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.

Is there a reservoir of sub-clinical lymphogranuloma venereum and non-LGV Chlamydia trachomatis infection in men who have sex with men?

SUMMARY: The aim of this study was to determine if a reservoir of sub-clinical LGV infection exists in men who have sex with men (MSM), as this finding might account for the recent rise in lymphogranuloma venereum (LGV) Chlamydia trachomatis infections among MSM in Canada. MSM without proctitis were enrolled between January and August 2006 in a cross-sectional study. Rectal, urine, serology and pharyngeal specimens were tested for specific C. trachomatis serovars. The median age of the 253 participants was 43 years; 53% were HIV+. We found no active cases of LGV infection; but 20 (8%) participants had positive serology. Thirteen participants (5%) had non-LGV C. trachomatis infections. Unprotected anopenetrative intercourse, rectal enema and drug use were associated with non-LGV C. trachomatis infection. Sub-clinical rectal non-LGV C. trachomatis infection was relatively common but LGV was not identified in our sample. Further studies of screening for non-LGV chlamydia infection in MSM are needed.

A community randomized controlled clinical trial of mixed carotenoids and micronutrient supplementation of patients with acquired immunodeficiency syndrome.

OBJECTIVE: This clinical trial aims to evaluate if natural mixed carotenoids supplementation can improve the health and survival of acquired immunodeficiency syndrome (AIDS) patients. DESIGN: A placebo-controlled, prospective, randomized, double-blind, multicenter clinical trial. SETTING: Community, tertiary care human immunodeficiency virus (HIV) clinics of the Canadian HIV Trials Network (CTN). PARTICIPANTS: Three hundred and thirty-one adults with advanced AIDS on conventional management were recruited during routine clinic visits. INTERVENTIONS: All participants, including 166 controls, received daily oral specially formulated multivitamins including vitamin A and trace elements; 165 treatment group participants received additional daily oral natural mixed carotenoids, equivalent to 120,000 IU (72 mg) of beta-carotene daily. Follow-up was quarterly at routine clinic visits. RESULTS: Mean (s.d.) follow-up was for 13 (6) months. Thirty-six participants died by 18 months. Serum carotene concentration <1.0 micromol/l was present in 16% participants at baseline. Despite variation in carotene content of the treatment medication, serum carotene concentrations increased significantly to twice the baseline levels to 18 months follow-up in participants who received carotenoids treatment compared with controls (P < 0.0001). Although not statistically significant, mortality was increased in participants who did not receive carotenoids treatment compared with those who did (HR time to death 1.76, 95% CI 0.89, 3.47, P = 0.11). In multivariate analysis, survival was significantly and independently improved in those with higher baseline serum carotene concentrations (P = 0.04) or higher baseline CD4 T-lymphocyte counts (P = 0.005). Adjusted mortality was also significantly and independently increased in those who did not receive carotenoids treatment compared with those who did (HR time to death 3.15, 95% CI 1.10, 8.98, P = 0.03). CONCLUSIONS: Low serum carotene concentration is common in AIDS patients and predicts death. Supplementation with micronutrients and natural mixed carotenoids may improve survival by correction of a micronutrient deficiency. Further studies are needed to corroborate findings and elucidate mechanism of action.

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.

Oxidative stress and plasma antioxidant micronutrients in humans with HIV infection.

Increased lipid peroxidation induced by reactive oxygen species may play a role in the stimulation of HIV replication. In this study we compared lipid peroxidation indexes and plasma antioxidant micronutrients between 49 nonsmoking HIV-positive patients with no active opportunistic infection (25 asymptomatic and 24 with AIDS) and 15 age-matched seronegative control subjects. Breath-alkane output, plasma lipid peroxides, antioxidant vitamins, and trace elements were measured. Vitamin C (40.7 +/- 3.02 compared with 75.7 +/- 4.3 mumol/L, P < 0.005), alpha-tocopherol (22.52 +/- 1.18 compared with 26.61 +/- 2.60 mumol/L, P < 0.05), beta-carotene (0.23 +/- 0.04 compared with 0.38 +/- 0.04 mumol/L, P < 0.05), and selenium (0.37 +/- 0.05 compared with 0.85 +/- 0.09 mumol/L, P < 0.005) concentrations were significantly lower in the HIV-positive patients. Lipid peroxides (50.7 +/- 8.2 compared with 4.5 +/- 0.8 mumol/L, P < 0.005), breath pentane (9.05 +/- 1.23 compared with 6.06 +/- 0.56 pmol.kg-1.min-1, P < 0.05), and ethane output (28.1 +/- 3.41 compared with 11.42 +/- 0.55 pmol.kg-1.min-1, P < 0.05) were significantly higher in the HIV-positive patients. These results showed an increase in oxidative stress and a weakened antioxidant defense system in HIV-positive patients. Whether supplementation of antioxidant vitamins will reduce this oxidative stress is still unknown.

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.

Lack of correlation between phenotype activation markers of CD8 lymphocytes and cytotoxic T lymphocyte (CTL) function in HIV-1 infection: evidence for rescue with rIL-2.

CTL activity against HIV-1 antigens expressed on HLA-A-matched EBV-transformed B target cells was detected in 33% (6/18) of freshly isolated PBMC (FPBMC) from patients in the early stages of HIV-1 infection (CDCII). No CTL activity was detected in FPMBC in patients with AIDS (CDCIV). However, the presence of CTL activity did not correlate with the expression of CTL activation markers. A dual-color flow cytometric examination revealed that the CD8+ lymphocytes bearing the memory (CD29) and activation (S6F1) surface molecules increased in number as the HIV-1 infection progressed. This functional and phenotypic discrepancy in memory CD8+ lymphocytes suggests that the memory CD8+ lymphocytes have lost cytotoxic function and become "paralyzed" as the HIV disease progresses. Incubation of PBMC of HIV(+) patients with rIL-2 reactivated predominantly HIV-specific CTL. However, rIL-2 stimulation also activated a "polyclonal or polyreactive" cytotoxic function. The reactivation of CTL function is rIL-2 dosage dependent and the amount of rIL-2 required for reactivation is associated with the severity of the disease. HIV antigen specific CTL in HIV(+) patients can be selectively expanded by HIV antigen stimulation in the presence of rIL-2. These results suggest that the in vivo IL-2 deficiency occurring in HIV-1 infection may be responsible in part for the "paralysis" of HIV specific CTL activity. Such activity can be rescued nonspecifically by exogenous rIL-2 stimulation and expanded specifically by HIV-1 antigen stimulation.

Programmed cell death induced by HIV type 1 antigen stimulation is associated with a decrease in cytotoxic T lymphocyte activity in advanced HIV type 1 infection.

The immune competence of peripheral blood mononuclear cells (PBMCs) from human immunodeficiency virus-seropositive (HIV+) patients was studied by assessing cytotoxic T lymphocyte (CTL) activity following recall HIV antigen stimulation. Target cells were HLA-A-matched EBV-transformed B cells expressing HIV-1 antigen. In the presence of recombinant IL-2 (rIL-2, 2 or 10 U/ml), about 50% of PBMCs from HIV+ asymptomatic patients responded to HIV-1 antigen stimulation in vitro with increased cytotoxic activity. In contrast, PBMCs from patients with overt AIDS, cultured in medium containing rIL-2 (2 U/ml) and HIV-1 antigen, showed no increase in cytotoxic activity; in the presence of rIL-2 (10 U/ml) and HIV-1 antigen, an inhibitory effect on CTL activity was observed. This inhibitory effect was associated with programmed cell death (apoptosis) of CD8+ lymphocytes and cells of both gamma/delta TcR-positive and -negative phenotypes. However, prior to the apoptosis, different TcR phenotypes of T lymphocyte reacted differently to HIV-1 antigen stimulation. The HIV-1 antigen initially appeared to cause gamma/delta TcR-positive T lymphocytes to proliferate and/or differentiate and later induced cell death. Whereas, prior to the apoptosis, no proliferation of gamma/delta TcR-negative T lymphocytes induced by HIV-1 antigen was observed.

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.

Economic analysis of fluconazole versus amphotericin B for the treatment of candidemia in non-neutropenic patients.

Fluconazole (FLU) is an alternative to amphotericin B (AMB) for the treatment of candidemia in non-neutropenic patients. This agent has similar clinical efficacy but significantly reduced adverse effects compared with AMB. Using the database from a Canadian randomised multicentre comparative trial of FLU versus AMB in the treatment of non-neutropenic patients with candidemia, an economic analysis of antifungal therapy was conducted from a Canadian hospital perspective. Patient records were examined for information containing hospital resource consumption. This included the costs for primary intravenous therapy with either AMB or FLU, laboratory tests, patient clinical monitoring and adverse effects management. The robustness of the baseline results were then tested by a comprehensive sensitivity analysis. The mean duration of therapy in the AMB and FLU arms was 17.1 and 23.7 days, respectively (p < 0.001). Assuming that all of the FLU was administered intravenously, the outcomes of the baseline economic analysis revealed that the treatment cost for patients randomized to receive FLU was approximately 50% higher than that for patients treated with AMB [AMB: $Can2370 vs FLU: $Can3578; p = 0.001 ($Can = Canadian dollars)]. In the sensitivity analysis, substitution to oral FLU after 7 days of intravenous therapy produced economic differences that were no longer statistically significant (AMB: $Can2370 vs FLU: $Can2705; p = 0.10). These results suggest that the FLU administration regimen used in the Canadian randomized trial for the treatment of candidemia in non-neutropenic patients may result in increased hospital costs compared with AMB. However, comparable expenditures could be realized if FLU is administered intravenously for the first 7 days and then orally in patients whose condition allows for reliable oral therapy.

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.

Symptomatic and health status outcomes in the Canadian randomized MAC treatment trial (CTN010). Canadian HIV Trials Network Protocol 010 Study Group.

Our objective was to compare the effect of 2 regimens for treatment of Mycobacterium avium complex (MAC) bacteraemia in an HIV-positive population on symptoms and health status outcomes using a substudy of an open-label randomized controlled trial. The study was conducted in 24 hospital-based human immunodeficiency virus (HIV) clinics in 16 Canadian cities. Patients had HIV infection and MAC bacteraemia and were given either rifampin 600 mg, ethambutol 15 mg/kg daily, clofazimine 100 mg daily and ciprofloxacin 750 mg twice daily (4-drug arm) or rifabutin 600 mg daily (amended to 300 mg daily in mid-trial), ethambutol 15 mg/kg daily and clarithromycin 1000 mg twice daily (3-drug arm). The primary health status outcome was the change on the 8-item symptom subscale of the Medical Outcome Study (MOS)-HIV Health Survey adapted for MAC. Changes on other MOS-HIV subscales and on the Karnofsky score were also evaluated. Patients on the 3-drug arm had better outcomes on the MOS-HIV symptom subscale at 16 weeks (P=0.06), with statistically significant differences restricted to night sweats and fever and chills (P < 0.001). The proportion of patients improving on the symptom subscale relative to baseline was 55% on the 3-drug arm and 40% on the 4-drug arm. Patients on the 3-drug arm also had better Karnofsky score at 16 weeks (P < 0.001) and better outcomes on the social function, mental health, energy/fatigue, health distress and cognitive function subscales of the MOS-HIV. The 3-drug arm is superior to the 4-drug arm in terms of impact on MAC-associated symptoms, functional status and other aspects of health status.

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.