搜索结果：Pneumonia

The dynamics of multidrug-resistant pathogens in response to large-scale societal and environmental disruptions remain poorly understood. Here, we investigated 528 Klebsiella pneumoniae clinical isolates collected from a tertiary hospital in Qingdao, China, spanning 2016 to 2023, with a primary focus on 2018-2023, across pre-, during-, and post-COVID-19 pandemic periods. All isolates underwent whole-genome sequencing. We identified SL258 and SL23 as dominant sequence lineages, with prevalent serotypes including K1 and O1. A wide range of resistance and virulence determinants were detected, particularly ybt genes, which showed strong lineage-specific associations. The COVID-19 pandemic coincided with a transient expansion of SL258 and an overall increase in antimicrobial resistance levels, followed by post-pandemic diversification of resistant clones. The structural complexity of the K. pneumoniae population decreased during the pandemic but rose significantly afterward, with the emergence and expansion of multiple previously rare multidrug-resistant (MDR) lineages. A serotype shift within SL258, from K25/O5 to K64/O2a, was also observed. These findings highlight the selective pressures exerted by hospital-based infection control strategies and antimicrobial usage patterns during the pandemic, which may have shaped the persistence and replacement of dominant MDR clones. Our study underscores the importance of genomic surveillance in tracking resistance evolution and pathogen adaptation in clinical environments under crisis conditions.IMPORTANCEMultidrug-resistant Klebsiella pneumoniae (MDR-KP) is a critical global threat, linked to longer hospital stays, higher treatment costs, and worse patient outcomes. The COVID-19 pandemic placed unprecedented pressure on healthcare systems, altering antibiotic use and infection control practices that may have reshaped MDR-KP populations. Our 8-year surveillance of clinical K. pneumoniae strains in Qingdao reveals how pandemic-related disruptions drove shifts in lineage dominance, antimicrobial resistance profiles, and serotype distribution. These findings highlight the vulnerability of clinical microbial ecosystems to large-scale public health crises and underscore the need for sustained genomic surveillance. By establishing a longitudinal institutional baseline for MDR-KP dynamics, our work provides actionable insights to guide local infection control and antimicrobial stewardship, helping to mitigate the spread of resistant pathogens in similar clinical settings during future health emergencies.

Klebsiella pneumoniae, a major nosocomial pathogen, is increasingly associated with multidrug resistance and carbapenem production, posing a significant therapeutic challenge on a global scale. The study aimed to determine the distribution, antimicrobial susceptibility pattern, and molecular identification of blaKPC-2 and blaVIM genes among carbapenem-resistant K. pneumoniae isolated from clinical specimens. Between January and June 2024, a hospital-based cross-sectional study was carried out at Kirtipur Hospital in Nepal. Standard microbiological protocols were adopted for the processing of 5002 clinical samples. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method following CLSI guidelines. The modified carbapenem inactivation method (mCIM) and the EDTA-modified carbapenem inactivation method (eCIM) were used to confirm carbapenemase production phenotypically, and the polymerase chain reaction (PCR) was used to detect the blaKPC-2 and blaVIM genes at the molecular level. Of the total samples, 18.3% (917) showed bacterial growth, with K. pneumoniae accounting for 7.6% (n = 70) of isolates, predominantly from wound/pus (35.7%), urine (32.8%), and blood (17.1%) specimens. High resistance was observed against imipenem (68.6%), ceftazidime (64.3%), and ceftriaxone (62.9%), whereas tigecycline and doxycycline remained the most effective ones. Twelve (30.8%) of the 39 carbapenem-resistant isolates were determined to be carbapenemases producers, all harboring blaKPC-2 (100%) and three (25%) additionally carrying blaVIM. The dominance of KPC-mediated resistance among the hospitalized patients, underscores the need for rigorous infection control, ongoing molecular surveillance, and prudent antimicrobial stewardship to stop the spread of high-risk K. pneumoniae strains in healthcare environments.

Influenza and pneumonia associated sepsis contribute markedly to mortality among the older adults in the United States. Yet, the long-term mortality trajectories and demographic and geographic heterogeneity have not been well characterized. We used the CDC WONDER database to identify deaths involving influenza- and pneumonia-associated sepsis among U.S. adults aged &#x2265;65 years from 1999 to 2022 and applied Joinpoint regression to assess temporal changes in mortality trends. From 1999 to 2022, a total of 730,918 deaths involving influenza and pneumonia associated sepsis were identified among older adults in the United States. Overall mortality exhibited an initially stable pattern followed by a sustained increase, peaking during the COVID-19 pandemic, and subsequently declining slightly but remaining at a relatively high level. Among older adults, the age-adjusted mortality rate (AAMR) rose from 68.96 in 1999 to 81.89 in 2022, with the steepest increase during 2011-2022 (APC=3.63, 95% CI 2.20-5.07; p<0.01). Over the entire study period, higher mortality rates were persistently observed among males, individuals aged&#x2265;85 years, residents of the Southern United States, Black or African American individuals, and those living in non-metropolitan areas. A steadily increasing mortality burden related to influenza and pneumonia associated sepsis has been observed among U.S. older adults in recent years, with substantial disparities across population subgroups and geographic regions.

To analyze the risk factors for carbapenem-resistant Klebsiella pneumoniae bloodstream infection (CRKP-BSI) in children. A total of 235 pediatric patients with Klebsiella pneumoniae bloodstream infection (KPN-BSI) admitted to our hospital from January 2015 to December 2025 were collected. According to the CLSI criteria, infections in which carbapenem- resistant Klebsiella pneumoniae was isolated from blood culture were defined as CRKP-BSI (n=110), and those in which carbapenem-susceptible Klebsiella pneumoniae was isolated were defined as CSKP-BSI (n=125). We compared clinical profiles of the two groups with the Mann-Whitney U test and chi-square test, and binary logistic regression was used to identify independent risk factors for CRKP-BSI. Children with CRKP-BSI were mainly distributed in the Premature Infant Department (49 cases, 44.60 %) and intensive care unit (36 cases, 32.70 %). Analysis of clinical characteristics showed that patient age, underlying diseases, antibiotic use duration &#x2265; 14 days, mechanical ventilation, surgical procedures during hospitalization, and hospital stay > 5 days were significantly associated with CRKP-BSI (all P < 0.05). Binary logistic regression multivariate analysis demonstrated that the mechanical ventilation (&#x3b2; = 2.896, OR = 18.106), surgical procedures during hospitalization (&#x3b2; = 1.116, OR = 3.052), and hospital stay > 5 days (&#x3b2; = 0.957, OR = 2.603) were independently associated with CRKP-BSI. It is concluded that mechanical ventilation, surgical interventions and prolonged hospitalization independently contribute to the development of CRKP-BSI in children. Enhanced monitoring and precise infection control strategies are required for vulnerable children to prevent CRKP-BSI.

Mycoplasma pneumoniae is one of the causative agents of community-acquired infections, with epidemic cycles recorded over 37 years and a current international revival after the COVID-19 pandemic. This study elaborates and critically examines a deterministic thirteen-compartmental mathematical model to understand the dynamics of Mycoplasma pneumoniae, including vulnerability stratification, dual-strain progression, and intervention pathways in healthcare. The positivity and boundedness of solutions are proved to establish the well-posedness of the model biologically. Local asymptotic stability of the disease-free equilibrium (DFE) is established when [Formula: see text] and global asymptotic stability at the endemic equilibrium when [Formula: see text] via Lyapunov functions. The model exhibits backward bifurcation as temporary immunity decays (when [Formula: see text]), suggesting that [Formula: see text], though necessary, is not sufficient for eradication of Mycoplasma pneumoniae. Optimal control with time-varying vaccination [Formula: see text], intensified treatment [Formula: see text], and prevention compliance [Formula: see text] reduces infectious and hospitalised compartments by 90-[Formula: see text], while the absence of controls allows endemic persistence. The results provide an evidence-based framework for designing targeted, cost-efficient interventions to control Mycoplasma pneumoniae epidemics and safeguard vulnerable populations.

To characterize reported cefiderocol (FDC)-resistant Klebsiella pneumoniae through a systematic review and reanalysis of available whole-genome sequencing (WGS) data. PubMed, Embase, and Web of Science were searched for original reports of FDC-resistant K. pneumoniae. Epidemiological, susceptibility, molecular, and available WGS data were extracted and reanalyzed. Iron-related disruptive events were compared between high- and lower-MIC groups among eligible non-outbreak isolates. Seventy-six studies reported 785 FDC-resistant K. pneumoniae isolates from 24 countries or regions. Forty-four studies provided WGS data, yielding 145 non-duplicate genomes. The WGS subset comprised 31 sequence types (STs), most commonly ST147, ST16, ST512, and ST307. Carbapenemase genes were detected in 143 genomes, most frequently blaNDM (71/145, 49.0%), blaKPC (65/145, 44.8%), and blaOXA-48-like (31/145, 21.4%); 31 genomes (21.4%) carried carbapenemase genes from two groups. Iron uptake- or regulation-related disruptive events were identified in 59 isolates (40.7%). Among 71 non-outbreak isolates with MIC data, these events were more frequent in the high-MIC group than in the lower-MIC group (78.3% vs 22.9%; OR&#x202f;=&#x202f;12.1, 95% CI 3.82-36.18; P < 0.0001), and disruption involving two or more iron-related genes was observed only in the high-MIC group. Among isolates with available data, resistance to ceftazidime-avibactam (105/129, 81.4%) and ceftolozane-tazobactam (75/75, 100%) was frequent, whereas aztreonam-avibactam resistance was detected in 4 of 60 isolates (6.7%). Available WGS data indicate that reported FDC-resistant K. pneumoniae isolates are genetically diverse, commonly carry complex &#x3b2;-lactamase backgrounds, and harbor candidate iron-related genomic alterations associated with higher FDC MICs.

Tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta (YWHAZ, 14-3-3&#x3b6;), a key regulator of intracellular signaling and inflammatory responses, has not been investigated in Streptococcus pneumoniae (S.pn) infection. We first employed Western blotting to detect the expression and activation of YWHAZ in murine RAW264.7 macrophages and a mouse model of S.pn pneumonia. A small-molecule inhibitor BV02 was used to pharmacologically block YWHAZ function both in vitro and in vivo. Subsequent evaluations included the production of inflammatory cytokines via ELISA, the detection of autophagy-related biomarkers, bacterial clearance capacity by colony-forming units (CFU) enumeration, and lung pathological injury using HE staining. Furthermore, Western blot was applied to determine the activation of TLR4 and its downstream core signaling pathways, to further elucidate the underlying molecular mechanisms. S.pn infection induced YWHAZ phosphorylation, which further mediated the activation of the NF-&#x3ba;B and p38MAPK inflammatory signaling pathways. Pharmacological inhibition of YWHAZ with BV02 downregulated NLRP3 and IL-1&#x3b2; expression, and reduced the secretion of key pro-inflammatory cytokines including TNF-&#x3b1;, IL-6, IL-1&#x3b2;, and IL-18. Moreover, BV02 modulated autophagic activity upon S.pn infection and enhanced host bacterial clearance ability. Mechanistically, YWHAZ functions as a pivotal molecular bridge linking TLR4 to downstream pro-inflammatory signaling cascades during host response against S.pn infection. During S.pn infection, YWHAZ undergoes phosphorylation and functions as a downstream effector of TLR4 signaling. It exacerbates macrophage-mediated inflammatory responses, impairs autophagy-associated bacterial clearance, and aggravates pulmonary immunopathology, highlighting YWHAZ as a promising therapeutic target for pneumococcal pneumonia.

Pneumonia (PNA) is a leading cause of hospitalization among older adults, yet its effect on complications following total joint arthroplasty (TJA) remains unknown. This study evaluated the association between PNA within two years prior to total hip arthroplasty (THA) or total knee arthroplasty (TKA) and periprosthetic joint infection (PJI) and other complications. Patients undergoing primary THA or TKA were identified from a national administrative claims database. Patients who had prior PNA were matched to controls who did not have PNA based on demographics and baseline comorbidities. Outcomes included postoperative medical and surgical complications, including PJI. Subgroup analyses were performed by PNA etiology and timing relative to surgery. In the THA cohort, 14,607 patients who had prior PNA were matched to 14,607 controls. Overall PNA was not associated with increased PJI risk; however, prior Staphylococcal PNA was (odds ratio (OR) 2.4, 95% confidence interval (CI) 1.2 to 5.0), particularly when occurring within three months of surgery (OR 5.2, 95% CI 1.8 to 14.5). In the TKA cohort, 6,271 matched pairs were analyzed. Overall PNA was not associated with increased PJI risk (P = 0.218), while bacterial PNA was (OR 1.98, P = 0.002); viral PNA was not (P = 0.842). Klebsiella pneumoniae carried the highest PJI risk (OR 12.22, P < 0.001). Bacterial PNA occurring three to six months (OR 2.78, P = 0.022) and six to 12 months prior to TKA (OR 2.98, P = 0.001) was also associated with increased PJI odds. Pathogen-specific PNA demonstrated time-dependent associations with PJI following TJA. Staphylococcal PNA within three months of THA and bacterial PNA, particularly Klebsiella pneumoniae, occurring three to 12 months before TKA were associated with elevated PJI risk. These findings suggest that PNA etiology and timing may be relevant in preoperative risk assessment for TJA.

To describe in detail changes in the incidence of invasive pneumococcal disease in the Czech Republic during and after the COVID-19 pandemic. Another objective is molecular analysis of S. pneumoniae isolates of serotypes 3 and 19A recovered in the Czech Republic between 2018 and 2024. Data on the incidence of invasive pneumococcal disease and S. pneumoniae serotypes were obtained from the invasive pneumococcal disease surveillance program in the Czech Republic. S. pneumoniae isolates of serotypes 3 (63) and 19A (66) from 2018-2024 were subjected to whole genome sequencing (WGS) to characterize the GPSCs (Global Pneumococcal Sequence Clusters) and STs (sequence types) and place them in a&#xa0;global context. During the COVID-19 pandemic, a&#xa0;significant decline was observed in the incidence of influenza in the Czech Republic. Following the pandemic, the incidence of influenza rose again to significantly higher levels than before the pandemic. Compared to the 2018-2019 period, the incidence of certain serotypes increased in 2023-2024, including vaccine serotypes 3, 4, 14, and 15B, while the incidence of serotypes 8, 12F, and 15A, among others, decreased. Whole genome sequencing analysis demonstrated the dominance of GPSC12 ST-180 among serotype 3 isolates throughout the study period. Among serotype 19A isolates, GPSC4 prevailed, particularly ST-416. The COVID-19 pandemic has demonstrated how rapidly the epidemiological situation of invasive pneumococcal disease can change and that continuous, systematic surveillance of invasive pneumococcal disease is necessary. The best prevention against IPD is vaccination, primarily with higher valency pneumococcal conjugate vaccines.

Viral pneumonia, caused by highly transmissible respiratory pathogens including influenza viruses, respiratory syncytial viruses, and coronaviruses, remains a major global health challenge due to its rapid disease progression and high morbidity and mortality. Despite significant advances in antiviral therapies, vaccination strategies, and diagnostic technologies, current clinical interventions are still constrained by low bioavailability, insufficient pulmonary targeting, systemic toxicity, inadequate immunomodulation, and suboptimal early detection. Nanotechnology, as a multidisciplinary approach integrating materials science, immunology, and drug delivery engineering, has been proposed to overcome these limitations. However, comprehensive reviews addressing the fabrication strategies, and therapeutic applications of nanomaterials in viral pneumonia remain limited. This review provides an overview of nanoparticle-based systems, emphasizing rational design principles for pulmonary-targeted therapy and summarizing recent advances in prevention, diagnosis, and treatment. By integrating materials design, biological mechanisms, and translational challenges, it offers a comprehensive framework for interdisciplinary nanotechnology application in viral pneumonia, with strategic directions for lung-targeted delivery, immune modulation, and early diagnosis.

Multidrug-resistant (MDR) Klebsiella pneumoniae, particularly high-risk clones such as sequence type (ST) 147, have been increasingly reported worldwide. However, data on their occurrence in reproductive disorders of companion animals remain limited. This study describes, for the first time, an extended-spectrum &#x3b2;-lactamase (ESBL)-producing K. pneumoniae ST147 isolated from a canine paraprostatic abscess. The isolate (UNISA-DOG-2025) was characterized by antimicrobial susceptibility testing and whole-genome sequencing. Phenotypic analysis revealed an MDR profile, supported by the detection of multiple resistance genes, including &#x3b2;-lactamases (blaCTX-M-8, blaCTX-M-15, blaOXA-1, blaOXA-9), as well as determinants conferring resistance to aminoglycosides, quinolones, sulfonamides, tetracyclines, and trimethoprim. Several of these genes were located on an in silico predicted conjugative IncM1 plasmid, suggesting potential for horizontal dissemination. Phylogenomic analysis demonstrated close relatedness to globally distributed ST147 strains, predominantly associated with human infections. To our knowledge, this is the first report of K. pneumoniae ST147 causing a canine paraprostatic abscess. These findings highlight the clinical relevance of MDR Enterobacterales in canine reproductive disorders and reinforce the need for antimicrobial stewardship and genomic surveillance in veterinary medicine.

Bacteria of the genus Klebsiella, particularly members of the Klebsiella pneumoniae and Klebsiella oxytoca species complexes, are common commensals of the intestinal microbiota in neonates and infants. Under certain conditions, they may exhibit pathogenic behaviour and cause severe nosocomial infections, especially in preterm and immunocompromised children. Colonization by Klebsiella spp. is influenced by a&#xa0;range of perinatal and postnatal factors. The clinical significance of these opportunistically pathogenic strains is further amplified by their ability to acquire multidrug resistance, which complicates the treatment of infections and increases the risk of adverse clinical outcomes. This review focuses on the analysis of conditions and factors involved in the occurrence of Klebsiella species in the developing neonatal and infant gut microbiota and their role in nosocomial infections. Particular attention is given to species within the K.&#xa0;pneumoniae and K. oxytoca complexes, which include the most clinically relevant opportunistically pathogenic strains of this genus in this age group. In addition, this review discusses the potential of experimental animal models in studying the pathogenesis of these infections.

Nasopharyngeal carriage of Streptococcus pneumoniae is a key factor for transmission, invasive disease, and antimicrobial resistance. Data on pneumococcal carriage in children in Cypriot are limited. We conducted a cross sectional study from December 2023 to May 2024, during a period of high PCV10 and PCV13 vaccine coverage in Cyprus, including children aged six months to six years who attended outpatient clinics in Cyprus. Nasopharyngeal swabs were cultured, and Streptococcus pneumoniae isolates were identified using conventional methods and confirmed by polymerase chain reaction. Serotyping was performed using multiplex polymerase chain reaction, latex agglutination, and whole-genome sequencing when needed. Antimicrobial susceptibility was assessed according to European guidelines. Logistic regression was used to identify risk factors for carriage. A total of 809 children were included, 83.85% of whom were fully vaccinated with pneumococcal conjugate vaccines. The overall prevalence of carriage was 35.72%. Recent antibiotic use (OR 1.47, 95% CI 1.03-2.12) and daycare attendance (OR 1.89, 95% CI 1.37-2.63) were associated with increased carriage, whereas receipt of at least one vaccine dose was protective (OR 0.38, 95% CI 0.17-0.82). Among the 290 isolates, 34 distinct serotypes were identified, predominantly non-vaccine types including 15B, 23A, 23B, 24, 6C, and 15A. Most isolates (68%) were not covered by available vaccines. Resistance was highest for erythromycin (54.32%), tetracycline (37.28%), and clindamycin (31.65%). Multidrug resistance occurred in 28.94% of the isolates, mainly in serotypes 24, 15A, and 19A. Despite extensive vaccination, pneumococcal carriage in Cypriot children remains high, with predominance of non-vaccine serotypes and substantial antimicrobial resistance. Continuous surveillance is essential to guide vaccination and antimicrobial stewardship.

Ventilator-associated pneumonia (VAP) is a major intensive care unit (ICU) complication, particularly in North Africa where multidrug-resistant (MDR) organisms are frequent. This study aimed to determine risk factors, microbiological patterns, and outcomes of VAP in a Tunisian tertiary ICU during the COVID-19 pandemic. We conducted a retrospective observational study including 422 mechanically ventilated patients. VAP was defined using modified Johanson criteria. A multivariable logistic regression model was performed to identify independent risk factors for VAP development, in accordance with STROBE guidelines. Time-related outcomes were not included in the model to avoid temporal bias. The VAP incidence was 24.2% (6.2 per 1,000 ventilator-days), with a median onset of 8 days after intubation. Independent risk factors for VAP included polytrauma, intrahospital transport, diabetes, male sex, and age > 75 years. COVID-19 ARDS was associated with a lower adjusted risk of VAP, likely reflecting selection and competing risk biases during the pandemic. Microbiological analysis showed a strong predominance of Gram-negative bacilli. Overall, 59% of isolates were MDR, mainly Acinetobacter baumannii and Klebsiella pneumoniae. Prior antibiotic exposure was strongly associated with MDR infections. ICU mortality among VAP patients was 40%, and hospital mortality reached 44%. In this pandemic-era single-center ICU cohort, VAP was associated with high morbidity and mortality and a substantial burden of MDR Gram-negative pathogens. These results highlight the impact of ICU-specific risk factors and prior antibiotic exposure, and should be interpreted within the context of a COVID-19-dominated ICU, limiting generalizability to non-pandemic settings.

The increasing prevalence of multidrug-resistant (MDR) Klebsiella pneumoniae necessitates alternative therapeutic strategies. Here, we isolated and characterized a lytic phage, vB_KpnS_SXK7, from hospital sewage and investigated the host's resistance mechanism. Morphological analysis identified it as a siphovirus-type phage. It exhibited a 30-min latent period, a burst size of 270 PFU/infected cell, and stability across pH 5-12 and temperatures up to 60&#xa0;&#xb0;C. Host range testing against 25 K. pneumoniae strains showed that vB_KpnS_SXK7 lysed 9 strains (36%). Whole-genome sequencing revealed a 49.1-kb circular dsDNA genome lacking tRNA, virulence, or antibiotic-resistance genes, confirming its safety profile. In vitro, vB_KpnS_SXK7 reduced bacterial viability within 2&#xa0;h. In a Galleria mellonella infection model, a single dose (MOI 100) rescued 80% of larvae from lethal challenge without toxicity. Genomic analysis of resistant mutant SXK7-R11 identified a single-nucleotide deletion in wzm, which encodes an ABC transporter permease essential for O-antigen assembly. This mutation impaired phage adsorption, which was restored by genetic complementation. These findings establish vB_KpnS_SXK7 as a promising preclinical candidate but highlight its vulnerability to resistance mechanisms involving O&#x2011;antigen&#x2011;associated pathways, supporting the development of phage cocktails targeting multiple receptors against MDR infections.

With notification rates for Legionnaires' disease (LD) rising in Europe and the United States, accurate case detection becomes increasingly important for individual patient management and public health surveillance. A six-predictor score has been proposed to identify community-acquired pneumonia (CAP) patients at increased risk of LD. We externally validated and updated this score to improve its practical usability. We analysed data from 196 patients with LD across 20 Swiss hospitals and 196 matched Legionella test-negative CAP controls (August 2022-March 2024). We evaluated the availability of the six original score predictors (fever, no/dry cough, hyponatremia, elevated CRP, elevated LDH, low platelet count) in routine care and assessed the score's discriminative performance. The dataset was split into development and validation cohorts to assess if model simplicity and predictive performance could be improved. The original score yielded 91% sensitivity (95% CI: 86-96%) and 35% (95% CI: 28-42%) specificity at a cut-off &#x2265;2. LDH was infrequently measured, and platelet count was a poor predictor. The simplified SwissLEGIO score (fever >38&#xb0;C, sodium <133 mmol/L, CRP >180 mg/L, no/dry cough, prior &#x3b2;-lactam therapy) showed high sensitivity (88-92%) and improved specificity (46-58%) at a cut-off &#x2265;2. The SwissLEGIO score is an easy-to-apply screening tool to rule out LD in hospitalised CAP patients. A scores <2 could reduce Legionella-specific testing by 36-52% (at a disease prevalence of 4%) while maintaining high sensitivity for case detection.

China's Healthcare Security Diagnosis-Related Groups (CHS-DRG) framework anchors inpatient payment to a relative weight (RW) set by each hospitalization's severity stratum. That stratum depends on the complications and comorbidities (CC) and major complications and comorbidities (MCC) identified among recorded secondary diagnoses, so ICD-10 documentation carries direct payment consequences. Evidence on diagnostic coding combination patterns in clinically complex populations, and on the methodological hazards of analyzing an exposure defined by grouper logic, remains limited. This single-center retrospective study used medical record front page and CHS-DRG grouping data (locally implemented national grouper, v2.0) for pneumonia hospitalizations discharged from Anhui Chest Hospital in 2025. The hospitalization was the unit of analysis; 131 met pre-specified criteria and were classified by recorded ICD-10 secondary diagnoses into three mutually exclusive coding patterns (basic-disease-only; basic disease with CC; enhanced complication). Because the exposure shares the grouper's own logic, its correspondence with the severity stratum is treated as definitional and the regressions as exploratory. Reporting follows STROBE and RECORD. Among 131 hospitalizations (mean age 70.4&#x2009;&#xb1;&#x2009;10.7 years; 91 of 131 male, 69.5%), 15 (11.45%), 20 (15.27%), and 96 (73.28%) fell into the basic-disease-only, basic disease with CC, and enhanced complication patterns. By construction each pattern mapped one-to-one onto its severity stratum. Total hospitalization expenditure, the only non-definitional outcome, rose across patterns (H&#x2009;=&#x2009;43.57, P&#x2009;<&#x2009;0.001): medians 5,938.62, 6,769.91, and 25,501.36 yuan (approximately US$827, US$943, and US$3,552); RW followed a parallel gradient (H&#x2009;=&#x2009;42.96, P&#x2009;<&#x2009;0.001). In exploratory regression, length of stay and the count of recorded chronic conditions co-varied with MCC entry (adjusted OR 1.234, 95% CI 1.101 to 1.384, and 1.411, 95% CI 1.144 to 1.741, respectively), both contemporaneous and partially coding-dependent rather than independent predictors. The structure of recorded ICD-10 diagnoses corresponded to CHS-DRG severity stratification and RW by definition rather than through an independent association, while realized expenditure rose in parallel. The study is best read as a cautionary illustration of definitional circularity: rule-conformant ICD-10 coding remains necessary for accurate stratification and equitable payment, but coding-pattern data alone cannot establish independent clinical or economic effects. Not applicable.

Organising pneumonia (OP) is a lung inflammation-repair pattern characterised by rapid and complete resolution. In rare instances, it may progress to respiratory failure with poor outcomes due to steroid unresponsiveness and limited treatment options. A man in his 70s presented with shortness of breath, without accompanying symptoms, signs or laboratory markers of infection. Broad-spectrum antibiotics and corticosteroids were administered. An extensive infectious and immunological workup yielded negative results. Despite these interventions, the patient's oxygen requirements increased, necessitating invasive mechanical ventilation. OP was confirmed on biopsy. The patient's respiratory status did not improve and he was unable to be weaned from mechanical ventilation, ultimately resulting in death. This case prompted a review of the literature on rapidly progressive OP, a rare subset of steroid-refractory cases and treatments trialled by other authors. Alternative immunosuppressive treatments include mycophenolate, cyclosporine, rituximab and intravenous immunoglobulin but their use is limited to case reports and series.