This study aimed to investigate antibiotic resistance and putative virulence factors among Cronobacter sakazakii isolated from powdered infant formula and other sources. The following 9 cultures (CR1-9) were collected from our culture collection: C. sakazakii and 3 Cronobacter species: C. sakazakii ATCC® 29544™, C. muytjensii ATCC® 51329™, C. turicensis E866 were used in this study. Isolates were subjected to antibiotic susceptibility and the following virulence factors (protease, DNase, haemolysin, gelatinase, motility and biofilm formation) using phenotypic methods. All the bacteria were able to form biofilm on agar at 37 °C and were resistant to ampicillin, erythromycin, fosfomycin and sulphamethoxazole. It was observed from this study that tested strains formed weak and strong biofilm with violet dry and rough (rdar), brown dry and rough (bdar), red mucoid and smooth (rmas) colony morphotypes on Congo red agar. Rdar expresses curli and fimbriae, while bdar expresses curli. Both biofilm colony morphotypes are commonly found in Enterobacteriaceae including Salmonella species. This study also reveals a new colony morphotypes in Cronobacter species. Conclusively, there was correlation between putative virulence factors and antibiotic resistance among the tested bacteria. Further study on virulence and antibiotic resistance genes is hereby encouraged.
This study aimed to compare population dynamics, antibiotic resistance and biofilm formation of Aeromonas and Vibrio species from seawater and sediment collected from Northern Malaysia. Isolates with different colony morphology were characterized using both biochemical and molecular methods before testing for antibiotic resistance and biofilm formation. Results obtained from this study showed that in Kedah, the population of Aeromonas isolated from sediment was highest in Pantai Merdeka (8.22 log CFU/ml), Pulau Bunting recorded the highest population of Aeromonas from sediment (8.43 log CFU/g). It was observed that Vibrio species isolated from seawater and sediment were highest in Kuala Sanglang (9.21 log CFU/ml). In Kuala Perlis, the population of Aeromonas isolated from seawater was highest in Jeti (7.94 log CFU/ml). Highest population of Aeromonas from sediment was recorded in Kampong Tanah Baru (7.99 log CFU/g). It was observed that Vibrio species isolated from seawater was highest in Padang Benta (8.42 log CFU/g) while Jeti Kuala Perlis had highest population of Vibrio isolated from sediment. It was observed that location does not influence population of Aeromonas. The results of the independent t - test revealed that there was no significant relationship between location and population of Vibrio (df = 10, t = 1.144, p > 0.05). The occurrence of biofilm formation and prevalence of antibiotic resistant Aeromonas and Vibrio species in seawater and sediment pose danger to human and aquatic animals' health.
This study aimed to investigate antibiotics resistance pattern and phenotyping of Aeromonas species isolated from different aquatic sources in Melaka, Malaysia. A total of 53 Aeromonas species were isolated from the following sources: sediment (n = 13), bivalve (n = 10), sea cucumber (n = 16) and sea water (n = 14) and resistance to 12 antibiotics - Tetracycline (30 μg), Kanamycin (30 μg), Oxytetracycline (30 μg), Ampicillin (10 μg), Streptomycin (10 μg), Gentamicin (10 μg), Sulphamethoxazole (25 μg), Nalixidic acid (30 μg), Trimethoprim (1.25 μg), Novobiocin (5 μg), Penicilin (10 μg) and Chloramphenicol (10 μg) was tested. The results obtained from this study reveal multi drug resistance pattern among the isolates. All the isolates were completely resistant to Ampicillin, Novobiocin, Sulphamethoxazole and Trimethoprim, respectively but susceptible to Tetracycline (100%), Kanamycin (5.7%), Gentamicin (5.7%) and Oxytetracycline (24.5%). Antibiotics phenotyping of the bacteria revealed 21 different phenotypes among the isolates.
Cronobacter species are motile, non-spore forming, Gram negative emerging opportunistic pathogens mostly associated with bacteremia, meningitis, septicemia, brain abscesses and necrotizing enterocolitis in infected neonates, infants and immunocompromised adults. Members of the genus Cronobacter are previously associated with powdered infant formula although the main reservoir and routes of contamination are yet to be ascertained. This study therefore aim to summarize occurrence and prevalence of Cronobacter spp. from different food related sources. A retrospective systematic review and meta-analysis of peer reviewed primary studies reported between 2008 and 2014 for the occurrence and prevalence of Cronobacter spp. in animal and plant related sources was conducted using "Cronobacter isolation", "Cronobacter detection" and "Cronobacter enumeration" as search terms in the following databases: Web of Science (Science Direct) and ProQuest. Data extracted from the primary studies were then analyzed with meta-analysis techniques for effect rate and fixed effects was used to explore heterogeneity between the sources. Publication bias was evaluated using funnel plot. A total of 916 articles were retrieved from the data bases of which 28 articles met inclusion criteria. Cronobacter spp. could only be isolated from 103 (5.7 %) samples of animal related food while 123 (19 %) samples of plant related food samples harbors the bacteria. The result of this study shows that occurrence of Cronobacter was more prevalent in plant related sources with overall prevalence rate of 20.1 % (95 % CI 0.168-0.238) than animal originated sources with overall prevalence rate of 8 % (95 % CI 0.066-0.096). High heterogeneity (I (2) = 84) was observed mostly in plant related sources such as herbs, spices and vegetables compared to animal related sources (I (2) = 82). It could be observed from this study that plant related sources serve as reservoir and contamination routes of Cronobacter spp.
The objective of this study was to examine the frequency and extent of antibiotic-resistant pathogens in seafood sold in Malaysia, using a systematic review and meta-analysis approach to analyze primary research studies. Four bibliographic databases were systematically searched for primary studies on occurrence. Meta-analysis using a random-effect model was used to understand the prevalence of antibiotic-resistant bacteria in retail seafood sold in Malaysia. A total of 1938 primary studies were initially identified, among which 13 met the inclusion criteria. In the included primary studies, a total of 2281 seafoods were analyzed for the presence of antibiotic-resistant seafood-borne pathogens. It was observed that 51% (1168/2281) of the seafood was contaminated with pathogens. Overall, the prevalence of antibiotic-resistant seafood-borne pathogens in retail seafood was 55.7% (95% CI: 0.46-0.65). Antibiotic-resistant Salmonella species had an overall prevalence of 59.9% (95% CI: 0.32-0.82) in fish, Vibrio species had an overall prevalence of 67.2% (95% CI: 0.22-0.94) in cephalopods, and MRSA had an overall prevalence of 70.9% (95% CI: 0.36-0.92) in mollusks. It could be concluded that there is a high prevalence of antibiotic-resistant seafood-borne pathogens in the retail seafood sold in Malaysia, which could be of public health importance. Therefore, there is a need for proactive steps to be taken by all stakeholders to reduce the widespread transmission of antibiotic-resistant pathogens from seafood to humans.
Biofloc Technology (BFT) is proven to be the fulcrum of sustainable recirculating aquaculture system especially under zero water discharge condition. The efficiency of BFT system is reinforced by an unswerving microbial community in the system. Several researchers have made copious reports on the microorganisms in BFT and identified heterotrophic bacteria predominant in the microbial composition. A summary of these researches considers these microorganisms playing the role of chemo-photosynthetic autotrophs, organic detoxifiers, probiotic, decomposers/bioflocculants, bio-leachers and pathogens. Although these functional roles are well identified, the reports have failed to sufficiently illustrate the borderline at which these microbial communities fail to serve their beneficial roles in BFT system. This review paper firstly presents a snapshot of some indispensable water quality conditions and zootechnical variables aided by the microbial community in floc as well as the amphibolic process that synthesizes nutrient from the organic deposit in BFT. Furthermore, information on the microbial community in BFT is evaluated to have Bacillus sp., Lecane sp. and Pseudomonas sp. serving all-encompassing role in BFT while Vibrio sp. and Enterobacter sp. are pathogenic under unsuitable water quality conditions. Functional characterisation of the commonly reported microorganisms in BFT categorised 21.95 % as most critical, whose abundance indicates an efficient BFT.
An international survey among consumers in developing countries from Asia and Africa on food safety knowledge, attitudes and practices (KAP) was carried out using structured questionnaires. Data were collected from 453 consumers comprising 265 from Africa and 188 from Asia. Significant difference (p