Escherichia coli contamination of lettuce sold at markets in Trinidad: A preliminary study

Objective: Historically most foodborne disease outbreaks have been attributed to animal products but recently the number of cases associated with vegetable produce has been increasing. Most of these microbial foodborne pathogens are also part of the resident gut flora of many animals and can be shed asymptomatically in the environment. Leafy greens contamination with these pathogens are of particular concern since they are consumed uncooked. Using Escherichia coli (E. coli) as an indicator of faecal contamination, we evaluated lettuce as a potential source of foodborne disease. Design and Methodology: A cross-sectional study was carried out targeting six retail markets in Trinidad. At each market, a total of 15 lettuce samples were purchased from five retailers. The E. coli colony forming units per gram (CFU/g) of lettuce were then assessed using standard laboratory techniques. Results: All farmers surveyed reported using pipe-borne water as their primary source of irrigation water. E. coli was present in all samples. Overall, the E. coli counts ranged from 0.8 to 80,000 CFU/gram. The lettuce E. coli counts varied with location (p=0.01) and was highest in San Fernando (3.4 ± 1.1 Log10CFU/g) and lowest in Marabella (1.5 ± 0.65 Log10 CFU/g). Interestingly, lettuce farms using manure had lower E. coli counts than those not using manure (2.88 ± 1.3 Log10 CFU/g vs 2.27±1.23 Log10 CFU/g; p=0.07.) Conclusion: These high E.coli counts are indicative of either preharvest or post-harvest faecal contamination of lettuce. The high level of E. coli contamination of lettuce being sold at market should be of serious concern since this a potential risk to public health.

Prevalence of Methicillin-resistant Staphylococcus aureus in the Surgical Wards of the Port-of-Spain General Hospital, Trinidad and Tobago / Prevalencia del estafilococo dorado resistente a la meticilina en las salas quirúrgicas del Hospital General de Puerto España, Trinidad y Tobago

ABSTRACT Objective: Methicillin-resistant Staphylococcus aureus (MRSA) is associated with soft tissue infections in surgical patients. In severe cases, it may result in pneumonia, septicaemia and osteomyelitis. Limited data are available with regard to its prevalence and associations in the Caribbean. This study aimed to assess the prevalence of MRSA in patients hospitalized in the surgical wards of the Port-of-Spain General Hospital (POSGH), Trinidad and Tobago, and determine associated risk factors. Methods: Over the period of April 1 to August 1, 2013, all patients from the surgical wards of the POSGH who had had wound swabs taken were identified. Demographic data included duration of hospital stay, surgical and medical history, antibiotic use and type of wound swab. Microbiological reports were then retrieved and analyses done. Results: A total of 153 patients had wound swabs taken. There were 38 patients (24%) infected with Staphylococcus aureus, with 15 (39.5%) growing MRSA. Increased susceptibility to MRSA was associated with age, gender, ethnicity, duration of hospital stay, co-morbidities, previous antibiotic use, previous surgery and the type of wound (p < 0.05). Conclusion: The prevalence of MRSA in the surgical wards of the POSGH was 39.5% of Staphylococcus aureus isolates. Risk factors included the age range of 60-69 years, patients with co-morbidities, hospital stays of longer than one week, previous surgery and prior use of antibiotics. We recommend more awareness of this problem in the practice of Caribbean medicine to improve infection rates.

RESUMEN Objetivo: El estafilococo dorado resistente a la meticilina (EDRM) se asocia con infecciones de tejidos blandos en pacientes quirúrgicos. En casos severos, puede dar lugar a pulmonía, septicemia y osteomielitis. Los datos disponibles con respecto a su prevalencia y asociaciones en el Caribe son limitados. Este estudio persigue evaluar la prevalencia de EDRM en pacientes hospitalizados en las salas quirúrgicas del Hospital General de Puerto de España (POSGH, siglas en inglés) en Trinidad y Tobago, y determinar los factores de riesgo asociados. Métodos: Durante el período del 1 de abril al 1 de agosto de 2013, fueron identificados todos los pacientes de las salas quirúrgicas del Hospital POSGH a quienes se les había practicado frotis de las heridas. Los datos demográficos incluyeron la duración de la estadía hospitalaria, las historias clínicas y quirúrgicas, el uso de antibióticos, y el tipo de frotis de la herida. Luego se obtuvieron los informes microbiológicos y se realizaron los análisis. Resultados: A un total de 153 pacientes se le tomaron frotis de heridas. Hubo 38 pacientes (24%) infectados con estafilococos dorados, de los cuales 15 (3.5%) presentaban EDRM creciente. El aumento de la susceptibilidad a EDRM se asoció con la edad, el género, la etnicidad, la duración de la estadía hospitalaria, las co-morbilidades, el uso previo de antibióticos, las cirugías previas, y el tipo de herida (p < 0.05). Conclusión: La prevalencia de EDRM en las salas quirúrgicas del Hospital POSGH fue 39.5% de aislados de estafilococos dorados. Los factores de riesgo incluyeron un rango de edad de 60-69 años, pacientes con co-morbilidades, estancia hospitalaria de más de una semana, cirugía previa, y uso previo de antibióticos. Recomendamos tomar más conciencia de este problema en la práctica médica en el Caribe a fin de mejorar las tasas de infección.