RESUMEN

The aim of the study was to reduce to key tests the 4 extensive polyvalent diagnostic biochemical tables most widely used in Croatia and to adapt them for the demonstration of Vibrio cholerae and its differentiation from the 3 Vibrios (V. alvinolyticus, V. mentschikovii, V. fluvialis) important in differential diagnosis. The fourth table has now been adapted to differentiate among all 12 Vibrio species known to be human pathogens (V. mimicus, V. cincinatiensis, V. holisae, V. damsela, V. furnisi, V. parahaemolyticus, V. vulnificus, V. carchariae). Using the inductive Learning by Logic Minimization Method (ILLM), we analyzed 2 tables (i.e. identification matrices) that were a part of bioMérieux's commercial packaged polyvalent identification systems widely used in Croatia (API 20E and ATB 32E), as well as 2 compilation tables by M. T. Kelly et al. The tables contained 27, 32, 59 and 8 tests, respectively. Cutting these solely to the key tests involved rationalizing them from 59 to the 5 necessary to differentiate Vibrio cholerae from 3 related Vibrios. Further rationalizations were from 32 to 2 and from 27 to the 3 necessary to differentiate Vibrio cholerae from 2 related Vibrios. By reducing the table of 8 tests to 7, and adding 4 new ones to these we achieved an optimization permitting mutual differentiation of all 12 known human Vibrio pathogens. Use of the selective TCBS plating medium was the only precondition for making these tables effective.

Asunto(s)

RESUMEN

Changes in the proportion of VDRL nonreactors among the people who had come into contact with Treponema pallidum in the course of their lifetime were assessed within the frame of the Diagnostic Proficiency Program covering serologic laboratories for the detection of syphilis in Croatia. Based on the analysis of the CNIPH serologic laboratory records the paper shows a clear increase in the above share over the past 22 years. Data on 491 infected persons (those reactive to the reference TPHA test), mean age 52.87 years, were analyzed. During 22 years of observation (1976-1998), this proportion rose from 21.92% (1976-1979) through 51.79% (1980-1989) to 64.86% (1990-1998). At the same time, this tendency reveals a considerable decrease in the number of infected persons exhibiting VDRL reaction (i.e. with potentially active late syphilis), which could be ascribed to the ever more effective detection of the infected and to their ever earlier and more efficient treatment.

Asunto(s)

RESUMEN

BACKGROUND AND OBJECTIVES: Interlaboratory differences (and conflicting practices) in syphilis screening strategies (serial versus parallel test combinations) prompted us to determine an estimate of the diagnostic miss rate in the detection of (1) infected persons and (2) infected but untreated persons potentially affected by late active syphilis. GOAL: We set out to establish the most efficient syphilis screening strategy for two routine tests (VDRL and Treponema pallidum hemagglutination assay [TPHA]) with regard to our tested public health population (average VDRL+ TPHA+ and VDRL- TPHA+ reactor ages being 59.9 years and 50.5 years, respectively. STUDY DESIGN: Retrospective analysis covered the results of a routine parallel VDRL and TPHA testing on 24,863 persons done in four public health laboratories. Nosologic sensitivity of the VDRL test (18.32%) was determined using the TPHA test as reference. The percentage of VDRL nonreactors among infected persons (TPHA reactors) was considered as the VDRL false negative rate (81.68%). We estimated the proportion of persons infected but untreated with potential late active syphilis using our own Bayes theorem-based procedure. RESULTS: The Bayes theorem-based estimate showed a significantly higher value for persons at risk of active late syphilis than the number of suspected cases obtained using the classical approach (25.1% versus 18.32%, or 83 persons versus 61 of the 330 infected). CONCLUSION: In screening an older population, the VDRL test alone (or as the first of a series with TPHA as a confirmation test) may produce a diagnostic miss rate higher than the syphilis detection rate. Another miss in such a population is detected by the Bayes theorem-based method.

Asunto(s)

Asunto(s)

RESUMEN

In this paper a novel computer example-based learning system (Inductive learning by logic minimization) was used to determine the sufficient set of biochemical reactions and necessary conditions that have to be fulfilled for the correct identification of enterococci isolated from human specimens. Several combinations for accurate identification of Enterococcus faecalis and Enterococcus feacium from other enterococci were found. The simplest combination set for E. faecalis identification consists of 3 reactions: growth in 0.04% K-tellurite, mannitol acidification, failure to acidify raffinose. The simplest set for E. faecium differentiation from other enterococcal species is performed by the following 3 reactions: failure to acidify D-xylose and Na-pyruvate, and acidification of L-arabinose. Only 4 tests are sufficient (acid from D-xylose, mannitol, L-arabinose and Na-pyruvate) for the correct identification of these two, the most frequently isolated species. If it is necessary to analyze all enterococcal species, then even three combinations of 9 tests for the correct differentiation of any of them, are available.

Asunto(s)

Asunto(s)

RESUMEN

Microorganisms referred to as Streptococcus anginosus (Streptococcus milleri) group which consist of S. anginosus, S. intermedius and S. constellatus is very difficult to identify to the species level, because of their diversity of biochemical, hemolytic and serological characteristics and because of confusion surrounding their taxonomy. Identification procedures on three isolates from primary sterile sites of three different patients, using API 20A system are described. Streptococcus intermedius was established in two and Streptococcus anginosus in one case. The importance of these organisms as human pathogens should enhance efforts of clinical microbiologist towards their accurate identification.

Asunto(s)

RESUMEN

Some differential growth characteristics for Vibrio cholerae and Vibrio metschnikovii were examined in a liquid medium with reference to pH and ionic strength, as well as temperature and length of incubation. The purpose was to discover the combination of the above conditions which would enable selective replication of V. cholerae accompanied by suppressed growth of V. metschnikovii. Preliminary routine verification of one combination of conditions which involves a lengthening of incubation to 22 h at a heightened temperature of 41 degrees C in sewage water samples pointed to the possibility of rapid and simple quantitative demonstration of V. cholerae.

Asunto(s)

Asunto(s)

RESUMEN

The antibacterial activity of moxalactam was studied in vitro against 229 clinical isolates of gram-positive and gram-negative aerobic microorganisms using the agar dilution technique. Mueller-Hinton agar was used as growth medium. The results were compared to those obtained with cefamandole. All isolates of Staphylococcus aureus and Streptococcus pneumoniae were inhibited by moxalactam at a concentration of 8 microgram/ml or less. The concentrations of cefamandole with which the same effect was obtained were 0.5 microgram/ml and 2 microgram/ml respectively. Moxalactam was highly inhibitory against Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis and Proteus morganii - 90% of the strains were inhibited by 0.125 microgram/ml. Moxalactam was highly superior against Proteus rettgeri and Pseudomonas aeruginosa, which are usually resistant to cefamandole: the MIC100 and MIC90 were 0.25 microgram/ml and 8 microgram/ml respectively. High sensitivity was found in strains of Salmonella species, nine of which were Salmonella typhi: the MIC90 was < 0.063 microgram/ml versus the eightfold higher concentration of cefamandole. The broad-spectrum activity and unusual MIC patterns of moxalactam - eight or manyfold higher concentrations of cefamandole were needed to inhibit 90% of most gram-negative strains studied - make moxalactam an unusual and promising antibiotic.

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)