Incidence, Antibiotic Susceptibility and Characterization of Vibrio parahaemolyticus Isolated from Seafood in Selangor, Malaysia

Vibrio parahaemolyticus is one of the major foodborne pathogens owing to its cause of infectious diseases such as gastroenteritis. These diseases are often associated with the consumption of contaminated seafood. This study aims to investigate the presence of V. parahaemolyticus, their virulence, antibiotic profiles, and plasmid profiles from 77 different kinds of shellfish samples collected from wet markets and supermarkets in Selangor, Malaysia. High densities of Vibrio species ( > 5 log CFU/g) were found in 14/16 groups of shellfish. Among 77 presumptive V. parahaemolyticus isolates, 43 (55.8%) were positive for the toxR gene, confirming the identity of the isolates at the species level. However, none of the V. parahaemolyticus isolates harboured the virulence tdh and trh genes. The antibiotic susceptibility of the V. parahaemolyticus isolates revealed that most of them were resistant to ampicillin (95.3%), ampicillin-sulbactam (81.4%), cefotaxime (37.2%) and imipenem (23.3%). The plasmid profiles of the V. parahaemolyticus isolates showed that 41.9% (18/43) possess at least one plasmid. Our results indicate the V. parahaemolyticus isolates are continuously exposed to various antibiotics in the environments, thus consuming the seafood carries a potential health risk to consumers. The antibiotic resistance conferred by the species necessitates an immediate plan to approach the usage of antibiotics differently.

Plasmid Profiling and Effect of Different Physiological Parameters on the Chromium Reduction Potential of Microbes

Chromium is toxic for both human and aquatic life. It is recommended to eradicate from wastewaters or to alter its oxidation state to less toxic level The purpose of current research was to isolate heavy metal (Cr) resistant bacteria from different industrial effluents (soil and waste water), to determine their potential for chromium reduction (CRP) at different parameters (time period, pH, temperature and concentrations of chromium) and to determine the plasmid profiles of Cr (VI) resistant bacterial isolates. The growth of chromium resistant bacteria was determined by checking the influence of pH, concentration of chromium, time period and temperature on isolates using UV spectrophotometer, while chromium reduction potential was also investigated using Deleo and Ehrlich method. Plasmid profiling was performed and analyzed using agarose gel electrophoresis (0.8%) to determine the number, size and relationship of plasmid with heavy metal resistance. Results showed that the identified bacterial isolates (S. aureus and S. epidermidis) were resistant to heavy metal (Cr) confirmed by resistance profiling. The maximum growth of bacterial isolate was recorded after 24-hour incubation period (1.154), at pH 8 (1.512), temperature 37ºC (1.615) and 500 µg/mL chromium concentration (1.978), while suitable conditions observed for chromium reduction potential was 24-hour incubation period (57%), pH 7 (62.6%), temperature 30ºC (60%), and 500 µg/mL concentration of chromium (60%). The plasmid profiles revealed that plasmid were randomly distributed among the bacterial isolates with average plasmid number (2.9) ranging from 0-5 and molecular size (100-12000bps). Overall, no defined relationship was observed among resistance pattern and plasmid mediated profiles.

Antimicrobial Resistance Patterns and Plasmid Profiles of Methicillin Resistant Staphylococcus aureus Isolated from Clinical Samples

Methicillin-resistant Staphylococcus aureus (MRSA), showing resistance to several antibiotics is a global health problem associated with considerable mortality and morbidity. Antibiotic susceptibility test is a commonly used method to characterize MRSA in epidemiologic studies. Additionally, plasmid profile has been reported to be useful in tracing the epidemiology of antibiotic resistance. This research was conducted to determine the antimicrobial resistance patterns and plasmid profiles of MRSA isolated from clinical samples at KIST Medical College, Imadol, Kathmandu, Nepal. All the clinical specimens sent to the laboratory were processed by standard microbiological techniques and antibiotic susceptibility testing was done by the modified Kirby Bauer disc diffusion method. Further, plasmid profiling was done by Alkaline-lysis method. A total of 27 (38.02%) MRSA were isolated from 71 S. aureus positive samples. MRSA showed the highest resistance towards penicillin (92.60%) and ampicillin (92.60%). In contrast, high levels of sensitivity were shown towards vancomycin (85.19%) and tetracycline (85.19%). Out of 27 MRSA positive samples, single plasmids were isolated from only 6 (22.22%) MRSA isolates. Antibiograms alone are inadequate to accomplish the characterization of MRSA during epidemiological studies. However, plasmid profile analysis in conjunction with the antibiotic susceptibility pattern is valuable in the epidemiological investigation of MRSA, and for reducing MRSA prevalence and treatment cost.

Plasmid Profiles of Pseudomonas syringae pv. savastanoi.

Pseudomonas syringae pv. savastanoi (Psv) is the causal agent of olive knot disease. Forty nine bacterial isolates of Psv were isolated from knots on several hosts at the western area of Libya: 31 isolates from olive Olea europaea, 17 isolates from athel Tamarix aphylla (on which the disease is documented for the first time) and one isolate from retem Retama raetam. The isolates were identified on the basis of their morphological characteristics and LOPAT profile. They produced round, white creamy colonies on selective media (PAB and KB), from which 15 isolates produced fluorescent pigments. With the exception of other LOPAT analysis, all isolates were pectinolytic activity and arginine dihydrolase negative. some isolates were levan positive (10 isolates) and oxidase positive (12 isolates), while the rest of isolates were negative for both tests. Most of the isolates induced a hypersensitive reaction on tobacco and pepper leaves. Plasmid profile analysis of Psv strains indicated high genetic variability between the isolates of the same host or different hosts. Most of the olive isolates were classified according to their plasmid profile into five groups (A, B, C, D, F), however, the athel isolates were separated into three different groups designated as G, K, N, on the other hand, group E and H contained mixed isolates from different hosts: group H included two isolates from olive (OS25w and OS42w) and one isolate from retem (Ra1); only two strains OS6w and Ta5y from olive and athel respectively were classified within the same group designated as E. The remaining seven isolates from all hosts were unique. The total number of plasmids ranged from 1-4 for the strains tested, while the DNA content varied widely ranging from 540 to 13550 bp. No plasmid were detected in 14 isolates tested. Genome analysis based on plasmid profiles indicated the great potential of this technique to discriminate between the isolates of Psv from different hosts and geographical regions.

Multiple Antibiotic Resistance (MAR), Plasmid Profiles, and DNA Polymorphisms among Vibrio vulnificus Isolates

Sixty strains (n = 60) of Vibrio vulnificus were examined for their multiple antibiotic resistance (MAR) index, plasmid profiles, and DNA polymorphisms. Thirty-seven strains (n = 37) were isolated from cockles (Anadara granosa) in Malaysia, while 23 (n = 23) isolates were isolated from clams (Mercenaria mercenaria) in Qatar. All isolates were resistant to two or more of the antibiotics tested, with the most common resistances were demonstrated towards penicillin (93%), ampicillin (70%), cephalothin (65%), clindamycin (66%), vancomycin (64%), and erythromycin (51%). The antibiotic that experienced the least resistance was kanamycin (6%), and all isolates were susceptible to cefoperazone, streptomycin, and tetracycline. The MAR index for the V. vulnificus isolated from Malaysia and Qatar, possessed similar values which ranged from 0.2 to 0.7, respectively. Plasmid analysis demonstrated that 65% of V. vulnificus strains harbored plasmids, while 35% were not. Nineteen (P1–P19) plasmids profiles were observed. No specific cluster or group was observed although they were isolated from different sample sources and locations by phylogenetic analysis using GelCompar II software at an 80% similarity level. Results demonstrated the high MAR index and genomic heterogeneity of V. vulnificus, which are of great concern to the human health of those who have consumed cockles and clams from the study area.