Allergen-specific leukocyte adherence inhibition (LAI) assay: sensitivity, specificity and mechanism.

An allergen-specific tube leukocyte adherence inhibition (LAI) assay has been developed in order to study the mechanism by which leukocytes lose their normal property of adherence to glass. Peripheral blood leukocytes (PBL) from 27 individuals allergic to Dermatophagoides farinae (DF), 10 with seasonal rhinitis not induced by DF and 49 non-allergic healthy volunteers were challenged in vitro with DF and a non-relevant allergen, Artemisia vulgaris (AV) and then assayed for the ability to adhere to glass tubes. Challenge by DF, but not by AV, resulted in loss of adherence by PBL from patients allergic to DF, but not in those of normal controls. The specific LAI response was dose-dependent and occurred only when a critical dose of 0.5 X 10(3) was employed. Following in vitro challenge with DF, radio-immunoassay using an antiserum to LTC4 detected immunoreactive material in supernatants of PBL from DF-allergic individuals. When highly enriched mononuclear cells from non-allergic individuals were armed with cytophilic allergen-specific IgE and challenged with the specific allergen, they lost the property of glass adherence and released a substance that was immunoreactive with LTC4. The results suggest that the chain of events leading to the LAI response in PBL from allergic individuals involves primary recognition of the allergen by specific IgE antibodies bound to receptors on mononuclear cells. The cells are thus triggered to synthesize cysteinyl-containing leukotrienes which mediate the LAI phenomenon. The results suggest that this assay may be used to study allergen-antibody interaction and the subsequent events leading to the clinical picture of atopic diseases.

Uriscreen, a rapid enzymatic urine screening test: useful predictor of significant bacteriuria in pregnancy.

OBJECTIVE: To establish the reliability of a new rapid enzymatic screening test, the Uriscreen, in the detection of significant bacteriuria in pregnancy. METHODS: During a 6-month period, from July 1 to December 30, 1993, 313 consecutive pregnant patients were evaluated. Randomly voided, midstream, clean-catch urine specimens were used. Each sample was tested by routine laboratory culture and four rapid screening tests: the nitrite and leukocyte esterase dipstick, microscopic examination for pyuria, and the Uriscreen test. Results of the four rapid tests were compared with those of the urine culture. RESULTS: Twenty-four women (7.6%) had urine culture results indicating significant bacteriuria. The sensitivity of the nitrite test, the leukocyte esterase test, and a microscopic examination for pyuria was low (37, 52, and 56%, respectively). The Uriscreen test showed very high sensitivity (100%), lower specificity (81%), a high predictive value of negative results (100%), and a low positive predictive value (30%). CONCLUSIONS: The Uriscreen test is a reliable alternative to culture screening of all pregnant patients. A policy of performing a urine culture during pregnancy only on patients with a positive Uriscreen test will save as much as 80% of unnecessary cultures.

Evaluation of two rapid tests for detection of maternal endocervical group B streptococcus: enzyme-linked immunosorbent assay and gram stain.

OBJECTIVE: To establish the reliability of two rapid tests for detection of group B streptococcus, the new enzyme-linked immunosorbent assay (ELISA) and the Gram stain. In addition, we wished to determine whether the combination of these tests would increase test sensitivity. METHODS: During a 2-year period, cervical secretions from 660 patients who presented with either premature rupture of membranes or preterm labor at a gestational age of 37 weeks or less were tested by three methods: the Equate ELISA test, a Gram stain smear, and a culture for group B streptococcus. Results of the rapid tests were compared with the corresponding culture results. RESULTS: Cultures were positive for group B streptococcus in 50 patients, a prevalence of 7.5%. The sensitivity for the Equate ELISA test was 24% and for the Gram stain, 20%. Specificity was 95 and 89%, respectively. When results of these tests were combined, the sensitivity increased to 26%. Both rapid tests yielded a high rate of false positives. In more than 50% of false-positive cases, bacteria other than group B streptococcus were isolated. CONCLUSION: Neither the Gram stain nor the Equate ELISA test is sensitive enough to be used as a screening test for the identification of group B streptococcus. Furthermore, the combination of both rapid tests yielded only a slight increase in sensitivity. The high false-positive rate of the ELISA test seems to be related to a cross-reactivity of the anti-group B streptococcal antibody with other cervical bacteria.

Enhanced urinary trypsin inhibitory activity in gentamicin-induced nephrotoxicity in rats.

We delineated in rats, the relationship between trypsin inhibitory activity in the urine and the nephrotoxic effects of gentamicin, eg, proteinuria and deterioration of glomerular filtration rate (GFR), measured by creatinine clearance. Gentamicin, 70 mg/kg per day, was injected intraperitoneally for 6-10 successive days. Serum and urine gentamicin levels were determined by a microbiological test. Trypsin inhibitory activity was assayed by the casein digestion method. The results showed a steady increase in urinary trypsin inhibitory activity starting from the fourth injection day. The increased levels of urinary trypsin inhibitory activity were associated with increased levels of urinary gentamicin excretion (r = 0.36, p less than 0.02, n = 50 after the fourth injection day), and were significantly higher than in control groups (p less than 0.001). The urinary trypsin inhibitory activity was inversely correlated with the GFR (r = -0.45, p less than 0.01, after the second injection day). The serum trypsin inhibitory activity remained unchanged throughout the study period in all groups. These data suggest that increased urinary trypsin inhibitory activity may be involved in the pathogenesis of gentamicin-induced nephrotoxicity.

Turbidimetric determination of blood aminoglycoside levels by growth curve analysis.

A procedure to assay rapidly blood aminoglycoside levels was developed based on growth curve analysis of continuous absorbance measurements of a bacterial test strain. Of the means available for monitoring bacterial growth quantitatively, turbidimetric measurement was selected because it can be used to perform a clinical assay in less than 4 hr. Continuous turbidimetric measurements provide information as soon as the antimicrobial agent affects growth, which often occurs within 60 min of the start of an assay. Several bacterial isolates were evaluated before Staphylococcus aureus (MHMC 386) was chosen as the test microorganism. This isolate was quite sensitive to the aminoglycoside antibiotics, permitted the rapid measurement of blood levels of amikacin, gentamicin, kanamycin, and tobramycin, and exhibited a linear dose-response relationship of turbidity over a wide range of antibiotic concentrations.

Complications associated with genital colonization in pregnancies with and without cerclage.

Cultures from the cervical milieu were taken from 24 antibiotic-treated patients (group A) and from 25 patients with no antibiotic treatment (group B). Both groups had undergone cerclage and were compared to 30 randomly chosen pregnant patients without cerclage (group C). Positive cultures were obtained in 70.8% and 48% before cerclage and in 66.7% and 68% after cerclage in groups A and B, respectively. These were not significantly different from group C (56.7%). Escherichia coli was found in over 75% of positive cultures. The rate of premature deliveries and premature rupture of the membranes were significantly higher in the cerclage groups. Maternal morbidity was significantly higher in group A compared to B and C. Our data suggest that bacterial colonization of the cervix and the vagina is not influenced by cerclage and antibiotics. It is concluded that cervical cerclage is associated with increased morbidity, therefore it is indicated only for definite anatomic and/or functional defects.

Once-daily intramuscular ceftriaxone in the outpatient treatment of severe community-acquired pneumonia in children.

Ceftriaxone, a broad spectrum third-generation cephalosporin with a half-life of six to eight hours, was evaluated prospectively in 147 children with severe community-acquired bacterial pneumonia during the period 11/15/88-5/15/89. Thirty-nine of the children had been unsuccessfully treated with vanous oral antibiotics prior to admission [corrected]. All the patients were initially hospitalized and started on once a day intramuscular ceftriaxone. Mean duration of ceftriaxone therapy was five days. Pathogens were recovered from blood cultures of 17 (11.6%) patients and included S. pneumoniae (13 patients), H. influenzae (three, all resistant to ampicillin) and S. viridans (1) [corrected]. All isolates were sensitive to ceftriaxone. An additional patient had L. pneumophila diagnosed by serology. Cure was achieved in 142 (96.6%) patients; improvement was usually observed within 24-48 hours. After 48 hours, 121 (82.2%) children could be discharged and continued the therapy on ambulatory basis. Based on previous experience we estimated that 383 hospitalization days were saved. No serious side effects were observed. Five patients were considered therapeutic failures; two of them developed empyema and one of them required repeated drainage procedures. A third patient experienced a relapse of pneumonia shortly after completion of therapy. The other two remained febrile for more than seven days; their subsequent improvement was unrelated to the antibiotic therapy, suggesting a viral or mycoplasmal syndrome. Our data suggest that once daily intramuscular ceftriaxone can be successfully used for the outpatient treatment of most community-acquired severe bacterial pneumonias in children. In our opinion it represents the treatment of choice for patients who failed treatment with other antimicrobials and are clinically stable enough not to require hospitalization.

[Penicillin VK absorption during fasting and after eating].

The absorption of penicillin VK (Rafapen) was evaluated in 12 children, 3-16 years.old, with infections due to penicillin-sensitive organisms. In each, 50 mg/kg of Rafapen was given after an overnight fast, and the next day the same amount was administered after a standard hospital breakfast. Blood samples were drawn before and 30, 60 and 90 min after the drug was given. Serum penicillin levels were determined by comparing the inhibition of growth on plates of Staphylococcus aureus (Oxford strain), with that of standard penicillin G concentrations. The serum levels after the overnight fast were higher, 4.75 U/ml, as compared to 3.38 U/ml 30 min after the drug was given following breakfast. This increase was abolished at 60 and 90 min, when the serum levels were 1.96 and 1.05 U/ml, respectively. We advise the use of oral penicillin VK in infections due to penicillin-sensitive organisms, without regard to feeding schedule.

Sputum cytology in suspected cases of carcinoma of lung (Sputum cytology a poor man's bronchoscopy!).

AIMS: To evaluate the role of sputum cytology in the diagnostic work-up of patients with suspected lung cancer SETTINGS AND DESIGN: Spontaneously produced fresh sputum was analyzed in clinically suspected cases of lung cancer. MATERIALS AND METHODS: Spontaneously produced fresh sputum was analyzed in 36 clinically suspected cases of lung cancer. It was carried out using the "fresh pick and smear" method, which employs examination of sputum for blood-tinged, discolored or solid particles and preparation of thin and even smears from these selected portions. STATISTICAL ANALYSIS USED: Average and means. RESULTS: Sensitivity of sputum cytology was 60%, which increased with an increase in the number of samples examined. CONCLUSIONS: Sputum cytology in suspected cases of carcinoma of lung is a useful diagnostic tool. It may be called as a poor man's bronchoscopy.

Assessment of a self-contained solid phase enzyme linked immunoassay (ImmunoComb) for the determination of serum total IgE.

A semiquantitative method (ImmunoComb) for measuring total serum IgE is described and compared with a standard radioimmunoassay (PRIST). ImmunoComb, based on a solid-phase enzyme-linked immunoassay, is self-sufficient and does not require any expensive laboratory equipment. Comparison of these two assays revealed an almost absolute agreement between them (correlation coefficient = 0.95). Furthermore, the ImmunoComb assay also demonstrated its rapidity and temperature independence while maintaining a recovery of 90% to 102%.

Esculin hydrolysis reaction by Escherichia coli.

The literature contains variable reports concerning the hydrolysis of esculin by members of the family Enterobacteriaceae and particularly Escherichia coli. We examined 113 strains of fresh clinical isolates of E. coli and assessed the ability of colonies in a population to hydrolyze esculin with and without preincubation in inducible substrates at 24, 48, and 72 h. The number of strains capable of fermenting salicin, a sugar with a beta-glucoside linkage like esculin, was studied under the same conditions. A strip test that measured the presence of the constitutive glucosidase was also performed with and without preincubation in inducible substrates. No E. coli strain was able to produce constitutive enzyme; preincubation in esculin and salicin resulted in an induction of the beta-glucosidase. The number of colonies able to hydrolyze esculin increased with time. Only those strains preincubated in esculin or salicin were able to produce a positive constitutive strip test. Because the beta-glucosidase of E. coli is inducible, one should employe, when using growth media, a light inoculum obtained by touching the top of a colony with a bacteriological wire and read the reaction between 18 and 24 h, or perform a rapid strip or spot test.

Immunoglobulin levels in children with celiac disease: variations with age and diet.

Serum immunoglobulins were evaluated in 110 children with celiac disease ranging in age from three months to 15 years. IgG, IgM and IgA were evaluated in all the patients when they were on either a normal or a gluten-free diet and the findings were analyzed by age and type of diet. IgG and IgM levels were generally higher than normal. The type of diet did not affect the results. IgA levels were higher in untreated (normal diet) than in treated (gluten-free diet) celiac patients or normal subjects. The IgA levels returned to normal when the patients were on a gluten-free diet. The variations in immunoglobulin levels among the different age groups of celiac patients reflect the normal variations in serum immunoglobulins with age. It is suggested that the higher IgA levels in untreated celiac disease patients are evidence of chronic stimulation of the B cell immune system and that this could be a factor in the high incidence of lymphoreticular abnormalities and malignant tumors in adults with celiac disease.

Comparison between the combination of azlocillin-gentamicin and ampicillin-gentamicin in the treatment of a nursery population.

Newborn, and particularly premature infants are prone to life-threatening infections. The combination of ampicillin-gentamicin (AM-G) has been used extensively in neonatal intensive care units (NICU). Because resistant bacteria emerged, a new drug--an acylureidopenicillin, azlocillin, with a wide antibacterial spectrum--has been developed. A prospective randomized study was performed in order to evaluate the combination of AM-G vs. azlocillin-gentamicin (AZ-G). Thirty neonates received AM-G and 28 received AZ-G. Definite infection was found in 15 AM-G patients and in 10 AZ-G patients. In these patients, the antibiotic regimen was changed in six of the AM-G and in one of the AZ-G patients. In each of the two treatment groups, one very-low-birth-weight baby died due to overwhelming sepsis. In vitro sensitivity to AZ-G was higher than to AM-G, according to azlocillin blood levels obtained. Infants weighting less than 2,350 g had lower clearance and volume of distribution than did infants weighing greater than 2,350 g. The serum half-life was approximately the same in both groups. It appears to be that in the NICU, the combination of AZ-G may be more effective than the AM-G combination.

Necrotizing enterocolitis associated with rotavirus infection.

Infection has been widely reported as one of the factors usually incriminated in the development of necrotizing enterocolitis (NEC) in a previously ischemic bowel. Gram-negative bacteria have previously been implicated as pathogens in this dangerous entity, for which neonates are at high risk. However, viral infections have rarely been reported in connection with NEC. Rotavirus was identified in the stools of two premature infants who developed the full-blown picture of NEC in the Neonatal Intensive Care Unit (NICU) at Kaplan Hospital, Rehovot. Both cases occurred within a period of 3 months, during the winter season. During that time, rotavirus was diagnosed in the stools of 10 other infants admitted to the NICU. The detection of rotavirus in the stools of the two premature infants with NEC observed by us strongly suggests that rotavirus should be included in the list of infectious agents associated with the development of NEC.

Initial testing of a novel urine culture device.

The Diaslide urine culture device consists of a hinged case containing two opposing agar media separated by a sampler with a handle at one end and two bent sampler tips at the opposite end. The tips of the sampler are first dipped into the urine. The sampler is then pulled out through the casing, simultaneously inoculating both agar surfaces with a streaking dilution. As a result, individual colonies can be observed even when bacterial concentrations exceed 10(6) CFU/ml. The number of colonies on the Diaslide correlated linearly with CFU per milliliter as determined by dilution plating. The clinical performance of the Diaslide was compared with those of ordinary dipslides and conventional cultures with a sample of 473 prescreened hospital urine specimens. The sensitivity, specificity, and positive predictive value of Diaslide versus those of culture at the 10(4)-CFU/ml cutoff level were 97.5, 98.3, and 98.3%, respectively, compared with 98.8, 95.7, and 97.2%, respectively, for dipslide versus culture. Similar results were found at the 10(5)-CFU/ml cutoff level. Only 5.5% of the Diaslides required subculturing, compared with 14.7 and 9.4% of the dipslides and conventional cultures, respectively. The Diaslide proved more convenient than an ordinary dipslide for sampling low volumes of urine. These data suggest that the Diaslide is a simple, effective device for culturing of urine specimens.

Acute cholecystitis caused by Campylobacter jejuni.

An 83-year-old man with acute cholecystitis caused by Campylobacter jejuni is described. The patient was cured after undergoing cholecystectomy and intravenous ofloxacin therapy.

Prenatal diagnosis of Meckel syndrome: alpha-feto protein and beta-trace protein in amniotic fluid.

Meckel syndrome was diagnosed prenatally by alpha-feto protein and beta-trace protein determinations in amniotic fluid. No central nervous system anomalies were detected in the affected fetus, who presented with large polycystic kidneys and polydactyly. An excessive synthesis of these fetal proteins by the dysplastic kidneys is suggested, allowing for the possibility of prenatal diagnosis of polycystic kidneys in families at risk for this disease. The present family emphasized the importance of amniocentesis in pregnancies at risk for Meckel syndrome, regardless of the presence of a defect in neural tube closure.

Sepsis at a neonatal intensive care unit: a four-year retrospective study (1989-1992).

During the 4-year period 1989-1992, 18,227 neonates were born at Kaplan Hospital and 614 (3.4%) were admitted to the neonatal intensive care unit. During this period, 120 episodes (6.6/1000 live births) of neonatal sepsis were recorded in 109 neonates (6/1000 live births). The incidence of early-onset sepsis was 19/109 (17%). The main pathogens of early-onset sepsis were S. agalactiae (42%) and E. coli (32%). Seven of the 8 S. agalactiae cases were recorded during 1989-1990. The main pathogens of late-onset sepsis were Klebsiella spp. (31%), coagulase-negative staphylococci (18%) and Candida spp (16%). There were 11 cases (10%) of meningitis, 5 due to Klebsiella spp. The overall fatality rate due to sepsis was 14% (0.8/1000 live births) with an early-onset sepsis death rate of 37%. The mortality from S. agalactiae sepsis was 63%. The main trends recorded during the period of the study were 1) the emergence of S. agalactiae as the main pathogen of early-onset sepsis, followed by a sharp decrease in its incidence during the last part of the study, 2) the emergence of extremely virulent, multi-antibiotic-resistant Klebsiella organisms, and 3) the persistent high incidence of Candida sepsis.

An outbreak of antibiotic multiresistant Klebsiella at the Neonatal Intensive Care Unit, Kaplan Hospital, Rehovot, Israel, November 1991 to April 1992.

From November 1991 through April 1992, 8 infants developed systemic infections due to antibiotic multiple resistant Klebsiellaa (MRK). All were premature and 6 of the 8 weighed less than 1100 g; 7 of the 8 had received previous antibiotic therapy. Five infections occurred during the first week of life. MRK were isolated from blood (8 cases), tracheal secretions (TS-6), stool (3), and CSF (1). All Klebsiella blood isolates were resistant to ampicillin, mezlocillin, and cefotaxime, 7 of 8 to ceftazidime and amikacin, and 4 of 7 to aztreonam; all isolates were sensitive to quinolones and imipenem. Four infants died. In all 4 of the isolates, they were sensitive only to quinolones and imipenem, and the empiric therapy used for suspected sepsis proved to be inappropriate. The outbreak was terminated by temporary closure of NICU in May 1992. Strict hand washing practices were reemphasized, and the previous empiric antibiotic protocol used for suspected sepsis (mezlocillin plus amikacin, and lately ceftazidime plus amikacin) was changed to imipenem and amikacin in the risk population. At closure, 5 additional infants had MRK in stools and/or tracheal suction specimens. Development of MRK organisms should dictate a rational use of empiric antibiotics for neonatal infections in NICU.