Epidemiology of ICU-acquired pneumonia.

PURPOSE OF REVIEW: Review of the epidemiology of ICU-acquired pneumonia, including both ventilator-associated pneumonia (VAP) and hospital-acquired pneumonia (HAP) in nonventilated ICU patients, with critical review of the most recent literature in this setting. RECENT FINDINGS: The incidence of ICU-acquired pneumonia, mainly VAP has decrease significantly in recent years possibly due to the generalized implementation of preventive bundles. However, the exact incidence of VAP is difficult to establish due to the diagnostic limitations and the methods employed to report rates. Incidence rates greatly vary based on the studied populations. Data in the literature strongly support the relevance of intubation, not ventilatory support, in the development of HAP in ICU patients, but also that the incidence of HAP in nonintubated patients is not negligible. Despite the fact of a high crude mortality associated with the development of VAP, the overall attributable mortality of this complication was estimated in 13%, with higher mortality rates in surgical patients and those with mid-range severity scores at admission. Mortality is consistently greatest in patients with HAP who require intubation, slightly less in VAP, and least for nonventilated HAP. The economic burden of ICU acquired pneumonia, particularly VAP, is important. The increased costs are mainly related to the longer periods of ventilatory assistance and ICU and hospital stays required by these patients. However, the different impact of VAP on economic burden among countries is largely dependent on the different costs associated with heath care. SUMMARY: VAP has significant impact on mortality mainly in surgical patients and those with mid-range severity scores at admission. The economic burden on ICU-acquired pneumonia depends mainly on the increased length of stay of these patients.

[Effective management of an outbreak with multiresistent Klebsiella pneumoniae in a neurorehabilitation unit]. / Effektives Management eines Ausbruchs mit multiresistenten Klebsiella pneumoniae in der Neurorehabilitation.

BACKGROUND: In addition to acute care hospitals, rehabilitation centres are increasingly confronted with multi-resistant pathogens. Long durations of stay and intensive treatments impose special hygienic challenges. MATERIAL AND METHODS: We investigated an extended spectrum beta-lactamase-Klebsiella pneumoniae (ESBL-K. pneumoniae) outbreak in a neurorehabilitation centre. We defined confirmed cases as patients who stayed in the centre during the outbreak period and from whom ESBL-K. pneumoniae was isolated with the outbreak sequence type. Probable cases had an epidemiological link to at least one confirmed case but no isolate for typing. Next generation sequencing (NGS) was performed on 53 isolates from patients. Environmental sampling was performed. Systematic microbiological screening was implemented and ESBL-K. pneumoniae-positive patients were cohorted in a designated ward. RESULTS: We identified 30 confirmed and 6 probable cases. NGS revealed three genetic clusters: Cluster 1 - the outbreak cluster - with isolates of 30 cases (sequence type ST15), Cluster 2 with 7 patients (ST405) and Cluster 3 with 8 patients (ST414). In two patients, the outbreak strain developed further antibiotic resistance, one with colistin resistance and the other carbapenem resistance. The outbreak ceased after strict isolation measures. DISCUSSION: Epidemiology and NGS results paired with the effectiveness of cohorting suggest that transmission occurred mainly from person to person in this outbreak. There was an apparent association of the probability to acquire ESBL-K. pneumoniae and treatment intensity, whereas infection rate was related to morbidity. The identification of the outbreak clone and additional clusters plus the development of additional antibiotic resistance shows the relevance of NGS and highlights the need for timely and efficient outbreak management.

The clinical significance of pneumonia in patients with respiratory specimens harbouring multidrug-resistant Pseudomonas aeruginosa: a 5-year retrospective study following 5667 patients in four general ICUs.

Pseudomonas aeruginosa is the leading cause of pneumonia in intensive care units (ICUs), with multidrug-resistant (MDR) strains posing a serious threat. The aim of this study was to assess the clinical relevance of MDR Pseudomonas isolates in respiratory clinical specimens. A 5-year retrospective observational study in four medical-surgical ICUs from a referral hospital was carried out. Of 5667 adults admitted to the ICU, 69 had MDR-PA in respiratory samples: 31 were identified as having pneumonia (HAP/VAP): 21 ventilator-associated pneumonia (VAP) and ten hospital-acquired pneumonia (HAP). Twenty-one (67.7%) adults with MDR-PA HAP/VAP died after a median of 4 days (18 of the 21 deaths within 8 days), compared with one (2.6%) without pneumonia at day 8. In a Cox proportional regression model, MDR-PA pneumonia was an independent variable [adjusted hazard ratio (aHR) 5.92] associated with 30-day ICU mortality. Most strains (85.1%) were susceptible to amikacin and colistin. Resistance to beta-lactams (third-generation cephalosporins and piperacillin-tazobactam) ranged from 44.1% to 45.3%. Meropenem showed poor overall activity (MIC[50/90] 16/32 mg/dL), with 47.0% having a minimum inhibitory concentration (MIC) breakpoint >8 mg/L. Twenty-four (77.4%) HAP/VAP episodes received inappropriate empirical therapy. Although empirical combination therapy was associated with less inappropriate therapy than monotherapy (16.7% vs. 88.3%, p < 0.01), there was no difference in survival (30% vs. 33.3%, p = 0.8). Pneumonia was identified in one-third of adult ICU patients harbouring MDR-PA in respiratory clinical specimens. These patients have a 6-fold risk of (early) death compared to ventilator-associated tracheobronchitis (VAT) and respiratory colonisation. New antibiotics and adjuvant therapies are urgently needed to prevent and treat MDR-PA HAP/VAP.

Does ventilator-associated event surveillance detect ventilator-associated pneumonia in intensive care units? A systematic review and meta-analysis.

BACKGROUND: Ventilator-associated event (VAE) is a new surveillance paradigm for monitoring complications in mechanically ventilated patients in intensive care units (ICUs). The National Healthcare Safety Network replaced traditional ventilator-associated pneumonia (VAP) surveillance with VAE surveillance in 2013. The objective of this study was to assess the consistency between VAE surveillance and traditional VAP surveillance. METHODS: We systematically searched electronic reference databases for articles describing VAE and VAP in ICUs. Pooled VAE prevalence, pooled estimates (sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV)) of VAE for the detection of VAP, and pooled estimates (weighted mean difference (WMD) and odds ratio ([OR)) of risk factors for VAE compared to VAP were calculated. RESULTS: From 2191 screened titles, 18 articles met our inclusion criteria, representing 61,489 patients receiving mechanical ventilation at ICUs in eight countries. The pooled prevalence rates of ventilator-associated conditions (VAC), infection-related VAC (IVAC), possible VAP, probable VAP, and traditional VAP were 13.8 %, 6.4 %, 1.1 %, 0.9 %, and 11.9 %, respectively. Pooled sensitivity and PPV of each VAE type for VAP detection did not exceed 50 %, while pooled specificity and NPV exceeded 80 %. Compared with VAP, pooled ORs of in-hospital death were 1.49 for VAC and 1.76 for IVAC; pooled WMDs of hospital length of stay were -4.27 days for VAC and -5.86 days for IVAC; and pooled WMDs of ventilation duration were -2.79 days for VAC and -2.89 days for IVAC. CONCLUSIONS: VAE surveillance missed many cases of VAP, and the population characteristics identified by the two surveillance paradigms differed. VAE surveillance does not accurately detect cases of traditional VAP in ICUs.

Independent risk factors associated with hospital-acquired pneumonia in an adult ICU: 4-year prospective cohort study in a university reference hospital.

BACKGROUND: Hospital-acquired pneumonia (HP) is the most common infection in adult intensive care units (ICUs). To develop effective strategies to prevent it, we identified factors that independently increased the risk of contracting HP while admitted at an ICU. METHODS: We performed a prospective cohort study during 4 years in which we included all patients who had been admitted for at least 24 h to the ICU at a university reference hospital in Spain. We conducted a multivariable Cox regression analysis to obtain adjusted hazard ratios (HR). The dependent variable for patients with HP was duration of ICU stay prior to the onset of HP. For those without HP, the dependent variable was duration of stay between admission and discharge from the ICU. The independent variables were intrinsic characteristics of the patients already present at admission to the ICU and diagnostic or therapeutic procedures performed during admission. RESULTS: We studied 4427 patients, of which 233 (5.3%) developed HP while admitted to the ICU. The strongest independent risk factors associated with the occurrence of HP were mechanical ventilation (HR = 8.2; 95% CI = 3.6-18.9) and the use of a nasogastric tube (HR = 2.3; 95% CI = 1.6-3.3). The intrinsic risk factors that were part of the model were the presence of decreased level of consciousness upon admission (HR = 2.0; 95% CI = 1.5-2.7) and the APACHE II index (HR = 1.018; 95% CI = 1.002-1.035). CONCLUSIONS: Although severity of illness upon admission (APACHE II index) and decreased level of consciousness were relevant predisposing factors to contract HP in the ICU, the strongest association corresponded to extrinsic factors such as mechanical ventilation and use of a nasogastric tube. The fact that these are therapeutic interventions facilitates developing prevention and control measures that can contribute to reduce the risk for HP.

The impact of aerosolized mucolytic agents on the airflow resistance of bacterial filters used in mechanical ventilation.

BACKGROUND/PURPOSE: In order to reduce the contamination in the ventilator, bacterial filters were placed on the expiratory limb of a ventilator circuit. Aerosolized mucolytic agents may increase the resistance of the ventilator. The goal of this study is to determine the impact of aerosolized mucolytic agents on the pressure change during mechanical ventilation. METHODS: A lung model was investigated with mucolytic inhaled agents of 10% acetylcysteine and 2% hypertonic saline. The agents were administered using a jet nebulizer every 45 minutes for 15 minutes. The pressure drop was measured after nebulization. The end point was referred to the 45(th) dose or obstruction of the filter. Furthermore, the pressure drop after steam autoclaving was also measured. RESULTS: The maximum pressure was significantly higher with 10% acetylcysteine than with 2% sodium chloride (39.32 ± 7.22 cmH2O vs. 3.53 ± 0.90 cmH2O, p < 0.001). With acetylcysteine filters, the pressure drop over 4 cmH2O occurred earlier and had a good relationship between the degree of pressure drop and doses. The acetylcysteine group yielded a significant difference in the pressure drop compared to the newly autoclaved and the end point of inhalation (p = 0.043). CONCLUSION: This study demonstrated the aerosolized mucolytic agents could increase the pressure drop of the bacterial filters during mechanical ventilation. The pressure drop of the bacterial filters was higher with 10% acetylcysteine. It is critical to continuously monitor the expiration resistance, auto-positive end-expiratory pressure, and ventilator output waveform when aerosolized 10% acetylcysteine was used in mechanical ventilation patients.

Aetiology of hospital-acquired pneumonia and trends in antimicrobial resistance.

PURPOSE OF REVIEW: Hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) continue to present very significant diagnostic and management challenges. The development, introduction and use of a wider range of immunosuppressive therapies are leading to a broader spectrum of microorganisms causing HAP and VAP. The persistent clinical dilemma regarding their cause is that detection of a microorganism from a respiratory tract sample does not necessarily signify it is the causative agent of the pneumonia. The ever-increasing antibiotic resistance problem means that HAP and VAP are becoming progressively more difficult to treat. In this article, we review the cause, antimicrobial resistance, diagnosis and treatment of HAP and VAP and encapsulate recent developments and concepts in this rapidly moving field. RECENT FINDINGS: Although the microbial causes of HAP and VAP remain at present similar to those identified in previous studies, there are marked geographical differences. Resistance rates among Gram-negative bacteria are continually increasing, and for any species, multiresistance is the norm rather than the exception. The development and introduction of rapid point-of-care diagnostics may improve understanding of the cause of HAP and VAP and has immense potential to influence the treatment and clinical outcomes in HAP/VAP, with patients likely to receive much faster, microorganism-specific treatment with obvious downstream improvements to clinical outcome and antimicrobial stewardship. SUMMARY: We describe recent trends in aetiology of HAP and VAP and recent trends in antimicrobial resistance, including resistance mechanisms causing particular concern. The potential for novel molecular diagnostics to revolutionize the diagnosis and treatment of HAP/VAP is discussed.

Antibiotic treatment of ventilator-associated tracheobronchitis: to treat or not to treat?

PURPOSE OF REVIEW: To evaluate the data on antimicrobial therapy for ventilator-associated tracheobronchitis (VAT) to prevent ventilator-associated pneumonia (VAP), and its impact on patient outcomes. RECENT FINDINGS: Mechanically ventilated patients are at increased risk for tracheal colonization with bacterial pathogens that may progress to VAT and/or VAP. Previous studies suggest that 10-30% of patients with VAT progress to VAP, which results in increased morbidity but not mortality. Several natural history studies and small randomized controlled trials and a meta-analysis reported that appropriate, pre-emptive antibiotic treatment for VAT reduces VAP, duration of intubation and length of ICU stay. SUMMARY: This review focuses on diagnostic criteria for VAT and VAP, etiologic agents, rationale and benefits of initiating pre-emptive, appropriate antibiotic treatment for VAT to prevent VAP, improve patient outcomes and associated acute and chronic healthcare costs.

Contaminated ventilator air flow sensor linked to Bacillus cereus colonization of newborns.

We investigated Bacillus cereus-positive tracheal aspirates from infants on ventilators in a neonatal intensive care unit. Multilocus sequence typing determined a genetic match between strains isolated from samples from a case-patient and from the air flow sensor in the ventilator. Changing the sterilization method for sensors to steam autoclaving stopped transmission.

Year in review 2012: Critical Care--respiratory infections.

Over the last two decades, considerable progress has been made in the understanding of disease mechanisms and infection control strategies related to infections, particularly pneumonia, in critically ill patients. Patient-centered and preventative strategies assume paramount importance in this era of limited health-care resources, in which effective targeted therapy is required to achieve the best outcomes. Risk stratification using severity scores and inflammatory biomarkers is a promising strategy for identifying sick patients early during their hospital stay. The emergence of multidrug-resistant pathogens is becoming a major hurdle in intensive care units. Cooperation, education, and interaction between multiple disciplines in the intensive care unit are required to limit the spread of resistant pathogens and to improve care. In this review, we summarize findings from major publications over the last year in the field of respiratory infections in critically ill patients, putting an emphasis on a newer understanding of pathogenesis, use of biomarkers, and antibiotic stewardship and examining new treatment options and preventive strategies.

Effectiveness of bacterial disinfectants on surfaces of mechanical ventilator systems.

BACKGROUND: Pathogens in healthcare settings can be transmitted via skin contact and environmental media. This study investigates bacterial contamination rate on surfaces of mechanical ventilator systems and bedside equipment. An experimental study evaluates the effectiveness of 75% alcohol in killing bacteria on surfaces. METHODS: Surface swab sampling was conducted on ventilator systems and patient bedside equipment for detection of bacterial contamination. Surfaces of ventilator systems, such as faceplates, Y-pieces, and water traps, were swab sampled at 0.5, 8, and 24 hours after initial disinfection using a solution containing 0.5% sodium hypochlorite and pasteurization. The 75% alcohol aerosol was sprayed on the surfaces of faceplates, Y-pieces, and water traps on ventilator systems at 24 hours after initial disinfection, and then bacterial levels on the surfaces were evaluated. RESULTS: Detection rates of Staphylococcus aureus were measured on the handrails of mechanical ventilators (64.7%), Y-pieces of breathing circuits (86.7%), and resuscitators (60.0%). Pseudomonas aeruginosa was identified on the surfaces of Y-pieces (6.7%) and water traps (13.3%) of breathing circuits, and also on suction systems (6.7%) and resuscitators (13.3%). The positive rate for total bacterial count was clearly increased on the surfaces of faceplates, Y-pieces, and water traps at 8 hour following disinfection by 0.5% sodium hypochlorite solution and pasteurization. Concentrations of S. aureus on surfaces decreased following treatment with 75% alcohol. However, considerable P. aeruginosa growth on water trap surfaces was observed after treatment with 75% alcohol. CONCLUSIONS: The surfaces of ventilator systems, including faceplates, Y-pieces, and water traps, must be disinfected frequently (at least every 8 h) to control bacterial growth. Disinfection using 75% alcohol spray with air drying effectively decreased S. aureus on ventilator system surfaces.

[The specific compound and biological characteristics of agents of nosocomial pneumonia isolated in hospital surgery departments of Makhachkala].

The nosocomial pneumonia is the most prevailing form of hospital-acquired infection. It is the leading cause of mortality among all forms of hospital-acquired infections. In the departments of resuscitation and intensive therapy nosocomial pneumonia consists more than 25% of all hospital-acquired infections. The analysis of lavages of various components of apparatuses of artificial pulmonary ventilation in the departments of resuscitation and intensive therapy of surgery hospital departments demonstrated that gram-negative micro-flora inoculated more often (72.0%). During last years, this type of micro-flora plays leading part in development of severe forms of nosocomial pneumonia. The gram-negative bacteria consisted up to 38/8% of all isolated cultures. The similar micro-flora was isolated and from tracheobronchial lavages and it confirms the possibility of infection spreading by anesthetic breathing equipment.

Expression of ß-defensin-3 in lungs of immunocompetent rats with methicillin-resistant Staphylococcus aureus ventilator-associated pneumonia.

BACKGROUND: Despite the rising incidence and high rate of treatment failure of ventilator-associated pneumonia (VAP) due to methicillin-resistant Staphylococcus aureus (MRSA), to date there has been no rat model specifically designed for antimicrobial evaluation. ß-Defensin-3 Acronym for ß-defensin-3 is correct as (BD-3) is an antimicrobial peptide and mainly expresses in the gastrointestinal and respiratory tract. It demonstrates a broad spectrum of potent antimicrobial activity against many potentially pathogenic microbes, including multi-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium. Therefore, the authors hypothesized that the expression of BD-3 might change in lungs of rats with MRSA VAP, and this change might play an important role in the pathogenesis of VAP. MATERIALS AND METHODS: Eighty specific pathogen-free male Sprague-Dawley rats were randomly assigned to the following experimental groups: (1) N (nonventilated pneumonia) group (n=34): rats were infected intrabronchially with 0.2 mL of 10(10) cfu/mL MRSA inoculum; (2)V (ventilator-associated pneumonia) group (n=34): rats were ventilated for 4 h using the protective ventilation settings: 6 mL/kg tidal volume, 5 cm H(2)O of positive end-expiratory pressure (PEEP), 88 breaths/min, and F(i)O(2)=0.21. After ventilation, rats were inoculated intrabronchially with the same amount of MRSA as in N group; (3) P (protective mechanical ventilation) group (n=6): 0.2 mL of normal saline was instilled into lungs of rats after 4 h of ventilation as in V group; (4) C (control) group (n=6): only 0.2 mL of normal saline were instilled into lungs of rats. Rats from both P and C groups were killed 48 h after instillation of normal saline. Rats from other two groups were killed 3, 6, 12, 24, 48 h after inoculation. Pneumonia evaluation was performed by macroscopic, histopathologic, and microbiologic criteria. The expression of BD-3 in lungs was determined by immunohistochemistry staining and Western blot analysis. RESULTS: Rats inoculated after 4 h of protective mechanical ventilation rapidly developed progressive pneumonia with heterogeneous distribution of lesions and different degrees of histologic evolution predominating in lower lobes. Lung bacterial concentrations in V group at each time point were significantly higher than those of N group. It was 12.2±0.9log(10) cfu/g of tissue at h 48 in V group, and 8.7±0.4 in N group. Bacteremia occurred in nine of 10 rats at h 48 in V group, while two of 10 rats in N group. Both C and P groups showed a very low level of BD-3. Compared with C group, the expression of BD-3 at h 48 in both N and V groups significantly increased. However, the latter was significantly lower than the former. CONCLUSIONS: Rat model of MRSA VAP was obtained by intrabronchially inoculating rats with 2×10(9) cfu MRSA after 4h of protective mechanical ventilation. VAP was more severe than nonventilated pneumonia in terms of histopathologic and microbiologic criteria, especially systemic spread. This may be associated with the inhibited up-regulation of BD-3 expression by mechanical ventilation.

Socioeconomic impact on device-associated infections in limited-resource neonatal intensive care units: findings of the INICC.

PURPOSE: To evaluate the impact of country socioeconomic status and hospital type on device-associated healthcare-associated infections (DA-HAIs) in neonatal intensive care units (NICUs). METHODS: Data were collected on DA-HAIs from September 2003 to February 2010 on 13,251 patients in 30 NICUs in 15 countries. DA-HAIs were defined using criteria formulated by the Centers for Disease Control and Prevention. Country socioeconomic status was defined using World Bank criteria. RESULTS: Central-line-associated bloodstream infection (CLA-BSI) rates in NICU patients were significantly lower in private than academic hospitals (10.8 vs. 14.3 CLA-BSI per 1,000 catheter-days; p < 0.03), but not different in public and academic hospitals (14.6 vs. 14.3 CLA-BSI per 1,000 catheter-days; p = 0.86). NICU patient CLA-BSI rates were significantly higher in low-income countries than in lower-middle-income countries or upper-middle-income countries [37.0 vs. 11.9 (p < 0.02) vs. 17.6 (p < 0.05) CLA-BSIs per 1,000 catheter-days, respectively]. Ventilator-associated-pneumonia (VAP) rates in NICU patients were significantly higher in academic hospitals than in private or public hospitals [13.2 vs. 2.4 (p < 0.001) vs. 4.9 (p < 0.001) VAPs per 1,000 ventilator days, respectively]. Lower-middle-income countries had significantly higher VAP rates than low-income countries (11.8 vs. 3.8 per 1,000 ventilator-days; p < 0.001), but VAP rates were not different in low-income countries and upper-middle-income countries (3.8 vs. 6.7 per 1,000 ventilator-days; p = 0.57). When examined by hospital type, overall crude mortality for NICU patients without DA-HAIs was significantly higher in academic and public hospitals than in private hospitals (5.8 vs. 12.5%; p < 0.001). In contrast, NICU patient mortality among those with DA-HAIs was not different regardless of hospital type or country socioeconomic level. CONCLUSIONS: Hospital type and country socioeconomic level influence DA-HAI rates and overall mortality in developing countries.

Cefepime resistance and associated risk factors among Escherichia coli strains isolated from clinical specimens.

Cefepime is active against bacteria producing chromosomally and plasmid-mediated extended broad-spectrum ß-lactamase enzymes. The aim of this study was to evaluate risk factors for acquisition of cefepime resistance in Escherichia coli strains among hospitalized patients in a university hospital in Sanandaj, Iran. The study was a case-control investigation. A case patient was defined as a patient who had one isolate of a cefepime-resistant E. coli strain. A control patient was defined as a patient who had one isolate of a cefepime-sensitive E. coli strain. Cefepime resistance was determined by HiComb MIC tests (HIMEDIA, India). Out of the 255 total isolates, 73 (28.6%) were resistant to cefepime. The previous treatment of cefepime was a risk factor for acquisition of a cefepime-resistant isolate (OR = 6.32, 95% CI: 1.5-25.19, p < 0.007). The use of a ventilator was considered to be a risk for acquisition of a cefepime-resistant isolate (OR = 6.25, 95% CI: 1.86-21.02, p <0.002). The use of a catheter was also found to be a risk factor for acquisition of cefepime resistance (OR = 6.28, 95% CI: 1.86-21.02, p <0.001). There was a significant correlation between days of stay in hospital wards and cefepime resistance (p < 0.003). The main risk factors associated with cefepime resistance were previous treatment with cefepime, use of ventilator, use of catheter and days of stay in ward. More studies are needed to evaluate the role of these factors in order to control the spread of drug resistance.

Nosocomial pneumonia in the intensive care unit acquired by mechanically ventilated versus nonventilated patients.

RATIONALE: Most current information on hospital-acquired pneumonia (HAP) is extrapolated from patients with ventilator-associated pneumonia (VAP). No studies have evaluated HAP in the intensive care unit (ICU) in nonventilated patients. OBJECTIVES: To compare pneumonia acquired in the ICU by mechanically ventilated versus nonventilated patients. METHODS: We prospectively collected 315 episodes of ICU-acquired pneumonia. We compared clinical and microbiologic characteristics of patients with VAP (n = 164; 52%) and nonventilator ICU-acquired pneumonia (NV-ICUAP; n = 151; 48%). Among NV-ICUAP patients, 79 (52%) needed subsequent intubation. MEASUREMENTS AND MAIN RESULTS: Compared with NV-ICUAP, patients with VAP were more severe (APACHE-II 17 ± 6 vs. 15 ± 5; P < 0.001) and pneumonia occurred later in the ICU (8 ± 8 vs. 5 ± 6 d; P < 0.001). Etiologic diagnosis (117, 71% vs. 64, 42%; P < 0.001), nonfermenting (28% vs. 15%; P = 0.009) and enteric gram-negative bacilli (26% vs. 13%; P = 0.006), and methicillin-sensitive Staphylococcus aureus (14% vs. 6%; P = 0.031) were more frequent in VAP, likely caused by more patients with lower respiratory tract samples cultured (100% vs. 84%; P < 0.001). However, in patients with defined etiology only, the proportion of pathogens was similar between groups, except for a higher proportion of Streptococcus pneumoniae in NV-ICUAP (P = 0.045). The hospital mortality also was similar. CONCLUSIONS: Despite a lower proportion of pathogens in NV-ICUAP compared with VAP, the type of isolates and outcomes are similar regardless of whether pneumonia is acquired or not during ventilation, indicating they may depend on patients' underlying severity rather than previous intubation. With the diagnostic techniques currently recommended by guidelines, both types of patients might receive similar empiric antibiotic treatment.

[The comparison of different bronchial aspirate culturing methods in patients with ventilator-associated pneumonia (VAP)]. / Porownanie roznych sposobow pobierania materialu z drzewa oskrzelowego do badan mikrobiologicznych.

BACKGROUND: Although broncho-alveolar lavage (BAL) culture and protected specimen brush (PSB) are regarded as the most effective methods in the diagnosis of VAP, a simple endotracheal aspiration (EA) is frequently performed during routine care, because of its simplicity and low cost. We compared the effectiveness of EA with BAL and PSB in VAP patients. METHODS: Sixty-one adult VAP patients, ventilated for longer than 48 h, were cultured with all three methods. RESULTS: Positive cultures were obtained from 63.9% of patients, with Acinetobacter baumannii being the most common pathogen. There was a high positive correlation between simple aspirates and BAL (k 0.817, CI 0.664-0.840, p <0.001) and aspirates and PSB (k 0.667, CI 0.483-0.871, p <0.001). CONCLUSION: Because of the high sensitivity of bronchial aspirate culturing, compared to BAL and PSB, it can be used successfully in most cases.

The role of bacterial colonization of ventilator circuit in development of ventilator-associated pneumonia: a prospective observational cohort study.

OBJECTIVES: Ventilator-associated pneumonia (VAP) is a significant cause of prolonged hospital stay and increased mortality in mechanically ventilated children. Studies of the relationship between bacterial colonization of ventilator circuits (VCs) and VAP are lacking. This study aimed to investigate the role of bacterial colonization of VCs in the development of VAP, and to provide evidence for preventing VAP. METHODS: Mechanically ventilated patients admitted to the paediatric intensive care unit of a teaching hospital in China from October 2018 to November 2019 were enrolled. Specimens were collected from the VC and the patient's lower respiratory tract (LRT) for bacterial culture. Paired bacteria isolated from the VC and the patient's LRT, where colonization of the VC preceded that of the LRT, were evaluated for relatedness using pulsed field gel electrophoresis (PFGE). RESULTS: A total of 114 patients were included; the incidence rate of VAP was 28.1% (32/114). A total of 1368 samples were collected from VCs; 16% had positive bacterial culture. There was no significant difference in bacterial colonization of VCs between VAP and non-VAP. In 13 patients, the LRT and VC were concurrently colonized with the same bacteria, where colonization of the VC occurred before colonization of the patient's LRT. PFGE results demonstrated high correlation between bacteria from the LRT and VC in 11 patients. Among 114 mechanically ventilated children, VAP caused by bacteria from the VC occurred in six patients, accounting for 18.8% (6/32) of the overall VAP rate in this study. DISCUSSION: Bacterial colonization of the VC is a significant cause of VAP development in mechanically ventilated children. Preventive strategies for early identification and decontamination measures for contaminated VC may play a key role in preventing VAP.

Quantitative UV-C dose validation with photochromic indicators for informed N95 emergency decontamination.

With COVID-19 N95 shortages, frontline medical personnel are forced to reuse this disposable-but sophisticated-multilayer respirator. Widely used to decontaminate nonporous surfaces, UV-C light has demonstrated germicidal efficacy on porous, non-planar N95 respirators when all surfaces receive ≥1.0 J/cm2 dose. Of utmost importance across disciplines, translation of empirical evidence to implementation relies upon UV-C measurements frequently confounded by radiometer complexities. To enable rigorous on-respirator measurements, we introduce a photochromic indicator dose quantification technique for: (1) UV-C treatment design and (2) in-process UV-C dose validation. While addressing outstanding indicator limitations of qualitative readout and insufficient dynamic range, our methodology establishes that color-changing dosimetry can achieve the necessary accuracy (>90%), uncertainty (<10%), and UV-C specificity (>95%) required for UV-C dose measurements. In a measurement infeasible with radiometers, we observe a striking ~20× dose variation over N95s within one decontamination system. Furthermore, we adapt consumer electronics for accessible quantitative readout and use optical attenuators to extend indicator dynamic range >10× to quantify doses relevant for N95 decontamination. By transforming photochromic indicators into quantitative dosimeters, we illuminate critical considerations for both photochromic indicators themselves and UV-C decontamination processes.

"Don, doff, discard" to "don, doff, decontaminate"-FFR and mask integrity and inactivation of a SARS-CoV-2 surrogate and a norovirus following multiple vaporised hydrogen peroxide-, ultraviolet germicidal irradiation-, and dry heat decontaminations.

BACKGROUND: As the SARS-CoV-2 pandemic accelerates, the supply of personal protective equipment remains under strain. To combat shortages, re-use of surgical masks and filtering facepiece respirators has been recommended. Prior decontamination is paramount to the re-use of these typically single-use only items and, without compromising their integrity, must guarantee inactivation of SARS-CoV-2 and other contaminating pathogens. AIM: We provide information on the effect of time-dependent passive decontamination (infectivity loss over time during room temperature storage in a breathable bag) and evaluate inactivation of a SARS-CoV-2 surrogate and a non-enveloped model virus as well as mask and respirator integrity following active multiple-cycle vaporised hydrogen peroxide (VHP), ultraviolet germicidal irradiation (UVGI), and dry heat (DH) decontamination. METHODS: Masks and respirators, inoculated with infectious porcine respiratory coronavirus or murine norovirus, were submitted to passive decontamination or single or multiple active decontamination cycles; viruses were recovered from sample materials and viral titres were measured via TCID50 assay. In parallel, filtration efficiency tests and breathability tests were performed according to EN standard 14683 and NIOSH regulations. RESULTS AND DISCUSSION: Infectious porcine respiratory coronavirus and murine norovirus remained detectable on masks and respirators up to five and seven days of passive decontamination. Single and multiple cycles of VHP-, UVGI-, and DH were shown to not adversely affect bacterial filtration efficiency of masks. Single- and multiple UVGI did not adversely affect respirator filtration efficiency, while VHP and DH induced a decrease in filtration efficiency after one or three decontamination cycles. Multiple cycles of VHP-, UVGI-, and DH slightly decreased airflow resistance of masks but did not adversely affect respirator breathability. VHP and UVGI efficiently inactivated both viruses after five, DH after three, decontamination cycles, permitting demonstration of a loss of infectivity by more than three orders of magnitude. This multi-disciplinal approach provides important information on how often a given PPE item may be safely reused.