A Fatal Case of Multidrug-Resistant Pleural Nocardiosis by Nocardia otitidiscaviarum in an Immunosuppressed Patient: A Case Report and Literature Review.

Nocardiosis is known as an opportunistic infection in immunocompromised hosts. We present to you a case of pleural nocardiosis in a 38-year-old male patient who was a chronic smoker and presented with a left-sided pleural effusion. He was a known case of thrombocytopenia due to immune thrombocytopenia (ITP) and was on steroid therapy. On admission, he was found to be positive for HIV. Pleural fluid was sent to microbiology, where acid-fast staining with 1% sulfuric acid (H2SO4)showed acid-fast branching filamentous rods and cultures grew Nocardia, which was resistant to ampicillin, ceftriaxone, imipenem, cotrimoxazole, erythromycin, tetracycline, and susceptible to amikacin, linezolid, and levofloxacin. The isolate was identified as Nocardia otitidiscaviarum using 16S rRNA gene sequencing. Culture from the chest wall drain grew Escherichia coli and Stenotrophomonas maltophilia. Subsequently, the patient developed sepsis, and paired blood cultures grew Candida guilliermondii. Unfortunately, the patient could not survive despite aggressive efforts and died after 40 days of admission.

Structural insights of a putative ß-1,4-xylosidase (PsGH43F) of glycoside hydrolase family 43 from Pseudopedobacter saltans.

Structural and conformational insights of a putative ß-1,4-xylosidase (PsGH43F) of glycoside hydrolase family 43 from Pseudopedobacter saltans were investigated by computational and Circular Dichroism (CD) analyses. PsGH43F was cloned and expressed in E. coli BL21 (DE3) cells and the purified enzyme gave the size ~50 kDa on SDS-PAGE analysis. Multiple Sequence Alignment of PsGH43F sequence followed by superposition of modeled structure with homologous structures displayed the presence of three conserved catalytic amino acid residues, Asp33, Asp149 and Glu212. The secondary structure analysis by CD showed 2.72 % α-helix and 36.06 % ß-strands. The homology modeled structure of PsGH43F displayed a 5-bladed ß-propeller fold for catalytic module at N-terminal and a ß-sandwich structure for CBM6 at the C-terminal. Ramachandran plot displayed 99.5 % of residues in the allowed regions. MD simulation of PsGH43F revealed the compactness and stability of the structure. Molecular docking studies of PsGH43F with xylo-oligosaccharides revealed its maximum binding affinity for xylobiose. MD simulation of PsGH43F-xylobiose complex confirmed the increased structural and conformational stability in presence of substrate. The Hydrodynamic diameter analysis of PsGH43F by DLS was in the range, 0.25-0.28 µm.

Clinical correlation and antimicrobial susceptibility pattern of Chryseobacterium spp.: A three year prospective study.

Chryseobacterium species are widely distributed in the environment. They are rarely found in hospital settings causing nosocomial infections. Limited data is available regarding their epidemiology, clinical significance and antimicrobial susceptibility patterns. This study was aimed to identify different species of Chryseobacterium using matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) and to correlate clinically with antimicrobial susceptibility patterns in a tertiary care hospital in north India. We also performed phenotypic tests, which may be useful to differentiate this bacterium from other non-fermenters. A total of 20 isolates of Chryseobacterium spp. were identified over a period of 3 years. Chryseobacterium indologenes (18/20) was the most common species isolated followed by Chryseobacterium gleum (2/20) from various clinical samples. Antimicrobial susceptibility testing (AST) was performed. Susceptibility to rifampicin was observed at a maximum (75%) followed by piperacillin-tazobactum (45%). Susceptibility against imipenem, meropenem, cotrimoxazole and cefoperazone-sulbactum were observed approximately 33%. Amikacin, cefotaxime and ceftazidime showed least susceptibility results. Further clinical correlation was established.

Breast abscess due to Salmonella paratyphi A : Case reports with review of literature.

Salmonella paratyphi A causes paratyphoid fever which is characterized by acute onset of fever, abdominal pain, diarrhoea, nausea and vomiting. Localized disease can occur following both overt and silent bacteremia followed by seeding of bacteria at distant sites. Salmonella species though associated with abscess formation in various organs,are rarely associated with breast abscess. We report 2 cases of breast abscess due to Salmonella enterica serotype paratyphi A. Appropriate sampling, surgery supplemented by a comprehensive microbiological work up aided in pathogen identification and appropriate antibiotic administration for a successful outcome of these patients.