Occurrence of methicillin-resistant Staphylococcus aureus in pets and their owners in rural and urban communities in Trinidad.

INTRODUCTION: The occurrence of methicillin-resistant Staphylococcus aureus (MRSA) in pets and their owners has increased due to the misuse and abuse of antibiotics. This study compared the prevalence of MRSA and Staphylococcus aureus strains in pets and their owners in urban and rural communities in Trinidad. METHODOLOGY: Questionnaires were administered to gather demographic and risk factor data for MRSA for human participants, and their pets. Nasal swabs were obtained from 100 pets (dogs and cats) and their human owners. For the isolation of MRSA, nasal swabs obtained were enriched and then plated on selective media. Staphylococcus aureus was identified using standard biochemical procedures. The resistance of S. aureus initially assessed detection of MRSA isolates to cefoxitin and confirmed by the PBP2a latex agglutination test. Antibiotic resistance was determined using the disc diffusion method. RESULTS: The prevalence of MRSA was 6.0% (3/50) and 2.0% (1/50) in household pet animals and their owners, respectively in urban communities, while in rural communities, the prevalence was 6.0% (3/50) and 12.0% (6/50) respectively. The prevalence of S. aureus in pet owners was higher in the rural community (44.0%) compared to urban (30.0%). However, in pet animals, S. aureus was more frequently isolated from urban communities (78.0%) than rural ones (66.0%). Amongst the S. aureus isolates, 81.7% were resistant to one or more antimicrobial agents. CONCLUSIONS: This study has demonstrated that living in a rural community increased the odds of MRSA colonization.

Prevalence of methicillin resistant Staphylococcus aureus (MRSA) in pigs and workers at abattoirs in Trinidad and Tobago.

INTRODUCTION: Methicillin resistant Staphylococcus aureus (MRSA), a major cause of zoonotic infections, has emerged globally in livestock, particularly pigs. People with occupational contact with food producing animals are at high risk of colonization. The aim of this study was to determine the prevalence of MRSA in pigs and abattoir workers throughout Trinidad and Tobago as well as their resistance to other antimicrobial agents. METHODOLOGY: Nasal and skin behind the ear swabs from pigs and nasal swabs from humans were enriched in Mueller Hinton broth with 6.5% sodium chloride, followed by phenol red mannitol broth with 75 mg/L aztreonam and 5 mg/L ceftizoxime. The enriched sample was then plated on both CHROMagar MRSA and Brilliance MRSA. All incubation was at 37ºC for approximately 24 h. Suspect MRSA isolates were confirmed as MRSA using the Penicillin-Binding Protein (PBP2a) test kit and polymerase chain reaction (PCR) to detect the mecA gene. Resistance of the S. aureus and MRSA isolates to 16 antimicrobial agents was determined using the disc diffusion method. RESULTS: Of the 929 pigs and 44 humans sampled, MRSA strains were isolated at a frequency of 0.9% (8/929) and 2.3% (1/44) respectively. All isolates exhibited resistance to one or more of the 16 antimicrobial agents. CONCLUSIONS: The study demonstrated that pigs and workers at slaughter houses in Trinidad and Tobago harbour multidrug resistance S. aureus and MRSA. This is of public health significance as occupational exposure of humans can lead to an increased risk of infection and therapeutic failure.

Prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in broilers and workers at 'pluck shops' in Trinidad.

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) is a cause of zoonotic infections in many countries. People with occupational contact with food animal production are at risk of colonization. The aim of this study was to determine the prevalence of MRSA and their frequency of resistance to other antimicrobial agents from broilers and workers at the 'pluck shops' in Trinidad. For isolation of MRSA, choanal, cloacal and pharyngeal swabs taken from broilers and nasal swabs from humans were enriched then plated on CHROMagar MRSA and Brilliance MRSA. MRSA was confirmed using the PBP2a test kit, resistance to oxacillin and cefoxitin and polymerase chain reaction (PCR) for the mecA gene. Antimicrobial resistance of the MRSA isolates to 16 antimicrobial agents was determined using the disc diffusion method. Of the 287 broilers and 47 humans sampled, MRSA was isolated at a frequency of 2 (0.7%) and 0 (0.0%) respectively. All the MRSA isolates exhibited resistance to one or more of the 16 antimicrobial agents. The study demonstrated that broilers at 'pluck shops' in Trinidad harbor MRSA. This is the first isolation of MRSA from poultry in Trinidad, West Indies, and this finding is of public health significance since occupational exposure of humans can lead to increased risk of acquiring MRSA infections.

Resistance to antimicrobial agents among Salmonella isolates recovered from layer farms and eggs in the Caribbean region.

This investigation determined the frequency of resistance of 84 isolates of Salmonella comprising 14 serotypes recovered from layer farms in three Caribbean countries (Trinidad and Tobago, Grenada, and St. Lucia) to eight antimicrobial agents, using the disc diffusion method. Resistance among isolates of Salmonella was related to the country of recovery, type of sample, size of layer farms, and isolate serotype. Overall, all (100.0%) of the isolates exhibited resistance to one or more of seven antimicrobial agents tested, and all were susceptible to chloramphenicol. The resistance detected ranged from 11.9% to sulphamethoxazole-trimethoprim (SXT) to 100.0% to erythromycin. The difference was, however, not statistically significant (P = 0.23). Across countries, for types of samples that yielded Salmonella, significant differences in frequency of resistance were detected only to SXT (P = 0.002) in Trinidad and Tobago and to gentamycin (P = 0.027) in St. Lucia. For the three countries, the frequency of resistance to antimicrobial agents was significantly different for ampicillin (P = 0.001) and SXT (P = 0.032). A total of 83 (98.8%) of the 84 isolates exhibited 39 multidrug resistance patterns. Farm size significantly (P = 0.032) affected the frequency of resistance to kanamycin across the countries. Overall, among the 14 serotypes of Salmonella tested, significant (P < 0.05) differences in frequency of resistance were detected to kanamycin, ampicillin, and SXT. Results suggest that the relatively high frequency of resistance to six of the antimicrobial agents (erythromycin, streptomycin, gentamycin, kanamycin, ampicillin, and tetracycline) tested and the multidrug resistance detected may pose prophylactic and therapeutic concerns for chicken layer farms in the three countries studied.

Survey of Salmonella contamination in chicken layer farms in three Caribbean countries.

This study was conducted to investigate the demography, management, and production practices on layer chicken farms in Trinidad and Tobago, Grenada, and St. Lucia and the frequency of risk factors for Salmonella infection. The frequency of isolation of Salmonella from the layer farm environment, eggs, feeds, hatchery, and imported day-old chicks was determined using standard methods. Of the eight risk factors (farm size, age group of layers, source of day-old chicks, vaccination, sanitation practices, biosecurity measures, presence of pests, and previous disease outbreaks) for Salmonella infection investigated, farm size was the only risk factor significantly associated (P = 0.031) with the prevalence of Salmonella; 77.8% of large farms were positive for this pathogen compared with 33.3 and 26.1% of medium and small farms, respectively. The overall isolation rate of Salmonella from 35 layer farms was 40.0%. Salmonella was isolated at a significantly higher rate (P < 0.05) from farm environments than from the cloacae. Only in Trinidad and Tobago did feeds (6.5% of samples) and pooled egg contents (12.5% of samples) yield Salmonella; however, all egg samples from hotels, hatcheries, and airports in this country were negative. Salmonella Anatum, Salmonella group C, and Salmonella Kentucky were the predominant serotypes in Trinidad and Tobago, Grenada, and St. Lucia, respectively. Although Salmonella infections were found in layer birds sampled, table eggs appear to pose minimal risk to consumers. However, the detection of Salmonella -contaminated farm environments and feeds cannot be ignored. Only 2.9% of the isolates belonged to Salmonella Enteritidis, a finding that may reflect the impact of changes in farm management and poultry production in the region.

Frequency of resistance to methicillin and other antimicrobial agents among Staphylococcus aureus strains isolated from pigs and their human handlers in Trinidad.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) has emerged recently worldwide in production animals, particularly pigs and veal calves, which act as reservoirs for MRSA strains for human infection. The study determined the prevalence of MRSA and other resistant strains of S. aureus isolated from the anterior nares of pigs and human handlers on pig farms in Trinidad. METHODS: Isolation of S. aureus was done by concurrently inoculating Baird-Parker agar (BPA) and Chromagar MRSA (CHROM) with swab samples and isolates were identified using standard methods. Suspect MRSA isolates from Chromagar and BPA were subjected to confirmatory test using Oxoid PBP2 latex agglutination test. The disc diffusion method was used to determine resistance to antimicrobial agents. RESULTS: The frequency of isolation of MRSA was 2.1% (15 of 723) for pigs but 0.0% (0 of 72) for humans. Generally, for isolates of S. aureus from humans there was a high frequency of resistance compared with those from pigs, which had moderate resistance to the following antimicrobials: penicillin G (54.5%, 51.5%), ampicillin (59.1%, 49.5%), and streptomycin (59.1%, 37.1%), respectively. There was moderate resistance to tetracycline (36.4%, 41.2%) and gentamycin (27.2%, 23.7%) for human and pig S. aureus isolates, respectively, and low resistance to sulfamethoxazole-trimethoprim (4.5%, 6.2%) and norfloxacin (9.1%, 12.4%), respectively. The frequency of resistance to oxacillin by the disc method was 36.4 and 34.0% from S. aureus isolates from humans and pigs, respectively. Out of a total of 78 isolates of S. aureus from both human and pig sources that were resistant to oxacillin by the disc diffusion method, only 15 (19.2%) were confirmed as MRSA by the PBP'2 latex test kit. CONCLUSIONS: The detection of MRSA strains in pigs, albeit at a low frequency, coupled with a high frequency of resistance to commonly used antimicrobial agents in pig and humans could have zoonotic and therapeutic implications. Finally, the diagnostic limitation of using CHROMagar and testing for oxacillin resistance by the disc diffusion method alone to determine MRSA strains without performing confirmatory tests cannot be overemphasized because the possibility of overdiagnosis of MRSA infections cannot be ignored.

Bioaerosol sampling for airborne bacteria in a small animal veterinary teaching hospital.

BACKGROUND: Airborne microorganisms within the hospital environment can potentially cause infection in susceptible patients. The objectives of this study were to identify, quantify, and determine the nosocomial potential of common airborne microorganisms present within a small animal teaching hospital. METHODS: Bioaerosol sampling was done initially in all 11 rooms and, subsequently, weekly samples were taken from selected rooms over a 9-week period. Samples were collected twice (morning and afternoon) at each site on each sampling day. The rooms were divided into two groups: Group 1, in which morning sampling was post-cleaning and afternoon sampling was during activity, and Group 2, in which morning sampling was pre-cleaning and afternoon sampling was post-cleaning. The total aerobic bacterial plate counts per m(3) and bacterial identification were done using standard microbiological methods. RESULTS: A total of 14 bacterial genera were isolated with the most frequent being Micrococcus spp. followed by species of Corynebacterium, Bacillus, and Staphylococcus. There was a significant interaction between location and time for rooms in Group 1 (p=0.0028) but not in Group 2 (p>0.05). Microbial counts for rooms in Group 2 were significantly greater in the mornings than in the afternoon (p=0.0049). The microbial counts were also significantly different between some rooms (p=0.0333). CONCLUSION: The detection of significantly higher airborne microbial loads in different rooms at different times of the day suggests that the probability of acquiring nosocomial infections is higher at these times and locations.

Serological Evidence of Exposure to Leptospira spp. in Veterinary Students and Other University Students in Trinidad and Tobago.

The study compared the serological evidence of leptospirosis in 212 students in four schools (veterinary, dental, advanced nursing education and pharmacy) of the University of the West Indies (UWI), by testing for IgG immunoglobulins to Leptospira spp. using the enzyme-linked immunosorbent assay (ELISA) and the microscopic agglutination test (MAT). Overall, of 212 students tested by the ELISA, 12 (5.7%) and 31 (14.6%) were positive and borderline, respectively. Amongst the 113 veterinary students 11 (9.7%) and 19 (16.8%) were seropositive and borderline respectively compared with nonveterinary students with corresponding values of 1 (1.0%) and 12 (12.1%). The frequency of serological evidence of leptospirosis by the ELISA was statistically significantly (P < 0.05; χ(2)) higher in veterinary students, 26.5% (30 of 113) than in nonveterinary students, 13.1% (13 of 99). By the MAT, the seropositivity for leptospirosis was similar for veterinary students, 7.1% (8 of 113) and nonveterinary students, 7.1% (7 of 99). For veterinary students, the prevalent infecting serovar was Icterohaemorrhagiae Copenhageni while amongst nonveterinary students, the prevalent serovar was Australis Rachmati. Being a veterinary student was the only risk factor that was significantly associated with Leptospira infection indicating that veterinary students need to be cognizant and to practise preventive measures for leptospirosis.

Prevalence and characteristics of enteric pathogens detected in diarrhoeic and non-diarrhoeic foals in trinidad.

The study determined the relative importance of Escherichia coli, E. coli O157, Salmonella spp., Clostridium spp., rotavirus, Cryptosporidium spp., and Strongyloides westeri in foal (diarrhoeic and non-diarrhoeic) available for sampling during the foaling season of 2010 and determined their sensitivity to antimicrobial agents. A cross-sectional study was conducted on 164 foals (9 diarrhoeic and 155 non-diarrhoeic) from 15 farms in Trinidad. Isolation and detection of enteric pathogens followed standard methods, and the antibiograms of E. coli and Salmonella spp. were determined using the disc diffusion method. All organisms investigated were detected except E. coli O157. A high prevalence of E. coli (85.0%), Cryptosporidium spp. (64.8%), Strongyloides westeri (35.7%) was seen, but the prevalence was comparatively low for Clostridium spp. (12.9%), Salmonella spp. (4.4%) and rotavirus (2.1%). Only Salmonella spp. was isolated at a statistically significantly (P < 0.05; χ(2)) higher frequency from diarrhoeic (25.0%) than non-diarrhoeic (4.0%) foals. Amongst E. coli isolates, the frequency of resistance was higher in isolates from diarrhoeic compared with non-diarrhoeic foals but the difference was only statistically significant (P < 0.05; χ(2)) for tetracycline. All isolates of Salmonella spp. were sensitive to streptomycin and sulphamethoxazole/trimethoprim, a finding that may have therapeutic significance.

Serological evidence of hantavirus infection in farm and abattoir workers in Trinidad--a preliminary study.

Hantaviruses are established causative agents of hemorrhagic fevers and renal diseases amongst other clinical manifestations in humans, with most diagnosis based on serological assays. The disease, which is rodent-borne, has been reported in numerous countries worldwide but information about the disease is scanty in the Caribbean. The objective of this investigation is to determine the frequency of exposure to hantaviruses in a selected apparently healthy human population associated with abattoirs and livestock farms in Trinidad using a hantavirus immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA). Of a total of 236 individuals tested, 27 (11.4%) were seropositive for hantavirus infection. Amongst abattoir workers the frequency of infection was 9.4% (6 of 64) compared with seropositivity rate of 12.4% (18 of 145) and 11.1% (3 of 27) amongst livestock farm workers and office workers and other individuals with minimal animal contact respectively. The differences were, however, not statistically significant (p > .05; χ(2) test). Age, gender, and race did not significantly affect the infection rate by hantavirus in the workers studied. This is considered the first documented evidence of hantavirus infection in Trinidad and Tobago. It is imperative for local physicians to consider hantavirus as a differential diagnosis in patients with hemorrhagic fever and renal diseases, since there may be a number of undiagnosed cases of hantavirus disease in the human population in the country.

Frequency of detection of immunoglobulins of Toxoplasma gondii, Leptospira spp., and Brucella abortus in livestock/farm and abattoir workers in Trinidad.

Toxoplasma gondi, Leptospira spp., and Brucella abortus are all established parasitic and bacterial zoonoses that manifest themselves in several forms of human diseases. They have been associated with occupational exposures, particularly amongst workers associated with livestock farms. The primary objectives of this study were to determine the seroprevalence of T. gondii immunoglobulin M (IgM) immunoglobulins (serum antibodies), Leptospira IgM immunoglobulins, and B. abortus IgG immunoglobulins, suggestive of acute or chronic infections, in livestock/farm and abattoir workers in Trinidad, and to relate to risk factors. Blood samples were collected from 394 consenting livestock/farm workers and 99 abattoir workers across the island of Trinidad. Serological status was determined by enzyme immunoassay (EIA) for T. gondii IgM, enzyme-linked immunosorbent assay (ELISA) for Leptospira IgM immunoglobulins, and buffered plate agglutination test (BPAT) and competitive ELISA for B. abortus IgG immunoglobulins. Of 394 apparently healthy livestock/farm workers sampled, 150 (38.1%) were seropositive for T. gondii IgM immunoglobulins, compared with 44 (44.4%) of 99 abattoir workers (p > .05; χ(2) test). Five (1.3%) of 371 and 1 (1.0%) of 99 livestock/farm and abattoir workers respectively were positive for Leptospira IgM immunoglobulins. All samples from livestock/farm workers and abattoir workers were negative for B. abortus immunoglobulins. None of the risk factors investigated was statistically significantly (p > .05; χ(2) test) associated with T. gondii and Leptospira spp. infections.

Human leptospirosis in the Caribbean, 1997-2005: characteristics and serotyping of clinical samples from 14 countries.

OBJECTIVE: To determine the frequency of human leptospirosis in the sera of suspected clinical cases sent by 14 Caribbean countries for diagnosis to a regional laboratory in 1997-2005. METHODS: All serum samples were initially tested using the immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA) for leptospirosis. Demographic data (such as age and sex), month of the year and clinical manifestations that had been observed by the attending physician were related to seropositivity. The microscopic agglutination test (MAT) was used to serotype sera using a panel of 23 international serovars. RESULTS: Of 3 455 samples tested, 452 (13.1%) were seropositive for IgM antibodies to leptospirosis by the ELISA, with frequencies significantly (P < 0.05; χ2) different across countries and years. Among seropositive patients, the frequency of detection of leptospirosis (23.1%) was significantly higher in the age groups 1-20 years and 31-40 years combined compared with other age groups; and in male patients (72.1%) compared with female patients (19.7%) (P < 0.05; χ2). Chills, jaundice, vomiting, weakness, diarrhea, and kidney failure/problems were significantly (P < 0.05; χ2) exhibited at a higher frequency in seropositive, rather than seronegative patients. Using the MAT on 100 sera tested, 98 (98%) were seropositive, of which the serogroup Icterohaemorrhagiae was most prevalent with the detection of serovars Copenhageni (70%), Icterohaemorrhagiae (67%), and Mankarso (29%). CONCLUSIONS: Since only 13.1% of the suspected cases of leptospirosis were seropositive for IgM ELISA antibodies, other clinical conditions may have been responsible for the clinical manifestations observed, or the patient may have had chronic leptospirosis (IgG). In the Caribbean, serovars of the serogroup Icterohaemorrhagiae were responsible for most infections in the cases tested.

Frequency of seropositivity for Coxiella burnetii immunoglobulins in livestock and abattoir workers in Trinidad.

Coxiella burnetii is a zoonotic, rickettsial pathogen which causes mild and severe diseases often referred to as Q-fever in humans, particularly those occupationally exposed. This study determined the seropositivity for Coxiella burnetii IgM immunoglobulins using the enzyme immunoassay (EIA) in livestock and abattoir workers in Trinidad and related to selected personal characteristics to seroprevalence. Overall, of the 455 humans whose serum samples were tested, 20 (4.4%) were seropositive for C. burnetii IgM immunoglobulin, comprising 13 (4.6%) out of 283 livestock workers, 4 (4.7%) out of 85 abattoir workers and 3 (3.4%) out of 87 office workers (P>0.05; Chi 2). The age, sex and race of workers were not significantly associated with the occurrence of acute Q-fever (P>0.05; Chi 2). This is considered the first documentation of Q-fever in the human population in Trinidad. It is difficult to assess the impact of the disease in the country since the disease is not routinely tested for in the local hospitals or diagnostic laboratories.

Frequency of Detection of Escherichia coli, Salmonella spp., and Campylobacter spp. in the Faeces of Wild Rats (Rattus spp.) in Trinidad and Tobago.

The study was conducted to determine the frequency of isolation of Salmonella, Campylobacter and E. coli O157 in the faecal samples of rats trapped across the regional corporations in Trinidad and to assess their resistance to antimicrobial agents. A total of 204 rats were trapped for the detection of selected bacteria. Standard methods were used to isolate Salmonella, Campylobacter and E. coli O157. Characterization of E. coli was done on sorbitol MacConkey agar to determine non-sorbitol fermentation, blood agar to determine haemolytic and mucoid colonies and by using E. coli O157 antiserum to determine O157 strain. The disc diffusion method was used to determine resistance to nine antimicrobial agents. Of the 204 rats, 4 (2.0%), 7 (3.4%) and 171 (83.8%) were positive for Salmonella spp., Campylobacter spp. and E. coli, respectively. Of the 171 isolates of E. coli tested 0 (0.0%), 25 (14.6%) and 19 (11.1%) were haemolytic, mucoid and non-sorbitol fermenters, respectively. All isolates were negative for the O157 strain. The frequency of resistance to the 9 antimicrobial agents tested was 75% (3 of 4) for Salmonella, 85.7% (6 of 7) of Campylobacter spp. and 36.3% (62 of 171) for E. coli (P < .05; χ(2)).

Human leptospirosis in the Caribbean, 1997-2005: characteristics and serotyping of clinical samples from 14 countries / Leptospirosis humana en el Caribe entre 1997 y 2005: características y serotipificación de muestras clínicas de 14 países

OBJECTIVE: To determine the frequency of human leptospirosis in the sera of suspected clinical cases sent by 14 Caribbean countries for diagnosis to a regional laboratory in 1997-2005. METHODS: All serum samples were initially tested using the immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA) for leptospirosis. Demographic data (such as age and sex), month of the year and clinical manifestations that had been observed by the attending physician were related to seropositivity. The microscopic agglutination test (MAT) was used to serotype sera using a panel of 23 international serovars. RESULTS: Of 3 455 samples tested, 452 (13.1 percent) were seropositive for IgM antibodies to leptospirosis by the ELISA, with frequencies significantly (P < 0.05; χ2) different across countries and years. Among seropositive patients, the frequency of detection of leptospirosis (23.1 percent) was significantly higher in the age groups 1-20 years and 31-40 years combined compared with other age groups; and in male patients (72.1 percent) compared with female patients (19.7 percent) (P < 0.05; χ2). Chills, jaundice, vomiting, weakness, diarrhea, and kidney failure/problems were significantly (P < 0.05; χ2) exhibited at a higher frequency in seropositive, rather than seronegative patients. Using the MAT on 100 sera tested, 98 (98 percent) were seropositive, of which the serogroup Icterohaemorrhagiae was most prevalent with the detection of serovars Copenhageni (70 percent), Icterohaemorrhagiae (67 percent), and Mankarso (29 percent). CONCLUSIONS: Since only 13.1 percent of the suspected cases of leptospirosis were seropositive for IgM ELISA antibodies, other clinical conditions may have been responsible for the clinical manifestations observed, or the patient may have had chronic leptospirosis (IgG). In the Caribbean, serovars of the serogroup Icterohaemorrhagiae were responsible for most infections in the cases tested.

OBJETIVO: Determinar la frecuencia de leptospirosis humana en el suero de presuntos casos clínicos enviados por 14 países del Caribe a un laboratorio regional para la confirmación del diagnóstico entre 1997 y 2005. MÉTODOS: Todas las muestras de suero se analizaron inicialmente mediante el ensayo inmunoenzimático de adsorción (ELISA) para detectar inmunoglobulina M (IgM) contra Leptospira. Se relacionó la seropositividad con datos demográficos (como la edad y el sexo), el mes del año y las manifestaciones clínicas observadas por el médico a cargo. Se usó la prueba de aglutinación microscópica para serotipificar los sueros con un grupo de 23 serovariedades internacionales. RESULTADOS: De las 3 455 muestras analizadas por ELISA, 452 (13,1 por ciento) fueron seropositivas para anticuerpos IgM contra Leptospira, con frecuencias significativamente diferentes (P < 0,05; χ2) según el país y el año. En los pacientes seropositivos, la frecuencia de detección de leptospirosis (23,1 por ciento) fue significativamente mayor en los grupos etarios de 1 a 20 años y de 31 a 40 años combinados, en comparación con otros grupos de edad; y mayor en los varones (72,1 por ciento) en comparación con las mujeres (19,7 por ciento) (P < 0,05; χ2). Los escalofríos, la ictericia, los vómitos, la debilidad, la diarrea y la insuficiencia o los trastornos renales fueron significativamente más frecuentes (P < 0,05; χ2) en los pacientes seropositivos que en los seronegativos. De los 100 sueros que se analizaron con la prueba de aglutinación microscópica, 98 (98 por ciento) fueron seropositivos, y entre estos el serogrupo Icterohaemorrhagiae fue el más frecuente, con detección de las serovariedades Copenhageni (70 por ciento), Icterohaemorrhagiae (67 por ciento) y Mankarso (29 por ciento). CONCLUSIONES: Ya que solo 13,1 por ciento de los presuntos casos de leptospirosis fueron seropositivos por ELISA para anticuerpos IgM, las manifestaciones clínicas observadas pueden haberse debido a otras enfermedades, o el paciente puede haber tenido leptospirosis crónica (con anticuerpos IgG). En los casos analizados en el Caribe, las serovariedades del serogrupo Icterohaemorrhagiae causaron la mayoría de las infecciones.

Frequency of seropositivity for Coxiella burnetii immunoglobulins in livestock and abattoir workers in Trinidad

Coxiella burnetii is a zoonotic, rickettsial pathogen which causes mild and severe diseases often referred to as Q-fever in humans, particularly those occupationally exposed. This study determined the seropositivity for Coxiella burnetii IgM immunoglobulins using the enzyme immunoassay (EIA) in livestock and abattoir workers in Trinidad and related to selected personal characteristics to seroprevalence. Overall, of the 455 humans whose serum samples were tested, 20 (4.4%) were seropositive for C. burnetii IgM immunoglobulin, comprising 13 (4.6%) out of 283 livestock workers, 4 (4.7%) out of 85 abattoir workers and 3 (3.4%) out of 87 office workers (P>0.05; ö2).The age, sex and race of workers were not significantly associated with the occurrence of acute Q-fever (P>0.05; ö2). This is considered the first documentation of Q-fever in the human population in Trinidad. It is difficult to assess the impact of the disease in the country since the disease is not routinely tested for in the local hospitals or diagnostic laboratories.

Frequency of detection of Escherichia coli, Salmonella spp., and Campylobacter spp. in the faeces of wild rats (Rattus spp.) in Trinidad and Tobago

The study was conducted to determine the frequency of isolation of Salmonella, Campylobacter and E. coli O157 in the faecal samples of rats trapped across the regional corporations in Trinidad and to assess their resistance to antimicrobial agents. A total of 204 rats were trapped for the detection of selected bacteria. Standard methods were used to isolate Salmonella, Campylobacter and E. coli O157. Characterization of E. coli was done on sorbitol MacConkey agar to determine non-sorbitol fermentation, blood agar to determine haemolytic and mucoid colonies and by using E. coli O157 antiserum to determine O157 strain. The disc diffusion method was used to determine resistance to nine antimicrobial agents. Of the 204 rats, 4 (2.0%), 7 (3.4%) and 171 (83.8%) were positive for Salmonella spp., Campylobacter spp. and E. coli, respectively. Of the 171 isolates of E. coli tested 0 (0.0%), 25 (14.6%) and 19 (11.1%) were haemolytic, mucoid and non-sorbitol fermenters, respectively. All isolates were negative for the O157 strain. The frequency of resistance to the 9 antimicrobial agents tested was 75% (3 of 4) for Salmonella, 85.7% (6 of 7) of Campylobacter spp. and 36.3% (62 of 171) for E. coli (P < .05; χ(2)).

Virulence of Brucella abortus isolated from cattle and water buffalo.

Brucellosis has been documented in domestic water buffalo (Bubalus bubalis) but published literature is limited despite the importance of this species in tropical agricultural systems. The objective of this study was to compare the virulence of Brucella abortus isolates recovered from cattle and water buffalo. Nineteen strains of B. abortus from cattle and domestic water buffalo in Trinidad were intraperitoneally inoculated into BALB/c mice. Spleens were cultured for B. abortus and histopathological severity scores were calculated based on lymphoid depletion, lymphoid necrosis, splenitis, and macrophage accumulation. A general linear model approach was used to estimate the effect of isolate source (cattle versus water buffalo) on virulence. Isolates of water buffalo origin were significantly less virulent in the mouse model based on recovered B. abortus from splenic tissues, spleen/weight ratio, and lymphoid necrosis but not overall histopathological severity scores. Further investigation of isolates recovered from water buffalo might provide the key to the development of procedures for brucellosis control in tropical environments.

Comparative study on responses of cattle and water buffalo (Bubalus bubalis) to experimental inoculation of Brucella abortus biovar 1 by the intraconjunctival route--a preliminary report

The preliminary study was conducted to assess the virulence of a strain of Brucella abortus (1969D) and to compare the susceptibility of water buffalo and cattle calves to infection by the intraconjunctival route. Seven of each cattle and water buffalo (Bubalus bubalis) calves aged 3-6 months were inoculated intraconjunctivally with counts ranging from 1.5 ž 10(7) to 1.7 ž 10(10) colony forming units of B. abortus. Animals were monitored over an 8-week period for clinical manifestations and serological and hematological evidence of infection. At slaughter, eight lymph nodes from each animal were sampled for bacteriological and histopathological assessments. Lymph nodes from three water buffalo (43%) and five cattle (71%) yielded B. abortus (P=0.048). Parotid/prescapular lymph nodes were most sensitive in detecting B. abortus. Our data suggest that B. abortus strain 1969D may be used as challenge strain, and water buffalo appeared to have a lower susceptibility to B. abortus infection than cattle.