The Distribution of Multidrug-resistant Microorganisms and Treatment Status of Hospital-acquired Pneumonia/Ventilator-associated Pneumonia in Adult Intensive Care Units: a Prospective Cohort Observational Study

External validation and application of risk prediction model for ventilator-associated pneumonia in ICU patients with mechanical ventilation: A prospective cohort study

BACKGROUND

Early identification and prevention of ventilator-associated pneumonia (VAP) in patients with mechanical ventilation (MV) through reliable prediction model undergoing a rigorous and standardized process is essential for clinical decision-making.

OBJECTIVE

This study aims to externally validate the VAP prediction model previously developed by a tertiary hospital in Northwestern China, using data from different time periods or hospitals, and to develop a web-based model calculator for clinical application to evaluate the model's prediction performance and generalizability.

METHODS

We prospectively collected MV patients data from the ICUs of two tertiary hospitals in Northwestern China for external validation of the model. Temporal and geographical validation were performed at the hospital where the model was developed and another hospital, respectively. The area under the receiver operating characteristic curve (AUC), Howsmer-Lemeshow test, calibration curve and decision curve analysis (DCA) were used to evaluate the model's discrimination, calibration and clinical applicability, respectively. A web-based model calculator was further developed and applied to MV patients in one of the hospitals to obtain the prediction probabilities of VAP risk. Model performance was evaluated using a confusion matrix and diagnostic tests.

RESULTS

The temporal and geographical validation cohorts included 416 and 410 patients, and the AUCs were 0.814 and 0.800, respectively. The Hosmer-Lemeshow tests (both P > 0.05) and calibration curves showed a relatively high consistency. The DCA revealed the model threshold probabilities in the temporal (2.0 % to 50.0 %) and geographical validation (5.0 % to 70.0 %). The web-based model calculator (https://vapnomogram.shinyapps.io/VAPDynNomapp/) was applied to 202 patients in clinical practice. The cut-off value of the prediction probability was 0.096, with an accuracy of 0.911, a sensitivity of 0.900, a specificity of 0.912, and a positive and negative predictive value of 0.529 and 0.988, respectively.

CONCLUSION

The VAP prediction model showed relatively stable and relaible clinical prediction performance and generalizability, with a clinical application and promotion value.

Bacterial Superinfections After SARS-CoV-2 Pneumonia: Antimicrobial Resistance Patterns, Impact on Inflammatory Profiles, Severity Scores, and Clinical Outcomes

Background and Objectives: Secondary bacterial pneumonia can substantially worsen the clinical trajectory of patients hospitalized for Coronavirus Disease 2019 (COVID-19). This study aimed to characterize bacterial superinfections in COVID-19, including pathogen profiles, resistance patterns, inflammatory responses, severity scores, and ICU admission risk. Methods: In a retrospective cohort design, we reviewed 141 patients admitted to a single tertiary-care hospital between February 2021 and December 2024. A total of 58 patients had laboratory-confirmed bacterial superinfection by sputum, bronchoalveolar lavage, or blood cultures (superinfection group), whereas 83 had COVID-19 without any documented bacterial pathogens (COVID-only group). We collected detailed microbiological data from sputum, bronchoalveolar lavage (BAL), and blood cultures. Antibiotic sensitivity testing was performed using standard breakpoints for multidrug resistance (MDR). Inflammatory markers (C-reactive protein, procalcitonin, neutrophil-to-lymphocyte ratio, and systemic immune-inflammation index) and the severity indices Acute Physiology and Chronic Health Evaluation (APACHE) II, Confusion, Urea, Respiratory rate, Blood pressure (CURB), and National Early Warning Score (NEWS) were measured at admission. Primary outcomes included intensive care unit (ICU) admission, mechanical ventilation, and mortality. Results: Patients in the superinfection group showed significantly elevated inflammatory markers and severity scores compared to the COVID-only group (mean APACHE II of 17.2 vs. 13.8; p < 0.001). Pathogens most frequently isolated from sputum and BAL included Klebsiella pneumoniae (27.6%) and Pseudomonas aeruginosa (20.7%). Multidrug-resistant strains were documented in 32.8% of isolates. The superinfection group had higher ICU admissions (37.9% vs. 19.3%; p = 0.01) and more frequent mechanical ventilation (25.9% vs. 9.6%; p = 0.01). Mortality trended higher among superinfected patients (15.5% vs. 7.2%; p = 0.09). A total of 34% of the cohort had prior antibiotic use, which independently predicted MDR (aOR 2.6, p = 0.01). The presence of MDR pathogens such as Klebsiella pneumoniae (OR 2.8), Pseudomonas aeruginosa (OR 2.5), and Staphylococcus aureus (OR 2.1) significantly increases the risk of ICU admission. Conclusions: Bacterial superinfection exacerbates inflammation and worsens outcomes in COVID-19 patients, such as a higher risk of ICU admission.

Distribution characteristics of aerosol microorganisms in bronchoscopy room and the risk assessment of nosocomial infection

Objective

A large number of aerosols containing pathogenic microorganisms can be produced during bronchoscopy. The aim of the study is to evaluate the risk of nosocomial infection by pathogenic microorganisms after bronchoscopy. The distribution characteristics of aerosol microorganisms were detected before and after bronchoscopy, and then compared with the distribution characteristics of the patients' respiratory pathogens.

Methods

A total of 152 patients underwent bronchoscopy in the bronchoscopy room from May 06, 2024 to June 30, 2024. Airborne microorganisms were collected in the bronchoscopy room before and after the bronchoscopy, then cultured, counted and identified, to analyze the species, numbers and changes of microorganisms. At the same time, the data of respiratory pathogens and nosocomial infection of all patients were collected to evaluate the correlation between air microorganisms and respiratory pathogens, and the risk of nosocomial infection.

Results

(1) The concentration of air microorganisms after bronchoscopy was 89.60 ± 63.52 CFU/m3, significantly higher than 43.80 ± 26.70 CFU/m3 before bronchoscopy (p < 0.001). The increase in air microorganism concentration was in accordance with the total number of patients and the number of patients with respiratory infectious diseases on the same day (p < 0.001). After bronchoscopy for patients with infectious diseases, the concentration was significantly higher than that for patients with non-infectious diseases (p < 0.05). (2) The bacteria accounted for 75.34, 70.35% of the total aerosol microorganisms, fungi 22.17, 26.80% before and after bronchoscopy. The bacteria mainly included Micrococcus luteus, Staphylococcus epidermidis, Staphylococcus hominis, Haemophilus influenzae, Neisseria faunalis, Staphylococcus capitis, etc. The fungi mainly included Aspergillus flavus, Aspergillus niger, Saccharomyces albicans, Penicillium spp., etc. (3) The increase in air microorganisms after bronchoscopy was consistent with the distribution of pathogens causing respiratory infections in patients (p < 0.001). The increased pathogens were mainly composed of common respiratory pathogens, but it did not increase the risk of nosocomial respiratory infections in patients (p = 0.735).

Conclusion

Bronchoscopy can increase the concentration of aerosol microorganisms. The increased microorganisms are related to the respiratory pathogens of patients, which are mainly the common pathogens of pulmonary infection. This, however, does not increase the risk of nosocomial respiratory infection.

Independent risk factors and outcomes for ventilator-associated pneumonia due to multidrug-resistant organisms after cardiac valvular surgery

Background

Although numerous studies have documented the risk factors for ventilator-associated pneumonia (VAP) after cardiac surgery, most of these studies included heterogeneous patient populations. This study aimed to explore the risk factors for VAP caused by multidrug-resistant organisms (MDRO) in patients admitted to the cardiosurgery intensive care unit (CSICU) following cardiac valvular surgery.

Methods

This was a single-center, retrospective study. The clinical data of adult VAP patients following cardiac valvular surgery from January 2021 to December 2023 were analyzed. Patients were divided into MDRO VAP and non-MDRO VAP groups. Perioperative clinical data and postoperative follow-up results were collected for both groups. Univariable and multivariable logistic regression analyses were performed to identify risk factors for MDRO VAP, and the outcomes of MDRO VAP patients were analyzed. The species of pathogens isolated from the VAP patients were also investigated.

Results

A total of 109 VAP patients were included in this study, including 47 patients with MDRO VAP and 62 patients with non-MDRO VAP. Multivariable logistic regression analysis identified that independent risk factors for MDRO VAP included preoperative hypoalbuminemia (OR, 0.838; CI, 0.733-0.957; p = 0.009), prolonged mechanical ventilation (OR, 1.173; CI, 1.005-1.369; p = 0.043), and extended broad-spectrum antibiotic therapy (OR, 1.112; CI, 1.019-1.213; p = 0.018). Patients with MDRO VAP had significantly longer ICU stays, total hospital stays, and higher hospitalization costs than non-MDRO VAP patients. The in-hospital mortality rate of the MDRO VAP group was significantly higher than that of the non-MDRO VAP group (29.79% vs. 1.61%, p < 0.001). Gram-negative bacilli were the predominant pathogens in MDRO VAP patients (97.87%), with the highest rate of Pseudomonas aeruginosa (29.79%).

Conclusion

Postoperative MDRO VAP in patients undergoing cardiac valvular surgery is linked to severe clinical outcomes. Greater attention should be given to patients with prolonged mechanical ventilation, extended broad-spectrum antibiotic therapy, and preoperative hypoalbuminemia to prevent MDRO VAP infections.

A Retrospective Closed Cohort Study on Distribution of Multidrug-Resistant Bacteria in Ventilator-Associated Pneumonia and its Impact on Patient Outcome

Objectives: Ventilator-associated pneumonia (VAP) is a common and serious nosocomial infection affecting critically ill patients undergoing mechanical ventilation. This study investigated the prevalence of multidrug-resistant (MDR) organisms in VAP, the VAP rate, and the outcomes associated with MDR-VAP. Methods: This retrospective single-center study, conducted in 2022, included adult ICU cases from April 2021 to March 2022, receiving mechanical ventilation for more than 48 h. Patient data were analyzed for demographics, comorbidities, empirical antibiotic use, and outcomes. MDR organisms were identified in respiratory cultures. Results: Among 447 patients, 133 developed VAP, with 96 cases being MDR-VAP. The mean age of the overall VAP population was 52 years, 70% of which were males. The incidence of VAP was 30.0% (95% CI: 25.7%-34.5%), while that of MDR-VAP was 21.6% (95% CI: 17.9%-25.8%). The most prevalent MDR organisms were Acinetobacter species (50%) and Klebsiella pneumoniae (46.9%). Empirical antibiotics were administered in 96% of VAP cases. The overall VAP rate was 38.03/1000 ventilator days. No single antimicrobial agent seemed to offer an empirical cover, as the susceptibility rate for most tested antimicrobials was less than 85%. Patients with MDR-VAP had a low survival rate (64.6%) and were less likely to be extubated at 13.5% compared to non-MDR-VAP (survival rate of 62.2%). COVID-19 patients had a high incidence of MDR VAP, especially with Acinetobacter. Overall, VAP mortality was 57.1%. The median ventilator days were 16 for VAP and only four for non-VAP. Conclusion: Gram-negative organisms, particularly Klebsiella and Acinetobacter, were the main MDR VAP culprits. MDR-VAP exhibited higher morbidity and mortality. A study focused on developing resistance by microorganisms is warranted for further understanding.

Application of double-sleeve endotracheal tube in infection control for icu patients: a randomized controlled trial

BACKGROUND

Poor oral hygiene in patients with tracheal intubation will increase the occurrence of dental plaque and mucosal inflammation, resulting in oral barrier dysfunction. This study aimed to design and evaluate a novel double-lumen endotracheal tube (DETT) and explore its role in infection control, particularly its effects on the oral microenvironment and ventilator-associated pneumonia (VAP).

METHODS

This was a prospective, non-blinded, randomized parallel-controlled trial conducted from July 2024 to September 2024. A total of 115 patients who had been intubated for more than 3 days in a tertiary hospital ICU were enrolled and randomly assigned to either the DETT group (n = 58) or the conventional endotracheal tube (ETT) group (n = 57). Both groups received the same oral care protocols. The DETT group was intubated with the double-lumen endotracheal tube, which included a built-in bite block, while the ETT group used a standard endotracheal tube with a bite block. The primary outcome was the incidence of VAP, while secondary outcomes included oral bacterial colony counts, biofilm formation, BOAS oral health scores, and plaque index.

RESULTS

Compared to the ETT group, the DETT group showed a significant reduction in VAP incidence (χ²=4.382, p < 0.05). The DETT group also had significantly lower oral bacterial colony counts (Z=-7.362, P < 0.05) and biofilm formation (χ²=5.472, p < 0.05), as well as better BOAS scores (Z=-2.774, p < 0.05). However, there were no significant differences between the two groups in pathogenic bacterial presence or plaque index (p > 0.05).

CONCLUSIONS

The novel double-lumen endotracheal tube effectively reduces the total bacterial load in the oral cavity, inhibits biofilm formation, and lowers the incidence of VAP. It also improves oral function and hygiene, contributing to infection control, and holds significant clinical value.

Drug resistance of Pseudomonas aeruginosa based on the isolation sites and types of gastrointestinal diseases: An observational study

INTRODUCTION

We investigated the drug resistance status of Pseudomonas aeruginosa (P. aeruginosa) focusing on its isolation sites and types of diseases.　Materials and methods: A microbiological laboratory database was searched to identify all clinical cultures positive for P. aeruginosa.　Clinicopathologic features and susceptibility of P. aeruginosa to any antibiotics were evaluated in patients admitted to the division of upper (Upper-GI group) or lower gastrointestinal surgery (Lower-GI group).　In addition, we investigated the susceptibility of P. aeruginosa to any antibiotics based on the isolation site.　Results:P. aeruginosa was frequently detected in the sputum and urine of the Upper-GI and Lower-GI groups, respectively.　Among P. aeruginosa isolates from drain discharge, a significantly higher rate of resistance to imipenem, amikacin, and ciprofloxacin was observed; among P. aeruginosa isolates from wounds, a substantially higher proportion had resistance to imipenem and cefozopran in the Upper-GI group.　However, there was no difference between the two groups in the drug resistance of P. aeruginosa isolated from urine, sputum, blood, and ascites.　P. aeruginosa isolated from sputum showed more resistance to imipenem and ciprofloxacin than those isolated from other sites.　Conclusion: There were significant differences in the drug resistance of P. aeruginosa based on the isolation sites and types of diseases.　.

Impact of Multidrug-Resistant Bacterial Colonization on Clinical Characteristics, Antibiotic Treatment, and Clinical Outcomes of Hospital-Acquired Pneumonia

PURPOSE

To determine effects of colonization with multidrug-resistant bacteria (MDRB) in general wards on characteristics, treatment, and prognosis of hospital-acquired pneumonia (HAP).

METHODS

This was a multicenter retrospective cohort study of patients with HAP admitted to 16 tertiary or university hospitals in Korea from July 2019 to December 2019. From the entire cohort, patients who developed pneumonia in general wards with known colonization status before the onset of pneumonia were included in this study. Patients were categorized into a colonization group and a non-colonization group according to MDRB colonization. Patients of the two groups were then compared.

RESULTS

Among a total of 400 patients, 63 were in the MDRB colonization group. HAP caused by MDR-Staphylococcus aureus or MDR-Pseudomonas aeruginosa was more common in the colonization group than in the non-colonization group (24.4% vs. 8.1%, P = 0.006 or 20.0% vs. 5.4%, P = 0.013, respectively). Colonization with certain bacteria was correlated with subsequent infection with the same bacteria. Carbapenem use (36.5% vs. 24.3%, P = 0.044) and appropriateness of initial antibiotics (50.8% vs. 12.8%) were higher in the colonization group than in the non-colonization group. Although in-hospital mortality was similar in the two groups (34.9% vs. 32.9%, P = 0.759), hospital length of stay was longer (38 days vs. 31 days, P = 0.009) and rate of discharge to home was lower (34.1% vs 59.7%, P = 0.002) in the colonization group.

CONCLUSIONS

Colonization with MDRB might influence characteristics and treatment of HAP. However, prognosis of HAP was not associated with MDRB colonization.

Efficacy and safety of different polymyxin-containing regimens for the treatment of pneumonia caused by multidrug-resistant gram-negative bacteria: a systematic review and network meta-analysis

BACKGROUND

The optimal administration of polymyxins for treating multidrug-resistant gram-negative bacterial (MDR-GNB) pneumonia remains unclear. This study aimed to systematically assess the efficacy and safety of three polymyxin-containing regimens by conducting a comprehensive network meta-analysis.

METHODS

We comprehensively searched nine databases. Overall mortality was the primary outcome, whereas the secondary outcomes encompassed microbial eradication rate, clinical success, acute kidney injury, and incidence of bronchospasm. Extracted study data were analyzed by pairwise and network meta-analyses. Version 2 of the Cochrane risk-of-bias tool and the Risk of Bias in Nonrandomized Studies of Interventions (ROBINS-I) assessment tool were used to assess the risk of bias in randomized trials and cohort studies, respectively.

RESULTS

This study included 19 observational studies and 3 randomized controlled trials (RCTs), encompassing 3318 patients. Six studies with high risk of bias were excluded from the primary analysis. In the pairwise meta-analysis, compared to the intravenous (IV) polymyxin-containing regimen, the intravenous plus inhaled (IV + IH) polymyxin-containing regimen showed a significant decrease in overall mortality, while no statistically significant difference was found in the inhaled (IH) polymyxin-containing regimen. The network meta-analysis indicated that the IV + IH polymyxin-containing regimen had significantly lower overall mortality (OR 0.67; 95% confidence interval [CI] 0.50-0.88), higher clinical success rate (OR 1.90; 95% CI 1.20-3.00), better microbial eradication rate (OR 2.70; 95% CI 1.90-3.90) than the IV polymyxin-containing regimen, and significantly better microbial eradication rate when compared with the IH polymyxin-containing regimen (OR 2.30; 95% CI 1.30-4.20). Furthermore, compared with IV + IH and IV polymyxin-containing regimens, the IH polymyxin-containing regimen showed a significant reduction in acute kidney injury.

CONCLUSIONS

Our study indicates that among the three administration regimens, the IV + IH polymyxin-containing regimen may be the most effective for treating MDR-GNB pneumonia, with a significantly lower overall mortality compared to the IV regimen and a considerably higher microbial eradication rate compared to the IH regimen. The IH regimen may be considered superior to the IV regimen due to its substantially lower incidence of acute kidney injury, even though the reduction in overall mortality was not significant.

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.

Empiric Anti-Pseudomonal β-Lactam Monotherapy Versus Fluoroquinolone Combination Therapy in Patients With Hospital-Acquired Pneumonia: A Multicenter Cohort Study With Propensity Score Matching

BACKGROUND

There is insufficient data on the benefits of empiric antibiotic combinations for hospital-acquired pneumonia (HAP). We aimed to investigate whether empiric anti-pseudomonal combination therapy with fluoroquinolones decreases mortality in patients with HAP.

METHODS

This multicenter, retrospective cohort study included adult patients admitted to 16 tertiary and general hospitals in Korea between January 1 and December 31, 2019. Patients with risk factors for combination therapy were divided into anti-pseudomonal non-carbapenem β-lactam monotherapy and fluoroquinolone combination therapy groups. Primary outcome was 30-day mortality. Propensity score matching (PSM) was used to reduce selection bias.

RESULTS

In total, 631 patients with HAP were enrolled. Monotherapy was prescribed in 54.7% (n = 345) of the patients, and combination therapy was prescribed in 45.3% (n = 286). There was no significant difference in 30-day mortality between the two groups (16.8% vs. 18.2%, P = 0.729) or even after the PSM (17.5% vs. 18.2%, P = 0.913). After the PSM, adjusted hazard ratio for 30-day mortality from the combination therapy was 1.646 (95% confidence interval, 0.782-3.461; P = 0.189) in the Cox proportional hazards model. Moreover, there was no significant difference in the appropriateness of initial empiric antibiotics between the two groups (55.0% vs. 56.8%, P = 0.898). The proportion of multidrug-resistant (MDR) pathogens was high in both groups.

CONCLUSION

Empiric anti-pseudomonal fluoroquinolone combination therapy showed no survival benefit compared to β-lactam monotherapy in patients with HAP. Caution is needed regarding the routine combination of fluoroquinolones in the empiric treatment of HAP patients with a high risk of MDR.

Clinical Features and Outcomes of VAP Due to Multidrug-Resistant Klebsiella spp.: A Retrospective Study Comparing Monobacterial and Polybacterial Episodes

VAP due to multidrug-resistant (MDR) bacteria is a frequent infection among patients in ICUs. Patient characteristics and mortality in mono- and polybacterial cases of VAP may differ. A single-centre, retrospective 3-year study was conducted in the four ICUs of a Lithuanian referral university hospital, aiming to compare both the clinical features and the 60-day ICU all-cause mortality of monobacterial and polybacterial MDR Klebsiella spp. VAP episodes. Of the 86 MDR Klebsiella spp. VAP episodes analyzed, 50 (58.1%) were polybacterial. The 60-day mortality was higher (p < 0.05) in polybacterial episodes: overall (50.0 vs. 27.8%), in the sub-group with less-severe disease (SOFA < 8) at VAP onset (45.5 vs. 15.0%), even with appropriate treatment (41.7 vs. 12.5%), and the sub-group of extended drug-resistant (XDR) Klebsiella spp. (46.4 vs. 17.6%). The ICU mortality (44.0 vs. 22.5%) was also higher in the polybacterial episodes. The monobacterial MDR Klebsiella spp. VAP was associated (p < 0.05) with prior hospitalization (61.1 vs. 40.0%), diabetes mellitus (30.6 vs. 5.8%), obesity (30.6 vs. 4.7%), prior antibiotic therapy (77.8 vs. 52.0%), prior treatment with cephalosporins (66.7 vs. 36.0%), and SOFA cardiovascular ≥ 3 (44.4 vs. 10.0%) at VAP onset. Patients with polybacterial VAP were more likely (p < 0.05) to be comatose (22.2 vs. 52.0%) and had a higher SAPS II score (median [IQR] 45.0 [35.25-51.1] vs. 50.0 [40.5-60.75]) at VAP onset. Polybacterial MDR Klebsiella spp. VAP had distinct demographic and clinical characteristics compared to monobacterial, and was associated with poorer outcomes.

Efficacy and safety of intravenous combined with aerosolised polymyxin versus intravenous polymyxin alone in the treatment of multidrug-resistant gram-negative bacterial pneumonia: A systematic review and meta-analysis

Background

Previous studies have questioned the efficacy and safety of intravenous combined with aerosolised (IV + AS) polymyxin versus intravenous (IV) polymyxin alone in the treatment of patients with multidrug-resistant gram-negative bacterial (MDR-GNB) pneumonia. Therefore, we conducted a meta-analysis to evaluate the efficacy and safety of IV + AS polymyxin in the treatment of MDR-GNB pneumonia.

Methods

We identified all relevant studies by searching the PubMed, EMBASE and Cochrane library databases from their inception to May 31, 2022. All included studies were evaluated using the Newcastle Ottawa scale (NOS) checklist. The summary relative risk (RR) and 95% confidence interval (CI) were used to determine the outcome differences between the IV + AS and the IV groups. Subgroup analysis was performed based on population, polymyxin dose and kinds of polymyxin.

Results

A total of 16 studies were included in the meta-analysis. The IV + AS group had lower mortality (RR = 0.86, 95% CI: 0.77-0.97, P = 0.01) than the IV group. Subgroup analysis revealed that IV + AS polymyxin could reduce mortality only when used in low doses. Simultaneously, the IV + AS group outperformed the IV group in terms of clinical response rate, clinical cure rate, microbiological eradication and duration of mechanical ventilation. The duration of hospitalisation and the incidence of nephrotoxicity did not differ significantly between the two groups.

Conclusions

IV + AS polymyxin is beneficial in the treatment of MDR-GNB pneumonia. It could lower patient mortality and improve clinical and microbial outcomes without increasing the risk of nephrotoxicity. However, retrospective analysis in the majority of studies and heterogeneity between studies implies that our findings must be interpreted carefully.

Disinfectant Susceptibility of Third-Generation-Cephalosporin/Carbapenem-Resistant Gram-Negative Bacteria Isolated from the Oral Cavity of Residents of Long-Term-Care Facilities

We have recently reported the isolation of third-generation-cephalosporin-resistant Gram-negative bacteria from the oral cavity of residents of a long-term-care facility (LTCF). Since disinfectants are often used in the oral cavity, it is important to investigate the disinfectant susceptibility of oral bacteria. Here, we evaluated the susceptibilities of Gram-negative antimicrobial-resistant bacteria (GN-ARB), including Pseudomonas, Acinetobacter, and Enterobacteriaceae, obtained from the oral cavity of residents of LTCFs to povidone-iodine (PVPI), cetylpyridinium chloride (CPC), benzalkonium chloride (BZK), and chlorhexidine chloride (CHX). We also evaluated the susceptibilities of isolates from the rectum to the same agents to compare the susceptibility profiles of oral and rectal isolates. Next, we investigated the relationship between their susceptibility and disinfectant resistance genes delineated by whole-genome sequencing of the isolates. Additionally, we evaluated the correlation between disinfectant-resistant GN-ARB and clinical information. In oral GN-ARB, the MIC of PVPI showed almost identical values across isolates, while the MICs of CPC, BZK, and CHX showed a wide range of variation among species/strains. In particular, Pseudomonas aeruginosa exhibited high-level resistance to CPC and BZK. The disinfectant susceptibility of rectal GN-ARB showed a tendency similar to that of oral GN-ARB. The presence of qacEΔ1 was correlated with CPC/BZK resistance in P. aeruginosa, while other species exhibited no correlation between qacEΔ1 and resistance. Multiple analyses showed the correlation between the presence of CPC-resistant bacteria in the oral cavity and tube feeding. In conclusion, we found that some oral GN-ARB isolates showed resistance to not only antibiotics but also disinfectants. IMPORTANCE Antibiotic-resistant bacteria (ARB) are becoming a serious concern worldwide. We previously reported the isolation of third-generation-cephalosporin-resistant Gram-negative bacteria from the oral cavity of residents of a long-term-care facility (LTCF). To prevent infection with ARB in hospitals and eldercare facilities, we must pay more attention to the use of not only antibiotics but also disinfectants. However, the effect of disinfectants on ARB is unclear. In this study, we evaluated the susceptibility of Gram-negative ARB (GN-ARB) from the oral cavity of residents of LTCFs to some disinfectants that are often used for the oral cavity; we found that some isolates showed resistance to several disinfectants. This is the first comprehensive analysis of the disinfectant susceptibility of oral GN-ARB. These results provide some important information for infection control and suggest that disinfectants should be applied carefully.

The immune responses to different Uropathogens call individual interventions for bladder infection

Urinary tract infection (UTI) caused by uropathogens is the most common infectious disease and significantly affects all aspects of the quality of life of the patients. However, uropathogens are increasingly becoming antibiotic-resistant, which threatens the only effective treatment option available-antibiotic, resulting in higher medical costs, prolonged hospital stays, and increased mortality. Currently, people are turning their attention to the immune responses, hoping to find effective immunotherapeutic interventions which can be alternatives to the overuse of antibiotic drugs. Bladder infections are caused by the main nine uropathogens and the bladder executes different immune responses depending on the type of uropathogens. It is essential to understand the immune responses to diverse uropathogens in bladder infection for guiding the design and development of immunotherapeutic interventions. This review firstly sorts out and comparatively analyzes the immune responses to the main nine uropathogens in bladder infection, and summarizes their similarities and differences. Based on these immune responses, we innovatively propose that different microbial bladder infections should adopt corresponding immunomodulatory interventions, and the same immunomodulatory intervention can also be applied to diverse microbial infections if they share the same effective therapeutic targets.

Clinical Features and Outcomes of Monobacterial and Polybacterial Episodes of Ventilator-Associated Pneumonia Due to Multidrug-Resistant Acinetobacter baumannii

Multidrug-resistant A. baumannii (MDRAB) VAP has high morbidity and mortality, and the rates are constantly increasing globally. Mono- and polybacterial MDRAB VAP might differ, including outcomes. We conducted a single-center, retrospective (January 2014−December 2016) study in the four ICUs (12−18−24 beds each) of a reference Lithuanian university hospital, aiming to compare the clinical features and the 30-day mortality of monobacterial and polybacterial MDRAB VAP episodes. A total of 156 MDRAB VAP episodes were analyzed: 105 (67.5%) were monomicrobial. The 30-day mortality was higher (p < 0.05) in monobacterial episodes: overall (57.1 vs. 37.3%), subgroup with appropriate antibiotic therapy (50.7 vs. 23.5%), and subgroup of XDR A. baumannii (57.3 vs. 36.4%). Monobacterial MDRAB VAP was associated (p < 0.05) with Charlson comorbidity index ≥3 (67.6 vs. 47.1%), respiratory comorbidities (19.0 vs. 5.9%), obesity (27.6 vs. 9.8%), prior hospitalization (58.1 vs. 31.4%), prior antibiotic therapy (99.0 vs. 92.2%), sepsis (88.6 vs. 76.5%), septic shock (51.9 vs. 34.6%), severe hypoxemia (23.8 vs. 7.8%), higher leukocyte count on VAP onset (median [IQR] 11.6 [8.4−16.6] vs. 10.9 [7.3−13.4]), and RRT need during ICU stay (37.1 vs. 17.6%). Patients with polybacterial VAP had a higher frequency of decreased level of consciousness (p < 0.05) on ICU admission (29.4 vs. 14.3%) and on VAP onset (29.4 vs. 11.4%). We concluded that monobacterial MDRAB VAP had different demographic/clinical characteristics compared to polybacterial and carried worse outcomes. These important findings need to be validated in a larger, prospective study, and the management implications to be further investigated.

Risk Factors and Protective Factors against Ventilator-Associated Pneumonia-A Single-Center Mixed Prospective and Retrospective Cohort Study

Introduction: Understanding the factors associated with the development of ventilator-associated pneumonia (VAP) in critically ill patients in the intensive care unit (ICU) will allow for better prevention and control of VAP. The aim of the study was to evaluate the incidence of VAP, as well as to determine risk factors and protective factors against VAP. Design: Mixed prospective and retrospective cohort study. Methods: The cohort involved 371 critically ill patients who received standard interventions to prevent VAP. Additionally, patients in the prospective cohort were provided with continuous automatic pressure control in tapered cuffs of endotracheal or tracheostomy tubes and continuous automatic subglottic secretion suction. Logistic regression was used to assess factors affecting VAP. Results: 52 (14%) patients developed VAP, and the incidence density of VAP per 1000 ventilator days was 9.7. The median days to onset of VAP was 7 [4; 13]. Early and late onset VAP was 6.2% and 7.8%, respectively. According to multivariable logistic regression analysis, tracheotomy (OR = 1.6; CI 95%: 1.1 to 2.31), multidrug-resistant bacteria isolated in the culture of lower respiratory secretions (OR = 2.73; Cl 95%: 1.83 to 4.07) and ICU length of stay >5 days (OR = 3.32; Cl 95%: 1.53 to 7.19) were positively correlated with VAP, while continuous control of cuff pressure and subglottic secretion suction used together were negatively correlated with VAP (OR = 0.61; Cl 95%: 0.43 to 0.87). Conclusions: Tracheotomy, multidrug-resistant bacteria, and ICU length of stay >5 days were independent risk factors of VAP, whereas continuous control of cuff pressure and subglottic secretion suction used together were protective factors against VAP.

Colonization of Extended-spectrum β-lactamase producing Enterobacterales and meticillin-resistant S. aureus in the intensive care unit at a tertiary hospital in Tanzania: Implications for Infection control and prevention

Background

Multi-drug resistant (MDR) bacteria pose a major global threat to public-health and are of particular concern to hospitalized intensive care unit (ICU) patients. This study aimed at addressing the burden of MDR and the associated factors at admission to ICU.

Methods

This was a cross-sectional study conducted at the ICU of a tertiary hospital in Tanzania. Rectal and anterior nares swabs were collected within 48 hours of ICU admission to screen for extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-PE) and meticillin-resistant Staphylococcus aureus (MRSA), respectively.

Results

The proportion of fecal carriage for ESBL-PE at admission to ICU was 54.54% (95% CI, 47.52–61.39), and nasal carriage for MRSA was 9.32% (95%CI, 5.67–14.93). The nasal MRSA colonization (OR = 1.52) and fecal carriage for ESBL-PE (OR=1.38) were more likely in participants who had received antibiotics before ICU admission than not, but association was not statistically significant. Hospitalization for ≥2 days (OR=1.18) was associated with fecal carriage of ESBL-PE, though not statistically significant. Overall, 66% and 73.5% of patients received antibiotics before and upon admission to ICU, respectively. Ceftriaxone, metronidazole and meropenem were commonly prescribed antibiotics. More than 84% of Enterobacterales were resistant to ciprofloxacin and trimethoprim-sulfamethoxazole, and 2.90% were resistant to meropenem. MRSA isolates showed a high rate of resistance to gentamicin and erythromycin.

Conclusion

MDR bacteria are common in patients admitted to ICU. To reduce the risk associated with MDR, we recommend use of simple screening methods to screen for MDR at ICU admission as part of infection control and prevention.