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Fifty-six native isolates collected in 12 farming districts of Trinidad and seven reference strains of Xanthomonas campestris pv. campestris were evaluated for resistance to copper in buffered (pH 7.0) and unbuffered (pH 5.6) nutrient agar media. All isolates and reference strains were pathogenic and elicited typical black rot symptoms on a susceptible variety of Brassica olearceae, ‘Copenhagen Market’. Thirty-four and thirty-three native isolates were highly resistant to copper (growth on ≥ 200 ppm copper) in buffered and unbuffered media, respectively; however, all the reference strains were highly susceptible to copper. The mean minimum inhibition concentration for the 56 native isolates was 224.6 ppm copper indicating that high levels of copper resistance are present in X. campestris pv. campestris in Trinidad. The association between growth of the 56 isolates and seven reference stains on buffered and unbuffered media was strong (Pearson’s and Spearman’s r = 0.93; P

Carica papaya L. (Linn) (Caricaceae) is traditionally used to treat various skin disorders, including wounds. It is widely used in developing countries as an effective and readily available treatment for various wounds, particularly burns. This study evaluated the wound-healing and antimicrobial activity of C. papaya seed extract. Ethanol extract of C. papaya seed (50 mg/kg/day) was evaluated for its wound-healing activity in Sprague-Dawley rats using excision wound model. Animals were randomly divided into four groups of six each (group 1 served as control, group 2 treated with papaya seed extract, group 3 treated with a standard drug mupirocin and papaya seed extract (1:1 ratio) and group 4 treated with a mupirocin ointment. Rate of wound contraction and hydroxyproline content were determined to assess the wound-healing activity of the seed extract. The group 2 animals showed a significant decrease in wound area of 89% over 13 days when compared with groups 1 (82%), 3 (86%) and 4 (84%) respectively. The hydroxyproline content was significantly higher with the granulation tissue obtained from group 2 animals which were treated with C. papaya seed extract. Histological analysis of granulation tissue of the group 2 animals showed the deposition of well-organized collagen. The extract exhibited antimicrobial activity against Salmonella choleraesuis and Staphylococcus aureus. Our results suggest that C. papaya promotes significant wound healing in rats and further evaluation for this activity in humans is suggested.

Iron (Fe) deposition from African dust has been implicated in a variety of environmental impacts on downwind terrestrial and marine ecosystems throughout the Caribbean. The most abundant form of Fe in African dust is FeIII, which is often not bioavailable. The objective of this study was to determine to what degree microorganisms isolated from African dust collected in Trinidad and Tobago are capable of producing siderophores that mobilize bioavailable Fe into the environment. Aerosol samples were collected for microbial analyses during African dust conditions in the source region (Mali) and downwind sites (Trinidad and Tobago). Microbial community fingerprints, obtained by means of terminal restriction fragment length polymorphism analysis, were compared among aerosol samples and possible Trinidadian sources of locally aerosolized microorganisms (sea water and soils). Ordination of the fingerprint data revealed similarities between aerosols from the source region and the aerosols and soils of downwind regions. Aerosol isolates from the downwind sites were screened for siderophore production using a modified chrome azurol-S (CAS) assay. Twenty-five percent of isolates tested that were sampled under non-dust conditions and 65% of African dust isolates produced at least one type of siderophore; among African dust isolates, all known classes of siderophores were produced. These data support African dust microorganism siderophore production as a viable mechanism by which Fe bioavailability may be increased in downwind locations, given appropriate conditions for microbial proliferation.

In Trinidad, Tilapia (Oreonchromis spp.) is one of the most important fresh water food fish and the number of farms has been increasing annually. A study was conducted in the local tilapia industry to determine the microbial quality of pond water, prevalence of bacterial pathogens and their anti-microbial resistance using the disk diffusion method. Seventy-five apparently healthy fish and 15 pond water samples from three of the four commercial tilapia fish farms in the country were processed. The 202 bacterial isolates recovered from fish slurry and 88 from water, belonged to 13 and 16 genera respectively. The predominant bacteria from fish slurry were Pseudomonas spp. (60.0%), Aeromonas spp. (44.0%), Plesiomonas (41.3%) and Chromobacterium (36.0%) (P0.05; chi(2)) compared with isolates from pond water where Bacillus spp. (80.0%), Staphylococcus spp., Alcaligenes spp. and Aeromonas spp. (60.0%) were most prevalent (P0.05; chi(2)). Using eight anti-microbial agents, to test bacteria from five genera (Aeromonas, Chromobacterium, Enterobacter, Plesiomonas and Pseudomonas), 168 (97.1%) of 173 bacterial isolates from fish slurry exhibited resistance to one or more anti-microbial agents compared with 47 (90.4%) of 52 from water (P0.05; chi(2)). Resistance was high to ampicillin, 90.2% (158 of 173), erythromycin, 66.5% (115 of 173) and oxytetracycline, 52.6%, (91 of 173) but relatively low to chloramphenicol, 9.8% (17 of 173) and sulphamethoxazole/trimethoprim, 6.4% (11 of 173) (P0.05; chi(2)). For pond water isolates, the frequency of resistance across bacterial genera ranged from 75% (nine of 12) for Chromobacter spp. to 100% found amongst Enterobacter spp. (six of six), Plesiomonas spp. (nine of nine) and Pseudomonas spp. (eight of eight) (P0.05; chi(2)). Resistance was generally high to ampicillin, 78.8% (41 of 52), erythromycin, 51.9% (27 of 52) and oxytetracycline, 34.5% (18 of 52) but low to sulphamethoxazole/trimethoprim, 7.7% (four of 52) and norfloxacin, 3.8% (two of 52) (P0.05; chi(2)). It was concluded that the rather high prevalence of bacterial pathogens in tilapia along with their high prevalence of resistance to anti-microbial agents might pose therapeutic problems as well as health risk to consumers. The microbial presence and their anti-microbial resistance in the tilapia industry are being reported for the first time in the country.

A total of 480 samples of locally produced processed meats, including chicken franks, chicken bologna, and bacon from brands A and B, was collected from 8 supermarkets across the island of Trinidad over a 1-year period and subjected to a range of microbiological analyses. The results showed that 54.2, 0.4, and 1.7% of the samples exceeded recommended limits for aerobic bacteria, Escherichia coli and Staphylococcus aureus, respectively. Listeria spp. were detected in 19.4% of samples, whereas L. monocytogenes was present at a prevalence rate of 7.5%. Brand A products had lower microbiological quality, accounting for 100% of samples positive for L. monocytogenes, E. coli, and S. aureus; and 75% for Listeria spp. and coliforms. Bacon was the product that most frequently exceeded microbiological limits, and accounted for 100% of samples positive for E. coli, 83.3% for L. monocytogenes, 72% for Listeria spp., 62.5% for S. aureus, and 61.9% for coliforms.

Objectives of this study were to determine the burden and impact of acute gastroenteritis (AGE) and foodborne pathogens in Trinidad and Tobago. A retrospective, cross-sectional population survey, based on self-reported cases of AGE, was conducted in November-December 2008 and May-June 2009 (high- and low-AGE season respectively) by face-to-face interviews. From 2,145 households selected to be interviewed, the response rate was 99.9%. Of those interviewed, 5.1% (n = 110; 95% CI 4.3-6.2) reported having AGE (3 or more loose watery stools in 24 hours) in the 28 days prior to the interview (0.67 episodes/person-year). Monthly prevalence of AGE was the highest among children aged5 years (1.3 episodes/year). Eighteen (16%) persons with AGE sought medical care (4 treated with oral rehydration salts and 6 with antibiotics), and 66% reported restricted activity [range 1-16 day(s)]. The mean duration of diarrhoea was 2.3 days (range 2-10 days). One case submitted a stool sample, and another was hospitalized. Overall, 56 (10%) AGE specimens tested positive for foodbome pathogens. It was estimated that 135,820 AGE cases occurred in 2009 (84% underreporting), and for every 1 AGE case reported, an additional 6.17 cases occurred in the community. The estimated economic cost of AGE ranged from US$ 27,331 to 19,736,344. Acute gastroenteritis, thus, poses a huge health and economic burden on Trinidad and Tobago.

Background: Scombroid poisoning is responsible for the highest morbidity worldwide of any fish related food poisoning. However, there is little information available on this potential hazard to the fish consuming population of the Caribbean. This study focused on quantifying the levels of scombroid toxin (histamine) and selected histamine producing bacteria in two popularly consumed marine fish (carite, Scomberomorus brasiliensis and king fish, Scomberomorus cavalla ) in Trinidad, West Indies. Methods: A total of 78 fish were sampled at five different market types throughout the island. A commercial histamine kit was used to quantify histamine levels and the overall microbiological quality was evaluated from aerobic plate counts of fish tissue. Secondly, the role of fish and market types was investigated as potential sources of histamine producing bacteria (HPB). Results and conclusion: Of the fish sampled, 98.7% had histamine levels within USFDA acceptable limits of ≤ 50ppm. Overall, histamine levels were significantly higher in carite than in kingfish. One carite sampled from a wholesale market was in violation of the limit with a histamine level of 57 ppm. A significant relationship was observed between sensory characteristics and histamine levels. Fish tissue and gills were the main sources of histamine producing bacteria. There was a significant (p = 0.05) association between market type and the number of histamine producing bacterial types, with the highest morphological diversity of HPB present in fish from landing sites and retail markets. These market types also had the highest proportion of bacterial isolates positive for potential histamine production (12.9% each) as compared to supermarkets (11.3%), wholesale markets (8.1%) and mongers (6.5%).

SUMMARYContamination of locally produced, ready-to-eat meats byListeriaspp. has been previously reported at one processing plant in Trinidad. However, the status of this pathogen in locally produced products sold at retail outlets is unknown. This study was conducted to establish whether there is a risk to consumers of locally processed meats caused by the presence ofListeriaspp., and whether a link exists between the presence of the pathogen in retail products and the manufacturing plant of one brand (B). Four hundred and eighty ready-to-eat meat products of two popular local brands (A and B) were collected from retail outlets and analysed for the presence ofListeriaspp. together with food samples and surfaces from one manufacturing plant (B). Eighty-eight of the retail products (18·3%) were contaminated withListeriaspp., of which, 52·3% wereL. innocua, 44·3% wereL. monocytogenesand 3·4% belonged to theL. seeligeri–L. welshimeri–L. ivanovii(Siwi) group.L. innocuawas found in 15 in-process food samples and on three surfaces of equipment at plant B. Four in-process food samples were also contaminated with Siwi isolates. Repetitive extragenic palindromic PCR DNA fingerprinting showed a possible association between strains of differentListeriaspp. and brand as well as with manufacturing plant B.

A study was conducted to determine the possible influence of recreation on microbiological water quality of a tropical stream. Microbiological water quality was measured at several recreational sites along the stream and a separate experiment was conducted to look at the effect of sediment resuspension on microbiological water quality. Microbiological quality of the water in the stream was generally poor and varied widely with faecal coliform and Escherichia coli levels ranging from 1 to16,000 and 14 to 9615 organisms 100 ml(-1) respectively. Levels of faecal coliforms were higher in the wet (median = 700 organisms 100 ml(-1)) than the dry (median = 500 organisms 100 ml(-1)) season while the reverse was true for E. coli (median = 300 and 220 organisms 100 ml(-1) in the wet and dry seasons respectively). Recreational activity resulted in reduced water quality: sites with recreation had poorer water quality than those without; water quality was generally poorer when there were high numbers of recreational users. Wading resulted in a 4-fold increase in mean E. coli densities and a 3-fold increase in total suspended sediments in the overlying water suggesting that the increases were due to suspension of bacteria from the sediments. We conclude that water quality monitoring methodology for assessing recreational water quality should be amended to factor in the effects of wading since environmental strains of bacteria can be pathogenic and thus represent a human health threat.

Lantana camara is used in herbal medicine for the treatment of skin itches, as an antiseptic for wounds, and externally for leprosy and scabies. The objective of our study was to investigate excision wound healing activity of the leaf extract of L. camara in rats. The animals were divided into two groups of 12 each in both the models. The test group animals were treated with the aqueous extract of L. camara (100 mg/kg/day) topically and the control group animals were left untreated. Wound healing efficacy was measured by determining the morphological and biochemical parameters. Wound healing time, wound contraction and synthesis of collagen were monitored periodically. Antimicrobial activities of the extract against the microorganisms were also assessed. Treatment of the wounds with extract enhanced significantly the rate of wound contraction (98%), synthesis of collagen and decreased mean wound healing time. These studies demonstrate that L. camara is effective in healing excision wounds in the experimental animal and could be evaluated as a therapeutic agent in tissue repair processes associated with skin injuries.

An investigation was carried out to determine the diversity of 30 isolates of slow growing pigeonpea nodulating rhizobia based on variations in partial sequences of the 16S rRNA gene and numerical analysis of 80 phenotypic traits. Phylogenetic analysis using molecular sequences of 23 isolates showed that ARPE1 separated from the other isolates at an average distance of >14% divergence level. The other isolates were all within 5% divergence from each other but separated into four main groups, with group 1 containing 16 of the 23 isolates. Comparisons to sequences of reference strains revealed that the group 1 isolates were phylogenetically closely related to the slow growing soybean nodulating rhizobia belonging to Bradyrhizobium elkanii, although only three of these isolates were able to nodulate soybean. Numerical analysis of phenotypic data of 19 isolates showed that 14 isolates clustered together in one branch of the phenogram, which included the group 1, group 2 and group 4 isolates from the phylogenetic analysis. The group 3 isolates were highly variable in the phenogram with similarity levels lower than 50% among these isolates.