26. Retrospective analysis of HIV-infected men with anal cancer attending the Toronto General Hospital Immunodeficiency Clinic, Toronto, Ontario, Canada (1985–2013)

Background The incidence of anal cancer (AC) in Canada is 1.5/100 000 but HIV-infected individuals have incidence rates from 49–144/100 000. It is important to examine risk factors for this difference. Methods: A retrospective chart review was performed to look at risk factors in patients with the diagnosis of ‘anal cancer’ attending the Toronto General Hospital Immunodeficiency Clinic (TGH-IC) in Toronto, Ontario, Canada, from 1985 to 2013. There were 5200 clinic attendees. Results: 36 (0.96%) males attending TGH-IC were diagnosed with AC between 1985 and 2013; 17 (47%) were diagnosed since 2008. 7 (19.4%) are deceased; 6 (16.7%) as a result of AC. Mean age at diagnosis was 56 ± 9.8 years compared with mean age at TGH-IC of 48 ± 15.9 years (P = 0.015). 33 (91.7%) were on anti-retroviral therapy (ART) at time of diagnosis. Compared with current ART use, 30 (90.9%) vs 727 (72.6%; P = 0.015) were on nucleoside reverse transcriptase inhibitors (NRTIs); 22 (66.7%) vs 554 (55.3%; P = 0.015) were on protease inhibitors; 8 (24.2%) vs 471 (47.0%; P = 0.015) were on NNRTIs. Median CD4 count at diagnosis was 265 cells mm–3, compared with the TGH-IC of 425 cells mm–3 (P = 0.04). A tobacco history (former or current) was found in 24 (72.7%) with AC vs 2232 (41%) without AC (P = 0.015). 35 (97.2%) underwent treatment: combination chemotherapy and radiation therapy being the most common in 23 (63.9%). Conclusions: In 28 years, there have been a total of 36 males diagnosed with anal cancer at TGH-IC. They were older, had a lower CD4 count and were more likely to be smokers. Combination chemotherapy and radiation therapy remains the mainstay of treatment for AC.

The HIV-positive dentist: balancing the rights of the health care worker and the patient

We describe a hypothetical case of an HIV-positive dentist without cognitive impairment who uses proper infection control procedures. The dentist's physician notifies the medical officer of health without the dentist's consent. Although HIV-positive health care workers, including dentists, have been identified in the past, proven HIV transmission to patients is very rare. Most authorities recommend that an HIV-positive health care worker be monitored by an expert panel, which could then, if necessary, refer to the regulatory body to revoke or restrict the person's license to practice. Mandatory HIV testing is not required for health care workers because they generally do not pose a risk for infecting their patients; they are, however, ethically and legally obligated to report their HIV status to their profession's regulatory body.

Aortitis due to Salmonella: report of 10 cases and comprehensive review of the literature

We describe ten cases of aortitis due to Salmonella that were treated at the University of Toronto-affiliated Hospitals between 1978 and 1997. Predisposing conditions included hypertension, diabetes mellitus, and myelodysplastic syndrome. Main presenting symptoms were fever and abdominal and back pain. The most frequent site involved was the abdominal aorta, followed by the thoracic aorta. All but one patient were treated with intravenous bactericidal antibiotics; seven also underwent surgery, four with axillobifemoral grafts and three with in situ grafts. Four of seven patients died within 1 month of the surgical procedure (three patients with in situ grafts and one patient with axillobifemoral graft). We also reviewed the pathogenesis, clinical and laboratory characteristics, and treatment of 140 cases of aortitis due to Salmonella reported in the literature since 1948. The use of bactericidal antibiotics, together with early surgical intervention and long-term suppressive antibiotic therapy, has led to improved survival.

Iritis associated with intravenous cidofovir

OBJECTIVE

To report two patients with AIDS and cytomegalovirus retinitis who developed iritis after receiving intravenous cidofovir. Both experienced recurrent symptoms upon rechallenge.

CASE SUMMARIES

Two HIV-positive patients with cytomegalovirus retinitis infections previously controlled with intravenous ganciclovir or foscarnet were treated with intravenous cidofovir. Symptoms of iritis developed after the second or third dose of cidofovir. One patient experienced symptoms unilaterally, while the other patient had bilateral symptoms. In both patients, the iritis resolved with topical ophthalmic therapy, but recurred following subsequent infusions of cidofovir. Therapy with cidofovir was discontinued, and no further recurrences of iritis were noted. One patient had post-inflammatory fixed dilated pupils.

CONCLUSIONS

Iritis can uncommonly occur in patients receiving intravenous cidofovir and oral probenecid. With prompt drug discontinuation and administration of topical corticosteroids and/or mydriatic agents, symptoms are usually reversible.

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.

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.

Successful treatment of systemic and local infections due to Exophiala species

We report the successful treatment of three cases of infection due to Exophiala species. These organisms belong to the heterogeneous group of dematiaceous (darkly pigmented) fungi. Two cases of infection occurred in organ transplant recipients who were receiving immunosuppressive medications. Both of these infections remained localized to the subcutaneous tissues and were successfully treated with surgical excision of the lesions. We also describe what is to our knowledge the first reported case of prosthetic valve endocarditis due to Exophiala castellanii that was managed with a combination of medical and surgical therapies. Exophiala species remain an uncommon cause of infection. However, as the population of immunocompromised patients continues to grow and further improvements in the microbiological techniques for identification of these fungi occur, these organisms will be recognized with increasing frequency as a cause of human disease.

Hepatitis C virus infection in patients infected with the human immunodeficiency virus

The prevalence and characteristics of hepatitis C virus (HCV) infection in 226 patients who were seropositive for human immunodeficiency virus (HIV) were determined. Antibody to HCV (anti-HCV) was detected by enzyme immunoassay (EIA), and positive results were confirmed by a neutralization EIA or recombinant immunoblot assay. The prevalence of anti-HCV was 8%. Intravenous drug use was the most common risk factor for HCV infection (61.1% of patients), and 52.4% of intravenous drug users were seropositive for anti-HCV (HCV+). Only 16.7% of HCV+ patients had AIDS, as compared with 37.4% of anti-HCV-seronegative (HCV-) patients (P = .04). The prevalence of hepatitis B virus markers in patients with and without anti-HCV was similar. The CD4+ lymphocyte counts were higher for HCV+ patients than for HCV- patients (P = .001), and the prevalence of anti-HCV decreased in parallel with CD4+ counts. Elevated liver function test values were more common for HCV+ patients than for HCV- patients (61.1% vs. 26.0%; P < .01), but abnormalities were usually slight (< 2-fold elevation in values). HCV viremia was detected by the polymerase chain reaction in 88.2% of HCV+ patients. Despite the coexistence of HIV and HCV infection, liver disease appeared to be mild, and HCV infection did not appear to increase the severity of HIV infection. Serological tests for HCV appear to underestimate the prevalence of HCV infection in patients with advanced HIV infection or AIDS.

Aeromonas hydrophila infections of skin and soft tissue: report of 11 cases and review

We report the clinical and microbiological characteristics of 11 cases of Aeromonas hydrophila infection of skin and soft tissue, and we review the English-language literature on such infections. Of our 11 patients, seven (64%) presented to the hospital between the months of May and September (inclusive). Three patients (27%) had an underlying systemic illness, and two (18%) had nosocomially acquired infection. The nine patients with community-acquired infection had all experienced antecedent trauma, and seven (78%) of these nine reported recent exposure to freshwater. All patients had clinical evidence of soft-tissue inflammation, and nine (82%) had fever. Four wounds were characterized by a foul odor. The infection was polymicrobial in nine cases (82%). Treatment included the administration of antibiotics in nine instances, but empirical antimicrobial therapy provided coverage against Aeromonas in only two cases. Ten patients required surgical management of their wounds. Posttraumatic wound infections with a history of freshwater exposure should alert the clinician to the possible presence of A. hydrophila. Prompt surgical evaluation of wounds in combination with appropriate antibiotic therapy is recommended for the management of these infections.

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.

Pleural fluid infection caused by Listeria monocytogenes: case report and review

Nine cases of pleural fluid infection caused by Listeria monocytogenes (one case described here and eight cases previously reported in the literature) were reviewed. Eight patients (88.9%) had an underlying malignancy (three had Hodgkin's disease, three had non-Hodgkin's lymphoma, and two had leukemia), and six (66.7%) were receiving immunosuppressive therapy at the time of presentation. Seven patients (77.8%) presented with fever and five (55.6%) with respiratory tract symptoms. Those with symptoms of greater than 3 weeks' duration had a relatively poor prognosis. Bacteremia was documented in five patients (55.6%). Examination of pleural fluid typically revealed normal levels of glucose, slightly elevated concentrations of protein, and a negative gram stain. Four patients died, for an overall mortality of 44.4%. Mortality appeared to be lower for patients who received a combination of penicillin or ampicillin plus an aminoglycoside and for those who underwent drainage of pleural fluid than for those not given such treatment. Rapid diagnosis, prompt institution of appropriate antimicrobial therapy, and drainage of the pleural fluid are likely to improve the chances for survival in listerial infection of pleural fluid.

Behçet's disease in a patient with immunodeficiency virus infection

A patient with human immunodeficiency virus (HIV) infection who developed Behçet's disease is described. As various vasculitis syndromes have been encountered recently in association with HIV infection it is suggested that Behçet's disease may be related to the HIV infection in this patient.

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.

Purification and characterization of the Dr hemagglutinins expressed by two uropathogenic Escherichia coli strains

The fibrillar Dr hemagglutinins expressed by two uropathogenic Escherichia coli isolates were mechanically sheared from whole cells and subsequently purified by using anion-exchange high-pressure liquid chromatography. The isolated hemagglutinins were proteins with apparent subunit molecular masses of 14,500 daltons by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and isoelectric points of 5.4 in denaturing isoelectric focusing gels. The two proteins were serologically related to each other but distinct from P fimbriae, as assessed by bacterial agglutination and immunoblotting. The amino acid compositions of the two hemagglutinins were highly similar both to each other and to other Dr hemagglutinins. N-terminal amino acid sequencing of the major hemagglutinin subunit proteins demonstrated homology with afimbrial E. coli adhesins.

The neuropsychological dimensions of postinfectious neuromyasthenia (chronic fatigue syndrome): a preliminary report

Postinfectious neuromyasthenia (PIN) is a clinical syndrome of protracted and incomplete recovery after an apparent viral-like illness. Medical investigation yields few abnormalities which might account for the symptomatology. A substantial number of PIN patients complain of cognitive changes. Specific complaints include impaired attention, concentration and abstraction skills. This study was designed to systematically investigate whether the aforementioned subjective complaints could be quantified objectively using standard neuropsychological instruments. Results indicated that on all tests but one, the subjects' performances were significantly higher than those of their age matched groups in the normative data. Specifically, PIN patients scored significantly better than their age matched norms on tests of concentration, attention and abstraction. What is most striking is the discrepancy between the subjective complaints of cognitive impairment and the objective results of the subjects' performances on all tests. These findings suggest that psychological factors may play an important role in the cognitive functioning of individuals diagnosed with postinfectious neuromyasthenia.

Detection of pilus subunits (pilins) and filaments by using anti-P pilin antisera

P pilus filaments are important in binding to globoside through an adhesin located at the tip of the pilus. There is considerable antigenic variation among P pili, and the immunologic response is usually serotype specific. We purified denatured pilin subunits and used them as immunogens to prepare more broadly cross-reactive antisera. Although antifilament antisera (AFA) detected predominantly the homologous strain, antisubunit antisera (ASA) prepared from two different strains detected P pili in 16 of 16 and 14 of 16 P-piliated strains by Western blotting (immunoblotting). The binding of ASA to the homologous pilus filament was inhibited by only 3 of 17 strains. ASA agglutinated only two of nine heterologous strains and immunoprecipitated pili from one of three heterologous strains. By immunoelectron microscopy ASA was seen to bind to pilus filaments but not as strongly as AFA. Antiserum raised to the denatured pilin subunit was not substantially more reactive with pilus filaments derived from heterologous strains than was AFA. ASA was, however, a very useful probe for detecting most P pilins.

The human antibody response to uropathogenic Escherichia coli: a review

Urinary tract infections caused by Escherichia coli are associated with a local and systemic antibody response. We have studied the serum and urine antibody responses to Escherichia coli in men and women with pyelonephritis, cystitis, and asymptomatic bacteriuria. Protein immunoblots consistently demonstrated serum antibody response to lipopolysaccharide (LPS). Anti-LPS antibody titres rose significantly and progressively when comparing acute with convalescent sera in those who have had their first urinary infection. For those with repeated infections, high titre LPS antibodies were present and did not change significantly between acute and convalescent sera. Antibody responses to the major outer membrane proteins were present but did not differ significantly when compared with normal human serum. A specific anti-P pilus antibody response was demonstrated by immunoblotting. Anti-P pilus antibody was quantitated using ELISA and the titres were found to be very low. Three other techniques were also used to demonstrate the presence of serum antibody. Antibody was detectable by immunofluorescence, but the antigenic specificity of the antibody was more difficult to ascertain. Immunoprecipitation was more specific for determining the nature of the antibody response. Lastly, immunoelectron microscopy was valuable in demonstrating antipilus and antiflagellar antibodies. Immunoelectron microscopy and immunoblotting provided evidence that human antiserum to P pili was modestly cross-reactive and could bind heterologous P pili. These studies indicated that the major antibody response in humans occurs after pyelonephritis and is directed against LPS. An anti-P pilus response is frequently present and is cross-reactive to some extent with other P pili.

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.

Post-infectious fatigue

Post-infectious fatigue or post-infectious neuromyasthenia (PIN) is an illness characterized by persisting fatigue and disability after apparent acute infections. In most cases the illness is attributed to a chronic Epstein-Barr virus infection. Symptoms include weakness and fatigue in the absence of physical findings or significant laboratory abnormalities. These patients are frequently depressed and have considerable disability resulting in prolonged loss of time from work. The illness may be persistent or can be relapsing, but often lingers for two years or more. There is no effective therapy. Pin is probably caused by an acute infection occurring in patients who are psychologically susceptible. They require emotional support, reassurance and explanation.

Depression in patients with neuromyasthenia (benign myalgic encephalomyelitis)

Neuromyasthenia (benign myalgic encephalomyelitis) is a term used to describe a protracted and incomplete recovery phase following viral-like illnesses. There are few significant physical findings or abnormal laboratory determinations. Although depressive symptoms have been observed in individuals with neuromyasthenia, systematic psychological investigations based on a standardized interview technique have not been reported. This study was designed to investigate the prevalence of psychiatric disorders and psychiatric symptoms in a group of patients presenting with neuromyasthenia. The study consisted of three parts: a structured psychiatric interview (The National Institute of Mental Health Diagnostic Interview Schedule), a self-report measure (The Beck Depression Inventory) and Dexamethasone Suppression Test. Results indicated that relative to a matched comparison group of non-clinical volunteers, a significant percentage (67%) of neuromyasthenic patients met criteria for major depression. Even more striking was the observation that 50 percent of the sample had a major depressive episode prior to the development of neuromyasthenia. These findings suggest that sporadic neuromyasthenia may be the result of an organic illness in psychologically susceptible individuals.

Nonopsonic phagocytosis of nonmucoid Pseudomonas aeruginosa by human neutrophils and monocyte-derived macrophages is correlated with bacterial piliation and hydrophobicity

We have shown previously that some strains of Pseudomonas aeruginosa from patients with cystic fibrosis are phagocytized by human polymorphonuclear leukocytes in the absence of serum opsonins. The purpose of this study was to identify the bacterial features which render certain strains susceptible to nonopsonic phagocytosis. Three strains were phagocytized by human neutrophils and monocyte-derived macrophages, and two were not, as determined by luminol-enhanced chemiluminescence, visual inspection of stained smears, and bactericidal assay. Strains that were phagocytized formed pellicles when grown in static broth, but the phagocytosis-resistant strains did not. The phagocytosis-susceptible strains were more heavily piliated and more hydrophobic than the resistant strains. Bacteria exposed to heat (60 degrees C) or UV irradiation were depiliated, as assessed by electron microscopy, and rendered resistant to phagocytosis. When P. aeruginosa was grown on agar, it was piliated, hydrophobic, and susceptible to nonopsonic phagocytosis, but when grown to stationary phase in shaken broth, it was nonpiliated, less hydrophobic, and resistant to phagocytosis. It appears that nonopsonic phagocytosis of certain P. aeruginosa strains by human polymorphonuclear leukocytes and macrophages is facilitated by hydrophobic interactions which may be determined in part by pili.

Experimental meningococcal infection in mice: a model for mucosal invasion

A more complete understanding of meningococcal disease has been hampered by the lack of an appropriate animal model. Previous models have utilized injections of meningococci, which precludes the study of nasopharyngeal colonization and invasion. We have developed a model for meningococcal disease in which litters of 5-day-old mice are challenged intranasally with 10(7) viable meningococci. Bacteremia is monitored by jugular venous blood cultures, and cerebrospinal fluid is sampled by cisternal punctures. Human disease-associated and carrier strains were compared; nasopharyngeal colonization was similar for these bacteria, but the case-associated strains were much more frequently invasive and caused bacteremia. Twenty-one percent of bacteremic animals had meningitis. There was an age-related susceptibility to infection which correlated inversely with the levels of serum complement. Preinjection of iron dextran increased the number of animals which were bacteremic, the concentration of bacteria in blood, and nasopharyngeal colonization. Noncapsular variants of virulent meningococci did not colonize nasopharyngeal tissue in vivo, and they were not invasive. This neonatal mouse model mimics meningococcal disease as seen in humans and may be useful in studying the initial events in the pathogenesis of meningococcal disease.

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.

Immunochemical characterization of P pili from invasive Escherichia coli

P pili (or fimbriae) are present on most pyelonephritogenic Escherichia coli strains, and they mediate binding to erythrocytes and epithelial cells. To determine the antigenic diversity of P pili, we purified the pili from 14 bacteremic E. coli strains which caused mannose-resistant hemagglutination. Pilus preparations consisted of one to three bands in sodium dodecyl sulfate-polyacrylamide gel electrophoresis and ranged in molecular weight from 14,000 to 19,500. There was no single band common to all the strains. An enzyme-linked immunosorbent inhibition assay detected 20 ng of pilus antigen. When four different rabbit antisera were used, only two or fewer heterologous strains could inhibit the enzyme-linked immunosorbent assay. Immunoblots yielded the same results. Protein sequences of four P pili had identical N termini. These results show that despite having identical amino-terminal sequences, P pili are antigenically heterogeneous. The receptor-binding domains which are likely to be identical in all strains must be immunorecessive.

Invasive external otitis: review of 12 cases

Invasive external otitis is an infection caused by Pseudomonas aeruginosa that often occurs in elderly people with diabetes. Twelve cases that illustrate the problems associated with the clinical recognition and successful outcome of the condition were reviewed. The patients' average age was 62.5 years, and they had been ill for an average of 1.8 months before admission to hospital. Predisposing factors included diabetes, swimming in a warm climate and the use of a hearing aid. Radionuclide bone scanning and surgical exploration revealed pathognomonic findings. Initial therapy was often suboptimal: one or more relapses occurred in seven of the patients. All of the patients were cured without relapse after a minimum of 4 weeks of therapy with tobramycin plus an anti-Pseudomonas penicillin. The average duration of the illness was 3.9 months. The outcome in invasive external otitis should be excellent if the condition is diagnosed early and appropriate therapy is instituted.

Blastomycosis during pregnancy

Disseminated blastomycosis with extensive involvement of the lungs, skin and bones was diagnosed in a 31-year-old woman who was 36 weeks pregnant. No antifungal treatment had been given while she was pregnant, and she gave birth shortly after admission to hospital. The child was healthy and uninfected, and there were no signs of inflammation or infection in the placenta. Post partum the mother was treated with 2 g of amphotericin B, with resolution of her symptoms. A literature review suggested that blastomycosis and other systemic fungal infections are more likely to occur during pregnancy because of immunosuppression and that disseminated blastomycosis in pregnant women should be treated with amphotericin B.

Prolonged fever associated with primary hyperparathyroidism

A 36-year-old woman presented with hypercalcemia, hypercalciuria, elevated serum parathyroid hormone levels and prolonged fever. Surgical removal of the hyperplastic and adenomatous parathyroid glands led to reversal of the biochemical abnormalities as well as return of her temperature to normal.

Experimental meningococcal infection in neonatal mice: differences in virulence between strains isolated from human cases and carriers

The lack of availability of a suitable animal model has limited understanding of the pathophysiology of meningococcal disease. We have utilized a neonatal mouse model in which atraumatic intranasal inoculation of meningococci results in nasopharyngeal colonization and ultimately bacteremia. Using this model, we compared the virulence of seven encapsulated meningococcal carrier strains with eight meningococcal strains which were isolated from cerebrospinal fluid or blood of patients (disease strains). Intraperitoneal (IP) iron dextran was given to some animals to enhance meningococcal virulence. After IP iron, carrier strains were still poorly invasive with rates of bacteremia ranging from 0 to 15% (mean = 3%), whereas disease-associated strains were significantly more invasive and caused bacteremia in 31-64% of animals (mean = 39%). Without iron injections, nasopharyngeal colonization rates were similar (36 versus 30%, P greater than 0.1) for case and carrier strains. IP iron dextran significantly enhanced rates of colonization and bacteremia caused by the disease strains only. We have, therefore, shown that the relative virulence of meningococcal strains for humans is maintained in this experimental model.

Experimental meningococcal infection in neonatal animals: models for mucosal invasiveness

A more complete understanding of meningococcal disease has been hampered by lack of an appropriate animal model. We subjected 5-day-old guinea pigs, rats, and mice to intranasal challenge with meningococci and we measured rates of bacteremia as a marker of mucosal invasion. After a single intranasal instillation of 10(7) serotype 2 meningococci, positive blood cultures were found in 0% of guinea pigs, 16% of rats, and 39% of mice, and so mice were used for further studies. Death occurred in 4% of mice and was associated with a purulent leptomeningitis and ventriculitis. Forty percent of mice had nasopharyngeal colonization which increased to 65% with repeated injections. Carrier strains were avirulent, a nonserotype 2 disease strain had low invasiveness, and serotype 2 strains were most virulent. Iron dextran increased rates of bacteremia after challenge with serotype 2 strains. Adult animals were not susceptible to bacteremia after intranasal challenge. The neonatal mouse model fulfills most of the criteria for an appropriate experimental model of meningococcal disease.

Ethionamide-induced goitrous hypothyroidism

A 42-year-old woman developed goitrous hypothyroidism while receiving ethionamide for treatment of an atypical mycobacterial infection. Five weeks after discontinuation of ethionamide therapy, thyroid function had returned to normal. The goitrogenic effect was studied in vitro by incubating ethionamide in various concentrations (10(-3) to 10(-7) mol/L) with ovine thyroid cells in tissue cultures. Ethionamide inhibited the trapping of technetium and organification of iodine at concentrations seen clinically (10(-5) mol/L). Ethionamide appears to be a potential goitrogen in susceptible persons.

Q fever: hazard from sheep used in research

The recent recognition that Q fever is endemic in Ontario and the known occupational risk of Q fever to research personnel working with sheep prompted a study to determine the prevalence of antibodies to the causative organism, Coxiella burnetti, in animals and staff at a Toronto animal research institute. Of 37 sheep 34 (92%) were found to be seropositive--that is, to have a titre of complement-fixing antibody to the phase II antigen of 1:8 or greater. Of 331 staff members tested, 18% were found to be seropositive, compared with 0.6% of a random sample of Toronto blood donors. The highest rate of seropositivity, 68%, was in the 28 animal attendants tested. Seropositivity was associated with working with sheep or fetal lamb tissue (p less than 0.0001) and with visiting the animal facility (p less than 0.001). Of the 59 seropositive staff members 63% had had no direct contact with sheep. There were 12 clinically apparent cases of Q fever, 2 of which required admission to hospital. Q fever remains a serious occupational hazard to staff working in research laboratories using sheep, even to those with indirect exposure to infected animals.

The role of Mycobacterium xenopi in human disease

Mycobacterium xenopi is infrequently recognized as a cause of pulmonary infection. We isolated this organism from 28 patients over a 3-yr period. It was nonpathogenic in 19 and pathogenic in 9. Clinical illness occurred in middle-aged men with other chronic pulmonary diseases. Therapy was associated with clinical improvement, but most isolates were resistant to first-line antituberculosis drugs. The prevalence of M. xenopi varies geographically, but in the province of Ontario, it is second to M. avium-intracellulare as the most common nontuberculous mycobacterial pathogen.

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.

Isolation and characterization of Escherichia coli pili from diverse clinical sources

Bacteria which attach to different mucous membranes should have differing specificities of adherence in vitro. Human Escherichia coli isolates from blood and urine (pathogens) and from stool and throat (commensals) were characterized as to the patterns of hemagglutination (HA), as well as the structure and function of their pili. Bacterial HA was done in microtiter plates and on slides after bacterial growth in broth or agar. Human erythrocytes were agglutinated by 95% of the pathogens and 65 to 70% of the commensals grown in broth or agar. Mannose-resistant HA was characteristically caused by pathogens, and commensals characteristically caused mannose-sensitive HA of guinea pig cells. Strains often had both mannose-resistant and mannose-sensitive reactions, or even a mannose-paradoxical reaction. Pathogens more often caused HA, but titers were lower than those for commensals. Slide HA was less sensitive than the microtiter method. All isolates were piliated. Commensals also had more pili than pathogens when grown in broth (117.8 versus 38.3 pili per bacterium), but pathogens had more pili after growth on agar (32.1 versus 8.1 pili per bacterium). Isolates causing high-titer HA had large numbers of pili (greater than 85 pili per bacterium), but some well-piliated strains were non-hemagglutinating. Pili were purified from seven E. coli strains from different sites of isolation and with different erythrocyte-binding specificity. Pili usually migrated as a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. However, more than one type of pilus could be copurified from some strains since there were two or more bands after separation in octyl-glucoside and two different amino terminal sequences. Protein sequencing was done on five different pili: four resembled type 1 pili and one was a P fimbria. The type 1-like pili (strains 2239 and 9353) had an initial variable sequence of 1 to 5 residues, followed by a common region of 21 residues. The P fimbria (strain 7714) had different erythrocyte-binding specificity but was still 27% homologous with 2239 and 9353. E. coli strains from different body sites have characteristic attachments to erythrocytes. Pili derived from these different sources may also have different binding specificity, but they are similar in primary structure.

Complete heart block in meningococcemia

A 41-year-old man died of meningococcemia after presenting with skin rash, fever, and bradycardia. Electrocardiograms demonstrated intermittent complete heart block, and necropsy showed myocarditis with focal necrosis of the conduction system. This syndrome should be recognized as typical for meningococcemia, and all patients with meningococcal disease should be observed carefully for the development of bradycardia.

Endocarditis caused by M6

M6 is a Moraxella-like organism which is usually of pharyngeal origin and is generally nonpathogenic. Endocarditis caused by M6 occurred in a 31-year-old female with known mitral valve prolapse. The infection quickly responded to ampicillin, but valve replacement was required because of progressive left ventricular failure.

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.

Gonococcal opacity variants: susceptibility to antimicrobial agents

We tested the susceptibility of 34 pairs of isogenic opaque and transparent colony variants of gonococci to nine antimicrobial agents. Only 20% of the opaque and transparent minimal inhibitory concentrations were discordant, and the mean minimal inhibitory concentrations were not significantly different. Selection of opacity variants is, therefore, not necessary for routine susceptibility testing.

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.

Group G streptococcal arthritis

Four cases of infectious arthritis due to beta hemolytic streptococci, Lancefield Group G are described. Three patients presented with acute polyarthritis involving unusual sites while the 4th patient had acute monoarthritis. All 4 cases had underlying diseases which predisposed them to infection: alcoholism (2 cases), malignant disease (1 case) and diabetes mellitus (1 case). Three patients had coexistent Group G streptococcal infection: endocarditis in 2 and skin infection in 1. With adequate parenteral antibiotic therapy and frequent joint aspiration, the prognosis for return of normal joint function following infection with Group G streptococcus appears to be excellent. These cases demonstrate the need for routine serogrouping of streptococcal isolates in patients with septic arthritis. The importance of recognizing this uncommon type of infectious arthritis is emphasized in view of its prognostic and therapeutic implications.