptive clinical trials and predictive enrichment, paving the way for a new era of high-quality evidence. These concepts share a common goal, sifting through the noise of heterogeneity in critical care to increase the value of existing and future research.

CONCLUSION

The future of critical care medicine will inevitably involve modification of statistical methods through Bayesian analyses and targeted therapeutics via phenotyping. Clinicians must be familiar with these systems that support recommendations to improve decision-making in the gray areas of critical care practice.

Global, regional, and national incidence and mortality burden of non-COVID-19 lower respiratory infections and aetiologies, 1990-2021: a systematic analysis from the Global Burden of Disease Study 2021

BACKGROUND

Lower respiratory infections (LRIs) are a major global contributor to morbidity and mortality. In 2020-21, non-pharmaceutical interventions associated with the COVID-19 pandemic reduced not only the transmission of SARS-CoV-2, but also the transmission of other LRI pathogens. Tracking LRI incidence and mortality, as well as the pathogens responsible, can guide health-system responses and funding priorities to reduce future burden. We present estimates from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 of the burden of non-COVID-19 LRIs and corresponding aetiologies from 1990 to 2021, inclusive of pandemic effects on the incidence and mortality of select respiratory viruses, globally, regionally, and for 204 countries and territories.

METHODS

We estimated mortality, incidence, and aetiology attribution for LRI, defined by the GBD as pneumonia or bronchiolitis, not inclusive of COVID-19. We analysed 26 259 site-years of mortality data using the Cause of Death Ensemble model to estimate LRI mortality rates. We analysed all available age-specific and sex-specific data sources, including published literature identified by a systematic review, as well as household surveys, hospital admissions, health insurance claims, and LRI mortality estimates, to generate internally consistent estimates of incidence and prevalence using DisMod-MR 2.1. For aetiology estimation, we analysed multiple causes of death, vital registration, hospital discharge, microbial laboratory, and literature data using a network analysis model to produce the proportion of LRI deaths and episodes attributable to the following pathogens: Acinetobacter baumannii, Chlamydia spp, Enterobacter spp, Escherichia coli, fungi, group B streptococcus, Haemophilus influenzae, influenza viruses, Klebsiella pneumoniae, Legionella spp, Mycoplasma spp, polymicrobial infections, Pseudomonas aeruginosa, respiratory syncytial virus (RSV), Staphylococcus aureus, Streptococcus pneumoniae, and other viruses (ie, the aggregate of all viruses studied except influenza and RSV), as well as a residual category of other bacterial pathogens.

FINDINGS

Globally, in 2021, we estimated 344 million (95% uncertainty interval [UI] 325-364) incident episodes of LRI, or 4350 episodes (4120-4610) per 100 000 population, and 2·18 million deaths (1·98-2·36), or 27·7 deaths (25·1-29·9) per 100 000. 502 000 deaths (406 000-611 000) were in children younger than 5 years, among which 254 000 deaths (197 000-320 000) occurred in countries with a low Socio-demographic Index. Of the 18 modelled pathogen categories in 2021, S pneumoniae was responsible for the highest proportions of LRI episodes and deaths, with an estimated 97·9 million (92·1-104·0) episodes and 505 000 deaths (454 000-555 000) globally. The pathogens responsible for the second and third highest episode counts globally were other viral aetiologies (46·4 million [43·6-49·3] episodes) and Mycoplasma spp (25·3 million [23·5-27·2]), while those responsible for the second and third highest death counts were S aureus (424 000 [380 000-459 000]) and K pneumoniae (176 000 [158 000-194 000]). From 1990 to 2019, the global all-age non-COVID-19 LRI mortality rate declined by 41·7% (35·9-46·9), from 56·5 deaths (51·3-61·9) to 32·9 deaths (29·9-35·4) per 100 000. From 2019 to 2021, during the COVID-19 pandemic and implementation of associated non-pharmaceutical interventions, we estimated a 16·0% (13·1-18·6) decline in the global all-age non-COVID-19 LRI mortality rate, largely accounted for by a 71·8% (63·8-78·9) decline in the number of influenza deaths and a 66·7% (56·6-75·3) decline in the number of RSV deaths.

INTERPRETATION

Substantial progress has been made in reducing LRI mortality, but the burden remains high, especially in low-income and middle-income countries. During the COVID-19 pandemic, with its associated non-pharmaceutical interventions, global incident LRI cases and mortality attributable to influenza and RSV declined substantially. Expanding access to health-care services and vaccines, including S pneumoniae, H influenzae type B, and novel RSV vaccines, along with new low-cost interventions against S aureus, could mitigate the LRI burden and prevent transmission of LRI-causing pathogens.

FUNDING

Bill & Melinda Gates Foundation, Wellcome Trust, and Department of Health and Social Care (UK).

Optimizing Diagnosis and Management of Community-acquired Pneumonia in the Emergency Department

Pneumonia is split into 3 diagnostic categories: community-acquired pneumonia (CAP), health care-associated pneumonia, and ventilator-associated pneumonia. This classification scheme is driven not only by the location of infection onset but also by the predominant associated causal microorganisms. Pneumonia is diagnosed in over 1.5 million US emergency department visits annually (1.2% of all visits), and most pneumonia diagnosed by emergency physicians is CAP.

Impact of a pharmacy-driven MRSA nares screening protocol on vancomycin discontinuation in a tele-antimicrobial stewardship model

A pharmacist-driven protocol for methicillin-resistant Staphylococcus aureus nares screening and empiric vancomycin discontinuation was instituted in a community healthcare system utilizing a tele-antimicrobial stewardship program to reduce inappropriate use of vancomycin. The protocol and associated intervention resulted in a significant decrease in both vancomycin utilization and the rate of acute kidney injury.

Predictive value of methicillin-resistant staphylococcus aureus nasal swab in patients with COVID-19 pneumonia and secondary bacterial pneumonia

OBJECTIVE

To determine the performance measures of admission methicillin-resistant Staphylococcus aureus (MRSA) nasal swabs for MRSA bacterial pneumonia in patients co-infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

METHODS

The study included patients admitted with SARS-CoV-2-positive nasopharyngeal specimens, MRSA nasal screens, and bacterial cultures to assess secondary MRSA pneumonia.

RESULTS

293 patients and 662 microbiological cultures evaluated. Overall, the specificity (91.8% [95% CI 88.6% to 95%]) and negative predictive value (NPV 97.4% [95% CI 95.4% - 99.3%]) of MRSA nasal swabs was high. However, the sensitivity (46.2%; 95% CI 19.1% to 73.3%) and positive predictive value (PPV 20.7%; 95% CI 59.5 - 35.4%) were low. Those patients in the MRSA nasal swab negative group had a shorter median duration of linezolid therapy.

CONCLUSIONS

SARS-CoV-2 infection doesn't reduce the specificity or negative predictive value of MRSA nasal swabs for secondary MRSA pneumonia.

Novel small-molecule compound YH7 inhibits the biofilm formation of Staphylococcus aureus in a sarX-dependent manner

The emergence of antibiotic-resistant and biofilm-producing Staphylococcus aureus isolates presents major challenges for treating staphylococcal infections. Biofilm inhibition is an important anti-virulence strategy. In this study, a novel maleimide-diselenide hybrid compound (YH7) was synthesized and demonstrated remarkable antimicrobial activity against methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) in both planktonic cultures and biofilms. The minimum inhibitory concentration (MIC) of YH7 for S. aureus isolates was 16 µg/mL. Quantification of biofilms demonstrated that the sub-MIC (4 µg/mL) of YH7 significantly inhibits biofilm formation in both MSSA and MRSA. Confocal laser scanning microscopy analysis further confirmed the biofilm inhibitory potential of YH7. YH7 also significantly suppressed bacterial adherence to A549 cells. Moreover, YH7 treatment significantly inhibited S. aureus colonization in nasal tissue of mice. Preliminary mechanistic studies revealed that YH7 exerted potent biofilm-suppressing effects by inhibiting polysaccharide intercellular adhesin (PIA) synthesis, rather than suppressing bacterial autolysis. Real-time quantitative PCR data indicated that YH7 downregulated biofilm formation-related genes (clfA, fnbA, icaA, and icaD) and the global regulatory gene sarX, which promotes PIA synthesis. The sarX-dependent antibiofilm potential of YH7 was validated by constructing S. aureus NCTC8325 sarX knockout and complementation strains. Importantly, YH7 demonstrated a low potential to induce drug resistance in S. aureus and exhibited non-toxic to rabbit erythrocytes, A549, and BEAS-2B cells at antibacterial concentrations. In vivo toxicity assays conducted on Galleria mellonella further confirmed that YH7 is biocompatible. Overall, YH7 demonstrated potent antibiofilm activity supports its potential as an antimicrobial agent against S. aureus biofilm-related infections. IMPORTANCE Biofilm-associated infections, characterized by antibiotic resistance and persistence, present a formidable challenge in healthcare. Traditional antibacterial agents prove inadequate against biofilms. In this study, the novel compound YH7 demonstrates potent antibiofilm properties by impeding the adhesion and the polysaccharide intercellular adhesin production of Staphylococcus aureus. Notably, its exceptional efficacy against both methicillin-resistant and methicillin-susceptible strains highlights its broad applicability. This study highlights the potential of YH7 as a novel therapeutic agent to address the pressing issue of biofilm-driven infections.

Comparison of Methicillin-Resistant Staphylococcus aureus Nasal Screening Predictive Value in the Intensive Care Unit and General Ward

BACKGROUND

The clinical utility of methicillin-resistant Staphylococcus aureus (MRSA) nasal screening appears promising for antimicrobial stewardship programs. However, a paucity of data remains on the diagnostic performance of culture-based MRSA screen in the intensive care unit (ICU) for pneumonia and bacteremia.

OBJECTIVE

The objective of this study was to compare the predictive value of culture-based MRSA nasal screening for pneumonia and bacteremia in ICU and general ward patients.

METHODS

This multicenter, retrospective study was conducted over a 23-month period. Adult patients with MRSA nasal screening ≤48 hours of collecting a respiratory and/or blood culture with concurrent initiation of anti-MRSA therapy were included. The primary endpoint was to compare the negative predictive value (NPV) associated with culture-based MRSA nasal screening between ICU and general ward patients with suspected pneumonia.

RESULTS

A total of 5106 patients representing the ICU (n = 2515) and general ward (n = 2591) were evaluated. The NPV of the MRSA nares for suspected pneumonia was not significantly different between ICU and general ward patient populations (98.3% and 97.6%, respectively; P = 0.41). The MRSA nares screening tool also had a high NPV for suspected bacteremia in ICU (99.8%) and general ward groups (99.7%) (P = 0.56). The overall positive MRSA nares rates in the ICU and general ward patient populations were 9.1% and 8.2%, respectively (P = 0.283). Moreover, MRSA-positive respiratory and blood cultures among ICU patients were 5.8% and 0.8%, respectively.

CONCLUSION AND RELEVANCE

Our findings support the routine use of MRSA nasal screening using the culture-based method in ICU patients with pneumonia. Further research on the clinical performance for MRSA bacteremia in the ICU is warranted.

Recent updates in the development of molecular assays for the rapid identification and susceptibility testing of MRSA

INTRODUCTION

Methicillin-resistant Staphylococcus aureus (MRSA) is a frequent cause of healthcare- and community-associated infections. Nasal carriage of MRSA is a risk factor for subsequent MRSA infections. Increased morbidity and mortality are associated with MRSA infections and screening and diagnostic tests for MRSA play an important role in clinical management.

AREAS COVERED

A literature search was conducted in PubMed and supplemented by citation searching. In this article, we provide a comprehensive review of molecular-based methods for MRSA screening and diagnostic tests including individual nucleic acid detection assays, syndromic panels, and sequencing technologies with a focus on their analytical performance.

EXPERT OPINION

Molecular based-assays for the detection of MRSA have improved in terms of accuracy and availability. Rapid turnaround enables earlier contact isolation and decolonization for MRSA. The availability of syndromic panel tests that include MRSA as a target has expanded from positive blood cultures to pneumonia and osteoarticular infections. Sequencing technologies allow detailed characterizations of novel methicillin-resistance mechanisms that can be incorporated into future assays. Next generation sequencing is capable of diagnosing MRSA infections that cannot be identified by conventional methods and metagenomic next-generation sequencing (mNGS) assays will likely move closer to implementation as front-line diagnostics in the near future.

Measuring clinical outcomes of highly multiplex molecular diagnostics for respiratory infections: A systematic review and conceptual framework

Objectives

To review methodologies and outcomes reporting among these studies and to develop a conceptual framework of outcomes to assist in guiding studies and production of clinical metrics.

Data sources

PubMed and Embase from January 1, 2012, thru December 1, 2021.

Study eligibility criteria

Studies evaluating highly multiplex molecular respiratory diagnostics and their impact on either clinical or economic outcomes.

Methods

A systematic literature review (SLR) of methodologies and outcomes reporting was performed. A qualitative synthesis of identified SLRs and associated primary studies was conducted to develop conceptual framework for outcomes.

Results

Ultimately, 4 systemic literature reviews and their 12 associated primary studies were selected for review. Most primary studies included patient outcomes focusing on antimicrobial exposure changes such as antibiotic (80%) and antiviral use (50%) or occupancy changes such as hospital length of stay (60%). Economic outcomes were infrequently reported, and societal outcomes, such as antibiotic resistance impact, were absent from the reviewed literature. Qualitative evidence synthesis of reported outcomes yielded a conceptual framework of outcomes to include operational, patient, economic, and societal domains.

Conclusions

Our review highlights the significant heterogeneity in outcomes reporting among clinical impact studies for highly multiplex molecular respiratory diagnostics. Furthermore, we developed a conceptual framework of outcomes domains that may act as a guide to improve considerations in outcomes selection and reporting when evaluating clinical impact of these tests. These improvements may be important in synthesizing the evidence for informing clinical decision making, guidelines, and financial reimbursement.

Effectiveness of Extended Infection Control Measures on Methicillin-Resistant Staphylococcus aureus Infection Among Orthopaedic Patients

Purpose

The purpose of the study was to find the effectiveness of Extended Infection Control Measures (EICM) in reducing the rate of methicillin-resistant Staphylococcus aureus (MRSA) infection among orthopaedic surgery patients.

Methods

The study adopted a quasi-experimental design and was conducted in the orthopaedic units of a tertiary care hospital. This study recruited 168 orthopaedic patients and 154 healthcare professionals (HCPs). EICM included hand hygiene, decolonizing the patients and HCPS, staff education, feedback of surveillance data, treatment of high-risk and MRSA-infected patients, having separate equipment for MRSA-infected patients, and appropriate cleaning of patient's unit.

Results

The EICM effectively reduced MRSA infection from 21.2 to 6% (p < 0.001). It also resulted in improving the knowledge of HCPs in the prevention and management of MRSA infection (p < 0.001), and all colonized HCPs were successfully (100%) decolonized.

Conclusion

EICM is a promising intervention to combat MRSA infection among orthopaedic wards. Hence, it can be executed in orthopaedic wards, thereby improving the treatment quality and reducing the infection-related consequences.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43465-022-00713-5.

Clinical Utility of Dual Anterior Nares and Oropharynx MRSA Screening PCR for Patients with Suspected Pneumonia

We reviewed the electronic health records of 1,419 inpatients with anterior nares (AN) and oropharynx (OP) MRSA PCR tests. Concordance was 96.5%. In discordant cases, AN negative-OP positive results increased detection of probable MRSA pneumonia by only 0.3%. A dual testing approach has limited utility in detecting MRSA pneumonia and increases resource utilization.

Clinical utility of methicillin-resistant Staphylococcus aureus nasal polymerase chain reaction (PCR) assays beyond respiratory infections

We estimated the predictive value of methicillin-resistant Staphylococcus aureus (MRSA) nasal polymerase chain reaction (PCR) for blood, bone, and soft-tissue cultures. The specificities were 88.8%, 88.5%, and 92.7% for all cultures, blood cultures, and bone and soft-tissue cultures respectively, and the negative predictive values were 99.3%, 99.8%, and 92.7% respectively.

Prospective Nasal Screening for Methicillin-Resistant Staphylococcus aureus in Critically Ill Patients With Suspected Pneumonia

We carried out a prospective de-escalation study based on methicillin-resistant Staphylococcus aureus (MRSA) nasal cultures in intensive care unit patients with suspected pneumonia. Days of anti-MRSA therapy was significantly reduced in the intervention group (2 [0–3] days vs 1 [0–2] day; P < .01). Time to MRSA de-escalation was also shortened in the intervention group.

Effect of rapid methicillin-resistant Staphylococcus aureus nasal polymerase chain reaction screening on vancomycin use in the intensive care unit

PURPOSE

To determine the impact of a pharmacist-driven methicillin-resistant Staphylococcus aureus (MRSA) nasal polymerase chain reaction (PCR) screen on vancomycin duration in critically ill patients with suspected pneumonia.

METHODS

This was a retrospective, quasi-experimental study at a 613-bed academic medical center with 67 intensive care beds. Adult patients admitted to the intensive care unit (ICU) between 2017 and 2019 for 24 hours or longer and empirically started on intravenous vancomycin for pneumonia were included. The primary intervention was the implementation of a MRSA nasal PCR screen protocol. The primary outcome was duration of empiric vancomycin therapy. Secondary outcomes included the rate of acute kidney injury (AKI), the number of vancomycin levels obtained, the rate of resumption of vancomycin for treatment of pneumonia, ICU length of stay, hospital length of stay, the rate of ICU readmission, and the rate of in-hospital mortality.

RESULTS

A total of 418 patients were included in the final analysis. The median vancomycin duration was 2.59 days in the preprotocol group and 1.44 days in the postprotocol group, a reduction of approximately 1.00 day (P < 0.01). There were significantly fewer vancomycin levels measured in the postprotocol group than in the preprotocol group. Secondary outcomes were similar between the 2 groups, except that there was lower AKI and fewer vancomycin levels obtained in the postprotocol group (despite implementation of area under the curve-based vancomycin dosing) as compared to the preprotocol group.

CONCLUSION

The implementation of a pharmacist-driven MRSA nasal PCR screen was associated with a decrease in vancomycin duration and the number of vancomycin levels obtained in critically ill patients with suspected pneumonia.

Impact of Prior-to-Admission Methicillin-Resistant Staphylococcus aureus Nares Screening in Critically Ill Adults With Pneumonia

BACKGROUND

The high negative predictive value (NPV) of a negative nasal methicillin-resistant Staphylococcus aureus (MRSA) result in suspected MRSA pneumonia is well established; however, data are limited on the NPV of samples collected prior to hospital admission for critically ill patients.

OBJECTIVE

To evaluate the predictive characteristics of MRSA nares screening performed prior to hospital admission in critically ill adult patients diagnosed with pneumonia.

METHODS

A retrospective analysis was conducted in critically ill patients with pneumonia and MRSA nares screening within 60 days of respiratory culture. The primary outcome was NPV of MRSA nares for MRSA pneumonia using samples within 60 days compared to in-hospital respiratory cultures. A sensitivity analysis was performed for samples within 30 days. Secondary outcomes were prevalence, positive predictive value (PPV), sensitivity, specificity, and MRSA pneumonia risk factors.

RESULTS

The NPV for MRSA nares screening collected prior to hospital admission was high at 98% (95% CI = 96%-99%) for samples collected within 60 days (n = 243) and 99% (95% CI: 94%-99.9%) for samples within 30 days (n = 119). Specificity for MRSA nares collected 60 days prior to admission (96%, 95% CI: 93-98) and 30 days (96%, 95% CI: 91%-99%) were both high. PPV and sensitivity were lower. Risk factors for MRSA pneumonia were similar.

CONCLUSION AND RELEVANCE

MRSA nares screening within 60 days of intensive care unit admission has a high NPV and specificity for MRSA pneumonia in critically ill patients and may be a powerful stewardship tool for avoidance of empirical anti-MRSA therapy.

Utility of methicillin-resistant Staphylococcus aureus (MRSA) nasal screening in patients with acute myeloid leukemia (AML)

BACKGROUND

Current literature has demonstrated the utility of the MRSA nasal screen as a de-escalation tool to decrease unnecessary anti-MRSA antibiotic therapy. However, data on the applicability of this test in patients with hematologic malignancy is lacking.

METHODS

This is a single-center, retrospective cohort study of patients with acute myeloid leukemia (AML) with or without a history of hematopoietic cell transplant (HCT), with pneumonia and MRSA nasal screening with respiratory cultures obtained. The primary outcome was to determine the negative predictive value (NPV) of the MRSA nasal screen for MRSA pneumonia. Secondary outcomes included sensitivity, specificity, positive predictive value (PPV) of the MRSA nasal screen and prevalence of MRSA pneumonia.

RESULTS

Of 98 patients with AML and pneumonia, the prevalence of MRSA pneumonia was 4.1% with confirmed positive MRSA respiratory cultures observed in 4 patient cases. In patients with confirmed MRSA pneumonia, 3 had positive MRSA nasal screens while 1 had a false negative result, possibly due to a long lag time (21 days) between MRSA nasal screen and pneumonia diagnosis. Overall, the MRSA nasal screen demonstrated 75% sensitivity and 100% specificity, with a PPV of 100% and a NPV of 98.9%.

CONCLUSIONS

Given the low prevalence, empiric use of anti-MRSA therapy in those AML and HCT patients with pneumonia may not be warranted in clinically stable patients. For patients in whom empiric anti-MRSA antibiotics are initiated, nasal screening for MRSA may be utilized to de-escalate anti-MRSA antibiotics in patients with AML with or without HCT.

Evaluation of the timing of MRSA PCR nasal screening: How long can a negative assay be used to rule out MRSA-positive respiratory cultures?

PURPOSE

Previous studies indicate that the polymerase chain reaction (PCR) nasal assay for methicillin-resistant Staphylococcus aureus (MRSA) has a consistently high (>95%) negative predictive value (NPV) in ruling out MRSA pneumonia; however, optimal timing of PCR assay specimen and respiratory culture collection is unclear.

METHODS

A study including 736 patients from a community hospital system was conducted. Patients were included if they had undergone MRSA nasal screening with a PCR assay and had documented positive respiratory culture results.

RESULTS

In the full cohort, the MRSA PCR nasal screen assay was demonstrated to have an NPV of 94.9% (95% confidence interval [CI], 92.8%-96.5%) in ruling out MRSA-positive respiratory cultures. When evaluating the NPV by level of care (ie, where the MRSA PCR nasal assay sample was collected), no significant difference between values for samples collected in an intensive care unit vs medical/surgical units was identified (NPV [95%CI], 94.9% [92.7%-96.6%] vs 95.3% [88.4%-98.7%]). Additionally, NPV remained high with use of both invasive (NPV [95%CI], 96.8% [92.7%-99.0%]) and noninvasive (NPV [95%CI], 94.5% [91.7%-96.2%]) respiratory sampling methods. Finally, when evaluating the effect of time between MRSA PCR nasal screening and respiratory sample collection, we found high NPVs for all evaluated timeframes: within 24 hours, 93.8% (90.1%-96.4%); within 25 to 48 hours, 98.6% (92.7%-100.0%); within 49 hours to 7 days, 95.7% (91.4%-98.3%); within 8 to 14 days, 92.9% (85.1%-97.3%); and after more than 14 days, 95.5% (84.5%-99.4%).

CONCLUSION

We report high NPVs for up to 2 weeks between specimen collections, which allows clinicians to use a negative MRSA PCR nasal screen assay to rule out MRSA pneumonia, potentially leading to decreased exposure to MRSA-active antibiotics.

Emergency department methicillin-resistant Staphylococcus aureus nare screen effect on pneumonia treatment duration

STUDY OBJECTIVE

The objective of this study was to determine if performing a methicillin-resistant Staphylococcus aureus (MRSA) nasal screen in the emergency department (ED) decreased general medicine patient exposure to anti-MRSA antibiotics for pneumonia.

METHODS

This was a single-center, retrospective study evaluating patients who had a diagnosis of pneumonia and were initiated on anti-MRSA therapy (vancomycin or linezolid) in the ED and subsequently admitted to a general medicine floor. Patients were divided into two groups: 1) did not receive a MRSA nares screen in the ED (No MRSA screen group) or 2) received a MRSA nares screen in the ED (MRSA screen group). The primary outcome was anti-MRSA antibiotic duration. Secondary outcomes included vancomycin level evaluation, hospital survival, and acute kidney injury.

RESULTS

Of the 116 patients included, 37 patients received a MRSA nares screen in the ED and 79 patients did not. Median duration of antibiotic exposure was similar for both groups (No MRSA screen, 30.5 h [interquartile range (IQR) 20.5-52.5] vs. MRSA screen, 24.5 h [IQR 20.6-40.3]; p = 0.28). Of patients who were screened, 35 were negative and 2 were positive. Secondary outcomes were similar.

CONCLUSION

Performing a MRSA nares screen in the ED for patients diagnosed with pneumonia, initiated on anti-MRSA antibiotics, and admitted to a general medicine floor did not decrease duration of anti-MRSA antibiotics. At this time, ED providers do not need to consider a MRSA nasal screen in the ED for patients being admitted to general medicine, although larger studies could be considered.

Risk factors for bacterial infection to cause sensorineural hearing loss in eosinophilic otitis media

OBJECTIVE

Eosinophilic otitis media (EOM) is an intractable type of otitis media in which sensorineural hearing loss (SNHL) progresses over time. Clinically, bacterial infection complicates the course of EOM, making it challenging to control otorrhea/middle ear effusion (MEE) from infected ears, and accelerates the progression of SNHL. In this study, we focused on infection, one of the risk factors for SNHL in EOM, and analyzed factors associated with it.

METHODS

In this cohort study, we evaluated 144 ears of 72 patients diagnosed with bilateral EOM. Patients visited our hospital once every 1-3 months and received intratympanic or systematic administration of steroids when otorrhea/MEE was observed. Several investigations, including blood tests, otorrhea/MEE cytology, bacterial culture tests, and respiratory function tests, were performed. In the otorrhea/MEE cytology, the leukocyte fraction was measured.

RESULTS

Two risk factors for SNHL in EOM were middle ear mucosal thickening (p <0.01) and infection (p <0.05). Compared to the group with <40% neutrophils in otorrhea/MEE samples, groups with 40-70% and ≥70% neutrophils had a significantly higher bone conduction hearing level (p <0.01, p <0.05, respectively). Two risk factors associated with the occurrence of infection in EOM were tympanic membrane (TM) perforation (p <0.01) and the coincidence of otorrhea/MEE and rhinorrhea in bacterial culture test results (p <0.001). A positive correlation was observed between TM perforation and infection (p <0.001). Our analysis of the relationship between the frequency of intratympanic corticosteroids administration and the time-period until the occurrence of TM perforation showed that >4 intratympanic administrations/year significantly increased the risk of perforation (p<0.001). Pseudomonas aeruginosa was isolated from otorrhea/MEE samples, while Pseudomonas aeruginosa and fungi, detected in cultures of rhinorrhea samples, were significantly related to the deterioration of bone conduction hearing levels.

CONCLUSION

The risk factors associated with the occurrence of infection in patients with EOM were TM perforation and the coincidence of otorrhea/MEE and rhinorrhea in bacterial culture test results. Since TM perforation is likely to occur even due to intratympanic corticosteroids administration, it is necessary to confirm whether the frequency of treatment is appropriate and try a less invasive technique of administration. Furthermore, Pseudomonas aeruginosa infection poses a high risk for the development of SNHL, and clinicians should be alert to this possibility, even if the bacteria were identified only in cultures of rhinorrhea samples.

Acute kidney injury following the concurrent administration of antipseudomonal β-lactams and vancomycin: a network meta-analysis

BACKGROUND

Acute kidney injury is a major complication of vancomycin treatment, especially when it is co-administered with other nephrotoxins.

OBJECTIVES

This meta-analysis aims to comparatively assess the nephrotoxicity of antipseudomonal β-lactams when combined with vancomycin.

DATA SOURCES

Medline, Scopus, CENTRAL and Clinicaltrials.gov databases were systematically searched from inception through 20 August 2019.

STUDY ELIGIBILITY CRITERIA

Studies evaluating acute kidney injury risk following the concurrent use of antipseudomonal β-lactams and vancomycin were selected.

PARTICIPANTS

Adult and paediatric patients treated in hospital or intensive care unit.

INTERVENTIONS

Administration of vancomycin combined with any antipseudomonal β-lactam.

METHODS

Acute kidney injury incidence was defined as the primary outcome. Secondary outcomes included severity, onset, duration, need of renal replacement therapy, length of hospitalization and mortality. Quality of evidence was assessed using the ROBINS-I tool and the Confidence In Network Meta-Analysis approach.

RESULTS

Forty-seven cohort studies were included, with a total of 56 984 patients. In the adult population, the combination of piperacillin-tazobactam and vancomycin resulted in significantly higher nephrotoxicity rates than vancomycin monotherapy (odds ratio (OR) 2.05, 95% confidence intervals (CI) 1.17-3.46) and its concurrent use with meropenem (OR 1.84, 95% CI 1.02-3.10) or cefepime (OR 1.80, 95% CI 1.13-2.77). In paediatric patients, acute kidney injury was significantly higher with vancomycin plus piperacillin-tazobactam than vancomycin alone (OR 4.18, 95% CI 1.01-17.29) or vancomycin plus cefepime OR 3.71, 95% CI 1.08-11.24). No significant differences were estimated for the secondary outcomes. Credibility of outcomes was judged as moderate, mainly due to imprecision and inter-study heterogeneity.

CONCLUSIONS

The combination of vancomycin and piperacillin-tazobactam is associated with higher acute kidney injury rates than its parallel use with meropenem or cefepime. Current evidence is exclusively observational and is limited by inter-study heterogeneity. Randomized controlled trials are needed to verify these results and define preventive strategies to minimize nephrotoxicity risk.

Impact of a Pharmacist-Driven MRSA Nasal PCR Protocol on Pneumonia Therapy

Background:Methicillin-resistant Staphylococcus aureus (MRSA) nasal polymerase chain reaction (PCR) testing can rapidly detect MRSA colonization via nasopharyngeal swab. With a high negative predictive value for MRSA pneumonia, this test may help minimize the duration of anti-MRSA therapy and associated adverse drug events. Objective: This study aimed to evaluate the impact of a pharmacist-initiated MRSA nasal PCR protocol on pneumonia therapy. Methods: This retrospective, quasi-experimental study evaluated adult patients with pneumonia before and after the implementation of a pharmacist-initiated MRSA nasal PCR protocol. The primary outcome of this study was to compare duration of anti-MRSA therapy between the Pre-PCR group and PCR group. Secondary comparisons included duration of antipseudomonal therapy, time from intravenous (IV) to oral interchange, and clinical outcomes. Results: In total, 210 patients (Pre-PCR: n = 138, PCR: n = 72) were included. The MRSA nasal PCR result was negative for 63 patients (87.5%), and 56 (88.9%) vancomycin orders were discontinued within 24 hours of the negative result. The mean duration of vancomycin therapy was significantly shorter in the PCR group (2.5 vs 1.4 days, P < .001) as well as duration of IV therapy (5 vs 3.9 days, P = .003). There was no difference between groups in duration of antipseudomonal therapy (P = .425), acute kidney injury (AKI; P = .332), 30-day readmission (P = .137), or 30-day mortality (P = .179). Conclusion and Relevance: A pharmacist-driven MRSA nasal PCR protocol significantly decreased the duration of anti-MRSA therapy and IV antibiotics in patients with pneumonia. These findings add to the relatively small body of literature supporting pharmacist-initiated rapid diagnostic testing and follow-up.

Colonization of the nasal airways by Staphylococcus aureus on admission to a major heart surgery operating room: A real-world experience

INTRODUCTION

Nasal swab culture is used to identify Staphylococcus aureus colonization, as this is a major risk factor for surgical site infection (SSI) in patients who are going to undergo major heart surgery (MHS). We determined nasal carriage of S. aureus in patients undergoing MHS by comparing the yield of a conventional culture with that of a rapid molecular test (Xpert® SA Nasal Complete, Cepheid).

METHODS

From July 2015 to April 2017, all patients who were to undergo MHS were invited to participate in the study. We obtained two nasal cultures from each patient just before entering the operating room, independently of a previous test for the determination of nasal colonization by this microorganism performed before surgery. One swab was used for conventional culture in the microbiology laboratory, and the other was used for the rapid molecular test. We defined nasal colonization as the presence of a positive culture for S. aureus using either of the two techniques. All patients were followed up until hospital discharge or death.

RESULTS

Overall, 57 out of 200 patients (28.5%) were colonized by S. aureus at the time of surgery. Thirty-three patients had both conventional culture- and PCR-positive results. Twenty-four patients had a negative culture and a positive PCR test. Only twenty-one percent (12/57) of colonized patients had undergone an attempt to decolonise before the surgical intervention.

CONCLUSION

A significant proportion of patients undergoing MHS are colonized by S. aureus in the nostrils on entering the operating room. New strategies to prevent SSI by this microorganism are needed. Rapid molecular tests immediately before MHS, followed by immediate decolonisation, must be evaluated. Trial Registration Clinical Trials.gov NCT02640001.

Methicillin-resistant Staphylococcus aureus in solid organ transplantation-Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the American Society of Transplantation Infectious Diseases Community of Practice review the epidemiology, diagnosis, prevention, and management of methicillin-resistant Staphylococcus aureus (MRSA) infections in solid organ transplantation. Despite an increasing armamentarium of antimicrobials active against MRSA, improved diagnostic tools, and overall declining rates of infection, MRSA infections remain a substantial cause of morbidity and mortality in solid organ transplant recipients. Pre- and post-transplant MRSA colonization is a significant risk factor for post-transplant MRSA infection. The preferred initial treatment of MRSA bacteremia remains vancomycin. Hand hygiene, chlorhexidine bathing in the ICU, central-line bundles that focus on reducing unnecessary catheter use, disinfection of patient equipment, and the environment along with antimicrobial stewardship are all aspects of an infection prevention approach to prevent MRSA transmission and decrease healthcare-associated infections.