METHODS: Different combinations of nitrogen sources, salts and pre-culture combinations were applied in the fermentation media and lovastatin yield was analysed chromatographically.
RESULT: The exclusion of MnSO4 ·5H2O, CuSO4·5H2O and FeCl3·6H2O were shown to significantly improve lovastatin production (282%), while KH2PO4, MgSO4·7H2O, and NaCl and ZnSO4·7H2O were indispensable for good lovastatin production. Simple nitrogen source (ammonia) was unfavourable for morphology, growth and lovastatin production. In contrast, yeast extract (complex nitrogen source) produced the highest lovastatin yield (25.52 mg/L), while powdered soybean favoured the production of co-metabolites ((+)-geodin and sulochrin). Intermediate lactose: yeast extract (5:4) ratio produced the optimal lovastatin yield (12.33 mg/L) during pre-culture, while high (5:2) or low (5:6) lactose to yeast extract ratio produced significantly lower lovastatin yield (7.98 mg/L and 9.12 mg/L, respectively). High spore concentration, up to 107 spores/L was shown to be beneficial for lovastatin, but not for co-metabolite production, while higher spore age was shown to be beneficial for all of its metabolites.
CONCLUSION: The findings from these investigations could be used for future cultivation of A. terreus in the production of desired metabolites.
Methods: A cross-sectional study was conducted from March to July 2019 on 126 students and 37 laboratory staff/clinical instructors' MPs from the Faculty of Health Sciences, Universiti Teknologi MARA, Malaysia by a simple random sampling technique. Along with the questionnaire, a swab sample from each participant's MPs was collected and transported to the microbiology laboratory for bacterial culture as per standard microbiological procedures and antimicrobial susceptibility test by the disc diffusion technique. Data were analysed by the Statistical Package for Social Sciences Programme version 24.
Results: All of the tested MPs were contaminated with either single or mix bacterial agents. Bacillus spp. (74.8%), coagulase-negative staphylococci (CoNS; 47.9%) and S. aureus (20.9%) were the most predominant bacterial isolates, whilst the least isolate was Proteus vulgaris (P. vulgaris) (2.5%). Oxacillin resistance was seen in 5.9% of S. aureus isolate. A comparison of bacteria type and frequency among gender showed a significant difference with P. vulgaris (P = 0.003) and among profession showed a significant difference with S. aureus (P = 0.004).
Conclusion: The present study indicates that MPs can serve as a vector for both pathogenic and non-pathogenic organisms. Therefore, full guidelines about restricting the use of MPs in laboratory environments, hand hygiene and frequent decontamination of MPs are recommended to limit the risk of cross-contamination and healthcare-associated infections caused by MPs.
Methods: A prospective, observational single-centre study was conducted where all 504 cases that were consecutively admitted for pneumonia were enrolled. Blood and sputum samples obtained were used to identify pathogens using standard microbiological culture methods. The urine samples collected were tested using the ImmunocatchTMLegionella immunochromatographic (ICT) urine antigen test.
Results: A microbiological diagnosis was only achieved in 104 cases (20.6%) and a Gram-negative infection predominance was observed. Culture-positive cases required longer hospitalisation (8.46 days versus 5.53 days; P < 0.001) and the higher usage of antipseudomonal antibiotics (23.1% versus 8.3%; P < 0.001). Only 3 cases (0.6%) were diagnosed with Legionella pneumonia.
Conclusion: The local pathogen distribution is diverse compared to other regions. Culture-negative pneumonia is common and significantly differs from culture-positive pneumonia. Legionella pneumophila serotype 1 is not a common cause of pneumonia and LUAT did not help demystify the cause of culture-negative pneumonia.
OBJECTIVE: This study investigated the occurrence of C. nivariensis and C. bracarensis in a culture collection of 185 C. glabrata isolates at a Malaysian teaching hospital.
METHODS: C. nivariensis was discriminated from C. glabrata using a PCR assay as described by Enache-Angoulvant et al. (J Clin Microbiol 49:3375-9, 2011). The identity of the isolates was confirmed by sequence analysis of the D1D2 domain and internal transcribed spacer region of the yeasts. The isolates were cultured on Chromogenic CHROMagar Candida (®) agar (Difco, USA), and their biochemical and enzymic profiles were determined. Antifungal susceptibilities of the isolates against amphotericin B, fluconazole, voriconazole and caspofungin were determined using E tests. Clotrimazole MICs were determined using a microbroth dilution method.
RESULTS: There was a low prevalence (1.1 %) of C. nivariensis in our culture collection of C. glabrata. C. nivariensis was isolated from a blood culture and vaginal swab of two patients. C. nivariensis grew as white colonies on Chromogenic agar and demonstrated few positive reactions using biochemical tests. Enzymatic profiles of the C. nivariensis isolates were similar to that of C. glabrata. The isolates were susceptible to amphotericin B, fluconazole, voriconazole and caspofungin. Clotrimazole resistance is suspected in one isolate.
CONCLUSION: This study reports for the first time the emergence of C. nivariensis in our clinical setting.
RESULTS: Different production media were tested for lipase production by a newly isolated thermophilic Geobacillus sp. strain ARM (DSM 21496 = NCIMB 41583). The maximum production was obtained in the presence of peptone and yeast extract as organic nitrogen sources, olive oil as carbon source and lipase production inducer, sodium and calcium as metal ions, and gum arabic as emulsifier and lipase production inducer. The best models for optimization of culture parameters were achieved by multilayer full feedforward incremental back propagation network and modified response surface model using backward elimination, where the optimum condition was: growth temperature (52.3 degrees C), medium volume (50 ml), inoculum size (1%), agitation rate (static condition), incubation period (24 h) and initial pH (5.8). The experimental lipase activity was 0.47 Uml(-1) at optimum condition (4.7-fold increase), which compared well to the maximum predicted values by ANN (0.47 Uml(-1)) and RSM (0.476 Uml(-1)), whereas R2 and AAD were determined as 0.989 and 0.059% for ANN, and 0.95 and 0.078% for RSM respectively.
CONCLUSION: Lipase production is the result of a synergistic combination of effective parameters interactions. These parameters are in equilibrium and the change of one parameter can be compensated by changes of other parameters to give the same results. Though both RSM and ANN models provided good quality predictions in this study, yet the ANN showed a clear superiority over RSM for both data fitting and estimation capabilities. On the other hand, ANN has the disadvantage of requiring large amounts of training data in comparison with RSM. This problem was solved by using statistical experimental design, to reduce the number of experiments.