Background and objectives The Salmonella strains causing bloodstream infection show wide genetic diversity together with different antibiotic resistance profiles worldwide. The response of typhoidal Salmonella to standard antimicrobial treatments has become increasingly concerning during the past few decades. This study was conducted to evaluate the occurrence rate, antibiotic susceptibility patterns, and clinical characteristics of patients with Salmonella bacteraemia in a tertiary care hospital in Pune, Maharashtra, India. Methods A cross-sectional study was conducted from March 2024 to March 2025, analysing blood culture-confirmed cases of enteric fever. All patients with Salmonella-positive cultures were included, and data were gathered from clinical and microbiology records. Results Out of 6,862 blood cultures processed, 42 (0.6%) tested positive for Salmonella species. Of these, 50% were Salmonella Typhi, 36% were Salmonella Paratyphi A, and the remaining 14% included S. Cholerasuis, S. Typhimurium, and S. Gallinarum. All S. Typhi and S. Paratyphi A isolates were fully susceptible to first-line antibiotics, including chloramphenicol, amoxicillin, and co-trimoxazole, as well as to ceftriaxone and cefixime. However, 78.5% of isolates showed reduced susceptibility to ciprofloxacin. Initial disc diffusion testing suggested potential azithromycin resistance in 11 isolates, but confirmatory E-strip testing found none to be resistant based on MIC values. One S. Paratyphi A isolate exhibited a notably high MIC of 24 µg/mL, which is not classified as resistant according to U.S. NARMS guidelines. Interpretation and conclusions The increasing azithromycin MIC values among typhoidal Salmonella indicate potential resistance development, so additional research should assess azithromycin susceptibility patterns in detail.

Castellaniella defragrans is an environmental Gram-negative, non-fermenting β-proteobacterium that is not known as a human pathogen. Here, we report the first documented case of C. defragrans bacteraemia in an 82-year-old man with monoclonal B-cell lymphocytosis, subsequently diagnosed with chronic lymphocytic leukaemia, who presented with fever, confusion and clinical signs of sepsis. Blood cultures showed sustained growth of C. defragrans for 7 days. Imaging revealed pulmonary consolidations and mediastinal infiltration suggestive of mediastinitis. Further investigations did not identify a clear additional infectious focus. In addition, an immunological evaluation revealed severe cellular and humoral immunosuppression. Antimicrobial therapy with high-dose meropenem led to bacteraemia clearance and progressive clinical improvement. Treatment was completed with oral sulfamethoxazole-trimethoprim for a total of five weeks. This case highlights the potential of environmental microorganisms to cause severe infections in immunocompromised hosts.

Antimicrobial resistance (AMR) in Gram-negative pathogens poses a critical threat in intensive care units (ICUs). This retrospective observational study aimed to determine the prevalence and phenotypic resistance profiles of extended-spectrum β‑lactamase (ESBL)-producing and carbapenem‑resistant Klebsiella pneumoniae among ICU patients at a tertiary hospital in southwestern Saudi Arabia (2020-2021). Clinical specimens (n=179) from patients with hospital‑acquired infections were processed using standard culture, Vitek 2 identification, and phenotypic confirmatory tests (combination disc test for ESBLs and modified carbapenem inactivation method for carbapenemase). Of 543 total samples, 49 (9.0%) were identified as K. pneumoniae. ESBL production was detected in 15/49 (30.6%) and carbapenemase production in 6/49 (12.2%) of isolates. The highest resistance rates were observed against piperacillin‑tazobactam (55.1%), cefotaxime (55.1%), imipenem (53.0%), and meropenem (53.0%), while tigecycline (100% susceptibility) and amikacin (93.9% susceptibility) remained the most effective agents. Notably, susceptibility to trimethoprim‑sulfamethoxazole was 83.7% (corrected figure). Children under 10 years and adults aged 21-40 years showed the highest infection rates. The alarmingly high prevalence of ESBL and carbapenemase phenotypes, coupled with significant multidrug resistance, underscores the urgent need for routine molecular surveillance and targeted antibiotic stewardship in this region. Rapid phenotypic screening combined with genotypic confirmation is essential to guide empirical therapy and curb the spread of these high‑risk clones in critically ill populations.

Chronic bronchial infection by Stenotrophomonas maltophilia in non-cystic fibrosis (non-CF) bronchiectasis poses a major therapeutic challenge due to multidrug resistance and biofilm-forming capacity. We report a 19-year-old athlete with a one-year history of productive cough, dyspnea, and hemoptysis, whose CT scan revealed bibasilar cylindrical bronchiectasis. Following the failure of oral levofloxacin monotherapy and a subsequent sputum culture showing intermediate susceptibility to cotrimoxazole, a combination regimen was initiated. The patient received systemic trimethoprim-sulfamethoxazole combined with intermittent 28-day cycles of inhaled levofloxacin to leverage drug synergy and achieve high local concentrations capable of penetrating the bacterial biofilm. This dual approach achieved complete symptomatic remission, stable lung function, and microbiological clearance. To our knowledge, this is the first report documenting successful S. maltophilia eradication using inhaled levofloxacin in non-CF bronchiectasis, suggesting that this combination may be an alternative therapeutic strategy deserving further evaluation in future studies.

Patients suffering from Urinary Tract Infections (UTIs) are faced with multidrug resistance and a lack of treatment options. An alternative strategy to traditional bactericidal drug design is to disarm pathogenic bacteria by targeting the regulation of virulence factors. Small-molecule CpxRA phosphatase inhibitor compound 26, hereafter referred to as Cpx26, has shown efficacy in a murine UTI model; however, the impact of pharmacological modulation of CpxRA on bacterial physiology is undefined. Herein, we report the activity of Cpx26 in phenotypic assays to provide insight into its mechanism of action and antivirulence properties. Cpx26 significantly inhibited swimming motility, biofilm formation, and adhesion to bladder epithelial cells at concentrations >60-fold below its MIC. Combination with first-line UTI antibiotics was explored, and synergy was observed with trimethoprim/sulfamethoxazole and fosfomycin, implying potential clinical benefit. This work highlights the potential of antivirulence therapies for prevalent infections such as UTIs.

Elizabethkingia meningoseptica is a gram-negative bacillus. Increasing body of literature shows that opportunistic infections may be caused by this Gram negative bacillus in immunocompromised adults and neonates. We describe a case of a preterm neonate born at 33 weeks of gestation who presented with fever and reluctance to feed for two days at one month after birth. Initial laboratory tests of blood and cerebrospinal fluid cultures showed evidence of late-onset sepsis and meningitis caused by E. meningoseptica, which was sensitive to piperacillin/tazobactam, cefoperazone/sulbactam, trimethoprim/sulfamethoxazole, levofloxacin, and minocycline. The neonate underwent sequential anti-infective therapy regimens consisting of: 1) cefoperazone/sulbactam (2:1) in combination with levofloxacin; 2) cefoperazone/sulbactam (2:1) paired with rifampicin; and 3) linezolid administered concomitantly with rifampicin. The neonate exhibited clinical manifestations of ventricular dilatation accompanied by hydrocephalus. The neonate received an 85-day course of anti-infective treatment during hospitalization. Follow-up cranial computed tomography (CT) imaging performed four months post-discharge demonstrated complete resolution of the previously observed complications.

Stenotrophomonas maltophilia is a globally distributed, aerobic, non-fermenting Gram-negative bacillus increasingly recognized as an opportunistic pathogen in hospitalized and immunocompromised patients. Clinical interpretation is challenging because respiratory and device-associated isolates may represent colonization, polymicrobial infection, or true invasive disease. Recent genomic studies further suggest that organisms historically identified as S. maltophilia comprise a genetically diverse species complex, with implications for epidemiology, virulence, resistance surveillance, and susceptibility testing. Treatment is difficult because of biofilm formation, persistence in water-associated healthcare reservoirs, and intrinsic or acquired resistance mediated by L1 and L2 β-lactamases, multidrug efflux pumps, reduced permeability, mobile resistance determinants, and biofilm-associated tolerance. Current IDSA guidance identifies cefiderocol monotherapy as the preferred treatment for invasive S. maltophilia infection, whereas aztreonam-avibactam and agents such as trimethoprim-sulfamethoxazole, levofloxacin, and minocycline occupy alternative or combination-based roles. Nevertheless, the therapeutic evidence base remains uneven, and clinical decisions should integrate infection severity, source control, susceptibility findings, pharmacokinetic/pharmacodynamic (PK/PD) exposure, toxicity, infection site, and host-related factors. This review summarizes advances in taxonomy, epidemiology, pathogenesis, diagnostics, resistance, treatment, infection prevention, and genomic surveillance, and highlights the need for standardized identification, validated breakpoints, prospective comparative-effectiveness studies, and pragmatic or adaptive trial designs.

In the present case report, a cutaneous infection caused by the rare actinomycete Nocardiopsis sp. TSRI0078 is described. A 77-year-old woman with a medical history of hypertension and diabetes presented with ulcerated purplish-red nodules on the lower extremities that had persisted for 3 months. A histopathological examination revealed infectious granulomas predominantly composed of neutrophils. After empirical antibiotic therapy proved ineffective, the pathogen was confirmed to be Nocardiopsis sp. TSRI0078 via polymerase chain reaction testing, gene sequencing, and microbial culture. Subsequent treatment with oral trimethoprim-sulfamethoxazole led to gradual regression of the lesions and scar formation. With only 11 human infection cases reported globally, a clear understanding of the clinical manifestations of Nocardiopsis infections is lacking. This pathogen should be considered in the differential diagnosis of chronic, unexplained cutaneous lesions, particularly in patients with underlying diseases. A combination of molecular and conventional microbiological examinations facilitates early diagnosis, and trimethoprim-sulfamethoxazole may represent an effective therapeutic option.

BACKGROUND Severe Pneumocystis jirovecii pneumonia (PJP) in renal transplant recipients (RTRs) can rapidly progress to acute respiratory distress syndrome (ARDS) and is associated with high mortality. Glucocorticoids (GCs) play a paradoxical role, constituting a risk factor for infection and a trigger for immune reconstitution inflammatory syndrome upon withdrawal; they may also serve as a therapeutic agent for lung injury. We evaluated the efficacy of a standardized triple-therapy regimen designed to address this paradox. CASE REPORT We analyzed 7 RTRs admitted to the intensive care unit (ICU) with severe PJP-ARDS between June 2023 and September 2024. The cohort had a median age of 49 years; all patients had prior chronic low-dose GC maintenance therapy without PJP prophylaxis. All diagnoses were confirmed by metagenomic next-generation sequencing. After the onset of severe PJP-ARDS, all immunosuppressive agents were discontinued; patients were treated with trimethoprim-sulfamethoxazole and caspofungin. Early adjunctive intravenous methylprednisolone was administered to all patients, including 4 who received treatment upon ICU admission. The median starting dose was 80 mg/day (range, 40-120 mg/day), with a median treatment duration of 11 days (range, 5-17 days) and median cumulative dose of 580 mg (range, 200-840 mg). Following this triple-therapy regimen, the median duration of mechanical ventilation was 14 days, and the survival rate was 100% (7/7); no severe secondary infections or uncontrolled hyperglycemia occurred. CONCLUSIONS Despite constituting a predisposing factor for PJP, early adjunctive GC administration-combined with robust anti-Pneumocystis therapy-may be a safe and promising strategy for managing severe PJP-ARDS in RTRs.