How to treat VAP due to MDR pathogens in ICU patients

Anti-Pseudomonas aeruginosa Vaccines and Therapies: An Assessment of Clinical Trials

Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that causes high morbidity and mortality in cystic fibrosis (CF) and immunocompromised patients, including patients with ventilator-associated pneumonia (VAP), severely burned patients, and patients with surgical wounds. Due to the intrinsic and extrinsic antibiotic resistance mechanisms, the ability to produce several cell-associated and extracellular virulence factors, and the capacity to adapt to several environmental conditions, eradicating P. aeruginosa within infected patients is difficult. Pseudomonas aeruginosa is one of the six multi-drug-resistant pathogens (ESKAPE) considered by the World Health Organization (WHO) as an entire group for which the development of novel antibiotics is urgently needed. In the United States (US) and within the last several years, P. aeruginosa caused 27% of deaths and approximately USD 767 million annually in health-care costs. Several P. aeruginosa therapies, including new antimicrobial agents, derivatives of existing antibiotics, novel antimicrobial agents such as bacteriophages and their chelators, potential vaccines targeting specific virulence factors, and immunotherapies have been developed. Within the last 2-3 decades, the efficacy of these different treatments was tested in clinical and preclinical trials. Despite these trials, no P. aeruginosa treatment is currently approved or available. In this review, we examined several of these clinicals, specifically those designed to combat P. aeruginosa infections in CF patients, patients with P. aeruginosa VAP, and P. aeruginosa-infected burn patients.

Meropenem-Resistant Pandoraea Pneumonia in a Critically Ill Patient With COVID-19

Among patients infected with respiratory viruses, primary coinfection or secondary bacterial pneumonia is common in the severely ill. Pandoraea are multi-drug resistant gram-negative bacilli that have been newly classified in the past 20 years. We present the first reported case of Pandoraea co-infection with SARS-CoV-2 infection. A critically ill gentleman with COVID-19 in acute respiratory distress syndrome (ARDS) requiring mechanical ventilation developed ventilator-associated bacterial pneumonia (VAP). Initial sputum cultures grew Pandoraea species, with subsequent cultures growing P. aeruginosa, and K. pneumoniae as well. The patient failed to improve despite several antibiotic regimens including meropenem. Send-out reference laboratory testing of the Pandoraea species showed susceptibility to amikacin, ciprofloxacin, levofloxacin, imipenem, and minocycline, but resistance to aztreonam, cefepime, ceftazidime, and meropenem. The patient had deteriorated to multi-organ failure by the time minocycline was initiated, and his family had transitioned him into hospice care. Carbapenems are vital agents in the treatment of VAP. Pandoraea species are often resistant to meropenem but often retain in-vitro sensitivity to imipenem-cilastin. Although mainly isolated from respiratory specimens of patients with cystic fibrosis, cases of infection in non-cystic fibrosis patients have been increasingly recognized. The presentation of this case aims to increase awareness of the high drug resistance of this rising species and reduce delays in treatment, especially in COVID-19 coinfection.

Place in Therapy of the Newly Available Armamentarium for Multi-Drug-Resistant Gram-Negative Pathogens: Proposal of a Prescription Algorithm

The worldwide propagation of antimicrobial resistance represents one of the biggest threats to global health and development. Multi-drug-resistant organisms (MDROs), including carbapenem-resistant non-fermenting Gram-negatives and Enterobacterales, present a heterogeneous and mutating spread. Infections by MDRO are often associated with an unfavorable outcome, especially among critically ill populations. The polymyxins represented the backbone of antibiotic regimens for Gram-negative MDROs in recent decades, but their use presents multiple pitfalls. Luckily, new agents with potent activity against MDROs have become available in recent times and more are yet to come. Now, we have the duty to make the best use of these new therapeutic tools in order not to prematurely compromise their effectiveness and at the same time improve patients’ outcomes. We reviewed the current literature on ceftazidime/avibactam, meropenem/vaborbactam and cefiderocol, focusing on antimicrobial spectrum, on the prevalence and mechanisms of resistance development and on the main in vitro and clinical experiences available so far. Subsequently, we performed a step-by-step construction of a speculative algorithm for a reasoned prescription of these new antibiotics, contemplating both empirical and targeted use. Attention was specifically posed on patients with life-risk conditions and in settings with elevated prevalence of MDRO.

Predictive Performance of Risk Factors for Multidrug-Resistant Pathogens in Nosocomial Pneumonia

Rationale: In 2017, the International European Respiratory Society/European Society of Intensive Care Medicine/European Society of Clinical Microbiology and Infectious Diseases/Latin American Thoracic Society (European) guidelines defined new risk factors for multidrug-resistant (MDR) pathogens in patients with nosocomial pneumonia.Objectives: To assess the predictive performance of these newly defined risk factors for MDR pathogens.Methods: We enrolled 507 adult patients with nosocomial pneumonia who were treated in six intensive care units at the Hospital Clinic of Barcelona in Spain. Of the 503 patients at high MDR pathogen and mortality risk, 275 (54%) had no septic shock and 228 (46%) had septic shock.Results: Admission to hospital settings with high rates of MDR pathogens (n = 421; 83%) and prior antibiotic use (n = 399; 79%) showed the highest prevalence in the overall population, with sensitivities of 92% and 85% and negative predictive values of 85% and 82%, respectively. However, low specificities and low positive predictive values were found. Previous respiratory MDR pathogen isolation was less common (n = 17; 3%) but presented a specificity and positive predictive value of 100%. The area under the receiver operating characteristic curve was less than 0.6 for all risk factors and combinations.Conclusions: The risk factors proposed by the European Respiratory Society/European Society of Intensive Care Medicine/European Society of Clinical Microbiology and Infectious Diseases/Latin American Thoracic Society showed low accuracy for predicting MDR pathogens in intensive care unit acquired pneumonia (ICU-AP). Admission to hospital settings with high rates of MDR pathogens and prior antibiotic use were the most prevalent risk factors, with a high sensitivity for predicting these microorganisms; prior positive cultures for MDR pathogens showed high specificity but very low sensitivity. Combinations of risk factors did not show any great accuracy for predicting these microorganisms. Further studies assessing combined strategies of risk stratification and complementary methods are now warranted.

Spectroscopic and chromatographic identification of bioprospecting bioactive compounds from cow feces: Antimicrobial and antioxidant activities evaluation of gut bacterium Pseudomonas aeruginosa KD155

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Isolation and screening of P. aeruginosa from cow dung having antagonistic potential.

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Molecular characterization of the isolate and thermodynamic stability study.

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Antimicrobial activity of extracellular crude extract of P. aeruginosa against microorganisms of medical importance.

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Antioxidant activity of extracellular crude extracts using DPPH scavenging activity.

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Isolation and characterisation of bioactive compound using HP-TLC, FTIR and GC-MS.

The prime objective of our study was to evaluate antimicrobial and antioxidant activities of Pseudomonas aeruginosa KD155 isolated from cow dung. For identification of the isolate KD155, molecular techniques were employed and obtained 16S rRNA gene sequence was deposited in the NCBI GenBank under the accession number MK801234. Extracellular crude extract of P. aeruginosa KD155 displayed significant antimicrobial activity against Bacillus subtilis (MTCC 441) and Staphylococcus aureus (MTCC 7443) in comparison to tetracycline and ketoconazole. The resistance of extracellular crude chloroform extract to DPPH scavenging activity was also observed with 77.49% inhibition rate reflecting strong antioxidant activity. In addition, HP-TLC, FT-IR and GC-MS analysis of extracellular chloroform crude extract was done which revealed phenolic compound (quercetin) as major bioactive metabolite being produced by our isolate KD155. Further, the stability of 16S rRNA sequence of the strain was studied using bioinformatics tools viz. mfold and NEB cutter indicating the thermodynamic stability of its gene sequence.

Relationship between the composition of the intestinal microbiota and the tracheal and intestinal colonization by opportunistic pathogens in intensive care patients

Objective

Infections caused by multidrug-resistant Gram-negative bacilli (MDR-GNB) are a major issue in intensive care. The intestinal and oropharyngeal microbiota being the reservoir of MDR-GNB. Our main objective was to assess the link between the composition of the intestinal microbiota and the tracheal and intestinal colonization by MDR-GNB, and also by Enterococcus spp. and yeasts.

Methods

We performed a 2-month prospective, monocentric cohort study in the medical intensive care unit of our hospital. Patients ventilated >3 days and spontaneously passing feces were included. A fecal sample and an endotracheal aspiration (EA) were collected twice a week. MDR-GNB but also Enterococcus faecium and yeasts (as potential dysbiosis surrogate markers) were detected by culture methods. The composition of the intestinal microbiota was assessed by 16S profiling.

Results

We collected 62 couples of feces and EA from 31 patients, including 18 feces and 9 EA positive for MDR-GNB. Forty-eight fecal samples were considered for 16S profiling. We did not observe a link between the diversity and the richness of the intestinal microbiota and the MDR-GNB intestinal relative abundance (RA). Conversely, we observed a negative link between the intestinal diversity and richness and the RA of Enterococcus spp. (p<0.001).

Conclusion

The fecal MDR-GNB RA was not associated to the diversity nor the richness of the intestinal microbiota, but that of Enterococcus spp. was.

Clinical study on the safety and efficacy of high-dose tigecycline in the elderly patients with multidrug-resistant bacterial infections: A retrospective analysis

Multidrug-resistant bacterial (MDRB) infections have been difficult to treat clinically. Tigecycline (TIG) has several advantages, especially in the treatment of severe infections. Many clinicians have considered increasing the TIG dose to improve the efficacy of this molecule. The safety and efficacy of high-dose TIG in elderly patients with MDRB infections were investigated in this study.We conducted a retrospective analysis of the elderly patients with MDRB infections who were treated at the First Affiliated Hospital. A total of 106 patients received a conventional dose (CD-TIG group: 50 mg every 12 hours) of TIG and 51 received a high dose (HD-TIG group: 100 mg every 12 hours). The data from all patients were collected for examining the clinical features and performing the microbiological analysis. The safety profile and efficacy of the HD regimen were investigated.The clinical efficacy and microbiological eradication in the patients with MDRB infection were higher in the HD-TIG group than the CD-TIG group. The independent predictors of clinical cure were the use of TIG at HD (odd ratio [OR], 5.129; 95% confidence interval [CI] [1.890, 13.921]; P = .001) and microbiological eradication (OR, 3.049; 95% CI, [1.251, 7.430]; P = .014). In the ventilator-associated pneumonia (VAP) and bloodstream infection (BSI) subgroups, the sole independent predictor of clinical cure was the HD of TIG, and no significant adverse events were observed. The occurrence of multidrug-resistant Acinetobacter baumannii infection and an MIC value of 1 to 2 g/mL for TIG were independently associated with clinical failure in the VAP subgroup.HDs of TIG was found to associate with better clinical efficacy and microbiological eradication than its CDs in the elderly patients with MDRB infections. In the VAP and BSIs subgroups, administration of HDs of TIG was associated with better outcomes.

Activity of Meropenem-Vaborbactam against Bacterial Isolates Causing Pneumonia in Patients in U.S. Hospitals during 2014 to 2018

Meropenem-vaborbactam is approved to treat hospital-acquired pneumonia (HAP), including ventilator-associated pneumonia (VAP), in Europe. Meropenem-vaborbactam activity was evaluated against 3,193 Pseudomonas aeruginosa and 4,790 Enterobacterales isolates causing pneumonia, including VAP, in hospitalized patients in the United States. Susceptibility testing was performed by using the broth microdilution method, and all carbapenem-resistant isolates were submitted for whole-genome sequencing.

Meropenem-vaborbactam is approved to treat hospital-acquired pneumonia (HAP), including ventilator-associated pneumonia (VAP), in Europe. Meropenem-vaborbactam activity was evaluated against 3,193 Pseudomonas aeruginosa and 4,790 Enterobacterales isolates causing pneumonia, including VAP, in hospitalized patients in the United States. Susceptibility testing was performed by using the broth microdilution method, and all carbapenem-resistant isolates were submitted for whole-genome sequencing. Meropenem-vaborbactam exhibited almost complete activity against Enterobacterales (>99.9% susceptible), including carbapenem-resistant Enterobacterales (CRE), and was also very active against P. aeruginosa isolates (89.5% susceptible).

Risk stratification and treatment of ICU-acquired pneumonia caused by multidrug- resistant/extensively drug-resistant/pandrug-resistant bacteria

PURPOSE OF REVIEW

Describe the risk factors and discuss the management of multidrug-resistant (MDR) bacteria responsible for pneumonia among critically ill patients, including methicillin-resistant Staphylococcus aureus, extended spectrum beta-lactamase-producing Enterobactericeae, carbapenem-resistant Enterobactericeae, multidrug resistant Pseudomonas aeruginosa, and Acinetobacter baumannii.

RECENT FINDINGS

Multiple factors have been associated with infections because of MDR bacteria, including prolonged hospital stay, presence of invasive devices, mechanical ventilation, colonization with resistant pathogens, and use of broad-spectrum antibiotics. Management of these infections includes the prompt use of appropriate antimicrobial therapy, implementation of antimicrobial stewardship protocols, and targeted active microbiology surveillance. Combination therapy and novel molecules have been used for the treatment of severe infections caused by resistant bacteria.

SUMMARY

The exponential increase of antimicrobial resistance among virulent pathogens currently represents one of the main challenges for clinicians in the intensive care unit. Knowledge of the local epidemiology, patient risk stratification, and infection-control policies remain key elements for the management of MDR infections. Results from clinical trials on new molecules are largely awaited.

Differences in Colistin Administration and Bacterial and Treatment Outcomes in Critically Ill Patients

The desired target steady-state average colistin concentration (C_ss,avg) to balance between therapeutic effectiveness and nephrotoxicity is largely unclear. The objective of this study was to evaluate the effect of the desired target colistin C_ss,avg on the effectiveness and safety of IV colistin therapy in critically ill patients. Overall, 153 critically ill patients (71% males) receiving IV colistin were retrospectively analyzed. The desired target colistin C_ss,avg was estimated based on the daily colistin dose and creatinine clearance of each patient. No significant predictor for clinical cure was identified. However, microbiological outcome was significantly associated with pneumonia compared to bacteremia (odds ratio [OR] 0.092, 95% confidence interval [CI] [0.033-0.251], P < 0.001) and the use of IV colistin loading dose (OR 2.783, 95% CI [1.126-6.880], P = 0.027). Colistin-associated nephrotoxicity was significantly less likely to occur in patients who received inhaled colistin close to the time of IV colistin therapy (OR 0.331, CI [0.119-0.925], P = 0.035). The desired target C_ss,avg of colistin was not associated with treatment outcomes or the risk of nephrotoxicity. Loading dose and inhaled colistin use near the time of IV colistin therapy may be considered to maximize therapeutic effectiveness and minimize the risk of colistin-associated nephrotoxicity, respectively.

In vitro study of antimicrobial activity on Klebsiella Pneumoniae biofilms in endotracheal tubes

Effective treatment approaches for biofilms in endotracheal tubes (ETTs) are lacking. In this study, we evaluated the in vitro effects of five antimicrobials against biofilms formed by Klebsiella pneumoniae in ETTs. K. pneumoniae was added to minimal mucin medium prior to inoculation in microtiter plates containing ETT fragments. Biofilm susceptibility was assessed by crystal violet staining. At 24 h, the antimicrobials significantly reduced biofilm formation. At 48 h, all of the antimicrobial agents exhibited significant reductions in biofilm formation, even at concentrations above the minimum inhibitory concentration (MIC). Tigecycline and fosfomycin showed the greatest inhibition capacity, with good activity at concentrations twofold greater than the MIC. K. pneumoniae exhibited excellent biofilm formation ability, with formation in the first 24 h and significantly reduced antimicrobial activity. These results contribute to the establishment of new antibiotic breakpoints for the adequate management of infections associated with biofilm formation. Abbreviations ETT Endotracheal tube MIC Minimum inhibitory concentration MBIC Minimum biofilm inhibitory concentration OD Optical density PBS Phosphate-buffered saline VAP Ventilator-associated pneumonia.

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.

Adverse events of high-dose tigecycline in the treatment of ventilator-associated pneumonia due to multidrug-resistant pathogens

The off-label uses of tigecycline (TGC) to treat ventilator-associated pneumonia (VAP) have aroused worldwide concerns. The efficacy about TGC has been recently reported. However, the adverse events (AEs) remain controversial. Our study aims to analyze the safety of the high-dose (HD) regimens in the treatment of VAP due to multidrug-resistant (MDR) pathogens.The clinical data of 134 patients who were diagnosed with VAP from January 2013 to December 2015 in the NeuroScience Care Unit (NCU) were analyzed retrospectively. The incidence and the occurrence time of AEs, 28-day mortality, and the factors of clinical effectiveness were explored.A total of 54 patients received the standard dose group (SD), 69 in the HD, and 11 in the nonstandard HD group (NHD). Acinetobacter baumannii were the main pathogenic bacteria. There was no statistic difference in the incidence of AEs and the 28-day mortality among the 3 groups (P > .05). Total bilirubin (TBIL) increased significantly after SD of TGC treatment (P = .004). Liver dysfunction occurred the latest (10.83 ± 7.08), not in the duration of HD group (9.63 ± 3.92), whereas in the SD group (13.00 ± 7.57) and NHD group (12.64 ± 3.70). Patients with septic shock, MODS, and higher APACHE II score were of high risk in mortality. The HD group was associated with higher clinical effective rate and bacteria clearance rate.HD TGC was relatively safe and tolerable in ICU patients. The risk of side effects was related to the TGC duration, although not increased as the dosage rose. Full course of the HD regimen was associated with better outcomes for the treatment of VAP patients, especially for the MDR gram-negative bacilli infection. Inappropriate antimicrobial treatment might lead to clinical treatment failure.

Multidrug and co-resistance patterns of non-fermenting Gram-negative bacilli involved in ventilator-associated pneumonia carrying class 1 integron in the North of Iran

INTRODUCTION

Ventilator-associated pneumonia (VAP) due to non-fermenting Gram-negative bacilli (NFGNB), especially Pseudomonas aeruginosa and Acinetobacter spp., is one of the main hospital-acquired infections leading to mortality and morbidity, especially in intensive care units (ICUs). This study seeks to determine the multidrug and co-resistance (MDR) patterns of NFGNB that are agents of VAP, and assess the presence of class 1 integron in these bacteria.

METHODS

This cross-sectional study involved VAP patients admitted in the ICUs of 18 hospitals in the Mazandaran province, located in the North of Iran. The antibiotic susceptibility pattern was determined by the minimum inhibitory concentration (MIC) test by using broth microdilution method. Presence of class 1 integron was evaluated by the polymerase chain reaction (PCR) assay.

RESULTS

Out of a total of 83 patients who were microbiologically diagnosed as VAP, 52 non-duplicated NFGNBs (24 P. aeruginosa and 28 A. baumannii) were causative of VAP, out of which MDR NFGNBs were responsible for 48 (57.83%) cases. The frequencies of MDR NFGNBs were as follows: 27 (56.25%) A. baumannii and 21 (43.75%) P. aeruginosa. P. aeruginosa isolates were resistant to all aminoglycoside antibiotics (50%), ciprofloxacin (45.8%), ceftazidime (70.8%), cefepime (87.5%), colistin (62.5%), and imipenem (29.2%). A. baumannii isolates were resistant to aminoglycosides (53.6%), ciprofloxacin (85.7%), ceftazidime (92. 9%), cefepime (92.9%), colistin (35.7%), and imipenem (57.1%). Twelve isolates were resistant to all 10 tested antibiotics. The number of rates of class 1 integron, positive for MDR P. aeruginosa and MDR A. baumannii, were 20 (95.23%) and 21 (77.78%), respectively.

CONCLUSION

The high prevalence of multidrug resistance and incidence of class 1 integron is a therapeutic concern. Employing antibiotic stewardship in hospitals could prevent the dissemination of MDR bacteria.

Determination of tigecycline in human plasma by LC-MS/MS and its application to population pharmacokinetics study in Chinese patients with hospital-acquired pneumonia

A selective, sensitive and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of tigecycline (TGC) in human plasma, using tigecycline-d₉ as an internal standard (IS). Analytical samples were prepared using a protein precipitation method coupled with a concentration process. The analyte and IS were separated on a reversed-phase Waters Acquity UPLC^® BEH-C₁₈ column (2.1 × 50 mm i.d., 1.7 μm) with a flow rate of 0.25 mL/min. The mobile phase consisted of water, containing 0.2% formic acid (v/v) with 10 mm ammonium formate (A) and acetonitrile (B). The mass spectrometer was operated in selected reaction monitoring mode through electrospray ionization ion mode using the transitions of m/z 586.2 → 513.1 and m/z 595.1 → 514.0 for TGC and IS, respectively. The linearity of the method was in the range of 10-5000 ng/mL. Intra- and inter-batch precision (CV) for TGC was <9.27%, and the accuracy ranged from 90.06 to 107.13%. This method was successfully applied to the analysis of samples from hospital-acquired pneumonia patients treated with TGC, and a validated population pharmacokinetic model was established. This developed method could be useful to predict pharmacokinetics parameters and valuable for further pharmacokinetics/pharmacodynamics studies.

Ventilator-Associated Pneumonia: The Role of Emerging Diagnostic Technologies

Antibiotic resistance has emerged as a key determinant of outcome in patients with serious infections along with the virulence of the underlying pathogen. Within the intensive care unit (ICU) setting, ventilator-associated pneumonia (VAP) is a common nosocomial infection that is frequently caused by multidrug-resistant bacteria. Antimicrobial resistance is a growing challenge in the care of critically ill patients. Escalating rates of antibiotic resistance add substantially to the morbidity, mortality, and cost related to infection in the ICU. Both gram-positive organisms, such as methicillin-resistant Staphylococcus aureus and vancomycin-intermediate S. aureus, and gram-negative bacteria, including Pseudomonas aeruginosa, Acinetobacter species, carbapenem-resistant Enterobacteriaceae, such as the Klebsiella pneumoniae carbapenemase-producing bacteria, and extended spectrum β-lactamase organisms, have contributed to the escalating rates of resistance seen in VAP and other nosocomial infections. The rising rates of antimicrobial resistance have led to the routine empiric administration of broad-spectrum antibiotics even when bacterial infection is not documented. Moreover, there are several new broader-spectrum antibiotics that have recently become available and others scheduled for approval in the near future. The challenge to ICU clinicians is how to most effectively utilize these agents to maximize patient benefits while minimizing further emergence of resistance. Use of rapid diagnostics may hold the key for achieving this important balance. There is an urgent need for integrating the administration of new and existing antibiotics with the emerging rapid diagnostic technologies in a way that is both cost-effective and sustainable for the long run.

Antibacterial activity of six medicinal Cameroonian plants against Gram-positive and Gram-negative multidrug resistant phenotypes

Background

Infectious diseases due to multidrug-resistant bacteria are one of the causes of treatment failures contributing to an increase in mortality and/or morbidity. In this study, we evaluated the antibacterial potential of different parts of six medicinal plants namely Alstonia boonei, Ageratum conyzoides, Croton macrostachys, Cassia obtusifolia, Catharanthus roseus and Paullinia pinnata against a panel of 36 multi-drug resistant (MDR) Gram-negative and Gram-positive bacteria.

Methods

Minimum Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) of the methanol extracts from different parts of the plants were determined using broth microdilution method; standard phytochemical methods were used for phytochemical screening.

Results

Several phytochemical classes such as polyphenols, sterols, triterpenes, alkaloids, flavonoids and saponins were identified in the plant extracts. MIC values obtained ranged from 64 to 1024 μg/mL. Leaves extract of Catharanthus roseus (86.11 %), Croton macrostachys (83.33 %) and Paullinia pinnata (80.55 %) displayed the best antibacterial spectra. The lowest MIC value of 64 μg/mL was obtained with the Paullinia pinnata stems extract and Cassia obtusifolia extract against the strain of Staphylococcus aureus MRSA8. Results also showed that the tested samples generally displayed bacteriostatic effects with MBC values obtained in only 3.35 % of the cases where plant extracts were active.

Conclusion

The results obtained at the end of this study demonstrate for the first time the antibacterial activity of the studied medicinal plants against MDR bacteria. The tested plants could be a reservoir of molecules to fight against MDR bacterial infections.

Clinical epidemiology, treatment and prognostic factors of extensively drug-resistant Acinetobacter baumannii ventilator-associated pneumonia in critically ill patients

Limited data exist regarding prognostic factors and optimal antimicrobial treatment of infections caused by extensively drug-resistant Acinetobacter baumannii (XDR-AB). This retrospective cohort study included 93 adult patients who developed ventilator-associated pneumonia (VAP) due to XDR-AB in the ICU of the University Hospital of Heraklion, Greece, from October 2012 to April 2015. XDR-AB isolates were mainly susceptible to colistin (93.5%) and tigecycline (25.8%), whereas 6 (6.5%) were pandrug-resistant. Prior to infection, patients had long durations of mechanical ventilation and hospital stay and multiple exposures to antibiotics. Median Charlson co-morbidity and APACHE II scores were 2 and 17, respectively. Mortality at 28 days of infection onset was high (34.4%) despite high rates of in-vitro-active empirical (81.7%) and definitive (90.3%) treatment. Active colistin-based combination therapy (n = 55) and monotherapy (n = 29) groups had similar 28-day mortality (27.6% vs. 30.9%, respectively) and Kaplan-Meier survival estimates over time. In multivariable Cox regression, advanced age (aHR = 1.05 per year increase, 95% CI 1.02-1.09), rapidly fatal underlying disease (aHR = 2.64, 95% CI 0.98-9.17) and APACHE II score (aHR = 1.06 per unit increase, 95% CI 0.99-1.14) were identified as independent predictors of 28-day mortality, but no difference in mortality hazards between the active colistin-based combination therapy and monotherapy groups was produced (aHR = 0.88, 95% CI 0.35-2.38). These results support the use of colistin as a first-line agent against VAP in settings where XDR-AB is endemic, but oppose the introduction of colistin-based combination therapy as standard treatment.

Efficacy and Safety of Tigecycline for Patients with Hospital-Acquired Pneumonia

BACKGROUND

Tigecycline is an antibiotic agent with a broad spectrum, which has an antibacterial effect against many multidrug-resistant organisms. However, its clinical efficacy in the treatment of hospital-acquired pneumonia (HAP) is disputed.

MATERIALS AND METHODS

In this report, a systematic review and meta-analysis were conducted to evaluate the efficacy and safety of tigecycline for the treatment of HAP. The primary outcome was the rate of clinical cure, and the secondary outcomes were mortality and adverse events (AEs).

RESULTS

Four trials involving 1,234 patients were included. The standard-dose tigecycline and comparator groups did not differ significantly in their rates of clinical cure. However, high-dose tigecycline was more effective than standard-dose tigecycline or the comparators for the treatment of HAP. There was no significant difference in mortality between the standard-dose or high-dose regimen and the comparators. Although the safety profile of standard-dose tigecycline was similar to the comparators, the high-dose regimen exhibited more AEs compared with the other groups.

CONCLUSION

High-dose tigecycline is efficient for the treatment of HAP but is associated with more AEs.

Pseudomonas aeruginosa ventilator-associated pneumonia management

Ventilator-associated pneumonia is the most common infection in intensive care unit patients associated with high morbidity rates and elevated economic costs; Pseudomonas aeruginosa is one of the most frequent bacteria linked with this entity, with a high attributable mortality despite adequate treatment that is increased in the presence of multiresistant strains, a situation that is becoming more common in intensive care units. In this manuscript, we review the current management of ventilator-associated pneumonia due to P. aeruginosa, the most recent antipseudomonal agents, and new adjunctive therapies that are shifting the way we treat these infections. We support early initiation of broad-spectrum antipseudomonal antibiotics in present, followed by culture-guided monotherapy de-escalation when susceptibilities are available. Future management should be directed at blocking virulence; the role of alternative strategies such as new antibiotics, nebulized treatments, and vaccines is promising.

Antibiotic regimens for treatment of infections due to multidrug-resistant Gram-negative pathogens: An evidence-based literature review

Evidences regarding the efficacy of different antibiotic regimens proposed for treatment of multidrug-resistant (MDR) Gram-negative pathogens have been reviewed. Available data in Scopus, Medline, EMBASE, the Cochrane central register of controlled trials, and Cochrane database of systematic reviews have been collected. Several antibiotic regimens are proposed for treatment of MDR Gram-negative infections (defined as nonsusceptibility to at least one agent in three or more antimicrobial categories). The most challenging issue is the treatment of carbapenem-resistant (CR) Gram-negative pathogens. A carbapenem plus either colistin or tigecycline was the most effective regimen for treatment of CR Gram-negative pathogens with low-level resistance (minimal inhibitory concentration [MIC] ≤ 8 mg/L). However, in high-level resistance (MIC > 8 mg/L), combination of colistin and tigecycline showed promising effect.

Risk factors for ventilator-associated pneumonia in patients with severe traumatic brain injury in a Serbian trauma centre

INTRODUCTION

The aims of this study were (1) to assess the incidence of ventilator-associated pneumonia (VAP) in patients with traumatic brain injury (TBI), (2) to identify risk factors for developing VAP, and (3) to assess the prevalence of the pathogens responsible.

PATIENTS AND METHODS

The following data were collected prospectively from patients admitted to a 24-bed intensive care unit (ICU) during 2013/14: the mechanism of injury, trauma distribution by system, the Acute Physiology and Chronic Health Evaluation (APACHE) II score, the Abbreviated Injury Scale (AIS) score, the Injury Severity Score (ISS), underlying diseases, Glasgow Coma Scale (GCS) score, use of vasopressors, need for intubation or cardiopulmonary resuscitation upon admission, and presence of pulmonary contusions. All patients were managed with a standardized protocol if VAP was suspected. The Sequential Organ Failure Assessment (SOFA) score and the Clinical Pulmonary Infection Score (CPIS) were measured on the day of VAP diagnosis.

RESULTS

Of the 144 patients with TBI who underwent mechanical ventilation for >48h, 49.3% did not develop VAP, 24.3% developed early-onset VAP, and 26.4% developed late-onset VAP. Factors independently associated with early-onset VAP included thoracic injury (odds ratio (OR) 8.56, 95% confidence interval (CI) 2.05-35.70; p=0.003), ISS (OR 1.09, 95% CI 1.03-1.15; p=0.002), and coma upon admission (OR 13.40, 95% CI 3.12-57.66; p<0.001). Age (OR 1.04, 95% CI 1.02-1.07; p=0.002), ISS (OR 1.09, 95% CI 1.04-1.13; p<0.001), and coma upon admission (OR 3.84, 95% CI 1.44-10.28; p=0.007) were independently associated with late-onset VAP (Nagelkerke r(2)=0.371, area under the curve (AUC) 0.815, 95% CI 0.733-0.897; p<0.001). The 28-day survival rate was 69% in the non-VAP group, 45.7% in the early-onset VAP group, and 31.6% in the late-onset VAP group. Acinetobacter spp was the most common pathogen in patients with early- and late-onset VAP.

CONCLUSIONS

These results suggest that the extent of TBI and trauma of other organs influences the development of early VAP, while the extent of TBI and age influences the development of late VAP. Patients with early- and late-onset VAP harboured the same pathogens.

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.