Coagulase negative Staphylococci from blood cultures: contaminants or pathogens? / Estafilococos Coagulasa-Negativos de Cultivos de Sangre: ¿Contaminantes o Patógenos?

Detailed clinical data, underlying conditions, inflammatory indices and microbiological parameters in 60 patients who had pure growth of coagulase negative staphylococci from their blood culture specimens at the University Hospital of the West Indies, Jamaica, were analyzed and the clinical significance of the isolates ascertained using standard criteria. This study was undertaken between April and September 2003. The isolates were true pathogens of bloodstream infections in only 5 of the 60 patients (8.4). In the vast majority ie 44 of 60 (73.3) they were mere blood culture contaminants and in 11 (18.3), the clinical significance could not be ascertained Fifteen of the 44 patients (34) with contaminating coagulase negative staphylococci were treated with specific anti-staphylococcal antibiotics; 5 (11.4) with vancomycin. Although there has been a relative increase of coagulase negative staphylococcal infections including bloodstream infections in recent years, the organisms still remain the most common contaminants in blood cultures. Over 70of isolates were contaminants in this study which is similar to that in a number of such studies in other parts of the world The findings underline the need for careful evaluation of coagulase negative staphylococci isolated from blood cultures before instituting therapy to avoid unnecessary use of antibiotics, especially vancomycin, and the consequent increase of antibiotic resistance in hospitals.

Los datos clínicos detallados, las condiciones subyacentes, los índices inflamatorios así como los parámetros microbiológicos de 60 pacientes que presentaron crecimiento puro de estafilococos coagu-lasa-negativos de sus cultivos de sangre en el Hospital Universitario de West Indies, Jamaica, fueron sometidos a análisis. De este modo, se pudo determinar la significación clínica de los aislados, usando criterios estándar. En sólo 5 de los 60 pacientes (8.4%), los aislados resultaron ser realmente pató-genos de infecciones del torrente sanguíneo. En la gran mayoría, a saber 44 de 60 (73.3%), se trataba tan sólo de contaminantes en el cultivo de la sangre, y en 11 (18.3%) no pudo determinarse la impor-tancia clínica. Quince de los 44 pacientes (34%) con estafilococos coagulasa-negativos contaminantes, fueron tratados con antibióticos antiestafilocócicos específicos, y 5 (11.4%) con vancomicina. Aunque en años recientes ha habido un aumento relativo de infecciones por estafilococos coagulasa-negativos – incluyendo infecciones del torrente sanguíneo – los organismos siguen siendo todavía los contamin-antes más comunes en los cultivos de sangre. Más del 70% de los aislados resultaron ser contaminantes en este estudio: un resultado similar al obtenido en una serie de estudios de este tipo realizado en otras partes del mundo. Los hallazgos apuntan a la necesidad de realizar una evaluación cuidadosa de los estreptococos coagulasa-negativos aislados en los cultivos de sangre antes de proceder a instituir la terapia, a fin de evitar el uso innecesario de antibióticos – en especial la vancomicina – y el consiguiente aumento de la resistencia antibiótica en los hospitales.

Epidemiology of coagulase-negative Staphylococci isolated from clinical blood specimens at the University Hospital of the West Indies / Epidemiología de los Estafilococos Coagulasa Negativos Aislados de Especímenes Clínicos de Sangre en el Hospital Universitario de West Indies

The prevalence and significance of coagulase negative staphylococci (CoNS) isolated from blood cultures at the University Hospital of the West Indies (UHWI) during a six-month period were investigated. Standard and automated microbiological procedures were used to process 3001 blood culture specimens received from 2363 patients and 658 (21.9) of the blood cultures yielded 854 bacterial isolates. The highest prevalence of positive blood cultures (60) and the lowest prevalence of blood isolates of CoNS (12) were found in the intensive care unit (ICU). The blood isolates of CoNS were most frequent in the surgical wards (13) and lowest in obstetrics and gynaecology (2). High rates of resistance to methicillin, other anti-staphylococcal penicillins, and cephalosporins used in the treatment of CoNS were observed All blood isolates of CoNS (100) were susceptible to vancomycin. In conclusion, the results show that coagulase-negative staphylococci are the most prevalent bacterial isolates in blood cultures at the UHWI occurring mostly as contaminants. The practice of proper venepuncture and hand-washing techniques by medical staff are recommended to facilitate appropriate antibiotic usage.

Se investigó la prevalencia e importancia de los estafilococos coagulasa negativos (ECoN) aislados de cultivos de sangre en el Hospital Universitario de West Indies (HUWI) por un período de seis meses. Se utilizaron procedimientos microbiológicos estándar y automatizados para procesas 3001 cultivos de sangre recibidos de 2363 pacientes y 658 (21.9%) de los cultivos dieron 854 aislados bacterianos. La más alta prevalencia de cultivos de sangre positivos (60%) y la más baja prevalencia de aislados de ECoN (12%) se encontraron en la Unidad de Cuidados Intensivos (UCI). Los aislados de sangre de ECoN fueron más frecuentes en las salas de cirugía (13%) y más bajos en las de obstetricia y ginecología (2%). Se observaron altas tasas de resistencia a la meticilina, así como a otras penicilinas anti-estafilocócicas y cefalosporinas usadas en el tratamiento de ECoN. Todos los aislados de sangre de ECoN (100%) fueron susceptibles a la vancomicina. En conclusión, los resultados muestran que los estafilococos coagulasa negativos son los aislados bacterianos más prevalentes en cultivos de sangre en el HUWI, presentándose en la mayor parte de los casos como contaminantes. Se recomienda la práctica de técnicas adecuadas de venepuntura y lavado de manos por parte del personal médico a fin de facilitar un uso antibiótico correcto.

Decrease in the incidence of tetracycline resistance in strains of Neisseria gonorrhoeae in the nineties

Antibiotic resistance determined by standard disc-diffusion method on GC agar with supplement B in 583 strains of Neisseria gonorrhoeae encountered between 1991 and 1996 at the University Hospital of the West Indies, Kingston, Jamaica, were analyzed. The level of penicillin resistance varied between 40 and 28 over the years. Tetracycline resistance fell from 44.2 in 1991 to 23.9 in 1996. Twenty-one per cent of the isolates were resistant simultaneously to both penicillin and tetracycline in 1991. The percentage of such strains decreased to 6.5 in 1996. Ceftriaxone was introduced as a first line drug in treatment of gonococcal infections in the late 1980s. The declining trend of tetracycline resistance may be due to a decrease in the usage of tetracycline in recent years

Hepatic abscesses at the University Hospital of the West Indies. A 24-year autopsy review

A retrospective review of all hepatic abscesses identified at autopsy over the 24-year period 1977-2000 at the University Hospital of the West Indies (UHWI), Kingston, Jamaica, was conducted. Post mortem and microbiology records were reviewed. Data collected included age, gender, predisposing factors, organisms isolated, number of abscesses and associated conditions, such as diabetes mellitus. Data for the adults was analyzed separately. Thirty-nine cases of pyogenic abscesses were identified from 7480 post-mortems. Thirty-three occurred in adults of mean age 59.5 years. Sixty per cent of the abscesses were solitary. Biliary tract disease was the predisposing factor in 33 of cases. Six per cent were cryptogenic: 11/33 patients were diabetic and these were significantly older than non-diabetics (p < 0.014) Klebsiella pneumoniae was the most common organism isolated from diabetics (6.9). Only 2/33 abscesses were diagnosed ante-mortem. The abscesses in children were more frequently multiple and associated with extra-abdominal infection. Gram positive cocci were the commonly isolated organisms in children. There were no cases of amoebic abscess. The prevalence of hepatic abscess was low. Diabetes mellitus was a significant contributing factor. A high index of clinical suspicion is therefore warranted particularly in elderly diabetics

The medical management of diabetes mellitus with particular reference to the lower extremity: the Jamaican experience

Predisposing factors for the diabetic foot include peripheral neuropathy, peripheral vascular disease (PVD), hyperglycaemia and increased duration of diabetes. From the records of patients admitted to the University Hospital of the West Indies with the diabetic foot, we reviewed the results of the microbiology of wound swabs from diabetic foot ulcers. We noted the high prevalence of P VD (66.6), peripheral neuropathy (50), hyperglycaemia (75.6) and increased duration of diabetes (17.5 years). A history of past foot ulcers was common and 87.2had polymicrobial infection. The commonest organisms were gram positive organisms which were usually sensitive to the 2 antibiotic regimes that were commonly used. Euglycaemia, a favourable lipid profile, control of blood pressure, yearly foot examination and institution of measures to prevent foot trauma are important in the prevention of foot ulceration.

Disseminated infection caused by penicillin-resistant gonococci in two jamaicans

Disseminated gonococcal infection due to penicillin-resistant organisms is very unusual. Two such cases occuring at the University Hospital of the West Indies are described. Implications for therapy are discussed