Comparison of methods for recovery and enumeration of Campylobacter from freshly processed broilers.

Most traditional Campylobacter detection and enumeration procedures are difficult and time consuming. Estimations of Campylobacter populations by the most probable number (MPN) method are especially laborious. The objective of this collaborative study, performed in duplicate in Agricultural Research Service and Food Safety Inspection Service laboratories, was to compare two MPN procedures (utilizing different selective enrichment broths and plating media) to the direct plating technique for enumeration of Campylobacter from freshly processed (postchill, postdrip) broiler chicken carcasses. Results obtained from the direct plating of carcass rinse samples on Campy-cefex agar were not significantly different (P > 0.05) from an MPN procedure employing Hunt's Campylobacter selective enrichment broth followed by recovery on modified Campylobacter charcoal differential agar. However, both of these procedures provided significantly (P < 0.05) better recovery than a second MPN procedure using Rosef's selective enrichment broth followed by plating on Mueller-Hinton blood agar with antibiotics. The direct plating method offers a more simple, less expensive, more rapid alternative to traditional MPN procedures for estimating Campylobacter populations associated with freshly processed broiler carcasses.

Follicular center cell lymphoma with an extremely high content of T cells: case report with useful diagnostic techniques.

Follicular center cell lymphomas often contain a prominent population of T cells, most commonly in the interfollicular regions and with a helper immunophenotype. We report a case of follicular center cell lymphoma (follicular, mixed cell types) with a prominent population of T cells (normal CD4-CD8 ratio) in both the interfollicular and follicular regions. The prominent T-cell population resulted in misleading flow cytometric immunophenotypic findings. Immunoperoxidase stains (L-26, LN-2, and Bcl-2) confirmed the neoplastic follicular center cell origin and aided in subclassification.

Bartonella henselae neuroretinitis in cat scratch disease. Diagnosis, management, and sequelae.

OBJECTIVE: This study aimed to report the long-term outcomes of patients treated with an antibiotic drug combination for Bartonella henselae neuroretinitis. DESIGN: The study design was a retrospective case series. PARTICIPANTS: Seven consecutive patients with neuroretinitis and cat scratch disease participated. INTERVENTIONS: Patients underwent medical and ophthalmic evaluations. Blood cultures were obtained, and B. henselae antibody titers were measured. Tuberculosis, Lyme, toxoplasmosis, syphilis, and sarcoidosis were excluded. Patients received oral doxycycline 100 mg and rifampin 300 mg twice daily for 4 to 6 weeks and were observed for an average of 16 months (range, 10-24 months). Formal electrophysiologic testing was performed in three patients after resolution of neuroretinitis. MAIN OUTCOME MEASURES: The changes in ocular inflammation and visual function associated with treatment were recorded. Follow-up examinations and electrophysiologic testing documented sequelae. RESULTS: Patients presented following cat exposure with fever, malaise, and blurred vision. Decreased visual acuity (ranging from 20/40 to counting fingers) frequently was associated with dyschromatopsia and afferent pupillary defects. Ophthalmoscopic analysis showed signs of neuroretinitis, including nerve fiber layer hemorrhages, cotton-wool spots, multiple discrete lesions in the deep retina, and stellate macular exudates. B. henselae infection was confirmed with positive blood cultures or elevated immunofluorescent antibody titers or both. Therapy appeared to promote resolution of neuroretinitis, restoration of visual acuity, and clearance of bacteremia. After 1 to 2 years, two eyes had residual disc pallor, afferent pupillary defects, retinal pigmentary changes, and mildly decreased visual acuity. Electrophysiologic studies showed that when compared to the fellow eye, affected eyes had subnormal contrast sensitivity, abnormal color vision, and abnormal visually evoked potentials. Conversely, electroretinograms were normal in all subjects. CONCLUSIONS: B. henselae is a cause of neuroretinitis in cat scratch disease. Compared to historic cases, doxycycline and rifampin appeared to shorten the course of disease and hasten visual recovery. Long-term prognosis is good, but some individuals may acquire a mild postinfectious optic neuropathy.

Neuroretinitis, aseptic meningitis, and lymphadenitis associated with Bartonella (Rochalimaea) henselae infection in immunocompetent patients and patients infected with human immunodeficiency virus type 1.

Bartonella (Rochalimaea) henselae causes a variety of diseases, including bacillary angiomatosis, peliosis hepatis, lymphadenitis, aseptic meningitis with bacteremia, and cat-scratch disease (CSD). Cases of B. henselae-related disease were collected from September 1991 through November 1993. Patients with suspected CSD, unexplained fever and lymphadenitis, or suspected B. henselae infection who were seen in the Infectious Diseases Clinic at Wilford Hall Medical Center (Lackland Air Force Base, TX) underwent physical and laboratory examinations. In addition to three previously described cases, 23 patients with R. henselae-related infection were identified. The patients included 19 immunocompetent individuals presenting with lymphadenitis (11), stellate neuroretinitis (5), Parinaud's oculoglandular syndrome with retinitis (1), chronic fatigue syndrome-like disease (1), and microbiologically proven adenitis without the presence of immunofluorescent antibodies to B. henselae (1) and four patients infected with human immunodeficiency virus type 1 presenting with isolated lymphadenitis (1), diffuse upper-extremity adenitis (1), neuroretinitis (1), and aseptic meningitis (1). A couple with neuroretinitis and their pet cat, a persistently fatigued patient, and a patient with Parinaud's oculoglandular syndrome were shown to have bacteremia. Tissue cultures were positive for B. henselae in three recent cases of adenitis. Twenty-two patients were exposed to cats. This series further demonstrates the similarities between B. henselae-related diseases and CSD and identifies several new syndromes due to B. henselae.

Methods Used for Detection and Recovery of Escherichia coli O157:H7 Associated with a Food-Borne Disease Outbreak †.

The current Food Safety and Inspection Service method for detection and recovery of Escherichia coli O157:H7, (including modified EC broth with novobiocin (mEC+n) and a direct blot ELISA). was used to analyze beef and environmental samples during an investigation of a food-borne disease outbreak attributed to consumption of undercooked hamburger patties. Double-modified trypticase soy broth (dmTSB) and a commercially available dipstick immunoassay were also used to improve detection/recovery of E. coli O157:H7. A total of 1,115 beef and environmental samples was screened with the direct blot ELISA and the dipstick immunoassay; 178 presumptive-positive samples (by either or both of the screening methods) were subjected to recovery/isolation procedures. Toxigenic E. coli O157:H7 was recovered from 45 samples: 40 hamburger-patty samples produced on the epidemiologically identified date, 3 hamburger-patty samples produced on another date, and 2 beef briskets. The organism was not recovered from environmental samples. Limited quantitative analyses indicated that contaminated hamburger patties contained fewer than 4.3 CFU of E. coli O157:H7 per g. Atypical, toxigenic ornithine decarboxylase-negative E. coli O157:H7 and nontoxigenic sorbitol-positive E. coli O157:H29 were also recovered. Both enrichment broths gave strong positive reactions with the two immunoassay screening methods, but E. coli O157:H7 was recovered more often from mEC+n broth than from dmTSB. Both screening methods gave positive results for 44 of the 45 beef samples found to contain E. coli O157:H7. False-positive results were frequently observed with both screening methods.

A severe, unusual reaction to trimethoprim-sulfamethoxazole in patients infected with human immunodeficiency virus.

The clinical features of three patients with a life-threatening reaction to trimethoprim-sulfamethoxazole (TMP-SMZ) are presented along with seven other cases from the literature. All patients developed sudden fever and hypotension immediately after the administration of TMP-SMZ; usually this reaction occurred within approximately 2 weeks of completion of a previous course of the drug. All but one patient had a rash. Most patients were hypoxemic and developed diffuse pulmonary infiltrates. All patients responded rapidly to supportive care, while bacterial cultures remained negative. The presence, absence, or character of previous adverse reactions to TMP-SMZ did not predict subsequent severe reactions. Although its mechanism remains unclear, this reaction has features of both IgE-mediated anaphylaxis and cytokine (tumor necrosis factor)-mediated effects. We advise extreme caution, with close observation, when this drug is first readministered to patients who have experienced any TMP-SMZ-associated toxicity within the previous 6-8 weeks.

Coccidioides immitis presenting as a mycelial pathogen with empyema and hydropneumothorax.

A previously healthy Caucasian male developed hydropneumothorax and a pleural peel filled with pleomorphic, septate hyphae. The only organism grown from cultures of the lung and pleural fluid was Coccidioides immitis, confirmed by exoantigen testing. Spherule-endospore forms were produced, however, following injection of the arthroconidial tissue isolate into BALB/c mice. The patient had a positive immunodiffusion complement-fixation test and developed a positive coccidioidin skin test during therapy. He recovered following thoracotomy and wedge resection of the ruptured coccidioidal cavity, and therapy with amphotericin B followed by fluconazole. The sole presence of the mycelial form of the dimorphic fungus C. immitis in the pleural space may have been due to a low CO2 partial pressure at that site secondary to a bronchopleural fistula. The case shows a distinctive and uncommon presentation of coccidioidomycosis which demonstrates the specificity of both the immunodiffusion complement-fixation assay in diagnosing this disease and the exoantigen test in confirming culture results.

Pneumocystis carinii infection in germ-free rats: implications for human patients.

Pneumocystis carinii infections have been detected both serologically and histologically in untreated, germ-free and conventional rats killed immediately upon arrival from two commercial sources. Pneumocystis antigenemia was detected by counterimmunoelectrophoresis (CIE) and antibody was titered by indirect immunofluorescence. The data suggest that 1) P. carinii is enzootic in certain rat colonies; 2) in utero transmission is a distinct possibility; and 3) paucity of cysts does not rule out P. carinii, as trophozoites predominate in early or sub-clinical infections. Histologic data support the validity of CIE for noninvasive detection of P. carinii antigen. Infection with this agent may be missed by basing diagnosis upon the presence of cyst forms alone, and it may be more common than previously supposed. These data have significant implications for the natural history, diagnosis, and epidemiology of P. carinii with regard to the human host.

Age-related neoplastic and degenerative lesions in aging male virgin and ex-breeder ACI/segHapBR rats.

A variety of neoplastic and degenerative lesions were observed in 216 aged male breeder (to 24 months of age) and virgin ACI/segHapBR rats sacrificed from 24 to 40 months of age. The most common neoplasms were pheochromocytomas, pituitary tumors, interstitial cell tumors of the testis, and tumors of the skin and subcutis. Many rats had multiple endocrine tumors. Age-related prostate hyperplasias and tumors were reported previously in these rats. Most of these tumors increased in incidence with advancing age, with few differences between virgins and ex-breeders. Testicular atrophy and tumors were more common in younger ex-breeder rats than in young virgin rats, but tumors reached a similar incidence in older virgin rats. Focal hyperplastic lesions appeared to represent the earliest stages of neoplasia in pituitary and adrenal glands, thyroid, prostate, testis, and liver. Common age-related nonneoplastic degenerative lesions were found in various tissues.

Longevity and reproductive comparisons for male ACI and Sprague-Dawley rat aging colonies.

ACI male rats had a life span approximately one-half year greater than that of Sprague-Dawley male rats. For ACI male rats, median survival was 31.5 months for virgins and 30 months for breeders; for Sprague-Dawley male rats, median survival was 24.5 months for virgins and 25 months for breeders. There was increased fertility of aged ACI males relative to Sprague-Dawley males. ACI males, approximately 2 years old, sired an average of 3.8 litters during a 6-month breeding period, while Sprague-Dawley males of similar age sired an average of 0.9 litters within an equivalent period.

Age-associated lesions in barrier-reared male Sprague-Dawley rats: a comparison between Hap: (SD) and Crl:COBS[R]CD[R](SD) stocks.

Age-associated lesions were characterized in two outbred stocks of barrier-reared male Sprague-Dawley rats. Seventy-two virgin Hap:(SD) between 6-29 months of age and 113 retired breeder Crl:COBS[R]CD[R]CDR(SD) between 12-38 months of age were evaluated for the presence of lesions in all major organ systems. Rats of both stocks developed a spectrum of neoplastic, inflammatory and degenerative diseases with highest prevalence in the oldest age groups. In general, the shorter-lived Hap:(SD) rats had greater incidences and severity of lesions when compared to Crl:COBS[R]CD[R]SD of similar ages. Many of these differences were not apparent when the two stocks were compared over their respective life spans. The study provides baseline pathology data relevant to the use of these rats in gerontologic research.

Histogenesis and morphology of naturally occurring prostatic carcinoma in the ACI/segHapBR rat.

The prostates of 201 male virgin or breeder ACI (ACI/segHapBR) rats, 24 to 40 months of age were reviewed histologically, and the genesis of prostatic carcinoma was studied. At 24 months of age, 35 to 45 per cent of the rats had the earliest lesions, intraalveolar atypical hyperplasias. These lesions progressed to intraalveolar cribriform carcinomas which spread along alveoli and ducts. As the tumors enlarged, they became nodular and invaded the capsule or adjacent tissues. By 33 months, 95 to 100 per cent of the rats had intraalveolar prostatic atypical hyperplasias, and 35 to 40 per cent had invasive carcinomas. There was no difference between the incidence of these tumors in virgin or breeder rats. The ACI rat is unique model for studying the etiology and pathogenesis of naturally occurring prostatic cancer.