[Collection of tracheal aspirate: safety and microbiological concordance between two techniques]

Rapid Detection of Carbapenemase-Producing Multidrug-Resistant (MDR) Pathogens by Modified Carba NP Test in Ventilator-Associated Pneumonia (VAP) in Elderly Patients

Background Ventilator-associated pneumonia (VAP) is defined as pneumonia that develops 48 hours or more after endotracheal intubation or tracheostomy and is brought on by infectious organisms that are not present or incubating during mechanical ventilation. Multidrug-resistant organisms originate primarily from the hospital environment and significantly contribute to ventilator-associated pneumonia. These organisms pose a severe threat, leading to a higher mortality rate due to their resistance to more potent antibiotics. Methods The study aims to assess the efficacy of the modified Carba NP test in detecting carbapenemase-producing bacteria in geriatric VAP patients. Results Forty (38 gram-negative and 2 gram-positive) pathogens were isolated from VAP patients. The isolates were identified using standard laboratory protocol; Acinetobacter spp. (n=16; 40% ), followed by Klebsiella pneumoniae (n=13; 32.5%), is the most common organism isolated. Seventeen (44.73%) were multi-drug resistant gram-negative bacteria. The carbapenemase producers were detected by the Kirby-Bauer disc diffusion method and compared with the modified Carba NP test with a turnaround time of 12-18 hrs in comparison to the disk diffusion test which requires additional 12hrs. Carbapenemase production was seen in 12 (70.59%) MDR isolates (7-Acinetobacter spp, 3-Klebsiella pneumonia, 1-Escherichia coli, and 1-Pseudomonas aeruginosa).  Conclusion Modified Carba NP can be used as a rapid test to detect carbapenemase production, and it can replace the traditional disk diffusion method of detecting carbapenemase production. This test plays a crucial role in the management of critical patients by saving 12-18 hours to determine the most appropriate and effective antibiotic treatment. This timely decision is essential in preventing sepsis caused by localized infections.

C. R, Thwaites L, Basnyat B, Baker S, Karkey A. Epidemiology, etiology, and diagnosis of health care acquired pneumonia including ventilator-associated pneumonia in Nepal

Epidemiologic data regarding health care acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) from Nepal are negligible. We conducted a prospective observational cohort study in the intensive care unit (ICU) of a major tertiary hospital in Nepal between April 2016 and March 2018, to calculate the incidence of VAP, and to describe clinical variables, microbiological etiology, and outcomes. Four hundred and thirty-eight patients were enrolled in the study. Demographic data, medical history, antimicrobial administration record, chest X-ray, biochemical, microbiological and haematological results, acute physiology and chronic health evaluation II score and the sequential organ failure assessment scores were recorded. Categorical variables were expressed as count and percentage and analyzed using the Fisher's exact test. Continuous variables were expressed as median and interquartile range and analyzed using Kruskal-Wallis rank sum test and the pairwise Wilcoxon rank-sum test. 46.8% (205/438) of the patients required intubation. Pneumonia was common in both intubated (94.14%; 193/205) and non-intubated (52.36%; 122/233) patients. Pneumonia developed among intubated patients in the ICU had longer days of stay in the ICU (median of 10, IQR 5-15, P< 0.001) when compared to non-intubated patients with pneumonia (median of 4, IQR 3-6, P< 0.001). The incidence rate of VAP was 20% (41/205) and incidence density was 16.45 cases per 1,000ventilator days. Mortality was significantly higher in patients with pneumonia requiring intubation (44.6%, 86/193) than patients with pneumonia not requiring intubation (10.7%, 13/122, p<0.001, Fisher's exact test). Gram negative bacteria such as Klebsiella and Acinetobacter species were the dominant organisms from both VAP and non-VAP categories. Multi-drug resistance was highly prevalent in bacterial isolates associated with VAP (90%; 99/110) and non-VAP categories (81.5%; 106/130). HAP including VAP remains to be the most prevalent hospital-acquired infections (HAIs) at Patan hospital. A local study of etiological agents and outcomes of HAP and VAP are required for setting more appropriate guidelines for management of such diseases.

Ventilator-Associated Pneumonia: Diagnostic Test Stewardship and Relevance of Culturing Practices

PURPOSE OF REVIEW

Ventilator-associated pneumonia (VAP) is one of the most common infections in the ICU. Prompt diagnosis is vital as mortality increases with delayed antibiotic therapy. However, accurate diagnosis is challenging due to non-specific clinical features in a complicated patient cohort. Microbiological culture data remains a crucial aspect in confirming diagnosis.

RECENT FINDINGS

Literature data comparing the benefit of invasive respiratory sampling to non-invasive is inconclusive. Differences in culturing practices translate in overidentification of organisms of unclear significance. Positive culture data in a low pre-test probability does not differentiate between true infection and colonization resulting in overtreatment. Furthermore, there are also opportunities for modifying the reporting of respiratory tract cultures that can better guide antimicrobial therapy. Under the umbrella of antimicrobial stewardship, diagnostic stewardship can be incorporated to create a systematic approach that would target culturing practices to match the right pre-test probability. Ideal outcome will be targeting cultures to the right patient population and minimizing unnecessary treatment.

MERS-CoV infection is associated with downregulation of genes encoding Th1 and Th2 cytokines/chemokines and elevated inflammatory innate immune response in the lower respiratory tract

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MERS-CoV infection downregulates Th1 and Th2 cytokines and chemokines.

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MERS-CoV infection provokes high levels of IL-1α, IL-1β and IL-8 (CXCL8).

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Inflammatory cytokines/chemokines correlate with MERS-CoV case fatality rate.

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Th1/Th2 downregulation may contribute to severe infection and evolution of ARDS.

MERS-CoV, a highly pathogenic virus in humans, is associated with high morbidity and case fatality. Inflammatory responses have a significant impact on MERS-CoV pathogenesis and disease outcome. However, CD4⁺ T-cell induced immune responses during acute MERS-CoV infection are barely detectable, with potent inhibition of effector T cells and downregulation of antigen presentation. The local pulmonary immune response, particularly the Th1 and Th2-related immune response during acute severe MERS-CoV infection is not fully understood. In this study, we offer the first insights into the pulmonary gene expression profile of Th1 and Th2-related cytokines/chemokines (Th1 & Th2 responses) during acute MERS-CoV infection using RT² Profiler PCR Arrays. We also quantified the expression level of primary inflammatory cytokines/chemokines. Our results showed a downregulation of Th2, inadequate (partial) Th1 immune response and high expression levels of inflammatory cytokines IL-1α and IL-1β and the neutrophil chemoattractant chemokine IL-8 (CXCL8) in the lower respiratory tract of MERS-CoV infected patients. Moreover, we identified a high viral load in all included patients. We also observed a correlation between inflammatory cytokines, Th1, and Th2 downregulation and the case fatality rate. Th1 and Th2 response downregulation, high expression of inflammatory cytokines, and high viral load may contribute to lung inflammation, severe infection, the evolution of pneumonia and ARDS, and a higher case fatality rate. Further study of the molecular mechanisms underlying the Th1 and Th2 regulatory pathways will be vital for active vaccine development and the identification of novel therapeutic strategies.

Safety profile of blind bronchial sampling-A prospective study in pediatric intensive care unit

OBJECTIVE

To study the safety profile of blind bronchial sampling in mechanically ventilated children.

DESIGN

Prospective interventional study.

SETTING

Tertiary level pediatric intensive care unit of a multispecialty hospital.

PATIENTS

Children aged 1 month to 16 years on mechanical ventilator for ≥48 h, were assessed by clinical pulmonary infection score for ventilator-associated pneumonia (VAP).

INTERVENTIONS

Blind bronchial sampling was performed following standard procedural guidelines. The hemodynamic, ventilation parameters, and arterial blood gases done before, and in next 24 h post procedure were recorded and compared.

MEASUREMENTS AND MAIN RESULTS

Among the 40 enrolled children, VAP was suspected at 5.8 ± 3.7 days post intubation with insignificant increase in median (IQR) PELOD score to 15 (11-23) from 13.5 (11-23) (P value 0.29). A statistically significant increase in mean blood pressure (75.5 ± 14.7 to 79.1 ± 14.2, P 0.04) and transient drop in SpO₂ (98.2 ± 2.3 to 92.2 ± 9.2, P < 0.001) were noted with insignificant change in heart rate (128.7 ± 25.6 vs 132.0 ± 30.8, P 0.52), though these variations were clinically not significant. There were no major complications like significant airway bleed, arrhythmia, air leaks, edema, and change in pulmonary infiltrates during the procedure. There were no significant (either clinical or statistical) effects of BBS procedure, whether transient or prolonged, on ventilatory requirements or gas exchange parameters.

CONCLUSIONS

Blind bronchial sampling is a safe procedure in children with no major adverse events related to hemodynamics, oxygenation, and ventilation parameters.