Prevalence and macrolide resistance phenotypes and genotypes among clinical isolates of Streptococcus pneumoniae collected in Sofia, Bulgaria from 2001 to 2005.

A total of 328 clinical isolates of Streptococcus pneumoniae were analyzed to determine the rate of macrolide and penicillin resistance as well as macrolide resistance phenotypes and genotypes. Erythromycin resistance was found in 81 pneumococcal isolates (24.7%) and 10.7% of isolates were clindamycin resistant. The prevalence of penicillin G-intermediate (minimum inhibitory concentrations, MICs, 0.125 to 1 microg/ml) and penicillin-resistant (MICs, >or=2 microg/ml) S. pneumoniae isolates was 25.6% and 13.7%, respectively. The rate of ceftriaxone-intermediate and ceftriaxone-resistant strains was 2.7% and 1.2%, respectively. Among erythromycin-resistant S. pneumoniae isolates, strains harboring mef(A) genes (n=42; 51.8%) were found to be predominant over strains with erm(B) genes (n=34; 42.0%). One (1.2%) isolate carried both erm(B) and mef(A), while 4 (4.9%) isolates carried L4 protein mutations. By using the erythromycin, clindamycin and rokitamycin triple-disk test, 42 strains were assigned to the M phenotype of macrolide resistance, 31 isolates were assigned to the partially inducible (iMcLS) phenotype, 4 were assigned to the constitutive (cMLS) phenotype. Four strains with L4 gene showed a rare phenotype with the triple-disk test. Serotyping of S. pneumoniae isolates suggested that serotype (or serogroup) 14, 6 and 19 were predominant (81.5%) among erythromycin-resistant strains. Among mef(A) positive isolates serotype 14 was predominant, among erm(B) positive isolates serogroups 6 and 19 were the most prevalent.

Immunoglobulin enhancer HS1,2 polymorphism: a new powerful anthropogenetic marker.

The human HS1,2 enhancer of the immunoglobulin (Ig) heavy chain 3' enhancer complex plays a central role in the regulation of Ig maturation and production. Four common alleles HS1,2-A*1, *2, *3, *4 are directly implicated with the transcription level and at least one of them, HS1, 2-A*2, seems to be related to immune disorders, such as coeliac disease, herpetiform dermatitis and Berger syndrome. Given their clinical significance it is of interest to know the distribution of HS1,2-A variants in populations from different continents, as well as to determine whether the polymorphism is associated to specific evolutionary factors. In this paper we report the distribution of the HS1,2-A polymorphism in 1098 individuals from various African, Asian and European populations. HS1,2-A*3 and HS1,2-A*4 alleles are at their highest frequencies among Africans, and HS1,2-A*2 is significantly lower in Africans in comparison with both Europeans and, to a lesser extent, Asians. Analysis of molecular variance of the allele frequencies indicates that the HS1,2-A polymorphism can be considered as a reliable anthropogenetic marker.

Flow cytometric determination of neutrophil respiratory burst activity in workers exposed to formaldehyde.

AIM: The aim of the study was to investigate neutrophil respiratory burst activity (NRBA) in workers who were occupationally exposed to formaldehyde. METHODS: NRBA, spontaneous and stimulated with E. coli, N-formyl-methionyl-leucyl-phenylalanine (fMLP) and phorbol 12-myristate 13-acetate (PMA), was studied by means of quantitative flow cytometric determination in 29 workers who were occupationally exposed to formaldehyde; 21 healthy subjects, not exposed to formaldehyde, served as controls. All subjects underwent clinical assessment, including a review of a summary of their medical history and a physical examination. Routine haematological tests were performed. RESULTS: A statistically significant predominance of subjective symptoms and objective clinical findings of chronic upper respiratory tract inflammation, as well as decreased resistance to infections, was observed in the 29 workers exposed to formaldehyde, compared with the controls (chi2 = 9.28, P = 0.02). No statistically significant difference in the spontaneous and stimulated NRBA between the exposed workers and the control group was observed. The spontaneous NRBA (percentage oxidizing cells) was significantly lower in the group of exposed workers with upper respiratory tract findings and frequent and long-lasting infectious inflammatory relapses (median and range 0.45 (0.02-2.03), mean values 0.65 +/- 0.74) than in the healthy controls (median and range 1.35 (0.07-8.69), mean values 2.42 +/- 2.47; P < 0.05), and in the group of exposed workers with rare and short, acute, inflammation of the upper respiratory tract or without any inflammations (median and range 1.00 (0.02-8.67), mean values 1.67 +/- 2.08; P < 0.05). A significant negative correlation between the duration of occupational exposure to formaldehyde and erythrocyte count and haematocrit was found. CONCLUSIONS: The observed decrease of spontaneous NRBA in workers with a history and clinical findings of frequent and long-lasting relapses of chronic inflammation of the upper respiratory tract could be due to formaldehyde exposure and individual susceptibility. The results obtained suggest that functional changes in polymorphonuclear neutrophil granulocytes could serve as an early indicator of an impact of formaldehyde on NRBA. The applied method might be used for identifying groups at increased toxicological risk.