Comparison of antibody repertoires against Staphylococcus aureus in healthy individuals and in acutely infected patients

The management of staphylococcal diseases is increasingly difficult with present medical approaches. Preventive and therapeutic vaccination is considered to be a promising alternative; however, little is known about immune correlates of protection and disease susceptibility. To better understand the immune recognition of Staphylococcus aureus by the human host, we studied the antistaphylococcal humoral responses in healthy people in comparison to those of patients with invasive diseases. In a series of enzyme-linked immunosorbent assay analyses performed using 19 recombinant staphylococcal cell surface and secreted proteins, we measured a wide range of antibody levels, finding a pronounced heterogeneity among individuals in both donor groups. The analysis revealed marked differences in the antibody repertoires of healthy individuals with or without S. aureus carriage, as well as in those of patients in the acute phase of infection. Most importantly, we identified antigenic proteins for which specific antibodies were missing or underrepresented in infected patients. In contrast to the well-described transient nature of disease-induced antistaphylococcal immune response, it was demonstrated that high-titer antistaphylococcal antibodies are stable for years in healthy individuals. In addition, we provide evidence obtained on the basis of opsonophagocytic and neutralizing activity in vitro assays that circulating antistaphylococcal serum antibodies in healthy donors are functional. In light of these data we suggest that proper serological analysis comparing the preexisting antibody repertoires of hospitalized patients with different outcomes for nosocomial staphylococcal infections could be extremely useful for the evaluation of candidate vaccine antigens in addition to protection data generated with animal models.     

Interpretation of gram-stained sputa containing Moraxella (Branhamella) catarrhalis.

Sputum specimens culture positive for Moraxella (Branhamella) catarrhalis were Gram stained with three decolorizer solutions (slow, 95% ethyl alcohol; intermediate, 1:1 ratio of 95% ethyl alcohol and acetone; and fast, acetone alone) for 5, 10, 20, and 30 s. Optimal results were obtained with acetone alone after 10 s or with a 1:1 mixture of acetone and ethanol after 20 s. Inadequate decolorization of M. catarrhalis in sputa is likely if the decolorization solution and exposure time are not optimal and may contribute to underreporting of this organism.     

The occurrence of Chlamydia trachomatis in the semen of men participating in an IVF programme

Chlamydia trachomatis is one of the most common causative agentsof sexually transmitted diseases. The authors studied the occurrenceof C.trachomatis in the semen of 184 asymptomatic men participatingin the IVF programme. Twenty-six (14.1%) of the 184 tested werepositive for C.trachomatis, these patients and their wives receivingdoxycycline capsules twice, 100 mg on the first day and 100mg/day for the following 13 days. This treatment was effectivein 88.5% of the cases and in the rest, treatment continued witherithromycin 250 mg four times/day for 2 weeks. The authorscompared the semen parameters (cell count, motility, morphology,bovine mucus penetration and hypo-osmotic swelling test) inthe infected and non-infected groups and observed no significantdifference between these two groups     

Percoll gradient centrifugation can be omitted in sperm preparation for intracytoplasmic sperm injection

Prior to intracytoplasmic sperm injection (ICSI), seminal fluid is currently washed out from the ejaculated semen and further sperm selection is carried out by a discontinuous Percoll gradient. Possible deleterious effects from the sperm-separating substance Percoll on sperm function or embryo cleavage after in-vitro fertilization (IVF) have, to our knowledge, not yet been reported and the use of Percoll has been widely accepted in IVF. In this study, we examined whether the omission of the Percoll step in the sperm preparation has any influence on the outcome of the ICSI procedure. Two methods of sperm preparation for ICSI were compared in a controlled study on sibling oocytes: washing the semen sample once, followed by a Percoll gradient centrifugation versus washing the sperm sample twice without a Percoll gradient centrifugation. The mean fertilization rates were similar for the two sperm preparation methods: 78.2 +/- 21.4 and 75.0 +/- 24.1% respectively of the intact oocytes displaying two pronuclei. Cleavage rates did not differ statistically between the two groups. Whereas in both groups similar percentages of excellent, good and poor quality embryos were obtained, the percentage of fair quality embryos was significantly higher in the group without Percoll (16.3 +/- 20.1 versus 9.1 +/- 15.7%). However, no statistical differences were observed in either the percentage of transferable embryos or in the percentage of embryos actually transferred or frozen in the two groups. In conclusion, spermatozoa from ejaculates that are washed out from the seminal fluid without any further selection can be used for ICSI without any adverse effect on fertilization and embryo cleavage.      

Analysis of the genetic variability of the 1st (CCC/ACC,P52T) and the 10th exons (bp 1012–1704) of the TSH receptor gene in Graves’ disease

We determined the genetic variability of the 1st (CCC/ACC, P52T polymorphic variant) and 10th exons (bp 1012–1704) of the TSH receptor (TSHR) gene in Graves’ disease. A total of 101 Graves’ patients and 163 control subjects were screened. The A253 mutant allele was carried by nine patients with Graves’ disease (8.91%) and 13 control subjects (7.98%) in heterozygous genotype. No significant difference in the frequency of the mutant allele was found between Graves’ patients and control subjects. These results provide evidence that the A253 polymorphism has no genetic relevance in Graves’ disease. Moreover, the DNA nucleotide sequence of 693 bp of the 10th exon (bp 1012–1704) of the TSHR gene was determined in 15 Graves’ patients. Six patients were homozygous for the wild‐type allele and nine were heterozygous for the mutant allele at the 253rd nucleotide of the first exon. No polymorphism was found in the DNA sequences obtained from leukocytes of Graves’ patients, similarly to the sequences obtained from the nine control subjects. None of the nine patients carrying the A253 polymorphism in the 1st exon of the TSHR had polymorphism in the examined part of the 10th exon, including two additional patients whose thyroid tissue was directly analysed. In all likelihood, the polymorphisms of the examined regions of either the 1st or the 10th exon of the THSR gene do not contribute to the genetic susceptibility to Graves’ disease.