Phenotypic Identification Of Bacteria Research Articles

Identification of Proteus Vulgaris using Series of Biochemical Test and Staining Technique: Ecology, Pathogenicity (Enteric Pathogen), Description and Prevention of It’s Diseases

Phenotypic identification of bacteria by staining technique and biochemical tests. This practical was carried out to identify Proteus vulgaris using biochemical test, this test includes, citrate utilization, indole, carbohydrate fermentation, methyl red, voges Proskauer, motility, production of hydrogen sulphide, catalase, and oxidase tests. Results obtained shows that Proteus vulgaris was positive to indole, motility, methyl red and urease. Proteus vulgaris was unable to utilize citrate for carbon and energy, and does not synthesis the enzyme amylase to break down starch. The bacteria fermented glucose to produce acid and gas.

Identification of the nasopharyngeal carriage of Neisseria meningitidis by 16S rRNA Gene sequencing in asymptomatic adolescents and young adults in Cartagena, Colombia (2019–2020).

The bacterium Neisseria meningitidis, a strictly human pathogen, can cause meningitis, meningococcemia, sepsis, and death; repeatedly it scause outbreaks around the world. The frequency of asymptomatic carriage is often high in adolescents and young adults, increasing the invasive meningococcal disease risk and likelihood of transmission. However, detailed analyses of meningococcal carriage in this population in Colombia, particularly in coastal areas, are lacking. In this study, the prevalence and characteristics of Neisseria meningitidis carriage were evaluated in asymptomatic adolescents and young adults (11-25 years old) in Cartagena, Colombia. Oropharynx samples were collected from participants between August and December 2019. The phenotypic identification of bacteria was performed by conventional methods and biochemical testing. Molecular identification to the species level was performed by 16S rRNA gene sequencing. In total, 12 of 648 samples were positive for Neisseria meningitidis by 16S rRNA sequencing, indicating a prevalence of 1.9%. Isolates were classified into four invasive serogroups (A, B, C, and W) by a comparative sequence analysis of the ribosomal gene. Despite the occurrence of meningococcal disease in Cartagena city in the last several years, the frequency of oropharyngeal carriage in adolescents and young adults was low. Serogroup A had not been previously reported in nasopharyngeal samples in Colombia. This is the first report of Neisseria meningitidis on the Colombian Caribbean coast based on 16S rRNA sequencing and is expected to guide the development of vaccination and follow-up strategies.

Phenotypic identification of bacteria of the family Enterobacteriaceae with resistance profile on inanimate surfaces in a University Hospital

The aim of this study was to identify bacteria belonging to the family Enterobacteriaceae with resistance profile on inanimate surfaces and utensils of sectors from a University Hospital of Pernambuco. Initially, the samples were collected on 25 inanimate surfaces and utensils of the Intensive Care Unit (ICU), Hemodialysis Center and Medical Clinic in 2018. The samples were plated on MacConkey and SS agar and incubated at 35 ± 2 °C for 24 hours. After incubation, they were submitted to biochemical tests to confirm the presence of bacteria to the family Enterobacteriaceae. Subsequently, Klebsiella pneumoniae carbapenemase (KPC) was identified by the disc diffusion method, as well as by Hodge test; extended-spectrum beta-lactamase producing bacteria (ESBL) by the disk diffusion and double disk diffusion tests; and metallo-beta-lactamase producing bacteria (MBL) through the disc diffusion method according to the Clinical and Laboratory Standards Institute (CLSI). Eight surfaces or utensils of the 18 samples with Enterobacteriaceae presented resistance profile (44.4%). KPC was identified in 46.7% of the samples that presented bacteria with resistance profile, one presented simultaneously KPC and ESBL (6.65%), another one KPC and MBL concomitantly (6.65%) and 6 samples presented only ESBL (40%). Medical Clinic and Hemodialysis Center had the highest presence of resistant Enterobacteriaceae. The detection of resistant microorganisms in hospitals is worrying and emphasizes the importance of health professionals in acquiring knowledge about preventive measures to minimize hospital infections.

Rapid differentiation of bacterial species by high resolution melting curve analysis

Molecular based differentiation of various bacterial species is important in phylogenetic studies, diagnostics and epidemiological surveillance, particularly where unusual phenotype makes the classical phenotypic identification of bacteria difficult. Molecular approach based on the sequence of 16S ribosomal RNA gene analysis can achieve fast and reliable identification ofbacteria. High resolution melting (HRM) curve analysis has been developed as an attractive novel technique for DNA sequence discrimination but it's application for bacteria differentiation has not been well studied yet. W have developed HRM assay for differentiation of sixteen pathogenic or opportunistic bacterial species. Amplified partial 16S ribosomal RNA gene region between 968 and 1401 positions (E. coli reference numbering) was subsequently used in high resolution melting curve analysis of PCR products for bacterial species differentiation. Sixteen bacterial species were simultaneously discerned by difference plot of normalized and temperatures shifted melting curves, without need for spiking of DNA, hetero-duplexing experiments or application of several primer pairs. High resolution melting curve analysis of duplex DNA is simple, fast and reliable tool for bacterial species differentiation and may efficiently complement phenotypic identification ofbacteria.

Molecular Detection of Multiple Emerging Pathogens in Sputa from Cystic Fibrosis Patients

BackgroundThere is strong evidence that culture-based methods detect only a small proportion of bacteria present in the respiratory tracts of cystic fibrosis (CF) patients.Methodology/Principal FindingsStandard microbiological culture and phenotypic identification of bacteria in sputa from CF patients have been compared to molecular methods by the use of 16S rDNA amplification, cloning and sequencing. Twenty-five sputa from CF patients were cultured that yield 33 isolates (13 species) known to be pathogens during CF. For molecular cloning, 760 clones were sequenced (7.2±3.9 species/sputum), and 53 different bacterial species were identified including 16 species of anaerobes (30%). Discrepancies between culture and molecular data were numerous and demonstrate that accurate identification remains challenging. New or emerging bacteria not or rarely reported in CF patients were detected including Dolosigranulum pigrum, Dialister pneumosintes, and Inquilinus limosus.Conclusions/SignificanceOur results demonstrate the complex microbial community in sputa from CF patients, especially anaerobic bacteria that are probably an underestimated cause of CF lung pathology. Metagenomic analysis is urgently needed to better understand those complex communities in CF pulmonary infections.