Neuropsychiatric Systemic Lupus Erythematosus: Molecules Involved in Its Imunopathogenesis, Clinical Features, and Treatment.

Systemic lupus erythematosus (SLE) is an idiopathic chronic autoimmune disease that can affect any organ in the body, including the neurological system. Multiple factors, such as environmental (infections), genetic (many HLA alleles including DR2 and DR3, and genes including C4), and immunological influences on self-antigens, such as nuclear antigens, lead to the formation of multiple autoantibodies that cause deleterious damage to bodily tissues and organs. The production of autoantibodies, such as anti-dsDNA, anti-SS(A), anti-SS(B), anti-Smith, and anti-neuronal DNA are characteristic features of this disease. This autoimmune disease results from a failure of the mechanisms responsible for maintaining self-tolerance in T cells, B cells, or both. Immune complexes, circulating antibodies, cytokines, and autoreactive T lymphocytes are responsible for tissue injury in this autoimmune disease. The diagnosis of SLE is a rheumatological challenge despite the availability of clinical criteria. NPSLE was previously referred to as lupus cerebritis or lupus sclerosis. However, these terms are no longer recommended because there is no definitive pathological cause for the neuropsychiatric manifestations of SLE. Currently, the treatment options are primarily based on symptomatic presentations. These include the use of antipsychotics, antidepressants, and anxiolytic medications for the treatment of psychiatric and mood disorders. Antiepileptic drugs to treat seizures, and immunosuppressants (e.g., corticosteroids, azathioprine, and mycophenolate mofetil), are directed against inflammatory responses along with non-pharmacological interventions.

A healthy patient with positive mantoux test but negative quantiferon Gold assay and no evidence of risk factors - to treat or not to treat?

A 56-year-old woman who vaccinated as a child with the Bacillus Calmette-Guerin (BCG), now tests positive to the tuberculin skin test (TST) but test negative to the Quantiferon Gold assay. She has no history of tuberculosis contact and is asymptomatic. This dilemma now is, should be treated for tuberculosis or not, based only on the TST results? To prevent these falsepositive results with TST and avoid treatment with isoniazid (INH) it may be helpful to use interferon-gamma release assay (IGRA) instead, which unlike the TB skin test is not affected by prior BCG vaccination.

Molecular Typing of ST239-MRSA-III From Diverse Geographic Locations and the Evolution of the SCCmec III Element During Its Intercontinental Spread.

ST239-MRSA-III is probably the oldest truly pandemic MRSA strain, circulating in many countries since the 1970s. It is still frequently isolated in some parts of the world although it has been replaced by other MRSA strains in, e.g., most of Europe. Previous genotyping work (Harris et al., 2010; Castillo-Ramírez et al., 2012) suggested a split in geographically defined clades. In the present study, a collection of 184 ST239-MRSA-III isolates, mainly from countries not covered by the previous studies were characterized using two DNA microarrays (i) targeting an extensive range of typing markers, virulence and resistance genes and (ii) a SCCmec subtyping array. Thirty additional isolates underwent whole-genome sequencing (WGS) and, together with published WGS data for 215 ST239-MRSA-III isolates, were analyzed using in-silico analysis for comparison with the microarray data and with special regard to variation within SCCmec elements. This permitted the assignment of isolates and sequences to 39 different SCCmec III subtypes, and to three major and several minor clades. One clade, characterized by the integration of a transposon into nsaB and by the loss of fnbB and splE was detected among isolates from Turkey, Romania and other Eastern European countries, Russia, Pakistan, and (mainly Northern) China. Another clade, harboring sasX/sesI is widespread in South-East Asia including China/Hong Kong, and surprisingly also in Trinidad & Tobago. A third, related, but sasX/sesI-negative clade occurs not only in Latin America but also in Russia and in the Middle East from where it apparently originated and from where it also was transferred to Ireland. Minor clades exist or existed in Western Europe and Greece, in Portugal, in Australia and New Zealand as well as in the Middle East. Isolates from countries where this strain is not epidemic (such as Germany) frequently are associated with foreign travel and/or hospitalization abroad. The wide dissemination of this strain and the fact that it was able to cause a hospital-borne pandemic that lasted nearly 50 years emphasizes the need for stringent infection prevention and control and admission screening.

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.

Molecular characterization of antimicrobial resistance genes against Staphylococcus aureus isolates from Trinidad and Tobago.

Staphylococcus aureus continues to pose major public health challenges in many areas because of antibiotic resistance problems. In the Caribbean, especially Trinidad and Tobago, the challenge is not different. This study was performed to evaluate the antimicrobial resistance gene prevalence among S. aureus isolates in Trinidad and Tobago. Standard and molecular microbiological methods, including the Microscan automated system, DNA microarray and multi locus sequence typing (MLST) analysis, were performed on 309 clinical S. aureus isolates recovered from patients who were treated at three of the country's main health institutions. S. aureus exhibited susceptibilities ≥80% to eleven of the 19 antimicrobials tested against it, and these belong to the most commonly used and available antibiotics in the country. While the antibiotic to which it was most susceptible of the commonly used antibiotics was trimethoprim/sulfamethoxazole, the antibiotics to which it was least susceptible or most resistant to were ampicillin and penicillin. S. aureus isolates from the pediatric ward produced the greatest rate of susceptibility among the isolates recovered from patients admitted into hospitals, while isolates from Accident and Emergency rooms displayed the greatest susceptibilities among patients from the community. S. aureus isolates from the country did not harbor acquired resistant genes targeting clindamycin/macrolides (ermB), linezolid (cfr) or vancomycin (vanA). The blaZ gene, which is the most common beta lactam (Penicillinase) resistance mechanism for S. aureus, was observed in 88.7% of the methicillin susceptible S. aureus, while methicillin resistance mediated by the mec gene was present in 13.6%. Most of the resistance markers found in MRSA isolates were significantly associated with the ST239-MRSA-III strain in this study, and all isolates that belonged to the USA300 strain, which additionally encoded both the PVL gene and ACME cluster, belonged to CC8. Several resistant genes, such as vanA, cfr and ermB, mediating resistance in S. aureus, are currently non-existent in Trinidad and Tobago. However, the majority of SCCmec genes were observed, suggesting that there is ongoing nosocomial transmission with minimal community transmission. This calls for stringent antibiotic stewardship and policies in the country.

Molecular Analysis of Vancomycin-Resistant Enterococci Isolated from Regional Hospitals in Trinidad and Tobago.

Geographic spread of vancomycin-resistant enterococci (VRE) clones in cities, countries, or even continents has been identified by molecular techniques. This study aimed at characterizing virulent genes and determining genetic relatedness of 45 VRE isolates from Trinidad and Tobago using molecular tools, including polymerase chain reaction, pulsed-field gel electrophoresis (PFGE), and Random Amplification Polymorphic DNA (RAPD). The majority (84%) of the isolates were Enterococcus faecium possessing vanA gene while the rest (16%) were Enterococcus faecalis possessing vanB. The esp gene was found in all 45 VRE isolates while hyl genes were found only in E. faecium species. The E. faecium species expressed five distinct PFGE patterns. The predominant clones with similar or common patterns belonged to clones one and three, and each had 11 (29%) of the VRE isolates. Plasmid content was identified in representative isolates from each clonal group. By contrast, the E. faecalis species had one PFGE pattern suggesting the presence of an occult and limited clonal spread. The emergence of VRE in the country seems to be related to intra/interhospital dissemination of an epidemic clone carrying the vanA element. Therefore, infection control measures will be warranted to prevent any potential outbreak and spread of VRE in the country.

Finer characterization of Mycobacterium tuberculosis using spoligotyping and 15-loci MIRU-VNTRs reveals phylogeographical specificities of isolates circulating in Guyana and Suriname.

In this study we used spoligotyping and 15-loci MIRU-VNTRs for a finer characterization of Mycobacterium tuberculosis strains isolated from patients residing in Guyana (n=74) and Suriname (n=80). The mean age of the patients was 38.5years (36.5 and 40.2years for Guyana vs. Suriname), with a male-to-female sex-ratio of 2.25 for Guyana vs. 4.27 in Suriname. Spoligotyping and 15-loci MIRU-VNTRs led to a total of 41 and 65 different patterns respectively, with an overall clustering rate of 83.8% vs. 68.8%. Combined spoligotyping and VNTR analysis led to the detection of 18 clusters of 2-41 isolates, with an overall clustering of 67.5% and a recent "n-1" transmission rate of 55.8%. Importantly, Guyana was characterized by a significantly higher percentage of clustered isolates than Suriname (79.7% vs. 56.3%; p=0.0019). Three big spoligo/MIRU (SIT/MIT) clusters containing >10 isolates each were shared between the 2 countries, and concerned: T1 sublineage cluster 53/861 (n=41, 37 in Guyana vs. 4 in Suriname); EAI6-BGD1 sublineage cluster 1340/860 (n=16, 3 in Guyana vs. 13 in Suriname); and T1 sublineage cluster 131/146 (n=11, 6 in Guyana vs. 5 in Suriname); as well as 2 smaller clusters of 2 and 3 isolates respectively. However, the relative phylogeographical specificities of strains in circulation as well as a lack of drug-resistance observed among strains from Suriname suggested that trans-border transmission of drug-resistant isolates occurred less frequently than thought. Tracing and interrupting transmission channels of a specific clone (SIT53/15-MIT861) should become a priority in Guyana, not only because it is by far most abundant but also because it accounts for almost half of the drug resistant isolates (n=8/17, 47.1%) in our study, and clustered 5/12 (41.7%) MDR isolates.

A first assessment of Mycobacterium tuberculosis genetic diversity and drug-resistance patterns in twelve Caribbean territories.

With the exception of some French-speaking islands, data on tuberculosis (TB) in the Caribbean are scarce. In this study, we report a first assessment of genetic diversity of a convenience sample of Mycobacterium tuberculosis strains received from twelve Caribbean territories by spoligotyping and describe their drug-resistance patterns. Of the 480 isolates, 40 (8.3%) isolates showed resistance to at least one anti-TB drug. The proportion of drug-resistant strains was significantly higher in The Bahamas (21.4%; P = 0.02), and Guyana (27.5%; P < 0.0001), while it was significantly lower in Jamaica (2.4%; P = 0.03) than in other countries of the present study. Regarding genetic diversity, 104 distinct spoligotype patterns were observed: 49 corresponded to clustered strains (2 to 93 strains per cluster), while 55 remained unclustered among which 16 patterns were not reported previously. Combining the study results with regional data retrieved from the international SITVIT2 database underlined a connection between frequency of certain M. tuberculosis phylogenetic lineages and the language spoken, suggesting historical (colonial) and ongoing links (trade, tourism, and migratory flows) with European countries with which they shared a common past.

Major West Indies MRSA clones in human beings: do they travel with their hosts?

BACKGROUND: Descriptions of the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) have seldom been produced in the Caribbean, which is a major tourism destination. MATERIALS AND METHODS: Using DNA microarrays and spa typing, we characterized 85 MRSA isolates from human skin and soft-tissue infections from five different islands. RESULTS: In the French West Indies (n = 72), the most frequently isolated clones were the same clones that are specifically isolated from mainland France [Lyon (n = 35) and Geraldine (n = 11) clones], whereas the clones that were most frequently isolated from the other islands (n = 13) corresponded with clones that have a worldwide endemic spread [Vienna/Hungarian/Brazilian (n = 5), Panton Valentine leukocidin-positive USA300 (n = 4), New York/Japan (n = 2), and pediatric (n = 1) clones]. CONCLUSION: The distribution of the major MRSA clones in the French (Guadeloupe and Martinique) and non-French West Indies (Jamaica, Trinidad, and Tobago) is different, and the clones most closely resemble those found in the home countries of the travelers who visit the islands most frequently. The distribution might be affected by tourist migration, which is specific to each island.

Human papillomavirus genotypes and their prevalence in a cohort of women in Trinidad.

OBJECTIVE: Human papillomavirus (HPV) genotypes and their relative prevalences were determined in a cohort of 310 sexually active women in Trinidad, West Indies. METHODS: Cervical samples were collected with Ayre's spatulas and endocervical brushes. Samples were used for the conventional Papanicolaou test and for determining HPV genotypes by amplification of a section of the viral L1 gene, followed by DNA sequencing and probe hybridization. RESULTS: HPV infections were identified in 126 of 310 (40.6%) women. Of them, 83 (65.8%) were infected with high-risk HPV, 16 (12.7%) with low-risk HPV, and 27 (21.4%) with HPV types of unknown risk. HPV 52 (12.7%) was the most frequently occurring high-risk type, followed by HPV 66 (10.3%), HPV 16 (9.5%), and HPV 18 (8.6%). High-risk types HPV 16 and HPV 66 were each found in 3 (20.0%) and HPV 18 was found in 1 (6.6%) of the 15 women with abnormal cytology. CONCLUSIONS: Cervical HPV prevalence and heterogeneity of HPV genotypes are high in this Trinidad cohort. The relative importance of HPV genotypes in the development of cervical lesions needs further investigation in Trinidad in order to better understand the epidemiology of HPV infections as well as to determine the role of HPV testing in the screening, prevention, and control of cervical cancer. This pilot study provided important information on the prevalence of HPV genotypes, which will be used in future nationwide studies.

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.

Human papillomavirus genotypes and their prevalence in a cohort of women in Trinidad / Genotipos del papilomavirus humano y su prevalencia en una cohorte de mujeres en Trinidad

OBJECTIVE: Human papillomavirus (HPV) genotypes and their relative prevalences were determined in a cohort of 310 sexually active women in Trinidad, West Indies. METHODS: Cervical samples were collected with Ayre's spatulas and endocervical brushes. Samples were used for the conventional Papanicolaou test and for determining HPV genotypes by amplification of a section of the viral L1 gene, followed by DNA sequencing and probe hybridization. RESULTS: HPV infections were identified in 126 of 310 (40.6 percent) women. Of them, 83 (65.8 percent) were infected with high-risk HPV, 16 (12.7 percent) with low-risk HPV, and 27 (21.4 percent) with HPV types of unknown risk. HPV 52 (12.7 percent) was the most frequently occurring high-risk type, followed by HPV 66 (10.3 percent), HPV 16 (9.5 percent), and HPV 18 (8.6 percent). High-risk types HPV 16 and HPV 66 were each found in 3 (20.0 percent) and HPV 18 was found in 1 (6.6 percent) of the 15 women with abnormal cytology. CONCLUSIONS: Cervical HPV prevalence and heterogeneity of HPV genotypes are high in this Trinidad cohort. The relative importance of HPV genotypes in the development of cervical lesions needs further investigation in Trinidad in order to better understand the epidemiology of HPV infections as well as to determine the role of HPV testing in the screening, prevention, and control of cervical cancer. This pilot study provided important information on the prevalence of HPV genotypes, which will be used in future nationwide studies.

OBJETIVO: Se determinaron los genotipos del papilomavirus humano (PVH) y su prevalencia relativa en una cohorte de 310 mujeres sexualmente activas de Trinidad, en la zona de las Indias Occidentales. MÉTODOS: Se tomaron muestras del cuello uterino con espátula de Ayre y cepillo endocervical. Las muestras se usaron para llevar a cabo la prueba convencional de Papanicolaou y para determinar los genotipos de PVH mediante la amplificación de una sección del gen vírico L1, seguida de secuenciación del ADN e hibridación con sonda. RESULTADOS: Se encontró una infección por PVH en 126 de las 310 mujeres (40,6 por ciento). De ellas, 83 (65,8 por ciento) estaban infectadas con PVH de alto riesgo, 16 (12,7 por ciento) con PVH de bajo riesgo, y 27 (21,4 por ciento) con tipos de PVH de riesgo desconocido. De los PVH de alto riesgo, el más frecuente fue el PVH 52 (12,7 por ciento), seguido por el PVH 66 (10,3 por ciento), el PVH 16 (9,5 por ciento) y el PVH 18 (8,6 por ciento). Entre las 15 mujeres con citología anormal se encontraron los PVH de alto riesgo 16 y 66 en 3 (20,0 por ciento) mujeres cada uno, y el PVH 18 en 1 (6,6 por ciento). CONCLUSIONES: Tanto la prevalencia de PVH en el cuello uterino como la heterogeneidad de los genotipos de PVH son elevadas en esta cohorte de Trinidad. La importancia relativa de los genotipos de PVH en la aparición de las lesiones cervicales requiere de mayor investigación en Trinidad para conocer más a fondo las características epidemiológicas de las infecciones por PVH, así como para determinar el papel del estudio de los PVH en la detección sistemática, la prevención y el control del cáncer del cuello uterino. Este estudio piloto suministró información importante sobre la prevalencia de los genotipos de PVH, que se usará en futuros estudios que se lleven a cabo en todo el país.

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.

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.