Transcriptomic responses of XDR Klebsiella pneumoniae to N-acetyl cysteine reveals suppression of major biogenesis pathways leading to bacterial killing and biofilm eradication.

AIMS: Carbapenemase-producing K. pneumoniae is categorized as a "critical global priority-one" pathogen by WHO and new and efficient treatment options are warranted. This study aims to assess the antibacterial and antibiofilm potential of N-acetyl cysteine (NAC), against clinical isolates of extensively drug resistant (XDR) K. pneumoniae and elucidate the mechanism of killing. METHODS AND RESULTS: XDR-K. pneumoniae were isolated from patients admitted to Madras Medical Mission Hospital, India. Antibiofilm activity of NAC was checked using in vitro continuous flow model and RNA sequencing was done using Illumina Novoseq. Data quality was checked using FastQC and MultiQC software. Our findings revealed that NAC at a concentration of 100 mg/mL was safe, and could inhibit the growth and completely eradicate mature biofilms of all XDR- K. pneumoniae isolates. Transcriptomic responses in XDR- K. pneumoniae to NAC showed significant downregulation of the genes associated with crucial biogenesis pathways including electron transport chain and oxidoreductase activity besides a specific cluster of genes linked to ribosomal proteins. CONCLUSIONS: Our results indicate that NAC kills the XDR- K. pneumoniae clinical isolates by shutting the overall metabolism and hence, successfully eradicate in vitro biofilms formed on catheters.

Genome analysis of clinical isolate of Campylobacter fetus subspecies fetus MMM01 from India reveals genetic determinants of pathogenesis and adaptation.

In this study we report the whole genome sequencing (WGS) based analysis of blood-borne Campylobacter fetus subsp. fetus MMM01 isolated from a diabetic patient to obtain deeper insights in to the virulence and host adaptability. The sequenced genome of C. fetus subsp. fetus MMM01 along with reference genomes retrieved from NCBI was subjected to various in-silico analysis including JSpecies, MLST server, PATRIC server, VFanalyzer, CARD, PHASTER to understand their phylogenetic relation, virulence and antimicrobial resistance profile. The genome had a size of 1,788,790 bp, with a GC content of 33.09%, nearly identical to the reference strain C. fetus subsp. fetus 82-40. The MLST based phylogenetic tree constructed revealed the polyphyletic branching and MMM01 (ST25) was found to be closely related to ST11, both belong to the sap-A serotype which are more common in human infections. VFanalyzer identified 88 protein-coding genes coding for several virulence factors including Campylobacter adhesion to fibronectin, flagellar apparatus, cytolethal distending toxin operons and Campylobacter invasion antigen proteins which enhance the virulence of bacteria along with resistance genes against antibiotics including fluoroquinolone, chloramphenicol, tetracycline, and aminoglycoside in MMM01, which points to enhanced survival and pathogenicity of this zoonotic pathogen. It was interesting to find that MMM01 lacked FGI-II island found in most of the clinical isolates, which encoded CRISPR Cas and prophage II regions. More details about the complexity and evolution of this zoonotic pathogen could be learned from future studies that concentrate on comparative genome analysis using larger genome datasets.

Reprocessing of N95 masks: Experience from a resource-limited setting in India.

OBJECTIVES: Due to the surge in demand for N95 masks during the Covid-19 pandemic, and considering the situation in countries grappling with acute shortages of N95 masks, this study investigated the possibilities of decontamination and reuse of masks. METHODS: Three N95 masks of different makes (A, B and C) were subjected to six decontamination methods: ultraviolet (UV) irradiation, isopropyl alcohol (IPA) dip, plasma sterilization (Sterrad®), ethylene oxide (ETO, 3M®), dry heat sterilization, and moist heat sterilization (autoclaving). The integrity of the N95 masks was assessed by measuring their particle filtering efficiency at particle sizes ranging 0.3-0.5 microns. RESULTS: All the masks decontaminated with ETO and plasma sterilization retained over 95% particle filtering efficiency. Masks decontaminated using IPA dip and autoclaving showed a drop, and UV irradiation showed variations in particle size efficiency degradation after decontamination. CONCLUSIONS: Plasma sterilization is recommended for decontamination of N95 masks in low-resource settings. ETO is not recommended due to hazards associated with handling of ethylene oxide, although the filtering efficiency was retained. Since the UV irradiation method showed variations in results, evaluation of UV decontamination for N95 masks needs to be performed on a case-by-case basis.

Burkholderia vietnamiensis causing a non-lactational breast abscess in a non-cystic fibrosis patient in Tamil Nadu, India.

Burkholderia cepacia complex is a Gram-negative opportunistic pathogen usually found in people with an immunocompromised condition such as cystic fibrosis (CF). In a tropical country like India, this organism has been associated with a number of hospital-acquired infections including sepsis. We present here a report of a case of Burkholderia vietnamiensis causing a non-lactational breast abscess in a non-CF patient. The pathogen was identified as B. cepacia using Vitek system and matrix-assisted laser desorption ionisation-time of flight. This was confirmed by polymerase chain reaction (PCR) using recA genus-specific gene and sequencing of the PCR amplicons. recA-restriction fragment length polymorphism and recA gene sequencing revealed that the isolate is B. vietnamiensis. This is the first description of B. vietnamiensis isolated from a clinical case from India.

A rare association of Mycobacterium tuberculosis infection of kidney and urinary tract with immunoglobulin A nephropathy.

Mycobacterium tuberculosis(MTB)-related secondary immunoglobulin A (IgA) nephropathy is reported in a 72-year-old male patient. The patient was diagnosed to have MTB infection of the kidney and genitourinary tract which was diagnosed by the demonstration of the organism by GeneXpert Ultra and culture. Concurrent kidney biopsy showed IgA nephropathy. The patient responded to urethral double-J stenting and four-drug antituberculous therapy with improvement of kidney function and resolution of MTB. IgA nephropathy can present as primary glomerulonephritis or secondary to MTB infection.

Twenty-one episodes of peritonitis in a continuous ambulatory peritoneal dialysis patient: What is the root cause?

A 51-year-old female, with non-alcoholic liver cirrhosis, portal hypertension, type 2 diabetes mellitus, autosomal dominant polycystic kidney disease with a clipped cerebral aneurysm and chronic kidney disease stage 5 was on continuous ambulatory peritoneal dialysis (CAPD) for 6.5 years elsewhere. She came for opinion on continuation of CAPD as she had 21 episodes of peritonitis in 76 months. Her blood pressure was 80/50 mmHg. She was on haemodialysis with a temporary central access for 2 weeks. She had no abdominal tenderness, and exit site looked normal. Fluid was negative for Mycobacterium tuberculosis. Laparoscopically, we replaced the catheter with a new swan-neck Tenckhoff double-cuff catheter through a different exit site in the same sitting. Catheter-tip biofilm culture isolated Enterococcus casseliflavus. Peritoneal sampling biopsy showed evidence of fibrosis. She has adequate ultrafiltration and is currently on automated peritoneal dialysis for 5 months.

An unusual case of unresolving tunnel infection in a patient on continuous ambulatory peritoneal dialysis.

Atypical mycobacteria remain a rare cause of peritoneal dialysis catheter-related tunnel infection (TI) and poses serious risk because of the resistant nature to most antibiotic therapy. Non-tubercular mycobacterial infections lead to chronicity requiring peritoneal dialysis catheter removal. We report an 82-year-old male, with diabetic nephropathy who had a coinfection with Staphylococcus hominis and Mycobacterium abscessus who presented with pus discharge at exit site and TI. He was treated with relocation of the extraperitoneal part of the catheter with a new exit site without catheter removal and multidrug mycobacterial therapy.

Rare occurrence of fatal Candida haemulonii peritonitis in a diabetic CAPD patient.

A 68-year-old diabetic chronic kidney disease patient on continuous ambulatory peritoneal dialysis for two years developed Candida haemulonii peritonitis without any predisposing factors. There is no effective treatment for this fungus. A peritoneal biopsy showed morphological changes of acute inflammation and chronicity.