Staphylococcus aureus nasal colonization in HIV-seropositive and HIV-seronegative drug users

Nasal colonization plays an important role in the pathogenesis of Staphylococcus aureus infections. To identify characteristics associated with colonization, we studied a cross-section of a well-described cohort of HIV-seropositive and -seronegative active and former drug users considered at risk for staphylococcal infections. Sixty percent of the 217 subjects were Hispanic, 36% were women, 25% actively used injection drugs, 23% actively used inhalational drugs, 23% received antibiotics, and 35% were HIV-seropositive. Forty-one percent of subjects had positive nasal cultures for S. aureus. The antibiotic susceptibility patterns were similar to the local hospital's outpatient isolates and no dominant strain was identified by arbitrarily primed polymerase chain reaction (AB-PCR). Variables significantly and independently associated with colonization included antibiotic use (odds ratio [OR] = 0.37; confidence interval [CI] = 0.18-0.77), active inhalational drug use within the HIV-seropositive population (OR = 2.36; CI = 1.10-5.10) and female gender (OR = 1.97; CI = 1.09-3.57). Characteristics not independently associated included injection drug use, HIV status, and CD4 count. The association with active inhalational drug use, a novel finding, may reflect alterations in the integrity of the nasal mucosa. The lack of association between HIV infection and S. aureus colonization, which is contrary to most previous studies, could be explained by our rigorous control for confounding variables or by a limited statistical power due to the sample sizes.

In vitro antimicrobial properties of azidothymidine (AZT)

In addition to the activity against a number of retroviruses, azidothymidine (AZT) has antibacterial activity against many bacteria. The effect of AZT on 224 bacterial species, including 25 strains of Salmonella spp. isolated from HIV-positive patients, was tested. AZT had no activity against all the strains of tested Gram-positive bacteria and Pseudomonas species (MIC > 128 micrograms/ml), whereas a different activity against Enterobacteriaceae (MIC range, 128 to 0.06 micrograms/ml) was found. In particular 76% of Salmonella spp. isolated from HIV-positive patients showed MICs > 1 microgram/ml, whereas similar MICs value were found in 50% of the Salmonella strains isolated from HIV-negative subjects. In addition, strains of Salmonella isolated from stools were more resistant to AZT when compared to strains isolated from blood even if this difference was not statistically significant. No correlation was found between length of therapy and Salmonella resistance to AZT in HIV-positive patients and a low incidence of Salmonella relapses in subjects treated with AZT was observed. The possibility that AZT may have an ancillary benefit in controlling some bacterial infections in AIDS patients is discussed.

Isolation of Candida species on media with and without added fluconazole reveals high variability in relative growth susceptibility phenotypes

Mouthwashes from human immunodeficiency virus-positive individuals were sampled for yeasts by direct plating on a differential agar medium with and without added fluconazole and via enrichment broths with and without added fluconazole. The colonies of the yeasts isolated were tested for relative growth in the presence of single concentrations of itraconazole and fluconazole. Among 258 culture plates containing yeasts obtained via different isolation routes from 86 yeast-positive samples, 33 (12.7%) of the plates showed unexpectedly high colony-to-colony variation in relative growth. Intercolony variation was seen in 41 (47.7%) of the 86 isolates when relative growth data were analyzed for all colonies of an isolate tested, regardless of the medium used for isolation. The prevalence of relative growth variability with the azoles was highest for Candida glabrata (100% of 13 isolates), followed by Candida krusei (60% of 5 isolates) and Candida albicans (40% of 53 isolates), and the visual patterns of variability seen in scatter plots of the data showed species specificity. Relative growth phenotypes generally tended to be stable for each yeast colony in subcultures, whether or not the medium used for subculture contained antifungal agents. DNA fingerprinting of stable and variable C. albicans isolates showed changes in band patterns detected with the probe Ca3, suggesting that the variability may have resulted from selection of different subtypes of the yeasts during the isolation procedure. These findings suggest that the yeasts isolated from single clinical samples were often not clonal in nature. The relative growth test revealed colony variability more readily than conventional susceptibility testing.

Characterization of mycobacterial species in clinically diagnosed cases of pulmonary tuberculosis and their HIV status

A total of 75 clinically diagnosed and radiologically evident cases suggestive of pulmonary tuberculosis were selected for study. Sputum sample of each patient was screened for AFB by Ziehl Neelsen staining and culture. On examination 20 smears were found positive for AFB and 55 smears were negative by concentration method. A total of 23 samples were found to be culture positive and 52 were culture negative. Of these, 22 stains were identified as Mycobacterium tuberculosis, one was identified as M. Scrofulaceum. Of the 75 patients 3 were seropositive for HIV-I antibodies. Out of these 3, one was found to be smear and culture positive and was identified as M. scrofulaceum. Other two seropositive patients were smear and culture negative for AFB.

Localised oral histoplasmosis lesions associated with HIV infection

Opportunistic fungal infections account for a significant amount of morbidity associated with HIV disease. We report here a case of localised oral histoplasmosis without evidence of disseminated disease in a patient who lacked stigmata of HIV disease at the time of initial presentation. The diagnosis is based on histology with special stains, complement fixing antibodies in serum, and culture of the organism from fresh tissues. Activation of subclinical disease following an infection in Uganda may explain the development of these exophytic oral lesions in this British resident.

Unusual skin ulceration in an HIV-positive patient who had cutaneous syphilis and neurosyphilis

We present a case of a patient coinfected with syphilis and the human immunodeficiency virus (HIV) who had unusual and severe cutaneous ulceration. The profound immune defects associated with HIV may lead to an altered clinical presentation and a more aggressive course in patients infected with Treponema pallidum. Despite non-confirmatory histological findings, we feel our patient's cutaneous ulcers probably represent superficial gummata, which have failed to resolve completely following currently accepted high-dose antisyphilis chemotherapy.

Epidemiology and diagnosis of HIV-associated periodontal diseases

A review of periodontal disease as a manifestation of HIV infection suggests a shift in emphasis over the past 5 years. Initially the focus was on newly described forms of periodontal disease (i.e., HIV-associated gingivitis or linear gingival erythema (LGE); HIV-associated periodontitis or necrotizing ulcerative periodontitis (NUP). While the clinical definition of LGE varies from study to study, an association between LGE and Candida infection has been described. Furthermore, the prevalence of NUP is quite low and this disorder is associated with severe immunosuppression. In contrast, the focus today is on the accelerated rate of chronic adult periodontitis occurring in seropositive patients. While the organisms that characterize adult periodontitis in seronegative individuals are present in subgingival plaque from seropositive individuals, reports suggest that atypical pathogens are also present (i.e., Mycoplasma salivarium, Enterobacter cloacae). Recent studies from our laboratory have identified a novel strain of Clostridium isolated from the subgingival plaque of injecting drug users that has pathologic potential. This organism, however, was found in both seropositive and seronegative individuals in this cohort, suggesting an association with lifestyle rather than serostatus. In addition, data has been published examining the local host response in periodontitis in seropositive individuals. Distinctly elevated levels of IgG in gingival crevicular fluid (GCF) have been observed in seropositive patients. Furthermore, data from our laboratory examining inflammatory mediators in GCF (polymorphonuclear leukocyte lysosomal enzyme beta-glucuronidase and the pro-inflammatory cytokine interleukin-1 beta) suggests an altered response in patients with HIV infection. The alteration manifests as the absence of the expected strong correlation between polymorphonuclear leukocyte activity in the gingival crevice and clinical measures of existing periodontal disease, as well as elevated levels of interleukin-1 beta in sites with deeper probing depths. Therefore, it can be concluded that the progression of periodontal disease in the presence of HIV infection is dependent upon the immunologic competency of the host as well as the local inflammatory response to typical and atypical subgingival microorganisms.

Prevalence of six periodontal pathogens detected by DNA probe method in HIV vs non-HIV periodontitis

OBJECTIVE

The aim of the study was to examine the prevalence of selected periodontal pathogens associated with HIV and non-HIV related periodontal lesions.

METHODS

Subgingival plaque samples were obtained from both HIV-seropositive and HIV-seronegative patients affected with periodontal disease. DNA probes were used to detect Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Bacteroides forsythus, Eikenella corrodens and Campylobacter rectus.

RESULTS

A actinomycetemcomitans, P. intermedia and B. forsythus (P < 0.05) were more prevalent in HIV-seronegative patients with rapidly progressive periodontitis. Only C. rectus was slightly more prevalent in HIV-seropositive subjects with periodontal diseases, but this was not significant.

[The antibiotic resistance of Staphylococcus aureus strains isolated in units with an elevated nosocomial risk and in outpatient facilities in 1995]

Antibiotic susceptibility testing in 231 strains of S. aureus isolated from patients highly exposed to the nosocomial risk and from patients treated in ambulatories for staphylococcal infections revealed significant discrepancies in respect to the incidence of multiple resistant strains and dispersion of resistance phenotypes. MRSA incidence rose to 58-85% in hospital boards, that indicated an "alarm state" which requests the supply of the efficient antibiotic. The 27.18% of MRSA between the strains isolated in ambulatories points to the risk of spreading this strains abroad the community and into the hospital boards and requests the monitoring of the chemotherapy in such of health carry units and of the antibiotic "automedication".

Oral diseases, mycology and periodontal microbiology of HIV-1-infected women

HIV-1 infection is increasing more rapidly among heterosexual women. Relatively limited information is available on HIV-related oral pathoses in these individuals. To gain insight into the type and occurrence of oral lesions in this population, 25 HIV-1 infected women including asymptomatic, symptomatic and AIDS patients were examined clinically and sampled for detection of oral yeast and characterization of their subgingival microbial flora. Sixty percent of the subjects were African-American, with 80% infected via heterosexual contact. Oral candidiasis was the most common nonperiodontal oral lesion, observed in 44% of the patients. Oral yeast was cultured from all women with candidiasis and 76% of the total subjects. Oral hairy leukoplakia was clinically diagnosed in 16% of the subjects. Clinically mild to moderate gingivitis and periodontitis were observed in 84% and 52% of the patients, respectively. Candidiasis and the presence of cultivable yeast were observed in patients with low, intermediate, and high CD4+ T lymphocyte numbers. Plaque samples were collected from each subject and enumerated by predominant cultivable methods, selective media and microscopy. No differences were detected in the microflora associated with seropositive women with existing periodontitis relative to those without periodontitis or to seronegative women with periodontitis. Candidiasis was the most notable oral clinical manifestation in the HIV-1-infected women and may be a useful clinical indicator of early immune dysfunction mediated by HIV-1.

A morphological study of penile chancroid lesions in human immunodeficiency virus (HIV)-positive and -negative African men with a hypothesis concerning the role of chancroid in HIV transmission

Chancroid, the most common cause of genital ulceration in Africa, is known to be associated epidemiologically with heterosexual transmission of human immunodeficiency virus (HIV). The pathophysiological mechanisms by which chancroid might facilitate the spread of HIV are obscure. To investigate the role of chancroid in HIV transmission, the authors studied the histological features of biopsies from 11 men with penile chancroid lesions including five who were serologically positive for HIV. The histomorphologic and immunophenotypic nature of the inflammatory infiltrates suggests that there is a significant role for cell-mediated immunity in the host response to Hemophilus ducreyi infection. This response may be critical to the role of chancroid in HIV transmission.

Molecular epidemiology of Mycobacterium tuberculosis strains isolated from different regions of Italy and Pakistan

The use of the (GTG)5 oligonucleotide, a repetitive marker in the Mycobacterium tuberculosis chromosome, as a primer in association with an IS6110 outlooking primer has been successfully applied to a PCR-based fingerprinting method. This method classified 62 strains of M. tuberculosis, isolated from human immunodeficiency virus-seropositive and -seronegative patients in different regions of Italy and Pakistan, as having 53 different patterns. The results were compared with traditional IS6110 fingerprinting, by which 47 distinct patterns were observed.

Search for the presence of six Mycoplasma species in peripheral blood mononuclear cells of subjects seropositive and seronegative for human immunodeficiency virus

The prevalence of Mycoplasma fermentans, Mycoplasma pirum, Mycoplasma genitalium, Mycoplasma pneumoniae, Mycoplasma hominis, and Mycoplasma penetrans was investigated by using specific PCR assays with peripheral blood mononuclear cells from subjects infected or not infected with the human immunodeficiency virus (HIV). Only M. fermentans was detected in 5.8% of 154 HIV-seropositive and 11.1% of 90 HIV-seronegative subjects.

IgA and IgG antibodies to distinct serotypes of Mycobacterium avium in HIV seropositivity and AIDS

IgA and IgG antibodies to cytoplasmic and secreted antigens of serotypes 4 and 8 of Mycobacterium avium and the percentage of agalactosyl immunoglobulin (%Gal[0]) were measured by ELISA in groups of blood donors, HIV seronegative persons, HIV seropositive persons with CD4+ cell counts >300/mm3 and AIDS patients co-infected with M.avium. No differences were found between the control groups, but HIV seropositive persons were distinguished by their increased %Gal[0] (p<0.001) and increased IgA titre (p<0.05) to secreted antigens of both serotypes of M. avium. Patients going on to develop aviumosis differed from other HIV-positive individuals, having more IgA to secreted antigens of serotype 8 (p<0.03) and more IgG to secreted antigens of both serotypes (p<0.0001), IgA titres fell to both types of antigen from serotype 4 (p<0.01) and sonicate antigen of serotype 8 (p<0.001) and IgG fell to the secreted antigens of serotype 4 (p<0.03). On interpretation of these observations that antibody profiles to M. avium might be used to identify healthy persons at special risk of developing HIV seropositivity, and to identify persons with early AIDS who are likely to develop aviumosis.

[Acid-alcohol-resistant bacilli detected by microscopic analysis of exhaled air from HIV-infected patients: tuberculosis or mycobacteriosis?]

OBJECTIVES

The incidence of atypical mycobacterial infections has increased with the AIDS epidemic. To present, microscopic examinations of airway specimens positive for acid-fast bacteria were highly suggestive of tuberculosis. However, since the AIDS epidemic, certain authors have reported an increase in Mycobacterium avium intracellulare found in respiratory specimens. The aim of this work was to determine what factors might distinguish between these two infections revealed discovery of an acid-fact bacilli.

METHODS

Hospital files of all HIV seropositive patients seen between November 1992 and March 1995 and with at least one airway specimen positive for acid-fast bacilli were studied retrospectively.

RESULTS

Mycobacterium tuberculosis was isolated in 19 patients, Mycobacterium avium intracellulare in 8 and culosis and M. avium intracellulare. There was no difference for age, sex, geographical origin, transmission mode, antigen positivity, radiologic findings or clinical signs between patients with the different types of mycobacterium. The CD4 count was however significantly lower in patients with an atypical mycobacteriosis (14.5/mm3) than in patients with tuberculosis (91.7 +/- 83.7) (p = 0.004).

CONCLUSION

These findings show that in HIV-infected patients with a CD4 count under 100/mm3, the presence of acid-fact bacilli can indicate either M. tuberculosis or M. avium intracellulare. Combined anti-tuberculosis and antimycobacteriosis therapy thus would appear to be justified until the germ can be identified.

Karyotyping of fluconazole-resistant yeasts with phenotype reported as Candida krusei or Candida inconspicua

The yeasts Candida krusei and Candida inconspicua have similar phenotypes, which may make discrimination of these organisms difficult. In this study we determined the karyotypes of 51 isolates of these two yeast species by contour-clamped homogeneous electric field electrophoresis. We found that the 43 isolates that had the C. krusei phenotype had three karyotype-specific characteristics. These isolates produced either two or three bands between 2,000 and 3,000 kb and no band between 1,300 and 2,000 kb, and there was either a single bright band at 1,300 or 1,200 kb or two separate bands at 1,300, 1,200, or 1,100 kb. Using this technique, we were able to distinguish 27 different C. krusei types on the basis of band variations. The seven isolates identified as C. inconspicua on the basis of phenotype differed in that they produced at least one band between 1,300 and 2,000 kb. These isolates produced six to nine bands, in contrast to C. krusei strains, which produced three to six bands. The MIC of fluconazole for all of the isolates was at least 12.5 mg/liter, as determined by a broth dilution method.

Rhodococcus equi infection in HIV-positive subjects: a retrospective analysis of 24 cases

Rhodococcus equi causes a rare infection in immunocompromised hosts. We describe 24 cases of infection in patients with AIDS-related complex (ARC)/acquired immunodeficiency syndrome (AIDS). Pneumonia was always the first manifestation of R. equi infection, but extrapulmonary involvement was also observed. The main sources of bacteria were sputum, bronchial washings and blood. The strains isolated were mainly susceptible to erythromycin, vancomycin, teicoplanin, rifampicin, imipenem and aminoglycosides. Initial treatment should involve an intravenously administered antibiotic combination therapy including imipenem or vancomycin or teicoplanin, followed by orally administered maintenance combination therapy. Drug combinations should be investigated for serum bactericidal activity in vitro. Surgery does not increase survival time and should only be performed in cases that do not respond to antibiotic treatment. Presumptive risks of infection (contact with horses or farm dust, or cohabiting with people affected by R. equi infection) were present in more than 50% of patients. This finding, and the frequency of bacteria in the sputum, are not sufficient proof of transmission between humans, but do suggest the need for respiratory isolation of patients affected by R. equi pneumonia.

Infective endocarditis in injection drug users: importance of human immunodeficiency virus serostatus and degree of immunosuppression

Human immunodeficiency virus (HIV)-infected patients are at increased risk for serious and recurrent bacterial infections. We hypothesized that the degree of immunosuppression may play an important role in outcomes for HIV-seropositive patients with infective endocarditis (IE). To test our hypothesis, we retrospectively reviewed 144 cases of IE in injection drug users. One hundred two patients with documented HIV status (45 HIV-seropositive patients and 57 HIV-seronegative patients) were included in the analysis. Eleven patients (6 HIV-seropositive patients and 5 HIV-seronegative patients) died in the hospital. Staphylococcus aureus, the most common etiologic pathogen causing IE in our series, was isolated from 32 HIV-seropositive patients (71.1%) and 32 HIV-seronegative patients (56.1%). A clear inverse correlation between mortality rate and CD4 cell count was demonstrated (r = -.625; P < .001). Both univariate and multivariate analyses supported the finding of significantly higher mortality rates among patients with CD4 cell counts of < 200/mm3 than among patients with CD4 cell counts of > 500/mm3 (OR, 14.7; 95% CI, 2.64-81.9).

Altered in vitro handling of Mycobacterium avium complex by monocytes and serum from HIV(+) patients

In patients with acquired immunodeficiency syndrome (AIDS), mycobacterial diseases are leading opportunistic infections. The reasons for the peculiar propensity for disseminated infection with Mycobacterium avium complex (MAC) remain unclear. We have previously examined, in detail, the ability of monocytes from healthy donors to take up and kill MAC under both nonopsonic and opsonic conditions. We have now evaluated the in vitro ability of peripheral blood monocytes from HIV(+) patients to take up and kill MAC organisms, and have discovered a reduced ability under both nonopsonic and opsonic conditions. This reduction is due to: 1) apparent defect(s) in the phagocytes themselves, and 2) substance(s) in the HIV(+) serum which actively suppresses phagocyte activity.

Mycobacterial infection in HIV seropositive and seronegative populations, 1987-93

BACKGROUND

Although the causes of the worldwide resurgence of tuberculosis are multifactorial, the HIV epidemic is believed to have had a central role. Control is further threatened by the emergence of multidrug-resistant tuberculosis.

METHODS

A retrospective evaluation was undertaken of trends in pulmonary and extrapulmonary culture positive mycobacterial pathology, and the prevalence of drug-resistant tuberculosis in both HIV seropositive and, presumptively, HIV seronegative patients receiving their clinical care at St Mary's Hospital, London. Five hundred and thirty eight patients (188 of whom were known to be HIV seropositive) with positive mycobacterial isolates between January 1987 and March 1993 were identified from laboratory records. These were cross referenced with drug surveillance records.

RESULTS

Overall, between 1987 and 1992 there was a progressive 3.5 fold increase in positive mycobacterial isolates and a 2.5 fold increase in patients with proven mycobacterial infection. This increase was greater within the HIV seropositive population. A total of 663 positive mycobacterial isolates was evaluated; the major pathogen identified was Mycobacterium tuberculosis (379 isolates, 57%). Three hundred and fourteen patients were diagnosed as having M tuberculosis, 49 of whom were HIV seropositive. M tuberculosis was predominantly isolated from the lung. Of 358 positive cultures for M tuberculosis (68 HIV seropositive, 290 presumptively HIV seronegative), only 27 isolates (7.6%), almost exclusively derived from presumed HIV seronegative patients, were resistant to either isoniazid, rifampicin, or both drugs together. No increases in drug-resistant isolates were observed over this period.

CONCLUSIONS

There has been a considerable increase in the incidence of tuberculosis in both HIV seronegative and seropositive populations during the study period. The emergence of drug-resistant tuberculosis was not observed.

Bacteriology of sinusitis in human immunodeficiency virus-positive patients: implications for management

The bacteriology of sinusitis in human immunodeficiency virus (HIV)-infected patients has been only sporadically reported. In this study, we report the results of cultures taken from 12 HIV patients with refractory chronic sinusitis who underwent surgery. Nine of the 12 patients had positive cultures with 16 isolates and 5 patients having multiple isolates. Five of the 12 patients grew out atypical or opportunistic infections not responsive to standard medical therapy, including 3 patients with cytomegalovirus, 1 with Aspergillus fumigatus, and 1 with Mycobacterium kansasii. These results suggest the need for aggressive medical care for HIV-infected patients with sinusitis and early intervention for tissue cultures in patients who do not respond to standard antibiotic regimens.

Adherence of Malassezia isolates to human keratinocytes in vitro--a study of HIV-positive patients with seborrhoeic dermatitis

Adherence of Malassezia yeast cells to human keratinocytes was assessed by a novel technique using double-sided Sellotape. Although adherence using double-sided Sellotape is still merely a model for in vivo adherence, it approximates to the conditions found on the skin surface. There were no differences in adhesive properties to human keratinocytes between Malassezia strains originating from HIV-positive and HIV-negative patients with seborrhoeic dermatitis, nor was there a relationship between the severity of seborrhoeic dermatitis and in vitro adherence to human keratinocytes.

Detection of Cryptococcus neoformans capsular polysaccharide antigen in asymptomatic HIV-infected patients

Serum samples from 242 HIV-positive persons were studied for the detection of capsular polysaccharide antigen of Cryptococcus neoformans; 193 of these patients presented less than 300 CD4+ cells/microliters of blood and 49 patients had more than 300 CD4+ cells/microliters. None of them had symptoms or signs characteristic of cryptococcosis. The capsular antigen of C. neofarmans was detected by latex agglutination technique with pronase pretreatment (IMMY, Crypto-Latex Antigen Detection System, Immunomycologics Inc., OK, USA); in 61% of the samples, ELISA technique was also used (Premier, Cryptococcal Antigen, Meridian Diagnostic Inc., Cincinnati, Oh, USA). The comparative study of both methods showed that the results obtained were similar in 96.9% of the cases. The capsular antigen was detected in 13 out of 193 (6.7%) patients with less than 300 CD4+ cells/microliters. Cryptococcosis was confirmed mycologically in 3 of these 13 cases (23%) by the isolation of C. neoformans in CSF or blood cultures. Three patients, who had presented negative results of both tests for capsular antigen, suffered disseminated cryptococcosis 4 to 8 months later. The predictive diagnostic value of capsular antigen detection of C. neoformans seems to be low and we believe that it should not be done routinely in asymptomatic HIV-positive persons.

Detection of mycobacteria in bone marrow biopsy specimens taken to investigate pyrexia of unknown origin

AIMS

To investigate the value of bone marrow biopsy in the diagnosis of mycobacterial infection.

METHODS

The culture results of 433 bone marrow samples taken between 1983 and 1992 were reviewed. The histopathology reports on bone marrow trephine specimens of culture positive samples and all those on HIV positive patients sent in 1992 were also reviewed.

RESULTS

Fifty one specimens yielded Mycobacterium spp, 47 were obtained from HIV positive patients. Of the isolates, 42 were Mycobacterium avium-intracellulare (MAI), five were M tuberculosis (MTB), and the remaining four comprised a variety of atypical mycobacteria. All MAI positive samples were obtained from HIV positive patients, with the bone marrow being the only culture positive specimen in one third. Bone marrow yielded MTB only in patients from whom it was also isolated in other specimens. Eleven of 47 trephine specimens from positive bone marrow showed granulomata and nine showed acid-fast bacilli. No acid-fast bacilli were seen in the absence of granulomata.

CONCLUSION

Bone marrow biopsy for mycobacterial culture should be reserved for severely immunosuppressed patients and should not be advocated for immunocompetent patients with suspected tuberculosis. Bone marrow biopsy still has a role in the investigation of pyrexia of unknown origin in HIV positive patients, despite the advent of mycobacterial blood culture techniques, particularly if these can be processed safely in automated systems.

Comparison of periodontal disease in HIV seropositive subjects and controls (II). Microbiology, immunology and predictors of disease progression

The aims of this study were to compare the prevalence of suspected periodontal pathogens in subgingival plaque from 29 HIV seropositive and 27 control subjects and to determine the association of these bacteria with periodontal destruction. Subgingival plaque was collected from the mesiobuccal sites of all teeth, except 3rd molars. Bacteria were identified and enumerated using non-isotopic whole chromosomal DNA probes and a colony lift method. At baseline, HIV seropositive subjects had significantly higher mean % of Porphyromonas gingivalis than control subjects. This difference could be attributed to a subgroup of HIV seropositive subjects with widespread attachment loss. No correlations were observed between the mean %s of DNA probe species and mean attachment loss, CD4 and CD8 T lymphocyte counts or CD4: CD8 ratio. No significant microbiological differences were detected between active and control sites in HIV seropositive subjects on a longitudinal basis. There appeared to be an inverse relationship between the mean %s of P. gingivalis and V. parvula, with respect to progression of HIV infection. The ability of microbiological parameters to predict site-specific breakdown in HIV seropositive subjects requires further investigation.

Analysis of antral biopsy specimens for evidence of acquired mucosa-associated lymphoid tissue in HIV1-seropositive and HIV1-negative patients

BACKGROUND

There is conflicting evidence concerning the prevalence of Helicobacter pylori gastritis in HIV1-infected patients. Furthermore, a possible influence of immunodeficiency on the acquisition of mucosa-associated lymphoid tissue (MALT) in the antral mucosa remains to be elucidated.

METHODS

Seventy-seven consecutive HIV1-infected patients (mean age, 40.2 years) were compared in a prospective study with 77 HIV1-negative age-matched patients, using immunohistochemical stainings.

RESULTS

In HIV1-infected patients the prevalence of H. pylori gastritis was lower and the inflammatory reaction less pronounced than in controls. Lymphoid follicles and intraepithelial B cells were significantly more often detected in HIV1-negative patients.

CONCLUSIONS

Evidence of acquired MALT is only rarely found in HIV1-infected patients. These findings might contribute to the explanation of why low-grade gastric MALT lymphomas have not been reported in HIV1-infected patients so far.

HEp-2 cell-adherent Escherichia coli in patients with human immunodeficiency virus-associated diarrhea

Diarrhea occurs commonly in African human immunodeficiency virus (HIV) infections. A case-control (HIV-positive vs. -negative) study of adults with diarrhea was done in Lusaka, Zambia, to determine the prevalence of intestinal infection by HEp-2 cell-adherent Escherichia coli. Adherent E. coli were more common in HIV-positive patients with acute diarrhea than among HIV-negative controls (60% vs. 33%) and were found significantly more often in HIV-positive patients with chronic diarrhea than among HIV-negative controls with chronic diarrhea (79% vs. 17%, P < .002). Adherent strains were found significantly more often among HIV-positive patients (69%) than in 22 asymptomatic subjects (36%, P < .02). The HEp-2 cell adherence of the E. coli strains did not show a common pattern. Adherent bacteria were also observed in colonic biopsies from 32% of Zambians with chronic diarrhea who underwent endoscopy. Adherent E. coli may be an important cause of HIV-associated diarrhea in Zambia.

Single-strand conformation polymorphism study of human immunodeficiency virus type 1 RNA and DNA in plasma, peripheral blood mononuclear cells, and their virologic cultures

Single-strand conformation polymorphism (SSCP) analysis was applied to human immunodeficiency virus type 1 (HIV-1) nucleic acids in plasma and peripheral blood mononuclear cells (PBMC) from 16 patients and to 15 PBMC cocultures and 6 plasma cultures prepared from the specimens. Two hypervariable regions were analyzed: in the gag gene and part of the V3 loop. Random paired matching of SSCP patterns between HIV-1 RNA and provirus DNA was tested, from plasma and PBMC from the same blood specimen, supernatant and PBMC from the same PBMC coculture, supernatant and PBMC from the same plasma culture, provirus DNA in cocultured PBMC and the PBMC inoculum, and HIV-1 RNA in a plasma culture supernatant and in the plasma inoculum. Paired matching was nonrandom for both regions in the first three situations and for gag in the fourth, with P < or = .01; matching was random for gag in the last situation. The HIV-1 env target region produced in culture diverged from that in the inoculum in 18 of 21 instances.

DNA fingerprinting and phenotyping of Mycobacterium tuberculosis isolates from human immunodeficiency virus (HIV)-seropositive and HIV-seronegative patients in Tanzania

With the purpose of determining whether the risk of infection with a particular clone of Mycobacterium tuberculosis is influenced by the human immunodeficiency virus (HIV) status of the host, we analyzed and compared 68 mycobacterial isolates obtained from HIV-seropositive patients with tuberculosis (TB) in Dar es Salaam, Tanzania, with 66 mycobacterial isolates obtained from HIV-seronegative patients with TB in the same geographical region by using both DNA fingerprinting and classical phenotyping methods. One hundred one different IS6110 fingerprinting patterns were observed in the 134 isolates. The level of diversity of the DNA fingerprints observed in the HIV-seropositive group was comparable to the level of the diversity observed in the HIV-seronegative group. Resistance to a single anti-TB drug was found in 8.8% of the tested isolates, and 3.2% of the isolates were resistant to more than one anti-TB drug. The drug susceptibility profiles were not significantly difference between the two groups of isolates compared in the present study. Phenotypic characteristics which classify M. tuberculosis strains as belonging to the Asian subgroup correlated with a low IS6110 copy number per isolate. However, the occurrence of Asian subgroup strains was not associated with the HIV status of the patients. The results of the study suggested an equal risk of infection with a defined M. tuberculosis clone for HIV-seropositive and HIV-seronegative individuals.

Development of a new selective plating medium for Rhodococcus equi

A new selective plating medium for Rhodococcus equi containing ceftazidime (20 mg/l) and novobiocin (25 mg/l) on a Mueller-Hinton agar basis is described. It proved to be less inhibitory for R. equi than selective plating media devised earlier and grew only very few other nocardioform bacteria.

Syncytium-inducing (SI) phenotype suppression at seroconversion after intramuscular inoculation of a non-syncytium-inducing/SI phenotypically mixed human immunodeficiency virus population

Two distinct biological phenotypes of human immunodeficiency virus (HIV) have been described: the non-syncytium-inducing (NSI) phenotype, best characterized by the inability to infect MT-2 cells, and the syncytium-inducing (SI) phenotype, with the ability to infect MT-2 cells. The earliest virus population observed following HIV transmission is generally of the NSI phenotype, even after exposure to inocula of mixed NSI/SI phenotype. In this study, the issue of intrapatient selection of virus phenotype following transmission was addressed by studying two cases of accidental transmission. A comparison of the sequences of the V1-V2 and the V3 coding regions of the envelope gene and the p17 region of the gag gene showed that the donor-recipient pairs were tightly clustered in all gene segments, but away from local and published transmission controls. The intrasample variation of the p17 sequence was greater in the recipients and smaller in the donors than that of the V3 region sequence, indicating selection of V3 at transmission. In these transmission cases, the effects of an intravenous inoculation of a small quantity of blood containing predominantly SI V3 sequences (6 of 8 clonal sequences) were compared with those of an intramuscular inoculation of a large quantity of blood containing predominantly NSI viruses (14 of 16 clonal sequences). Both SI and NSI V3 regions were demonstrated to be phenotypic expressions of genetically related viral strains. The inoculation of the predominantly SI virus population resulted in the persistence of an SI virus population in the recipient and a rapid CD4+ T-cell decline. The inoculation of the predominantly NSI population resulted in a selective amplification of SI viruses before seroconversion, followed by a suppression of SI viruses at seroconversion and a rapid decline of CD4+ T-cell numbers. These data suggest that the suppression of SI viruses can be accomplished following the development of HIV-specific immunity and that the ability to suppress SI viruses does not prevent the development of immunodeficiency.

A simple quantitative culture of Malassezia spp. in HIV-positive persons

BACKGROUND

Etiological role of Malassezia spp. remains controversial in certain skin diseases.

OBJECTIVE

To adapt a 'tape method' for quantitative culture of Malassezia spp.

METHOD

Samples for culture were taken from clinically normal forehead skin of HIV-positive and negative persons by stripping with a tape that was then placed on Leeming & Notman medium. The number of colonies was counted after 14 days.

RESULTS

74/78 (94.8%) cultures were positive, for a median count of 9 CFU/tape (range 0 to > 200). High skin density of Malassezia spp., defined as more than 100 CFU/tape, was found in 7/38 (18.4%) HIV-positive persons and was absent (0/40) in the HIV-negative group (p < 0.01).

CONCLUSION

The method used is simple, unexpensive and reliable. High Malassezia spp. density was only found in HIV-positive patients.

Nasopharyngeal carriage of Staphylococcus aureus and carriage of tetracycline-resistant strains associated with HIV-seropositivity

The aim of this prospective study was to investigate the relationship between carriage of antibiotic-resistant Staphylococcus aureus and infection with the human immunodeficiency virus (HIV). A total of 554 pernasal swabs was taken during a six-month period from 554 adult patients attending three outpatient clinics and from inpatients from a hospital in Nairobi, Kenya. Overall, 121 swabs (22%) yielded Staphylococcus aureus, there being significantly higher carriage in HIV-positive patients (71/264, 27%) than in HIV-negative patients (50/290, 17%); p = 0.008. Antimicrobial resistance rates were determined for 110 isolates and were high for penicillin (91%) and tetracycline (72%) and low for erythromycin (8%), methicillin (3%), gentamicin (5%) and chloramphenicol (0%). Genetic analysis showed plasmids in the range of 24-42 MDa to be associated with beta-lactamase production and plasmids in the range of 3-5 MDa to be associated with resistance to tetracycline, erythromycin and trimethoprim. All nine erythromycin-resistant strains were from HIV-positive patients (p = 0.02). There was a significant association of tetracycline resistance with HIV seropositivity (p = 0.002). The association of HIV seropositivity with Staphylococcus aureus carriage and carriage of antibiotic-resistant strains against the background of the HIV epidemic are of relevance in individual patient care and raise concern for public health.

The biological phenotype of HIV-1 is usually retained during and after sexual transmission

The biological phenotype of HIV-1 isolates from 21 subjects with primary HIV-1 infection was determined in primary lymphocytes and monocyte-derived macrophages as well as in three T-cell lines (MT-2, HUT78, and C8166). Seven isolates (33%) replicated on at least one cell line and were classified as rapid/high (n = 6) or intermediate (n = 1), while 14 isolates (67%) did not replicate in cell lines and were classified as slow/low. All isolates replicated in primary monocyte-derived macrophage cultures. Studies on 10 pairs consisting of index case and seroconverting sexual partner showed that the biological phenotype of HIV-1 was unchanged in nine transmissions, including 5 pairs where a rapid/high virus was transmitted. Most individuals (5 of 6) infected by a rapid/high virus retained this phenotype after seroconversion. These individuals also had significantly lower CD4 lymphocyte counts 1-3 years after infection. Thus, in contrast to what has been suggested by others, we found that HIV-1 variants with rapid/high phenotype were usually not suppressed, neither during sexual transmission nor after seroconversion in the new host. These findings have important implications for the understanding of HIV-1 transmission and pathogenesis as well as for vaccine design.

Optimum recovery of Mycobacterium avium complex from blood specimens of human immunodeficiency virus-positive patients by using small volumes of isolator concentrate inoculated into BACTEC 12B bottles

Recovery of Mycobacterium avium complex organisms from 412 lysis-centrifugation (Isolator) concentrates of blood specimens obtained from human immunodeficiency virus-positive individuals was attempted with the following media (and Isolator concentrate inoculum volumes): BACTEC 12B broth (0.2 and 1.0 ml), Lowenstein-Jensen slants (0.1 ml), and Middlebrook 7H10/11 agar (0.1 ml). A total of 42 M. avium complex isolates were recovered. The highest rates of recovery and shortest detection times were noted with BACTEC 12B bottles inoculated with 0.2 ml of Isolator concentrate. Middlebrook agar was superior to Lowenstein-Jensen slants. Fluorochrome acid-fast smears performed directly upon Isolator concentrates were of no utility.

The natural history of HIV-1 infection: virus load and virus phenotype independent determinants of clinical course?

Virus load and virus phenotype have both been indicated as major determinants of disease progression in HIV-1 infection. In this study HIV-1 RNA copy numbers in serum, virus phenotype, and CD4+ cell counts were analyzed longitudinally in a group of 20 seroconverters progressing to AIDS within 5.5 years. In this group 12 individuals developed AIDS without syncytium-inducing (SI) viruses ever being isolated, while 8 individuals showed a non-SI (NSI) to SI phenotypic switch prior to AIDS development. HIV-1 RNA copy numbers in sera of all progressors were stable and high from seroconversion until development of AIDS. Twenty-one seroconverters remaining asymptomatic for more than 5.5 years were selected as nonprogressing controls, and both progressors and nonprogressors were evaluated at seroconversion and early in infection (3 years post seroconversion). Comparative analysis revealed that at the point of seroconversion HIV-1 RNA copy numbers in sera from NSI progressors, SI progressors, and nonprogressors were not significantly different, nor were their CD4+ cell counts. At seroconversion all individuals harbored viruses with an NSI phenotype. In contrast to the progressors, HIV-1 RNA copy numbers in sera of nonprogressors had declined significantly during the early period of infection. At the second time point RNA copy numbers in the sera of NSI progressors and nonprogressors differed significantly (P = 0.0005), while RNA copy numbers in the sera of SI progressors and nonprogressors did not. However, at this time point the CD4+ cell counts of SI progressors were significantly lower than those from nonprogressors (P = 0.002), while the CD4+ cell counts of NSI progressors and nonprogressors did not differ significantly. These results show that early in HIV-1 infection progressors and nonprogressors are distinguishable. NSI progressors can be distinguished from nonprogressors on the basis of serum HIV-1 RNA load and S1 progressors on the basis of CD4+ cell decline. In addition, a significant decrease in the number of HIV-1 RNA copies in the early phase of infection seems to postpone the development of AIDS.

Quantification of human immunodeficiency virus type 1-infected mononuclear cells in peripheral blood of seropositive subjects by newly developed flow cytometry analysis of the product of an in situ PCR assay

The presence of human immunodeficiency virus type 1 (HIV-1) proviral DNA in peripheral blood mononuclear cells (PBMC) of three groups (group 1, more than 500 CD4+ T cells per microliter; group 2, between 200 and 499 CD4+ T cells per microliter; group 3, fewer than 200 CD4+ T cells per microliter) of HIV-1-infected patients, in different stages of the disease, was determined by using a newly developed flow cytometry analysis of the product of in situ PCR assay and compared with other markers of viral replication (HIV-1 p24 antigenemia and viral isolation). Results showed varied percentages of HIV-1-infected PBMC, ranging from 0.6 to 20%. Patients with more than 500 CD4+ T cells per microliter showed the lowest percentage of HIV-1-infected PBMC (2.1 +/- 1.7), compared with patients with CD4+ T-cell counts of between 200 and 499 per microliter (6.5% +/- 4.1%; P < 0.001) and patients with fewer than 200 CD4+ T cells per microliter (4.9% +/- 4.7%; P < 0.05). The difference in the percentage of HIV-1-infected PBMC between group 2 and group 3 patients may in part reflect the loss of CD4+ T lymphocytes in more advanced stages of the disease. However, the results clearly indicate a striking coincidence between the fall of the CD4+ T-cell count below 400/microliter and the sharp increase in PBMC virus loading and p24 antigenemia. Since the procedure is relatively easy to perform, it could be used to monitor the evolution of HIV-1 infection and may prove a useful adjunct in tailoring therapeutic strategies.

Routine analysis of induced sputum is not an effective strategy for screening persons infected with human immunodeficiency virus for Mycobacterium tuberculosis or Pneumocystis carinii. Pulmonary Complications of HIV Infection Study Group

A prospective multicenter cohort study comprising 1,171 individuals who were seropositive for human immunodeficiency virus (HIV) but did not have AIDS at the time of enrollment and 182 HIV-seronegative controls, was studied by means of routine induced-sputum analysis in an attempt to detect occult tuberculosis or Pneumocystis carinii pneumonia. One occult case of tuberculosis was discovered upon the patient's enrollment (at baseline); none were discovered during follow-up. Two additional Mycobacterium tuberculosis isolates were recovered (one at baseline, one during follow-up) from subjects with symptoms or abnormalities evident on chest roentgenograms. Three specimens were false-positive (one for M. tuberculosis, two for P. carinii). Five pathogenic nontuberculous mycobacteria isolates were recovered during follow-up. Nonpathogenic, nontuberculous mycobacteria were recovered from 51 (4.6%) of 1,113 baseline specimens and 56 (3.7%) of 1,518 follow-up specimens, primarily at a center where the water supply was contaminated. We conclude that routine induced-sputum analysis is not an effective strategy for screening HIV-infected asymptomatic subjects for tuberculosis or P. carinii pneumonia before the onset of clinically recognizable disease activity.

Deficiency in antibody response to human cytomegalovirus glycoprotein gH in human immunodeficiency virus-infected patients at risk for cytomegalovirus retinitis

Human immunodeficiency virus (HIV)-infected patients at risk for symptomatic human cytomegalovirus (CMV) infection were studied for serum antibody to CMV glycoproteins gH and gB. Antibody titers to gB in HIV-seropositive patients, irrespective of CD4 cell counts or presence of CMV retinitis, were significantly higher than titers in HIV-seronegative, CMV-seropositive patients but were comparable to titers detected in HIV-seronegative patients with CMV mononucleosis. In contrast, antibody to gH was rarely detected in HIV-seropositive patients with CD4 cell counts > 100/mm3 compared with patients with counts > 100/mm3. The inability to detect gH antibody at a time of high risk for symptomatic CMV retinitis suggests that immune intervention with either gH-specific vaccine or passive immunotherapy may benefit HIV-infected persons at risk for symptomatic CMV disease.

Relationship between fluconazole sensitivity of Candida albicans isolates from HIV positive patients and serotype, adherence and CD4+ lymphocyte count

The sensitivity of fluconazole, serotype and adherence to buccal epithelial cells of 46 Candida albicans isolates was studied in vitro. Strains were isolated from 18 HIV-positive patients with variable CD4+ lymphocyte counts who were receiving long-term fluconazole therapy. Results showed that sensitivity to fluconazole correlated with serotype. Of the sensitive isolates 81.5% were serotype A and 18.5% serotype B, whereas of the resistant isolates 37.5% were serotype A and 62.5% serotype B. Sensitivity to fluconazole also correlated with adherence capacity, resistant isolates showing slightly less adherence to buccal epithelial cells than sensitive isolates. Weakly adherent isolates represented 87% of resistant isolates and only 63% of sensitive isolates. Resistant strains were isolated in highly immunocompromised patients. All strains isolated in patients with CD4+ lymphocyte counts above 200 lymphocytes/microliters were sensitive, whereas intermediate and resistant strains were isolated in patients with counts below 200 lymphocytes/microliters. Statistical analyses showed no correlation between adherence of isolates to buccal epithelial cells and CD4+ lymphocyte counts.

Differentiation between human immunodeficiency virus type 1 (HIV-1) and HIV-2 isolates by nonradioisotopic reverse transcriptase-typing assay

We tested whether human immunodeficiency virus type 1 (HIV-1) could be differentiated from HIV-2 by a reverse transcriptase (RT)-typing assay that measured the reduction of enzyme activity owing to specific antibody. RT-inhibiting antibody was examined for HIV type specificity by a new nonradioisotopic RT assay. Antibodies from four rabbits immunized with recombinant HIV-1 RT and from 23 HIV-1-seropositive individuals all specifically inhibited the enzyme activities of two HIV-1 strains (LAV-1 and GH-3), three zidovudine-resistant HIV-1 mutants, and a recombinant HIV-1 RT. However, none of these antisera affected the activities of six HIV-2 strains (GH-1, GH-2, GH-4, GH-5, GH-6, LAV-2ROD), Rous-associated virus type 2, and DNA polymerase I from Escherichia coli. In contrast, HIV-2 antibody from a rabbit immunized with disrupted GH-1 virions blocked the enzyme activities of the six HIV-2 strains but not those of the three HIV-1 strains, Rous-associated virus type 2, or DNA polymerase I. These results indicate that the antigenic domains of HIV-1 and HIV-2 RTs recognized by their inhibiting antibodies are distinct from each other and are highly conserved. Clinical HIV isolates from 18 HIV-1-seropositive individuals and 3 HIV-2-seropositive Ghanaian individuals were identified as HIV-1 and HIV-2, respectively, by the nonradioisotopic RT-typing assay.

Clostridium difficile-associated diarrhea in patients with HIV positivity and AIDS: a prospective controlled study

OBJECTIVE

To compare the clinical manifestations and therapeutic responses of Clostridium difficile infection in HIV-infected and noninfected individuals.

METHODS

Patients were identified for this study if they had C. difficile toxin in the stool. The patients were then followed prospectively by the investigators. All patients were treated with a standard regimen, and clinical and laboratory findings were recorded. Persistence and resolution or recurrence of symptoms and complications were recorded.

RESULTS

A total of 87 patients were studied, of which 12 were HIV positive, 20 had AIDS, and 55 had no known HIV infection. The AIDS group was younger and had a lower total leukocyte count than the controls. There were no statistically significant differences in temperature, leukocytosis, clinical symptoms, therapeutic response, or recurrence or persistent of symptoms.

CONCLUSIONS

Despite the immunosuppression of HIV infection, C. difficile infection behaves no differently in HIV/AIDS patients than it does in controls.

Human immunodeficiency virus type 1 variants with increased replicative capacity develop during the asymptomatic stage before disease progression

We examined the replicative properties of a series of sequential isolates and biological clones of human immunodeficiency virus type 1 (HIV-1) obtained from an individual who progressed from seroconversion to AIDS in approximately 5 years. HIV-1 isolated soon after seroconversion replicated slowly and to low levels in cultures of peripheral blood mononuclear cells; however, subsequent isolates obtained during asymptomatic infection showed a marked increase in replication kinetics. This was examined in more detail by using a panel of 35 biological clones of HIV-1 generated from sequential patient peripheral blood mononuclear cell samples. Each clone was evaluated for replication in primary macrophages and CD4+ T lymphocytes and for the ability to induce syncytium formation in MT-2 cell cultures. Consistent with earlier observations, we found that all of the clones isolated just after seroconversion were slowly replicating and non-syncytium inducing (NSI). However, NSI variants with increased replication kinetics in macrophages were identified soon thereafter. These variants preceded the appearance of NSI and syncytium-inducing variants, with rapid replication in both macrophages and CD4+ T lymphocytes. To determine whether changes in the rate of replication could be traced to the early stages of the virus life cycle, PCR assays were used to evaluate entry and reverse transcription of selected biological clones in macrophages and CD4+ T lymphocytes. We found there was no inherent block to entry or reverse transcription for the slowly replicating variants; however, this does not preclude the possibility that small differences in the rate of entry may account for larger differences in the replication kinetics over many cycles. Overall, our results demonstrate that rapidly replicating variants of HIV-1 emerge during the asymptomatic period in a patient who subsequently progressed clinically, suggesting that these variants may play an important role in HIV-1 pathogenesis.

Rapid detection of mycobacteria by combining a radiometric detection system with DNA probes

Forty-four Mycobacterium-spp. were isolated in 33 patients from an infectious diseases ward. All patients were HIV-positive and most of them were drug-abusers. M. avium-intracellulare was the most common type of MOTT (Mycobacteria other than tuberculosis) detected and the only microorganism isolated in patients with mycobacteriaemia. The radiometric method performed by the Bactec system enhanced the isolation rate of mycobacteria, especially from the bloodstream. The Gen-probe DNA hybridization system proved to be rapid diagnostic tool for the identification of strains.