Intra-strain heterogeneity of gonococcal pili is related to opacity colony variance.

We have purified pili from isogenic opacity colony variants that were derived from 14 gonococcal strains. Pili purified from opaque colonies of one strain usually differed from pili purified from transparent colonies of the same strain. In 10 of the 14 strains examined, the apparent subunit molecular weight of pilin isolated from the opaque variants was larger than that seen with pilin obtained from transparent variants. In addition there were demonstrable intra-strain differences in the isoelectric point and buoyant density of pili derived from the opacity variants. Because gonococci express differing opacity phenotypes during the menstrual cycle, it is possible that the pili of these organisms may also alter in vivo.

Hemagglutination by purified type I Escherichia coli pili.

Many enterobacteria can cause agglutination of erythrocytes, but previous investigations have not proven which components of the bacteria are responsible. We used a strain of Escherichia coli K12 which causes mannose-sensitive hemagglutination (HA) of guinea pig cells. Common pili were purified from these bacteria by shearing them from the bacteria followed by selective precipitation in acid and ammonium sulfate. Isopycnic centrifugation in cesium chloride removed the remaining outer membrane protein contaminants. These pili are pure by electron microscopy and gel electrophoresis. By amino acid analysis, they have a mol wt of 17,099 and consist of 45% nonpolar residues. These purified pili agglutinate guinea pig erythrocytes, a reaction that is inhibited by anti-pili antibodies and by saccharides related in structure to D-mannose. Proteolytic treatment of erythrocytes does not diminish HA but rather increases the pili-induced HA of human cells. Neuraminidase enhances HA and mannosidase slightly diminishes it. It is concluded that purified pili alone cause HA of erythrocytes by binding to mannose-like molecules on the erythrocyte surface. Thus HA by bacterial pili serves as a useful model system for the mechanism of bacterial pili attachment ot cell membranes.

Type I Escherichia coli pili: characterization of binding to monkey kidney cells.

We have demonstrated binding of purified pili from a strain of Escherichia coli to Vero cell monolayers as a model of prokaryotic-eukaryotic cell adherence. Pili bound to the tissue culture in a rapid reaction that did not require enzymatic activation. Attachment occurred optimally at pH 4-5 and could be inhibited by analogues of D-mannose, anti-pili antibodies, or by preincubation of tissue cells with mannose-specific plant lectins. Binding remained after treatment of the monolayer with glycosidases, trypsin, or a protease mixture but was enhanced after neuraminidase treatment. These results indicate that bacterial binding can occur via pili which act like lectins and presumably bind to mannose-containing glycoproteins on mammalian cell surfaces.

Meningococcemia caused by serogroup W135. Association with hypogammaglobulinemia.

Meningococcemia caused by serogroup W135 occurred in four patients during a period of nine months. Three of the patients had hypogammaglobulinemia with normal hemolytic complement levels; the fourth had normal immunoglobulin levels one year after her illness. None of the patients had classic meningitis. One patient had pneumonia; one appeared to have encephalitis with mild meningismus; and two had sepsis without localizing signs or symptoms. Patients with hypogammaglobulinemia are predisposed to the development of meningococcemia, and the incidence of W135 carriage in the population is increasing.

Effects of vitamin E and C supplementation on oxidative stress and viral load in HIV-infected subjects.

OBJECTIVES: The HIV-infected population is known to be oxidatively stressed and deficient in antioxidant micronutrients. Since in vitro replication of HIV is increased with oxidative stress, this study assessed the effect of antioxidant vitamin supplementation on lipid peroxidation, a measure of oxidative stress, and viral load in humans. DESIGN: A randomized placebo-controlled, double-blind study. METHODS: Forty-nine HIV-positive patients were randomized to receive supplements of both DL-alpha-tocopherol acetate (800 IU daily) and vitamin C (1000 mg daily), or matched placebo, for 3 months. Plasma antioxidant micronutrient status, breath pentane output, plasma lipid peroxides, malondialdehyde and viral load were measured at baseline and at 3 months. New or recurrent infections for the 6-month period after study entry were also recorded. RESULTS: The vitamin group (n = 26) had an increase in plasma concentrations of alpha-tocopherol (P < 0.0005) and vitamin C (P < 0.005) and a reduction in lipid peroxidation measured by breath pentane (P < 0.025), plasma lipid peroxides (P < 0.01) and malondialdehyde (P < 0.0005) when compared with controls (n = 23). There was also a trend towards a reduction in viral load (mean +/- SD changes over 3 months, -0.45 +/- 0.39 versus +0.50 +/- 0.40 log10 copies/ml; P = 0.1; 95% confidence interval, -0.21 to -2.14). The number of infections reported was nine in the vitamin group and seven in the placebo group. CONCLUSION: Supplements of vitamin E and C reduce oxidative stress in HIV and produce a trend towards a reduction in viral load. This is worthy of larger clinical trials, especially in HIV-infected persons who cannot afford new combination therapies.

HIV infection in patients over 55 years of age.

We describe the clinical and epidemiological characteristics of human immunodeficiency virus (HIV) infection in patients greater than 55 years of age at the time of diagnosis and make comparisons with younger HIV-infected patients. Patients were selected by stratification according to age (greater than 55 years and less than 40 years) from a large cohort, and information was obtained by review of charts. Three samples of younger patients were used for general comparison (sample 1), for analysis of progression to acquired immunodeficiency syndrome (AIDS) (sample 2), and for analysis of survival after AIDS (sample 3). We identified 33 patients greater than 55 years of age (30 men and 3 women). The mean age was 60.1 years (range, 55-72). Risk factors included homosexual/bisexual, 22 (67%); blood products, seven (21%); heterosexual, two (6%); and unknown risk, two (6%). HIV encephalopathy tended to be more common in the older group, while Kaposi's sarcoma was more common in younger controls. Older patients more frequently acquired HIV infection via transfusion of blood or blood products (p less than 0.005), were more likely to have AIDS at presentation (p less than 0.001), progressed to AIDS more rapidly (p less than 0.002), and had higher mortality rates (p less than 0.001). Transfusion of blood or blood products is an important mode of acquisition of HIV in patients greater than 55 years of age. HIV infection has a more rapid and aggressive course in older patients.

The possible role of corticosteroid therapy for pneumocystis pneumonia in the acquired immune deficiency syndrome (AIDS).

Twenty-one episodes of Pneumocystis carinii pneumonia (PCP) and the acquired immune deficiency syndrome (AIDS) were treated with corticosteroids in the form of intravenous methylprednisolone or oral prednisone. A standard dose of 80 mg/day x 5 days was given for 15 episodes, whereas 6 patients received variable doses of 20-120 mg/day x 4-20 days. All were treated with trimethoprim-sulfamethoxazole (TMP-SMX). Comparison was made with 12 AIDS patients with PCP who were not treated with steroids. The steroid group was more severely ill than the controls as measured by alveolar-arterial oxygen difference but were otherwise comparable. Mortality from the pneumonia in the steroid group was 2/21 (10%) vs. 3/12 (25%) in the control group. Significant differences were seen in the following parameters: time to defervescence (1 day vs. greater than 9.3 days), the proportion of patients with pO2 greater than 70 mm Hg at day 5 [12/21 (57%) vs. 1/12 (9%)] and at day 10 [19/21 (90%) vs. 7/12 (58%)], and number of adverse drug reactions [4/21 (19%) vs. 9/12 (75%)]. There were fewer late relapses [1/19 (5%) vs. 2/9 (22%)] after a 5.5 month (mean) follow-up. All patients had improvements in their clinical status when initially given corticosteroid therapy but early relapses occurred when steroids were discontinued in five patients (24%). No other complications could be attributed to steroid therapy in this study. A brief course of high-dose corticosteroids appears to be beneficial in severely ill AIDS patients with pneumocystis pneumonia. This suggests the need for randomized, double-blind, placebo-controlled trials to confirm these findings.

Gallium-67 scanning in the diagnosis of postoperative sternal osteomyelitis: concise communication.

Sternal osteomyelitis is an uncommon but serious complication of the median sternotomy incision. Definite diagnosis is clinically difficult and radionuclide scanning is of uncertain value in the early postoperative period. We conducted a prospective blind study of gallium scanning in the early period after cardiac surgery and reviewed clinically diagnosed cases that also had scans. Clinical status and scan interpretation were each independently assessed by three raters. Thirty-eight scans included six true positives, five true negatives (no sternotomy) and 27 post-sternotomy, clinically uninfected patients. Using categories of high, medium, and low for scan interpretation, the radiologic assessors agreed 90% of the time. Normal postoperative Ga-67 uptake could usually be differentiated from uptake by an infected sternum. The test had a sensitivity of 83% and specificity 96%. If the clinical (pretest) likelihood of sternal osteomyelitis is 30%, then the gallium scan will have a 90% positive predictive value and a 93% negative predictive value. This study of observer variation and validity indicates that Ga-67 scanning may be useful in confirming the diagnosis of poststernotomy sternal osteomyelitis.

Diagnostic approaches to head and neck infections.

This article covers both the microbiologic techniques for diagnosis of head and neck infections and imaging techniques for localization of those infections. These approaches are used in a detailed discussion of specific infections of the head and neck regions.

Precipitating factors for the chronic fatigue syndrome.

The etiology of the Chronic Fatigue Syndrome (CFS) is unknown but it is usually considered to be postinfectious or postviral. Many infecting agents have been suspected as causative but none has been proven. We investigated precipitating factors in 134 CFS patients through the use of a questionnaire, interview, clinical examination and serology for infecting agents; 35 healthy controls completed a similar questionnaire. CFS started with an apparently infectious illness in 96 (72%) but a definite infection was only found in seven of these 96 (7%). Thirty-eight (28%) had no apparent infectious onset: 15/38 (40%) had noninfectious precipitants (trauma, allergy, surgery). There was no apparent precipitating event in 23/38 (61%). Immunization was not a significant precipitant. Stressful events were very common in the year preceding the onset of CFS (114/134, 85%) but these occurred in only 2/35 (6%) of the controls (p < .0001). The onset of CFS may be associated with preceding stressful events and multiple other precipitants. An infectious illness is not uniformly present at the onset and no single infectious agent has been found; CFS is most likely multifactorial in origin.

Rheumatologic manifestations of infection with the human immunodeficiency virus (HIV).

The aim of this study was to assess the type and frequency of rheumatologic manifestations among patients followed at an HIV clinic in a general hospital, and to evaluate the usefulness of a questionnaire in identifying the presence of these manifestations. Fifty-two consecutive patients with HIV infection completed a questionnaire regarding the presence of rheumatologic symptoms. All patients were interviewed and examined for the prevalence and spectrum of musculoskeletal manifestations. The questionnaire was found to be sensitive in identifying patients with rheumatologic manifestations which were detected on clinical examination. The latter were found in 34 patients (65.3%). Twenty-one patients (40.3%) had arthralgias, 8 (15.2%) had spondyloarthropathies (including Reiter's syndrome, psoriatic arthritis and undifferentiated spondyloarthropathy). Two patients (3.8%) had oligoarthritis and one case each had myositis, Sjögren's syndrome and Behçet's syndrome. Muscle pain was common, occurring in 35% of the patients, and it was related to the use of zidovudine therapy. In contrast to previous reports, most of the patients with arthritis had mild disease, responding promptly to non-steroidal anti-inflammatory drugs. This difference may be explained by the use of zidovudine therapy, stage of HIV infection, and lifestyle. A questionnaire may be helpful in identifying the prevalence of rheumatologic manifestations in HIV-infected subjects.

Bacterial flora of the external canal in diabetics and non-diabetics.

Diabetics are prone to severe Pseudomonas otitis externa, but it is unknown if this is due to abnormal colonization of the external auditory canal. The bacterial and fungal flora of 26 diabetics and 29 age-matched controls was studied and found to be similar. Subjects with diabetes had more cerumen and a past history of more frequent external otitis than non-diabetics. It is concluded that diabetics probably have more frequent and severe external otitis because of undefined abnormal host defense mechanisms and not because of enhanced colonization by pathogens.

Assessment of regional cerebral perfusion by 99Tcm-HMPAO SPECT in chronic fatigue syndrome.

Chronic fatigue syndrome (CFS) is a severely disabling illness of uncertain aetiology. It is characterized by a chronic, sustained or fluctuating sense of debilitating fatigue without any other known underlying medical conditions. It is also associated with both somatic and neuropsychological symptoms. Both physical and laboratory findings are usually unremarkable. Regional cerebral blood flow (rCBF) was assessed in 60 clinically defined CFS patients and 14 normal control (NC) subjects using 99Tcm-hexamethylpropyleneamine oxime (99Tcm-HMPAO) single photon emission computed tomography (SPECT). Compared with the NC group, the CFS group showed significantly lower cortical/cerebellar rCBF ratios, throughout multiple brain regions (P < 0.05). Forty-eight CFS subjects (80%) showed at least one or more rCBF ratios significantly less than normal values. The major cerebral regions involved were frontal (38 cases, 63%), temporal (21 cases, 35%), parietal (32 cases, 53%) and occipital lobes (23 cases, 38%). The rCBF ratios of basal ganglia (24 cases, 40%) were also reduced. 99Tcm-HMPAO brain SPECT provided objective evidence for functional impairment of the brain in the majority of the CFS subjects. The findings may not be diagnostic of CFS but 99Tcm-HMPAO SPECT may play an important role in clarifying the pathoaetiology of CFS. Further studies are warranted.

Human and canine blastomycosis: A common source infection.

In fall 1993 a man and a dog developed blastomycosis after visiting an island off Bayfield Inlet, Georgian Bay, located near Parry Sound, Ontario. The man recovered but the dog died of blastomycosis. It was hypothesized that the common source of exposure was the island since the permanent residences of the two cases were in different cities. One further case of human infection, based on positive serology, and four additional cases of probable canine blastomycosis were identified. All cases had travelled to Bayfield Inlet during summer and early fall 1993. To the authors' knowledge this is the first Canadian report of a common source of infection of human and canine blastomycosis. This report also provides evidence for a new endemic area of blastomycosis infection.

Hemagglutination by Neisseria meningitidis.

The direct agglutination of erythrocytes by Neisseria meningitidis was studied as a marker for adherence. Hemagglutination (HA) was studied by slide test (5-min incubation) and by dilutions in microtitre plates (20-h incubation). Meningococci that were freshly isolated from subjects agglutinated only human cells by slide test but human, dog, rabbit, guinea pig, and rat cells were agglutinated in the microtitre system. Newly isolated strains were piliated and HA positive but pili were lost after 10 passages on agar, and bacteria became HA negative. HA could be maintained by "affinity culturing," which selected markedly adhesive bacteria: erythrocytes with adherent meningococci were isolated and cultured on agar. This procedure was repeated daily. HA titres were unaffected by mannose but were reduced by sonic disruption, trypsinization, ultraviolet irradiation, heating (65 degrees C), and formaldehyde. Encapsulated (serogroupable) bacteria had low HA titres compared with nongroupable strains, and purified capsular polysaccharides A and C inhibited HA. Meningococcal HA is probably mediated by pili and modified by other factors such as encapsulation. Colonial variation was not a reliable indicator of piliation, and HA is best used for this purpose.

The differential susceptibility of gonococcal opacity variants to sex hormones.

Neisseria gonorrhoeae exist in transparent (Tr) and opaque (Op) colony forms. Op forms are recovered from patients early in the menstrual cycle; Tr colonies predominate late in the cycle. The mechanism for this colonial variation was examined by determining the influence of gonodal hormones on growth inhibition of Op and Tr isogenic variants of gonococci. The estrogens, estrone and estradiol, enhanced growth whereas 19-nortestosterone, testosterone, and progesterone significantly inhibited gonococcal growth. Testosterone and progesterone inhibited growth of the Op variants to a greater degree than the Tr variants. Mixture of Tr and Op colonies grown in the presence of progesterone became predominantly Tr, as occurs in the luteal phase of the menstrual cycle. This study supports the hypothesis of hormonal influence on colonial variation but employed artificial in vitro conditions and high hormone levels.

Sporadic postinfectious neuromyasthenia.

Outbreaks of epidemic neuromyasthenia have occurred throughout the world for many years, but sporadic cases have only recently been recognized. Fifty consecutive previously well patients with prolonged and excessive fatigue after an apparent acute infection were investigated. Most were well educated, active, unmarried women aged 30 to 40 years. The precipitating infection had many clinical presentations. The chronic phase of the illness was characterized by a fairly common set of symptoms. Physical examination and laboratory testing generally gave normal results. Of the 50 patients 16 were found to be infected with Epstein-Barr virus, 7 with other viruses, 4 with parasites and 2 with Mycoplasma pneumoniae. The causative agent was not known in 22 cases. The mean duration of the illness was 27.6 months, and the mean proportion of time lost from work or school was 39%. Drug therapy was not beneficial; supportive therapy was useful. Further investigation is required to determine optimal management of sporadic neuromyasthenia.

Effect of subinhibitory concentrations of antimicrobials on meningococcal adherence.

Meningococci adhere to human pharyngeal cells and agglutinate erythrocytes. These events are dependent upon pili and are reduced by encapsulation. The effect of subinhibitory concentrations of seven antimicrobials on meningococcal adherence, antimicrobials on meningococcal adherence, piliation, hemagglutination (HA), and bacterial proteins was studied to determine their potential for modifying virulence. Piliation was reduced by most antibiotics but was most markedly (greater than 70%) reduced by rifampin, tobramycin, and VCN (vancomycin, colistin, and nystatin). Bacterial proteins as determined by sodium dodecyl sulphate--polyacrylamide gel electrophoresis were altered: tetracycline, sulfamethoxazole, rifampin, and VCN caused loss of a 43-45 K protein and a general decrease in all stainable protein bands, while erythromycin, ampicillin, and tobramycin only caused an increase in a 28 K protein. HA was reduced by ampicillin, tobramycin, erythromycin, and VCN but interstrain variability was present. Epithelial cell adherence was diminished by an average of 45% compared to controls. The meningococcal strains lost HA, piliation, and adherence in the same rank order, however, there was no significant rank correlation of antibiotic inhibitory activities on these parameters. These results indicate that subinhibitory antibiotic concentrations reduce meningococcal piliation and alter other bacterial proteins; these changes are associated with diminished adherence and hemagglutination, alterations which may be markers of meningococcal virulence.