- Volume 25, Issue 4, 1988

Bacteria isolated from 108 intra-uterine contraceptive devices (IUCD) removed from patients with pelvic inflammatory disease (PID), haemorrhage, pregnancy and from asymptomatic women, and from the genital tracts of 66 healthy controls not wearing an IUCD, were studied. No significant differences were found in the types of micro-organisms or isolation rates from IUCDs removed from women in the various clinical groups. The isolation rate of anaerobic bacteria from IUCDs removed from asymptomatic wearers was significantly lower than that from controls, with the exception of the isolation rate of actinomyces which was significantly higher in IUCD wearers and A. israelii was recovered only from IUCDs. The isolation rates of the different bacterial species varied with the duration of the device in utero. The presence of a copper IUCD altered the bacterial flora of the female genital tract. The insertion of such a device and the ecological changes that follow play a crucial role in the development of PID.

The microbial composition of samples of gastric juice from eight achlorhydric patients was determined by aerobic and rigorously anaerobic culture techniques. Bacteria from 16 genera were commonly isolated, but representatives of only three genera, (streptococci, neisseriae and haemophili) were isolated from every patient. Nitrate and nitrite were both reduced by veillonellae, haemophili, staphylococci, corynebacteria, lactobacilli, flavobacteria and fusobacteria, but the potential rate of nitrate reduction by suspensions of veillonellae, Haemophilus parainfluenzae and members of the Enterobacteriaceae were up to ten times more rapid than the rate of nitrite reduction. Conversely, although all Neisseria spp. reduced nitrite only some strains reduced nitrate. Streptococci did not reduce nitrate. Streptococcus sanguis reduced nitrite when grown with haematin ; other streptococci did not reduce nitrite. Bacterial nitrate and nitrite reduction were active over the pH range 6–8, similar to the pH range of the achlorhydric stomach.

From a knowledge of the composition of the bacterial flora and their potential rates of nitrate and nitrite reduction under prevailing conditions, predictions were made about the tendency of nitrite to accumulate during nitrate reduction. Studies of the transient accumulation of nitrite by mixed cultures of H. parainfluenzae and N. subflava were consistent with these predictions. Haemophili and veillonellae could be responsible for the accumulation of nitrite in the gastric juice of some patients, whereas streptococci and neisseriae would tend to remove nitrite from the stomach as rapidly as it formed.

Summary. A series of 133 isolates of methicillin-resistant Staphylococcus aureus was fingerprinted by the immunoblot technique. Extracts were prepared by lysostaphin degradation of overnight cultures and peptides were separated by SDS polyacrylamide gel electrophoresis. The peptides were transblotted on to nitrocellulose membranes and probed with (1) a hyperimmune rabbit serum raised against a methicillin-resistant S. aureus isolate, (2) a hyperimmune rabbit serum raised against an isolate of S. epidermidis, and (3) serum from a patient who had recovered from an infection with a methicillin-resistant S. aureus. This typing method confirmed the existence of an epidemic strain that accounted for 102 of the isolates. The remaining 31 isolates were grouped into a further seven types which correlated with the results of phage typing and antibiograms.

Serum samples from patients infected with Leptospira interrogans serovar hardjo were tested by the microscopic agglutination test (MAT), enzyme immunoassay (EIA) and immunoblotting. There was no apparent correlation between MAT titre and EIA optical density (OD) for individual serum samples, but sequential serum samples produced similar profiles in both tests during the course of an infection. Immunoblotting of hardjo sonicate with patients’ sera revealed reactions with a number of bands, in the mol. wt (103) range 14·4–95. However, all serum samples reacted with the major 28 × 103-mol. wt sub-unit of hardjo lipopolysaccharide (LPS) and most reacted with a (34·5–35) × 103-mol. wt flagella doublet. Examination of sequential serum samples obtained over a period of about 3 months after infection revealed little change in the antigens detected after the second to third week of infection. Absorption of patients’ sera with whole viable leptospires revealed that antibodies to several exposed antigens, including LPS, were produced. Sera which reacted with hardjo flagella also reacted with bands of similar mol. wts in preparations from other serovars.

Serum samples from 101 individuals were titrated for Corynebacterium diphtheriae antitoxin by an IgG-specific enzyme-linked immunosorbent assay (ELISA) and a neutralisation test in tissue culture (TC). In some of the sera, the concentrations of antitoxin determined by the two assays were different; antitoxin values in these sera were titrated again by neutralisation tests in guinea pigs (GNT). Antitoxin concentrations of >0·01 IU/ml by GNT partly corresponded to values obtained in both ELISA and TC. Only the values from TC agreed with lower GNT results. Heat inactivation of sera was investigated and rejected as a possible reason for the discrepancy in the results. ELISA can be used to detect levels of < 0·1 IU/ml, although the accuracy below 0·01 IU/ml, often considered a protective level, is questionable. At higher levels ELISA was reproducible for the titration of diphtheria antitoxin in human sera and offers a useful alternative to both in-vivo assays and TC.

Fimbriae-like filaments were demonstrated on the surface of Bordetella pertussis, serotype 1.3, by negative staining and electronmicroscopy. Immuno-electronmicroscopy with a monoclonal antibody specific for strains possessing agglutinogen 3, and colloidal gold, gave strong labelling of these structures. However, incubation with adsorbed polyclonal anti-agglutinogen 3 serum gave only weak labelling of the distal parts of the filaments and of the bacterial surface. The different binding patterns of the two antisera suggested that the epitopes involved were dissimilar. Thus, agglutinogen 3, as defined by conventional adsorbed sera, appeared to be associated with the fimbriae-like structures but was not necessarily identical to the fimbrial subunit protein. The monoclonal antibody, however, was more likely directed against the subunits of the fimbriae-like structures on serotype 1.3 bacteria.

Two systems for detecting pre-formed enzymes, RapID ANA and a prototype system from API, were compared in a blind study for their ability to identify 69 gram-positive anaerobic cocci isolated from clinical specimens. Both systems were able to identify Peptostreptococcus anaerobius, Ps. asaccharolyticus and Ps. micros accurately without the need for further tests. The prototype API system identified all isolates of Ps. magnus correctly, but the RapID ANA system misidentified several isolates as Ps. micros. Numerous different enzyme patterns were found with the indole-negative, butyrate-producing cocci (Ps. prevotii and Ps. tetradius), suggesting that this group of organisms may be heterogeneous. We conclude that kits for detecting preformed enzymes are of considerable potential for the identification of gram-positive anaerobic cocci in clinical laboratories.