Evaluation of reagent strips in detecting asymptomatic bacteriuria in early pregnancy: prospective case series.

OBJECTIVE: To evaluate the performance of reagent test strips in screening pregnant women for asymptomatic bacteriuria at their first visit to an antenatal clinic. DESIGN: Prospective case series. SETTING: Antenatal clinic of a large inner city maternity hospital. SUBJECTS: All women attending for their first antenatal clinic. Patients taking antibiotics for any reason and those with urinary tract symptoms were excluded. INTERVENTION: A midstream urine specimen was divided; half was sent for microscopy and formal bacteriological culture and the other half was tested with a commercial reagent strip test for the presence of blood, protein, nitrite, and leucocyte esterase. MAIN OUTCOME MEASURES: Sensitivity, specificity, and positive and negative predictive values of the reagent strips in diagnosing asymptomatic bacteriuria (defined as 10(5) colony forming units/ml urine). RESULTS: Sensitivity was low, with a maximum of 33% when all four tests were used in combination. Specificity was high, with typical values of 99% or more. Positive predictive value reached a maximum of 69% and negative predictive value was typically 95% or more. CONCLUSION: Urine reagent strips are not sufficiently sensitive to be of use in the screening for asymptomatic bacteriuria and therefore many patients would be missed. In view of the potentially serious sequelae of this condition in pregnant women we recommend that formal bacteriological investigation remain the investigation of choice in this group of patients.     

Characterization of the variable-number tandem repeats in vrrA from different Bacillus anthracis isolates.

PCR analysis of 198 Bacillus anthracis isolates revealed a variable region of DNA sequence differing in length among the isolates. Five polymorphisms differed by the presence of two to six copies of the 12-bp tandem repeat 5'-CAATATCAACAA-3'. This variable-number tandem repeat (VNTR) region is located within a larger sequence containing one complete open reading frame that encodes a putative 30-kDa protein. Length variation did not change the reading frame of the encoded protein and only changed the copy number of a 4-amino-acid sequence (QYQQ) from 2 to 6. The structure of the VNTR region suggests that these multiple repeats are generated by recombination or polymerase slippage. Protein structures predicted from the reverse-translated DNA sequence suggest that any structural changes in the encoded protein are confined to the region encoded by the VNTR sequence. Copy number differences in the VNTR region were used to define five different B. anthracis alleles. Characterization of 198 isolates revealed allele frequencies of 6.1, 17.7, 59.6, 5.6, and 11.1% sequentially from shorter to longer alleles. The high degree of polymorphism in the VNTR region provides a criterion for assigning isolates to five allelic categories. There is a correlation between categories and geographic distribution. Such molecular markers can be used to monitor the epidemiology of anthrax outbreaks in domestic and native herbivore populations.     

NEW INTERGENOMIC HYBRIDS AMONG SOME AFRICAN DIPLOID SPECIES OF HIBISCUS SECT. FURCARIA

Chromosome pairing was examined at Metaphase 1 in F₁ hybrids between Hibiscus surattensis L. (B genome) and three other diploid species, H. hiernianus Exell, H. mastersianus Hiern, and H. mechowii Garcke. The low level of chromosome association in all three types of hybrids indicated that the pollen parent of each hybrid contributed a genome that was meiotically nonhomologous with B. Earlier studies had shown that H. mastersianus and H. hiernianus have similar genomes that are nonhomologous with the genome of H. mechowii. Thus, these four African diploids with overlapping ranges encompass three different genome groups. Provisional genome designations were assigned as follows: H. hiernianus, X_hie; H. mastersianus, X_mas; H. mechowii, Y_mec.