Clinical, laboratory, and environmental features of infant botulism in Southeastern Pennsylvania.

Forty-four cases of botulism occurred in infants in Southeastern Pennsylvania between 1976 and 1983. Forty-three were caused by Clostridium botulinum type B. Progressive weakness necessitated ventilatory support in 39 infants. Complications during hospitalization included otitis media in 13 patients and aspiration pneumonia in 11. Eight infants developed the syndrome of inappropriate secretion of antidiuretic hormone and two developed adult respiratory distress syndrome. One infant died of progressive bradycardia despite adequate control of ventilation. Manifestations of autonomic nervous system dysfunction recognized on admission to the hospital were constipation, distention of the urinary bladder, and decreased salivation and tearing. During hospitalization, some infants had unexpected fluctuations of skin color, blood pressure, and heart rate. Infants' strength improved despite persistent intestinal elaboration of toxin. C botulinum was isolated from seven of nine home or work environments sampled. All 44 infants were white and were receiving breast milk at the time of onset of symptoms. The majority had first feedings of nonhuman food substances within 4 weeks prior to onset of symptoms. Delineation of fecal flora in seven infants revealed predominance of enterobacteriaceae. Perturbations of intestinal flora during infancy, especially at weaning, may cause transient permissiveness to colonization by C botulinum.

Nontuberculous mycobacteria in adult patients with cystic fibrosis.

Because patients with cystic fibrosis (CF) may be predisposed to airway infections with unusual microorganisms, we screened the sputum of adult CF patients for mycobacterial organisms. Acid-fast bacilli (AFB) smears and mycobacterial culture were performed on 297 sputum specimens from 87 patients. Cultures for mycobacteria were frequently overgrown with other bacteria; 22.6 percent of cultures were contaminated. Despite this limitation of mycobacterial culture, 17 patients had at least one positive culture for a Mycobacterium other than tuberculosis (MOTT). Eleven patients were positive for Mycobacterium avium-intracellulare (MAI), two for MAI and M chelonei, three for M chelonei, and one for M fortuitum. None was positive for M tuberculosis. Patients with CF with MOTT were similar to patients with CF without MOTT; only a slightly different (older) age distribution was recognized. The clinical significance of MOTT was difficult to determine in any individual patient, but patients with positive AFB smears appeared more likely to suffer pathogenic effects. We conclude that MOTT is frequently recovered from adult CF patients in the southeastern United States. A specific risk factor for colonization and/or pathogenic infection in this patient group was not evident. The general prevalence and clinical pathogenesis in CF patients in the United States remains to be determined.

Inapparent transmission of Pseudomonas (Burkholderia) cepacia among patients with cystic fibrosis.

Pseudomonas cepacia is a significant pathogen in children and young adults with cystic fibrosis, and prevention of its acquisition has become an important goal in patient management. Although it is now clear that this bacterium can be transmitted from person to person, the frequency of this mode of acquisition and the measures required to prevent it are controversial. In this report we describe the use of a novel genotyping method to extend our previous investigation of person to person transmission of P. cepacia among patients with cystic fibrosis attending an educational program. Three (20%) of 15 individuals acquired P. cepacia after contact with a chronically colonized patient. Analysis revealed that the isolates recovered from the three newly colonized patients were the same as that from the index patient. We also demonstrated that pulmonary colonization with P. cepacia may not be detected by currently recommended culture methods for as long as 2 years after acquisition. These data indicate a need to develop more sensitive means of detecting P. cepacia colonization in order better to understand host-pathogen interaction and to optimize preventive strategies.

Utility of obtaining blood cultures in febrile neutropenic patients undergoing bone marrow transplantation.

Infection remains an important cause of morbidity and mortality after bone marrow or stem cell transplantation. To evaluate the role of obtaining blood cultures for intermittent or persistent fever in neutropenic patients on antibiotic therapy, we performed a retrospective chart review of 196 consecutive patients admitted to the Bone Marrow Transplant Unit at the University of North Carolina Hospitals from 1995 to 1998. From the cohort of 196 patients, 154 patients developed neutropenic fever. The initial blood culture was positive in 16 of 145 patients during the first fever episode giving a prevalence of 11%. From the total of 109 patients that had blood cultures drawn after day 1 of fever, five patients had blood cultures positive for a pathogen, a prevalence of 4.6%. In only one patient, did blood cultures drawn after day 1 identify an organism not present on day 1 (prevalence 0.9%). After reviewing the results in the first 105 patients, we changed our timing of collection of blood cultures. Forty-nine patients were treated in this manner and we found that the mean number of blood cultures decreased from 9.2 to 4.7 per patient without a change in the frequency of infectious complications or length of hospitalization.

Yersinia enterocolitica meningitis and osteomyelitis: a case report.

We present a case of a 45-yr-old black male who developed both meningitis and osteomyelitis due to Yersinia enterocolitica. This particular case was remarkable because the patient made a full recovery without long-term sequelae after therapy with IV chloramphenicol followed by oral trimethoprim-sulfamethoxazole.

Escherichia coli. EAEC, EHEC, EIEC, ETEC.

There are at least four different ways in which E. coli can cause diarrheal disease: invasion of the intestinal epithelium, enterotoxin production, STx production, and adherence with disruption of the normal functioning of the intestinal epithelium. Fecally contaminated food and water are the source of E. coli infections in humans. Travelers from industrialized countries with good sanitation systems are at risk for obtaining these organisms when they travel to the developing world, where these organisms are endemic. In the developing world, these organisms are a major cause of infant mortality. Infections in adults are usually self-limited and typically respond to oral rehydration therapy. Only in severe illness is antimicrobial therapy needed. Prevention of these infections requires good sanitation and food handling practices. In addition, travelers to the developing world should avoid certain types of food and contaminated water.

Effect of lindane on nitroreductase and dechlorinase enzyme activity in the gastrointestinal tract.

A previously reported acceleration of parathion metabolism in the gastrointestinal (GI) tract of lindane-pretreated rats could have been due to either a prolonged residence time of parathion or increased GI nitroreductase activity or both. Thus to determine the effect on GI nitroreductase and dechlorinase activity, 20 mg/kg lindane or 535 mg/kg neomycin were administered daily, by gavage, to weanling F-344 rats. Enzyme activity in the small intestine and cecum were assayed after 2 weeks and 5 weeks of treatment. Neomycin treatment inhibited the activity of both enzymes in the cecum but had no significant effect on enzyme activity in the small intestine, suggesting the presence of mucosal nitroreductase and dechlorinase in the small intestine. In contrast, lindane, which had no effect on enzyme activity in the cecum, significantly increased nitroreductase activity in the small intestine after treatment for 5 weeks. This increased nitroreductase may account for the previously reported lindane-parathion interaction and could influence the metabolism, toxicity, and risk assessment of many other environmental nitro-compounds that become toxic, mutagenic or carcinogenic upon reduction of their nitro-groups.

Evaluation of the latex agglutination test for detection of Clostridium difficile.

We compared two Clostridium difficile latex agglutination tests, Meritec from Meridian Diagnostic (Cincinnati, Ohio) and CDT from Becton-Dickinson (Cockeysville, Md), on 289 specimens submitted for tissue culture cytotoxicity using MRC-5 cells. When compared with CDT, the Meritec latex agglutination test had a sensitivity of 90% (26/29), a specificity of 97% (251/260), and a correlation of 96%. Meritec was compared with tissue culture cytotoxicity on 357 specimens. Meritec had a sensitivity of 77% (30/39), a specificity of 93% (298/318), and a correlation of 92%. Clinical review of 10 Meritec +/- tissue culture cytotoxicity minus patients revealed one likely, two probable, and seven doubtful cases of C difficile disease. In contrast, review of 10 Meritec +/- tissue culture cytotoxicity plus patients showed seven likely and three probable cases of C difficile disease. The Meritec is comparable with the CDT latex agglutination test, but is not nearly as sensitive as either tissue culture assay or culture for detection of C difficile disease. A positive latex agglutination test should be confirmed by a tissue culture cytotoxicity assay.

Survival of human immunodeficiency virus in blood culture systems.

The survival of human immunodeficiency virus (HIV) in three blood culture systems was examined. Cells of a continuous T-cell line (CEM) infected with HIV were inoculated into either Columbia or Middlebrook 7H12 broths, or a combination of an Isolator tube/Middlebrook broth. Virus viability studies were done by removing aliquots from these media at 0, 1, 2, and 7 days and cocultivating them with uninfected CEM cells. The HIV was still viable after two days' incubation in Middlebrook broth and after seven days in Columbia broth. When HIV-infected cells were held in the Isolator blood culture tube for 30 minutes before processing in Middlebrook broth, viable virus was detected only after two and seven days' incubation. However, if infected cells were held in the Isolator tube for 60 or 120 minutes, no virus could be detected after Middlebrook broth incubation. These data suggested that the Isolator system will inactivate HIV if blood from infected patients is held in it for 60 minutes or longer.

Clostridium difficile peritonitis in a neonate. A case report.

We describe a case of fatal peritonitis due to Clostridium difficile in a neonate. Although the patient had several clinical features that were compatible with the diagnosis of neonatal necrotizing enterocolitis, examination of the bowel at laparotomy disclosed that a mesenteric band caused the patient's underlying disease. Postmortem histopathologic tests revealed gram-positive rods in the wall of the small intestine. Clostridium difficile was the only organism recovered from an antemortem culture of peritoneal fluid and was also recovered from a postmortem blood culture.

The use of a commercially available enzyme immunoassay for the detection of Clostridium difficile toxin A.

A commercially available enzyme immunoassay (EIA) for the detection of Clostridium difficile toxin A (Premier Toxin A EIA, Meridian Diagnostics, Cincinnati, Ohio) was compared with tissue culture cytotoxicity assay, enterotoxigenic culture, and latex agglutination test for the laboratory diagnosis of C difficile-associated disease. When evaluated for detection of C difficile-associated disease using clinical specimens, EIA was the most sensitive (83.1%) and tissue culture cytotoxicity assay was the most specific test with EIA, tissue culture cytotoxicity assay and enterotoxigenic culture having similar correlation values (96.6, 96.1, 94.0%, respectively). The latex agglutination test was not as accurate (89.7% correlation) as the other three tests due mainly to its poor sensitivity (47.9%). The EIA is a rapid, easy-to-use alternative to tissue culture cytotoxicity assay for detection of C difficile-associated disease.

Microbiology of airway disease in patients with cystic fibrosis.

Individuals with cystic fibrosis have abbreviated life spans primarily due to chronic airway infection. A limited number of types of organisms are responsible for these infections, with Staphylococcus aureus and Pseudomonas aeruginosa being of primary importance. In the pre-antibiotic era, greater than 90% of deaths due to infection were caused by S. aureus and death usually occurred in the first 2 years of life. With the advent of effective antistaphylococcal therapy, life spans increased and P. aeruginosa became the pathogen of primary importance. P. aeruginosa isolates recovered from patients with cystic fibrosis have a unique phenotypic characteristic referred to as "mucoid." The mucoid phenotype is due to the production of a mucoid exopolysaccharide. A mucoid exopolysaccharide is believed to play a central role in the establishment of chronic pseudomonal lung infection in these patients. A third organism, Pseudomonas cepacia, has recently been detected in the airways of older patients with cystic fibrosis and is associated with increased mortality. The virulence of P. cepacia is not understood, but the organism is extremely refractory to antimicrobial therapy. Other bacteria, including Haemophilus influenzae and members of the family Enterobacteriaceae, appear to play a secondary role in airway infection. Aspergillus fumigatus is the most important fungal agent causing allergic bronchopulmonary disease. The role of viruses has only recently been examined. At least in some patients with cystic fibrosis, respiratory syncytial virus may be important in predisposing to subsequent bacterial infections.

Evaluation of the campyslide agglutination test for confirmatory identification of selected Campylobacter species.

The utility of a rapid latex slide agglutination test (Campyslide; BBL Microbiology Systems, Cockeysville, Md.) in detecting selected Campylobacter spp. was evaluated and compared with that of conventional identification methods. Isolated colonies suggestive of Campylobacter spp. were tested directly from primary selective media after incubation at 42 degrees C under microaerophilic conditions. Stock cultures of Campylobacter jejuni (n = 27) and C. coli (n = 3) were correctly confirmed to the genus level by latex agglutination when tested in pure cultures or isolated from seeded human feces. A total of 50 fresh clinical isolates of Campylobacter spp. (45 C. jejuni and 5 C. coli) were examined, with complete agreement observed between the latex test and conventional methods. Of 173 non-Campylobacter isolates tested from primary plates, only 1 rough strain of Pseudomonas aeruginosa produced a false-positive result. Although the manufacturer recommends a 30-min antigen extraction, 1 or 5 min was found to be sufficient. Also, confirmation could be achieved within 24 h of inoculation of clinical specimens, 2 days earlier than with conventional methods.

Importance of culture in laboratory diagnosis of Bordetella pertussis infections.

Nasopharyngeal secretions from 223 patients were examined for the presence of Bordetella pertussis and B. parapertussis by culturing on Regan-Lowe agar (J. Regan and F. Lowe, J. Clin. Microbiol. 6:303-309, 1977) and by direct fluorescent-antibody testing. B. pertussis was found in 38 patients; B. parapertussis was recovered from 2. Culturing was more sensitive (38 of 38 patients) than direct fluorescent-antibody testing (26 of 38 patients) for the detection of B. pertussis. Overgrowth by other organisms (7 of 223 patients) was uncommon. The patients with B. pertussis infections were generally less than 1 year old, had received no or one immunization, and had coughing spells but infrequently had whooping cough. Accurate diagnosis of B. pertussis infections should include culturing.

Nutritional requirements for synthesis of heat-labile enterotoxin by enterotoxigenic strains of Escherichia coli.

Optimal growth conditions have been established for production of heat-labile enterotoxin (LT) by both porcine and human strains of enterotoxigenic (ENT(+)) Escherichia coli. There were no unusual growth factor requirements, and some strains produced fairly high levels of LT in a basal salts medium containing 0.5% glucose if the pH was carefully controlled. Several amino acids markedly stimulated LT synthesis when added to the basal salts-glucose medium. Methionine and lysine were the most stimulatory for both human and porcine strains. Either aspartic acid or glutamic acid further enhanced LT synthesis in the presence of methionine and lysine, with aspartic acid being more stimulatory for porcine strains and glutamic acid more stimulatory for human strains. There were no apparent vitamin requirements and no unusual cations needed for toxin synthesis except that Fe(3+) was slightly stimulatory for porcine strains. The stimulation by Fe(3+) was observed only in the presence of the three amino acids, suggesting that the effect was indirect rather than on toxin synthesis. The carbon source also influenced the yield of LT. Glucose supported maximal synthesis, but other carbon sources which exhibit a high degree of catabolite repression also supported high levels of synthesis. Little or no LT was released below pH 7.0; therefore, because the pH drops during growth from 7.5 to 6.8, even in highly buffered media, it was necessary to adjust the pH to 8.0 to effect complete release of cell-associated toxin. The defined medium containing three amino acids reduced the amount of UV-absorbing material in culture supernatants about fivefold and increased LT activity for various strains from two- to fivefold over a complex Casamino Acids-yeast extract medium. Conditions found to be optimal for synthesis of LT were inhibitory for the heat-stable enterotoxin.

Effect of imipenem-cilastatin therapy on fecal flora.

Alteration of fecal flora was prospectively studied in 21 children receiving imipenem-cilastatin therapy under protocol for therapy of infections. Although no profound reduction in facultative or anaerobic flora was observed, qualitative and quantitative increases in organisms which were resistant or less susceptible to imipenem occurred. Of 21 patients, 13 (62%) had increases in counts of Enterococcus spp. of at least 10(3) organisms per g (wet weight) of stool, and 7 (33%) had acquisition of or similar increases in counts of Candida species. No change in susceptibility of isolates to imipenem was demonstrable during therapy. However, the MICs for 50 and 90% of the strains of Enterococcus spp. (2 and 8 micrograms/ml, respectively) were higher than those previously reported.

Recovery of resistant enterococci during vancomycin prophylaxis.

We report a case of a patient undergoing hemodialysis who developed a wound infection and subsequently bacteremia with a strain of vancomycin-resistant enterococcus identified as Enterococcus gallinarum. He had been receiving vancomycin prophylaxis before developing these infections. Both isolates were susceptible to ampicillin, rifampin, teicoplanin, and daptomycin (LY146032).

Comparative in vitro activity of A-56268 (TE-031), a new macrolide antibiotic.

The in vitro activity of A-56268 (TE-031) was determined by either standard agar dilution or macrobroth tube dilution and compared with erythromycin and other antimicrobial agents against 329 clinical aerobic and anaerobic bacterial isolates. A-56268 showed good to excellent in vitro activity against methicillin-sensitive Staphylococcus aureus, Neisseria meningitidis, and most anaerobes tested with the exception of Bacteroides fragilis isolates. A-56268 had relatively poor activity against coagulase-negative staphylococci and methicillin-resistant Staphylococcus aureus. Except for Haemophilus spp., the activity of A-56268 was similar to or more potent than erythromycin against all other isolates tested. A-56268 did not have significant bactericidal activity against any of the isolates examined.

Biotype of Haemophilus influenzae: correlation with virulence and ampicillin resistance.

Biotype and serotype were determined for 473 isolates of Haemophilus influenzae from 399 children. Patients with invasive disease usually had serotypable (86%) and biotype 1 (80%) isolates. Respiratory isolates from well children and children whose illness was not caused by H. influenzae were rarely serotypable (1%) or biotype 1 (8%). Respiratory isolates from children whose illness was possibly or probably related to H. influenzae and isolates from children with cystic fibrosis were more frequently biotype 1, serotypable, or both (P less than 0.01 for all comparisons). Ten (67%) of 15 children with acute otitis media due to H. influenzae had tympanocentesis isolates which were biotype 1; only one isolate was serotypable. Isolates from inflamed conjunctivae had biotypes and serotypes similar to respiratory isolates from well children. Ampicillin resistance was less frequent among biotype 1 isolates (9%) compared with other biotypes (19%) (P less than 0.01). The data suggest that H. influenzae is biochemically heterogeneous and that noncapsular factors, frequently predictable by biotype, contribute to virulence.