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Polymerase chain reaction (PCR) amplification and colorimetric identification of amplicons were performed to detect Bartonella henselae and Afipia felis DNA in specimens from patients who were clinically and histologically suspected of having cat scratch disease. PCR products were revealed using 2% ethidium bromide agarose-gel electrophoresis and identified with specific probes in a commercial colorimetric hybridization assay (DEIA) (GEN-ETI-K; DiaSorin, Italy). Six paraffin-embedded lymph node biopsies from 18 patients as well as 18 samples of peripheral whole blood and 18 sera were investigated. Bartonella henselae DNA was recovered from the whole blood of four patients, and Bartonella henselae and Afipia felis DNA were detected in one patient's lymph node biopsy. This study suggests that PCR-DEIA is sufficiently sensitive to be considered feasible for the molecular diagnosis of cat scratch disease. [ABSTRACT FROM AUTHOR]

Unlabelled: A case of Bartonella henselae bacteraemia is reported in an immunocompetent 8-year-old boy with cat-scratch disease. Serology to B. henselae, diagnosed by polymerase chain reaction, was positive. DNA was extracted from peripheral whole blood and amplified with specific primers targeting the htrA gene of B. henselae. A non-isotopic hybridization assay with a species-specific oligonucleotide probe was used to detect the amplified product.Conclusion: The polymerase chain reaction can be used for the rapid laboratory diagnosis of bacteraemia in cat-scratch disease. [ABSTRACT FROM AUTHOR]

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Platelet-mediated antibacterial activity against gram-negative microorganisms has been investigated. Data show that human washed platelets possess the ability to partially inhibit growth of Salmonella typhi Ty-2 (a smooth strain) but not of two rough strains of Salmonella minnesota (R345-Rb and R595-Re). On the other hand, no antibacterial activity was noted in the presence of the gram-positive Staphylococcus aureus. This activity is dependent on the length of incubation of platelets with bacteria and apparently is not mediated by platelet soluble factors. Finally, lysis of platelets with Triton X-100 following their incubation with bacteria gives rise to the same degree of antibacterial activity observed in the untreated samples. This implies that the described platelet function does not rely on the possible trapping of bacteria in platelet aggregates. [ABSTRACT FROM AUTHOR]

The effects in vitro of 4 purified lipopolysaccharide (LPS) preparations from Rickettsiae on platelets and leucocytes were studied in rabbits and in man. All LPS induced aggregation in rabbit platelet-rich plasma but to differing degrees. This activity was abolished by inactivation of complement. None of the preparations induced aggregation of human platelets. Both rabbit and human leucocytes, when incubated with each of the rickettsial LPS preparations, generated a potent procoagulant activity (tissue factor). These findings add further support to the concept that rickettsial LPS behave as typical LPS from gram-negative bacteria and may be relevant to the understanding of the mechanism(s) responsible for triggering intravascular coagulation in rickettsial diseases. [ABSTRACT FROM AUTHOR]