Emerging evidence suggests some bacterial infections may be early signs of hidden cancers rather than random events. Yet this link remains under-recognized in practice, representing an often-missed diagnostic opportunity. Large registry studies show that certain infections are linked to a sharply increased short-term risk of cancer detection, with most of the excess diagnoses clustering in the first 6 months after the index episode. Key associations include the following: (i) anaerobic or gut-derived bacteremia with Bacteroides, Clostridium, Fusobacterium, or pks+Escherichia coli before colorectal neoplasm; (ii) Streptococcus gallolyticus/bovis bacteremia and colorectal neoplasm; (iii) cryptogenic Klebsiella pneumoniae liver abscess and pancreaticobiliary or colorectal cancer; (iv) non-resolving pneumonia and segmental collapse before lung cancer. Overall, short-term cancer detection risks range from about 3% after unselected Gram-negative bacteremia to ~8% or higher after cryptogenic liver abscess-similar to accepted thresholds that justify targeted cancer work-up. Even hidden tumors disrupt immunity, compromise barriers, and create conditions that favor microbial invasion. This review synthesizes evidence for the "sentinel infection phenotype"; outlines pathogen-specific associations, including their possible pathogenetic mechanisms; and proposes a practical diagnostic framework. Recognizing these infection signatures may enable earlier cancer detection and better outcomes.

China is experiencing a demographic shift as its population ages. The elderly population becomes increasingly susceptible to pneumonia. Pneumonia in the elderly is characterized by its insidious onset, rapid progression, multiple comorbidities, poor prognosis, and high morbidity and mortality. Physicians need to pay attention to developing more comprehensive diagnostic evaluations and treatment strategies, and ensuring personalized care to the greatest extent. In order to improve the prevention and management of pneumonia in elderly, this consensus incorporates the latest guidelines and consensus from both domestic and international sources. The latest progress in this research field is also included. The document addresses 17 clinical issues in a question-and-answer format and provides 13 recommendations on the etiology, pathogenesis, clinical diagnosis, treatment, and prevention of pneumonia in older adults. It provides reference for the prevention and treatment of pneumonia in elderly, improving their quality of life, reducing hospitalization and mortality, and promoting healthy aging. The specific recommendations are as follows.Recommendation 1:The main risk factors for pneumonia in the elderly include age (Recommended Level ⅠA), age-related systemic factors (such as poor physical condition, underlying diseases, and concomitant medications), and specific factors (specifically dysphagia and aspiration). The risk increases progressively with age (Recommended Level Ⅱ-1A).Recommendation 2:Pneumonia in elderly individuals often presents with an insidious onset and atypical respiratory symptoms, especially in super-elderly patients. Initially, symptoms may include fatigue, loss of appetite, and disturbance of consciousness. Moreover, elderly patients often have underlying conditions such as pulmonary, cardiovascular, and neurological disorders, which can lead to rapid deterioration, multiple complications and sequelae. Pneumonia-related laboratory parameters in the elderly lack typical characteristic changes (Recommended Level ⅢA). The high proportion of comorbidities significantly increases the risk of pneumonia, especially pneumonia caused by drug-resistant bacteria, and the likelihood of a worse prognosis in elderly patients (Recommended Level Ⅱ-2A). Neurological or psychiatric disorders and therapeutic drugs such as antipsychotic drugs increase the risk of pneumonia including aspiration pneumonia, necrotizing pneumonia, lung abscess, hypostatic pneumonia and atelectasis in elderly patients (Recommended Level Ⅱ-2B).Recommendation 3:For elderly patients with suspected pneumonia, chest CT should be performed as early as possible in cases of long-term bed-ridden patients, aspiration pneumonia, or viral pneumonia (Recommended Level ⅢA). If conventional tests fails to identify the pathogen and empirical treatment proves to be ineffective, or if special pathogen infection such as viruses, severe or complex infection, or immunosuppression is suspected, it is advised to use invasive procedures to obtain bronchoalveolar lavage fluid (BALF), pleural effusion, or lung biopsy, and to conduct molecular biology testing (PCR, mNGS, tNGS, etc.) concurrently with conventional pathogen tests (Recommended Level ⅢA).Recommendation 4:The pharmacokinetics (PK) changes of antimicrobial drugs in elderly patients and necessity of dosage reduction should be evaluated according to the unique physiological characteristics of the elderly, such as declining body function, the presence of multiple diseases, and potential medication interactions. It is recommended to combine the PK/PD characteristics of antimicrobial drugs and therapeutic drug monitoring (TDM) methods to guide the individualized and precise prescription for elderly patients with pneumonia. This approach aims to ensure efficacy, minimizing the risk of bacterial resistance, and reduce the incidence of adverse reactions (Recommended Level Ⅱ-2B).Recommendation 5:Timing of treatment: Empiric antimicrobial therapy should be initiated as soon as the diagnosis is made. Except for outpatient clinic visitors with mild symptoms, properly collected respiratory secretions and blood samples should be sent without delay for pathogenic microorganisms testing. During the influenza season, timely empiric antiviral therapy should be initiated without positive result (Recommended Level Ⅱ-1A).Recommendation 6:Coverage of possible pathogens: Due to the increased detection rate of various pathogens such as gram-negative bacteria, anaerobic bacteria, fungi, etc., the initial treatment should cover the possible pathogens. Individualized treatment should be started according to the estimation of drug resistance risk, the of PK/PD principle, and potential drug side effects (Recommended Level Ⅱ-1A).Recommendation 7:Appropriate treatments for promoting sputum drainage and airway clearance in elderly pneumonia patients should be chosen after a comprehensive evaluation of the patient's condition. It is crucial to assess the patient's coughing efficacy to avoid asphyxia (Recommended Level ⅢA).Recommendation 8:We recommend cautious use of glucocorticoids in elderly pneumonia patients. When it is indeed necessary to use glucocorticoids in severe pneumonia cases accompanied by septic shock and hemodynamic instability, it's crucial to tailor drug regimens carefully, monitor closely for adverse reactions, and avoid excessive or prolonged glucocorticoid use (Recommended Level ⅢB).Recommendation 9:Assessing the swallowing abilities of elderly patients is important, and individuals with dysphagia should undergo swallowing rehabilitation. These measures can help reduce the risk of aspiration pneumonia, such as adopting a semi-recumbent posture, thickened fluids and soft foods, proper dental care, tube feeding, and discontinuing medications that increase the risk of aspiration pneumonia in older patients (Recommended Level ⅡA).Recommendation 10:We recommend that elderly individuals get an annual influenza virus vaccine (Recommended Level ⅠA), 23-valent pneumococcal polysaccharide vaccine (PPV 23) or the 13-valent pneumococcal conjugate vaccine (PCV 13) to prevent CAP (Recommended Level ⅠB), and COVID-19 vaccine should also be recommended in accordance with national guidelines (Recommended Level ⅠA).Recommendation 11:Older individuals should quit smoking, limit alcohol intake, participate in moderate-intensity physical activity (Recommended Level Ⅱ-1A), have regular dental examinations, maintain good nutritional status and personal hygiene, and avoid close contact with children with acute viral respiratory infections (Recommended Level Ⅱ-2A).Recommendation 12:The super-elderly are more likely to experience geriatric syndromes, particularly sarcopenia and frailty, which are closely associated with the occurrence of aspiration pneumonia. Preventing and improving sarcopenia and weakness through nutrition supplement, exercise, cognitive training, etc., can effectively reduce the incidence of pneumonia (Recommended Level ⅢA).Recommendation 13:We recommend that older adults with chronic underlying medical conditions, who are at increased risk of developing pneumonia, should receive personalized management and comprehensive preventive measures to strengthen the management of underlying diseases. Perioperative care for older patients should be optimized to reduce the risk of postoperative pneumonia (Recommended Level ⅢA).

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.

This clinical case presents an unusual case of Lemierre's syndrome (LS) in a young woman of 38-year-old. She arrived in the Emergency Department with a high fever and pharyngology resistant to antibiotic therapy with clarithromycin, ceftriaxone, and cortisone for two weeks. At the blood sampling, there is a marked leucocytosis, and the advice of the otolaryngologist is required given the strong pain in the throat. Due to the tonsillar abscess, a neck CT with a contrast medium is necessary for the otolaryngologist's opinion. The CT shows thrombosis of the jugular vein and left subclavian, with thickening of soft perivascular tissues; these findings suggest Lemierre's syndrome: a septic thrombophlebitis of the jugular vein that occurs as a complication of a peritonsillar abscess. The diagnostic process is then completed with a chest HR-CT, which reveals lung density and excavation areas suggesting tuberculosis. Blood culture reveals the presence of Veillonella Parvula (an anaerobic gram-negative coccus), sputum culture reveals the presence of some colonies of Enterobacter cloacae complex, real-time PCR examination on sputum reveals the presence of Streptococcus Pneumoniae and the borderline presence of rhinovirus. Microbiologists, after these results and neck and chest CT with a contrast agent, agree with the diagnosis of suspected LS at an early stage: a septic dissemination fortunately limited only to the neck and lungs region.

Odontogenic infections can spread to the respiratory tract. Despite the known role of Tannerella forsythia as the primary pathogen in periodontitis, the association between T. forsythia infection and risk of pneumonia or lung abscess remains unknown. In this report, we present a case of lung abscess caused by T. forsythia infection. The pathogen was detected by metagenomic next-generation sequencing (mNGS) in the bronchoalveolar lavage fluid of the patient. The clinical characteristics and possible mechanisms of the infection are discussed. T. forsythia is a conditional pathogen that can cause lung abscess in the presence of helper bacteria and reduced host immune status. The course of treatment should be personalized and might be longer than 3 months.

A lung abscess is characterized as a clinical ailment arising from the localized suppurative necrosis of lung parenchyma. This condition primarily results from the complications of aspiration pneumonia due to anaerobic microorganisms originating from the oral cavity. Clinically, patients typically manifest symptoms such as fever, malaise, and a productive cough persisting over several weeks. The majority of lung abscess cases acquired within the community stem from anaerobic bacterial infections, often exhibiting a polymicrobial nature. We present a 51-year-old female with intrapulmonary abscess and empyema, with isolation of Veillonella species. She has a 25-pack-year smoking history. Two weeks prior to arrival at our facility, she experienced intermittent shortness of breath, fever, and subjective fever. Her primary care physician ordered an outpatient computed tomography (CT) which showed evidence of a large right-sided fluid collection. Initial chest X-ray at our facility revealed extensive opacification of the middle and right lower hemithorax, believed to be a large-sized pleural effusion with adjacent pneumonia or atelectasis. She was given a working diagnosis of right-sided empyema. Cardiothoracic surgery was consulted and video-assisted thoracoscopic surgery (VATS) was performed. A very large collection of grossly purulent material was evacuated and revealed a large intrapulmonary abscess. Over 400 cc of frank pus was collected and sent for microbiological analysis. Anaerobic culture demonstrated 3+ Peptostreptococcus species and 3+ Veillonella species. The genus Veillonella consists of a small, strictly anaerobic, gram-negative cocci that lacks flagella, spores, and capsules. This genus obtains energy from the utilization of short-chain organic acids that are present in the oral cavity and intestinal tract. Oral Veillonella is strongly associated with biofilms, causing human oral infectious diseases such as periodontitis and dental caries. Literature states that this organism has been isolated in a limited number of chronic pneumonitis cases. To date, the most common organism isolated from lung abscesses is Streptococcus in adult patients and Staphylococcus aureus in pediatric patients. We strive to elucidate the distinctive clinical presentation evident in this case, alongside a comprehensive understanding of the unusual pathogens identified in the disease's pathogenesis.

(1) Background: Lung abscess is a lung infection that leads to the destruction of the lung parenchyma, resulting in a cavity formation and central necrosis filled with purulent fluids. It is an uncommon pediatric problem, and there is a paucity of literature reviews on this subject, especially for the pediatric age group. Lung abscess is commonly divided into those considered primary in previously well children or secondary in those with predisposing co-morbidities. The predominant pathogens isolated from primary lung abscesses are the aerobic organisms, including streptococcal species, Staphylococcus aureus, and Klebsiella pneumoniae, while anaerobic bacteria such as Bacteroides species are predominant in secondary groups. Children usually present with fever, cough, shortness of breath, chest pain, and sputum. While physical examination may reveal diffuse crackles on auscultation, the diagnosis is usually confirmed by chest X-ray. (2) Methods: We report four different cases with lung abscesses from both primary and secondary group with similar presentations and radiological findings, but the approach was different in each according to the underlining cause. (3) Conclusions: Conservative therapies with a prolonged course of antibiotics remain the cornerstone of therapy for both primary and secondary lung abscesses. The underlying cause should be considered when there is a suboptimal response. However, invasive intervention is becoming more popular with better yield, shorter duration of antibiotics and admission, and excellent prognosis.