Healthcare-Associated Pneumonia and Hospital-Acquired Pneumonia: Bacterial Aetiology, Antibiotic Resistance and Treatment Outcomes: A Study From North India.

BACKGROUND: Data regarding the comparative profiling of HCAP and HAP from developing countries like India are scant. We set out to address the microbial aetiology, antibiotic resistance and treatment outcomes in patients with HCAP and HAP. METHODS: 318 consenting patients with HCAP (n = 165, aged 16-90 years; median 60 years; 97 males) or HAP (n = 153; aged 16-85 years; median 45 years; 92 males) presenting to a tertiary care hospital in North India from 2013 to 2015 were prospectively recruited for the study. Data on patient characteristics, microbial aetiology, APACHE II scores, treatment outcomes and mortality were studied. Clinical outcomes were compared with various possible predictors employing logistic regression analysis. RESULTS: Patients in HCAP had more comorbidity. Escherichia coli (30, 18%) and Acinetobacter baumannii (62, 41%) were the most commonly isolated bacteria in HCAP and HAP, respectively. Multidrug-resistant bacteria were isolated more frequently in HCAP, only because the incidence of extensively drug-resistant bacteria was markedly high in HAP (p = 0.00). The mean APACHE II score was lower in HCAP (17.55 ± 6.406, range 30) compared to HAP (19.74 ± 8.843, range 37; p = 0.013). The length of stay ≥ 5 days (p = 0.036) and in-hospital mortality was higher in HAP group (p = 0.002). The most reliable predictors of in-hospital mortality in HCAP and HAP were APACHE II score ≥ 17 (OR = 14, p = 0.00; HAP: OR = 10.8, p = 0.00), and septic shock (OR = 4.5, p = 0.00; HAP: OR = 6.9, p = 0.00). CONCLUSION: The patient characteristics in HCAP, treatment outcomes, bacterial aetiology, and a higher incidence of antibiotic-resistant bacteria, suggest that HCAP although not as severe as HAP, can be grouped as a separate third entity.

The dynamics of the pulmonary microbiome during mechanical ventilation in the intensive care unit and the association with occurrence of pneumonia.

RATIONALE: Ventilator-associated pneumonia (VAP) is the most common nosocomial infections in patients admitted to the ICU. The adapted island model predicts several changes in the respiratory microbiome during intubation and mechanical ventilation. OBJECTIVES: We hypothesised that mechanical ventilation and antibiotic administration decrease the diversity of the respiratory microbiome and that these changes are more profound in patients who develop VAP. METHODS: Intubated and mechanically ventilated ICU-patients were included. Tracheal aspirates were obtained three times a week. 16S rRNA gene sequencing with the Roche 454 platform was used to measure the composition of the respiratory microbiome. Associations were tested with linear mixed model analysis and principal coordinate analysis. MEASUREMENTS AND MAIN RESULTS: 111 tracheal aspirates were obtained from 35 patients; 11 had VAP, 18 did not have VAP. Six additional patients developed pneumonia within the first 48 hours after intubation. Duration of mechanical ventilation was associated with a decrease in α diversity (Shannon index; fixed-effect regression coefficient (ß): -0.03 (95% CI -0.05 to -0.005)), but the administration of antibiotic therapy was not (fixed-effect ß: 0.06; 95% CI -0.17 to 0.30). There was a significant difference in change of ß diversity between patients who developed VAP and control patients for Bray-Curtis distances (p=0.03) and for Manhattan distances (p=0.04). Burkholderia, Bacillales and, to a lesser extent, Pseudomonadales positively correlated with the change in ß diversity. CONCLUSION: Mechanical ventilation, but not antibiotic administration, was associated with changes in the respiratory microbiome. Dysbiosis of microbial communities in the respiratory tract was most profound in patients who developed VAP.

Tracheal tube biofilm removal through a novel closed-suctioning system: an experimental study.

BACKGROUND: Tracheal tube biofilm develops during mechanical ventilation. We compared a novel closed-suctioning system vs standard closed-suctioning system in the prevention of tracheal tube biofilm. METHODS: Eighteen pigs, on mechanical ventilation for 76 h, with P. aeruginosa pneumonia were randomized to be tracheally suctioned via the KIMVENT* closed-suctioning system (control group) or a novel closed-suctioning system (treatment group), designed to remove tracheal tube biofilm through saline jets and an inflatable balloon. Upon autopsy, two tracheal tube hemi-sections were dissected for confocal and scanning electron microscopy. Biofilm area, maximal and minimal thickness were computed. Biofilm stage was assessed. RESULTS: Sixteen animals were included in the final analysis. In the treatment and control group, the mean (sd) pulmonary burden was 3.34 (1.28) and 4.17 (1.09) log cfu gr(-1), respectively (P=0.18). Tracheal tube P. aeruginosa colonization was 5.6 (4.9-6.3) and 6.2 (5.6-6.9) cfu ml(-1) (median and interquartile range) in the treatment and control group, respectively (P=0.23). In the treatment group, median biofilm area was 3.65 (3.22-4.21) log10 µm2 compared with 4.49 (4.27-4.52) log10 µm2 in the control group (P=0.031). In the treatment and control groups, the maximal biofilm thickness was 48.3 (26.7-71.2) µm (median and interquartile range) and 88.8 (43.8-125.7) µm, respectively. The minimal thickness in the treatment and control group was 0.6 (0-4.0) µm and 23.7 (5.3-27.8) µm (P=0.040) (P=0.017). Earlier stages of biofilm development were found in the treatment group (P<0.001). CONCLUSIONS: The novel CSS reduces biofilm accumulation within the tracheal tube. A clinical trial is required to confirm these findings and the impact on major outcomes.

Atypical pneumonia.

PURPOSE OF REVIEW: We present the key advances in the infections that clinicians conventionally associate with atypical pneumonia: legionellosis, Mycoplasma pneumonia, Chlamydophila species pneumonia and Q fever. RECENT FINDINGS: There have been significant developments in molecular diagnosis to include Mycoplasma pneumoniae and Chlamydophila pneumoniae in multiplex PCR of respiratory specimens. There are diagnostic challenges in distinguishing carriage from infection, which is recognized in C. pneumoniae and now also evident in M. pneumoniae. Macrolide-resistant M. pneumoniae has emerged in Asia. There are new antimicrobials on the horizon in the ketolide class with activity against typical and atypical pathogens and useful empirical agents. SUMMARY: There are few advances in our knowledge of the epidemiology of atypical pathogens or the effectiveness of antimicrobial therapy--empirical or pathogen specific. However, if molecular testing becomes widely implemented, there will be an increased understanding of the epidemiology and presentation of atypical pneumonia and a shift to more targeted antimicrobial therapy.

Effects of isolation rooms on the prevalence of hospital acquired pneumonia in a respiratory ICU.

BACKGROUND: The incidence of hospital acquired pneumonia (HAP) varies according to the type of intensive care units (ICUs). AIM: The aims of this study were to determine the frequency of hospital acquired pneumonia (HAP) and the effect of isolation rooms on the frequency of pneumonia in the ICU. MATERIALS AND METHODS: The present investigation was carried out between January 2004 and July 2008. The ICU, which was 4-bed ward-type between January 2004 and February 2006 (1st period), was reconfigured as isolated rooms with only 2 beds each after March 2006 (2nd period). 153 and 379 patients were followed up in the ICU in the 1st and 2nd periods, respectively. Blood, sputum, and deep tracheal aspiration cultures were used for the isolation of the causative agents. RESULTS: No significant difference was detected between the general characteristics of patients. HAP developed in 101 patients (19%). The prevalence of HAP was 22.9% in the 1st period and 17.4% in the 2nd period. During the 1st and 2nd periods, the HAP infection densities were 22.2 and 16.1/1000 patient-days and the ventilator-associated pneumonia densities were 48.1 and 37.6/1000 ventilator-days, respectively. Eighty-six percent of HAP was ventilator-associated pneumonia (VAP). CONCLUSIONS: Isolation rooms in the ICU may be an effective strategy to control and decrease the rate of pneumonia in the ICU in addition to other preventive strategies.

Nursing-home-acquired pneumonia in Germany: an 8-year prospective multicentre study.

OBJECTIVE: To determine differences in aetiologies, initial antimicrobial treatment choices and outcomes in patients with nursing-home-acquired pneumonia (NHAP) compared with patients with community-acquired pneumonia (CAP), which is a controversial issue. METHODS: Data from the prospective multicentre Competence Network for Community-acquired pneumonia (CAPNETZ) database were analysed for hospitalised patients aged ≥65 years with CAP or NHAP. Potential differences in baseline characteristics, comorbidities, physical examination findings, severity at presentation, initial laboratory investigations, blood gases, microbial investigations, aetiologies, antimicrobial treatment and outcomes were determined between the two groups. RESULTS: Patients with NHAP presented with more severe pneumonia as assessed by CRB-65 (confusion, respiratory rate, blood pressure, 65 years and older) score than patients with CAP but received the same frequency of mechanical ventilation and less antimicrobial combination treatment. There were no clinically relevant differences in aetiology, with Streptococcus pneumoniae the most important pathogen in both groups, and potential multidrug-resistant pathogens were very rare (<5%). Only Staphylococcus aureus was more frequent in the NHAP group (n=12, 2.3% of the total population, 3.1% of those with microbial sampling compared with 0.7% and 0.8% in the CAP group, respectively). Short-term and long-term mortality in the NHAP group was higher than in the CAP group for patients aged ≥65 years (26.6% vs 7.2% and 43.8% vs 14.6%, respectively). However, there was no association between excess mortality and potential multidrug-resistant pathogens. CONCLUSIONS: Excess mortality in patients with NHAP cannot be attributed to a different microbial pattern but appears to result from increased comorbidities, and consequently, pneumonia is frequently considered and managed as a terminal event.

The emergence of a highly transmissible lineage of cbl+ Pseudomonas (Burkholderia) cepacia causing CF centre epidemics in North America and Britain.

The rapid increase in Pseudomonas (Burkholderia) cepacia infection in cystic fibrosis (CF) patients suggests epidemic transmission, but the degree of transmissibility remains controversial as conflicting conclusions have been drawn from studies at different CF centres. This report provides the first DNA sequence-based documentation of a divergent evolutionary lineage of P. cepacia associated with CF centre epidemics in North America (Toronto) and Europe (Edinburgh). The involved epidemic clone encoded and expressed novel cable (Cbl) pili that bind to CF mucin. The sequence of the cblA pilin subunit gene carried by the epidemic isolates proved to be invariant. Although it remains to be determined how many distinct, highly transmissible lineages exist, our results provide both a DNA sequence and chromosomal fingerprint that can be used to screen for one such particularly infectious, transatlantic clone.

Profile of bacterial pneumonia during Hajj.

BACKGROUND & OBJECTIVES: The congregation of a large number of people during Hajj seasons from different parts of the world in overcrowded conditions within a confined area for a long period of time presents many public health challenges and health risks. One of the main health problems of the crowding is ease transmission of pneumonia by air droplets. This study was aimed to determine the most common causes of bacterial pneumonia during the 2005 Hajj season and to relate the findings with clinical conditions. METHODS: A total of 141 patients with suspected pneumonia from the three main tertiary care hospitals in Makkah, Saudi Arabia, were investigated during Hajj season, 2005. Sputum and serum samples were collected and investigated for the possible presence of typical or atypical causative agents. RESULTS: Of the 141 clinically suspected pneumonia cases, 76 (53.9%) were confirmed positive by microbiological tests. More than 94 per cent of the confirmed cases were in the age group >50 yr, and 56.6 per cent of the cases were men. The most frequent isolates were Candida albicans (28.7%) and Pseudomonas aeruginosa (21.8%), followed by Legionella pneumophila (14.9%) and Klabsiella pneumoniae (9.2%). More than one causative pathogens were isolated in 15 patients (16.3%), and 55 per cent of patients were diabetic. INTERPRETATION & CONCLUSIONS: Clinicians should be aware that typical pneumonia treatment regimens may not work well during the Hajj season due to the wide variety of isolated organisms. This necessitates taking a sputum sample before starting treatment for identification and sensitivity testing. Special precautions need to be taken for >50 yr old patients.

Stepwise pathogenic evolution of Mycobacterium abscessus.

Although almost all mycobacterial species are saprophytic environmental organisms, a few, such as Mycobacterium tuberculosis, have evolved to cause transmissible human infection. By analyzing the recent emergence and spread of the environmental organism M. abscessus through the global cystic fibrosis population, we have defined key, generalizable steps involved in the pathogenic evolution of mycobacteria. We show that epigenetic modifiers, acquired through horizontal gene transfer, cause saltational increases in the pathogenic potential of specific environmental clones. Allopatric parallel evolution during chronic lung infection then promotes rapid increases in virulence through mutations in a discrete gene network; these mutations enhance growth within macrophages but impair fomite survival. As a consequence, we observe constrained pathogenic evolution while person-to-person transmission remains indirect, but postulate accelerated pathogenic adaptation once direct transmission is possible, as observed for M. tuberculosis Our findings indicate how key interventions, such as early treatment and cross-infection control, might restrict the spread of existing mycobacterial pathogens and prevent new, emergent ones.

Nursing home-acquired pneumonia: a 10 year single-centre experience.

BACKGROUND: Pneumonia among nursing home (NH) residents has increased considerably in recent years, but it remains unclear whether it should be considered as community-acquired pneumonia (CAP) or a new category of infection. METHODS: 150 consecutive cases of NH-acquired pneumonia (NHAP) (from 1 February 1997 to 1 July 2007) were analysed. RESULTS: Patients (median age, 82 years; range, 77-87 years) showed numerous co-morbidities, (neurological, 55%; pulmonary, 38%; cardiac, 35%) and severe disability for daily activities (partial, 32%; total, 31%). Cases of NHAP were mainly classified as mild to moderate according to the CRB-65 score (CRB-65 classes 0-1 and 2, 41% each). In-hospital and 30-day mortality were 8.7% and 20%, respectively. Aetiology was defined in 57 cases (38%). The most common isolates were Streptococcus pneumoniae (58%), Enterobacteriaceae (Gram-negative bacteria (GNB)) (9%), atypical bacteria (7%), respiratory viruses (5%), methicillin-resistant Staphylococcus aureus (MRSA) (5%) and Legionella pneumophila (5%). The most frequent causes of treatment inadequacy were use of beta-lactams alone (25%) and lack of aspiration assessment (15%). Prognostic factors of 1-month mortality were neurological comorbidities (OR 4.5; 95% CI 1.3 to 15.7; p=0.020), septic shock (OR 6.6; 95% CI 1.3 to 34.0; p=0.025), pleural effusion (OR 3.6; 95% CI 1.1 to 11.7; p=0.036) and isolation of GNB or MRSA (OR 16.4; 95% CI 2.1 to 128.9; p=0.008). CONCLUSIONS: The patients show clinical characteristics (eg, age and co-morbidities) comparable with those with hospital-acquired pneumonia. However, microbiological and mortality data of patients with NHAP are more similar to the data of those with CAP. Isolation of GNB or MRSA was associated with increased mortality risk. CAP empirical antibiotic coverage is still indicated in NHAP, although specific risk factors for multidrug-resistant infections should be assessed on an individual basis.

Pig trotters lung--novel domestic transmission of Pasteurella multocida.

Pasteurella multocida is a non-motile, faculatively-anaerobic, gram-negative bacillus associated with a spectrum of human disease. Direct and indirect zoonotic transmission is recognised with animal bites being most frequently encountered as a result of salivary colonisation in farm and domestic animals. Despite the prevalence of P. multocida in swine herds, the relationship between porcine colonisation and human disease is poorly established. This lesson reports a previously unrecognised mode of zoonotic transmission in respiratory pasteurellosis; domestic cooking of pig trotters.

[A case of hospital-acquired pneumonia caused by intermediately susceptible carbapenem Acinetobacter baumannii].

The incidence of Acinetobacter baumannii pneumonia in hospital-acquired pneumonia in Japan is rare. We report a case of ventilator-associated A. baumanii pneumonia. A 69-year-old man admitted for fever was diagnosed with Streptococcus pneumoniae pneumonia based on chest radiography, urine antigen, and sputum examination. Despite appropriate antibiotics, the pneumonia progressed, necessitating intensive respiratory management. Ten days there after, he suffered sudden septic shock and superimposed pneumonia despite both carbapenem and fluoroquinolone administration. A. baumanii was detected from blood and sputum. Piperacilline/tazobactam, amikacin, and intensive care saved his life.

Occupational transmission of Acinetobacter baumannii from a United States serviceman wounded in Iraq to a health care worker.

BACKGROUND: Acinetobacter baumannii is increasingly recognized as being a significant pathogen associated with nosocomial outbreaks in both civilian and military treatment facilities. Current analyses of these outbreaks frequently describe patient-to-patient transmission. To date, occupational transmission of A. baumannii from a patient to a health care worker (HCW) has not been reported. We initiated an investigation of an HCW with a complicated case of A. baumannii pneumonia to determine whether a link existed between her illness and A. baumannii-infected patients in a military treatment facility who had been entrusted to her care. METHODS: Pulsed-field gel electrophoresis and polymerase chain reaction/electrospray ionization mass spectrometry, a form of multilocus sequencing typing, were done to determine clonality. To further characterize the isolates, we performed a genetic analysis of resistance determinants. RESULTS AND CONCLUSIONS: A "look-back" analysis revealed that the multidrug resistant A. baumannii recovered from the HCW and from a patient in her care were indistinguishable by pulsed-field gel electrophoresis. In addition, polymerase chain reaction/electrospray ionization mass spectrometry indicated that the isolates were similar to strains of A. baumannii derived from European clone type II (Walter Reed Army Medical Center strain type 11). The exposure of the HCW to the index patient lasted for only 30 min and involved endotracheal suctioning without use of an HCW mask. An examination of 90 A. baumannii isolates collected during this investigation showed that 2 major and multiple minor clone types were present and that the isolates from the HCW and from the index patient were the most prevalent clone type. Occupational transmission likely occurred in the hospital; HCWs caring for patients infected with A. baumannii should be aware of this potential mode of infection spread.

Panton-Valentine Leukocidin associated with community acquired methicillin resistant Staphylococcus aureus: a case report and review of interim guidelines.

We report a case of community acquired methicillin resistant Staphylococcus aureus pneumonia. The causative organism was positive for the toxin Panton-Valentine Leukocidin. This resulted in a severe pneumonia requiring a prolonged stay on our intensive care unit. This infection is becoming more common in the United Kingdom. It can cause a far more aggressive illness than the hospital acquired infection with a high mortality if it becomes an invasive infection. The Department of Health has recently produced interim guidelines for its treatment which we have also reviewed.

Bordetella bronchiseptica pneumonia: beware of the dog!

We report the case of a 35-year-old quadriplegic male with confirmed Bordetella bronchiseptica pneumonia, manifesting with acute hypoxic respiratory failure on a background of chronic hypercarbia requiring mechanical ventilation in intensive care.B. bronchiseptica are known to colonise the upper respiratory tracts of many mammals but are very rarely responsible for acute respiratory tract infections in humans.A review of the literature suggests preponderance for immunocompromised or immunoincompetent patients who have experienced environmental exposure to colonised animals. The disease pattern of B. bronchiseptica infection is non-uniform and while it is rarely described as a commensal or colonising organism, very few case reports describe severe respiratory infections.

Transmission of Panton-Valentine leukocidin-positive Staphylococcus aureus between patients with cystic fibrosis.

Panton-Valentine leukocidin-producing Staphylococcus aureus is an emerging pathogen world-wide, causing necrotizing lung infections in otherwise healthy individuals. We describe 2 episodes of patient-to-patient transmission of Panton-Valentine leukocidin-producing S. aureus, resulting in acute, life-threatening pulmonary complications in patients with cystic fibrosis. Appropriate infection control measures may be warranted to prevent similar episodes.

Recent advances in community-acquired pneumonia: inpatient and outpatient.

Community-acquired pneumonia (CAP) is a common illness, with the majority of patients treated out of the hospital, yet the greatest burden of the cost of care comes from inpatient management. In the past several years, the management of these patients has advanced, with new information about the natural history and prognosis of illness, the utility of serum markers to guide management, the use of appropriate clinical tools to guide the site-of-care decision, and the finding that guidelines can be developed in a way that improves patient outcome. The challenges to patient management include the emergence of new pathogens and the progression of antibiotic resistance in some of the common pathogens such as Streptococcus pneumoniae. Few new antimicrobial treatment options are available, and the utility of some new therapies has been limited by drug-related toxicity. Ancillary care for severe pneumonia with activated protein C and corticosteroids is being studied, but recently, inpatient care has been most affected by the development of evidence-based "core measures" for management that have been promoted by the Centers for Medicare and Medicaid Services, which form the basis for the public reporting of hospital performance in CAP care.

Nursing home outbreak of invasive group a streptococcal infections caused by 2 distinct strains.

OBJECTIVE: To identify factors contributing to a cluster of deaths from invasive group A streptococcus (GAS) infection in a nursing home facility and to prevent additional cases. DESIGN: Outbreak investigation. SETTING: A 146-bed nursing home facility in northern Nevada. METHODS: We defined a case as the isolation of GAS from a normally sterile site in a resident of nursing home A. To identify case patients, we reviewed resident records from nursing home A, the local hospital, and the hospital laboratory. We obtained oropharyngeal and skin lesion swabs from staff and residents to assess GAS colonization and performed emm typing on available isolates. To identify potential risk factors for transmission, we performed a cohort study and investigated concurrent illness among residents and surveyed staff regarding infection control practices. RESULTS: Six residents met the case patient definition; 3 (50%) of them died. Among invasive GAS isolates available for analysis, 2 distinct strains were identified: emm11 (3 isolates) and emm89 (2 isolates). The rate of GAS carriage was 6% among residents and 4% among staff; carriage isolates were emm89 (8 isolates), emm11 (2 isolates), and emm1 (1 isolate). Concurrently, 35 (24%) of the residents developed a respiratory illness of unknown etiology; 41% of these persons died. Twenty-one (30%) of the surveyed employees did not always wash their hands before patient contacts, and 27 (38%) did not always wash their hands between patient contacts. CONCLUSIONS: Concurrent respiratory illness likely contributed to an outbreak of invasive GAS infection from 2 strains in a highly susceptible population. This outbreak highlights the importance of appropriate infection control measures, including respiratory hygiene practices, in nursing home facilities.