Distribution and antibiotic susceptibility of pathogens isolated from adults with hospital-acquired and ventilator-associated pneumonia in intensive care unit

Hospital-acquired and ventilator-associated pneumonia caused by multidrug-resistant Gram-negative pathogens: Understanding epidemiology, resistance patterns, and implications with COVID-19

The ongoing spread of antimicrobial resistance has complicated the treatment of bacterial hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP). Gram-negative pathogens, especially those with multidrug-resistant profiles, including Escherichia coli, Klebsiella pneumoniae, Enterobacter spp., Pseudomonas aeruginosa, and Acinetobacter spp., are important culprits in this type of infections. Understanding the determinants of resistance in pathogens causing pneumonia is ultimately stressing, especially in the shadows of the COVID-19 pandemic, when bacterial lung infections are considered a top priority that has become urgent to revise. Globally, the increasing prevalence of these pathogens in respiratory samples represents a significant infection challenge, with major limitations of treatment options and poor clinical outcomes. This review will focus on the epidemiology of HAP and VAP and will present the roles and the antimicrobial resistance patterns of implicated multidrug-resistant (MDR) Gram-negative pathogens like carbapenem-resistant Acinetobacter baumannii (CRAB), carbapenem-resistant Pseudomonas aeruginosa (CRPA), carbapenem-resistant Enterobacterales (CRE), as well as colistin-resistant Gram-negative pathogens and extended-spectrum β-lactamase (ESBL)-producing Enterobacterales. While emerging from the COVID-19 pandemic, perspectives and conclusions are drawn from findings of HAP and VAP caused by MDR Gram-negative bacteria in patients with COVID-19.

Global mapping of antibiotic resistance rates among clinical isolates of Stenotrophomonas maltophilia: a systematic review and meta-analysis

INTRODUCTION

Infections caused by Stenotrophomonas maltophilia are clinically important due to its intrinsic resistance to a broad range of antibiotics. Therefore, selecting the most appropriate antibiotic to treat S. maltophilia infection is a major challenge.

AIM

The current meta-analysis aimed to investigate the global prevalence of antibiotic resistance among S. maltophilia isolates to the develop more effective therapeutic strategies.

METHOD

A systematic literature search was performed using the appropriate search syntax after searching Pubmed, Embase, Web of Science and Scopus databases (May 2023). Statistical analysis was performed using Pooled and the random effects model in R and the metafor package. A total of 11,438 articles were retrieved. After a thorough evaluation, 289 studies were finally eligible for inclusion in this systematic review and meta-analysis.

RESULT

Present analysis indicated that the highest incidences of resistance were associated with doripenem (97%), cefoxitin (96%), imipenem and cefuroxime (95%), ampicillin (94%), ceftriaxone (92%), aztreonam (91%) and meropenem (90%) which resistance to Carbapenems is intrinsic. The lowest resistance rates were documented for minocycline (3%), cefiderocol (4%). The global resistance rate to TMP-SMX remained constant in two periods before and after 2010 (14.4% vs. 14.6%). A significant increase in resistance to tigecycline and ceftolozane/tazobactam was observed before and after 2010.

CONCLUSIONS

Minocycline and cefiderocol can be considered the preferred treatment options due to low resistance rates, although regional differences in resistance rates to other antibiotics should be considered. The low global prevalence of resistance to TMP-SMX as a first-line treatment for S. maltophilia suggests that it remains an effective treatment option.

The small RNA PrrH aggravates Pseudomonas aeruginosa-induced acute lung injury by regulating the type III secretion system activator ExsA

Pseudomonas aeruginosa is an opportunistic pathogen that causes acute and chronic infections in immunocompromised individuals. Small regulatory RNAs (sRNAs) regulate multiple bacterial adaptations to environmental changes, especially virulence. Our previous study showed that sRNA PrrH negatively regulates the expression of a number of virulence factors, such as pyocyanin, rhamnolipid, biofilm, and elastase in the P. aeruginosa strain PAO1. However, previous studies have shown that the prrH-deficient mutant attenuates virulence in an acute murine lung infection model. All ΔprrH-infected mice survived the entire 28-day course of the experiment, whereas all mice inoculated with the wild-type or the complemented mutant succumbed to lung infection within 4 days of injection, but the specific mechanism is unclear. Herein, we explored how PrrH mediates severe lung injury by regulating the expression of virulence factors. In vivo mouse and in vitro cellular assays demonstrated that PrrH enhanced the pathogenicity of PAO1, causing severe lung injury. Mechanistically, PrrH binds to the coding sequence region of the mRNA of exsA, which encodes the type III secretion system master regulatory protein. We further demonstrated that PrrH mediates a severe inflammatory response and exacerbates the apoptosis of A549 cells. Overall, our results revealed that PrrH positively regulates ExsA, enhances the pathogenicity of P. aeruginosa, and causes severe lung injury.

IMPORTANCE

Pseudomonas aeruginosa is a Gram-negative bacterium and the leading cause of nosocomial pneumonia. The pathogenicity of P. aeruginosa is due to the secretion of many virulence factors. Small regulatory RNAs (sRNAs) regulate various bacterial adaptations, especially virulence. Therefore, understanding the mechanism by which sRNAs regulate virulence is necessary for understanding the pathogenicity of P. aeruginosa and the treatment of the related disease. In this study, we demonstrated that PrrH enhances the pathogenicity of P. aeruginosa by binding to the coding sequence regions of the ExsA, the master regulatory protein of type III secretion system, causing severe lung injury and exacerbating the inflammatory response and apoptosis. These findings revealed that PrrH is a crucial molecule that positively regulates ExsA. Type III-positive strains are often associated with a high mortality rate in P. aeruginosa infections in clinical practice. Therefore, this discovery may provide a new target for treating P. aeruginosa infections, especially type III-positive strains.

In vitro evaluation of biofilm phenotypic and genotypic characteristics among clinical isolates of Pseudomonas aeruginosa in Hamadan, West of Iran

Due to high antimicrobial resistance and biofilm-forming ability, Pseudomonas aeruginosa is one of the seriously life-threatening agents causing chronic and nosocomial infections. This study was performed to determine the antibiotic resistance pattern, biofilm formation, and frequency of biofilm-related genes in P. aeruginosa strains. In total, 123 P. aeruginosa isolates were collected from different clinical sources. Antimicrobial susceptibility testing (AST) was performed to detect multidrug-resistant P. aeruginosa (MDRPA) isolates. To evaluate the biofilm-forming isolates, the microtiter plate (MTP) method was carried out. Also, the prevalence of biofilm genotype patterns, including pslA, pslD, pelA, pelF, and algD genes, was detected by polymerases chain reaction (PCR). According to our findings, the highest resistance and susceptibility rates were found in ceftazidime with 74.7% (n = 92) and ciprofloxacin with 42.2% (n = 52), respectively. In our study, the highest level of antibiotic resistance belonged to wound isolates which meropenem had the most antibacterial activity against them. In total, 86.1% (n = 106) P. aeruginosa isolates were determined as MDRPA, of which 61.3% (n = 65) were able to form strong biofilm. The highest and lowest frequency of biofilm-related genes among biofilm producer isolates belonged to pelF with 82.1% (n = 101) and algD with 55.2% (n = 68), respectively. The findings of the conducted study indicate a significant relationship between MDRPA and biofilm genotypic/phenotypic patterns, suggesting the necessity of a careful surveillance program in hospital settings.

Comparison of Cefepime with Piperacillin/Tazobactam Treatment in Patients with Hospital-Acquired Pneumonia

Although cefepime and piperacillin/tazobactam are commonly prescribed for the treatment of hospital-acquired pneumonia (HAP), which one is the superior therapy remains unclear. Using Korean National Health Insurance Service data from January 2018 to December 2018, we compared the clinical outcomes of patients with HAP who were treated with cefepime and those treated with piperacillin/tazobactam. Data from 9955 adult patients with HAP, of whom 1502 (15%) received cefepime and 8453 (85%) received piperacillin/tazobactam, were retrieved for primary analysis. Tube feeding, suctioning, positioning care, and intensive care unit admission were more common among patients who received piperacillin/tazobactam. Treatment outcomes, including rates of in-hospital mortality, pneumonia-related readmission, and all-cause mortality within 6 months after discharge, were comparable between the two groups. In a subgroup analysis of data from patients who required tube feeding, the risk for in-hospital mortality was significantly higher among those who received cefepime (fully adjusted odds ratio, 1.43; 95% confidence interval, 1.04-1.97; p = 0.042). Treatment outcomes did not differ between patients who received cefepime and those who received piperacillin/tazobactam treatment, but among patients who were at risk for aspiration, such as those receiving tube feeding, those who received piperacillin/tazobactam had lower rates of in-hospital mortality.

Burden of severe infections due to carbapenem-resistant pathogens in intensive care unit

Intensive care units (ICU) for various reasons, including the increasing age of admitted patients, comorbidities, and increasingly complex surgical procedures (e.g., transplants), have become "the epicenter" of nosocomial infections, these are characterized by the presence of multidrug-resistant organisms (MDROs) as the cause of infection. Therefore, the perfect match of fragile patients and MDROs, as the cause of infection, makes ICU mortality very high. Furthermore, carbapenems were considered for years as last-resort antibiotics for the treatment of infections caused by MDROs; unfortunately, nowadays carbapenem resistance, mainly among Gram-negative pathogens, is a matter of the highest concern for worldwide public health. This comprehensive review aims to outline the problem from the intensivist's perspective, focusing on the new definition and epidemiology of the most common carbapenem-resistant MDROs (Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacterales) to emphasize the importance of the problem that must be permeating clinicians dealing with these diseases.

Global prevalence and antibiotic resistance in clinical isolates of Stenotrophomonas maltophilia: a systematic review and meta-analysis

Introduction

Stenotrophomonas maltophilia is a little-known environmental opportunistic bacterium that can cause broad-spectrum infections. Despite the importance of this bacterium as an emerging drug-resistant opportunistic pathogen, a comprehensive analysis of its prevalence and resistance to antibiotics has not yet been conducted.

Methods

A systematic search was performed using four electronic databases (MEDLINE via PubMed, Embase, Scopus, and Web of Science) up to October 2019. Out of 6,770 records, 179 were documented in the current meta-analysis according to our inclusion and exclusion criteria, and 95 studies were enrolled in the meta-analysis.

Results

Present analysis revealed that the global pooled prevalence of S. maltophilia was 5.3 % [95% CI, 4.1-6.7%], with a higher prevalence in the Western Pacific Region [10.5%; 95% CI, 5.7-18.6%] and a lower prevalence in the American regions [4.3%; 95% CI, 3.2-5.7%]. Based on our meta-analysis, the highest antibiotic resistance rate was against cefuroxime [99.1%; 95% CI, 97.3-99.7%], while the lowest resistance was correlated with minocycline [4·8%; 95% CI, 2.6-8.8%].

Discussion

The results of this study indicated that the prevalence of S. maltophilia infections has been increasing over time. A comparison of the antibiotic resistance of S. maltophilia before and after 2010 suggested there was an increasing trend in the resistance to some antibiotics, such as tigecycline and ticarcillin-clavulanic acid. However, trimethoprim-sulfamethoxazole is still considered an effective antibiotic for treating S. maltophilia infections.

Carbapenem-Resistant Gram-Negative Bacilli Causing Ventilator Associated Pneumonia: Study of MASTDISCS Combi Carba Plus for Detection of Carbapenemase Producing Enterobacterales

Background

Ventilator-associated pneumonia (VAP) caused by carbapenem-resistant gram-negative bacteria has been proven to be an escalating public health challenge in Egypt owing to its high mortality rate and raised health care costs.

Purpose

Detection of carbapenem-resistant gram-negative bacilli among VAP patients, genotypic identification of carbapenemase genes in the isolated strains with evaluation of their impact on patient outcome and detection of carbapenemase-producing enterobacterales by MASTDISCS combi Carba plus disc system.

Methods

Broncho-alveolar lavage fluid (BALF) and endotracheal aspirate were collected aseptically from clinically suspected VAP patients. Pathogen identification and antibiotic sensitivity testing were done. Carbapenemase-encoding genes (bla_KPC, bla_NDM, and bla_OXA-48) were tested by PCR in all carbapenem-resistant gram-negative isolates. Performance of MASTDISCS combi Carba plus in isolated Enterobacterales was assessed in relation to the PCR results.

Results

Eighty-three carbapenem-resistant gram-negative isolates were detected. The most frequent pathogens were Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa representing 34.9%, 20.5% and 18.1%, respectively. bla_KPC was the predominant gene. Patients with persistent mechanical ventilation less than 15 days and Pseudomonas aeruginosa infection were significantly associated with a higher death rate. MAST-Carba plus had the highest sensitivity, specificity, positive and negative predictive values for detecting OXA-48 carbapenemases representing 81.8%, 92.5%, 75% and 94.9%, respectively.

Conclusion

Worse outcome in VAP patients was associated with carbapenem-resistant gram-negative bacilli. MASTDISCS combi Carba plus is an efficient simple method for identification of different carbapenemases among enterobacterales.

The Use of Antibiotics for Ventilator-Associated Pneumonia in the MIMIC-IV Database

Purpose: By analyzing the clinical characteristics, etiological characteristics and commonly used antibiotics of patients with ventilator-associated pneumonia (VAP) in intensive care units (ICUs) in the intensive care database. This study aims to provide guidance information for the clinical rational use of drugs for patients with VAP.

Method: Patients with VAP information were collected from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database, including their sociodemographic characteristics, vital signs, laboratory measurements, complications, microbiology, and antibiotic use. After data processing, the characteristics of the medications used by patients with VAP in ICUs were described using statistical graphs and tables, and experiences were summarized and the reasons were analyzed.

Results: This study included 2,068 patients with VAP. Forty-eight patient characteristics, including demographic indicators, vital signs, biochemical indicators, scores, and comorbidities, were compared between the survival and death groups of VAP patients. Cephalosporins and vancomycin were the most commonly used. Among them, fourth-generation cephalosporin (ForGC) combined with vancomycin was used the most, by 540 patients. First-generati49n cephalosporin (FirGC) combined with vancomycin was associated with the highest survival rate (86.7%). More than 55% of patients were infected with Gram-negative bacteria. However, patients with VAP had fewer resistant strains (<25%). FirGC or ForGC combined with vancomycin had many inflammation-related features that differed significantly from those in patients who did not receive medication.

Conclusion: Understanding antibiotic use, pathogenic bacteria compositions, and the drug resistance rates of patients with VAP can help prevent the occurrence of diseases, contain infections as soon as possible, and promote the recovery of patients.

Multiplex detection of five common respiratory pathogens from bronchoalveolar lavages using high resolution melting curve analysis

Background

The study describes the application of the multiplex high-resolution melting curve (MHRM) assay for the simultaneous detection of five common bacterial pathogens (Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii and Escherichia coli) directly from bronchoalveolar lavage samples.

Results

Our MHRM assay successfully identified all five respiratory pathogens in less than 5 h, with five separate melting curves with specific melt peak temperatures (Tm). The different Tm were characterized by peaks of 78.1 ± 0.4 °C for S. aureus, 83.3 ± 0.1 °C for A. baumannii, 86.7 ± 0.2 °C for E. coli, 90.5 ± 0.1 °C for K. pneumoniae, 94.5 ± 0.2 °C for P. aeruginosa. The overall sensitivity and specificity of MHRM were 100% and 88.8–100%, respectively.

Conclusions

Our MHRM assay offers a simple and fast alternative to culture approach for simultaneous detection of five major bacterial lower respiratory tract infection pathogens. Utilization of this assay can help clinicians initiate prompt and appropriate antimicrobial treatment, towards reducing the morbidity and mortality of severe respiratory infections.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-022-02558-2.

Antibiotic resistance, biofilm production ability and genetic diversity of carbapenem-resistant Pseudomonas aeruginosa strains isolated from nosocomial infections in southwestern Iran

Background

This study was aimed to evaluate the antibiotic resistance, biofilm formation, and genetic diversity of carbapenem-resistant Pseudomonas aeruginosa (CRPA) strains isolated from four types of nosocomial infections (NIs) including urinary tract infection (UTI), ventilator-associated pneumonia (VAP), surgical site infection (SSI), and bloodstream infection (BSI).

Methods and results

In total, 115 isolates of NIs-causing P. aeruginosa were collected from NIs. Antibiotic susceptibility testing (AST) was performed using disk diffusion method and minimum inhibitory concentrations. Biofilm formation was tested on 96-well polystyrene microtiter plates (MTP). CRPA isolates were genotyped using multiple-locus variable number of tandem repeat analysis (MLVA). The most resistance and susceptibility rates were observed to amikacin (70.6%) and colistin (96.1%), respectively. Colistin and meropenem were the most active antimicrobial agents in VAP, SSI, and BSI. While, colistin and cefepime were the most active in UTIs. In total, 52.2% (n = 60/115) of P. aeruginosa isolates were carbapenem resistant, of which 95.0%, 55.0%, and 5.0% were multidrug-resistant, extensively drug-resistant, and pandrug-resistant, respectively. There was a significant association between resistance to carbapenem and resistance to other antibiotics except for piperacillin/tazobactam. The biofilm production of CRPA isolates was 95.0%, of which 23.3% were strong biofilm producers. Based on MLVA, there were 34 different types of CRPA isolates classified into three main clusters and 5 sub clusters.

Conclusion

The association of CRPA with other antibiotic resistance, the high rates of biofilm production, and the high genetic diversity of the isolates may be a warning of the need for a careful surveillance program.

Identification and detection of pathogenic bacteria from patients with hospital-acquired pneumonia in southwestern Iran; evaluation of biofilm production and molecular typing of bacterial isolates

Background

Hospital-acquired pneumonia (HAP) is the second most common nosocomial infection in intensive care units (ICUs). The present study aims to determine the prevalence of pathogenic bacteria, their biofilm formation, and molecular typing from patients with HAP in southwestern Iran.

Methods

Fifty-eight patients with HAP participated in this cross-sectional study. Sputum and endotracheal aspirate were collected from each patient for isolation and detection of bacteria. Biofilm formation was evaluated using Congo red agar or Microtiter plate assay. The antimicrobial susceptibility patterns of the isolates were investigated. The multiplex polymerase chain reaction (M-PCR) technique was used to determine the Staphylococcal Cassette Chromosome mec (SCCmec) types of methicillin-resistant Staphylococcus aureus (MRSA) strains. All S. aureus isolates were typed using the agr typing method. A repetitive element sequence-based PCR (rep-PCR) typing method was used for typing of Gram-negative bacteria. Data were analyzed using the Statistical Package for the Social Sciences (SPSS) software version 15 and the chi-square test.

Results

Bacteria were isolated in 52 (89.7%) of patients. Acinetobacter baumannii (A. baumannii) was the most prevalent organism (37%), followed by S. aureus, Pseudomonas aeruginosa (P. aeruginosa), and Escherichia coli (E. coli). Using the PCR method, 56 bacteria were detected. A. baumannii was the most prevalent (35.7%) organism. A. baumannii and P. aeruginosa were biofilm-producing. All Gram-negative isolates were colistin-sensitive, and most of the A. baumannii isolates were multidrug-resistant (MDR). MRSA was identified in 12 (80%) S. aureus isolates, and 91.6% of MRSA were SCCmec type III. The agr type III was the most predominant. The rep-PCR analysis showed seven different patterns in 20 A. baumannii, six patterns in 13 P. aeruginosa, and four patterns in 6 E. coli.

Conclusion

A. baumannii was more prevalent than S. aureus in ventilator-associated pneumonia (VAP), while S. aureus is a major pathogen in non-ventilator hospital-acquired pneumonia (NV-HAP), possibly due to the tendency of the former to aquatic environments. Based on the rep-PCR typing method, it was concluded that bacteria were transmitted from patients or healthcare workers among different wards. Colistin can be used as a treatment in Gram-negative MDR isolates.

The Impact of COVID-19 on the Profile of Hospital-Acquired Infections in Adult Intensive Care Units

Hospital-acquired infections (HAIs) are a global public health concern. As the COVID-19 pandemic continues, its contribution to mortality and antimicrobial resistance (AMR) grows, particularly in intensive care units (ICUs). A two-year retrospective study from April 2019-April 2021 was conducted in an adult ICU at the Hospital for Infectious and Tropical Diseases, Belgrade, Serbia to assess causative agents of HAIs and AMR rates, with the COVID-19 pandemic ensuing halfway through the study. Resistance rates >80% were observed for the majority of tested antimicrobials. In COVID-19 patients, Acinetobacter spp. was the dominant cause of HAIs and more frequently isolated than in non-COVID-19 patients. (67 vs. 18, p = 0.001). Also, resistance was higher for imipenem (56.8% vs. 24.5%, p < 0.001), meropenem (61.1% vs. 24.3%, p < 0.001) and ciprofloxacin (59.5% vs. 36.9%, p = 0.04). AMR rates were aggregated with findings from our previous study to identify resistance trends and establish empiric treatment recommendations. The increased presence of Acinetobacter spp. and a positive trend in Klebsiella spp. resistance to fluoroquinolones (R² = 0.980, p = 0.01) and carbapenems (R² = 0.963, p = 0.02) could have contributed to alarming resistance rates across bloodstream infections (BSIs), pneumonia (PN), and urinary tract infections (UTIs). Exceptions were vancomycin (16.0%) and linezolid (2.6%) in BSIs; tigecycline (14.3%) and colistin (0%) in PNs; and colistin (12.0%) and linezolid (0%) in UTIs. COVID-19 has changed the landscape of HAIs in our ICUs. Approval of new drugs and rigorous surveillance is urgently needed.

Hospital-acquired infections in the adult intensive care unit-Epidemiology, antimicrobial resistance patterns, and risk factors for acquisition and mortality

BACKGROUND

Acquisition of Hospital-acquired infections (HAIs) in intensive care units (ICUs) predispose patients to higher mortality rates and additional adverse events. Serbian adult ICUs are rarely investigated for HAIs. The aim of this study was to look into HAIs in an adult ICU and identify risk factors for acquisition of HAIs and mortality.

METHODS

This retrospective study included 355 patients hospitalized over a 2-year period. Patient characteristics, antimicrobial resistance patterns, and risk factors of acquisition and predictors of mortality in patients who had a HAI were examined.

RESULTS

HAIs were diagnosed in 32.7% of patients. Resistance rates > 50% were observed in all antimicrobials except for tigecycline (14%), colistin (9%), and linezolid (0%). Predictors of HAI acquisition were underlying viral CNS infections and invasive devices-urinary and central venous catheters, and nasogastric tubes. Diabetes mellitus and intubation (odds ratio 2.5 and 6.7, P = .042 and <.001) were identified as predictors for increased mortality in patients who had a HAI.

CONCLUSIONS

Prevalence of HAIs and resistance rates are high compared to ICUs in other European countries. Risk factors for both acquisition of HAI and mortality were identified. Large-scale studies are necessary to look at HAIs in adult ICUs in Serbia.

Is ventilated hospital-acquired pneumonia a worse entity than ventilator-associated pneumonia?

Introduction

Nosocomial pneumonia develops after ≥48 h of hospitalisation and is classified as ventilator-associated pneumonia (VAP) and hospital-acquired pneumonia (HAP); the latter may require mechanical ventilation (V-HAP) or not (NV-HAP).

Main findings

VAP and HAP affect a significant proportion of hospitalised patients and are characterised by poor clinical outcomes. Among them, V-HAP has the greatest 28-day mortality rate followed by VAP and NV-HAP (27.8% versus 18% versus 14.5%, respectively). However, no differences in terms of pathophysiology, underlying microbiological pathways and subsequent therapy have been identified. International guidelines suggest specific flow charts to help clinicians in the therapeutic management of such diseases; however, there are no specific recommendations beyond VAP and HAP classification. HAP subtypes are scarcely considered as different entities and the lack of data from the clinical scenario limits any final conclusion. Hopefully, recent understanding of the pathophysiology of such diseases, as well as the discovery of new therapies, will improve the outcome associated with such pulmonary infections.

Conclusion

Nosocomial pneumonia is a multifaced disease with features of pivotal interest in critical care medicine. Due to the worrisome data on mortality of patients with nosocomial pneumonia, further prospective studies focused on this topic are urgently needed.

Due to the different mortality of each subtype of nosocomial pneumonia, including ventilator-associated pneumonia and hospital-acquired pneumonia requiring mechanical ventilation, new prospective studies are urgently neededhttps://bit.ly/3fFoZ6U

Contributing Factors to the Clinical and Economic Burden of Patients with Laboratory-Confirmed Carbapenem-Nonsusceptible Gram-Negative Respiratory Infections

PURPOSE

This study examined patient- and hospital-level predictor variables that contribute to worse clinical and economic outcomes in patients with carbapenem-nonsusceptible respiratory infections.

PATIENTS AND METHODS

Electronic data (January 2013 to September 2015) were from 78 US hospitals. Nonduplicate, gram-negative respiratory isolates were considered carbapenem-nonsusceptible if they tested resistant/intermediate to imipenem, meropenem, doripenem, or ertapenem. Potential predictors of outcomes (in-hospital mortality, 30-day readmission, length of stay [LOS], hospital total cost, and net gain/loss per patient) were examined using univariate analysis and generalized linear mixed models. Statistical significance and model goodness-of-fit criteria were used to identify significant predictors.

RESULTS

A total of 1488 carbapenem-nonsusceptible respiratory patients were identified. Overall, the mortality rate was 13.7%, 30-day readmission rate was 20.6%, mean LOS was 20 days, mean total cost was $54,158, and mean net loss was $139 per patient. Our models showed that hospital-onset infection, higher clinical severity, mechanical ventilation/intensive care unit status, polymicrobial infection, and underlying diseases were all significant predictors for mortality, LOS, and total cost. Hospital-onset infections were also associated with a significantly greater net loss (P≤.01), and underlying disease significantly impacted readmissions (P=.03). The number of prior admissions, hospital characteristics, and payer type were also found to significantly impact measured outcomes.

CONCLUSION

Carbapenem-nonsusceptible respiratory infections are associated with a considerable clinical and economic burden. The impact of hospital-onset infections on both clinical and economic outcomes highlights the continued need for action on this modifiable risk factor through antimicrobial stewardship and optimal therapy, thereby reducing the burden in this patient population.

Attributable burden in patients with carbapenem-nonsusceptible gram-negative respiratory infections

Objective

We aimed to describe the clinical and economic burden attributable to carbapenem-nonsusceptible (C-NS) respiratory infections.

Methods

This retrospective matched cohort study assessed clinical and economic outcomes of adult patients (aged ≥18 years) who were admitted to one of 78 acute care hospitals in the United States with nonduplicate C-NS and carbapenem-susceptible (C-S) isolates from a respiratory source. A subset analysis of patients with principal diagnosis codes denoting bacterial pneumonia or other diagnoses was also conducted. Isolates were classified as community- or hospital-onset based on collection time. A generalized linear mixed model method was used to estimate the attributable burden for mortality, 30-day readmission, length of stay (LOS), cost, and net gain/loss (payment minus cost) using propensity score-matched C-NS versus C-S cohorts.

Results

For C-NS cases, mortality (25.7%), LOS (29.4 days), and costs ($81,574) were highest in the other principal diagnosis, hospital-onset subgroup; readmissions (19.4%) and net loss (-$9522) were greatest in the bacterial pneumonia, hospital-onset subgroup. Mortality and readmissions were not significantly higher for C-NS cases in any propensity score-matched subgroup. Significant C-NS–attributable burden was found for both other principal diagnosis subgroups for LOS (hospital-onset: 3.7 days, P = 0.006; community-onset: 1.5 days, P<0.001) and cost (hospital-onset: $12,777, P<0.01; community-onset: $2681, P<0.001).

Conclusions

Increased LOS and cost burden were observed in propensity score-matched patients with C-NS compared with C-S respiratory infections; the C-NS–attributable burden was significant only for patients with other principal diagnoses.

Differences in microbial etiology between hospital-acquired pneumonia and ventilator-associated pneumonia: a single-center retrospective study in Guang Zhou

Purpose: Nosocomial pneumonia is a common nosocomial infection that includes hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia(VAP). It is an important cause of morbidity and mortality in hospitalized patients. This study aimed to evaluate the differences in microbial etiology and outcomes between HAP and VAP, particularly in related risk factors of multidrug-resistant organism (MDRO) causing HAP and VAP.

Patients and methods: This single-center retrospective, observational study included patients with HAP/VAP. Clinical and epidemiological data of nosocomial pneumonia confirmed by microbial etiology that occurred in the Third Affiliated Hospital of Sun Yat-sen University, China, from January 2014 to December 2017 were obtained.

Results: A total of 313 HAP cases and 106 VAP cases were included. The leading pathogens of HAP and VAP were similar, including Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Antimicrobial susceptibility of the pathogens was low, and P. aeruginosa in VAP was less susceptible. In the multivariate logistic regression analysis, the risk factors associated with MDRO-HAP were chronic obstructive pulmonary disease, antibiotic therapy in the preceding 90 days, and prior endotracheal tracheostomy. The risk factor of MDRO-VAP was ≥5 days of hospitalization. The 30-day mortality rates of HAP and VAP were 18.5% and 42.5%.

Conclusion: The leading pathogens were similar in both HAP and VAP, and antimicrobial susceptibility of the pathogens was low. The risk factors associated with MDRO infection in HAP and VAP have significant variability; hence, attention should be paid to improve prognosis. VAP was associated with poorer outcomes compared with HAP.

Description of Clinical Characteristics of VAP Patients in MIMIC Database

Background: Ventilator-associated pneumonia (VAP) is a common and serious nosocomial infection of intensive-care units (ICUs). Accurate, timely diagnosis enables early VAP patients to receive appropriate therapies and reduce the occurrence of complication. However, so far clinical datas regarding the epidemiology and mortality of VAP are still limited. Medical Information Mart for Intensive Care (MIMIC) database is a free, open and public resource about ICU research database. MIMIC database is a free, open, public database that collects information on more than 40,000 ICU patients who are predominantly white people. Therefore, the purpose of the present study is to observe and describe the clinical characteristics of VAP patients in ICU from the MIMIC database.

Method: A total of 418 patients were enrolled in the study. General information, ventilator use information, microbiology information, antibiotic use information, and some nursing-related information were extracted to describe and analyze the clinical features of VAP patients.

Results: The results of the study showed that patients with one or three pathogens were the most. The main pathogens were YEAST (16.71%), STAPH AUREUS COAG+ (11.63%), Staphylococcus, COAGULASE NEGATIVE (8.68%), GRAM NEGATIVE ROD (S) (6.14%), and Pseudomonas aeruginosa (5.73%). Patients using 4 antibiotics were the most. The top five antibiotics in the largest proportion were synthetic antibacterials (24.66%), peptides (20.13%), cephalosporins (19.60%), penicillins (13.54%), and aminoglycosides (5.27%).

Conclusion: This study summarizes the common pathogens of VAP and the antibiotics commonly used in the treatment of VAP by describing the clinical information of 418 patients with VAP in the MIMIC database. In clinical treatment, we should pay attention to aseptic operation, develop appropriate antibacterial measures, closely monitor the pathogens of VAP infection, and use antibiotics in a timely manner to control the occurrence and development of VAP.

Soluble CD14 Subtype-A New Biomarker in Predicting the Outcome of Critically Ill Septic Patients

BACKGROUND

We evaluated the role of presepsin (soluble CD14 subtype, sCD14-ST) in predicting the outcome of critically ill septic patients in parallel with procalcitonin and C-reactive protein.

METHODS

This study was an observational, prospective study that enrolled 58 surgical and medical intensive care unit patients with suspected sepsis. All studied subjects were retrospectively stratified into survivors and nonsurvivors based on 28 days survival and according to microbiological results in blood culture positive and negative groups. Plasma and serum samples from each patient were collected at admission (T-0), after 24-48 hours (T-1) and after 7 days (T-2). Statistics were obtained using Student׳s t test and ANOVA, as well as Bonferroni post hoc test. Receiver-operating characteristic (ROC) analysis was also performed.

RESULTS

Presepsin levels were significantly higher at T-0 (P = 0.0007), at T-1 (P < 0.0001) and at T-2 (P < 0.0001) in nonsurvivors versus survivors at the same time point. Presepsin concentrations were significantly increased at T-0 (P = 0.0073), T1 (P = 0.0111) and T2 (P = 0.0167) in patients with positive blood cultures in comparison to patients with negative cultures at the same time. For all time periods evaluated, presepsin data from nonsurviving and surviving individuals were subjected to ROC analysis that demonstrated an excellent accuracy and significant area under the ROC curve (P < 0.0001). Results of multivariate analysis indicated presepsin as a predictive independent variable among prognosis markers at T-0 (P = 0.016).

CONCLUSIONS

Presepsin revealed an optimal prognostic performance in patients with severe sepsis and provided interesting diagnostic value. Prediction of outcome in critically ill patients is crucial to optimize management decisions and level of treatment.