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Routine use of PCR-restriction fragment length polymorphism analysis for identification of mycobacteria growing in liquid media.

A PCR-restriction fragment length polymorphism (PCR-RFLP) procedure capable of rapidly identifying 28 species of clinically encountered mycobacteria was evaluated for use in the routine identification of acid-fast isolates growing in BACTEC 12B and 13A liquid media. PCR-RFLP identified 100 of 103 acid-fast isolates recovered from 610 patient specimens submitted for culture during the study. The three isolates unidentifiable by PCR-RFLP produced restriction patterns not included in the PCR-RFLP algorithm and could therefore not be assigned to a species. These isolates were characterized by their morphologic and biochemical characteristics. Two of the isolates were identified as M. terrae complex and M. gordonae. The third isolate could not be definitively identified and could only be characterized as a Mycobacterium sp. most closely resembling M. chelonae. PCR-RFLP identifications agreed with the conventional identifications for 96 of the 100 isolates identified by PCR-RFLP. Subsequent identification of the four discordant isolates by gas chromatography analysis supported the PCR-RFLP identification of each isolate. Amplification products were also obtained from isolates of Streptococcus albus and Rhodococcus equi recovered from patient specimens; however, the restriction patterns of these nonmycobacterial species did not resemble the patterns of any mycobacterial species included in the PCR-RFLP algorithm. PCR-RFLP seems to be a reliable procedure for the routine identification of mycobacteria and has the potential for providing identifications of mycobacterial isolates which are more accurate than conventional identification techniques based on morphologic and biochemical characteristics.

Bacterial Typing Techniques↗

Fatal pulmonary infection associated with a novel organism, "para-streptomyces abscessus".

Actinomycetes are increasingly recognized as pathogenic in the immunocompromised host. We isolated an asporogenous, nonmotile, aerobic gram-positive rod from a transplant recipient with a fatal pulmonary infection. The pathology was similar to that associated with Rhodococcus equi, including intra-histiocytic localization. The organism was relatively inert in standard biochemical tests. 16S rRNA gene sequencing indicated a potentially unique organism most closely related to the genus Streptomyces, for which we propose the name "Para-streptomyces abscessus."

Actinomycetales Infections↗

Interpretation of chest radiographs in AIDS patients: usefulness of CD4 lymphocyte counts.

Specific infections and neoplasms that are complications of acquired immunodeficiency syndrome (AIDS) occur within various CD4 lymphocyte count ranges. Knowledge of how these counts correlate with radiographic appearances of these entities can limit the differential diagnosis because certain conditions are uncommon above a specific count. In patients with CD4 lymphocyte counts above 200 cells/mm3 and radiographic findings of cavitary and noncavitary consolidation, bacterial pneumonia and Mycobacterium tuberculosis are the major diagnostic considerations. As the CD4 lymphocyte count falls, these infections are still common; however, cavitation is seen less frequently with Mycobacterium tuberculosis, and unusual bacterial infections, including those caused by Rhodococcus equi and Nocardia asteroides, should be considered. In patients with counts below 200 cells/mm3, Pneumocystis carinii pneumonia is the most common infection, usually manifesting radiographically as a reticular interstitial pattern. At CD4 lymphocyte counts of 50-200 cells/mm3, disseminated fungal infection and Kaposi sarcoma become prevalent. In patients with advanced AIDS and counts below 50 cells/mm3, radiographic nodular or reticular patterns may indicate AIDS-related lymphoma and cytomegalovirus and Mycobacterium avium-intracellulare infections. When CD4 lymphocyte counts are applied to interpretation of chest radiographs in AIDS patients, the working differential diagnosis of a radiographic pattern can be tailored to the clinical situation of a given patient.

AIDS-Related Opportunistic Infections↗

In vitro antimicrobial activity of gatifloxacin compared with other quinolones against clinical isolates from cancer patients.

Owing to the predominance of gram-positive pathogens in neutropenic cancer patients, newer generation quinolones with an expanded gram-positive spectrum and enhanced potency, may have a role to play for prophylaxis and/or empiric therapy in such patients. The in vitro activity of gatifloxacin was compared with that of ciprofloxacin, levofloxacin and trovafloxacin against 848 recent clinical isolates from cancer patients. Against gram-positive organisms, gatifloxacin was the most active agent tested inhibiting all Aerococcus, Listeria monocytogens, Micrococcus, Stomatococcus mucilaginous, Bacillus, and Rhodococcus equi strains at < or =2 mg/l, its designated susceptibility breakpoint. It was also very active against methicillin-susceptible staphylococci and Streptococcus spp. (including penicillin nonsusceptible Streptococcus pneumoniae and viridans streptococci). It had moderate activity against methicillin-resistant staphylococci and Enterococcus faecalis, inhibiting 68-80% of these strains at < or =2 mg/l. Gatifloxacin also had good activity against the Enterobacteriaceae (although ciprofloxacin was more potent) inhibiting >95% of isolates at < or =1 mg/l. Nonfermentative gram-negative organisms were less susceptible to all 4 agents. Gatifloxacin was very active against Acinetobacter lwoffi (MIC100 0.12 mg/l) and had moderate activity against Acinetobacter baumanii, Chryseobacterium spp., Stenotrophomonas maltophilia, Pseudomonas aeruginosa and other Pseudomonas species. Alcaligenes xylosoxidans strains were relatively resistant to all 4 agents.

Anti-Bacterial Agents↗

Pulmonary malakoplakia coexistent with tuberculosis of the hilar lymph node mimicking malignancy.

Pulmonary malakoplakia is a disease that is difficult to diagnose because its symptoms vary from those mimicking bronchogenic carcinoma to pneumonitis-like tuberculous infections. Malakoplakia is an unusual inflammatory condition characterized by the accumulation of macrophages with diagnostic Michaelis-Gutmann bodies. In this study, an immunocompromised patient with a tumor mass in the upper lobe of the right lung coexisting with hilar node enlargement is presented. A thoracoscopic biopsy revealed pulmonary malakoplakia with tuberculosis of the hilar lymph node. Microbiologic cultures were positive for acid-fast positive bacilli from the hilar node specimen, and negative for any other microorganisms such as Rhodococcus equi, but positive for Escherichia coli from the lung specimen. The significance of these findings and the coincidental association between malakoplakia and tuberculosis are discussed.

Aged↗

Pulmonary malakoplakia diagnosed by fine needle aspiration. A case report.

BACKGROUND: Pulmonary malakoplakia is an uncommon disorder, with 24 previously reported cases, only 4 of which were diagnosed by bronchial washings, bronchial brushings or aspiration cytology. We report a case that was diagnosed initially by computed tomography (CT)-guided fine needle aspiration (FNA) cytology. CASE: A 56-year-old male with follicular small cleaved cell lymphoma had a 10-cm left lower lobe mass compressing the main bronchus to that lobe. A transthoracic, CT-guided FNA specimen consisted predominantly of foamy macrophages, many of which contained typical Michaelis-Gutmann bodies. Microbiologic cultures identified Rhodococcus equi. A subsequent transbronchial biopsy and left pneumonectomy specimen confirmed the cytologic diagnosis. CONCLUSION: Pulmonary malakoplakia associated with R equi pneumonia is a rare lesion that is essentially limited to immunocompromised hosts. Awareness of the FNA cytomorphology of this lesion permits resolution of the typical clinical differential diagnosis of pulmonary masses in the immunocompromised host and can facilitate treatment.

AIDS-Related Opportunistic Infections↗

Cardiac tamponade in patients with human immunodeficiency virus disease.

The characteristics of cardiac tamponade in patients with human immunodeficiency virus (HIV) disease were examined by evaluating the cases, case series, and related articles, including autopsy series, identified through a comprehensive literature search. One-hundred eighty-five cases of cardiac tamponade have been reported in patients with HIV disease. Sex data were available in 176 patients, of whom 154 (87%) were males. The mean age was 34.7 +/- 10.4 years (range, 11 months to 61 years). Mean CD4 cell count was 98 +/- 95 cells/mm3 (range, 3 to 430 cells/mm3). The most common etiology of pericardial tamponade was mycobacterial infection (78 patients), including Mycobacterium tuberculosis, Mycobacterium avium-intracellulare, and Mycobacterium kansasii. A bacterial cause was found in 20 patients (11%). Staphylococcus aureus was the predominant bacteria, followed by streptococci, Pseudomonas aeruginosa, Listeria monocytogenes, Klebsiella pneumoniae, and Rhodococcus equi. Lymphoma was found in 15 (8%) patients and Kaposi sarcoma in 13 (7%) patients. Numerous unusual organisms, including Cryptococcus neoformans, Nocardia asteroides, Aspergillus species, cytomegalovirus, and herpes simplex were also associated with cardiac tamponade in HIV patients. Occasionally, HIV itself was involved in the pathogenesis. In 48 patients (26%), no cause was found or reported. The most common clinical presentation was dyspnea, followed by fever, cough, chest pain, and cardiac arrest. The predominant pericardial fluid color composition was serosanguineous. The majority of patients died during hospitalization or in the immediate follow-up period. Vigilance for cardiac tamponade in patients with HIV disease, especially in those with opportunistic infections and/or malignancies, and cardiac symptoms, may result in early and proper management of cardiac tamponade in these patients.

AIDS-Related Opportunistic Infections↗

Malakoplakia of the prostate on needle core biopsy: a case report and review of the literature.

Malakoplakia is a rare inflammatory disorder that results from an infectious process and that may be associated with immunosuppression. It most often occurs in the genitourinary tract; however, isolated cases have been reported in many other organs, including colon, stomach, lung, liver, bone, uterus, and skin. In the bladder, which is the most common site of involvement, it may be mistaken for malignancy on cystoscopic examination or computerized topography scan. Gram-negative bacteria such as Escherichia coli and Klebsiella pneumonia are often isolated from malakoplakia lesions, although other less common bacteria such as Rhodococcus equi may also be found. This is a case report of prostatic malakoplakia diagnosed on needle core biopsy from a patient suspected to harbor a malignancy.

Aged↗

Assignment of the bacterial agent of urinary calculus in young rats by the comparative sequence analysis of the 16S rRNA genes of corynebacteria.

Comparative 16S rRNA gene sequencing was used to assign four isolates of spontaneous urinary calculus in young laboratory rats. The phylogenetic relationships among the rat isolates and selected species of corynebacteria were also inferred. Based on the homology and evolutionary distance analysis, the 16S rRNA genes of the rat isolates were almost identical with that of Corynebacterium renale ATCC 19412. Also the results of the phylogenetic analysis showed a close relationship among the isolates and C. renale, but they were clearly different from C. pilosum, C. cystitidis, C. kutscheri and Rhodococcus equi. The results of the present study and previously published biochemical data demonstrate that the organism involving urinary infections in young rats is identified to be C. renale.

Animals↗

Transthoracic needle aspiration in the study of pulmonary infections in patients with HIV.

STUDY OBJECTIVE: To evaluate the safety and efficacy of transthoracic aspiration with an ultrathin needle in the microbiologic diagnosis of pulmonary infections in HIV-infected patients. DESIGN: Retrospective review of cases. SETTING: A 500-bed teaching hospital in Lleida, Spain. PATIENTS: Forty-five HIV-infected patients admitted between March 1989 and March 1993 with clinical and roentgenographic evidence of pulmonary infection and without contraindications for transthoracic needle aspiration (TNA). INTERVENTIONS: Forty-seven TNAs were performed in the emergency room (20) or during hospitalization (27). The TNA procedures were done without premedication and without fluoroscopic guidance. Specimens were processed using routine microbiologic and cytologic techniques; in addition, polymerase chain reaction (PCR) for Pneumocystis carinii was carried out since March 1992. Development of adverse effects was carefully evaluated. RESULTS: The TNA was effective in 29 (62 percent) out of 47 procedures. The diagnosis was obtained for 14 of 15 patients with P carinii pneumonia, 8 out of 14 patients with bacterial pneumonia, and 4 out of 12 patients with tuberculosis. Other pathogens recovered were Nocardia asteroides, Cryptococcus neoformans, Rhodococcus equi, and Mycobacterium avium. No false-positive results were obtained. Pneumothorax developed in eight (17 percent) procedures, but only one procedure resulted in a pleural drainage; the incidence of other adverse effects was low and clinically irrelevant. CONCLUSION: Our study suggests that TNA can be a useful technique in establishing the etiologic diagnosis of pulmonary infections in HIV-infected patients, with a good sensitivity, high specificity, and relatively low incidence of serious complications, with TNA appearing as a reliable alternative to more uncomfortable methods.

AIDS-Related Opportunistic Infections↗

[Bacterial infections in patients infected by HIV].

Individuals infected by the human immuno deficiency are more prone to suffering certain bacterial infections in the course of their clinical evolution. The agents involved in these infections are: Streptococcus pneumoniae, Haemophilus influenzae, Pseudomonas aeruginosa, Salmonella spp and Campylobacter spp, which occasion an increase in morbidity and mortality. With a lower frequency, but with an equal morbidity and mortality, infections have been found caused by Rhodococcus equi, Nocardia spp and Bartonella spp. Even though all of them account for a selective impairment of immunodeficiency in one way or another, their incidence varies. Other factors such as degree of immuno suppression, habits, social and geographic living environment could be important. In general, there is a lack of chemoprophylactic strategies for their prevention. Early diagnosis and correct treatment could have important advantages for the quality of life and survival of these patients

English Abstract↗

Effects of prior feeding on pharmacokinetics and estimated bioavailability after oral administration of a single dose of microencapsulated erythromycin base in healthy foals.

OBJECTIVE: To determine effects of prior feeding on pharmacokinetics and estimated bioavailability of orally administered microencapsulated erythromycin base (MEB) in healthy foals. ANIMALS: 6 healthy foals, 3 to 5 months old. PROCEDURE: Foals were given 2 doses of MEB (25 mg/kg of body weight, PO). One dose was administered after food was withheld overnight, and the other was administered after foals had consumed hay. The study used a crossover design with a 2-week period between doses. Blood was collected via a jugular vein prior to and at specific times after drug administration. Concentrations of erythromycin A and anhydroerythromycin A in plasma were determined, using high-performance liquid chromatography. Results pharmacokinetic analysis of plasma concentration-time data for food-withheld and fed conditions were compared. RESULTS: Plasma concentrations of erythromycin A for foals were lower after feeding than concentrations when food was withheld. Area under the plasma concentration-time curve, maximum plasma concentration, and estimated bioavailability were greater in foals when food was withheld than when foals were fed. Anhydroerythromycin A was detected in plasma after administration of MEB in all foals. CONCLUSIONS AND CLINICAL RELEVANCE: Foals should be given MEB before they are fed hay. Administration of MEB to foals from which food was withheld overnight apparently provides plasma concentrations of erythromycin A that exceed the minimum inhibitory concentration of Rhodococcus equi for approximately 5 hours. The dosage of 25 mg/kg every 8 hours, PO, appears appropriate.

Administration, Oral↗

Pharmacokinetics of erythromycin estolate and erythromycin phosphate after intragastric administration to healthy foals.

OBJECTIVE: To determine pharmacokinetics and plasma concentrations of erythromycin and related compounds after intragastric administration of erythromycin phosphate and erythromycin estolate to healthy foals. ANIMALS: 11 healthy 2- to 6-month-old foals. PROCEDURE: Food was withheld from foals overnight before intragastric administration of erythromycin estolate (25 mg/kg of body weight; n = 8) and erythromycin phosphate (25 mg/kg; 7). Four foals received both drugs with 2 weeks between treatments. Plasma erythromycin concentrations were determined at various times after drug administration by use of high-performance liquid chromatography. Maximum plasma peak concentrations, time to maximum concentrations, area under plasma concentration versus time curves, half-life of elimination, and mean residence times were determined from concentration versus time curves. RESULTS: Maximum peak concentration of erythromycin A after administration of erythromycin phosphate was significantly greater than after administration of erythromycin estolate (2.9 +/- 1.1 microg/ml vs 1.0 +/- 0.82 microg/ml). Time to maximum concentration was shorter after administration of erythromycin phosphate than after erythromycin estolate (0.71 +/- 0.29 hours vs 1.7 +/- 1.2 hours). Concentrations of anhydroerythromycin A were significantly less 1 and 3 hours after administration of erythromycin estolate than after administration of erythromycin phosphate. CONCLUSIONS AND CLINICAL RELEVANCE: Plasma concentrations of erythromycin A remained > 0.25 microg/ml (reported minimum inhibitory concentration for Rhodococcus equi) for at least 4 hours after intragastric administration of erythromycin phosphate or erythromycin estolate, suggesting that the recommended dosage for either formulation (25 mg/kg, q 6 h) should be adequate for treatment of R equi infections in foals.

Animals↗

Pharmacokinetics of azithromycin and concentration in body fluids and bronchoalveolar cells in foals.

OBJECTIVE: To determine the pharmacokinetics of azithromycin and its concentration in body fluids and bronchoalveolar lavage cells in foals. ANIMALS: 6 healthy 6- to 10-week-old foals. PROCEDURE: Azithromycin (10 mg/kg of body weight) was administered to each foal via i.v. and intragastric (i.g.) routes in a crossover design. After the first i.g. dose, 4 additional i.g. doses were administered at 24-hour intervals. A microbiologic assay was used to measure azithromycin concentrations in serum, peritoneal fluid, synovial fluid, pulmonary epithelial lining fluid (PELF), and bronchoalveolar (BAL) cells. RESULTS: Azithromycin elimination half-life was 20.3 hours, body clearance was 10.4 ml/min x kg, and apparent volume of distribution at steady state was 18.6 L/kg. After i.g. administration, time to peak serum concentration was 1.8 hours and bioavailability was 56%. After repeated i.g. administration, peak serum concentration was 0.63 +/- 0.10 microg/ml. Peritoneal and synovial fluid concentrations were similar to serum concentrations. Bronchoalveolar cell and PELF concentrations were 15- to 170-fold and 1- to 16-fold higher than concurrent serum concentrations, respectively. No adverse reactions were detected after repeated i.g. administration. CONCLUSIONS AND CLINICAL RELEVANCE: On the basis of pharmacokinetic values, minimum inhibitory concentrations of Rhodococcus equi isolates, and drug concentrations in PELF and bronchoalveolar cells, a single daily oral dose of 10 mg/kg may be appropriate for treatment of R. equi infections in foals. Persistence of high azithromycin concentrations in PELF and bronchoalveolar cells 48 hours after discontinuation of administration suggests that after 5 daily doses, oral administration at 48-hour intervals may be adequate.

Administration, Oral↗

Pathogenetic role of phagocytic abnormalities in human virus immunodeficiency infection: possible therapeutical approaches. A review.

Polymorphonuclear cells (PMN) and monocytes/macrophages (M/M) represent the first defence line against invading microorganisms. Both phagocytic cell functions are precociously compromised in human immunodeficiency virus (HIV)-infected subjects, thus leading to infectious and neurological complications in the late stages of disease. Among intracellular pathogens, emerging bacteria such as Bartonella henselae and Rhodococcus equi can cause peculiar clinical pictures, i.e. the bacillary parenchimal angiomatosis and a classical pyogranulomatous broncopneumonia, respectively. On the other hand, overproduction of proinflammatory cytokines (CKs) and, in particular, tumor necrosis factor-alpha under HIV or lipopolysaccharide stimulation may cause neural damage in terms of demyelination and subsequent development of acquired immunodeficiency syndrome (AIDS) dementia complex. Some therapeutical attempts have been made with colony stimulating factors in order to increase the number and potentiate the function of PMN and M/M. On the other hand, the use of drugs able to reduce exaggerated release of CKs by M/M is suggested in AIDS patients in order to prevent a further aggravation of the clinical condition.

HIV Infections↗

Comparison of microbiologic and high-performance liquid chromatography assays to determine plasma concentrations, pharmacokinetics, and bioavailability of erythromycin base in plasma of foals after intravenous or intragastric administration.

OBJECTIVE: To determine pharmacokinetics and bioavailability of erythromycin base after intragastric administration and erythromycin lactobionate after IV administration to healthy foals and to compare a microbiologic assay with a high-performance liquid chromatography (HPLC) method to determine plasma concentrations of erythromycin A. ANIMALS: 6 healthy foals that were 2 to 4 months old. PROCEDURE: Foals were given single doses of erythromycin (10 mg/kg of body weight, IV, and 25 mg/kg, intragastrically) in a crossover study. Venous blood samples were obtained at specific times after drug administration, and plasma was harvested for determination of erythromycin concentrations by microbiologic assay and a HPLC method Pharmacokinetic analysis of plasma concentration-time data was performed, and results derived from each method were compared. RESULTS: Concentration-time profiles for IV administration were best described by a two-compartment open model. Comparing pharmacokinetic data obtained by the 2 methods revealed substantial differences in results. Values for area under the plasma concentration-time curve and area under the first moment of the curve were substantially higher when determined by the bioassay, indicating overestimation of plasma concentration-time data by this method. The derived rate transfer constants (K21 and K(e)1) and mean residence time were significantly different, when determined by the bioassay. Systemic bioavailability of erythromycin base was low in all foals. CONCLUSIONS AND CLINICAL RELEVANCE: The bioassay method overestimated plasma concentrations of erythromycin, compared with the HPLC method. Despite low systemic bioavailability of erythromycin base administered intragastrically, plasma concentrations of erythromycin exceeded, for at least 4 hours, the minimum inhibitory concentration of most Rhodococcus equi isolates.

Animals↗

Pulmonary infection in human immunodeficiency virus-infected patients in Taiwan.

BACKGROUND: Pulmonary infection is a major cause of morbidity and mortality in human immunodeficiency virus (HIV)-infected patients. METHODS: We conducted a retrospective analysis of the pathogens causing pulmonary infection in 272 HIV-infected patients admitted to a university hospital from January 1993 through December 1998. RESULTS: A total of 158 (58%) patients had pulmonary complications, all but two of whom had acquired immunodeficiency syndrome (AIDS). There were 156 episodes of pulmonary infection, involving 124 patients. The most common pulmonary infection was Pneumocystis carinii pneumonia (PCP): 66 patients had 77 episodes of PCP, all of which occurred in patients with CD4+ lymphocyte counts below 0.2 x 10(9)/L (200/microL). Pulmonary tuberculosis (TB), diagnosed in 47 patients, was the second most common pulmonary infection. Twenty TB patients had open TB. HIV-infected patients who were immigrants from Southeast Asia (9/23, 39%) had a higher risk of developing pulmonary TB than nonimmigrants (38/249, 15%) (p = 0.004). Only one of 17 episodes of community-acquired bacterial pneumonia was caused by Streptococcus pneumoniae. Less common opportunistic pulmonary pathogens included cytomegalovirus (5 cases), Aspergillus species (3), Cryptococcus neoformans (3), Mycobacterium avium complex (2), Penicillium marneffei (1), Nocardia species (1), and Rhodococcus equi (1). CONCLUSIONS: PCP and pulmonary TB are the two leading pulmonary infections in Taiwanese HIV/AIDS patients. These findings should be taken into consideration when developing management strategies and public health policies.

Adolescent↗

[Respiratory infections during chemotherapy-induced aplasia].

Damage to local and systemic host defenses of the lung makes the immunocompromised patient vulnerable to inhaled microorganisms. When a pulmonary infiltrate occurs, the array of possibilities is very large including conventional and opportunistic agents. The type of underlying disease and its associated immunodeficiency allow a high degree of accurate pathogen prediction. Neutropenia is associated with Gram-negative bacilli pneumonia. Prolonged neutropenia increases the risk of invasive aspergillosis and other unusual mycotic agents. Cellular immunodeficiency is associated with intracellular microorganisms including Mycobacteria spp., Nocardia spp., Legionella spp., Rhodococcus equi, cytomegalovirus, Strongyloides stercoralis, Toxoplasma gondii, Histoplasma capsulatum, Coccidioides spp., Cryptococcus neoformans and Pneumocystis carinii, parasites such as Toxoplasma gondii and Strongyloides stercoralis, and virus such as cytomegalovirus, Herpes simplex or zoster, adenovirus, respiratory syncitial virus and measles. Humoral immunodeficiency predisposes to infection with encapsulated pathogens such as S. pneumoniae and Haemophilus influenzae. Chest computerized tomography scan and bronchoalveolar lavage are essential procedures for diagnosis. However, despite continuous progress in diagnostic methods, the specific etiology remains often unknown. Successful treatment depends on the type of pathogen, status of host defences and early adequate choice of antibiotic. Enhancement of host defences with growth factors and cytokines may decrease the incidence and improve the final outcome of respiratory infections in the immunocompromised host.

Anti-Bacterial Agents↗