Comparison of latex and haemolysin tests for determination of anti-streptolysin O (ASO) antibodies.

A latex agglutination test was compared with the micro-titration haemolysin inhibition method for the detection of anti-streptolysin O (ASO) antibodies in 428 serum samples. After slight modification of the latex method to produce maximal agglutination good agreement was shown between the results obtained by the two methods. The latex test had a sensitivity of 83.6%, a specificity of 93.3%, a predictive positive value of 86.5% and a predictive negative value of 91.6%. It was convenient, required less labour than the haemolysin test, and permitted economic testing of small numbers of sera.

Comparison of culture media for detecting methicillin resistance in Staphylococcus aureus and coagulase negative staphylococci.

The detection of methicillin resistance was examined in 51 strains of Staphylococcus aureus and 135 strains of coagulase negative staphylococci using Isosensitest, Diagnostic Sensitivity Test (DST), Mueller-Hinton (MH), Columbia, and Sensitest agars. MH agar with 5% added sodium chloride incubated at 35 degrees C was the most effective in detecting resistance in S aureus, and Columbia agar with 5% added sodium chloride incubated at 35 degrees C was most effective for coagulase negative staphylococci. For clinical purposes, a provisional report of sensitivity for S aureus could be issued after 18 hours; with coagulase negative staphylococci, only resistant strains could be reported at this time. For definitive results cultures must be examined after 40 hours of incubation.

Molecular epidemiology of unrelated clusters of multiresistant strains of Haemophilus influenzae.

Three epidemiologically unrelated clusters of Haemophilus influenzae resistant to ampicillin, chloramphenicol, and tetracycline were studied. The biotypes and cell-envelope protein patterns were determined for 17 nonencapsulated strains, 6 from Dundee and 11 from Cheltenham, and for 6 type b encapsulated strains from Guildford. After mobilization by conjugation, large 32- to 36-MDa plasmids were purified from all the strains. The restriction fragment patterns of the plasmids were determined by ethidium bromide staining of digested purified plasmid or by Southern hybridization of digested total cellular DNA of the parent strains, probed with purified plasmid. Evidence is presented for a chromosomal location of the plasmids in the parent strains, the spread in nature of a plasmid between distinguishable strains of H. influenzae, the person-to-person spread of a strain within a cluster, and a high degree of sequence homology between distinguishable plasmids, implying their close relatedness.

Serum interleukin-6 and C reactive protein responses in patients after laparoscopic or conventional cholecystectomy.

OBJECTIVE: To investigate the acute phase inflammatory response to surgical trauma after laparoscopic and conventional cholecystectomy. DESIGN: Prospective open study. SETTING: University Hospital in The Netherlands. SUBJECTS: 21 patients with symptomatic cholelithiasis admitted for elective cholecystectomy who had had no previous upper abdominal operations. INTERVENTIONS: 12 patients underwent conventional, and 9 patients laparoscopic, cholecystectomy. Circulating interleukin-6 (IL-6) and C reactive protein concentrations were measured 6, 12, 24 and 48 hours after operation. MAIN OUTCOME MEASURE: Changes in IL-6 and C reactive protein concentrations, and comparison of operative blood loss and length of stay in hospital. RESULTS: Those treated by laparoscopic cholecystectomy lost significantly less blood (median 60 compared to 100 ml) and spent significantly fewer days in hospital (median 2 compared with 7 days), (p < 0.01 in each case). The only changes in circulating IL-6 concentrations were seen in patients over the age of 60 years who underwent conventional cholecystectomy. There were significant differences in C reactive protein concentrations between the two operations at both 24 and 48 hours after the operation (p < 0.01 in each case). CONCLUSION: We conclude that laparoscopic cholecystectomy reduces the acute phase inflammatory response compared with the conventional operation; there seems to be no relevant correlation between plasma concentrations of IL-6 and C reactive protein; the presence of IL-6 does not affect the response of C reactive protein to trauma; and the response of IL-6 to trauma is age dependent.

Molecular analysis of Tn1546-like elements in vancomycin-resistant enterococci isolated from patients in Europe shows geographic transposon type clustering.

Resistance mechanism relatedness was studied in 18 clinical, European vanA vancomycin-resistant enterococci. Molecular analysis revealed 10 Tn1546-like elements, suggesting two evolutionary lineages. Lineage I dominated the European mainland, and lineage II dominated the United Kingdom and Israel. Geographic clustering reflected different types of meat consumption between countries, since each lineage is associated with colonization of different animals.

Cross-infection by non-encapsulated Haemophilus influenzae.

From October, 1988, to January, 1989, 18 patients admitted to an acute medical chest ward were infected with an ampicillin-resistant beta-lactamase-producing strain of Haemophilus influenzae. All 18 isolates were non-encapsulated strains of biotype III and showed identical cell envelope protein profiles, as judged by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The organism was not isolated from repeated environmental samples but there was strong circumstantial evidence that a spirometer was a common iatrogenic source of the cross-infection.

Persistent Yersinia enterocolitica infection in three rat strains.

Yersinia enterocolitica may persist for prolonged periods of time in humans sometimes resulting in the development of reactive arthritis. To elucidate factors predisposing for persistence we developed animal models. In Lewis and Fischer rats, viable bacteria could be demonstrated for prolonged time and abscesses could be found in the liver, spleen and lungs. Splenic abscesses were observed for more than 20 weeks. Yersinia enterocolitica persisted in Lewis and Fischer rats, but only Lewis rats developed reactive arthritis. In Brown Norway rats abscesses developed early during infection but in contrast to the other strains disappeared after 3 weeks. Culture of homogenized abscess-containing tissue of all three rat strains yielded Yersiniae. Immunofluorescence studies of the abscesses showed diffuse staining inside the abscesses only, indicating the presence of Yersinia enterocolitica antigen. Brown Norway rats, in contrast to Lewis and Fischer rats, developed a different serological reaction pattern against Yersinia enterocolitica antigens and this correlated with the disappearance of the abscesses.

Population-based study of non-typable Haemophilus influenzae invasive disease in children and neonates.

The extent of non-capsulate, non-serotypable Haemophilus influenzae (NST) as a cause of serious invasive disease in children has not been fully defined. We describe the epidemiology of these childhood infections from cases identified during a continuing prospective survey of invasive H influenzae disease in the Oxford region, UK. 408 strains of H influenzae were isolated from cases of invasive disease. 383 (94%) were H influenzae type b (Hib), 24 (6%) were NST strains, and 1 was a type f strain. 3 of the NST strains were non-capsulate type b mutants (b-), but the remaining 21 strains were from the phylogenetically distinct and heterogeneous population of non-capsulate H influenzae (NC). 10 of the NC strains were isolated from neonates with sepsis; crude mortality rate was 40%, with an incidence of 4.6 cases per 100,000 livebirths. 11 NC strains were isolated from children after the neonatal period and under 10 years of age, 4 (36%) of which had severe, unrelated, predisposing conditions. The incidence of NC invasive diseases in these children was 0.5 per 100,000 per year. The attributable mortality for these infections was 10%. Infections due to these H influenzae strains are, after the implementation of Hib vaccines, likely to persist and represent a substantial proportion of the serious infections caused by this species.