Aetiological agents of ventilator-associated pneumonia and its resistance pattern - a threat for treatment

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.

Antimicrobial Susceptibility among Pathogens Isolated in Early- versus Late-Onset Ventilator-Associated Pneumonia

Ventilator-associated pneumonia (VAP) is associated with increased hospital stay and high morbidity and mortality in critically ill patients. The aims of this study were to (i) determine the incidence of multidrug-resistant (MDR) pathogens in the first episodes of VAP and to assess potential differences in bacterial profiles of subjects with early- versus late-onset VAP. This was a retrospective cohort study over a period of 18 months including all patients who had a first episode of VAP confirmed by positive bacterial culture. Subjects were distributed into two groups according to the number of intubation days: early-onset VAP (<5 days) or late-onset VAP (≥5 days). The primary endpoint was the nature of causative pathogens and their resistance profiles. Sixty patients were included, 29 men and 31 women, with an average age of 38 ± 16 years. The IGS 2 at admission was 40.5 [32–44] and APACHE was 19 [15–22]. Monomicrobial infections were diagnosed in 77% of patients (n = 46). The most frequently isolated bacteria were A. baumannii, 53% (n = 32); P. aeruginosa in 37% (n = 22); Enterobacterales in 28% (n = 17) and S. aureus in 5% (n = 3). Ninety-seven percent of the bacteria were MDR. The VAP group comprised 36 (60%) episodes of early-onset VAP and 24 (40%) episodes of late-onset VAP. There was no significant difference in the distribution of the bacterial isolates, nor in terms of antibacterial resistances between early- and late-onset VAPs. Our data support recent observations that there is no microbiological difference in the prevalence of potential MDR pathogens or in their resistance profiles associated with early- versus late-onset VAPs, especially in countries with high rates of MDR bacteria.

Pathogenesis-Targeted Preventive Strategies for Multidrug Resistant Ventilator-Associated Pneumonia: A Narrative Review

Ventilator-associated pneumonia (VAP) is the most common hospital-acquired infection in the intensive care unit (ICU), accounting for relevant morbidity and mortality among critically ill patients, especially when caused by multidrug resistant (MDR) organisms. The rising problem of MDR etiologies, which has led to a reduction in treatment options, have increased clinician’s attention to the employment of effective prevention strategies. In this narrative review we summarized the evidence resulting from 27 original articles that were identified through a systematic database search of the last 15 years, focusing on several pathogenesis-targeted strategies which could help preventing MDR-VAP. Oral hygiene with Chlorhexidine (CHX), CHX body washing, selective oral decontamination (SOD) and/or digestive decontamination (SDD), multiple decontamination regimens, probiotics, subglottic secretions drainage (SSD), special cuff material and shape, silver-coated endotracheal tubes (ETTs), universal use of gloves and contact isolation, alcohol-based hand gel, vaporized hydrogen peroxide, and bundles of care have been addressed. The most convincing evidence came from interventions directly addressed against the key factors of MDR-VAP pathogenesis, especially when they are jointly implemented into bundles. Further research, however, is warranted to identify the most effective combination.

A Survey of Genotype and Resistance Patterns of Ventilator-Associated Pneumonia Organisms in ICU Patients

BACKGROUND

Ventilator-Associated Pneumonia (VAP) occurs in hospitalized patients who have undergone intubation and mechanical ventilation for more than 48 hours. Patients referred to the Intensive Care Unit (ICU) are also affected by VAP due to specific conditions, especially by Gram-negative pathogens with advanced drug resistance. In this study, the pattern of antibiotic resistance of gram negative bacteria isolated from tracheal culture of VAP patients was investigated in ICU.

MATERIALS AND METHODS

In this cross-sectional study, tracheal samples were collected from VAP patients admitted in the hospital's ICU from March 2017-February 2018. After isolation, bacterial isolates were identified using biochemical tests. Then, antimicrobial resistance pattern of these isolates was investigated using standard disc diffusion and E-test methods. Multiplex PCR were used to detect the blaOXA-23-like, blaOXA-51-like, blaOXA-24-like, and blaOXA-58-like genes among Acinetobacter baumannii (A. baumannii) isolates.

RESULTS

A total of 29 bacterial isolates were isolated from ICU patients, which were A. baumannii, Pseudomonas aeruginosa (P. aeruginosa), Klebsiella pneumoniae (K. pneumoniae) and candida spp, with prevalence of 38, 27.5, 13.8, and 20.7%, respectively. Antibiotic susceptibility test of isolates indicated that almost all isolates showed Multi-Drug Resistance (MDR) pattern. The A. baumannii isolates were resistant to ciprofloxacin and piperacillin-tazobactam, but ampicillin-sulbactam and colistin had better results. Ciprofloxacin, meropenem and colistin were effective against P. aeruginosa isolates, but other antibiotics were less effective and Colistin, Levofloxacin (LVX) and Piperacilin/Tazobactam were the best antibiotics that were effective on the isolates of K. pneumonia.

CONCLUSION

According to the present study, high resistance to most antibiotics in gram negative bacilli showed that antibiotic therapy should be based on the type of bacteria isolated by tracheal culture and, as far as possible, combination therapies should be used to maximize the coverage of other possible pathogens, and antibiotic resistance in ICU.

Mechanical ventilator as a major cause of infection and drug resistance in intensive care unit

Ventilator-associated pneumonia (VAP) is the most frequent infection in intensive care units (ICU). It is associated with high rates of long morbidity and mortality. Management of a case of VAP is often said to add $40,000 to hospital costs USA. All these data directed our interest to study the etiology, risk factors, and antibiotic susceptibility patterns of VAP in ICU of Tanta University Hospital. This study included 36 cases of VAP. Endotracheal aspirates were obtained from all cases and microbiologically analyzed. Samples were collected over 1 year. Forty-two strains were isolated from 28 cases, while eight cases showed no bacterial growth. The most frequent organism was Staphylococcus aureus (30.95%), followed by Acinetobacter baumannii and Pseudomonas aeruginosa (21.43% for each), and the least common was Staphylococcus epidermidis (2.38%). Multi-drug resistance was detected in (50%) of the isolated bacteria in this study. Imipenem, amikacin, linezolid, vancomycin, and levofloxacin are recommended to be the most effective drugs in management of VAP. VAP is a serious problem in ICU carrying many risks for the patient live. Regimens of empirical treatment should take in consideration the update in the bacterial etiology and antibiotic susceptibility patterns of VAP.

Management of infections in critically ill returning travellers in the intensive care unit-II: clinical syndromes and special considerations in immunocompromised patients

This position paper is the second ESCMID Consensus Document on this subject and aims to provide intensivists, infectious disease specialists, and emergency physicians with a standardized approach to the management of serious travel-related infections in the intensive care unit (ICU) or the emergency department. This document is a cooperative effort between members of two European Society of Clinical Microbiology and Infectious Diseases (ESCMID) study groups and was coordinated by Hakan Leblebicioglu and Jordi Rello for ESGITM (ESCMID Study Group for Infections in Travellers and Migrants) and ESGCIP (ESCMID Study Group for Infections in Critically Ill Patients), respectively. A relevant expert on the subject of each section prepared the first draft which was then edited and approved by additional members from both ESCMID study groups. This article summarizes considerations regarding clinical syndromes requiring ICU admission in travellers, covering immunocompromised patients.

In vitro potency of amikacin and comparators against E. coli, K. pneumoniae and P. aeruginosa respiratory and blood isolates

Background

The purpose of this study was to define the potency of amikacin and comparator agents against a collection of blood and respiratory nosocomial isolates implicated in ICU based pulmonary infections gathered from US hospitals.

Methods

Minimum inhibitory concentrations of amikacin, aztreonam, cefepime, ceftazidime, ceftolozane/tazobactam, ceftriaxone, ciprofloxacin, imipenem, meropenem, piperacillin/tazobactam and tobramycin were tested against 2460 Gram-negative isolates. Amikacin had 96 % susceptibility against the combined E. coli and K. pneumoniae isolates and 95 % susceptibility against P. aeruginosa.

Results

Ninety-six percent of all of isolates tested were susceptible (i.e., MICs ≤16 mg/L) to amikacin by current laboratory standards which demonstrates a high level of activity to combat infections caused by these organisms including ESBL, MDR, β-lactam and fluoroquinolone resistant strains. Moreover, 99 % of all organisms had amikacin MICs ≤64 mg/L.

Conclusions

Overall, these data highlight the continued potency of amikacin and suggest that the achievable lung concentrations of approximately 5000 mg/L with the administration of the amikacin by inhalation (Amikacin Inhale, BAY41-6551) will exceed the MICs typically observed for P. aeruginosa, E. coli and K. pneumoniae in the hospital setting.

Case fatality rate related to nosocomial and ventilator-associated pneumonia in an ICU: a single-centre retrospective cohort study

BACKGROUND

Nosocomial pneumonia (NP) and ventilator associated pneumonia (VAP) have been associated with financially significant economic burden and increased case fatality rate in adult intensive care units (ICUs). This study was designed to evaluate case fatality rate among patients with NP and VAP in a respiratory ICU.

METHODS

In 2008-2013, VAP and NP in the ICUs were included in this retrospective single-centre cohort study. Data on demographics, co-morbidities, severity of illness, mechanical ventilation, empirical treatment, length of hospital stay and laboratory findings were recorded in each group, as were case fatality rate during ICU admission and after discharge including short-term (28-day) and long-term (a year) case fatality rate.

RESULTS

A total of 108 patients with VAP (n = 64, median (IQR) age: 70 (61-75) years, 67.2% were men) or NP (n = 44, median (IQR) age: 68 (62-74) years, 68.2% were men) were found. Appropriate empirical antibiotic therapy was identified only in 45.2 and 42.9% of patients with VAP and NP, respectively. Overall case fatality rate in VAP and NP (81.3 vs 84.1), ICU case fatality rate (42.2 vs 45.5%), short-term case fatality rate (15.6 vs 27.3%) and long-term case fatality rate (23.4 vs 11.4%) were similar between VAP and NP groups along with occurrence 50% of case fatality rate cases in the first 2 months and 90% within the first year of discharge. Multivariate analysis showed that chronic obstructive pulmonary disease (COPD) (HR: 3.15, 95% CI: 1.06-9.38; p = 0.039) and presence of septic shock (HR: 3.83, 95% CI: 1.26-11.60; p = 0.018) were independently associated with lower survival.

CONCLUSION

In conclusion, our findings in a retrospective cohort of respiratory ICU patients with VAP or NP revealed high ICU, short- and long-term case fatality rates within 1 year of diagnosis, regardless of the diagnosis of NP after 48 h of initial admission or after induction of ventilator support. COPD and presence of septic shock are associated with high fatality rate and our findings speculate that as increasing compliance with infection control programs and close monitoring especially in 2 months of discharge might reduce high-case fatality rate in patients with VAP and NP.

A 2015 Update on Ventilator-Associated Pneumonia: New Insights on Its Prevention, Diagnosis, and Treatment

Ventilator-associated pneumonia (VAP), an infection of the lower respiratory tract which occurs in association with mechanical ventilation, is one of the most common causes of nosocomial infection in the intensive care unit (ICU). VAP causes significant morbidity and mortality in critically ill patients including increased duration of mechanical ventilation, ICU stay and hospitalization. Current knowledge for its prevention, diagnosis and management is therefore important clinically and is the basis for this review. We discuss recent changes in VAP surveillance nomenclature incorporating ventilator-associated conditions and ventilator-associated events, terms recently proposed by the Centers for Disease Control. To the extent possible, we rely predominantly on data from randomized control trials (RCTs) and meta-analyses.

Microbial composition and antibiotic resistance of biofilms recovered from endotracheal tubes of mechanically ventilated patients

In critically ill patients, breathing is impaired and mechanical ventilation, using an endotracheal tube (ET) connected to a ventilator, is necessary. Although mechanical ventilation is a life-saving procedure, it is not without risk. Because of several reasons, a biofilm often forms at the distal end of the ET and this biofilm is a persistent source of bacteria which can infect the lungs, causing ventilator-associated pneumonia (VAP). There is a link between the microbial flora of ET biofilms and the microorganisms involved in the onset of VAP. Culture dependent and independent techniques were already used to identify the microbial flora of ET biofilms and also, the antibiotic resistance of microorganisms obtained from ET biofilms was determined. The ESKAPE pathogens play a dominant role in the onset of VAP and these organisms were frequently identified in ET biofilms. Also, antibiotic resistant microorganisms were frequently present in ET biofilms. Members of the normal oral flora were also identified in ET biofilms but it is thought that these organisms initiate ET biofilm formation and are not directly involved in the development of VAP.