Analysis of a hepatitis C screening programme for US veterans.

This study analyses a screening programme for hepatitis C virus (HCV) infection among US veterans in a suburban Veterans Affairs Medical Center, in New York. This is the first study examining all 11 potential risk factors listed in the 2001 National U.S. Veterans Health Administration Screening Guidelines. A retrospective study was conducted of 5400 veterans 'at risk' of HCV, identified through a questionnaire in this institution's primary-care outpatient departments between 1 October 2001 and 31 December 2003. Multivariate logistic regression models were built to identify independent predictors of infection. Of 2282 veterans tested for HCV, 4.6% were confirmed by HCV PCR to be HCV infected. In the multivariate model developed, injection drug use, blood transfusion before 1992, service during the Vietnam era, tattoo, and a history of abnormal liver function tests were independent predictors of HCV infection. Our data support considering a more targeted screening approach that includes five of the 11 risk factors.

Severe babesiosis in Long Island: review of 34 cases and their complications.

Thirty-four consecutive patients were hospitalized with diagnosis of severe Babesia infection over the course of 13 years. The average time from onset of symptoms to diagnosis was 15 days. When compared with uninfected febrile control patients, affected patients complained significantly more often of malaise, arthralgias and myalgias, and shortness of breath (P<.05), and they more often had thrombocytopenia and abnormal liver function (P<.05). Forty-one percent of patients with Babesia developed complications such as acute respiratory failure, disseminated intravascular coagulation, congestive heart failure, and renal failure. Analysis of data revealed that complicated babesiosis was more commonly associated with the presence of severe anemia (hemoglobin level <10 g/dL; P=.01) and higher parasitemia levels (>10%; P=.08). Patients were treated with a combination of drugs that included clindamycin, quinine, atovaquone, or azithromycin. Despite treatment, parasitemia persisted for an average of 8.5 days (range, 3--21 days). Exchange transfusion was performed for 7 patients, and it effectively reduced the high levels of parasitemia. Three patients died. Improved outcomes may result with prompt recognition and treatment of babesiosis.

Enterococcus faecalis endocarditis presenting as meningitis.

Although Enterococcus faecalis is a relatively common cause of infective endocarditis, it rarely causes meningitis. A case of Enterococcus faecalis endocarditis presenting as meningitis in a 74-year-old diabetic man on chronic hemodialysis is reported. A review of the literature showed that the association of enterococcal meningitis and endocarditis has rarely been reported. This clinical association may be more common than previously recognized and it is suggested that echocardiography be considered for all patients with enterococcal hematogenous meningitis in order to rule out endocarditis.

Role of prolonged surveillance in the eradication of nosocomial scabies in an extended care Veterans Affairs medical center.

Although general guidelines for control of institutional outbreaks of scabies have been published, little information is available on the long-term efficacy of these measures in extended care facilities. An epidemic of scabies occurred in a comprehensive care Veterans Affairs facility as a result of an unrecognized case of crusted scabies, with a total of 112 persons affected during a 12-month period. The initial outbreak occurred in the acute care units, with highest attack rates among roommates of the index patient (11/14, 78%) and nursing staff (27/55, 49%). Despite sustained infection control measures, secondary outbreaks continued to occur in the extended care units. Factors contributing to the persistence of the epidemic were transfer of patients with unrecognized infestation within the facility, prolonged latency period and atypical manifestations in elderly patients, and failure of scabicide treatment. In addition, a role may be played by carriage of scabies mites by infested staff members before they have symptoms. Control of the epidemic was only achieved with the following: increased awareness and better scabies recognition, restriction of staff rotation in the facility, and improved communication among primary providers and infection control personnel. Prolonged surveillance may be required for eradication of nosocomial scabies in extended care settings.

C3b generation is affected by the structure of the O-antigen polysaccharide in lipopolysaccharide from salmonellae.

Salmonellae differing in the O-antigen side chain of their lipopolysaccharide were previously shown to activate the alternative pathway of complement to different extents. We now examine the generation of the major cleavage fragment of the complement component C3 (C3b) on these bacteria in a system that contains the purified components C3, B, D, and P but lacks the regulatory proteins H and I. The deposition of C3b in this system reproduces the same pattern obtained earlier with the use of whole serum, with the expected differences among the strains bearing different O-antigen. However, two distinct mechanisms for these differences in C3b generation became apparent. The intermediate activating strain showed 3 to 4 times less initial deposition of C3b than the other two strains. In contrast, the least activating strain showed adequate initial deposition but poor amplification, as shown by 2 to 3.4 lower amplification indexes as compared with those on the other two strains. Binding studies with factor B showed that decreased C3 convertase formation was responsible for the low amplification on this strain. Only 25% of the C3b bound to its surface was able to bind factor B with a high affinity, in comparison with 90% on the other two strains. No differences were found for the binding of factor H among the strains. These studies identify the molecular mechanisms by which these bacteria avoid complement activation.

Isoniazid and ethambutol as a cause of optic neuropathy.

A well-recognized complication of ethambutol use is optic neuropathy, but the potential ocular toxicity of isoniazid is often overlooked. A patient developed optic neuropathy while being treated with isoniazid and ethambutol. The optic neuropathy subsided only when both drugs were discontinued, suggesting an additive toxic effect.

Lipopolysaccharide size and distribution determine serum resistance in Salmonella montevideo.

The survival of Salmonella montevideo during serum treatment depends on the presence of an O antigen (O-Ag) associated with the lipopolysaccharide molecule. In this organism, the O antigen is a polysaccharide composed of 0 to more than 55 subunits, each containing 4 mannose residues together with glucose and n-acetylglucosamine. We used a mutant strain of S. montevideo that requires exogenous mannose for the synthesis of O-Ag. Lipopolysaccharide (LPS) was prepared from these cells grown under three different conditions where the availability of exogenous mannose was regulated such that the average number of O-Ag units per LPS molecule, the percentage of LPS molecules bearing long O-Ag side chains, and the percentage of lipid A cores bearing O-Ag were all varied. These changes in LPS profiles were monitored on sodium dodecyl sulfate-polyacrylamide gels, and cells with different LPS profiles were tested for their ability to survive treatment with pooled normal human serum. Survival in serum was associated with LPS that contained an average of 4 to 5 O-Ag units per LPS molecule, and 20 to 23% of the LPS molecules had more than 14 O-Ag units per LPS molecule. Serum survival was less clearly associated with the percentage of lipid A cores covered with O-Ag. We propose, based on these data and on previous work, that the O-Ag polysaccharide provides the cell protection from serum killing by sterically hindering access of the C5b-9 complex to the outer membrane and that a critical density of long O-Ag polysaccharide is necessary to provide protection.

Failure of therapy in pseudomonas endocarditis: selection of resistant mutants.

Despite optimal use of available antibacterial agents, endocarditis due to Pseudomonas aeruginosa is commonly associated with poor response to medical treatment. Two patients are described in whom emergence of resistance to beta-lactam antibiotics was associated with clinical failure. A subpopulation of resistant mutants (10(-7)) was found within the initial, apparently sensitive population of bacteria. These resistant mutants were similar to posttherapy isolates in their increased production of beta-lactamase and in their identical pattern of resistance to beta-lactam antibiotics. Moreover, the only beta-lactamase produced was type Id, and this enhanced production proved to be constitutive. A relatively large inoculum (10(6) colony-forming units/g of tissue) of bacteria was found postoperatively in the heart valves of both patients. The failure to respond is postulated to be due to the selection of these producers of high levels of beta-lactamase in a large bacterial inoculum.

Pneumococcal psoas abscess.

Primary extrapulmonary pneumococcal disease has become a rarity in modern times. We describe a 40-year-old patient who developed an abscess of the psoas muscle as the only evidence of pneumococcal disease. A predisposing local condition was prior trauma of the psoas muscle, documented by the existence of myositis ossificans circumscripta. This case emphasizes the importance of considering unusual sites of involvement of pneumococcal disease.

Dengue with hemorrhagic manifestations: an imported case from the Middle East.

We report a case of imported dengue with hemorrhagic manifestations seen in a patient who had recently returned from South Yemen. Conspicuous laboratory findings were marked thrombocytopenia and increase in the number of "transformed" lymphocytes. Hemagglutination-inhibition and complement-fixation antibody titers suggest a secondary heterotypic type of infection. Further studies should be done to establish the endemic nature of dengue throughout Yemen and adjacent countries on the Arabian peninsula.