- Volume 1, Issue 4, 2019
Volume 1, Issue 4, 2019
- Research Article
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Growth and metabolic characterization of four lactic acid bacteria species isolated from rice beer prepared in Assam, India
More LessIsolation and identification of lactic acid bacteria (LAB) from rice beer prepared in Assam, India was performed and their growth associated and functional properties were studied. LAB strains were identified as Lactobacillus casei , Pediococcus pentosaceus , Lactobacillus pentosus and Lactobacillus plantarum based on 16 s rRNA sequencing. Their growth characteristics at different pH, NaCl concentration, temperature and presence of carbohydrates were profiled. High tolerance against acid and bile salts was shown by all the strains, particularly L. pentosus TEZU174 and P. pentosaceus TEZU199 up to a pH of 1.5, and L. pentosus TEZU174 up to 14 % bile concentration. They were susceptible towards the common antibiotics, wherein erythromycin, chloramphenicol and linezolid were the most effective. The strains displayed antibiosis activity against Escherichia coli and Staphylococcus aureus and antioxidant activity in terms of resistance to H2O2, scavenging of ·OH and DPPH free radicals was also displayed, wherein L. casei TEZU374 and P. pentosaceus TEZU482 were the most effective with above 70 % scavenging activity. The strains displayed cellular aggregation and L. casei TEZU262 and L. casei TEZU309 were highly aggregated, which attained 100 % autoaggregation within a period of 5 h. High cell surface hydrophobicity was shown by L. casei TEZU309 towards xylene and chloroform, and P. pentosaceus TEZU427 towards ethyl acetate. The strains evinced good gut tolerance capacity, antioxidant activity and adherence properties, which are characteristics of probiotic bacteria and thus are candidates for therapeutic uses and also to be used as starter cultures.
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Ocins database: a database of bug-busters from Bifidobacterium, Lactobacillus, and Enterococcus
More LessThe ocins are antimicrobial polypeptides produced by probiotic microbes, such as Lactobacillus , Enterococcus , Streptococcus , Leuconostoc and Bifidobacterium . They are produced in response to stress and for the self-defense of the bacterium. It is indispensable to understand their mechanistic characteristics, structures, and functions, if the food industry is to reduce contamination levels and produce germfree foods. Databases of the ocins that are readily accessible to the food industry are scarce, but urgently required. Therefore, we established a very useful, unique, and a simple ocin database, which not merely provides information about ocins, but also directs their utilisation in the food industry. The database includes information about each ocin, its amino acid sequence, molecular weight, and isoelectric point. The database also possesses all the currently known ocin (probiotic origin only) sequences and structures, target organisms, and relevant to food industries (aqua culture, dairy and meat industries), which is hard to obtain in other databases. The database is free for public and accessed at http://ocins.cftri.com/ocins/.
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- Short Communication
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Comparison of semiquantitative and differential time to positivity methods for the diagnosis of central line-associated bloodstream infections in an intensive care unit
Introduction. Central line-associated bloodstream infections (CLABSIs) adversely affect patients’ hospitalization.
Aim. We compared semiquantitative roll plate (SQRP) and differential time to positivity (DTP) culture methods in diagnosing CLABSIs.
Methodology. A retrospective study was conducted in an intensive care unit (ICU) from January 2013 to August 2014. All ICU patients with suspected CLABSIs were included. Blood cultures were taken, while central venous catheter (CVC) tips were cultured using the roll-tip method. DTP was considered positive if CVC lumen blood cultures became positive at least 2 h prior to concurrently drawn peripheral blood cultures with an identical micro-organism. SQRP method was considered positive when ≥15 c.f.u. of a micro-organism identical to that of blood cultures grew. Measures of diagnostic accuracy were calculated.
Results. SQRP displayed high sensitivity (94.7 %), while DTP showed high specificity (82.5 %). SQRP combined with DTP displayed 100 % sensitivity and negative predictive value.
Conclusion. SQRP and DTP methods should be evaluated in combination.
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Effect of various bacteriological media on the plaque morphology of Staphylococcus and Vibrio phages
The influence of media composition on the life cycle of bacteriophages to exhibit diverse plaque morphology on various bacteriological media was investigated by a double agar overlay method. Both Staphylococcus aureus phage and Vibrio parahaemolyticus phage showed altered plaque morphology from small to large and from clear to turbid, in different culture media used for the double agar overlay method.
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- Case Report
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First case report of pulmonary and cutaneous nocardiosis caused by Nocardia mexicana in Iran
More LessBackground . Nocardia are aerobic partially acid-fast bacteria that are environmentally ubiquitous. This group of bacteria causes a rare bacterial infection of either the lungs (pulmonary) or body (systemic) that usually affects immunocompromised individuals. Nocardia mexicana was first isolated in 2004 from a patient with chronic bronchitis. However, there have been few reports on the clinical significance of this organism up to now. We herein report the first cases of N. mexicana in patients with pulmonary and cutaneous infection from Iran.
Case presentation. A 57-year-old man was admitted to hospital due to a cutaneous wound on his left foot, fever, weakness, persistent cough and chest pain. At first, due to clinical examination and laboratory test, the patient was diagnosed as having tuberculosis. However, PCR of Mycobacterium tuberculosis was negative from broncho-alveolar lavage (BAL) samples. Direct PCR of BAL was performed for this patient and according to the clinical examinations and microbiological evaluations; the micro-organism was identified as N. mexicana and was isolated from both BAL and the wound. Finally, the patient was treated with linezolid and amikacin.
Conclusions. The infections, with actinomycetes such as Nocardia , are easily neglected or misdiagnosed due to the fastidious nature of the organism and the inadequate microbiological experience of laboratories in the hospitals of developing countries. This case shows that hospitals should consider a better laboratory protocol to deal with the clinical cases in which fastidious organisms, and in particular Nocardia , are involved.
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