Unforeseeable presentation of Chryseobacterium indologenes infection in a paediatric patient

Qualification of Human Liver Microsomes for Antibacterial Activity Screening of Drug Metabolites

Microsomes are commonly used to perform in vitro drug metabolism, predominantly to form phase I drug metabolites. Pooled microsomes from multiple donors can contain microorganisms from underlying microbial diseases. Exposure to microbes can also occur during extraction if aseptic processing is compromised. Although microbial presence does not affect the metabolic activity of microsomes, presence of unwanted microorganisms can cause interference if the downstream application of microsomal drug metabolites is screening for antibacterial activity. In this work, traditional biochemical tests and advanced proteomics-based identification techniques were used to identify two gram-negative bacteria in pooled human liver microsomes. Several decontamination procedures were assessed to eradicate these two bacteria from the microsomes without affecting its metabolic capacity, and organic extraction was found to be the most convenient and efficient approach to decontaminate microsomes and screen drug metabolites for antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA).

Genomic analysis of Chryseobacterium indologenes and conformational dynamics of the selected DD-peptidase

Chrysobacterium indologenes is an emerging MDR pathogen that belongs to the family Flavobacteriaceae. The genome of the C. indologenes, isolated from the nephrotic patient, was sequenced through Illumina MiSeq. The pangenomics of available 56 C. indologenes strains using BPGA revealed an open pangenome (n=5553 CDS), core genome (2141), and accessory genome (2013). The CEG/DEG database identified 662 essential genes that drastically reduced to 68 genes after non-homology analyses towards human and gut microbiome. Further filtering the data for other drug target prioritizing parameters resulted in 32 putative targets. Keeping in view the crucial role played in cell wall biosynthesis, dacB was selected as the final target that encodes D-alanyl-d-alanine carboxypeptidase/endopeptidase (DD-peptidase). The 3D structure of dacB was modelled and rendered to docking analyses against two compound libraries of African plants (n=6842) and Tibetan medicines (n=52). The ADMET profiling exhibited the physicochemical properties of final compounds. The MD simulations showed the stability of inhibitor-DD-peptidase complex and interactions in terms of RMSD, RMSF, binding free energy calculation and H-bonding. We propose that the novel compounds Leptopene and ZINC95486338 from our findings might be potent DD-peptidase inhibitors that could aid in the development of new antibiotic-resistant therapy for the emerging MDR C. indologenes.

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.

Bacteremia by Chryseobacterium indologenes in a Patient with Lung Cancer: A Clinical and Microbiological Investigation

We present a case of bacteremia by an unsual, instrinsically multidrug resistant organism, Chryseobacterium indologenes in a 59 year old gentleman with squamous cell carcinoma of lung with multiple metastasis. Despite of treating as per sensitivity report after isolatingChryseobacterium indologenes, patient could not be survived. The pathogenicity and predictability of the organism towards antibiotics, bothin vivo and in vitro needs further research.

How to cite this article

Bhagawati G, Bhardwaj A et al. Bacteremia by Chryseobacterium Indologenes in a Patient with Lung Cancer: A Clinical and Microbiological Investigation. Indian J Crit Care Med 2019;23(3):157-159.

Molecular Characterization of Chryseobacterium indologenes with Multidrug Resistance in the Brazilian Amazon Region

Chryseobacterium indologenes is an emerging nosocomial pathogen that produces IND-type chromosomal metallo-beta-lactamase. The phenotype and molecular aspects of two multidrug resistant C. indologenes strains and the analysis of the tertiary structure of the IND enzyme were studied. Identification of species and susceptibility tests were performed using the Vitek-2 compact. Chromosomal and plasmid DNA were extracted using PureLink™ Genomic DNA Mini Kit and PureLink Quick Plasmid Miniprep Kit, and the sequencing was performed using ABI 3130 genetic analyzer. Two strains were isolated and are registered as P-23 and P-113. Of the two, P-113 was sensitive to ciprofloxacin and cefepime only, whereas the P-23 showed reduced sensitivity to ceftazidime, ciprofloxacin, and tigecycline. The genetic analysis of both isolates identified the presence of the bla_IND-like gene, with similarity to IND-3 and IND-8 alleles. The IND-3 identified in the P-133 sample presented a single mutation at position T355G, which corresponds to a nonsynonymous substitution of the amino acid at position 119 (Ser→Ala). The phylogenetic analysis of INDs showed lineages that are circulating in Asian and European countries. These results emphasize the need for effective preventive actions to avoid the dissemination of this type of pathogen in the hospital environment.

Clinical Strains of Chryseobacterium and Elizabethkingia spp. Isolated from Pediatric Patients in a University Hospital: Performance of MALDI-TOF MS-Based Identification, Antimicrobial Susceptibilities, and Baseline Patient Characteristics

Our objective was to evaluate the performance of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) for identification of the Chryseobacterium and Elizabethkingia spp. isolated from pediatric patients at Hacettepe University Hospital using 16S rRNA gene sequencing as the gold standard and to determine the antimicrobial susceptibility patterns of the isolates and baseline characteristics of patients. All stored Chryseobacterium and Elizabethkingia spp. isolated from various clinical specimens (sputum, blood, and urine) of pediatric patients at Hacettepe University Hospital between 2012 and 2016 were included in this study. Minimum inhibitory concentrations of 10 antimicrobial agents were determined by Etest for all isolates. To determine the baseline characteristics of patients, medical records of all patients were retrospectively reviewed. In total, 18 isolates of Chryseobacterium spp. (16 C. indologenes, 2 C. gleum) and 5 isolates of Elizabethkingia spp. (3 E. meningoseptica, 2 E. anophelis) were identified by 16S rRNA sequencing. MALDI-TOF MS correctly identified 19 (82.6%) isolates to the species level. The quinolones (ciprofloxacin and levofloxacin), trimethoprim/sulfamethoxazole and piperacillin/tazobactam showed the highest spectrum of activity against the overall collection of isolates. Cystic fibrosis (CF) was the underlying disease in 81.8% of patients. To our knowledge, this study includes the largest number of Chryseobacterium spp. isolated from clinical specimens of pediatric patients in Turkey. In this study, we also report the first clinical isolate of E. anophelis in Turkey. Since, the majority of strains were isolated from patients with CF; larger, prospective clinical studies are needed to establish whether chryseobacteria could be considered as an emerging opportunistic pathogen in patients with CF.

Challenges in the identification of Chryseobacterium indologenes and Elizabethkingia meningoseptica in cases of nosocomial infections and patients with cystic fibrosis

Rare nonfermenting Gram-negative bacilli, such as Chryseobacterium indologenes and Elizabethkingia meningoseptica, have clinical importance in nosocomial infections and cystic fibrosis (CF), and their identification is a challenge to microbiology laboratories. Thus, the objective of this study was to verify the performance of phenotypic and mass spectrometry (matrix-assisted desorption ionization–time of flight mass spectrometry, MALDI-TOF MS) methods to identify C. indologenes and E. meningoseptica. In this context, the results obtained with phenotypic methods—namely manual biochemical and automated VITEK 2 (bioMérieux, Marcy l’Etoile, France) and Phoenix tests (Becton Dickinson (BD), San Diego, CA, USA)—and by MALDI-TOF MS—namely MALDI-TOF VITEK MS (MALDI-MS; bioMérieux) and MALDI-TOF BioTyper (MALDI-BD; BD)—of 22 isolates (blood cultures of patients with nosocomial infection (n = 15) and from patients with CF (n = 7)), initially identified as C. indologenes and E. meningoseptica, were compared. As result, using the manual phenotypic method, it was possible to identify the species level in 18/22; no identification was found in 4/22. There was a low agreement level between manual and VITEK 2 automated phenotypic methods when considering the genus level. The greatest agreement for genus-level identification occurred in MALDI-TOF MS equipment (15/22). When comparing all methods to identify the 22 isolates, there was agreement of 4/22 at the genus level and of 4/22 at the species level. In conclusion, there is low agreement level among identification methods of C. indologenes and E. meningoseptica. Although MALDI-TOF MS equipment shows a higher agreement level among them, results present low levels of confidence.

Chryseobacterium Indologenes Pneumonitis in an Infant: A Case Report

Chryseobacterium indologenes, a non-fermentative Gram-negative bacilli distributed widely in nature, is an emerging nosocomial pathogen, inherently resistant to a wide range of antibiotics. There is limited number of C. indologenes infections reported from India. We report a case of C. indologenes associated pneumonia in a three-month-old infant with congenital heart disease. This case highlights the importance of prompt diagnostic workup and targeted antibiotic therapy for its effective management.

Ventilator-associated pneumonia caused by Chryseobacterium indologenes: a rare infant case and review of the literature

Background

Chryseobacterium indologenes is an uncommon organism that has been documented to cause a variety of invasive infections mostly in hospitalized patients with severe underlying diseases.

Case presentation

A three-month-old female infant born at term by caesarean section with meningomyelocele and congenital diaphragmatic hernia had two surgeries for the repair of meningomyelocele and diaphragmatic hernia on her 3rd and 14th day, respectively. On the 3rd month of her life, she deteriorated clinically with fever, leukocytosis and increase of acute-phase reactants. Gas exchange condition became worse than it was before. Respiratory secretions, oxygen requirements and ventilator demand increased. Chest X-ray showed bilateral pulmonary infiltrates. Bacteriological blood, urine and cerebrospinal fluid culture test results were negative. C. indologenes was isolated from tracheobronchial secretion sample obtained by endotracheal aspiration. Although susceptible to ciprofloxacin (MIC:0.5 gr/L), levofloxacin and piperacillin–tazobactam, the isolate was resistant to meropenem, imipenem and colistin. She was treated with ciprofloxacin successfully. Her fever resolved and gas exchange condition improved after 72 h of the treatment. The antibiotic treatment was given for a course of 14 days.

Conclusion

Chryseobacterium indologenes may emerge as a potential pathogen in infants with the factors such as invasive equipment, having underlying diseases and prolonged hospitalization.