Molecular characterization of mycotoxin-producing Aspergillus parasiticus and sensitivity pattern to different disinfectants

Aims@#The study was aimed to isolate and characterize the mycotoxin-producing filamentous Aspergillus parasiticus from the feed samples. The sensitivity pattern of the isolates was assessed against different disinfectants.@*Methodology and results@#Fifty different feed samples were screened for A. parasiticus isolation. Isolates were subjected to macroscopic and microscopic characterization. Polymerase chain reaction was performed to confirm the isolates at the genomic level. Mycotoxin producing potential of the isolates was assessed by thin-layer chromatography (TLC). To quantify the toxins, high performance liquid (HPLC) was employed. The antifungal potential of disinfectants was determined by the well diffusion method followed by minimum inhibitory concentration (MIC) calculation. Out of twenty isolates of A. parasiticus, 11(55%) isolates were observed positive for toxin production. Three toxigenic isolates (AspP2, AspP4 and AspP8) were selected to evaluate their susceptibility against disinfectants by well diffusion method. AspP2 produced maximum (5.90 ng/mL) toxin, followed by AspP4 (3.11 ng/mL) and AspP8 (18.47 ng/mL). Terralin showed maximum fungicidal activity with 29.66 ± 8.08 mm zone of inhibition at 0.42 μg/mL MIC. Hypochlorite and Instru Star showed 99% disinfection with 30, 60 and 90 min contact time (6 mean log reduction) for all A. parasiticus isolates. Alpha Guard inhibited growth after 15 min contact time for all the isolates.@*Conclusion, significance and impact of study@#This study provides data indicating the contamination of feed samples with mycotoxin-producing A. parasiticus isolates and their sensitivity against commercially available disinfectants. Use of these disinfectants in appropriate concentrations and time could help prevent the contamination of food, feed and healthcare settings with the fungal species.

Biofuel production potential of indigenous isolates of Scenedesmus sp. from lake water in Pakistan

Aims@#This paper presents the report on biodiesel and biogas production at a laboratory scale from Scenedesmus strain.@*Methodology and results@#Previously isolated and identified Scenedesmus were grown in 10 Liter flask using BG-11 media at 16 h light and 8 h dark cycle. Oven-dried biomass (20 g) from 16-day-old culture of Scenedesmus was finely grounded and subjected to lipids extraction by chloroform-methanol-NaCl mixture. Microalgal lipids (6 mL) were subjected to transesterification by using NaOH leading to the production of 5 mL biodiesel and 4 mL of glycerin. Biodiesel was rich in methyl esters of linoleic acid, phosphorothioc acid and dodecanoic acid, as shown by gas chromatography-mass spectrometry (GC-MS) analysis. Oven-dried microalgae (2 g) without lipid extraction and leftover biomass (2 g) after lipid extraction were subject to biogas production through anaerobic digestion. Biogas (34, 27 and 19 mL) were recorded respectively in oven-dried whole biomass; lipid extracted biomass and control over a period of 15 days of anaerobic digestion.@*Conclusion, significance and impact of study@#It was concluded that water bodies are rich in diverse algae, especially Scenedesmus sp., and this algae can be cultured to produce biodiesel and biogas. But the lipid accumulation potential of microalgae requires special treatment and lipid extraction methods are not up to the mark, which is a major bottleneck in biofuel production from microalgae.

Isolation and antibiotic susceptibility of E. coli from urinary tract infections in a tertiary care hospital

The study was conducted to isolate and determine the antibiotic resistance in E. coli from urinary tract infections in a tertiary care hospital, Lahore. Urine samples [n=500] were collected from patients with signs and symptoms of Urinary tract infections. Bacteria were isolated and identified by conventional biochemical profile. Antibiotic resistance pattern of E. coli against different antibiotic was determined by Kirby-Baur method. Bacterial etiological agent was isolated from 402 samples with highest prevalence of E. coli [321, 80%] followed by Staphylococcus aureus [9.4%], Proteus species [5.4%] and Pseudomonas species [5.2%]. The E. coli were highly resistant to penicillin [100%], amoxicillin [100%] and cefotaxime [89.7%], followed by intermediate level of resistance to ceftazidime [73.8%], cephradine [73.8%], tetracycline [69.4%], doxycycline [66.6%], augmentin [62.6%], gentamycin [59.8%], cefuroxime [58.2%], ciprofloxacin [54.2%], cefaclor [50%], aztreonam [44.8%], ceftriaxone [43.3%], imipenem [43.3%], and low level of resistance to streptomycin [30%], kanamycin [19.9%], tazocin [14%], amikacin [12.7%] and lowest to norfloxacin [11.2%]. Out of 321 E. coli isolates, 261 [81%] were declared as multiple drug resistant and 5 [1.5%] were extensive drug resistant. It is concluded that most of the urinary tract infections in human are caused by multiple drug resistant E. coli