Frank E. Kocka

Disseminated Infection with Mycobacterium kansasii in the Acquired Immunodeficiency Syndrome

Excerpt DisseminatedMycobacterium aviumcomplex is common in patients with the acquired immunodeficiency syndrome (AIDS). Infection withMycobacterium kansasiihas been reported rarely in patients wit...

Epidemiology and outcome of Clostridium difficile infection and diarrhea in HIV infected inpatients.

Clostridium difficile causes diarrhea in HIV infected patients but reports of prevalence, risk factors, and outcome vary. We studied the impact of C. difficile in 161 HIV infected inpatients admitted to Cook County Hospital. Patients with C. difficile had more hospital admissions in the previous 6 months (p =.04), spent more days in the hospital in the previous 3 months (p =.02), more often had previously received H2 blockers or treatment for Pneumocystis carinii (p <.05), and had a more frequent history of herpesvirus (p =.03) or opportunistic infections (p =.04). C. difficile associated diarrhea (CDAD) was the etiology in 32% of all study patients with diarrhea. Patients with CDAD were hospitalized for longer periods (p =.02) and received more antibiotics (p =.002). C. difficile was frequently present in our HIV infected patients, especially those with advanced HIV disease, but appeared to have little impact on morbidity or mortality.

Possible overestimation of penicillin resistant Streptococcus pneumoniae colonization rates due to misidentification of oropharyngeal streptococci

Standard identification of Streptococcus pneumoniae by optochin and bile solubility testing can lead to ambiguous results for certain isolates. Newer bacteriologic identification techniques (e.g., DNA probes) now exist. In a prospective point prevalence study of oropharyngeal S. pneumoniae carriage rates among outpatients, we compared standard organism identification techniques to DNA probe testing. By standard identification criteria, 35 (4%) of 872 isolates were characterized as presumptive S. pneumoniae. Thirty of 35 presumptive isolates were recoverable for DNA probing; 9 (30%) presumptive isolates were confirmed using a DNA probe. The antimicrobial susceptibility pattern of these DNA probe positive isolates closely paralleled that of clinical blood isolates of S. pneumoniae obtained during the study period. The 21 (70%) DNA probe negative isolates, which may represent phylogenetically related species (such as S. mitis or S. oralis), had significantly reduced antimicrobial susceptibility patterns when compared with the DNA probe positive isolates. In colonization studies, if classic criteria (optochin disc zone and bile solubility) are the sole means of identification, S. pneumoniae penicillin resistance rates may be over-reported.

Use of DNA Fingerprinting To Assess Tuberculosis Infection Control

The resurgence of tuberculosis in the United States in the 1980s and early 1990s was accompanied and exacerbated by an increase in the nosocomial spread of tuberculosis [1, 2]. Several tragic and well-publicized nosocomial outbreaks of multi-drug-resistant tuberculosis led to the reevaluation of tuberculosis infection-control practices and to revision of the Centers for Disease Control and Prevention (CDC) guidelines on tuberculosis infection control [3-6]. The revised CDC guidelines propose a hierarchy of control measures, emphasizing administrative controls over engineering controls and personal respiratory devices. Since the guidelines have been available, many hospitals have implemented the recommended practices, and early studies and surveillance data have demonstrated the efficacy of these practices [7-10]. Recently, the Occupational Safety and Health Administration (OSHA) proposed new requirements for tuberculosis infection control that exceed the CDC guidelines with respect to burden on infection-control resources [11]. Critics of the OSHA proposal believe that the evidence that health care workers are at continued substantial risk for occupational tuberculosis is not sufficient to justify the increased expenditure [12]. Because it illustrates genetic relatedness among strains of M. tuberculosis, DNA fingerprinting has been used by epidemiologists and clinicians to confirm suspected outbreaks of disease and episodes of laboratory cross-contamination [3, 13, 14]. We hypothesized that routine DNA fingerprinting, done by using restriction fragment length polymorphism analysis, could be used to enhance hospital infection-control surveillance for patient-to-patient transmission of Mycobacterium tuberculosis. To test this hypothesis, we performed DNA fingerprinting on all M. tuberculosis isolates obtained from Cook County Hospital, Chicago, Illinois, over a 1-year period. During this period, no patient-to-patient transmission had been detected by routine hospital infection-control practices. Methods Setting Cook County Hospital is a 700-bed public hospital that serves a primarily indigent urban population. The prevalences of tuberculosis and HIV infection are high; the latter accounts for 9% of inpatient days. Administrative controls, including aggressive triage of patients with possible tuberculosis in the emergency department, have led to the widespread use of respiratory isolation for patients with known or suspected pulmonary tuberculosis. Patients with pulmonary tuberculosis are kept in respiratory isolation until they have clinical improvement while receiving therapy and have negative results on acid-fast smears on 3 separate days. Engineering controls consist primarily of isolation rooms that have been retrofitted with window exhaust fans to comply with recommended air-handling guidelines [6]. Health care workers wear personal respirators, approved by the National Institute for Occupational Health and Safety, while in respiratory isolation rooms; isolated patients wear surgical masks when not in negative-pressure rooms. Despite these measures, a few patients who are not isolated promptly on admission receive a diagnosis of pulmonary tuberculosis each year. In addition, the hospital has outpatient areas (including an HIV clinic) in which patients spend many hours in close proximity and where unrecognized tuberculosis can spread. Laboratory Studies During the 12-month study period (1 April 1995 to 31 March 1996), one M. tuberculosis isolate from every patient with tuberculosis at Cook County Hospital was sent to the Michigan Department of Community Health for DNA fingerprinting. All isolates were analyzed by standard methods [15] by using a 246-base pair probe representing the IS6110 sequences to the right of the PvuII site. The probe was labeled with horseradish peroxidase for detection by enhanced chemiluminescence (ECL Direct Labeling and Detection System, Amersham, Arlington Heights, Illinois) and was hybridized to DNA from M. tuberculosis isolates restricted with PvuII. PvuII-restricted DNA from M. tuberculosis strain MT14323, containing 14 copies of IS6110, was used as a DNA size marker. Autoradiographs were produced by exposing the hybridized blots to Hyperfilm ECL (Amersham). Secondary fingerprinting done by using a probe for the polymorphic guanine cytosine-rich repetitive sequence (PGRS) has proven useful for confirming the genetic relatedness of M. tuberculosis isolates [16-20]. This second assay was performed, with the recombinant plasmid pTBN12 and the methods described above, on isolates with identical IS6110 fingerprints of 5 or fewer hybridizing bands and isolates with more than 5 hybridizing bands with fragment patterns that differed by 1 to 2 bands. A 1-kilobase ladder was included as a size marker (Gibco, Gaithersburg, Maryland). The pTBN12 was donated by Don Cave (John L. McClellan Memorial Veterans Hospital, Little Rock, Arkansas). We compared IS6110 and PGRS fingerprints by using Whole Band Analyzer software, version 3.2.2 (BioImage, Inc., Ann Arbor, Michigan). The average linkage clustering method was used to match patterns with an SD of 2.5%. Matching patterns were compared visually to ensure similarity. For PGRS fingerprinting, only hybridizing bands greater than 1.6 kilobases were analyzed. Isolates were considered to be genetically related (that is, clustered) if they had identical IS6110 patterns of more than 5 bands, had IS6110 patterns of more than 5 bands that differed by 1 to 2 bands and had identical PGRS patterns, or had IS6110 patterns of 5 or fewer bands and had identical PGRS patterns. Susceptibility testing was done at the Cook County Hospital laboratory. Susceptibilities on any isolate found to be resistant to one or more first-line drugs (isoniazid, rifampin, ethambutol, or streptomycin) were confirmed by the Illinois Department of Public Health laboratory. Clinical Data Collection Demographic information and disease characteristics were gathered by review of the medical record for the first admission during which tuberculosis was diagnosed. This record was available for 166 of 173 patients whose isolates were fingerprinted (96%), and data were available from other sources [such as the outpatient record or the Department of Health tuberculosis database] for most of the other 7. Screening for laboratory cross-contamination was done for all clustered isolates. Laboratory cross-contamination was considered likely when 1) only one culture was positive for tuberculosis, 2) the specimen was negative on an acid-fast smear, 3) the clinical syndrome was not consistent with tuberculosis, and 4) the specimen was processed on the same day as the specimen of a patient whose isolate had a matching DNA fingerprint [13, 14]. To determine whether nosocomial transmission of M. tuberculosis had occurred between patients with clustered isolates, the times and locations of all outpatient visits and inpatient admissions from 1 April 1993 to 31 March 1996 were reviewed. If two or more patients who had isolates in a cluster had been in any inpatient or outpatient area of the hospital on the same day before they had both received a diagnosis of tuberculosis, the medical records were reviewed to determine the likelihood of M. tuberculosis transmission. Data were gathered on hospital or clinic location, use of and compliance with respiratory isolation, acid-fast smear status, HIV infection status, tuberculin skin-test status, and susceptibility patterns. Records were also reviewed to determine whether the patients had concurrently undergone laboratory or radiographic procedures or had obtained medication at the same pharmacy. Data on hospital location, time of registration, and time and location of laboratory and radiographic procedures were obtained from a computerized database that is complete and accurate; data on drug susceptibility were available for all patients with clustered isolates who were on hospital grounds concurrently with another patient with clustered isolates. If patients were registered in the emergency department on sequential days, the records were reviewed to determine whether temporal overlap existed. Contact Tracing The results of hospital contact tracing were reviewed. Tracing is done when a patient who has not been appropriately isolated receives a diagnosis of acid-fast smear-positive pulmonary tuberculosis. Employees who may have been exposed to this patient are identified by their supervisors and undergo tuberculin skin testing with chest radiography, if appropriate. All employees receive routine tuberculin skin testing annually. Compliance with this testing is a condition of continued employment. The results of community contact tracing performed by the Chicago Department of Public Health were reviewed to identify out-of-hospital links between patients whose isolates were clustered. Contact tracing is done for all cases of pulmonary tuberculosis and consists of interview with the patient to identify close contacts. Contacts undergo tuberculin skin testing and, if conversions are detected, the circle of contact tracing is widened by repeated interviews to include more casual contacts, who are also tested. Community contact tracing beyond that performed by the Chicago Department of Public Health was not done in our study. Statistical Analysis Chi-square tests (or the Fisher exact test, when expected cell sizes were <5) were used to test the association of clustering with patient demographic and clinical characteristics. Two-tailed P values are presented with relative risks (RRs) and 95% CIs. All variables found to be significantly associated with clustering on univariate analysis were entered into a logistic model by using the statistical software package SPS, version 8.0 (SPS, Inc., Chicago, Illinois). The output of the model, which was the ln(odds) of clustering, was converted to the probability of clustering. Results Mycobacterium tuberculosis was recovered f

Manifestations of Kingella kingae infections in adults: Resemblance to neisserial infections

Kingella kingae is a rare human pathogen. Most reported infections are in children and involve endocardium, vascular space, and skeletal tissues. We report herein two cases of K. kingae infection recently seen in adults. Kingella kingae caused acute meningitis in a patient with sickle cell anemia and in the second patient with alcoholic liver disease, sepsis with a petechial rash. The clinical presentation due to K. kingae closely resembled that caused by related Neisseria genus.

Difference in the incidence of Clostridium difficile among patients infected with human immunodeficiency virus admitted to a public hospital and a private hospital

OBJECTIVE To compare the occurrence of Clostridium difficile among inpatients infected with human immunodeficiency virus (HIV) in two different hospitals. DESIGN Prospective, observational study. SETTING Specialized HIV inpatient units. PATIENTS HIV-infected inpatients at Cook County Hospital (CCH) and Rush Presbyterian St. Lukes Medical Center (RPSLMC). INTERVENTIONS A clinical and epidemiologic assessment of patient risk factors for C. difficile was performed. C. difficile isolates found on stool, rectal, and environmental cultures were typed by pulsed-field gel electrophoresis. RESULTS Twenty-seven percent of patients admitted to CCH versus 4% of patients admitted to RPSLMC had positive cultures for C. difficile (P = .001). At CCH, 14.7% of environmental cultures were positive versus 2.9% at RPSLMC (P = .002). Risk factors for C. difficile acquisition included hospitalization at CCH, more severe HIV, use of acyclovir and H2-blockers, and longer hospital stay. Patients admitted to CCH were taking more antibiotics, had longer hospital stays, and more frequently had a history of C. difficile infection. During the study, two strains (CD1A and CD4) extensively contaminated the CCH environment. However, only CD1A caused an outbreak. CONCLUSIONS The C. difficile acquisition rate at CCH was sevenfold higher than that at RPSLMC, and CCH had a more contaminated environment. Differences in patient acquisition rates likely reflect a greater prevalence of traditional C. difficile risk factors and a concurrent outbreak at CCH. Although two strains heavily contaminated the environment at CCH, only one caused an outbreak, suggesting that factors other than the environment are important in initiating C. difficile outbreaks.

Predominance of a single restriction endonuclease analysis group with intrahospital subgroup diversity among Clostridium difficile isolates at two Chicago hospitals.

OBJECTIVE To determine the epidemiology and relatedness of Clostridium difficile isolates in two geographically separated hospitals in a large metropolitan area, each with unique patients and personneL DESIGN: Observational descriptive molecular epidemiology of clinical C. difficile isolates. SETTING Two tertiary-care hospitals in Chicago. METHODS Consecutive C. difficile isolates from the clinical laboratory of a Veterans Affairs hospital during a 13-month period were typed by restriction endonuclease analysis (REA). During an overlapping 3-month period, stool specimens that tested positive for C. difficile toxin from patients at a nearby county hospital were cultured and the recovered isolates typed by the same method. RESULTS Nineteen (68%) of 28 nosocomial isolates at the smaller, Veterans Affairs hospital belonged to REA group K. Within this group of closely related strains, 9 distinct REA types were recognized. Twenty-one (72%) of 29 nosocomial isolates at the larger, county hospital also belonged to group K. However, the predominant REA types within group K differed markedly at each institution. CONCLUSIONS These findings demonstrate a high degree of similarity among nosocomial C. difficile strains from different hospitals in the same city and suggest the possibility of an extended outbreak of a prototype group K strain with subsequent genetic drift at the two different institutions.

Clinical Evaluations of the Wellcolex Colour Shigella and Salmonella Tests

The Wellcolex Colour Salmonella and Shigella tests are rapid latex agglutination procedures for grouping Salmonella and Shigella using an antibody attached to multicolored latex particles. The tests correctly grouped 46 (100%) of 46 Salmonella clinical isolates in groups A through E and G, 42 (100%) of 42 Shigella clinical isolates, and seven (88%) of eight Shigella stock cultures. The stock culture missed had been passed through many transfers and may have lost some of its antigenicity. The Wellcolex Colour Salmonella test was also found useful in detecting and grouping Salmonella spp. directly from blood culture bottles.

Isospora belli and Cryptosporidium sp. from a patient not suspected of having acquired immunodeficiency syndrome

Several protozoa including Cryptosporidium sp. and Isospora belli were found in a stool specimen from a patient not suspected of having Acquired Immunodeficiency Syndrome (AIDS). As a result of the parasitologic findings, serologic tests were ordered that verified the diagnosis of AIDS. All stool specimens are routinely tested for presence of acid fast organisms with a modified acid fast technique.

Detection of brucella sp from blood and bone marrow

Brucella sp were detected in the blood of four patients with the use of the infrared nonradiometric BACTEC 660. The clinical presentations of the patients were considerably different in that brucellosis was not the initial diagnosis.