- Volume 17, Issue 2, 1984

The effect of various energy sources and metabolic intermediates on the attachment of Treponema pallidum to baby rabbit genital organ (BRGO) cells in culture was examined. Pyruvate and glucose enhanced the motility of T. pallidum in vitro. Pyruvate increased significantly the attachment of treponemes to BRGO cells when compared with the other substrates but all substrates tested stimulated DNA synthesis by cultured BRGO cells. Thus, the effect of pyruvate on attachment may be due to an effect on the treponemes. Prior exposure of the BRGO cells to the glucose analogue 2-deoxyglucose greatly inhibited the attachment of T. pallidum whereas three other analogues had no effect. The inhibitory effect of 2-deoxyglucose was partially reversed by the presence of pyruvate in the attachment assay. These results suggest that energy metabolism of both T. pallidum and host cells may be required for the initial interaction of T. pallidum with its host in vivo.

A small, fastidious gram-negative anaerobe was isolated from men with non-gonococcal urethritis (NGU). The isolates are described as NGU-associated anaerobes because they were extremely rare in men with urethritis other than NGU, and in asymptomatic men. They showed twitching motility, had many polar pili and appeared to be a homogenous group culturally, morphologically and biochemically. None of the strains fermented or utilised carbohydrates or organic acids as sole sources of carbon for energy and growth. However, growth of all strains was stimulated by formate and fumarate in liquid and solid media, especially in the former where growth seemed dependent on these growth factors. Unlike most anaerobes they produced cytochrome enzyme(s) that might be involved in oxidation-reduction reactions in the presence of oxygen as some of the strains were capable of growing in 5% oxygen. However, growth and energy generally resulted from anaerobic phosphorylation. Strains of this anaerobe seemed to require a low redox-potential (Eh) for survival during transportation but this was not essential for growth. Comparative studies with the other asaccharolytic anaerobes showed some similarity between the NGU-associated anaerobe, Bacteroides ureolyticus and Wolinella succinogenes. Like these, some NGU-associated strains pitted agar media and all produced urease. However, unlike these anaerobes, strains of the NGU-associated anaerobe produced enzymes for the hydrolysis of arginine, and the decarboxylation of lysine and ornithine. They also produced oxidase and some strains haemolysed sheep red cells. However, lactic acid was not an end-product of the metabolism of glucose by any of the strains. The NGU-associated anaerobes are strikingly different from anaerobic vibrios, B. praeacutus and B. asaccharolyticus.

The importance of K antigens from six strains of Escherichia coli for the interaction with polymorphonuclear leukocytes (PMNL) was studied. The major factor influencing this interaction was the ability of strains to activate complement by the classical route during opsonisation, this process being reduced for most K-positive strains. Interference of K antigens with the functioning of common pili as adhesins of eukaryotic cells was not observed nor a toxic effect of K antigens on PMNL.

The influence was studied of lanthanum chloride, chlorpromazine hydrochloride, indomethacin and sodium cromoglycate on the morphological changes induced in Vero cells by the action of the cholera toxin, the thermolabile enterotoxin (LT) and the Vero cell cytotoxin (VT) of Escherichia coli, the enterotoxin of Clostridium perfringens, and the cytotoxin of Clostridium difficile. These drugs were able to inhibit the effects produced by C. difficile cytotoxin but not by the other toxins examined.

The morphological responses of Pseudomonas aeruginosa to N-formimidoyl thienamycin, azthreonam, ceftazidime and cefoperazone were studied by transmission electron microscopy. They were correlated with the results of viable counts and continuous turbidimetric monitoring. N-formimidoyl thienamycin initially caused the formation of abnormally shaped cells which developed into spheroplasts. The other antibiotics caused filamentation of the bacteria, which subsequently underwent lysis. The degree and mechanism of lysis varied between the antibiotics. Exposure to azthreonam also resulted in the deposition of electron-dense intracellular material. As judged by conventional minimum-inhibitory-concentration tests, all the agents exhibited similar activity against the strains of P. aeruginosa tested, with ceftazidime displaying the highest activity. However, N-formimidoyl thienamycin caused the most extensive morphological damage and resulted in the most rapid fall in viable count.

Antigens prepared from several strains of each of 10 Clostridium species were used in an indirect enzyme-linked immunosorbent assay with antisera raised against whole cells of a representative strain from each of the 10 species killed by ultra-violet irradiation. With the exception of C. cadaveris, the antisera gave similar results with antigens prepared from all strains of the homologous species. Antigens prepared from 13 other clostridial species were then investigated in an ELISA system with the 10 representative antisera. The results showed many cross-reactions, particularly in the C. perfringens group, the C. difficile/sordelli group and the C. botulinum/novyi/sporogenes group.

A sensitive and rapid method for the detection of rubella specific IgM by fast protein liquid chromatography and enzyme-linked immunosorbent assay is described.

In renal failure, infection is a frequent complication and cause of death, which suggests that uraemia impairs immunity. In a comparison of Candida albicans fungaemia, peritonitis and subcutaneous infection in normal and severely uraemic rats, uraemia did not affect the course of these infections. C. albicans is an important pathogen in immunocompromised hosts and we conclude that uraemia is unlikely to be the primary factor that increases host susceptibility to infection with this fungus.

Sequential serum samples obtained from 50 rheumatic fever subjects and from control individuals matched for time, age and geographical location were tested for antibodies against the M-associated protein antigens, MAP I and MAP II. Antibody titres were determined by the complement fixation test with a partially-purified extract of Streptococcus pyogenes serotype M30 as the MAP I antigen and an acid extract of serotype M48 as the MAP II antigen. Titres of MAP I antibody exceeded those of MAP II antibody in all but six rheumatic fever subjects. Anti-MAP I titres in excess of 40 were significantly more common in rheumatic fever subjects than in matched controls (p < 0.001) or matched subjects with a diagnosis of acute post-streptococcal glomerulonephritis (p < 0.01). Peak MAP I titres were present at the time of admission to hospital in the sera of 40 of the 50 rheumatic fever subjects. In the remainder peak titres occurred within 10 days. Antibody titres were maintained for a mean of 10.3 weeks before declining. Changes in MAP antibody titres were independent of changes in antistreptolysin O and anti-DNAase B titres. Normal children aged between 6 and 15 had higher MAP antibody titres than 2-5-year-old children. Rheumatic fever subjects had significantly higher mean titres of MAP I antibody than matched controls in each age group.

During a period of 12 months, 57 strains of Proteus were isolated from the ears of 38 unrelated patients with chronic suppurative otitis media. Each strain was identified, typed for bacteriocin production and sensitivity, and tested for Dienes compatibility. The majority of the strains (79%) were P. mirabilis; all but one of the remainder were P. vulgaris. Although 19 different bacteriocin production/sensitivity types were found, two rare types, P. mirabilis P7/S5,12 and P. vulgaris P0/S9, were associated with 47% of these infections. This was confirmed by Dienes typing.

Patients with bilateral ear disease carried a different strain in each ear. There was no evidence that persistence of infection had arisen because of the development of antibiotic resistance. Although there was some evidence that persistence may have been the result of reinfection, the isolation of these rare types of Proteus from so many patients with chronic suppurative otitis media may indicate that they play an important role in the pathogenesis of the disease. Most of the Proteus isolates were of “non-faecal” types and it is believed that infection had arisen by a route other than the faecal-aural one.

Agglutinins to certain species of Eubacterium and Pepto-streptococcus have been reported in sera from a high proportion of patients with Crohn’s disease. Because this might be a non-specific finding common to patients with diarrhoea associated with damaged intestinal mucosa, we have compared the incidence of such agglutinins in patients with Crohn’s disease with that seen in patients in North-East India with acute or chronic diarrhoea. The incidence of agglutinins in Crohn’s disease was 44%, compared with 11% in acute and 17% in chronic diarrhoea. These figures suggest that mucosal damage alone does not explain the high incidence of agglutinins in Crohn’s disease.