Anil Kumar

Carbapenem-resistant Enterobacterales (CRE) are an increasing public health concern, particularly as carbapenemase-producing isolates, such as NDM and OXA-48-like producers, become more prevalent. Rapid and accurate identification of carbapenemases is crucial to guide appropriate antibiotic therapy. Although recent epidemiologic data show that CRE increasingly harbor multiple carbapenemases, the performance of common phenotypic tests—the modified carbapenem inactivation method (mCIM) and EDTA-modified CIM (eCIM)—has not been well defined in these isolates. We examined the performance of mCIM and eCIM among CRE-encoding NDM, OXA-48-like, or both. We included 172 genotypically confirmed carbapenemase-encoding CRE isolates from perirectal swabs collected from patients admitted to two intensive care units at a hospital in South India. Isolates included Escherichia coli (53.5%), Klebsiella pneumoniae (41.3%), and Enterobacter species (5.3%). Overall, 112 isolates (65.1%) encoded NDM alone, 23 (13.4%) encoded OXA-48-like alone, and 37 (21.5%) encoded both NDM and OXA-48-like. mCIM positivity was 98.2% for NDM, 47.8% for OXA-48-like, and 94.6% for NDM+OXA-48-like encoders; among mCIM-positive isolates, eCIM positivity rates were 99.1%, 91%, and 97.1%, respectively. When compared to molecular carbapenemase gene detection, mCIM/eCIM was highly sensitive for classifying isolates encoding NDM as metallo-β-lactamase (MBL) producers, but significantly misclassified isolates encoding OXA-48-like as having an MBL or lacking a carbapenemase. In the largest collection of NDM and OXA-48-like co-encoding CRE isolates to date, mCIM/eCIM typically reported these as MBL producers. IMPORTANCE: Carbapenemase-encoding Enterobacterales infections are associated with substantial adverse health outcomes, making rapid and accurate carbapenemase detection essential for guiding antibiotic therapy. Although Enterobacterales carrying multiple carbapenemases are increasingly reported worldwide, the performance of common phenotypic assays, mCIM and eCIM, remains insufficiently defined for these strains. In this study of 172 genotypically confirmed carbapenemase-encoding Enterobacterales isolates from hospitalized patients in South India, mCIM/eCIM consistently classified NDM-encoding isolates as metallo-β-lactamase encoders. Additionally, mCIM/eCIM frequently misclassified OXA-48-like-encoding isolates as either metallo-β-lactamase encoders or carbapenemase-negative, highlighting the need to better understand the mechanisms underlying this variable activity. In the largest collection of NDM and OXA co-encoding Enterobacterales isolates reported to date, mCIM/eCIM generally reported co-encoding isolates as metallo-β-lactamase producers. Our results suggest that mCIM/eCIM performance may vary geographically due to variable activity, distribution, and combinations of carbapenemases.

Background: Neurolisteriosis due to Listeria monocytogenes is uncommon but associated with high morbidity and mortality. Diagnosis is often delayed due to heterogeneous clinical presentations, overlap with non-infectious neurological conditions and limited sensitivity of early diagnostic tests. Methods: We conducted a single centre retrospective chart review at a tertiary care teaching hospital between January 2024 to March 2026. Adult patients (≥ 18 years) with microbiologically confirmed neurolisteriosis cases were included. Clinical, radiological, microbiological, treatment, and outcome data were analysed descriptively. Results: Of the 1633 CSF samples analysed, 110 (6.7%) were positive for bacterial meningitis, of which 3 (2.7%) were due to Listeria monocytogenes . The median age of patient was 57 years (range: 30–69) with female predominance. One patient had SLE on immunosuppressive therapy while other two were immunocompetent. The median symptoms duration prior to admission was 1 day with common presenting symptoms headache, fever and altered sensorium. Imaging demonstrated hyperintense meningeal or parenchymal enhancement. CSF revealed neutrophilic pleocytosis, elevated protein, and low glucose. CSF and blood cultures were positive in all cases. Delayed appropriate therapy led to deterioration, but targeted ampicillin-based treatment resulted in favourable outcomes. Conclusions: Neurolisteriosis remains a significant diagnostic challenge due to its variable clinical presentation; therefore, maintaining a high index of suspicion and ensuring early recognition with prompt initiation of ampicillin-based therapy are essential for improving patient outcomes.

Non-tuberculous mycobacteria (NTM)/atypical mycobacteria are opportunistic pathogens ubiquitous in the environment. Recently, NTM cases causing skin and soft tissue infections are on the rise, owing to the improved diagnostic techniques as well as heightened number of procedures. A man in the mid 60s with diabetes, on insulin for the past 20 years, presented with multiple painful swellings, a few of them with pus discharge, over the insulin injection sites of arms, abdomen and thighs for the past 10 months. Local ultrasonography revealed anechoic collections surrounding increased vascularity in the subcutaneous planes. Histopathology showed suppurative inflammation with a large area of necrosis in the lower dermis and subcutaneous fat. Acid-fast bacilli culture grew NTM and was identified as Mycobacterium lentiflavum by PCR followed by Sanger sequencing of the 16S–23S intergenic spacer region. The lesions dramatically improved with clarithromycin and ofloxacin, which were continued for a total of 5 months.

Burkholderia thailandensis is an environmental Gram-negative bacterium closely related to the highly pathogenic B. pseudomallei, the causative agent of mel