Assessment of genetic diversity of brinjal (Solanum melongena L.) germplasm by RAPD markers

Assessment of genetic diversity in a crop species is prerequisite to its improvement. The use of germplasm with distinct DNA profiles helps to generate genetically diversified breeding populations. The present study was carried out to investigate the genetic diversity in brinjal or eggplant (Solanum melongena L.) using random amplified polymorphic DNA (RAPD). Fifteen brinjal germplasm and three decamer primers were used for random polymorphic DNA assay. A total of 17 fragments were obtained, out of which 12 (70.59%) were polymorphic. Each primer generated 4 to 8 amplified fragments with an average of 5.67 fragments per primer. The highest genetic distance (0.8873) and the lowest genetic identity (0.4118) were observed in Laffa (Elongated) versus Jessore L and Dharola combinations. The lowest genetic distance (0.1525) was observed in several cultivars. The unweighted pair-group method of arithmetic means (UPGMA) dendrogram was constructed from genetic distance and all brinjal cultivars were grouped into five clusters. The genetic diversity of brinjal cultivars reported in this study will be useful when planning future crosses amongst these cultivars

Emergence of carbapenemase-producing urinary isolates at a tertiary care hospital in Dhaka, Bangladesh

AbstractObjectivesA growing incidence of pathogens producing carbapenemases has been observed in many countries including Bangladesh. The present study was carried out to determine the presence of carbapenemase producers among uropathogens.Materials and MethodsA total of 138 Gram-negative uropathogens were isolated and identified by conventional methods and were screened for carbapenemase production using imipenem discs. Phenotypic identification of carbapenemase production was done by the double disc synergy test, combined disc assay, and modified Hodge test. The minimum inhibitory concentration of imipenem was determined by the agar dilution method. Genes encoding blaNDM-1, blaIMP, blaVIM, blaKPC and blaOXA-48/blaOXA-181 were identified by polymerase chain reaction.ResultsTwenty (14.49%) imipenem resistant strains were detected among 138 Gram-negative uropathogens. The most common isolates were Escherichia coli and Klebsiella spp. Among 20 imipenem resistant strains, 16 (80%) carbapenemase producers were detected by polymerase chain reaction, 13 (65%) by double disc synergy, 15 (75%) by combined disc assay, and seven (35%) by modified Hodge test. The blaNDM-1 gene was most prevalent (55%), followed by blaOXA-48/OXA-181, blaKPC (20%), blaVIM (15%), and blaIMP (10%). More than one carbapenemase gene was present in nine (45%) of the isolates. The minimum inhibitory concentration of imipenem of the carbapenemase producers ranged from ≥128 μg/mL to 4 μg/mL. Overall, carbapenemase encoding genes were detected in 11.6% (16/138) of the studied Gram-negative uropathogens. All (100%) of the carbapenemase-producing organisms were resistant to all tested antibiotics apart from colistin.ConclusionThe study shows a significant rate of urinary isolates were carbapenemase producers, including a high prevalence of blaNDM-1, in Bangladesh

Detection of OXA-181/OXA-48 carbapenemase producing Enterobacteriaceae in Bangladesh

Carbapenem resistant Enterobacteriaceae (CRE) is becoming a major public health concern globally. Detection of carbapenem hydrolyzing enzyme carbapenemase in Enterobacteriaceae is important to institute appropriate therapy and to initiate preventive measures. This study was designed to determine the presence of carbapenemase producers among the CRE isolated from patients at Dhaka Medical College Hospital, Bangladesh. Twenty-nine CRE strains detected by disk diffusion technique were included in the study. Minimum inhibitory concentration of imipenem and tigecycline was determined by agar dilution method. Carbapenemase production was phenotypically detected by Modified Hodge test while MBL producers were detected by combined disk and double disk synergy tests. Genes encoding blaNDM-1, blaOXA-181, blaOXA-48, blaKPC, blaCTX-M-15, blaOXA-1-group were identified by polymerase chain reaction (PCR). Out of 29 CRE, nineteen (65.6%) were positive for carbapenemase by any of the three phenotypic tests namely MHT, CD or DD tests. Those 19 isolates were also positive either for blaNDM-1 or blaOXA-181/blaOXA-48 by PCR. Of the 19 PCR positive isolates, the rate of positivity for blaNDM-1, blaOXA-181/blaOXA-48 and blaNDM-1+ blaOXA-181/blaOXA-48 was 73.7% (14/19), 57.9% (11/19) and 31.6% (6/19) respectively. Both blaOXA-181 and blaOXA-48 co-existed. All the carbapenemase producing organisms harboured blaCTX-M-15 except one C. freundii strain. The rate of resistance to different classes of antibiotics ranged from 63.2% to 100% except colistin and tigecycline. Organisms positive for OXA-181/OXA-48 had a low level of resistance to carbapenem (MIC 1 - 4 μg/ml) while with NDM-1 had high level resistance to imipenem (MICs 16 - ³ 32 μg/ml). Out of 19 carbapenemase positive isolates, 12 (63.16%) were extensively drug-resistant (XDR) and were only sensitive to tigecycline and colistin. The result of this study showed the presence of blaOXA-181/ blaOXA-48, blaNDM-1 positive strains in Bangladesh and colistin and tigecycline were the most effective drugs against carbapenemase producing Enterobacteriaceae (CPE). Epidemiological monitoring of carbapenemase producing organisms in Bangladesh is important to prevent their dissemination. Ibrahim Med. Coll. J. 2015; 9(2): 48-5

Molecular detection of atypical microorganisms in patients with ventilator associated pneumonia

Ventilator-associated pneumonia (VAP) is one of the major causes of morbidity and mortality among the critically ill patients of intensive care units (ICU). The present cross sectional study was conducted to isolate and identify bacterial causes of VAP among the patients admitted in intensive care unit (ICU) of Dhaka Medical College Hospital. The study was conducted between July, 2013 to June 2014. A total of 65 endotracheal aspirate (ETA) and blood samples were collected from patients with clinically suspected ventilator associated peumonia(VAP). Samples were collected from patients on mechanical ventilation for more than 48 hours. ETA and blood samples were cultured aerobically. Multiplex PCR was performed with ETA to detect Mycoplasma pneumoniae, Legionella pneumophila and Chlamydia pneumoniae. Among the atypical bacteria, M. pneumoniae were detected in 5 (7.69%), L. pneumophila in 4 (6.15%) cases by multiplex PCR in ETA from VAP cases. No C. pneumoniae was detected. The study revealed that in VAP cases atypical bacteria should be considered as a possible bacterial agents. Ibrahim Med. Coll. J. 2015; 9(1): 22-2

Antimicrobial Susceptibility Pattern and Virulence Genes Detection in Citrobacter freundii Isolated from Patients of a Tertiary Care Hospital, Bangladesh : Antimicrobial susceptibility pattern and virulence genes detection in Citrobacter freundii

Background: Citrobacter freundii is an infrequent hospital acquired pathogen to cause different types of disease in clinical settings. This pathogen is associated with wide range of infections causing unpredictably high mortality rate of 30-60%.  Separation of this pathogen in health care settings is escalating and multidrug resistant strains are emerging. Therefore, this study aimed to detect antimicrobial resistance pattern and virulence genes among the isolated C. freundii. Methods: A total 500 samples (urine, stool, wound swab & pus, blood endotracheal aspirates and sputum) from patients with clinically suspected infections irrespective of age and sex were used in this study. Disc diffusion method was used to detect susceptibility pattern of antibiotics; colistin, tigecycline and fosfomycin susceptibility pattern was identified by minimum inhibitory concentration (MIC) method. Polymerase chain reaction (PCR) was done to detect potential virulence genes. Results: Among 27 isolated C. freundii, majority were resistant to amoxiclav (92.59%), trimethoprim-sulfomethoxazole (88.89%), cefotaxime and ceftazidime (85.19%) followed by ceftriaxone (81.48%), cefepime and ciprofloxacin (77.78%). MIC showed least resistance to colistin (29.63%), fosfomycin (11.11%) and tigecycline (7.41%). PCR was positive for via B gene (48.15%)   and lt-A gene (25.93%). hly A, lt, lt-h genes showed negative results. Conclusion: Antibiotic resistance found in this study is quite worrisome as widespread resistance is seen among the bacteria isolated from human infection. Also, virulence genes play important role in C. freundii infection

Assessment of genetic diversity of brinjal ( Solanum melongena

Assessment of genetic diversity in a crop species is prerequisite to its improvement. The use of germplasm with distinct DNA profiles helps to generate genetically diversified breeding populations. The present study was carried out to investigate the genetic diversity in brinjal or eggplant (Solanum melongena L.) using random amplified polymorphic DNA (RAPD). Fifteen brinjal germplasm and three decamer primers were used for random polymorphic DNA assay. A total of 17 fragments were obtained, out of which 12 (70.59%) were polymorphic. Each primer generated 4 to 8 amplified fragments with an average of 5.67 fragments per primer. The highest genetic distance (0.8873) and the lowest genetic identity (0.4118) were observed in Laffa (Elongated) versus Jessore L and Dharola combinations. The lowest genetic distance (0.1525) was observed in several cultivars. The unweighted pair-group method of arithmetic means (UPGMA) dendrogram was constructed from genetic distance and all brinjal cultivars were grouped into five clusters. The genetic diversity of brinjal cultivars reported in this study will be useful when planning future crosses amongst these cultivars