Bacterial Aspiration Pneumonia Research Articles

Impaired oral health: a required companion of bacterial aspiration pneumonia.

Laryngotracheal aspiration has a widely-held reputation as a primary cause of lower respiratory infections, such as pneumonia, and is a major concern of care providers of the seriously ill orelderly frail patient. Laryngeal mechanical inefficiency resulting in aspiration into the lower respiratory tract, by itself, is not the cause of pneumonia. It is but one of several factors that must be present simultaneously for pneumonia to develop. Aspiration of oral and gastric contentsoccurs often in healthy people of all ages and without significant pulmonary consequences. Inthe seriously ill or elderly frail patient, higher concentrations of pathogens in the contents of theaspirate are the primary catalyst for pulmonary infection development if in an immunocompromised lower respiratory system. The oral cavity is a complex and ever changing eco-environment striving to maintain homogeneity among the numerous microbial communities inhabiting its surfaces. Poor maintenance of these surfaces to prevent infection can result inpathogenic changes to these microbial communities and, with subsequent proliferation, can altermicrobial communities in the tracheal and bronchial passages. Higher bacterial pathogen concentrations mixing with oral secretions, or with foods, when aspirated into an immunecompromised lower respiratory complex, may result in bacterial aspiration pneumonia development, or other respiratory or systemic diseases. A large volume of clinical evidence makes it clear that oral cleaning regimens, when used in caring for ill or frail patients in hospitals and long-term care facilities, drastically reduce the incidence of respiratory infection and death. The purpose of this narrative review is to examine oral health as a required causative companionin bacterial aspiration pneumonia development, and the effectiveness of oral infection control inthe prevention of this disease.

Role of bronchoalveolar lavage in differentiation between bacterial aspiration pneumonia and gastric aspiration pneumonitis

Role of bronchoalveolar lavage in differentiation between bacterial aspiration pneumonia and gastric aspiration pneumonitis

Bacterial Aspiration Pneumonia in Generalized Convulsive Status Epilepticus: Incidence, Associated Factors and Outcome.

Suspicion of bacterial aspiration pneumonia (BAP) is frequent during generalized convulsive status epilepticus (GCSE). Early identification of BAP is required in order to avoid useless antibiotic therapy. In this retrospective monocentric study, we aimed to determine the incidence of aspiration syndrome and BAP in GCSE requiring mechanical ventilation (MV) and factors associated with the occurrence of BAP. Patients were older than 18 years and had GCSE requiring MV. To distinguish BAP from pneumonitis, tracheal aspirate and quantitative microbiological criterion were used. Out of 226 consecutive patients, 103 patients (46%) had an aspiration syndrome, including 54 (52%) with a BAP. Staphylococcus aureus represented 33% of bacterial strains. No relevant baseline characteristics differed, including serum levels of CRP, PCT, and albumin. The median duration of treatment for BAP was 7 days (5-7). Patients with BAP did not have a longer duration of MV (p = 0.18) and ICU stay (p = 0.18) than those with pneumonitis. At 3 months, 24 patients (44%) with BAP and 10 (27%) with pneumonitis had a poor functional outcome (p = 0.06). In conclusion, among patients with GCSE, half of the patients had an aspiration syndrome and one-quarter suffered from BAP. Clinical characteristics and biomarkers were not useful for differentiating BAP from pneumonitis. These results highlight the need for a method to rapidly differentiate BAP from pneumonitis, such as polymerase-chain-reaction-based techniques.

Aspiration syndromes and associated lung injury: incidence, pathophysiology and management.

Aspiration is a common condition affecting healthy or sick patients which could create an acute or chronic inflammatory reaction in the lungs. Aspiration syndromes could be categorized according to a content entering the respiratory system into bacterial aspiration pneumonia with the gastric or oropharyngeal bacteria entering, aspiration chemical pneumonitis with bacteria-freegastric acid aspiration, or aspiration of a foreign body which causes an acute pulmonary emergency. There are differences in the clinical presentation of volume-dependent aspirations (microaspiration and macroaspiration): the higher is the volume of aspiration, the greater is the injury to the patient and more serious are the health consequences (with 70 % mortality rate for hospitalized patients). Aspiration syndromes can affect both the airways and pulmonary parenchyma, leading to acute lung injury, increased hospitalization rate and worse outcomes in critically ill patients. Impaired alveolar-capillary permeability, oedema formation, neutrophilic inflammatory response and pulmonary surfactant inactivation lead to reduced lung compliance and loss of aerated lung tissue and give rise to hypoxemia and respiratory failure. This review discusses the effect of aspiration events on the pulmonary tissue. The main focus is to distinguish the differences between bacterial and chemical pneumonia, their clinical presentation and symptoms, risk factors of developing the changes, possibilities of diagnostics and management as well as prevention of aspirations. Because of a risk of serious lung damage after the aspiration, pathophysiology and processes leading to lung tissue injury are discussed in detail. Data sources represent a systematic literature search using relevant medical subject headings.

Aspiration syndromes and associated lung injury: incidence, pathophysiology and management

Aspiration is a common condition affecting healthy or sick patients which could create an acute or chronic inflammatory reaction in the lungs. Aspiration syndromes could be categorized according to a content entering the respiratory system into bacterial aspiration pneumonia with the gastric or oropharyngeal bacteria entering, aspiration chemical pneumonitis with bacteria-freegastric acid aspiration, or aspiration of a foreign body which causes an acute pulmonary emergency. There are differences in the clinical presentation of volume-dependent aspirations (microaspiration and macroaspiration): the higher is the volume of aspiration, the greater is the injury to the patient and more serious are the health consequences (with 70 % mortality rate for hospitalized patients). Aspiration syndromes can affect both the airways and pulmonary parenchyma, leading to acute lung injury, increased hospitalization rate and worse outcomes in critically ill patients. Impaired alveolar-capillary permeability, oedema formation, neutrophilic inflammatory response and pulmonary surfactant inactivation lead to reduced lung compliance and loss of aerated lung tissue and give rise to hypoxemia and respiratory failure. This review discusses the effect of aspiration events on the pulmonary tissue. The main focus is to distinguish the differences between bacterial and chemical pneumonia, their clinical presentation and symptoms, risk factors of developing the changes, possibilities of diagnostics and management as well as prevention of aspirations. Because of a risk of serious lung damage after the aspiration, pathophysiology and processes leading to lung tissue injury are discussed in detail. Data sources represent a systematic literature search using relevant medical subject headings.

The Power of a Toothbrush

The Power of a Toothbrush

誤嚥性肺炎の治療方針決定におけるプロカルシトニンの有用性(Procalcitonin utility for diagnosis and treatment of aspiration pneumonia)

要旨【目的】誤嚥性肺炎に対するプロカルシトニン（procalcitonin: PCT）の有用性を検討した。【対象】聖マリアンナ医科大学病院，東京ベイ・浦安市川医療センターの救急外来から誤嚥性肺炎で入院した成人患者で入院当日（第0病日）と第1病日のPCTがともに0.25ng/mL未満の場合は抗菌薬を投与せず，いずれかで0.25ng/mL以上の場合，抗菌薬を開始した。第4，7，10病日のPCT値の0.25ng/mL未満またはピーク値の10%未満への低下，あるいは担当医の判断で抗菌薬を終了した。【結果】患者は60人（男性26人），年齢中央値82歳［四分位範囲（interquartile range: IQR）71–89］，pneumonia severity index（PSI）は109.5（IQR 94–127）であった。第0，1病日のPCTがともに0.25ng/mL未満の14人（23.3%）は抗菌薬なしで全例治癒退院した。残り46人（76.7%）のうち1人を除く45人に抗菌薬が投与された。PCT値で抗菌薬を終了した患者が11人（24.4%），医師判断で抗菌薬を終了した患者が34人（75.6%），投与期間はそれぞれ7日（IQR 5.5–8），6.5日（IQR 5–7）で有意差は認めなかった。【結語】誤嚥性肺炎患者では入院初期のPCT陰性維持を根拠に安全に抗菌薬投与を制限できる可能性がある。

Incidence and Consequences of Near-Drowning-Related Pneumonia-A Descriptive Series from Martinique, French West Indies.

Drowning represents one major cause of accidental death. Near-drowning patients are exposed to aspiration that may result in pneumonia with life-threatening consequences. We designed this descriptive study to investigate the frequency, nature, and consequences of post-drowning pneumonia. One hundred and forty-four near-drowning patients (33 children and 111 adults) admitted during four years to the University Hospital of Martinique, French Indies, were included. Patients presented pre-hospital cardiac arrest (41%) and exhibited acute respiratory failure (54%), cardiovascular failure (27%), and lactic acidosis (75%) on admission. Empirical antibiotics, as decided by the physicians in charge, were administered in 85 patients (59%). Post-drowning early onset bacterial pneumonia was diagnosed as “possible” in 13 patients (9%) and “confirmed” in 22 patients (15%). Tracheal aspiration revealed the presence of polymorphous pharyngeal flora (59%) or one predominant bacteria species (41%) including Enterobacter aerogenes, Enterobacter cloacae, Staphylococcus aureus, Pseudomonas aeruginosa, Aeromonas hydrophilia, and Morganella morgani. Despite adequate supportive care, drowning resulted in 45 fatalities (31%). Early onset bacterial aspiration pneumonia (either possible or confirmed) did not significantly influence the risk of death. In conclusion, near-drowning–related bacterial aspiration pneumonia seems rare and does not influence the mortality rate. There is still a need for practice standardization to improve diagnosis of post-drowning pneumonia and near-drowning patient management.

Antibiotic Therapy in Comatose Mechanically Ventilated Patients Following Aspiration: Differentiating Pneumonia From Pneumonitis.

To determine the proportion of patients with documented bacterial aspiration pneumonia among comatose ICU patients with symptoms suggesting either bacterial aspiration pneumonia or non-bacterial aspiration pneumonitis. Prospective observational study. University-affiliated 30-bed ICU. Prospective cohort of 250 patients admitted to the ICU with coma (Glasgow Coma Scale score ≤ 8) and treated with invasive mechanical ventilation. None. The primary outcome was the proportion of patients with microbiologically documented bacterial aspiration pneumonia. Patients meeting predefined criteria for aspiration syndrome routinely underwent telescopic plugged catheter sampling during bronchoscopy before starting probabilistic antibiotic treatment. When cultures were negative, the antibiotic treatment was stopped. Of 250 included patients, 98 (39.2%) had aspiration syndrome, including 92 before mechanical ventilation discontinuation. Telescopic plugged catheter in these 92 patients showed bacterial aspiration pneumonia in 43 patients (46.7%). Among the remaining 49 patients, 16 continued to receive antibiotics, usually for infections other than pneumonia; of the 33 patients whose antibiotics were discontinued, only two subsequently showed signs of lung infection. In the six patients with aspiration syndrome after mechanical ventilation, and therefore without telescopic plugged catheter, antibiotic treatment was continued for 7 days. Mechanical ventilation duration, ICU length of stay, and mortality did not differ between the 43 patients with bacterial aspiration pneumonia and the 49 patients with non-bacterial aspiration pneumonitis. The 152 patients without aspiration syndrome did not receive antibiotics. Among comatose patients receiving mechanical ventilation, those without clinical, laboratory, or radiologic evidence of bacterial aspiration pneumonia did not require antibiotics. In those with suspected bacterial aspiration pneumonia, stopping empirical antibiotic therapy when routine telescopic plugged catheter sampling recovered no microorganisms was nearly always effective. This strategy may be a valid alternative to routine full-course antibiotic therapy. Only half the patients with suspected bacterial aspiration pneumonia had this diagnosis confirmed by telescopic plugged catheter sampling.

Aspirin Triggered Lipoxin A4 regulates NF-κB and induces antimicrobial peptides expression in airway epithelial cells to limit mucosal inflammation to enhance host response in pneumonia

Abstract Bacteria induced pneumonia remains a major global threat to health. Even with effective antibiotic treatment, the host response can be exuberant, resulting in tissue damage and morbidity. Resolution of inflammation is an active process governed in part by specialized pro-resolving mediators (SPMs). We hypothesized that the SPM, aspirin triggered lipoxin A4 (ATL) engaged airway mucosal epithelial cells to enhance resolution. In a murine model of bacterial aspiration pneumonia for E. coli, ATL (100 ng, iv) decreased the lung bacterial burden in an additive manner with ciprofloxacin (0.2 mg/kg, ip). Further, ATL also significantly limited neutrophils recruitment and decreased pro-inflammatory cytokine (IL-1α) and chemokine production (KC). These ATL mediated protective responses were mediated in part via regulation of NF-kB activation. In response to LPS and E. coli in vitro, ATL selectively influenced airway epithelial cells expression of NF-kB regulators A20, SIGIRR and ST2. In an in vitro bacteria killing assay by airway epithelial cells, ATL directly limited bacterial growth by increasing select antimicrobial peptides expression (LL37 and BPI). mCRAMP deficient mice (human homolog of LL37) failed to limit lung bacterial growth in E. coli pneumonia and ATL treatment was significantly less efficient in promoting host defense in these mice. In conclusion, the SPM ATL can limit pathogen mediated mucosal inflammation and enhance host defense in pneumonia via the selective regulation of NF-κB and antimicrobial peptides in airway epithelial cells. These findings with ATL provide evidence for SPM targeted treatment of the host response to pneumonia that has the potential for therapeutic benefit in combination with antibiotics.

Rapid sequence induction: its place in modern anaesthesia

In 1958, aspiration was credited as the largest cause of anaesthesia-related death by Snow and Nunn. Surprisingly, this remains the case in 2011. The Royal College of Anaesthetists National Audit Project (NAP4) calculated the incidence of fatal aspiration during general anaesthesia as one in 340 000, but acknowledging that as a probable underestimate, reported that it may be as common as one in 45 000. The risk of aspiration itself is estimated at one in 2–3000 during elective surgery and one in 6–800 during emergency surgery. Potential consequences of aspiration include chemical pneumonitis, bacterial aspiration pneumonia, acute respiratory distress syndrome, and death. While recognizing the lack of a clear definition, NAP4 recommended that, in those patients at risk of regurgitation and subsequent aspiration, a rapid sequence induction (RSI) with cricoid pressure should be the technique of choice to induce anaesthesia. However, RSI as a practice is not without risk, particularly in the critically ill population. Risks include hypoxia, failed intubation, oesophageal trauma, cardiovascular compromise, and awareness. We will describe how modern practice has deviated from the traditional, standardized RSI to an approach where management of the patient at increased risk of aspiration involves an assessment of all risks to identify suitable techniques designed to minimize those risks for that individual.

Incidence rate and causes of infection in Thai systemic sclerosis patients

Infection is a common cause of death in systemic sclerosis (SSc) but despite immunosuppressant therapy, there are few reports of opportunistic infection. To estimate the incidence of infection, to determine the etiologic organism, and to assess the risk factors for infection among Thai SSc patients. A historical cohort analysis was conducted on patients over 15years of age, diagnosed with SSc, who attended the Scleroderma Clinic at Srinagarind Hospital, Khon Kaen, Thailand, between January 1, 2005 and December 31, 2006. The medical records of 117 SSc patients were reviewed. The female-to-male ratio was 1.5:1.0. Of the total 310 person-years under observation, 63 events of infection occurred. The incidence rate of infection was 20.3 per 100 person-years (95% CI 15.6-26.0) and the incidence rate of major infection was 11.0 per 100 person-years (95% CI 8.4-16.5). The mean age and mean duration of SSc at the time of infection was 50.1±11.1years (range, 25.2-76.6) and 12.9±10.4months (range, 0.5-34.6), respectively. Urinary tract infection was the most common infection (23.8%). Opportunistic infection was found in one case (esophageal candidiasis). Esophageal dysmotility was significantly related to major infection (odds ratio [OR] 3.22). There was a clinical association between aspiration pneumonia and esophageal dysmotility (OR 1.23), as well as non-strongyloidiasis diarrhea and gastrointestinal involvement (OR 2.28). One person died due to severe bacterial aspiration pneumonia. Infection is not uncommon among SSc patients; however, opportunistic infection is rare, despite immunosuppressant therapy. Esophageal dysmotility increases the risk of major infection, particularly of aspiration pneumonia.

Anesthesia Literature Review

Anesthesia Literature Review

Diagnostic use of serum procalcitonin levels in pulmonary aspiration syndromes*

To assess the predictive accuracy of serum procalcitonin in distinguishing bacterial aspiration pneumonia from aspiration pneumonitis. Prospective observational study. Intensive care unit of a university-affiliated hospital. Sixty-five consecutive patients admitted with pulmonary aspiration and seven control subjects intubated for airway protection. None. Quantitative cultures from bronchoalveolar lavage fluid were conducted on all participants at the time of admission. Serial serum procalcitonin levels were measured on day 1 and day 3 using the procalcitonin enzyme-linked fluorescent assay. There were no differences in the median serum concentrations of procalcitonin between patients with positive bronchoalveolar lavage cultures (n = 32) and patients with negative bronchoalveolar lavage cultures (n = 33) on either day 1 or day 3 postadmission. The areas under the receiver operator characteristic curves were 0.59 (95% confidence interval, 0.47-0.72) and 0.63 (95% confidence interval, 0.5-0.75), respectively (p = .74). However, duration of mechanical ventilation and antibiotic therapy were shorter in those who had a decrease in their procalcitonin levels on day 3 from baseline compared with those who did not (6.7 ± 7.1 days and 11.1 ± 13.5 days, p = .03; and 8.2 ± 2.6 days vs. 12.8 ± 4.6 days; p < .001, respectively). Hospital mortality was associated with radiographic multilobar disease (adjusted odds ratio, 1.14; 95% confidence interval, 1.01-1.31; p = .04) and increasing procalcitonin levels (adjusted odds ratio, 5.63; 95% confidence interval, 1.56-20.29; p = .008). Serum procalcitonin levels had poor diagnostic value in separating bacterial aspiration pneumonia from aspiration pneumonitis based on quantitative bronchoalveolar lavage culture. However, serial measurements of serum procalcitonin may be helpful in predicting survival from pulmonary aspiration.

Are antibiotics indicated for the treatment of aspiration pneumonia?

Yes, for primary bacterial aspiration pneumonia and secondary bacterial infection of aspiration (chemical) pneumonitis, but not for uncomplicated chemical pneumonitis.