Antimicrobial resistance determinants and susceptibility profiles of pneumococcal isolates recovered in Trinidad and Tobago.

OBJECTIVES: In Latin America and the Caribbean, pneumococcal infections are estimated to account for 12000-18000 deaths, 327000 pneumonia cases, 4000 meningitis cases and 1229 sepsis cases each year in children under five years old. Pneumococcal antimicrobial resistance has evolved into a worldwide health problem in the last few decades. This study aimed to determine the antimicrobial susceptibility profiles of pneumococcal isolates collected in Trinidad and Tobago and their associated genetic determinants. METHODS: Whole-genome sequences were obtained from 98 pneumococcal isolates recovered at several regional hospitals, including 83 invasive and 15 non-invasive strains, recovered before (n=25) and after (n=73) introduction of pneumococcal conjugate vaccines (PCVs). A bioinformatics pipeline was used to identify core genomic and accessory elements conferring antimicrobial resistance phenotypes, including ß-lactam non-susceptibility. RESULTS AND DISCUSSION: Forty-one isolates (41.8%) were predicted as resistant to at least one antimicrobial class, including 13 (13.3%) resistant to at least three classes. The most common serotypes associated with antimicrobial resistance were 23F (n=10), 19F (n=8), 6B (n=6) and 14 (n=5). The most common serotypes associated with penicillin non-susceptibility were 19F (n=7) and 14 (n=5). Thirty-nine isolates (39.8%) were positive for PI-1 or PI-2 type pili: 30 (76.9%) were PI-1+, 4 (10.3%) were PI-2+ and 5 (12.8%) were positive for both PI-1 and PI-2. Of the 13 multidrug-resistant isolates, 10 belonged to globally distributed clones PMEN3 and PMEN14 and were isolated in the post-PCV period, suggesting clonal expansion.

Serotypes and genotypes of Streptococcus pneumoniae isolates from Trinidad and Tobago.

OBJECTIVES: There are currently 94 known pneumococcal capsular polysaccharide serotypes and their prevalence differs by geographic region and the period studied. Streptococcus pneumoniae infections have been diagnosed clinically in Trinidad and Tobago and other Caribbean countries, however data on the serotype and sequence type distributions in this country are limited. The objective of this study was to determine serotypes and multilocus sequence types (MLSTs) of invasive and non-invasive pneumococcal isolates from Trinidad and Tobago. METHODS: Ninety-eight pneumococcal isolates from several regional hospitals in the country were analyzed using both standard microbiological methods and molecular analysis. These isolates included invasive (n=83) and selected non-invasive (n=15) strains recovered before (n=25) and after (n=73) the introduction of the pneumococcal conjugate vaccine. RESULTS: More than half of the isolates (54.1%) were recovered from children under 15 years of age, with the largest proportion being from children under 2 years of age (24.5%). The most prevalent serotypes were 19F (18.4%), 6B (15.3%), 23F (14.3%), 3 (11.2%), 19A (6.1%), 6A (5.1%), 14 (5.1%), and 9V (4.1%). The most common serotype/MLST combinations were 6B/ST138 (n=10, 10.2%), 3/ST180 (n=5, 5.1%), 23F/ST629 (n=5, 5.1%), 19F/ST8398 (n=4, 4.1%), and three each of 6B/ST145, 14/9V/ST156, 9V/ST162, 19A/320, and 3/ST10440. CONCLUSIONS: This report provides the first glimpse of the prevailing pneumococcal sequence types in the country. Most of the isolates represented serotypes in the 10-valent (61.2% of isolates) and 13-valent (83.7%) pneumococcal conjugate vaccines. A detailed population study is warranted to fully determine the circulating pneumococcal sequence types. Furthermore, the implementation of an effective and continuous surveillance system in Trinidad and Tobago is paramount to monitor vaccine impact.

Methicillin sensitive Staphylococcus aureus producing Panton-Valentine leukocidin toxin in Trinidad & Tobago: a case report.

INTRODUCTION: Certain Staphylococcus aureus strains produce Panton-Valentine leukocidin, a toxin that lyses white blood cells causing extensive tissue necrosis and chronic, recurrent or severe infection. This report documents a confirmed case of methicillin-sensitive Staphylococcus aureus strain harboring Panton-Valentine leukocidin genes from Trinidad and Tobago. To the best of our knowledge, this is the first time that such a case has been identified and reported from this country. CASE PRESENTATION: A 13-year-old Trinidadian boy of African descent presented with upper respiratory symptoms and gastroenteritis-like syptoms. About two weeks later he was re-admitted to our hospital complaining of pain and weakness affecting his left leg, where he had received an intramuscular injection of an anti-emetic drug. He deteriorated and developed septic arthritis, necrotizing fasciitis and septic shock with acute respiratory distress syndrome, leading to death within 48 hours of admission despite intensive care treatment. The infection was caused by S. aureus. Bacterial isolates from specimens recovered from our patient before and after his death were analyzed using microarray DNA analysis and spa typing, and the results revealed that the S. aureus isolates belonged to clonal complex 8, were methicillin-susceptible and positive for Panton-Valentine leukocidin. An autopsy revealed multi-organ failure and histological tissue stains of several organs were also performed and showed involvement of his lungs, liver, kidneys and thymus, which showed Hassal's corpuscles. CONCLUSION: Rapid identification of Panton-Valentine leukocidin in methicillin-sensitive S. aureus isolates causing severe infections is necessary so as not to miss their potentially devastating consequences. Early feedback from the clinical laboratories is crucial.

Methicillin sensitive Staphylococcus aureus producing Panton-Valentine leukocidin toxin in Trinidad & Tobago: a case report

INTRODUCTION: Certain Staphylococcus aureus strains produce Panton-Valentine leukocidin, a toxin that lyses white blood cells causing extensive tissue necrosis and chronic, recurrent or severe infection. This report documents a confirmed case of methicillin-sensitive Staphylococcus aureus strain harboring Panton-Valentine leukocidin genes from Trinidad and Tobago. To the best of our knowledge, this is the first time that such a case has been identified and reported from this country. CASE PRESENTATION: A 13-year-old Trinidadian boy of African descent presented with upper respiratory symptoms and gastroenteritis-like syptoms. About two weeks later he was re-admitted to our hospital complaining of pain and weakness affecting his left leg, where he had received an intramuscular injection of an anti-emetic drug. He deteriorated and developed septic arthritis, necrotizing fasciitis and septic shock with acute respiratory distress syndrome, leading to death within 48 hours of admission despite intensive care treatment. The infection was caused by S. aureus. Bacterial isolates from specimens recovered from our patient before and after his death were analyzed using microarray DNA analysis and spa typing, and the results revealed that the S. aureus isolates belonged to clonal complex 8, were methicillin-susceptible and positive for Panton-Valentine leukocidin. An autopsy revealed multi-organ failure and histological tissue stains of several organs were also performed and showed involvement of his lungs, liver, kidneys and thymus, which showed Hassal's corpuscles. CONCLUSION: Rapid identification of Panton-Valentine leukocidin in methicillin-sensitive S. aureus isolates causing severe infections is necessary so as not to miss their potentially devastating consequences. Early feedback from the clinical laboratories is crucial.

Experimental evaluation of ethanolic extract of Carapa guianensis L. Leaf for its wound healing activity using three wound models.

The leaves of Carapa guianensis have been used to treat ulcers, skin parasites, and skin problems. The ethanolic extract of C. guianensis leaf was evaluated for its antibacterial and wound healing activity using excision, incision and dead space wound models in rats. The animals were randomly divided into two groups (n = 6) in all the models. In the excision wound model test group animals were treated topically with the leaf extract (250 mg kg(-1) body weight) whereas, control animals were treated with petroleum jelly. In the incision and dead space wound models, the test group animals were treated with extract (250 mg kg(-1) day(-1)) orally by mixing in drinking water and the control group animals were maintained with plain drinking water. Healing was assessed by the rate of wound contraction, period of epithelialization, skin breaking strength, granulation tissue weight and hydoxyproline content. On Day 15 extract-treated animals exhibited 100% reduction in the wound area when compared to controls (95%) with significant decrease in the epithelialization period. The extract failed to demonstrate antibacterial activity. Skin breaking strength (P < .001), wet (P < .002) and dry (P < .02) granulation tissue and hydroxyproline content (P < .03) were significantly higher in extract treated animals. The increased rate of wound contraction, skin breaking strength and hydroxyproline content supports potential application of C. guianensis in wound healing.

Investigation of the wound healing activity of Carapa guianensis L. (Meliaceae) bark extract in rats using excision, incision, and dead space wound models

The objective of our study is to investigate the wound healing activity of the bark extract of Carapa guianensis in rats using three different wound models. The animals were randomly divided into two groups of six each in all the models. Test group animals were treated topically with the bark extract (200 mg/kg of body weight), and the controls were treated with petroleum jelly in the excision wound model. In the incision and dead space wound models the test group animals were treated with the extract of C. guianensis (200 mg/kg/day) orally by mixing in drinking water, and the control group animals were maintained with plain drinking water. Healing was assessed by the rate of wound contraction, period of epithelialization, skin breaking strength, granulation tissue weight, and hydoxyproline content. Antimicrobial activities of the extract against the microorganisms were also assessed. On day 15 extract-treated animals exhibited 99% reduction in the wound area compared to controls (93%). The extract-treated wounds were found to epithelialize faster than controls (P < .02). The skin breaking strength was significantly higher in extract-treated animals compared to controls (P < .001). The weight and hydroxyproline content of granulation tissue were significantly increased compared to controls. These observations support the use of C. guianensis is in the management of wound healing.

Investigation of the wound healing activity of Carapa guianensis L. (Meliaceae) bark extract in rats using excision, incision, and dead space wound models.

The objective of our study is to investigate the wound healing activity of the bark extract of Carapa guianensis in rats using three different wound models. The animals were randomly divided into two groups of six each in all the models. Test group animals were treated topically with the bark extract (200 mg/kg of body weight), and the controls were treated with petroleum jelly in the excision wound model. In the incision and dead space wound models the test group animals were treated with the extract of C. guianensis (200 mg/kg/day) orally by mixing in drinking water, and the control group animals were maintained with plain drinking water. Healing was assessed by the rate of wound contraction, period of epithelialization, skin breaking strength, granulation tissue weight, and hydoxyproline content. Antimicrobial activities of the extract against the microorganisms were also assessed. On day 15 extract-treated animals exhibited 99% reduction in the wound area compared to controls (93%). The extract-treated wounds were found to epithelialize faster than controls (P < .02). The skin breaking strength was significantly higher in extract-treated animals compared to controls (P < .001). The weight and hydroxyproline content of granulation tissue were significantly increased compared to controls. These observations support the use of C. guianensis is in the management of wound healing.

Emergence of KPC-producing Pseudomonas aeruginosa in Trinidad and Tobago.

In 2006, the first isolate of KPC-2-producing Pseudomonas aeruginosa in the world was identified in Colombia. Recently, similar strains have been reported in Puerto Rico. We now report KPC-2-producing P. aeruginosa in Trinidad and Tobago. Surveillance for similar strains is warranted, considering their wide geographic spread and known association with mobile genetic elements.

Emergence of KPC-producing Pseudomonas aeruginosa in Trinidad and Tobago.

In 2006, the first isolate of KPC-2-producing Pseudomonas aeruginosa in the world was identified in Colombia. Recently, similar strains have been reported in Puerto Rico. We now report KPC-2-producing P. aeruginosa in Trinidad and Tobago. Surveillance for similar strains is warranted, considering their wide geographic spread and known association with mobile genetic elements.

Phenotypic detection and occurrence of extended-spectrum beta-lactamases in clinical isolates of Klebsiella pneumoniae and Escherichia coli at a tertiary hospital in Trinidad & Tobago.

The incidence and distribution of ESBL producing microorganisms such as E. coli and K. pneumoniae have been demonstrated and varies in different health care facilities and as well as other countries This study was carried out to determine the frequency of occurrence and the antimicrobial susceptibility pattern of ESBL producing E. coli and K. pneumoniae species from clinical isolates at a tertiary hospital in Trinidad & Tobago. Standard microbiological procedures and automated MicroScan System was used to identify, screen for putative ESBL production and determine antimicrobial susceptibility of 1,118 clinical isolates of Enterobacteriaceae species at the microbiology laboratory of the Eric Williams Medical Science Complex, Trinidad & Tobago over a 36 months period. All ESBL producing isolates flagged by the automated system were further confirmed by E-test method. The E-test confirmed a 15.2 per cent ESBL rate among the K. pneumoniae isolates and 9.3 per cent among the E. coli isolates. There was also a 1.8 per cent rate of ESBL production in K. pneumoniae and 0.2 per cent in E. coli isolates from specimens received from community health facilities into the laboratory. Isolates recovered from the intensive care unit of the hospital had 2.1 per cent E. coli and 8.2 per cent K. pneumoniae ESBL producers. Although all ESBL positive isolates were completely susceptible to imipenem and meropenem; and all positive K. pneumoniae isolates were susceptible to amikacin, there was a low susceptibility of ESBL positive E. coli to the aminoglycosides. However, susceptibility of these ESBL producing isolates to the fluoroquinolones varied. There is a high rate of ESBL production among isolates of E. coli and K. pneumoniae at this hospital that is linked to the extensive inappropriate use of third generation cephalosporins in the country. Further molecular studies are needed to characterize the types of these ESBL prevailing in the country.

Phenotypic detection and occurrence of extended-spectrum beta-lactamases in clinical isolates of Klebsiella pneumoniae and Escherichia coli at a tertiary Hospital in Trinidad & Tobago

The incidence and distribution of ESBL producing microorganisms such as E. coli and K. pneumoniae have been demonstrated and varies in different health care facilities and as well as other countries This study was carried out to determine the frequency of occurrence and the antimicrobial susceptibility pattern of ESBL producing E. coli and K. pneumoniae species from clinical isolates at a tertiary hospital in Trinidad & Tobago. Standard microbiological procedures and automated MicroScan System was used to identify, screen for putative ESBL production and determine antimicrobial susceptibility of 1,118 clinical isolates of Enterobacteriaceae species at the microbiology laboratory of the Eric Williams Medical Science Complex, Trinidad & Tobago over a 36 months period. All ESBL producing isolates flagged by the automated system were further confirmed by E-test method. The E-test confirmed a 15.2 percent ESBL rate among the K. pneumoniae isolates and 9.3 percent among the E. coli isolates. There was also a 1.8 percent rate of ESBL production in K. pneumoniae and 0.2 percent in E. coli isolates from specimens received from community health facilities into the laboratory. Isolates recovered from the intensive care unit of the hospital had 2.1 percent E. coli and 8.2 percent K. pneumoniae ESBL producers. Although all ESBL positive isolates were completely susceptible to imipenem and meropenem; and all positive K. pneumoniae isolates were susceptible to amikacin, there was a low susceptibility of ESBL positive E. coli to the aminoglycosides. However, susceptibility of these ESBL producing isolates to the fluoroquinolones varied. There is a high rate of ESBL production among isolates of E. coli and K. pneumoniae at this hospital that is linked to the extensive inappropriate use of third generation cephalosporins in the country. Further molecular studies are needed to characterize the types of these ESBL prevailing in the country.

Phenotypic detection and occurrence of extended-spectrum beta-lactamases in clinical isolates of Klebsiella pneumoniae and Escherichia coli at a tertiary hospital in Trinidad & Tobago.

The incidence and distribution of ESBL producing microorganisms such as E. coli and K. pneumoniae have been demonstrated and varies in different health care facilities and as well as other countries This study was carried out to determine the frequency of occurrence and the antimicrobial susceptibility pattern of ESBL producing E. coli and K. pneumoniae species from clinical isolates at a tertiary hospital in Trinidad & Tobago. Standard microbiological procedures and automated MicroScan System was used to identify, screen for putative ESBL production and determine antimicrobial susceptibility of 1,118 clinical isolates of Enterobacteriaceae species at the microbiology laboratory of the Eric Williams Medical Science Complex, Trinidad & Tobago over a 36 months period. All ESBL producing isolates flagged by the automated system were further confirmed by E-test method. The E-test confirmed a 15.2% ESBL rate among the K. pneumoniae isolates and 9.3% among the E. coli isolates. There was also a 1.8% rate of ESBL production in K. pneumoniae and 0.2% in E. coli isolates from specimens received from community health facilities into the laboratory. Isolates recovered from the intensive care unit of the hospital had 2.1% E. coli and 8.2% K. pneumoniae ESBL producers. Although all ESBL positive isolates were completely susceptible to imipenem and meropenem; and all positive K. pneumoniae isolates were susceptible to amikacin, there was a low susceptibility of ESBL positive E. coli to the aminoglycosides. However, susceptibility of these ESBL producing isolates to the fluoroquinolones varied. There is a high rate of ESBL production among isolates of E. coli and K. pneumoniae at this hospital that is linked to the extensive inappropriate use of third generation cephalosporins in the country. Further molecular studies are needed to characterize the types of these ESBL prevailing in the country.

Molecular epidemiology of methicillin-resistant Staphylococcus aureus isolates from regional hospitals in Trinidad and Tobago.

OBJECTIVES: Methicillin-resistant Staphylococcus aureus (MRSA), first reported in a British hospital in the early 1960s, has now reached global proportions. Geographic spread of one or several MRSA clones in a city, country, and even among countries and continents has been identified by molecular techniques. We sought to determine whether clonal spread of MRSA has occurred in Trinidad and Tobago from all MRSA isolates collected between 2000 and 2001. METHODS: Clinical isolates of MRSA from three major hospitals in Trinidad and Tobago were identified by standard laboratory methods and analyzed using multiplex polymerase chain reaction (PCR) and pulsed-field gel electrophoresis (PFGE) after SmaI digestion. RESULTS: There was a 12.8% prevalence of MRSA in three major regional hospitals in Trinidad and Tobago. All 60 randomly selected MRSA strains from these hospitals produced similar PFGE banding patterns, suggesting a genetic relatedness among strains and that they belonged to a single clonal family. All isolates were negative for the Panton-Valentine leukocidin gene (pvl). These strains shared a PFGE banding pattern approximately (96%) the same as a Canadian strain called CMRSA-6 in the Canadian National Microbiology Laboratory database. CONCLUSIONS: We conclude that only one major PFGE genotype of MRSA clone is circulating among the three major regional hospitals in Trinidad and Tobago suggesting one of three possible scenarios of microevolution: (1) all were from the dissemination of a single epidemic MRSA clone prevailing in these hospitals in Trinidad and Tobago; or (2) MRSA in Trinidad and Tobago is evolving more slowly than in other countries; or (3) that if other MRSA clones have been present in Trinidad and Tobago, they have not persisted.

Prevalence and antimicrobial susceptibility pattern of methicillin resistant Staphylococcus aureus isolates from Trinidad & Tobago

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) has become increasingly prevalent worldwide since it was first reported in a British hospital. We therefore sought to document comprehensively the prevalence and antimicrobial susceptibility pattern of MRSA isolates in Trinidad and Tobago. METHODS: All Staphylococcus aureus isolates encountered in routine clinical specimens received at major hospitals in the country between 2000 and 2001 were identified morphologically and biochemically by standard laboratory procedures including latex agglutination test. MRSA screening was performed using Mueller-Hinton agar containing 6 g oxacillin and 4 per cent NaCl, latex agglutination test (Denka Seiken Co. Ltd, Tokyo, Japan) and E-test system (AB Biodisk, Solna, Sweden). Susceptibility to antimicrobial agents was determined by the modified Kirby Bauer disc diffusion method while methicillin MICs were determined with E-test system. RESULTS: Of 1,912 S. aureus isolates received, 12.8 per cent were methicillin (oxacillin) resistant. Majority of the isolates were recovered from wound swabs (86.9 per cent) and the least in urine (0.4 per cent) specimens. Highest number of isolates was encountered in the surgical (62.3 per cent) and the least from obstetrics and gynaecology (1.6 per cent) facilities respectively. Large proportions of methicillin sensitive isolates are >85 per cent sensitive to commonly used and available antimicrobials in the country. All MRSA isolates were resistant to ceftriaxone, erythromycin, gentamicin and penicillin but were 100 per cent sensitive to vancomycin, rifampin and chloramphenicol. CONCLUSION: There is a progressive increase in MRSA prevalence in the country but the present rate is still low in comparison to values in some other countries. Vancomycin is still the drug of choice for treating multidrug resistant MRSA infections.

A cross-sectional study of isolates from sputum samples from bacterial pneumonia patients in Trinidad.

We determined the frequency of Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, and Gram-negative enteric bacteria (GNEB) in pneumonia patients, determined the antibiograms of these pathogens, and investigated the relationship between pneumonia and selected risk factors. Sputum and demographic data were collected from 124 pneumonia patients. Sputum was cultured for S. aureus, GNEB, H. influenzae and S. pneumoniae. The disc diffusion method was used to determine resistance to eight antimicrobial agents. Among the 124 sputum samples, eight (6.5%) were positive for S. aureus, 15 (12.1%) for GNEB, two (1.6%) for S. pneumoniae and one (0.8%) for H. influenzae. Hospitals, gender, ethnicity, co-morbidities and symptoms did not significantly (p > 0.05; chi2) affect the prevalence of these bacteria. GNEB infection was most prevalent (47%) in patients over 70 years old. Gentamicin and levofloxacin were the most effective against these bacteria.

A cross-sectional study of isolates from sputum samples from bacterial pneumonia patients in Trinidad

We determined the frequency of Streptococcus pneumoniae, Haemophilus influenzae,Staphylococcus aureus, and Gram-negative enteric bacteria (GNEB) in pneumonia patients,determined the antibiograms of these pathogens, and investigated the relationship between pneumonia and selected risk factors. Sputum and demographic data were collected from 124pneumonia patients. Sputum was cultured for S. aureus, GNEB, H. influenzae and S. pneumoniae.The disc diffusion method was used to determine resistance to eight antimicrobial agents. Amongthe 124 sputum samples, eight (6.5%) were positive for S. aureus, 15 (12.1%) for GNEB, two(1.6%) for S. pneumoniae and one (0.8%) for H. influenzae. Hospitals, gender, ethnicity, comorbidities and symptoms did not significantly (p > 0.05; ö2) affect the prevalence of these bacteria.GNEB infection was most prevalent (47%) in patients over 70 years old. Gentamicin and levofloxacin were the most effective against these bacteria.

A cross-sectional study of isolates from sputum samples from bacterial pneumonia patients in Trinidad

We determined the frequency of Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, and Gram-negative enteric bacteria (GNEB) in pneumonia patients, determined the antibiograms of these pathogens, and investigated the relationship between pneumonia and selected risk factors. Sputum and demographic data were collected from 124 pneumonia patients. Sputum was cultured for S. aureus, GNEB, H. influenzae and S. pneumoniae. The disc diffusion method was used to determine resistance to eight antimicrobial agents. Among the 124 sputum samples, eight (6.5 percent) were positive for S. aureus, 15 (12.1 percent) for GNEB, two (1.6 percent) for S. pneumoniae and one (0.8 percent) for H. influenzae. Hospitals, gender, ethnicity, co-morbidities and symptoms did not significantly (p > 0.05; chi2) affect the prevalence of these bacteria. GNEB infection was most prevalent (47 percent) in patients over 70 years old. Gentamicin and levofloxacin were the most effective against these bacteria.

Frequency and characteristics of selected enteropathogens in fecal and rectal specimens from childhood diarrhea in Trinidad, 1998-2000.

OBJECTIVE: To determine the prevalence and characteristics of selected enteric pathogens in diarrheic children in six counties of the island of Trinidad. METHODS: This cross-sectional study was conducted from April 1998 through March 2000. Fecal or rectal swab specimens from children (<12 years) were collected and then processed, using standard methods, to detect Salmonella spp., Shigella spp., enteropathogenic Escherichia coli (EPEC), Campylobacter spp., Yersinia spp., Cryptosporidium parvum, and parasite ova. The antibiograms of the enteropathogens were determined using the disk diffusion method. RESULTS: A total of 236 samples were processed; 86 samples originated directly from 17 heath centers in two counties (St. George East and St. George West), while 150 samples were obtained from the Trinidad Public Health Laboratory, having been submitted by private practitioners and personnel from six counties in Trinidad. Of the 236 samples, 33 (14.0%) were positive for Shigella, 4 (1.7%) for Salmonella, and 1 (0.4%) for EPEC. Two of the samples (0.8%) were positive for Campylobacter jejuni, while 1 sample (0.4%) was positive for hookworm ova. All the samples were negative for Cryptosporidium parvum and Yersinia spp. With the 86 samples collected directly from the health centers, in St. George East County the frequency of Shigella was 20.0% (12 of 60), compared with 26.9% (7 of 26) for samples from St. George West County, but the difference was not statistically significant (P>0.05 with the chi-square test). For the 150 samples from the six counties that had been submitted directly to the Trinidad Public Health Laboratory, 14 of them (9.3%) were positive for Shigella, a figure statistically significantly lower than that found with the samples sampled directly from the health centers (P<0.05 with the chi-square test). Sh. sonnei was the predominant serotype detected, accounting for 28 of the 33 Shigella isolates (84.8%) recovered from the 236 samples. Overall, the frequency of detection of enteropathogens had no seasonal pattern nor relationship to the county of origin. Of the 37 isolates of Salmonella and Shigella tested for antimicrobial sensitivity, all of them were sensitive to ciprofloxacin, gentamicin, and cefotaxime. In terms of resistance, 3 of the 37 isolates (8.1%) exhibited resistance to ampicillin, 1 (2.7%) to chloramphenicol, and 1 (2.7%) to sulfamethoxazole/ trimethoprim. CONCLUSION: Of the enteropathogens for which assays were done, Shigella sonnei was the most prevalent, and it has the highest probability of being an important etiological agent of childhood diarrhea in Trinidad.

Frequency and characteristics of selected enteropathogens in fecal and rectal specimens from childhood diarrhea in Trinidad, 1998-2000

Objective. To determine the prevalence and characteristics of selected enteric pathogens in diarrheic children in six counties of Trinidad. Methods. This cross-sectional study was conducted from April 1998 through March 2000, using standard methods, to detect Salmonella spp., Shigela spp., enteropathogenic Escherichia coli (EPEC), Campylobacter spp., Yersinia spp., Cryptosporidium parvum, and parasite ova. The antibiograms of the enteropathogens were determined using disk diffusion method.Results. A total of 236 samples; 86 samples originated directly from 17 health centers in two counties (St. George East and St. George West), while 150 samples were obtained from Trinidad Public Health Laboratory, having been submitted by private practitioners and personel from six counties in Trinidad. Of the 236 samples, 33 (14.0 percent) were positive for Shigella, 4 (1.7 percent) for Salmonella, and 1 (0.4 percent) was positive for hook worm ova. All the samples were negative for Cryptosporidium parvum and Yersinia spp. With the 86 samples collected directly from the health centers, in St. George East County the frequency of Shigella was 20.0 percent (12 of 60), compared with 26.9 percent (7 of 26) for samples from St. George West County, but the difference was not statistically significant (P> 0.05 with the chi-square test). For the 150 samples from the six counties that had been submitted directly to the Trinidad Public Health Laboratory, 14 of them (9.3 percent) were positive for Shigella, a figure statistically significantly lower than that found with the samples sampled directly from the health centers (P< 0.05 with the chi-square test). Sh. sonnei was the predominant serotype detected, accounting for 28 of the 33 Shigella isolates (84.8 percent) recovered from the 236 samples. Overall, the frequency of detection of enteropathogens had no seasonal pattern nor relationship to the county of origin. Of the 37 isolates of Salmonella and Shigella tested for antimicrobial sensitivity, all of them were sensitive to ciprofloxacin, gentamicin, and cefotaxime. In terms of resistance, 3 of the 37 isolates (8.1 percent) exhibited resistance to ampicillin, 1 (2.7 percent) to chloramphenicol, and 1 (2.7 percent) to sulfamethoxazole/ trimethoprim. Conclusions. Of the enteropathogens for which assays were done, Shigella sonnei was the most prevalent, and it has the highest probability of being an important etiological agent of childhood diarrhea in Trinidad (AU)