Update on management options in the treatment of nosocomial and ventilator assisted pneumonia: review of actual guidelines and economic aspects of therapy

The Impact of Fosfomycin on Gram Negative Infections: A Comprehensive Review

Multidrug-resistant or extended drug resistance has created havoc when it comes to patient treatment, as options are limited because of the spread of pathogens that are extensively or multidrug-resistant (MDR or XDR) and the absence of novel antibiotics that are effective against these pathogens. Physicians have therefore started using more established antibiotics such as polymyxins, tetracyclines, and aminoglycosides. Fosfomycin has just come to light as a result of the emergence of resistance to these medications since it continues to be effective against MDR and XDR bacteria that are both gram-positive and gram-negative. Fosfomycin, a bactericidal analogue of phosphoenolpyruvate that was formerly utilised as an oral medication for uncomplicated urinary tract infections, has recently attracted the interest of clinicians around the world. It may generally be a suitable therapy option for patients with highly resistant pathogenic infections, according to the advanced resistance shown by gram-negative bacteria. This review article aims to comprehensively evaluate the impact of fosfomycin on gram negative infections, highlighting its mechanism of action, pharmacokinetics, clinical efficacy, and resistance patterns.

Estimation of Additional Costs in Patients with Ventilator-Associated Pneumonia

Healthcare-associated infections (HAIs) present a global public health challenge, contributing to high morbidity and mortality and substantial economic burdens. Ventilator-associated pneumonia (VAP) ranks as the second most prevalent HAI in intensive care units (ICUs), emphasizing the need for economic analyses in this context. This retrospective cohort study, conducted at the General Hospital of Alicante from 2012 to 2019, aimed to assess additional costs related to VAP by comparing the extended length of stay for infected and non-infected ICU patients undergoing mechanical ventilation (MV) for more than 48 h. Employing propensity score association, 434 VAP patients were compared to an equal number without VAP. The findings indicate a significantly longer mechanical ventilation period for VAP patients (17.40 vs. 8.93 days, p < 0.001), resulting in an extra 13.56 days of stay and an additional cost of EUR 20,965.28 per VAP episode. The study estimated a total cost of EUR 12,348,965.28 for VAP during the study period, underscoring the economic impact of VAP. These findings underscore the urgent need for rigorous infection surveillance, prevention, and control measures to enhance healthcare quality and reduce overall expenditures.

Risk Factors and Algorithms for the Empirical Treatment of Hospital-Acquired Pneumonia and Ventilator-Associated Pneumonia

Hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) continue to be major concerns for morbidity and mortality, especially in patients treated in the intensive care unit. With the rise in multidrug-resistant organisms, HAP and VAP treatment is challenged by the need for early appropriate treatment, with broad-spectrum agents, while still being aware of the principles of antibiotic stewardship. The two major society guidelines proposed a series of risk factors in their most recent guidelines to help identify patients who can most benefit from narrow- or broad-spectrum initial empiric antibiotic therapy. The guidelines reveal differences in the proposed risk factors and treatment approaches, as well as major similarities.

Emergence of Nosocomial Pneumonia Caused by Colistin-Resistant Escherichia coli in Patients Admitted to Chest Intensive Care Unit

(1) Background: Colistin is a last-resort antibiotic used in treating multidrug-resistant Gram-negative infections. The growing emergence of colistin resistance in Escherichia coli (E. coli) represents a serious health threat, particularly to intensive care unit (ICU) patients. (2) Methods: In this work, we investigated the emergence of colistin resistance in 140 nosocomial E. coli isolated from patients with pneumonia and admitted to the chest ICU over 36 months. Virulence and resistance-related genes and E. coli pathotypes in colistin-resistant and colistin-sensitive isolates were determined. (3) Results: Colistin resistance was observed in 21/140 (15%) of the nosocomial E. coli isolates. The MIC₅₀ of the resistant strains was 4 mg/L, while MIC₉₀ was 16 mg/L. Colistin-resistant isolates were also co-resistant to amoxicillin, amoxicillin/clavulanic, aztreonam, ciprofloxacin, and chloramphenicol. The mechanism of colistin resistance was represented by the presence of mcr-1 in all resistant strains. Respectively, 42.9% and 36.1% of colistin-resistant and colistin-sensitive groups were extended-spectrum β-lactamase (ESBL) producers, while 23.8% and 21% were metallo β-lactamase (MBL) producers. bla_TEM-type was the most frequently detected ESBL gene, while bla_IMP-type was the most common MBL in both groups. Importantly, most resistant strains showed a significantly high prevalence of astA (76.2%), aggR (76.2%), and pic (52.4%) virulence-related genes. Enteroaggregative E. coli (76%) was the most frequently detected genotype among the colistin-resistant strains. (4) Conclusion: The high colistin resistance rate observed in E. coli strains isolated from patients with nosocomial pneumonia in our university hospital is worrisome. These isolates carry different drug resistance and virulence-related genes. Our results indicate the need for careful monitoring of colistin resistance in our university hospital. Furthermore, infection control policies restricting the unnecessary use of extended-spectrum cephalosporins and carbapenems are necessary.

Comparing current US and European guidelines for nosocomial pneumonia

PURPOSE OF REVIEW

In the last 2 years, two major guidelines for the management of nosocomial pneumonia have been published: The International European Respiratory Society/European Society of Intensive Care Medicine/European Society of Clinical Microbiology and Infectious Diseases/Asociación Latinoamericana de Toráx guidelines for the management of hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) and the American guidelines for management of adults with HAP and VAP; both the guidelines made important clinical recommendations for the management of patients.

RECENT FINDINGS

With the increasing emergence of multidrug resistant (MDR) organisms, paired with a relative reduction in new antibiotic development, nosocomial infections have become one of the most significant issues affecting global healthcare today. Despite several stark differences between the European and American guidelines, they are in agreement about many aspects of nosocomial pneumonia management.

SUMMARY

American and European guidelines promote prompt and appropriate empiric treatment which is immediately guided by local microbiological data, followed by an adequate de-escalation protocol based on culture results with a 1-week course of treatment. Both also questioned the use of biomarkers in HAP/VAP, whether as part of the diagnosis or daily assessment of patients. On the contrary, they have conflicting views in regards to the optimum method of diagnosis, the risk factors used to stratify patients, the use of clinical scoring systems and the various antibiotic classes used. All were presented with varying levels of evidence to support these differences in opinion, indicating that further research into these areas is required before a consensus can be agreed upon.

Guanidine derivative inhibits C. albicans biofilm growth on denture liner without promote loss of materials' resistance

To reduce the burden of denture stomatitis and oral candidiasis, an aqueous solution containing polyhexamethylene guanidine hydrochloride (PHMGH) was investigated as an antifungal disinfectant against the leading cause of these oral conditions, Candida albicans. The solutions formulated with concentrations ranging from 0.125 to 0.50 wt% enabled increasing disinfection at the initial 5min-contact with 72h-mature candida biofilms formed on denture liner specimens. After 10 min-contact, the solution at lower concentration has reached total fungal elimination. The results also indicated that the denture liners preserved their mechanical property after the maximum contact time with the solution at the highest tested concentration. The PHMGH aqueous solutions at 0.125 wt% could be applied to promote interim denture liner disinfection without promoting the loss of materials' mechanical property.

The association of cardiovascular failure with treatment for ventilator-associated lower respiratory tract infection

PURPOSE

Ventilator associated-lower respiratory tract infections (VA-LRTIs), either ventilator-associated pneumonia (VAP) or tracheobronchitis (VAT), accounts for most nosocomial infections in intensive care units (ICU) including. Our aim was to determine if appropriate antibiotic treatment in patients with VA-LRTI will effectively reduce mortality in patients who had cardiovascular failure.

METHODS

This was a pre-planned subanalysis of a large prospective cohort of mechanically ventilated patients for at least 48 h in eight countries in two continents. Patients with a modified Sequential Organ Failure Assessment (mSOFA) cardiovascular score of 4 (at the time of VA-LRTI diagnosis and needed be present for at least 12 h) were defined as having cardiovascular failure.

RESULTS

VA-LRTI occurred in 689 (23.2%) out of 2960 patients and 174 (25.3%) developed cardiovascular failure. Patients with cardiovascular failure had significantly higher ICU mortality than those without (58% vs. 26.8%; p < 0.001; OR 3.7; 95% CI 2.6-5.4). A propensity score analysis found that the presence of inappropriate antibiotic treatment was an independent risk factor for ICU mortality in patients without cardiovascular failure, but not in those with cardiovascular failure. When the propensity score analysis was conducted in patients with VA-LRTI, the use of appropriate antibiotic treatment conferred a survival benefit for patients without cardiovascular failure who had only VAP.

CONCLUSIONS

Patients with VA-LRTI and cardiovascular failure did not show an association to a higher ICU survival with appropriate antibiotic treatment. Additionally, we found that in patients without cardiovascular failure, appropriate antibiotic treatment conferred a survival benefit for patients only with VAP.

TRIAL REGISTRY

ClinicalTrials.gov, number NCT01791530.

New guidelines for hospital-acquired pneumonia/ventilator-associated pneumonia: USA vs. Europe

PURPOSE OF REVIEW

The International ERS/ESICM/ESCMID/ALAT guidelines for the management of hospital-acquired pneumonia and ventilator-associated pneumonia were published in 2017 whilst the American guidelines for Management of Adults With Hospital-acquired and Ventilator-associated Pneumonia were launched in 2016 by the Infectious Diseases Society of America/ATS. Both guidelines made updated recommendations based on the most recent evidence sharing not only some parallelisms but also important conceptual differences.

RECENT FINDINGS

Contemporary therapy for hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) emphasizes the importance of prompt and appropriate antimicrobial therapy. There is an implicit risk, when appropriate means broad spectrum, that liberal use of antimicrobial combinations will encourage the emergence of multidrug resistant (MDR), extensively drug-resistant (XDR) and pandrug-resistant bacteria (PDR) and generate untreatable infections, including carbapenemase resistant infections.

SUMMARY

American and European guidelines have many areas of common agreement such as limiting antibiotic duration. Both guidelines were in favour of a close clinical assessment. Neither recommended a regular use of biomarkers but only in specific circumstances such as dealing with MDR and treatment failure. Risk factor prediction for MDR differed and whilst American guidelines focus on organ failure, the European ones did it in local ecology and septic shock.

Fosfomycin in infections caused by multidrug-resistant Gram-negative pathogens

The alarming increase in antibiotic resistance rates reported for various pathogens has resulted in the use of alternative treatment policies. Given the fairly limited availability of new antimicrobial drugs, the reassessment of older antibiotics is now an interesting option. Fosfomycin, a bactericidal analog of phosphoenolpyruvate that has been previously been employed as an oral treatment for uncomplicated urinary tract infection, has recently raised interest among physicians worldwide. In general, the advanced resistance described in Gram-negative bacteria suggests that fosfomycin can be an appropriate treatment option for patients with highly resistant microbial infections. This review, which refers to key available data, focuses on the possibility of extending the use of fosfomycin beyond urinary tract infections and against multidrug-resistant Gram-negative bacteria.

Ventilator-Associated Pneumonia and Events in Pediatric Intensive Care: A Single Center Study

OBJECTIVES

Ventilator-associated pneumonia is the second most common nosocomial infection in pediatric intensive care. The Centers for Disease Control and Prevention recently issued diagnosis criteria for pediatric ventilator-associated pneumonia and for ventilator-associated events in adults. The objectives of this pediatric study were to determine the prevalence of ventilator-associated pneumonia using these new Centers for Disease Control and Prevention criteria, to describe the risk factors and management of ventilator-associated pneumonia, and to assess a simpler method to detect ventilator-associated pneumonia with ventilator-associated event in critically ill children.

DESIGN

Retrospective, observational, single-center.

SETTING

PICU in a tertiary-care university hospital.

PATIENTS

Consecutive critically ill children mechanically ventilated for greater than or equal to 48 hours between November 2013 and November 2015.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 304 patients mechanically ventilated for greater than or equal to 48 hours, 284 were included. Among them, 30 (10.6%) met clinical and radiologic Centers for Disease Control and Prevention criteria for ventilator-associated pneumonia, yielding an prevalence of 7/1,000 mechanical ventilation days. Median time from mechanical ventilation onset to ventilator-associated pneumonia diagnosis was 4 days. Semiquantitative culture of tracheal aspirates was the most common microbiological technique. Gram-negative bacteria were found in 60% of patients, with a predominance of Haemophilus influenzae and Pseudomonas aeruginosa. Antibiotic therapy complied with adult guidelines. Compared with patients without ventilator-associated pneumonia, those with ventilator-associated pneumonia had significantly longer median durations of mechanical ventilation (15 vs 6 d; p < 0.001) and PICU stay (19 vs 9 d; p < 0.001). By univariate analysis, risk factors for ventilator-associated pneumonia were younger age, reintubation, acute respiratory distress syndrome, and continuous enteral feeding. Among the 30 patients with ventilator-associated pneumonia, 17 met adult ventilator-associated event's criteria (sensitivity, 56%).

CONCLUSIONS

Ventilator-associated pneumonia is associated with longer times on mechanical ventilation and in the PICU. Using the ventilator-associated event criteria is of interest to rapidly screen for ventilator-associated pneumonia in children. However, sensitivity must be improved by adapting these criteria to children.

Feasibility of Antimicrobial Stewardship (AMS) in Critical Care Settings: A Multidisciplinary Approach Strategy

Antimicrobial resistance is escalating and triggers clinical decision-making challenges when treating infections in patients admitted to intensive care units (ICU). Antimicrobial stewardship (AMS) may help combat this problem, but it can be difficult to implement in critical care settings. The implementation of multidisciplinary AMS in ICUs could be more challenging than what is currently suggested in the literature. Our main goal was to analyze the reduction in duration of treatment (DOT) for the most commonly used antibacterial and antifungal agents during the first six months of 2014, and during the same period two years later (2016). A total of 426 and 424 patient encounters, respectively, were documented and collected from the intensive care unit's electronic patient record system. Daily multidisciplinary ward rounds were conducted for approximately 30⁻40 min, with the goal of optimizing antimicrobial therapy in order to analyze the feasibility of implementing AMS. The only antimicrobial agent which showed a significant reduction in the number of prescriptions and in the duration of treatment during the second audit was vancomycin, while linezolid showed an increase in the number of prescriptions with no significant prolongation of the duration of treatment. A trend of reduction was also seen in the DOT for co-amoxiclavulanate and in the number of prescriptions of anidulafungin without any corresponding increases being observed for other broad-spectrum anti-infective agents (p-values of 0.07 and 0.05, respectively).

Influence of different peritoneal dialysis fluids on the in vitro activity of fosfomycin against Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa

Peritonitis is still the main infectious complication among patients on peritoneal dialysis. For treatment of peritoneal dialysis-related peritonitis, the intraperitoneal administration of antibiotics admixed to peritoneal dialysis fluids (PDFs) should be preferred. However, the influence of diverse PDFs on the activity of frequently used antibiotics has been investigated insufficiently. Thus, the present study set out to investigate the in vitro activity of fosfomycin against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis, and Staphylococcus aureus in commercially available PDFs. Time-kill curves in four different PDFs (Dianeal®, Extraneal®, Nutrineal®, and Physioneal®) were performed over 24 h with two different concentrations of fosfomycin (150 and 400 mg/L) and without antibiotics as control. Cation-adjusted Mueller Hinton broth (CA-MHB) was used as a comparator solution. In blank PDFs, bacterial growth of each organism evaluated was reduced when compared to CA-MHB. For S. aureus in blank Physioneal®, a reduction under the limit of detection was observed within 24 h. The activity of fosfomycin was reduced in all PDFs when compared to CA-MHB except for P. aeruginosa in Nutrineal® where the activity of fosfomycin was increased when investigated at 400 mg/L. Against E.coli, bactericidal activity was demonstrated in Extraneal®, Nutrineal®, and Physioneal®. Fosfomycin resistance (MIC > 1024 mg/L) was observed for P. aeruginosa in CA-MHB at both concentrations and in Nutrineal® at 150 mg/L. Fosfomycin is active in PDFs particularly against the frequently isolated enterobacterium E. coli. The choice of the respective PDF considerably influences the microbiological outcome in vitro. Further studies are warranted to investigate the clinical relevance of these findings.

Influence of severity of traumatic brain injury at hospital admission on clinical outcomes

ABSTRACT Traumatic brain injury (TBI) is a public health problem with high mortality and socioeconomic repercussions. We aimed to investigate the influence of TBI severity on the length of mechanical ventilation (MV) stay and length of hospital stay and on the prevalence of tracheostomy, pneumonia, neurosurgery and death. This retrospective, observational study evaluated medical records of 67 patients with TBI admitted to Irmandade da Santa Casa de Misericórdia de São Paulo. Severity was determined according to the Glasgow Coma Scale (GCS): mild (13-15 points; 36 patients; 53.7%), moderate (9-12 points; 14 patients; 20.9%) or severe (3-8 points; 17 patients; 25.4%). Severe TBI patients had higher prevalence of tracheostomy, pneumonia and neurosurgery. No significant differences were observed between TBI severity, mortality and length of MV stay. However, TBI severity influenced the length of hospital stay. TBI severity at admission, evaluated according to the GCS, influenced the prevalence of tracheostomy, pneumonia, neurosurgery and was associated to prolonged hospital stay.

Compatibility of fosfomycin with different commercial peritoneal dialysis solutions

For treatment of peritoneal dialysis-related peritonitis, intraperitoneal administration of antibiotics remains the preferable route. For home-based therapy, patients are commonly supplied with peritoneal dialysis fluids already containing antimicrobial agents. The present study set out to investigate the compatibility of fosfomycin with different peritoneal dialysis fluids, namely, Extraneal^®, Nutrineal^®, Physioneal^® 1.36% and Physioneal^® 2.27%, under varying storage conditions. The peritoneal dialysis fluid bags including 4 g fosfomycin were stored over 14 days at refrigeration temperature (6°C) and room temperature (25°C) and over 24 h at body temperature (37°C). Drug concentrations over time were determined by using high-performance liquid chromatography coupled to a mass spectrometer. In addition, drug activity was assessed by a disk diffusion method, diluent stability by visual inspection and drug adsorption by comparison of the measured and calculated concentrations. Blank peritoneal dialysis fluids and deionized water were used as comparator solutions. Fosfomycin was stable in all peritoneal dialysis fluids and at each storage condition investigated over the whole study period. The remaining drug concentrations ranged between 94% and 104% of the respective initial concentrations. No significant drug adsorption was observed for any peritoneal dialysis fluid at any storage condition. No relevant reduction of antimicrobial activity was observed. Fosfomycin is compatible with Extraneal^®, Nutrineal^® and Physioneal^® for up to two weeks at refrigeration or room temperature and may be used for home-based therapy. No dose adjustment is needed due to adsorption or degradation.

The Relationship of Paranasal Sinus Opacification to Hospital-Acquired Pneumonia in the Neurologic Intensive Care Unit Patient

BACKGROUND

The association between intensive care unit (ICU) sinusitis and the development of lower airway infections remains unclear. The objective of this study was to determine the correlation between the development of radiographic sinus opacification and pneumonia in the neurologic ICU setting.

METHODS

A retrospective review of head computed tomography or magnetic resonance imaging of 612 patients admitted to the neurocritical care unit at a tertiary care center from April 2013 through April 2014 was performed. Paranasal sinus opacification was measured using Lund-Mackay scores (LMS). A diagnosis of pneumonia was determined by the ICU team from radiographic, laboratory, and pulmonary data. Exclusion criteria included a history of endonasal surgery, sinonasal malignancy, facial fractures, ICU admission less than 3 days, or inadequate imaging.

RESULTS

Worsening sinus opacification occurred in 42.6% of patients and pneumonia in 18.5% of patients during ICU admission. Of the patients who developed pneumonia, 71.7% also developed worsening sinus opacification (P < .001). In 80.2% of cases, the sinus opacification developed prior to the diagnosis of pneumonia. The mean highest LMS for patients who developed pneumonia was 4.24 compared to 1.99 in patients who did not develop pneumonia (P < .001). Sinus air-fluid levels or complete sinus opacification occurred in a larger proportion of patients who developed pneumonia (46.9% vs 19.4%, P < .001). Mortality rates for patients with no pneumonia or sinusitis, pneumonia only, sinusitis only, and sinusitis with pneumonia were 7.6%, 15.6%, 18.3%, and 25.9%, respectively (P < .001).

CONCLUSIONS

This study finds a strong relationship between worsening sinus opacification in the neurologic ICU patient to the development of hospital-acquired pneumonia and increased mortality.

Antimicrobial Activity of Ceftazidime-Avibactam against Gram-Negative Bacteria Isolated from Patients Hospitalized with Pneumonia in U.S. Medical Centers, 2011 to 2015

Bacterial isolates were collected from patients hospitalized with pneumonia (PHP), including ventilator-associated pneumonia (VAP), from 76 U.S. medical centers in 2011 to 2015. The Gram-negative organisms (n = 11,185, including 1,097 from VAP) were tested for susceptibility to ceftazidime-avibactam and comparators by the broth microdilution method. β-Lactamase-encoding genes were screened using a microarray-based assay on selected isolates. Pseudomonas aeruginosa and Klebsiella spp. were the most common Gram-negative bacteria isolated from PHP and VAP. Ceftazidime-avibactam was very active against P. aeruginosa (n = 3,402; MIC₅₀/MIC₉₀, 2 and 4 μg/ml; 96.6% susceptible), including isolates nonsusceptible to meropenem (86.3% susceptible to ceftazidime-avibactam), piperacillin-tazobactam (85.6% susceptible), or ceftazidime (80.6% susceptible). Ceftazidime-avibactam was also highly active against Enterobacteriaceae (MIC₅₀/MIC₉₀, 0.12 and 0.5 μg/ml; 99.9% susceptible), including carbapenem-resistant Enterobacteriaceae (CRE) (n = 189; MIC₅₀/MIC₉₀, 0.5 and 2 μg/ml; 98.0% susceptible) and multidrug-resistant (MDR) (n = 674; MIC₅₀/MIC₉₀, 0.25 and 1 μg/ml; 98.8% susceptible) and extensively drug-resistant (XDR) (n = 156; MIC₅₀/MIC₉₀, 0.5 and 2 μg/ml; 98.1% susceptible) Enterobacteriaceae isolates, as well as Klebsiella species isolates showing an extended-spectrum β-lactamase (ESBL) screening-positive phenotype (n = 433; MIC₅₀/MIC₉₀, 0.25 and 1 μg/ml; 99.5% susceptible). Among Enterobacter spp. (24.8% ceftazidime nonsusceptible), 99.8% of the isolates, including 99.4% of ceftazidime-nonsusceptible isolates, were susceptible to ceftazidime-avibactam. The most common β-lactamases detected among Klebsiella pneumoniae and E. coli isolates were K. pneumoniae carbapenemase (KPC)-like and CTX-M-15, respectively. Only 8 of 6,209 Enterobacteriaceae isolates (0.1%) were ceftazidime-avibactam nonsusceptible, three NDM-1-producing strains with ceftazidime-avibactam MIC values of >32 μg/ml and five isolates with ceftazidime-avibactam MIC values of 16 μg/ml and negative results for all β-lactamases tested. Susceptibility rates among isolates from VAP were generally similar or slightly higher than those from all PHP.

Treatment of MRSA pneumonia: Clinical and economic comparison of linezolid vs. vancomycin - a retrospective analysis of medical charts and re-imbursement data of real-life patient populations

Objectives: To supplement the data collected in randomized clinical trials, the present study in patients with methicillin resistant Staphylococcus aureus (MRSA) pneumonia was conducted to explore the clinical effectiveness of linezolid and vancomycin in a routine clinical setting. Further, the overall costs of the patients' stay in the intensive care unit (ICU) were compared. Methods: This was a retrospective analysis of medical and reimbursement data of adult patients who were treated for MRSA pneumonia with linezolid or vancomycin. Since the subjects were not randomly assigned to treatments, propensity score adjustment was applied to reduce a potential selection bias. Results: In total, 226 patients were included; 95 received linezolid and 131 received vancomycin as initial therapy for MRSA pneumonia. Switches to another antibiotic were observed in 4 patients (4.2%) receiving linezolid and in 23 patients (17.6%) receiving vancomycin (logistic regression analysis; odds ratio linezolid/vancomycin: 0.183; 95% confidence interval [CI]: 0.052-0.647; p<0.01). All-cause in-hospital mortality was also lower in patients receiving linezolid (22 patients [23.2%] vs. 54 patients [41.2%]) (logistic regression analysis; odds ratio linezolid/vancomycin: 0.351; 95% CI: 0.184-0.671; p<0.01). The analysis of the total costs of stay in ICU did not reveal any major differences between the two treatment groups (cost ratio linezolid/vancomycin: 1.29; 95% CI: 0.84-1.98; p=0.24). Conclusions: These findings confirm in a routine clinical setting that linezolid is a valuable therapeutic alternative to vancomycin for the treatment of MRSA pneumonia. However, prospective studies in real-life patient populations are warranted.

Polymicrobial Ventilator-Associated Pneumonia: Fighting In Vitro Candida albicans-Pseudomonas aeruginosa Biofilms with Antifungal-Antibacterial Combination Therapy

The polymicrobial nature of ventilator-associated pneumonia (VAP) is now evident, with mixed bacterial-fungal biofilms colonizing the VAP endotracheal tube (ETT) surface. The microbial interplay within this infection may contribute for enhanced pathogenesis and exert impact towards antimicrobial therapy. Consequently, the high mortality/morbidity rates associated to VAP and the worldwide increase in antibiotic resistance has promoted the search for novel therapeutic strategies to fight VAP polymicrobial infections. Under this scope, this work aimed to assess the activity of mono- vs combinational antimicrobial therapy using one antibiotic (Polymyxin B; PolyB) and one antifungal (Amphotericin B; AmB) agent against polymicrobial biofilms of Pseudomonas aeruginosa and Candida albicans. The action of isolated antimicrobials was firstly evaluated in single- and polymicrobial cultures, with AmB being more effective against C. albicans and PolyB against P. aeruginosa. Mixed planktonic cultures required equal or higher antimicrobial concentrations. In biofilms, only PolyB at relatively high concentrations could reduce P. aeruginosa in both monospecies and polymicrobial populations, with C. albicans displaying only punctual disturbances. PolyB and AmB exhibited a synergistic effect against P. aeruginosa and C. albicans mixed planktonic cultures, but only high doses (256 mg L^-1) of PolyB were able to eradicate polymicrobial biofilms, with P. aeruginosa showing loss of cultivability (but not viability) at 2 h post-treatment, whilst C. albicans only started to be inhibited after 14 h. In conclusion, combination therapy involving an antibiotic and an antifungal agent holds an attractive therapeutic option to treat severe bacterial-fungal polymicrobial infections. Nevertheless, optimization of antimicrobial doses and further clinical pharmacokinetics/pharmacodynamics and toxicodynamics studies underpinning the optimal use of these drugs are urgently required to improve therapy effectiveness and avoid reinfection.

Simplifying Piperacillin/Tazobactam Dosing: Pharmacodynamics of Utilizing Only 4.5 or 3.375 g Doses for Patients With Normal and Impaired Renal Function

OBJECTIVES

To evaluate the pharmacodynamic exposure of piperacillin/tazobactam across the renal function range using 4.5 or 3.375 g dosing regimens.

METHODS

A 5000-patient Monte Carlo simulation was conducted to determine the probability of achieving 50% free time above the minimum inhibitory concentration ( fT > MIC) for piperacillin. Proposed regimens, using solely 4.5 or 3.375 g strengths, were compared with regimens listed in piperacillin/tazobactam prescribing information over creatinine clearance (CrCl) ranges of 120 mL/min to hemodialysis. The probability of target attainment (PTA) at MICs ≤ 16 μg/mL was compared between proposed and standard regimens.

RESULTS

At CrCl 41 to 120 mL/min, prolonged infusions of 4.5 g (3 hours) and 3.375 g (4 hours) every 6 hours resulted in ≥95% PTA versus ≥76% for standard regimens (0.5 hour). At CrCl 20 to 40 mL/min, 4.5 and 3.375 g every 8 hours as prolonged infusions achieved slightly higher PTA (≥98%) versus standard regimens (≥93%). Similarly, PTA achieved with prolonged infusions of 4.5 and 3.375 g every 12 hours (≥93%) was comparable with those of standard regimens (≥91%) at CrCl 1 to 19 mL/min. In hemodialysis, 100% PTA was achieved with prolonged infusion regimens.

CONCLUSION

Piperacillin/tazobactam regimens designed around the 4.5 or 3.375 g dose and prolonged infusions provided similar or better PTA at MICs ≤ 16 μg/mL compared with standard regimens. These observations may support the stocking and use of a single piperacillin/tazobactam strength to simplify dosing.

Clinical predictors and microbiology of ventilator-associated pneumonia in the intensive care unit: a retrospective analysis in six Italian hospitals

The purpose of this study was to assess the main clinical predictors and microbiological features of ventilator-associated pneumonia (VAP) in the Intensive Care Unit (ICU) environment. This work is a retrospective analysis over one year from September 2010 to September 2011. Patients' risk factors, causes of admission, comorbidities and respiratory specimens collected in six Italian ICUs were reviewed. Incidence and case fatality rate of VAP were evaluated. After stratification for VAP development, univariate and multivariate analyses were performed to assess the impact of patients' conditions on the onset of this infection. A total of 1,647 ICU patients (pts) were considered. Overall, 115 patients (6.9 %) experienced at least one episode of VAP. The incidence rate for VAP was 5.82/1,000 pts-days, with a case fatality rate of 44.3 %. Multivariate analysis showed that admission for neurological disorders (aIRR 4.12, CI 1.24-13.68, p = 0.02) and emergency referral to ICU from other hospitals (aIRR 2.11, CI 1.03-4.31, p = 0.04) were associated with higher risk of VAP, whereas a tendency to a higher risk of infection was detected for admission due to respiratory disease, cardiac disease, trauma and for having obesity or renal failure. A total of 372 microbiological isolates from respiratory specimens were collected in VAP patients. The most common species were Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa, showing high resistance rates to carbapenems. Neurological disorders and emergency referral at the admission into the ICU are significantly associated with the onset of VAP. A high incidence of multi-drug resistant Gram- species was detected in the respiratory specimens.

Investigational drugs in phase I and phase II clincial trials for the treatment of hospital-acquired pneumonia

INTRODUCTION

Hospital acquired pneumonia (HAP) is one of the main infections acquired by patients during a stay in hospital. The main issue when dealing with patients with HAP and ventilator associated pneumonia (VAP) is the increasing role of multi-drug resistant organisms (MDROs).

AREAS COVERED

In this review the authors summarize the actual situation of MDROs as a cause of HAP and VAP. They also review the current treatment options stated in the most important international guidelines. Finally, they focus on the investigational drugs that have reached the phase III stage of development and the novel compounds that are being studied in phase I and II clinical trials.

EXPERT OPINION

Thanks to their excellent activity against MDROs, drugs in development for the treatment of HAP and VAP can significantly improve the therapeutic options available. In selected patients, the possibility to administer directed therapy with monoclonal antibodies to specific pathogens is an exciting strategy in the fight against widespread resistance.

Current and Future Considerations for the Treatment of Hospital-Acquired Pneumonia

Hospital-acquired pneumonia (HAP) and health-care-associated pneumonia (HCAP) are leading causes of death, morbidity, and resource utilization in hospitalized patients, and are associated with a broad range of Gram-positive and Gram-negative pathogens. Here, we discuss the different definitions of HAP and HCAP, review current guidelines regarding the treatment of these conditions, highlight the shortcomings of current therapeutic options, and discuss new antibiotic treatments. To optimize therapeutic outcomes in patients with HAP/HCAP, initial antimicrobial treatment must be appropriate and should be given as soon as possible; inappropriate or delayed therapy greatly increases morbidity and mortality. Selection of the most appropriate antimicrobial agent depends on the causative pathogen(s); initial broad-spectrum therapy is commonly recommended and should cover all pathogens that may be present. Treatment selection should also take into consideration the following factors: knowledge of underlying local risk factors for antimicrobial resistance, disease staging, and risk factors related to specific pathogens such as Pseudomonas aeruginosa, Acinetobacter spp., and methicillin-resistant Staphylococcus aureus (MRSA). Guidelines consistently emphasize the importance of treating HAP and HCAP with early and appropriate broad-spectrum antibiotics, and recent developments in this field have resulted in the availability of several additional treatment options. Telavancin shows potent activity against Gram-positive bacteria including MRSA and can be administered once daily; it was approved in the USA and European Union for the treatment of HAP after demonstrating non-inferiority to vancomycin. Ceftobiprole medocaril exhibits rapid antimicrobial activity against a broad range of both Gram-positive and Gram-negative pathogens, including MRSA. It was approved for the treatment of HAP (excluding ventilator-associated pneumonia) and community-acquired pneumonia in Europe in 2013. These new treatments may offer effective alternative therapeutic options for the management of HAP.

FUNDING

Basilea Pharmaceutica Ltd., Basel, Switzerland.

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.

[Ventilation as a trigger for organ dysfunction and sepsis]

Both in the intensive care setting and during surgery, mechanical ventilation plays an important role in the treatment of critically ill patients with lung injury, but also in lung healthy patients. Mechanical ventilation is noncurative and is accompanied by various severe side effects. It is hypothesized that multiorgan failure can be induced by mechanical ventilation. Furthermore, there is evidence to suggest cross-talk between lungs and other organs. In particular, the activation of specific cells and cell programs in peripheral organs is an important step on the way to multiorgan failure. In addition to bidirectional connection between the lung and brain, nonprotective ventilation leads to cell apoptosis in the kidney and intestine and leads to an increase of biomarkers for organ dysfunction. It is believed that both inflammation mediators and pro-apoptotic factors are responsible for organ dysfunction.

Biomarkers, diagnosis and management of sepsis-induced acute kidney injury: a narrative review

Sepsis is a leading cause of acute kidney injury in clinical practice. The diagnosis of sepsis-induced acute kidney injury requires the diagnosis of sepsis and subsequent occurrence of acute kidney injury. The current definition for acute kidney injury is based on Scr and urine output, which is limited by the delayed identification of such patients. Numerous novel biomarkers have been found to be up-regulated in kidney injury, among which cystatin C and neutrophil gelatinase-associated lipocalin are the most studied. In the management of sepsis-induced acute kidney injury, early goal directed therapy may be potentially useful, but requires further validation in large clinical trials. It is well known that fluid overload is harmful in septic patients with established acute kidney injury and should be avoided. Renal replacement therapy is the mainstay treatment for the severe form of sepsis-induced acute kidney injury. However, there is still no consensus on the definition of timing and dosing in clinical practice, and the optimal timing and dosing are still unknown.

A comparison of virulence patterns and in vivo fitness between hospital- and community-acquired methicillin-resistant Staphylococcus aureus related to the USA400 clone

Methicillin-resistant Staphylococcus aureus (MRSA) isolates genetically related to the CA-MRSA clone MW2/USA400 (ST1-SCCmecIV lineage) from the United States have emerged in hospitals in Rio de Janeiro and are associated with nosocomial bloodstream infections. To understand the virulence mechanisms involved in the adaptability of ST1 isolates as a hospital pathogen in Rio de Janeiro, we compared the virulence traits and fitness properties of the Brazilian isolates with those displayed by the CA-MRSA isolates from the United States. Similar to the USA400 from the United States, all the Brazilian isolates tested carried the genes encoding SEH and LukDE. In contrast, none of the Brazilian isolates carried the lukSF PVL, sea, sec, and sek genes. Competition experiments in mice demonstrated a significant increase in the fitness for the CA-MRSA isolates MW2 and USA400-0051 from the United States compared to other isolates. In the foreign body animal model, 83 % more North-American bacterial cells were recovered compared to the Brazilian ST1 isolates. Differences in gene expression of important virulence factors were detected. Transcription of rnaIII and psmα3 was increased about two-fold in the isolates from the United States, and sasG about two-fold in the Brazilian isolates. Thus, it is possible that the virulence attenuation observed among the Brazilian hospital isolates, associated with the acquisition of multiple resistant determinants, are consequences of microevolutionary events that contributed to the necessary fitness adjustment of this lineage, allowing a typically community-acquired MRSA (MW2/USA400) to emerge as a successful hospital pathogen (Brazilian ST1-SCCmecIV).

Microbiology, resistance patterns, and risk factors of mortality in ventilator-associated bacterial pneumonia in a Northern Thai tertiary-care university based general surgical intensive care unit

Background

Ventilator-associated pneumonia (VAP) occurrence, causative pathogens, and resistance patterns in surgical intensive care units (SICU) are different between Western and developing Asian countries. In Thailand, resistant organisms have progressively increased in the last decade. However, the evidence describing causes of VAP and its outcomes, especially secondary to resistant pathogens, in Asian developing countries’ SICUs is very limited. Therefore, the objective of this study was to describe the incidence, pathogen characteristics, and risk factors that impact mortality and patient survival following VAP in a tertiary Northern Thai SICU.

Methods

Between 2008 and 2012, VAP occurred in a total of 150 patients in Chiang Mai University’s general SICUs (6.3±2.8 cases per 1,000 mechanical ventilator days). The following clinical data were collected from 46 patients who died and 104 patients who survived: microbiologic results, susceptible patterns, and survival status at hospital discharge. Antimicrobial susceptibility patterns were classified as susceptible, multidrug resistant (MDR), extensively drug resistant (XDR), and pan-drug resistant (PDR). The hazard ratio (HR) was calculated for risk factor analysis.

Results

Regarding the microbiology, gram negative organisms were the major pathogens (n=142, 94.7%). The first three most common organisms were Acinetobacter baumannii (38.7% of all organisms, mortality 41.4%), Klebsiella pneumoniae (17.3%, mortality 30.8%), and Pseudomonas aeruginosa (16.7%, mortality 16%) respectively. The most common gram positive organism was Staphylococcus aureus (4.0%, mortality 50%). The median day of VAP occurrence were significantly different between the three groups (P<0.01): susceptible (day 4), MDR (day 5), and XDR (day 6.5). Only half of all VAP cases were caused by susceptible organisms. Antibiotic resistance was demonstrated by 49.3% of the gram negative organisms and 62.5% of the gram positive organisms. Extensive drug resistance was evident only in Acinetobacter baumannii (30.6%) and Pseudomonas aeruginosa (1.3%). No pan-drug resistance was found during surveillance. The significant HR risk factors were age (P=0.03), resistant organisms (P=0.04), XDR (P=0.02), and acute physiology and chronic health evaluation II score (<0.01). Acinetobacter baumannii (P=0.06) and intubation due to severe sepsis (P=0.08) demonstrated a trend toward a significant increase in the HR. On the other hand, there were significantly decreased HRs in trauma patients (P=0.01). Initial administration of appropriate antibiotic therapy had a tendency toward a significant decrease in the HR (P=0.08).

Conclusion

Gram negative organisms were the primary cause of bacterial VAP in Chiang Mai University’s general SICU. Resistant strains were present in half of all VAP cases and were associated with the day of VAP onset. Regarding risk factors, age, acute physiology, chronic health evaluation II score, resistant organisms (especially XDR), and being a non-trauma patient increased the risk of mortality.

[Nosocomial infections in intensive care units]

Nosocomial infections (NI) still have a high incidence in intensive care units (ICUs), and are becoming one of the most important problems in these units. It is well known that these infections are a major cause of morbidity and mortality in critically ill patients, and are associated with increases in the length of stay and excessive hospital costs. Based on the data from the ENVIN-UCI study, the rates and aetiology of the main nosocomial infections have been described, and include ventilator-associated pneumonia, urinary tract infection, and both primary and catheter related bloodstream infections, as well as the incidence of multidrug-resistant bacteria. A literature review on the impact of different nosocomial infections in critically ill patients is also presented. Infection control programs such as zero bacteraemia and pneumonia have been also analysed, and show a significant decrease in NI rates in ICUs.