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Biomedical subjects

M F Sierra

Publications and source records attributed to M F Sierra.

At least 19 recordsLinked to original sources
PubMed2000

The role of clinical suspicion in evaluating a new diagnostic test for active tuberculosis: results of a multicenter prospective trial.

CONTEXT: In laboratory trials, nucleic acid amplification tests for the diagnosis of tuberculosis (TB) are more accurate than acid-fast bacilli (AFB) smear microscopy and are faster than culture. The impact of these tests on clinical diagnosis is not known. OBJECTIVE: To assess the performance of a nucleic acid amplification test, the enhanced Mycobacterium tuberculosis Direct (E-MTD) test, against a uniform clinical standard stratified by level of clinical suspicion. DESIGN: Prospective multicenter trial conducted between February and December 1996, documenting the clinical suspicion of TB at enrollment and using final comprehensive diagnosis as the criterion standard. SETTING: Six urban medical centers and 1 public health TB clinic. PATIENTS: A total of 338 patients with symptoms and signs consistent with active pulmonary TB and complete clinical diagnosis were stratified by the clinical investigators to be at low (< or =25%), intermediate (26%-75%), or high (>75%) relative risk of having TB. MAIN OUTCOME MEASURES: Sensitivity, specificity, and positive and negative predictive values of the E-MTD test in clinical suspicion of groups with low (n = 224); intermediate (n = 68); and high (n = 46) clinical suspicion of TB. RESULTS: Based on comprehensive clinical diagnosis, sensitivity of the E-MTD test was 83%, 75%, and 87% for low, intermediate, and high clinical suspicion of TB, respectively, and corresponding specificity was 97%, 100%, and 100% (P = .25). Positive predictive value of the E-MTD test was 59% (low), 100% (intermediate), and 100% (high) compared with 36% (low), 30% (intermediate), and 94% (high) for AFB smear. Corresponding negative predictive values were 99%, 91%, and 55% [corrected] (E-MTD test) vs 96%, 71%, and 37% (AFB smear). CONCLUSIONS: For complex diagnostic problems like TB, clinical risk assessments can provide important information regarding predictive values more likely to be experienced in clinical practice. For this series, a clinical suspicion of TB was helpful in targeting areas of the clinical spectrum in which nucleic acid amplification tests can make an important contribution.

Adult↗
PubMed1998

Medical-resource use for suspected tuberculosis in a New York City hospital.

OBJECTIVE: To compare resource use by diagnostic outcome among hospital admissions during which tuberculosis (TB) was suspected. DESIGN: Retrospective study based on chart review and microbiology laboratory data. SETTING: The department of medicine in a municipal hospital serving central Brooklyn, New York. PARTICIPANTS: We identified all adult admissions in 1993 during which TB was suspected. We assigned each admission to one of four mutually exclusive groups defined by the results of microbiological tests (acid-fast bacilli [AFB] smear and culture): culture-positive and smear-positive (C+S+); culture-positive and smear-negative (C+S-); culture-negative and smear-positive (C-S+); or culture-negative and smear-negative (C-S-). Each admission was divided into two separate periods to which the utilization of medical resources was assigned: the diagnostic and the postdiagnostic periods, which were separated by the date of receipt of the first definitive culture report. RESULTS: Data on 519 admissions (93 C+S+; 57 C+S-; 30 C-S+; and 339 C-S-) were analyzed. Although C+S+ were more likely than other groups to have an admitting diagnosis of TB, approximately one quarter of the admissions without TB (C-S+, C-S-) were admitted with the principal diagnosis of TB. For the four groups, C+S+, C+S-, C-S+, and C-S-, the respective rates of TB isolation and anti-TB treatment, and median lengths of isolation were 98%, 87%, and 34 days; 74%, 74%, and 7 days; 83%, 83%, and 15 days; and 44%, 29%, and 0 days. During the diagnostic period, the rate and length of isolation were similar in the AFB-smear-positive groups (C+S+ and C-S+). We estimated that admissions without culture-proven TB (C-S+ and C-S-) accounted for 3,174 (36%) of the 8,712 days of TB isolation expended and for 65% of the 16,671 days of anti-TB treatment. The vast majority of this resource consumption (2,737 [86%] of 3,174 days of isolation) occurred during the diagnostic period before a definitive culture result was known. CONCLUSIONS: Our results suggest that prolonged diagnostic uncertainty and misclassification of cases due to false-positive and false-negative smears are associated with substantial medical-resource consumption. New diagnostic modalities that reduce the period of diagnostic uncertainty could reduce the utilization of resources later found to be unnecessary.

Adult↗
PubMed1997

Pelvic inflammatory disease and human immunodeficiency virus infection.

OBJECTIVE: To identify the effect of human immunodeficiency virus (HIV) infection on the clinical course of pelvic inflammatory disease (PID). METHODS: Women hospitalized with PID at an urban hospital serving a population at high risk for HIV were studied cross-sectionally. Data abstracted from medical records of 349 women, admitted between July 1992 and April 1994 were linked anonymously to HIV serology. Main outcome measures were length of hospital stay, prolonged fever, tubo-ovarian abscess, surgery, and change in antibiotics. RESULTS: Among the 349 women with PID, 27 were HIV-positive. These HIV-positive women had lower mean white blood cell counts at admission (7411 versus 11,266, P < .01), lower mean lymphocyte counts (1411 versus 1928, P < .01), greater febrile morbidity (54 versus 28.3%, P < .01), and longer hospital stays (10.5 versus 6.4 days, P < .01) than HIV-negative women. Women who were HIV-positive required more time for defervescence and needed to change their antibiotic regimen more frequently (41 versus 12.7%, P < .01); differences in tubo-ovarian abscesses (19 versus 14%, P = .52) or surgery (15 versus 6.2%, P = .10) were not significant. The differences in hospital course between HIV-positive and HIV-negative women were modest, and they were resolved largely by the fourth or fifth hospital day. All HIV-positive women were treated successfully with first- or second-line antibiotic regimens. CONCLUSION: Despite more severe initial presentation and a prolonged hospital course, HIV-positive women with PID, but without other acute illnesses, were treated successfully with standard therapeutic regimens. These observations support current recommendations for hospitalization of HIV-positive women with PID and treatment according to current standards.

Adult↗
PubMed1997

Immune compromise and prevalence of Candida vulvovaginitis in human immunodeficiency virus-infected women.

OBJECTIVE: To investigate the effect of human immunodeficiency virus (HIV) infection on vaginal yeast colonization and symptomatic vulvovaginitis and to explore the effects of immune compromise on these conditions in HIV-positive women. METHODS: Between September 1991 and May 1993, 223 HIV-positive women without AIDS-defining conditions were enrolled for prospective follow-up and compared with 289 HIV-negative women enrolled in a concurrent study. Standardized gynecologic assessment was carried out. RESULTS: Cultures from 81 of 223 (36%) HIV-positive women and 72 of 289 (25%) HIV-negative women were positive for any yeast. The most commonly isolated yeasts were Candida albicans and Torulopsis glabrata; the proportion of non-C albicans isolates (26%) did not differ by serostatus. The rates of C albicans colonization and vulvovaginitis among immunocompetent (CD4 count at least 500 cells/mm3) HIV-positive women did not differ from those among HIV-negative women. Among HIV-positive women, risks for colonization and for symptomatic vulvovaginitis were increased approximately threefold and fourfold respectively, in women with CD4 counts below 200 cells/mm3 compared with either immunocompetent HIV-positive women or HIV-negative women. CONCLUSION: The yeast species isolated from HIV-positive and HIV-negative women were similar. Rates of vaginal colonization and vaginitis were similar among nonimmunocompromised HIV-positive women and HIV-negative women. Elevated rates of yeast colonization and vaginitis were not seen among this population of HIV-infected women before immune compromise. Both vaginal colonization and symptomatic vaginitis increased with immune compromise among HIV-positive women, especially at CD4 counts below 200 cells/mm3.

AIDS-Related Opportunistic Infections↗
PubMed1997

Bacteraemia during direct laryngoscopy and endotracheal intubation: a study using a multiple culture, large volume technique.

Bacteraemia secondary to orotracheal intubation has been reported to occur in 0-5.3% of patients. Bacteraemia detection is dependent upon several factors including the volume of blood per culture and the number of cultures. Prior studies used small volumes of blood and one or two cultures, and may therefore have underestimated the incidence of bacteraemia. Sixty-two adult patients who underwent direct laryngoscopy and endotracheal intubation were studied. Baseline blood cultures were sterile in all patients. After intubation, four blood cultures were obtained in ten minutes, with 10 ml being evenly divided between aerobic and anaerobic media. Two patients (3.2%) became bacteraemic. This is a lower incidence than occurs in association with other procedures for which The American Heart Association does not recommend administration of prophylactic antibiotics. Therefore, prophylactic antibiotics are not recommended prior to direct laryngoscopy. However, when a prophylactic antibiotic is administered prior to surgery, it would be best to administer the antibiotic prior to direct laryngoscopy and intubation.

Adult↗
PubMed1996

Factors associated with cytomegalovirus infection among human immunodeficiency virus type 1-seronegative and -seropositive women from an urban minority community.

Cytomegalovirus (CMV) seroprevalence and genital tract shedding in human immunodeficiency virus (HIV)-seronegative and HIV-seropositive women from an urban minority community were investigated. CMV seropositivity was high in both groups: 181 (95.2%) of 190 HIV-negative and 158 (90.3%) of 175 HIV-positive subjects. Cervicovaginal shedding was detected in 8 (4.4%) CMV-positive HIV-negative subjects and 31 (19.6%) HIV-positive subjects (odds ratio [OR], 5.28; P < .001). Multiple logistic regression analysis revealed that CMV shedding was independently associated with younger age (OR = 0.90; P < .001) and concurrent Chlamydia trachomatis or Neisseria gonorrhoeae infection (OR = 3.60; P = .08). However, shedding was observed over a broad age range in HIV-positive subjects, with 54.8% of shedders being > or = 30 years old. Among HIV-positive subjects, CMV shedding was also associated with decreased CD4 cell counts (P = .04) and, compared with HIV-negative subjects, was significantly higher (P < .001) among subjects with CD4 cell counts < 500 x 10(6)/L (26.5% in subjects with counts < or = 200 and 22.1% in subjects with counts of 201-499 x 10(6)/L).

AIDS-Related Opportunistic Infections↗
PubMed1995

Temporal trends and transmission patterns during the emergence of multidrug-resistant tuberculosis in New York City: a molecular epidemiologic assessment.

To ascertain the role of human immunodeficiency virus (HIV) and Mycobacterium tuberculosis transmission on multidrug-resistant (MDR) tuberculosis (TB) emergence in New York City, medical records, drug susceptibilities, and restriction fragment length polymorphisms (RFLPs) of TB cases at a city hospital between two 9-month periods (1987-1988 and 1990-1991) were reviewed. The proportion of TB patients with MDRTB increased from 10% (27/267) to 17% (38/222; P = .03). Among MDRTB patients of known HIV status, the proportion with HIV increased from 16% (3/19) to 58% (22/38; P = .006). HIV-infected MDRTB patients were more likely than the seronegative ones to have initial MDRTB (88% vs. 56%; P = .03). Among 56 MDR cases with RFLP results, 12 had unique patterns; 44 belonged to one of six clusters. During 1990-1991, 27 (75%) of 36 MDRTB patients were infected with strains isolated from HIV-seronegative patients during 1987-1988. The increase in MDRTB caused by transmission from immunocompetent to immunocompromised persons underscores the urgency of TB control in populations with increasing HIV prevalence.

Adolescent↗
PubMed1995

Mucocutaneous fungal colonization in HIV-infected children.

The prevalence of symptomatic mucocutaneous candidiasis in HIV-infected children is well documented. Information, however, of the carriage rate of potential fungal pathogens is lacking. In this study we determined the fungal colonization rate of multiple mucocutaneous sites from 13 HIV-infected and 12 control children. The rate of yeast and mould colonization and the species of fungal isolates were essentially the same for both groups of patients. However, several HIV-infected children asymptomatic for thrush proved to be colonized by Candida albicans, and disseminated colonization with Trichosporon beigelii occurred in one HIV-infected child. All cultures for dermatophytes were negative. While the carriage rate with fungi other than C. albicans was not increased in the HIV-infected group, the isolates recovered are known pathogens in the immunocompromised host and the colonization of these organisms may be a potential source of infection.

AIDS-Related Opportunistic Infections↗
PubMed1994

Sexually transmitted diseases, sexual behavior, and cocaine use in inner-city women.

The prevalence of untreated sexually transmitted diseases (STDs) was assessed in a cohort of 372 sexually active inner-city women (92% black, 49% US-born) with no history of injection drug use who were recruited in Brooklyn, New York, in 1990 and 1991. The presence of STDs was assessed via culture, serologic analyses, and medical history. Sexual and drug-use histories were obtained, as was a urine sample for toxicologic analysis. Thirty-five percent of the women had at least one STD (27% Trichomonas vaginalis, 6.8% Chlamydia trachomatis, 5.2% syphilis, 2.4% human immunodeficiency virus (HIV), and 1.4% Neisseria gonorrhoeae). US-born women were more likely than foreign-born (96% Caribbean) women to have an STD (50% vs. 22%; p < 0.001). Among US-born women, 61% of crack and/or cocaine users had an STD as opposed to 34% of non-users (OR = 2.9, 95% CI 1.6-5.5). Recent crack cocaine use was the strongest predictor of syphilis infection (OR = 12.8, p = 0.019), and was reported by each of the seven HIV-positive women. This study, based on a large sample with laboratory confirmation of both STDs and drug use, documents that women who use crack cocaine are at substantially higher risk of contracting an STD than other women. STD/HIV prevention programs in inner cities should target US-born women, particularly crack cocaine users.

Adult↗
PubMed1993

Exogenous reinfection with multidrug-resistant Mycobacterium tuberculosis in patients with advanced HIV infection.

BACKGROUND: In the United States there have been recent outbreaks of multidrug-resistant tuberculosis. These outbreaks have primarily involved persons infected with the human immunodeficiency virus (HIV). METHODS: We collected clinical information on 17 patients seen at a New York City hospital who had repeatedly positive cultures for Mycobacterium tuberculosis. Analysis of restriction-fragment--length polymorphisms (RFLPs) was performed on serial isolates of M. tuberculosis obtained from these patients. RESULTS: Six patients had isolates that remained drug-susceptible, and the RFLP patterns of these isolates did not change over time. Eleven patients had isolates that became resistant to antimicrobial agents. The RFLP patterns of the isolates from six of these patients remained essentially unchanged (two strains showed one additional band) despite the development of drug resistance. In five other patients, however, the RFLP patterns of the isolates changed dramatically at the time that drug resistance was detected. The change in the RFLP pattern of the isolate from one patient appeared to be the result of contamination during processing in the laboratory. In the remaining four patients, all of whom had advanced HIV disease, the clinical and microbiologic evidence was consistent with the presence of active tuberculosis caused by a new strain of M. tuberculosis. CONCLUSIONS: Resistance to antituberculous drugs can develop not only in the strain that caused the initial disease, but also as a result of reinfection with a new strain of M. tuberculosis that is drug-resistant. Exogenous reinfection with multidrug-resistant M. tuberculosis can occur either during therapy for the original infection or after therapy has been completed.

AIDS-Related Opportunistic Infections↗
PubMed1993

Comparison of the Syva MicroTrak enzyme immunoassay and Gen-Probe PACE 2 with cell culture for diagnosis of cervical Chlamydia trachomatis infection in a high-prevalence female population.

Culture is currently considered the "gold standard" for detecting Chlamydia trachomatis infections. We evaluated the Syva MicroTrak enzyme immunoassay (EIA) and Gen-Probe PACE 2 tests, which detect chlamydial antigens and rRNA, respectively. These assays were compared with each other and with culture for the detection of C. trachomatis in cervical specimens obtained from 217 women attending a clinic for sexually transmitted diseases. The prevalence of infection was 22.1% by culture. The sensitivity, specificity, and positive and negative predictive values were 79.2, 98.2, 92.6, and 94.3%, respectively, for EIA. For PACE 2, the respective values were 77.1, 97.6, 90.1, and 93.7%. After corrections for two false-negative cultures, the sensitivities and specificities were 80 and 99.4%, respectively, for the EIA and 78 and 98.8%, respectively, for the probe assay. Quantitative evaluation of the results showed that false-negative results with either assay were associated with cultures that had low inclusion counts or were negative without subpassage. Analysis of nonculture results revealed that 2.3% of the EIA results and 4.6% of the probe assay results were within +/- 30% of the respective assay cutoff values. These included four false-negative (one EIA and three probe) and two false-positive (one EIA and one probe) results. The Syva MicroTrak EIA and the Gen-Probe PACE 2 assay are comparable to but significantly less sensitive than culture. Use of a grey zone may help identify the need for repeat or confirmatory testing.

Adolescent↗
PubMed1992

Differential recovery of cytomegalovirus from cellular and supernatant components of bronchoalveolar lavage specimens.

The recovery of cytomegalovirus from bronchoalveolar lavage (BAL) specimens was compared after inoculation of MRC-5 tube and shell vial cell cultures with four different BAL preparations. Analysis of culture results obtained with 55 cytomegalovirus culture-positive samples showed significant differences in the ability to isolate virus from the supernatant and cellular components of these specimens. There was a 52% reduction in cytomegalovirus recovery and a significant delay in the development of cytopathic effect in cultures inoculated with the cellular component of BAL specimens when compared to cultures inoculated with crude BAL cells and fluid. The mean time for detection of cytopathic effect was 11.8 days in tubes inoculated with crude BAL and 18.2 days for tubes inoculated with BAL cells. A similar effect was observed using a rapid shell vial culture technique. A 39% reduction in the number of isolates and a 57% reduction in the number of positive cells were observed in vials inoculated with cells when compared to cultures inoculated with crude BAL. By contrast, using cell-free BAL supernatant as inoculum did not reduce the number of positive cultures or delay development of cytopathic effect. The results suggest that in most BAL specimens, cytomegalovirus is associated with the cell-free, rather than the cellular, component. Although BAL cell concentrates frequently are used for cultivation of viruses from BAL, our results showed that the use of these preparations results in a significant number of false-negative cytomegalovirus cultures.

Adult↗
PubMed1992

Mycobacterium xenopi, Mycobacterium fortuitum, Mycobacterium kansasii, and other nontuberculous mycobacteria in an area of endemicity for AIDS.

Between 1981 and 1990, cultures of specimens from 86 patients at State University of New York-Health Sciences Center at Brooklyn were positive for nontuberculous mycobacteria other than Mycobacterium avium/Mycobacterium intracellulare complex or Mycobacterium gordonae. The most common species isolated were Mycobacterium xenopi (33), Mycobacterium fortuitum (28), Mycobacterium kansasii (7), and Mycobacterium chelonae (6). Thirty-five patients (41%) had clinical and/or serological evidence of human immunodeficiency virus (HIV) infection. Patients from whom M. xenopi and M. kansasii were isolated were significantly more likely to be infected with HIV than were the remaining patients in this series. Most of the mycobacterial isolates were cultured from respiratory secretions. However, extrapulmonary infections with M. fortuitum, M. xenopi, M. kansasii, Mycobacterium terrae, and Mycobacterium scrofulaceum did occur among the HIV-infected patients.

Adolescent↗
PubMed1985

The relationship between intravenous fluid contamination and the frequency of tubing replacement.

Medical patients receiving IV therapy were randomly assigned to one of two IV tubing change groups. One group had a 48-hour tubing change and the other had no tubing change for the remainder of the cannula placement. A daily IV fluid specimen was processed microbiologically. To complete the study, a minimum of 3 continuous days of therapy and three fluid specimens was required. There were two contaminated specimens, one in each tubing change group. The contamination rate in the 48-hour change group was 0.87% and 0.96% in the no change group. The rate difference of 0.09% has a 95% confidence interval (-0.035 to +0.036) which includes zero. Survival analysis also revealed no significant difference in the cumulative probability of survival, however the mean duration of continuous tubing use of 4.3 days in the no change group and 1.8 days in the 48 hour change group were significantly different (p less than 0.05). The cumulative probability of surviving contamination free was 0.988 in the 48-hour group and 0.987 in the no-change group. We conclude that it is safe to change IV tubing at intervals up to but not exceeding 4 days.

Catheterization↗
PubMed1985

Comparison of ortho respiratory syncytial virus enzyme-linked immunosorbent assay and HEp-2 cell culture.

Two hundred seventy nasopharyngeal aspirates were tested in duplicate with the Ortho Diagnostics, Inc. (Raritan, N.J.), respiratory syncytial virus antigen enzyme-linked immunosorbent assay. The test was sensitive (80 to 82%) and specific (96%) when compared with cell culture. The enzyme-linked immunosorbent assay detected seven antigen-positive specimens not among the 71 specimens that were positive for respiratory syncytial virus in cell culture. A blocking test confirmed those specimens as true positives (specificity, 100%).

Antigens, Viral↗
PubMed1985

Cefoperazone therapy of complicated urinary tract infections: pharmacokinetics in renal transplant recipients.

Cefoperazone was used to treat patients with complicated urinary tract infections due to multiple antibiotic-resistant gram-negative rods who had failed prior courses of intravenous antibiotic therapy. Cure was achieved in 44% (4/9) of cases; 44% of patients improved but relapsed and 11% (1/9) of patients were reinfected. Relapse and reinfection were associated with Pseudomonas aeruginosa and/or with conditions not normally responsive to medical therapy alone including prostatitis, reflux and chronic indwelling Foley catheters. The pharmacokinetics of cefoperazone were studied in renal transplant recipients. Peak serum concentrations (range 146-241 micrograms/ml) and 2-hour noncumulative urine concentrations (range 161-291 micrograms/ml) exceeded the minimal inhibitory concentrations of the bacteria in all cases. There was no accumulation of cefoperazone despite the presence of impaired renal function.

Adult↗