Harry Raymond Ingham

INHIBITION OF PHAGOCYTOSIS IN VITRO BY OBLIGATE ANAEROBES

A variety of species of obligate anaerobes have been shown to interfere with the phagocytosis and killing of Proteus mirabilis and other aerobic bacteria in vitro. Although all the obligate anaerobes examined showed this activity, the effect was greatest with strains of Bacteroides melaninogenicus and B. fragilis. In contrast, none of the 36 aerobes tested acted in this way. These observations suggest that the presence of obligate anaerobes may be fundamental to the pathogenesis of some types of infections.

PHAGOCYTOSIS AND KILLING OF BACTERIA IN AEROBIC AND ANAEROBIC CONDITIONS

Phagocytosis and intracellular killing of several facultative anaerobes were observed in aerobic and anaerobic conditions. The presence of anaerobes affected these processes. Bacteroides asaccharolyticus and B. fragilis were killed by phagocytes only at bacterial concentrations less than 1 x 10(7) cfu/ml; at higher concentrations of the anaerobes, killing of B. fragilis and concomitant facultative anaerobes was inhibited. This effect appeared to be due to an interaction, in appropriate reducing conditions, between anaerobe and serum, which allowed engulfment of organisms by phagocytes but markedly impaired intracellular killing.

ABSCESSES OF THE FRONTAL LOBE OF THE BRAIN SECONDARY TO COVERT DENTAL SEPSIS

The bacterial species found in pus aspirated from brain abscesses in two patients were typical of those found in dental sepsis. Subsequently apical-root abscesses were demonstrated in the upper jaws of both patients. This evidence strongly suggests that these cerebral abscesses were secondary to dental sepsis which could have spread from the teeth to the frontal lobes by several possible antaomical pathways.

CHARACTERISTICS OF MOTILE CURVED RODS IN VAGINAL SECRETIONS

Motile curved rods seen in vaginal secretions have been isolated on Columbia agar supplemented with 5% human blood and vitamin K. Growth occurred anaerobically and in 5% oxygen but not in more aerobic conditions. There were two distinct groups of these organisms, distinguishable by morphology, biochemical activity and susceptibility to metronidazole. All isolates were sensitive to a wide range of antimicrobial agents, with the exception of nalidixic acid and polymyxin, but one group was resistant to metronidazole. There was little difference between the results of tests of susceptibility to aminoglycosides or to metronidazole performed in anaerobic and microaerophilic conditions. Motile curved rods were isolated from 18 of 80 patients with a clinical diagnosis of non-specific vaginitis, but from only two of 39 without the disease.

Microbiology, chemotherapy and mortality of brain abscess in Newcastle-upon-Tyne between 1979 and 1988

71 patients admitted to Newcastle Regional Neurosurgical Centre between 1979 and 1988 with a diagnosis of brain abscess are reviewed. The overall mortality was 9.9%, with an operative mortality of 7%. The bacteriology of these abscesses is discussed in detail, together with the importance of effective standardized antimicrobial treatment regimens. The low mortality figures appeared to be in direct relationship to early recognition of this condition, prompt surgical intervention and effective chemotherapy.

A study of carbon dioxide-dependent strains of Streptococcus milleri.

Forty-four strains of non-haemolytic streptococci, from a variety of sites, that required CO2 for aerobic growth were identified as Streptococcus milleri. Of these strains, 40 (90%) possessed the Lancefield group-F antigen, the remainder being non-groupable with antisera to the group antigens A, C, F and G.

The use of spore strips for monitoring the sterilization of bottled fluids

A bacterial spore test has been developed which enables the efficacy of the sterilizing cycle recommended by the British Pharmaceutical Codex (1973) for bottled fluids to be accurately monitored. During a 14-month period this test detected faults in 3.3% of the sterilizing cycles, representing five distinct episodes of sterilization failure that passed unnoticed by the conventional controls of physical measurements and sterility testing. There were no failures of sterilization as detected by conventional techniques which were not indicated by the spore test.

A Model for Investigating Polymorph Function in the Presence of Non-Sporing Anaerobes

At a concentration of less than 107 bacteria per ml, non-sporing obligate anaerobes are phagocytosed and killed under aerobic and anaerobic conditions, as are a range of facultative anaerobes. At higher bacterial concentrations the phagocytic killing of non-sporing obligate anaerobes is inhibited as is that of concomitant faculative anaerobes; the latter do not themselves inhibit phagocytic killing. The inhibitory effect occurs only in the presence in the reaction mixture of suitable reducing substances and appears to be due to an interaction between bacterial cells and serum. Heat labile and heat stable serum factors are involved; the interaction results in unrestricted multiplication of associated facultative anaerobes which accumulate within polymorphs and extracellularly.