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BACKGROUND Clostridium ramosum is an anaerobic, spore-producing, gram-positive rod, enteric pathogen that is difficult to identify and is rarely pathogenic. We present a case of Clostridium ramosum bacteremia secondary to aspiration pneumonia in a 65-year-old immunocompromised man on chemotherapy for follicular lymphoma. CASE REPORT We report the case of a 65-year-old man, on active chemotherapy for follicular lymphoma, presenting with a fever of 38.3°C, nonproductive cough, fatigue, and confusion. Physical examination was unremarkable except for +2 lower-extremity pitting edema. CT abdomen pelvis showed left lower-lung consolidation and CT chest angiogram showed that the consolidation was concerning for infarct verses abscess and segmental/subsegmental pulmonary emboli despite anticoagulation use. Blood cultures later grew Clostridium ramosum, which was successfully treated with IV piperacillin-tazobactam. Subsequent outpatient imaging demonstrated resolution of the lung consolidation. CONCLUSIONS Our case highlights the rare diagnosis of Clostridium ramosum bacteremia secondary to aspiration pneumonia in an immunocompromised patient and our approach to management. We highlight the difficulties in identification of Clostridium ramosum, rare pathogenicity, risk factors, and potential sources.

"Pigmentibacter ruber" was first reported in 2021, a novel bacterium of the family Silvanigrellaceae, isolated from human blood of the patient with aspiration pneumonia after the drowning accident in Republic of China. However, until now, there is only one report describing "P. ruber" infection, and no case of isolation from natural environment has been reported so far. Thus, the infectivity and pathogenicity of "Pigmentibacter" spp. has not been clearly understood. In this report, we described the fatal case of "Pigmentibacter" bacteremia subsequently occurred after aspiration pneumonia probably due to accidental ingestion of irrigation water in the elderly patient. Despite administration of broad-spectrum antibiotic, the patient dramatically deteriorated and eventually deceased. Whole-genome sequencing showed the strain isolated from the patient was identified as "Pigmentibacter" sp. (designated as strain Takaoka) and antimicrobial sensitivity testing showed it displayed high minimum inhibitory concentrations against various antibiotics including β-lactam. Further studies are needed to clarify the clinical characteristics of "Pigmentibacter" and its relative's infections and their antimicrobial sensitivity; however, the present case supported the clinical characteristics of "Pigmentibacter" infection, which can lead to bacteremia following aspiration pneumonia caused by mis-swallowing contaminated water, and poor outcome potentially due to multidrug resistances., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to declare., (Copyright © 2024 Japanese Society of Chemotherapy, Japanese Association for Infectious Diseases, and Japanese Society for Infection Prevention and Control. Published by Elsevier Ltd. All rights reserved.)

The number of older people with impaired swallowing function increases with aging population. Aspiration pneumonia is one of the most cases of pneumonia developing among older people. As aspiration pneumonia may develop as a result of age-related deterioration, it is crucial to consider it as an unavoidable event with aging. While pneumonia is diagnosed based on respiratory symptoms and radiological features, the lung involvement of aspiration pneumonia may be undetectable via a frontal chest radiograph in some cases. Bacterial profiles show the predominance of drug-resistant bacteria, such as Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA), but isolated bacteria from respiratory samples do not necessarily indicate causative pathogens. Furthermore, there is no evidence regarding treatment superiority using broad-spectrum antibiotics compared with narrow-spectrum antibiotics. Even if isolated pathogens are a causative factor for pneumonia among older patients, the use of broad-spectrum antibiotics covering the bacteria may not improve their outcomes. Therefore, we propose a treatment strategy independent of the risk of drug resistance focusing on the discrimination of patients who are unlikely to respond to broad-spectrum antibiotics. An aspiration risk is associated with increased in-hospital mortality in patients with pneumonia, which could also lead to a greater risk of poor long-term outcomes with increased 1-year mortality. Advance care planning is now recognized as a process for communication and medical decision-making across the life course. This approach would be widely recommended for older people with aspiration risk., Competing Interests: Declaration of competing interest Kosaku Komiya received lecture fees from Kyorin pharmaceuticals, MSD pharmaceuticals, and Shionogi pharmaceuticals. Izumi Yamatani and Jun-ichi Kadota have no conflict of interest., (Copyright © 2024 The Japanese Respiratory Society. Published by Elsevier B.V. All rights reserved.)

Objectives: Lower respiratory tract infections (LRTIs) are often caused by the patient's own oral commensal bacteria. Causative bacteria must be identified to select the appropriate antimicrobial agents; however, the pathogens are identified via routine culture methods in only approximately half of LRTI cases., Methods: To investigate LRTI-associated bacteria, we conducted culture testing under aerobic and anaerobic conditions using culture-independent partial 16S rRNA gene amplicon sequencing analysis using a high-throughput sequencer in cases of aspiration pneumonia and lung abscesses., Results: Culture testing of 17 aspiration pneumonia cases revealed Streptococcus spp. (n = 13), Prevotella spp. (n = 9), and Veillonella spp. (n = 8); 16S rRNA analysis of these cases yielded Streptococcus spp. (n = 16), Veillonella spp. (n = 12), Haemophilus spp. (n = 12), Prevotella spp. (n = 11), and Rothia spp. (n = 11). Culture testing of 8 lung abscess cases revealed Streptococcus spp. (n = 7) and Fusobacterium spp. (n = 4); 16S rRNA analysis of these cases yielded Fusobacterium spp. (n = 8), Prevotella spp. (n = 7), Streptococcus spp. (n = 6), and Porphyromonas spp. (n = 5). All taxa with abundance ratios of ≥50% on the 16S rRNA analysis were also detected in the cultures. However, several taxa were either undetected in the cultures despite relatively high abundance ratios on the 16S rRNA analysis or negative on the 16S rRNA analysis and isolated only by culturing., Conclusion: Our data provide a comprehensive list of bacterial taxa that may be associated with aspiration pneumonia and lung abscesses. In empirically treating LRTIs, this information will help determine the best treatment against the targeted anaerobes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Objective: To compare hospital outcomes associated with commonly used antibiotic therapies for aspiration pneumonia in children with neurologic impairment (NI)., Design/methods: A retrospective study of children with NI hospitalized with aspiration pneumonia at 39 children's hospitals in the Pediatric Health Information System database. Exposure was empiric antibiotic therapy classified by antimicrobial activity. Outcomes included acute respiratory failure, intensive care unit (ICU) transfer, and hospital length of stay (LOS). Multivariable regression evaluated associations between exposure and outcomes and adjusted for confounders, including medical complexity and acute illness severity., Results: In the adjusted analysis, children receiving Gram-negative coverage alone had two-fold greater odds of respiratory failure (odds ratio [OR] 2.15; 95% CI: 1.41-3.27), greater odds of ICU transfer (OR 1.80; 95% CI: 1.03-3.14), and longer LOS [adjusted rate ratio (RR) 1.28; 95% CI: 1.16-1.41] than those receiving anaerobic coverage alone. Children receiving anaerobic and Gram-negative coverage had higher odds of respiratory failure (OR 1.65; 95% CI: 1.19-2.28) than those receiving anaerobic coverage alone, but ICU transfer (OR 1.15; 95% CI: 0.73-1.80) and length of stay (RR 1.07; 95% CI: 0.98-1.16) did not statistically differ. For children receiving anaerobic, Gram-negative, and P. aeruginosa coverage, LOS was shorter (RR 0.83; 95% CI: 0.76-0.90) than those receiving anaerobic coverage alone; odds of respiratory failure and ICU transfer rates did not significantly differ., Conclusions: Anaerobic therapy appears to be important in the treatment of aspiration pneumonia in children with NI. While Gram-negative coverage alone was associated with worse outcomes, its addition to anaerobic therapy may not yield improved outcomes.

Competing Interests: Disclosure The authors have nothing to disclose.

Acinetobacter baumannii is a major cause of illness in hospitalized patients and the most important and common pathogen in nosocomial outbreaks worldwide. In animals, A. baumannii has been associated with respiratory infections in a group of minks, leading to pneumonia and acute mortality. This report documents a case of aspiration bronchopneumonia in a wild European hare caused by A. baumannii . A free-ranging, adult male European hare was submitted to necropsy after acute trauma due to being hit by a car. Its lungs showed consolidation with abscess in the middle and cranial lobes. Histopathologic evaluation revealed liquefactive necrosis associated with neutrophilic infiltration, cellular debris, plant material, and bacterial myriads surrounded by moderate neutrophils, macrophages, multinucleated giant cells, lymphocytes, and plasma cell inflammation. Acinetobacter baumannii was isolated from lung tissue.

Background: The emergence of multi-drug resistant pathogens is an urgent health-related problem, and the appropriate use of antibiotics is imperative. It is often difficult to identify the causative bacteria in patients with aspiration pneumonia because tracheal aspirate contains contaminants of oral bacteria. We investigated the dynamics of microbiota in mechanically ventilated patients with aspiration pneumonia to develop a treatment strategy., Methods: Twenty-two intubated patients with aspiration pneumonia were recruited. Saliva and tracheal aspirate of the subjects were collected at three time points: (A) within 2 h after intubation, (B) just before administration of antibiotics, and (C) 48-72 h after administration of antibiotics. The microbiota in each specimen was analyzed by using the 16S rRNA gene clone library sequencing method. Bacterial floras of the samples were analyzed by principal component analysis., Results: Principal component analysis based on the composition of genus revealed that although the changes of microbiota in the saliva from (A) to (B) were not clear, the composition of anaerobes in the tracheal aspirate (B) was lower than (A). In fact, the reduction of anaerobes, not in the saliva but in the tracheal aspirate from (A) to (B), was confirmed by incident rate ratios estimated by a multilevel Poisson regression model (p < 0.001). The extent of decrease in anaerobes was fully dependent on the time difference between the sampling of tracheal aspirate (A) and (B)-in particular, over 3 h of mechanical ventilation. This indicates that the alterations of microbiota (involving the reduction of anaerobes in the lower respiratory tract) occurred during mechanical ventilation prior to the administration of antibiotics. After the administration of antibiotics, Enterobacter spp., Corynebacterium spp., Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus, and Granulicatera adiacens were predominantly detected in the tracheal aspirate (C)., Conclusion: The microbiota of the lower respiratory tract changes dynamically during mechanical ventilation and during the administration of antibiotics in intubated patients with aspiration pneumonia. Antibiotics should be selected on the premise that dynamic changes in microbiota (involved in the reduction of anaerobes) may occur during the mechanical ventilation in these patients.

Introduction : Aspiration pneumonia is a subclass of community-acquired pneumonia that is expected to have an increasing contribution in mortality and morbidity, particularly in the elderly population over the next coming decades. While studies have revealed significant progress in identifying risk factors for aspiration pneumonia, the clinical presentation and diagnosis remain challenging to healthcare providers. Areas covered : We conducted a broad literature review using the MeSH heading in PubMed/MEDLINE of 'aspiration pneumonia' from January 1970 to July 2019. The understanding of the microbiology of aspiration pneumonia has evolved from a possible shift in the causative organisms away from anaerobes to traditional community-acquired pneumonia organisms. The importance of this shift is not yet known, but it has questioned the pathogenic role of anaerobes, appropriate anaerobic testing and the role of these pathogens in the pulmonary microbiome in patients with pneumonia. The identification of risk factors led to strategies to prevent or minimize the risk of aspiration pneumonia with moderate success. Expert opinion : Our expert opinion is that further research is needed to determine the role of the microbiome with aspiration pneumonia and patient risk factors. There is also a great need to develop clinical tools to help providers diagnose, treat, and prevent aspiration pneumonia.

Background: Aspiration pneumonia is a serious problem among elderly patients; it is caused by many risk factors including dysphagia, poor oral hygiene, malnutrition, and sedative medications. The aim of this study was to define a convenient procedure to objectively evaluate the risk of aspiration pneumonia in the clinical setting., Methods: This prospective study included an aspiration pneumonia (AP) group, a community-acquired pneumonia (CAP) group, and a control (Con) group (patients hospitalized for lung cancer chemotherapy). We used the Oral Health Assessment Tool (OHAT), which assesses oral hygiene, and evaluated performance status, body mass index, serum albumin levels, substance P values in plasma, and oral bacterial counts., Results: The oral health as assessed by the OHAT of the aspiration pneumonia group was significantly impaired compared with that of the CAP group and the control (5.13 ± 0.18, 4.40 ± 0.26, 3.90 ± 0.22, respectively; p < 0.05). The oral bacterial count in the aspiration pneumonia group (7.20 ± 0.11) was significantly higher than that in the CAP group (6.89 ± 0.12), consistent with the OHAT scores. Oral bacterial count was significantly reduced by oral care., Conclusions: OHAT and oral bacterial counts can be a tool to assess the requirement of taking oral care and other preventive procedures in patients at high risk of aspiration pneumonia.

Aspiration pneumonia is an infectious disease of the lungs caused by inhalation of saliva or foods, associated with swallowing dysfunction. Therefore, the major causative organisms are oral or gastric bacteria. In this study, we evaluated the antimicrobial susceptibility patterns of the anaerobic bacteria which can cause aspiration pneumonia, Fusobacterium spp., Finegoldia magna, Bacteroides fragilis, Peptostreptococcus spp., Prevotella spp., and Streptococcus milleri group to ceftriaxone, cefmetazole, flomoxef, ampicillin/sulbactam, and ampicillin. We also tested the β-lactamase activities of each of the bacterial strains. Fusobacterium spp. and Finegoldia magna were susceptible to all of the tested antimicrobial drugs, except ampicillin, and showed no β-lactamase activity. The Streptococcus milleri group, Bacteroides fragilis, and Peptostreptococcus spp. showed decreased susceptibility to cefmetazole or flomoxef as compared to the susceptibility levels documented in a previous report. There was one strain of Peptostreptococcus anaerobius which was not susceptible to ampicillin/sulbactam, but also showed no β-lactamase activity, suggesting that this strain harbored a mechanism of resistance other than the production of β-lactamase. The susceptibility of Prevotella spp. to ceftriaxone was also decreased as compared to the susceptibility level documented in a previous report. Furthermore, β-lactamase-positive strains were found even among ceftriaxone-susceptible strains. Elderly persons with swallowing dysfunction carry a risk of recurrent episodes of aspiration pneumonia and repeated use of antibiotics increases the risk of development of antibiotic resistance. In the present study, the antibiotic susceptibilities of some of organisms which can cause aspiration pneumonia were found to be decreased as compared to the susceptibility levels documented in a previous report. Therefore, surveillance of the antimicrobial susceptibility patterns of these bacteria is recommended to prevent the development of resistance., (Copyright © 2019. Published by Elsevier Ltd.)

Background: Children with oropharyngeal dysphagia have impaired airway protection mechanisms and are at higher risk for pneumonia and other pulmonary complications. Aspiration of gastric contents is often implicated as a cause for these pulmonary complications, despite being supported by little evidence. The goal of this study is to determine the relative contribution of oropharyngeal and gastric microbial communities to perturbations in the lung microbiome of children with and without oropharyngeal dysphagia and aspiration., Methods: We conducted a prospective cohort study of 220 patients consecutively recruited from a tertiary aerodigestive center undergoing simultaneous esophagogastroduodenoscopy and flexible bronchoscopy. Bronchoalveolar lavage, gastric and oropharyngeal samples were collected from all recruited patients and 16S sequencing was performed. A subset of 104 patients also underwent video fluoroscopic swallow studies to assess swallow function and were categorized as aspiration/no aspiration. To ensure the validity of the results, we compared the microbiome of these aerodigestive patients to the microbiome of pediatric patients recruited to a longitudinal cohort study of children with suspected GERD; patients recruited to this study had oropharyngeal, gastric and/or stool samples available. The relationships between microbial communities across the aerodigestive tract were described by analyzing within- and between-patient beta diversities and identifying taxa which are exchanged between aerodigestive sites within patients. These relationships were then compared in patients with and without aspiration to evaluate the effect of aspiration on the aerodigestive microbiome., Results: Within all patients, lung, oropharyngeal and gastric microbiomes overlap. The degree of similarity is the lowest between the oropharynx and lungs (median Jensen-Shannon distance (JSD) = 0.90), and as high between the stomach and lungs as between the oropharynx and stomach (median JSD = 0.56 for both; p = 0.6). Unlike the oropharyngeal microbiome, lung and gastric communities are highly variable across people and driven primarily by person rather than body site. In patients with aspiration, the lung microbiome more closely resembles oropharyngeal rather than gastric communities and there is greater prevalence of microbial exchange between the lung and oropharynx than between gastric and lung sites (p = 0.04 and 4x10-5, respectively)., Conclusions: The gastric and lung microbiomes display significant overlap in patients with intact airway protective mechanisms while the lung and oropharynx remain distinct. In patients with impaired swallow function and aspiration, the lung microbiome shifts towards oropharyngeal rather than gastric communities. This finding may explain why antireflux surgeries fail to show benefit in pediatric pulmonary outcomes., Competing Interests: The authors have declared that no competing interests exist.

The number of patients with pneumonia has been increasing as the population ages, and most fatal pneumonia cases are the elderly with aspiration pneumonia. Although aspiration pneumonia leads to poor short- and long-term prognosis, there have been no practical ways to diagnose it precisely. Persistent subclinical aspiration without any subjective symptoms is problematic in clinical practice in patients with aspiration pneumonia, and physicians can only use aspiration risks such as brain infarction to diagnose aspiration pneumonia. Anaerobes have been believed to be major causative pathogens in aspiration pneumonia, based on data from the 1970's. In relation to these data, Marik insisted that there is a possible overestimation of anaerobes because 1) the sampling of microbiologic specimens was in the late phase in the course of the illness, especially frequently after developing complications such as abscesses, necrotizing pneumonia, or empyema thoracis; 2) the organisms recovered by percutaneous transtracheal aspiration (PTA) sampling could have been contaminated by the aspiration of oropharyngeal flora during the PTA procedure or colonized in the trachea; and 3) many of the patients had chronic alcoholism or were under general anesthesia. In addition, 4) oral care was not common in the 1970s, and 5) the patients in these reports were relatively young. Molecular biological approaches using the 16S ribosomal RNA (rRNA) gene have recently been used, and have enabled us to detect more exact pathogens compared to conventional bacterial culture. Using the method with the detection of the 16S rRNA gene, we evaluated the bacterial phylotypes in bronchoalveolar lavage fluid in patients with aspiration pneumonia and found that oral streptococci were the most detected phylotypes (31.0%), while anaerobes were only 6.0%. Our results suggest that oral streptococci are important, and anaerobes may have been overestimated as causative pathogens in patients with aspiration pneumonia.

Background: Increased amount of tongue coating has been reported to be associated with increased bacteria count in the saliva and aspiration pneumonia in elderly people. However, the implications of tongue coating for prevention of postoperative complications in patients undergoing major oncologic or cardiac surgery has not been well documented. The purpose of this study is to investigate the number of bacteria on the tongue before and after surgery and factors affecting it., Methods: Fifty-four patients who underwent oncologic or cardiac surgery under general anesthesia at Nagasaki University Hospital were enrolled in the study. Various demographic, tumor-related, treatment-related factors, and the number of bacteria on the tongue and in the saliva were examined, and the relationship among them was analyzed by Mann-Whitney U test, Spearman rank correlation coefficient, or multiple regression., Results: Before surgery, no significant factors were correlated with the number of bacteria on the tongue, and there were no relationship between bacteria count on the tongue and that in the saliva. On the next day after surgery, bacteria on the tongue increased, and sex, periodontal pocket depth, feeding condition, dental plaque, blood loss, and bacteria in the saliva were correlated with bacteria on the tongue by a univariate analysis. A multivariate analysis showed that feeding condition, and amount of dental plaque were correlated with the number of bacteria., Conclusions: Increased number of bacteria on the tongue was associated with feeding condition and amount of dental plaque. Further studies are necessary to clarify the clinical significance of dental coating in perioperative oral management of patients undergoing oncologic or cardiac surgery.

Background: Aspiration pneumonia is a common problem in older people with high mortality and increasing prevalence., Objective: The aims of this paper were to systematically review the literature on the antibacterial treatment of aspiration pneumonia in elderly patients and identify the microbiology of aspiration pneumonia., Materials and Methods: EMBASE, MEDLINE, and Cochrane databases were systematically searched for studies that examined the clinical efficacy of antibiotic treatment in elderly patients with aspiration pneumonia. Information on study design, antibiotic treatment, study population, participants, microbiology, clinical outcomes, adverse events, and mortality was recorded., Results: There were no definitive clinical trials, placebo-controlled trials, or meta-analyses. Of the eight studies selected for inclusion in the review, the majority utilized and/or compared broad-spectrum antibiotics. No specific antibacterial agent had evidence of superior efficacy. Broad-spectrum antibiotics resulted in the emergence of multiresistant organisms. Anaerobic bacteria were infrequently isolated, suggesting a less important role in the pathogenesis of aspiration pneumonia., Conclusion: There is limited evidence with regard to the use of antibiotics in older patients with aspiration pneumonia. Research providing an evidence base for the treatment of aspiration pneumonia in older people is required., Competing Interests: Disclosure The authors report no conflicts of interest in this work.

OBJECTIVE To investigate incidence, clinical features, potential risk factors, and prognostic indicators for aspiration pneumonia in Pugs, French Bulldogs, and Bulldogs. DESIGN Retrospective, observational study. ANIMALS 41 brachycephalic dogs with aspiration pneumonia. PROCEDURES Medical records of a veterinary referral hospital were retrospectively searched to identify Pugs, French Bulldogs, and Bulldogs treated for aspiration pneumonia between 2006 and 2015. Signalment, clinical data, and outcomes were recorded. Variables of interest were analyzed for statistical associations with outcome. Incidence of aspiration pneumonia for the population of interest was compared with that for all other dog breeds and for the general hospital population of dogs during the study. RESULTS 41 of 2,141 (1.91%) dogs of the selected brachycephalic breeds and 396 of 80,137 (0.49%) dogs overall had a diagnosis of aspiration pneumonia. Relative risk of the disease in the population of interest was 3.77 times that for all other breeds. Median age at disease onset was greater for Pugs (83 months) than for French Bulldogs (8 months) and Bulldogs (6 months). History of gastrointestinal signs was the most commonly observed preidentified risk factor (27/41 [66%]) in these breeds. Neurologic disease was significantly more common in Pugs than in French Bulldogs and Bulldogs. On univariate analysis, increased age, male sex, obtundation, hypoalbuminemia, azotemia, and high liver enzyme activities were associated with nonsurvival; on logistic regression, increased age was associated with nonsurvival. CONCLUSIONS AND CLINICAL RELEVANCE Age at onset and presence of other risk factors for aspiration pneumonia may vary among brachycephalic dog breeds. Prospective studies are needed to determine common risk factors and prognostic indicators for aspiration pneumonia in the larger population of brachycephalic dogs.

Purpose: Hypervirulent Klebsiella pneumoniae (hvKp) has emerged as a leading cause of severe community-acquired pneumonia, liver abscess and disseminated infection in the Far East. Data regarding the incidence, clinical features and microbiological characteristics related to hvKp infections in the Western world are scarce., Methodology: The incidence, clinical features and microbiological characteristics of hvKp infections were investigated through a 5-year survey conducted in a single French intensive care unit. K. pneumoniae strains were screened for hypermucoviscosity based on a string test. Multilocus sequence typing and multiplex PCR analysis targeting virulence genes were performed on string test-positive strains., Results: Over a 53-month period, a total of 59 infections due to K. pneumoniae were identified including 26 community-onset infections. Twelve hvKp infections were documented, accounting for 46.1 % of community-acquired K. pneumoniae. Community-acquired pneumonia (n=6), aspiration pneumonia (n=4) and liver abscess (n=2) represented initial sites and mode of infection. Compared to non-hvKp infections, patients with hvKp infections displayed higher rates of multi-organ failure (83.3 % vs 35.7 %; P=0.04), but mortality rates were not different (50 % vs 35 %; P=0.71). Strains K1/ST23 (n=5) and K2/ST86 (n=5) predominated. All hvKp strains displayed wild-type susceptibility., Conclusion: hvKp represent a potentially underestimated cause of fatal infections in the Western world.

Murine infection models are critical for understanding disease pathogenesis and testing the efficacy of novel therapeutics designed to combat causative pathogens. Infectious pneumonia is among the most common infections presented by patients in the clinic and thus warrants an appropriate in vivo model. Typical pneumonia models use intranasal inoculation, which deposits excessive organisms outside the lung, causing off-target complications and symptoms, such as sinusitis, gastritis, enteritis, physical trauma, or microparticle misting to mimic aerosol spread more typical of viral, tuberculous, or fungal pneumonia. These models do not accurately reflect the pathogenesis of typical community- or healthcare-acquired bacterial pneumonia. In contrast, this murine model of oropharyngeal aspiration pneumonia mimics the droplet route in healthcare-acquired pneumonia. Inoculating 50 µL of the bacteria suspension into the oropharynx of anesthetized mice causes reflexive aspiration, which results in pneumonia. With this model, one can examine the pathogenesis of pneumonia-causing pathogens and new treatments to combat these diseases.

Aspiration pneumonia has a high incidence in hospitalized patients with community-acquired pneumonia and results in high mortality rates. We aimed to evaluate microbiology and assess prognostic factors of aspiration pneumonia in the setting of a tertiary hospital pulmonology department. Community-acquired (CAAP) and healthcare-associated aspiration pneumonia (HCAAP) cases hospitalized over a period of a year were prospectively followed. Demographic, clinical, biological and radiological data were recorded at admission, while sputum, tracheal aspirates or bronchial washing samples were collected within 48 hours of admission. During hospital stay, therapeutic and supportive measures and resulting complications were recorded. Regression analysis was applied to find statistically significant prognostic factors. The sample consisted of 70 patients (67.1% men); 55.7% of them presented as HCAAP; 94.3% had positive culture of lower respiratory tract specimens with isolation of 115 pathogens, 47 of which were multidrug- or extensively drug-resistant. The most common pathogens were Pseudomonas aeruginosa (37.1%), Klebsiella pneumoniae (27.1%), Staphylococcus aureus (25.7%) and Acinetobacter baumannii (20%). Empiric antimicrobial therapy was combination therapy in 70% and included antipseudomonal and MRSA-targeted antibiotics in 61.4% and 11.4%, respectively. Patients in the HCAAP group had a higher rate of antibiotics usage in the previous trimester, more frequent isolation of resistant strains and were more likely to receive inadequate empiric treatment than those in the CAAP group. In-hospital mortality was 52.2%; no difference between groups was noted. Independent factors of increased mortality were older age (p=0.004), low serum albumin levels (p=0.039), increased radiological involvement (p=0.050) and ineffective initial therapy (p=0.001). We concluded that patients hospitalized for aspiration pneumonia have frequent contact with healthcare services and acquire multidrug-resistant Gram-negative bacteria. Empiric therapy should target these specific microorganisms as its success determines the prognosis.

Background: Clinical practice guidelines for nursing- and healthcare-associated pneumonia (NHCAP) were developed for pneumonia caused by drug-resistant bacteria and pneumonia in elderly patients, particularly aspiration pneumonia. The identification of pathogenic bacteria and implementation of efforts to prevent the recurrence of aspiration pneumonia are very important in clinical practice. This study examined the extent to which clinicians have established bacteriological testing and recurrence prevention efforts for NHCAP and aspiration pneumonia., Methods: Questionnaire surveys were mailed to the heads of internal medicine and respiratory medicine departments at 2490 Japanese hospitals. The questionnaire evaluated bacteriological testing for NHCAP or aspiration pneumonia and prevention of the recurrence of aspiration pneumonia., Results: A total of 350 hospitals responded. These hospitals were grouped on the basis of whether a pulmonologist provided medical care for aspiration pneumonia and whether the hospital employed an infectious disease specialist. For hospitals in which pulmonologists treated aspiration pneumonia, the response rates for "is done in nearly all cases" were 70.0%, 84.7%, 31.6%, and 48.9% for sputum gram staining, sputum culture tests, blood culture tests, and pneumococcal vaccination, respectively. In hospitals that employed an infectious disease specialist, the response rates for "is done in nearly all cases" were 72.8% and 41.3% for sputum gram staining and blood culture tests, respectively. Recurrence prevention for aspiration pneumonia (other than pneumococcal vaccination) was not actively implemented., Conclusions: Sputum gram staining, sputum culture tests, and other bacteriological tests were implemented quite actively. However, physicians who treat aspiration pneumonia should implement efforts to prevent pneumonia recurrence more actively., (Copyright © 2017 The Japanese Respiratory Society. Published by Elsevier B.V. All rights reserved.)

The association between achalasia and no tuberculosis mycobacterial   lung infection is well described in the literature. MycobactériumFortuitum is often responsible, and the clinical's presentation   is an aspiration pneumonia resistant to usual antibiotic therapy. We report the case of a 15 year-old patient with the history of Allgrove syndrome. The chest imaging showed right lung congestion; the diagnosis was bacteriological and MycobactériumFortuitum resistant to rifampicin, isoniazid, pyrazinamide and ethambutol was isolated. The patient was treated by the association cotrimoxazole, ciprofloxacin and clarithromycin for 12 months and the clinical, radiological and bacteriological outcomes were favorable. To prevent the recurrence the patient benefited from a cardiomyotomy.

The aim of this study was to detect possible associations between respiratory pathogens from tracheal aspirate and oral biofilm samples in intubated patients in an intensive care unit (ICU), and to identify the most common respiratory pathogens in oral biofilm, particularly in patients that developed ventilator-associated pneumonia (VAP). Two oral biofilm samples were collected from the tongue of intubated patients (at admission and after 48 hours) and analyzed by culture with the Antibiotic Sensitivity Test. The results from the tongue biofilm samples were compared with the tracheal secretions samples. A total of 59.37% of patients exhibited the same species of pathogens in their tracheal aspirate and oral biofilm, of which 8 (42.1%) developed VAP, 10 (52.63%) did not develop pneumonia and one (5.26%) had aspiration pneumonia. There was a statistically significant association between presence of microorganisms in the tracheal and mouth samples for the following pathogens: Klebsiella pneumoniae, Candida albicans, Pseudomonas aeruginosa, Enterobacter gergoviae, Streptococcus spp and Serratia marcescens (p < 0.05). Pathogens that are present in tracheal aspirates of intubated patients can be detected in their oral cavity, especially in those who developed VAP or aspiration pneumonia. Thus, the results indicate that an improved oral care in these patients could decrease ICU pneumonia rates.

Aim: Data on the causative pathogens and optimal empirical therapy of aspiration pneumonia in children are limited. This study sought to describe the bacteriology of aspiration pneumonia in hospitalised children with a high aspiration risk., Methods: Respiratory tract specimens were prospectively collected using the induced sputum technique from children with a high aspiration risk who were hospitalised for aspiration pneumonia in a tertiary paediatric medical centre from 2009 to 2014. Clinical, microbiological and treatment data were recorded and analysed for each admission., Results: The cohort comprised 50 children with 235 hospital admissions. Of the 183 respiratory tract cultures performed, 110 were positive for bacteria, with 169 isolates, mostly Gram-negative. The most common Gram-negative pathogen was Pseudomonas aeruginosa. If patients had Pseudomonas aeruginosa isolation, the risk of them having the pathogen again was 81%. The multivariate analysis showed that the use of antibiotic prophylaxis and number of hospitalisations were significantly associated with Pseudomonas aeruginosa isolation., Conclusion: Gram-negative bacilli, especially Pseudomonas aeruginosa, were the major causative agents of paediatric aspiration pneumonia in our study. Empiric antipseudomonas treatment should be considered, particularly in patients who are receiving antibiotic prophylaxis, have experienced recurrent hospitalisations or with previous respiratory cultures that showed Pseudomonas aeruginosa isolation., (©2016 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.)

Tropheryma whipplei, the causative bacterium of Whipple's disease, can cause acute pneumonia. We performed a case-control study including patients with T. whipplei in bronchoalveolar lavages (BALs) and controls in order to compare patients' clinical statuses. We tested T. whipplei PCR from January 2013 to December 2014, in all the 1438 BALs in Marseille, France. Controls were hospitalized in the same unit during the same period and were comparable in age and sex. Eighty-eight BALs (6.1%) were positive for T. whipplei and 58 patients had pneumonia. Sixty-four patients were male with a mean age of 50.5 years. T. whipplei was commonly associated with aspiration pneumonia (18/88 patients compared with 6/88 controls, p 0.01) and was detected as a unique pathogen in nine cases. Overall, no difference was observed regarding immunocompromised status. Nevertheless, the six AIDS-infected patients in the T. whipplei group had a significantly lower CD4 level than the five AIDS-infected patients in the control group (49 vs. 320/mm 3 , p 0.01); in addition, five patients were treated with tumour necrosis factor alpha inhibitors (including three treated by monocolonal antibodies and two with soluble receptor) compared with none of the controls (p 0.03). Pneumocystis jirovecii was frequently associated with the T. whipplei group (7/88 vs. 0/88 in control group), Pseudomonas aeruginosa was only detected in the control group (8/88). This study adds evidence for a causative role of T. whipplei in pneumonia. In the future, an experimental model of pneumonia induced by T. whipplei will prove its role in pneumonia., (Copyright © 2016 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Although community-acquired pneumonia remains a major public health problem, murine models of bacterial pneumonia have recently facilitated significant preclinical advances in our understanding of the underlying cellular and molecular pathogenesis. In vivo mouse models capture the integrated physiology and resilience of the host defense response in a manner not revealed by alternative, simplified ex vivo approaches. Several methods have been described in the literature for intrapulmonary inoculation of bacteria in mice, including aerosolization, intranasal delivery, peroral endotracheal cannulation under 'blind' and visualized conditions, and transcutaneous endotracheal cannulation. All methods have relative merits and limitations. Herein, we describe in detail a non-invasive, technically non-intensive, inexpensive, and rapid method for intratracheal delivery of bacteria that involves aspiration (i.e., inhalation) by the mouse of an infectious inoculum pipetted into the oropharynx while under general anesthesia. This method can be used for pulmonary delivery of a wide variety of non-caustic biological and chemical agents, and is relatively easy to learn, even for laboratories with minimal prior experience with pulmonary procedures. In addition to describing the aspiration pneumonia method, we also provide step-by-step procedures for assaying the subsequent in vivo pulmonary innate immune response of the mouse, in particular, methods for quantifying bacterial clearance and the cellular immune response of the infected airway. This integrated and simple approach to pneumonia assessment allows for rapid and robust evaluation of the effect of genetic and environmental manipulations upon pulmonary innate immunity.

Background: Aspiration pneumonia has been a growing interest in an aging population. Anaerobes are important pathogens, however, the etiology of aspiration pneumonia is not fully understood. In addition, the relationship between the patient clinical characteristics and the causative pathogens in pneumonia patients with aspiration risk factors are unclear. To evaluate the relationship between the patient clinical characteristics with risk factors for aspiration and bacterial flora in bronchoalveolar lavage fluid (BALF) in pneumonia patients, the bacterial floral analysis of 16S ribosomal RNA gene was applied in addition to cultivation methods in BALF samples., Methods: From April 2010 to February 2014, BALF samples were obtained from the affected lesions of pneumonia via bronchoscopy, and were evaluated by the bacterial floral analysis of 16S rRNA gene in addition to cultivation methods in patients with community-acquired pneumonia (CAP) and healthcare-associated pneumonia (HCAP). Factors associated with aspiration risks in these patients were analyzed., Results: A total of 177 (CAP 83, HCAP 94) patients were enrolled. According to the results of the bacterial floral analysis, detection rate of oral streptococci as the most detected bacterial phylotypes in BALF was significantly higher in patients with aspiration risks (31.0 %) than in patients without aspiration risks (14.7 %) (P = 0.009). In addition, the percentages of oral streptococci in each BALF sample were significantly higher in patients with aspiration risks (26.6 ± 32.0 %) than in patients without aspiration risks (13.8 ± 25.3 %) (P = 0.002). A multiple linear regression analysis showed that an Eastern Cooperative Oncology Group (ECOG) performance status (PS) of ≥3, the presence of comorbidities, and a history of pneumonia within a previous year were significantly associated with a detection of oral streptococci in BALF., Conclusions: The bacterial floral analysis of 16S rRNA gene revealed that oral streptococci were mostly detected as the most detected bacterial phylotypes in BALF samples in CAP and HCAP patients with aspiration risks, especially in those with a poor ECOG-PS or a history of pneumonia.

Introduction: Inadequate oral care has been implicated in the development of aspiration pneumonia in frail geriatric patients and is a major cause of mortality, due to the colonisation of microbes in vulnerable patients. This type of pneumonia has been associated with an increase in respiratory pathogens in the oral cavity. The aim of this study was to evaluate the effects of chlorhexidine compared to routine oral care in edentulous geriatric inpatients., Methods: A double-blind, parallel-group randomised controlled trial was carried out. The intervention group received oral care with chlorhexidine 0.2%, while the control group received routine oral care with thymol. Nurses provided oral care with assigned solutions of 20 mL once daily over seven days. Oral cavity assessment using the Brief Oral Health Status Examination form was performed before each oral care procedure. Data on medication received and the subsequent development of aspiration pneumonia was recorded. An oral swab was performed on Day 7 to obtain specimens to test for colonisation., Results: The final sample consisted of 35 (control) and 43 (intervention) patients. Chlorhexidine was effective in reducing oral colonisation compared to routine oral care with thymol (p < 0.001). The risk of oral bacterial colonisation was nearly three times higher in the thymol group compared to the chlorhexidine group., Conclusion: The use of chlorhexidine 0.2% significantly reduced oral colonisation and is recommended as an easier and more cost-effective alternative for oral hygiene., (Copyright: © Singapore Medical Association.)

Purpose: Children with cerebral palsy (CP) are at an increased risk for aspiration, and subsequent pneumonia or pneumonitis. Pneumonia is a common cause of hospital admission, intensive care unit (ICU) admission, and death in patients with CP, and may disproportionately contribute to mortality. The role of respiratory microflora is unknown. This study examined the relationship between respiratory infections with Gram-negative bacteria (GNB), particularly Pseudomonas aeruginosa, and the frequency/severity of pneumonia hospitalization., Methods: Retrospective chart review of 69 patients with CP and hospitalization for pneumonia. Eligible patients required hospitalization for bacterial pneumonia, at least one respiratory culture, and fulfillment of Bax definition of CP. Group assignment was based on respiratory culture. Charts were analyzed for comorbid illness, hospitalization demographics, and disease severity., Results: Children with isolation of P. aeruginosa or other GNB had increased frequency of ICU admission (77.4, 65.1, vs. 26.9 %, respectively, p < 0.01), intubation (45.2, 39.5 vs. 11.5 %, p = 0.02, p = 0.03 respectively), and large pleural effusions (37.5, vs. 0 %) than children without GNB. Children with isolation of GNB had more prolonged hospitalizations and were more likely to have multiple hospitalizations than those without GNB., Conclusion: Colonization with P. aeruginosa and other Gram-negative organisms in children with CP is associated with increased morbidity, prolonged hospitalization, and severity of pneumonia including need for PICU admission and intervention. Further research is required to determine causality, the role of antimicrobials active against Gram negative in pneumonia treatment, and the role of GNB eradication therapy in children with CP.

Inappropriate antimicrobial treatment could adversely affect the recovery of patients with aspiration pneumonia. We attempted to identify inappropriate antibacterial treatment and to determine the standard use of anti-methicillin-resistant Staphylococcus aureus (MRSA) drugs in aspiration pneumonia patients with MRSA-positive in sputum. Aspiration pneumonia patients with MRSA-positive sputum treated between January 2013 and May 2013 were included in this study to determine the risk factors for death during hospitalization. The relationship between anti-MRSA medicine use and death during hospitalization was also investigated. More than 10⁷ MRSA colony-forming units in sputum culture, creatinine clearance of less than 30 mL/min, and quinolone use were found to be risk factors for death during hospitalization. The death rate during hospitalization was significantly lower in cases a Geckler classification of 4 or 5 when anti-MRSA treatment was initiated soon after the culture was obtained. Therefore, we concluded that the use of quinolones as antibacterial treatment in aspiration pneumonia patients with MRSA-positive sputum should be avoided and that anti-MRSA treatment should be started in cases with good quality sputum cultures.

Unlabelled: We characterize and decipher the resistome and the virulence factors of Shewanella algae MARS 14, a multidrug-resistant clinical strain using the whole genome sequencing (WGS) strategy. The bacteria were isolated from the bronchoalveolar lavage of a hospitalized patient in the Timone Hospital in Marseille, France who developed pneumonia after plunging into the Mediterranean Sea., Results: The genome size of S. algae MARS 14 was 5,005,710 bp with 52.8% guanine cytosine content. The resistome includes members of class C and D beta-lactamases and numerous multidrug-efflux pumps. We also found the presence of several hemolysins genes, a complete flagellum system gene cluster and genes responsible for biofilm formation. Moreover, we reported for the first time in a clinical strain of Shewanella spp. the presence of a bacteriocin (marinocin)., Conclusion: The WGS analysis of this pathogen provides insight into its virulence factors and resistance to antibiotics.

Aim: Oral bacteria, which are a source of infection for aspiration pneumonia, were examined in frail older adults with the aim of establishing a standard bacteria count that indicates the risk of pneumonia onset in this group., Methods: A survey of bacteria count in the saliva using a simple instrument for measurement of the number of oral bacteria, along with factors including swallowing function and nutritional status, was carried out in 691 elderly individuals requiring care (137 men; mean age 82.6 ± 8.3 years; 554 women; mean age 88.0 ± 7.1 years; total mean age 86.7 ± 7.8 years) at 16 nursing homes in Japan. All participants gave their consent for inclusion in the present study. During a 6-month follow-up period, participants who developed pneumonia were identified, and relationships between the factors measured at the start of the period and pneumonia onset were examined., Results: During the 6-month follow-up period, 33 participants (4.8%; 5 men, 28 women; mean age 88.3 ± 7.4 years) developed pneumonia. Pneumonia onset was significantly associated with reduced activities of daily living, swallowing dysfunction and undernourishment. Logistic regression analysis identified a saliva bacteria count of 10(8.5)  colony-forming units/mL as an independent explanatory factor for pneumonia onset (P = 0.012, RR = 3.759)., Conclusions: Oral bacteria count of 10(8.5)  colony-forming units/mL saliva in an elderly person requiring care was identified as a risk factor for pneumonia onset., (© 2014 Japan Geriatrics Society.)

Here, we report a case of pneumonia possibly caused by the aspiration of runoff water containing Chromobacterium haemolyticum. A 69-year-old man became intoxicated with alcohol, fell into a ditch, and lost consciousness after suffering a blow to the head. The lower half of his body was completely paralyzed because of damage to his spinal cord, and he aspirated runoff water from the ditch. Chest computed tomography scans revealed consolidation in the right upper lobe and bilateral lower lobes. A sputum culture detected gram-negative bacteria that was identified as C. haemolyticum. Antibacterial chemotherapy was initiated, and the clinical course was favorable. To the best of our knowledge, this is the first report of C. haemolyticum pneumonia in the literature.

Microaspiration of subglottic secretions through channels formed by folds in high volume-low pressure poly-vinyl chloride cuffs of endotracheal tubes is considered a significant pathogenic mechanism of ventilator-associated pneumonia (VAP). Therefore a series of prevention measures target the avoidance of microaspiration. However, although some of these can minimize microaspiration, benefits in terms of VAP prevention are not always obvious. Polyurethane-cuffed endotracheal tubes successfully reduce microaspiration but high quality data demonstrating VAP rate reduction are lacking. An analogous conclusion can be made regarding taper-shaped cuffs compared with classic barrel-shaped cuffs. More clinical data regarding these endotracheal tube designs are needed to demonstrate clinical value in addition to in vitro-based evidence. The clinical usefulness of endotracheal tubes developed for subglottic secretions drainage is established in multiple studies and confirmed by meta-analysis. Any change in cuff design will fail to prevent microaspiration if the cuff is insufficiently inflated. At least one well-designed trial demonstrated that continuous cuff pressure monitoring and control decrease the risk of VAP. Gel lubrication of the cuff prior to intubation temporarily hampers microaspiration through sludging the channels formed by folds in high volume-low pressure cuffs. As the beneficial effect of gel lubrication is temporarily, its potential to reduce VAP risk is probably nonsignificant. A minimum positive end-expiratory pressure of at least 5 cmH2O can be recommended as it reduces the risk of microaspiration in vitro and in vivo. One randomized controlled study demonstrated a reduced risk of VAP in patients ventilated with PEEP (5-8 cmH2O). Regarding head-of-bed elevation, it can be recommended to avoid supine positioning. Whether a 45° head-of-bed elevation is to be preferred above 25-30° head-of-bed elevation remains unproven. Finally, the routine monitoring of gastric residual volumes in mechanically ventilated patients receiving enteral nutrition cannot be recommended.

Poor oral hygiene has been suggested to be a risk factor for aspiration pneumonia in the institutionalized and disabled elderly. Control of oral biofilm formation in these populations reduces the numbers of potential respiratory pathogens in the oral secretions, which in turn reduces the risk for pneumonia. Together with other preventive measures, improved oral hygiene helps to control lower respiratory infections in frail elderly hospital and nursing home patients., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Lactobacilli are low-virulence, commensal organisms of the gastrointestinal and genitourinary tracts and are commonly used as "probiotic supplements." Herein, we describe an episode of respiratory syncytial virus (RSV) bronchiolitis with bacterial superinfection secondary to administration of Lactobacillus rhamnosus in an 11-month-old female with trisomy 21., (Copyright © 2014, American Society for Microbiology. All Rights Reserved.)

Background: Incidence of aspiration pneumonia in hospital-acquired pneumonia and community-acquired pneumonia is high; however, many features of this disease remain imprecise. Our objective was to characterize the microbial etiology and their antibiotic resistance and to determine the prognostic factors in aspiration pneumonia among patients admitted to a respiratory intensive care unit (RICU)., Methods: A prospective survey was conducted in 112 patients exhibiting hospital-or community-acquired aspiration pneumonia in the RICU of a provincial general hospital from 2010-2012. Bronchoalveolar lavage sampling was collected, and then followed by standard culture and drug-sensitive test. Risk factors were analyzed by multivariate logistic analysis., Results: One hundred twenty-eight strains were isolated in 94 patients, gram-negative bacilli (57.8%) was the predominant cultured microorganism, followed by fungus (28.9%) and gram-positive cocci (13.3%). The 5 main isolated bacteria demonstrated high and multiantibiotic resistance. The crude overall mortality was 43.8%, 50%, and 40%, respectively, in hospital- and community-acquired aspiration pneumonia group. Multivariate logistic analysis identified age older than 65 years, use of inotropic support, and ineffective initial therapy as independent risk factors of poor outcome., Conclusions: The predominant pathogenic bacteria of aspiration pneumonia in patients admitted to an RICU were antibiotic-resistant bacteria, and effective initial supportive management secured better prognosis., (Copyright © 2013 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.)

Nursing- and healthcare-associated pneumonia (NHCAP) has been proposed by the Japanese Respiratory Society as a new category of pneumonia considering the characteristics of the Japanese medical care environment. It is necessary to ascertain the epidemiology and clinical outcomes of NHCAP. A prospective study was conducted of patients with pneumonia who were hospitalized at our hospital from August 2011 to July 2012. We compared 192 cases of NHCAP with 114 cases of community-acquired pneumonia (CAP). Compared with CAP, NHCAP had a higher disease severity, higher 30-day mortality rate (10.9 vs. 3.5 %, P = 0.022), and longer length of hospital stay (median, 12 vs. 8 days, P < 0.001). Streptococcus pneumoniae was the most frequent causative pathogen in both NHCAP and CAP (33.9 vs. 34.8 %, P = 0.896). The incidence of atypical pathogens in NHCAP was low (1.7 %). Multidrug-resistant (MDR) pathogens were isolated more frequently in NHCAP than in CAP, but there was no significant difference (11.0 vs. 4.5 %, P = 0.135). Among 192 NHCAP patients, 122 (63.5 %) were aspiration pneumonia. Aspiration pneumonia was associated with poor outcomes and was considered a major characteristic of NHCAP. Our study suggested that many patients with NHCAP do not need broad-spectrum antibiotic therapy targeting MDR pathogens. Excess mortality in NHCAP patients is the result of patient backgrounds or disease severity rather than the presence of MDR pathogens.

A 7-year-old spayed female German Wirehaired Pointer was presented with difficulty breathing after being found seizing in a water-filled drainage ditch while out hunting. Aspirates from a tracheal wash contained numerous degenerate neutrophils, fewer macrophages, some of which contained basophilic debris, low numbers of extracellular diatoms, and a single intracellular short bacterial rod. As the dog continued to clinically decline and could not be weaned from oxygen support, the owners chose euthanasia. The major necropsy finding was a severe granulomatous bronchopneumonia that was likely due to aspiration of foreign material based on the microscopic presence of plant-like material, bi-refringent crystalline material, non-cellular debris, and occasional fungal structures. Diatoms are a class of algae that live primarily in water. Diatom analysis has been used, with some controversy, in human forensics to assist in documenting drowning as the cause of death. In this case, given the clinical history, the presence of diatoms and inflammation in the tracheal wash were interpreted as a likely result of the aspiration of surface water. To our knowledge, this is the first reported case of diatoms observed in a cytologic specimen in a nonhuman mammal with aspiration pneumonia., (© 2013 American Society for Veterinary Clinical Pathology.)

Objective: To determine whether acid aspiration provokes the development of multidrug-resistant Acinetobacter baumannii (MDRAB) pneumonia in its host., Methods: Groups of mice were inoculated intratracheally (IT) with 50 μl of 0.1N HCl and 1 × 10(8) colony-forming units (CFU) Ab396 (A+Ab group), or 50 μl of 0.1N HCl and 20 μl of 0.9% saline (A+S group), or 20 μl of 0.9% saline and 1 × 10(8) CFU of Ab396 (S+Ab group), or 50 μl of 0.9% saline and 20 μl of 0.9% saline (S+S group). Cytokines, bacterial loads in the bronchoalveolar lavage fluid (BALF), lung permeability, histopathology of the lungs, and survival rates were evaluated., Results: Only the A+Ab mice developed extensive Ab396 pneumonia and had significantly elevated bacterial loads, increased lung leakage, and lower levels of tumor necrosis factor alpha (TNF-α) compared with the other three groups (p<0.05, Mann-Whitney U-test). Moreover, a strong synergistic effect (p<0.05, two-way analysis of variance) was observed between the acid induction and Ab396 infection, resulting in lung injury and an unfavorable survival outcome., Conclusions: Lung injury caused by acid aspiration provoked secondary MDRAB pneumonia; also synergistic effects between acid aspiration and Ab396 infection resulted in a detrimental outcome in the infected mice., (Copyright © 2013 International Society for Infectious Diseases. All rights reserved.)

Anaerobic bacteria are infrequent pulmonary pathogens, and, even then they are, they are almost never recovered due to the need for specimens uncontaminated by the upper airway flora and failure to do adequate anaerobic bacteriology. These bacteria are relatively common in selected types of lung infections including aspiration pneumonia, lung abscess, necrotizing pneumonia and emphyema. Preferred antibiotics for these infections based on clinical experience are clindamycin and any betalactam-betalactamase inhibitor., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Many survivors of the tsunami that occurred following the Great East Japan Earthquake on March 11, 2011, contracted a systemic disorder called "tsunami lung," a series of severe systemic infections following aspiration pneumonia caused by near drowning in the tsunami. Generally, the cause of aspiration pneumonia is polymicrobial, including fungi and aerobic and anaerobic bacteria, but Aspergillus infection is rarely reported. Here we report a case of tsunami lung complicated by disseminated aspergillosis, as diagnosed during autopsy.

Klebsiella pneumoniae is an important causative bacterium of aspiration pneumonia in many elderly patients. We retrospectively investigated the clinical effects of the early treatment of aspiration pneumonia and background factors in 24 patients from whom Klebsiella pneumoniae was isolated. Sulbactam/ampicillin (SBT/ABPC) was selected for early treatment in 12 of the 24 patients diagnosed with aspiration pneumonia, and tazobactam/piperacillin (TAZ/PIPC) was selected for the other patients. The effective rates and success rates of early treatment were significantly higher in the TAZ/PIPC group than in the SBT/ABPC group (p = 0.003 and 0.027, respectively). Although no significant difference was noted because of the limited number of cases, the survival rates after 30 days were 91.7 and 58.3 % in the TAZ/PIPC and SBT/ABPC groups, respectively. Several bacteria isolated with Klebsiella pneumoniae were resistant bacteria, such as methicillin-resistant Staphylococcus aureus or Pseudomonas aeruginosa, and no anaerobe or extended-spectrum β-lactamase-producing Klebsiella pneumoniae was isolated. Thirteen and 11 of the 24 cases were classified as healthcare-associated pneumonia (HCAP) and hospital-acquired pneumonia (HAP), respectively, with no case classified as community-acquired pneumonia (CAP). As population aging progresses, the frequency of aspiration pneumonia classified as HCAP will increase. To cover anaerobes, it is necessary to select antibacterial drugs, such as TAZ/PIPC, for early treatment in consideration of resistant gram-negative bacteria to improve the outcome, and not drugs with weak activity against these bacteria.

Robinsoniella peoriensis has recently been identified as a Gram-positive, spore-forming, anaerobic rod originally recovered from swine manure storage pits. To date, 6 cases of R. peoriensis infection have been reported, including 2 cases of bacteremia, 1 of abdominal fluid collection, and 3 of wound infection. In the present study, we report a 76-yr-old man with R. peoriensis bacteremia who developed aspiration pneumonia. Gram staining of a purified colony revealed Gram-positive, rod-shaped bacteria. Biochemical identification using API 20 A (bioMérieux, France) indicated presence of Clostridium spp. We performed both 500-bp and full-gene sequencing of 16S rRNA of the isolate. The sequence was analyzed with MicroSeq ID 16S rRNA Library v2.0 (Applied Biosystems, USA), GenBank Basic Local Alignment Search Tool (BLAST) (http://www.ncbi.nlm.nih.gov/genbank), and EzTaxon database v2.1 (http://www.eztaxon.org). The 500-bp 16S rRNA sequence of the blood culture isolate showed 99.16-99.79% similarity with R. peoriensis and the full-gene 16S rRNA sequence showed 98.87-99.50% similarity with R. peoriensis. The organism was confirmed as R. peoriensis by using all of the mentioned databases except for MicroSeq, which did not include the RNA sequence of this bacterium. This case suggests that identification of R. peoriensis might be challenging in clinical laboratories with no access to molecular methods, as certain commercial identification systems may not identify, or may misidentify, this organism. To the best of our knowledge, this is the first report of the isolation of R. peoriensis in Korea.

Adjunctive corticosteroid treatment to reduce excessive local inflammatory response in pneumonia is controversial. To study the effects of an early local adjunct dexamethasone treatment on the course of pneumonia and inflammatory/cytokine response, mice were intratracheally inoculated with live Porphyromonas gingivalis and treated with either clindamycin (C), dexamethasone (D), C+D combination, or were not treated (Pg). Six mice from each group were euthanized at 6, 24, 72, and 168 hours after inoculation. Levels of tumor necrosis factor (TNF)-α, soluble TNF-α receptors (sTNFR1 and sTNFR2), interleukin (IL)-1β, and IL-6 in the serum and lung-homogenate supernatant were determined. Lung samples were histopathologically assessed and all findings compared to those found in 24 sham-inoculated mice (phosphate-buffered saline [PBS]). Severe P. gingivalis-induced bronchopneumonia progressed from 24 hours, peaked at 72 hours, and resolved after 168 hours with changes in local and systemic cytokine levels. Clindamycin-treated mice developed only mild bronchopneumonia that resolved fast (72 hours) with an early (6-24 hours) normalization of local and systemic cytokine levels. Similar course of pneumonia and cytokine level changes were observed in mice treated with C+D, but later. Early (6-24 hours) local elevation of sTNFRs was observed in C and C+D groups of mice, whereas nontreated (Pg) mice had increased systemic sTNFRs. Severe bronchopneumonia with delayed resolution was observed in D-group mice, with an early local and systemic decrease in sTNFR1 and persistent elevation of local TNF-α. Clindamycin or a clindamycin-dexamethasone combination treatment significantly improves the course of P. gingivalis-aspiration pneumonia, but more so if clindamycin alone is used. A favorable course of pneumonia seems to be associated with an early elevation of sTNFRs and normalization of TNF-α.