SUITABILITY OF VITEK 2 SYSTEM IN IDENTIFICATION AND SUSCEPTIBILITY TESTING OF GRAM NEGATIVE BACTEREMIAS BY DIRECT INOCULATION

OBJECTIVE

To verify the accuracy of direct Vitek testing for blood cultures with Gram-negative bacilli.

DESIGN

Validation study.

SETTING

Aga Khan University Hospital Nairobi.

SUBJECTS

Twenty two positive blood cultures.

MAIN OUTCOME MEASURES

Correct bacteria identification and errors for susceptibility testing.

RESULTS

Of the 22 samples analysed 19 (86%) were correctly identified by direct Vitek testing and three (14%) were unidentified. Of the three, one had mixed growth and the other two had pure growth on sub-cultures. Of the 19 cultures with antimicrobial susceptibility testing by direct Vitek, three had discrepancies for some antibiotics when compared with the conventional Vitek method. These discrepancies were minor errors that would not have had any clinical impact.

CONCLUSION

These data suggest that direct Vitek would provide acceptable identification and antimicrobial susceptibility testing results for Gram-negative bacilli. Compared to the standard method, the direct Vitek method would reduce turnaround time by at least twelve to twenty four hours.

A FIVE YEAR REVIEW OF API20E BACTERIA IDENTIFICATION SYSTEM'S PERFORMANCE AT A TEACHING HOSPITAL

OBJECTIVES

To assess the performance of the API20E bacteria identification system at a teaching hospital in Kenya.

DESIGN

Retrospective study.

SETTING

The microbiology laboratoryoratory of the Aga Khan University teaching Hospital.

SUBJECTS

One thousand six hundred and fifty eight API20E records.

MAIN OUTCOME MEASURES

The accuracy in identifying the bacteria species.

RESULTS

One thousand four hundred and forty two (87.6%) isolates had the exact identity, 199 (12%) nearest identity, and seven (0.4%) no identity. The performance varied among the species; Acinetobacter baumanii had 140 (99.3%) isolates with the exact identity and only one (0.7%) with the nearest identity compared with Aeromonas hydrophila which had five (17.2%) with exact and 24 (82.8%) with nearest.

CONCLUSIONS

The API20E system is a robust bacteria identification method which can serve small and medium clinical microbiology laboratories that may not afford automated systems. Adhering to the manufacturer's instructions and good.

[Oligodontia. A case report]

"Oligodontia" is the absence of 6 or more teeth, except the third molars. Genetic factors are important in determining hypodontia: in fact, this is an autosomal dominant trait relatively common in population. In particular, the agenesis of lateral incisors is fairly common, with autosomal dominant and variable expression inheritance. The incidence of hypodontia in primary dentition is 0.1-0.7% and there is no difference between females and males; instead, hypodontia in permanent dentition is most common in females compared with males and the incidence is 6-10% in general population. Oligodontia can interfere with the maxillofacial skeleton growth in children and adolescents. This problem must be tackled by paying attention to the physical and psychological development of the patient. A case of oligodontia in an 8-year-old-boy without 17 permanent teeth likely related to a variable expression genetic disorder is reported. The medical examination of the boy was completely negative, with the exception of the dentition. The child will be followed to value any possible maxillofacial abnormalities that might need an early therapy. The definitive therapeutic approach will be carried out, as soon as possible, using oral endo-osseous systems to allow normal masticatory and phonetic function.

Scent of a Ewe: transmission of a social cue by conspecifics affects sexual performance in male sheep

Unlike males from other domestic species, domestic rams (Ovis aries) are not sexually stimulated, as determined by measuring sexual performance, following the opportunity to watch a copulating pair. Previously, we reported that aspects of ram sexual performance were improved when rams interacted with a male conspecific that had mated an estrous ewe. Whether the cues were gender-, estrous state-, or behavior-related was tested in this study. Sexually experienced rams were exposed to male pen mates that had interacted with an estrous ewe, a non-estrous ewe, an estrous ewe with a cloth perineal patch, or a ram, or that had been placed alone in a small pen. The rams were then tested for sexual performance. Rams performed more olfactory investigative behaviors toward pen mates that had interacted with a ewe, regardless of her estrous state, than toward a pen mate that had been exposed to another male. Rams exposed to pen mates that had interacted with a ewe also had shorter postejaculatory and interejaculation intervals and subsequently achieved more ejaculations in standardized sexual performance tests. Results from this experiment confirm that male-male interactions affect sexual performance in male sheep and that olfactory cues likely account for the transfer of information among individuals.

[Thyroid function in children with Down's syndrome]

The aim of the present study was to evaluate thyroid function in 45 Down's syndrome patients in order to verify the hypothesis of an increased risk of thyroid disorders associated with trisomy 21. A patient with subclinical hypothyroidism (TSH 16.6 microU/ml; T4 6.4 micrograms/dl) was diagnosed in a group of 28 subjects with Down's syndrome studied at a mean age of 6 years and 5 months using T3, T4, FT3, FT4, TSH assays and clinical examination. T4 and TSH values were also measured in 10 of these children at the neonatal screening. One infant presented transient neonatal hyperthyrotropinemia but later became euthyroid. The analysis of thyroid hormone values at the neonatal screening of other 17 subjects with Down's syndrome did not reveal other cases with thyroid function disorders. The results of this study highlight that altered thyroid functions are evident in children with trisomy 21 associated with heart anomalies. A careful clinico-endocrinological follow-up of patients with Down's syndrome is recommended in order to ensure an early diagnosis of thyroid function disorders and/or autoimmune diseases which might complicate the evolution of trisomy and negatively affect outcome.

[Cholesterol screening in a pediatric population at atherosclerotic risk]

We studied 344 children (174 girls and 170 boys) between the ages of 6 and 15 years (average age 11 years 9 months) chosen on the basis of a positive family anamnesis for dismetabolic and/or precocious cardiovascular pathologies, and also on the basis of objective data obtained at medical examinations, such as obesity and hypertension. These subjects underwent blood tests for glycaemia, total cholesterol, HDL cholesterol, LDL cholesterol and triglycerides. Children with total cholesterol levels above 170 mg/dl were considered to be hypercholesterolemic. 127 young people (65 girls and 62 boys) turned out to have excessively high cholesterol levels with an average level of 195.71 +/- 23.11 mg/dl and average LDL level of 127.05 +/- 25.08 mg/dl. 217 subjects (109 girls and 108 boys) turned out to be within the norm with total cholesterol level of 137.76 +/- 23.04 mg/dl and LDL cholesterol 75.59 +/- 22.89 mg/dl. We found a greater difference between the average values of LDL cholesterol and those of total cholesterol (40.5% compared to 29.61%), which shows that even at pediatric ages the LDL cholesterol concentration is the factor which best indicates the risk level for atherosclerotic development.

[Selenium in the full-term and premature newborn infant]

The following observations can be made on the basis of findings relating to selenium in serum samples taken from 55 neonates (35 born at term and 20 born pre-term): 1) the blood concentration of selenium in neonates born at term showed no substantial difference to that reported by other authors; moreover, there were no sex or birthweight-dependent variations, and no correlations were found with either the mother's age or the mode of engendering procreation; 2) the blood concentration of selenium in neonates born pre-term was 30% lower than that found in neonates born at term; it was correlated with gestational age and birthweight, but not with sex, mother's age or the mode of engendering procreation. It will be worthwhile continuing these tests in order to identify possible therapeutic uses of selenium in cases of deficiency.

[Carnitine and Down's syndrome]

The present study revealed a degree of carnitine deficiency in a large percentage of Down's syndrome children. In fact below average carnitine levels were noted in 39.1% of the cases examined with severe deficiency in 4. On the basis of these data supplementary carnitine is recommended in cases of deficiency particularly in view of the value of carnitine in the prevention of cell aging.

[Vitamin C in children with trisomy 21]

The present study revealed ascorbic acid deficiency in the blood of many children with Down's syndrome. It also revealed a fairly definite connection between Vitamin C deficiency and diet in these patients and a similar link between ascorbic acid deficiency and this incidence of infections. Where necessary the prescription of Vitamin C for the prevention and treatment of recurring infection is therefore recommended, bearing in mind the valuable antioxidant properties of ascorbic acid that can be exploited in combating cell deterioration.

[Blood zinc in patients with Down's syndrome and its relations with their immune status]

Studies performed in the last decade have shown the importance of zinc in human physiology particularly in cell mediated immunity. Blood zinc values were assayed with the atomic absorption method using a Perkin/Elmer 2.380 spectrophotometer in 35 Down's syndrome subjects (DS) (16 boys and 19 girls aged 6 months 20 years) and in normal subjects in good health. The immunological picture was determined as previously described. Zinc values in normal subjects were in the range 92-128 micrograms/dl (mean value 107 +/- 10.46 micrograms/dl). The values are in the normal range. The range of blood zinc values of DS children was 60-138 micrograms/dl (mean value 92.22 +/- 19.76 micrograms/dl). Of the 35 subjects with DS, 16 had values of 60-84 micrograms/dl (mean 74.25 +/- 8.29 micrograms/dl) (table I), which are well below normal. Blood zinc values were not correlated to age and sex. A relationship was found with mortality. Out of 16 patients with low zinc values 10 (68.5%) were particularly susceptible to infections. These data were then related to results concerning the immunological status of a previous study. The only three negative skin tests were observed in subjects with low blood zinc. 62.5% of DS subjects with low blood zinc also had a complete lymphocyte deficit (table I) as compared to 42.1% of DS cases with normal zinc levels. Respectively 56.25% and 36.8% of DS cases with low blood zinc values had an abnormal and normal T helper/T suppressor ratio. Only 3 (8.57% of all cases and 18.75% of low blood zinc values) subjects had an alteration of all the parameter evaluated (including morbility).(ABSTRACT TRUNCATED AT 250 WORDS)

[The immunological profile of children with Down's syndrome]

In 1965 Benda demonstrated that bioptic and autoptic material of children with Down's syndrome showed hypoplasia of the thymus with poor histological differentiation between the cortex and medulla and impairment of Hassal's corpuscles which were also fewer than normal. In the seventies studies revealed the increased susceptibility to infections and higher incidence of leucosis in Down's syndrome patients as well as changes of immunologic defences (in particular cell mediated immunity). This study examines 35 children (16 boys and 19 girls) aged 6 months-20 years. Subjects were divided into a group of 18 cases in poor health with a history of recurrent infections and a group of 17 children in good health. Skin tests were performed by inoculating 0.1 ml of a solution formed by 1 ml physiological solution and 0.1 ml tetanus toxoid. Skin reaction was evaluated 48 hours later. Lymphocyte typing tests were performed with the rosette method and with monoclonal antibodies for T lymphocytes and with the determination of surface immunoglobulins for B lymphocytes. OKT4 (T helper), OKT8 (T suppressor) subsets assayed and the OKT4/OKT8 ratio was determined. Skin tests were negative in 3 cases (8.6%). The number of B lymphocytes was normal in all children. Total number of lymphocytes was decreased in 51.4% of cases. Two subjects had a reduction of OKT4 and 14 had an increased of OKT8 and 16 a significantly lower OKT4/OKT8 ratio. It is clear that skin tests were normal also in those children with low total lymphocyte values. The most closely related parameter to mobility was the OKT4/OKT8 ratio and the most distantly related on was the skin test. Only 3 cases had modifications of all 3 parameters together. Apart from the constant and complete immunological deficit described by many authors and which we cannot confirm the results of this study are in agreement with those of other authors.