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Objective: To determine the effect of peak inspiratory pressure (PIP) and positive end-expiratory pressure (PEEP) on the development of bacteremia with Klebsiella pneumoniae after mechanical ventilation of intratracheally inoculated rats., Design: Prospective, randomized, animal study., Setting: Experimental intensive care unit of a University., Subjects: Eighty male Sprague Dawley rats., Interventions: Intratracheal inoculation with 100 microliters of saline containing 3.5-5.0 x 10(5) colony forming units (CFUs) K. pneumoniae/ml. Pressure-controlled ventilation (frequency 30 bpm; I/E ratio = 1:2; FIO2 = 1.0) for 180 min at the following settings (PIP/PEEP in cmH2O): 13/3 (n = 16); 13/0 (n = 16); 30/10 (n = 16) and 30/0 (n = 16), starting 22 h after inoculation. Arterial blood samples were obtained and cultured before and 180 min after mechanical ventilation and immediately before sacrifice in two groups of non-ventilated control animals (n = 8 per group). After sacrifice, the lungs were homogenized to determine the number of CFUs K. pneumoniae., Measurements and Results: The number of CFUs recovered from the lungs was comparable in all experimental groups. After 180 min, 11 animals had positive blood cultures for K. pneumoniae in group 30/0, whereas only 2, 0 and 2 animals were positive in 13/3, 13/0 and 30/10, respectively (p < 0.05 group 30/0 versus all other groups)., Conclusions: These data show that 3 h of mechanical ventilation with a PIP of 30 cmH2O without PEEP in rats promotes bacteremia with K. pneumoniae. The use of 10 cmH2O PEEP at such PIP reduces ventilation-induced K. pneumoniae bacteremia.

In this study, we determined the efficacy of various dosing regimens for erythromycin and azithromycin against four pneumococci with different susceptibilities to penicillin in an in vitro pharmacokinetic model and in a mouse peritonitis model. The MIC was 0.03 microg/ml, and the 50% effective doses (determined after one dose) of both drugs were comparable for the four pneumococcal strains and were in the range of 1.83 to 6.22 mg/kg. Dosing experiments with mice, using regimens for azithromycin of one to eight doses/6 h, showed the one-dose regimen to give the best result; of the pharmacodynamic parameters tested (the maximum drug concentration in serum [Cmax], the times that the drug concentration in serum remained above the MIC and above the concentration required for maximum killing, and the area under the concentration time curve), Cmax was the best predictor of outcome. The bacterial counts in mouse blood or peritoneal fluid during the first 24 h after challenge were not correlated to survival of the mice. The serum concentration profiles obtained with mice for the different dosing regimens were simulated in the in vitro pharmacokinetic model. Here as well, the one-dose regimen of azithromycin showed the best result. However, the killing curves in vivo in mouse blood and peritoneal fluid and in the vitro pharmacokinetic model were not similar. The in vitro killing curves showed a decrease of 2 log10 within 2 and 3 h for azithromycin and erythromycin, respectively whereas the in vivo killing curves showed a bacteriostatic effect for both drugs. It is concluded that the results in terms of predictive pharmacodynamic parameters are comparable for the in vitro and in vivo models and that high initial concentrations of azithromycin favor a good outcome.

Background: The unexpected conversion to HBsAg seropositivity of three cardiac allograft recipients prompted us to conduct a multidisciplinary study to identify the source, transmission mode, and extent of the hepatitis B virus (HBV) infection among the 256 cardiac allograft recipients of our hospital., Methods: All recipients were retrospectively screened for serum markers of HBV infection. A selected genomic region defining subtypes of the viruses involved was amplified and sequenced. An epidemiologic case-control study for possible risk factors was conducted to identify the mode of transmission., Results: Eighteen additional HBV-infected patients were identified, none of whom had shown symptoms of HBV infection. The involvement of one virus (subtype ayw 3) was shown in 20 of the 21 HBV-infected patients. This virus is found in less than 10% of HBV-infected individuals in The Netherlands. The demonstration of a common source of infection, combined with results of the epidemiologic study, identified posttransplantation endomyocardial biopsy procedures as the most likely mode of transmission. However, we also found evidence of secondary virus transmission by cardiac catheterization procedures to nonallograft recipients., Conclusions: The immunosuppressive therapy practiced in these patients to prevent allograft rejection may have not only facilitated virus transmission by causing high levels of viremia but also left the spreading of HBV undetected by causing a subclinical course of the infection. These findings stress the necessity of strict hygienic precautions during intravascular diagnostic procedures and indicate that vaccination against and routine monitoring for certain bloodborne infections in cardiac allograft recipients should be considered.

Objective: To establish a tobramycin dosing schedule for neonates of various gestational ages., Methods: This was a retrospective study with prospective validation. A retrospective study in 470 neonates, with suspected septicemia in the first week of life, was performed. All patients received tobramycin according to the following scheme: neonates with a gestational age of less than 28 weeks received 3.5 mg/kg every 24 hours, neonates from 28 to 36 weeks received 2.5 mg/kg every 18 hours, neonates older than 36 weeks received 2.5 mg/kg every 12 hours. Trough and peak tobramycin serum levels were determined before drug administration and 30 minutes after the fourth dose. Tobramycin data were analyzed according to a one-compartment open model with use of NONMEM population pharmacokinetic software. Individual empirical Bayes estimates were generated on the basis of the population estimates and used to calculate predicted peak and trough levels for different doses and dosing intervals. To establish an optimal dosing regimen, target trough levels were set at below 2 mg/L and target peak levels were set above 5 to 10 mg/L. The dosing regimen was prospectively evaluated in 23 patients., Results: Of the 470 patients, 19.1% of measured peak and 32.8% of measured trough tobramycin serum levels were outside the desired therapeutic range, and 48.8% of neonates with a gestational age of less than 28 weeks had an aberrant trough level. With use of population estimates, the following dosing regimen was recommended: gestational age below 32 weeks, 4 mg/kg every 48 hours; gestational age between 32 and 37 weeks, 4 mg/kg every 36 hours, gestational age above 37 weeks, 4 mg/kg every 24 hours. With this dosing schedule, predicted peak levels were higher than 5 mg/L in 95.1% of the neonates. Predicted trough levels were higher than 2 mg/L in 1.9% of the neonates and higher than 1 mg/L in 7.6%. Prospectively measured peak levels were higher than 5 mg/L in all but one infant. Measured trough levels were higher than 2 mg/L in three patients and marginally higher than 1 mg/L in four patients., Conclusions: With the use of this proposed schedule, taking into account differences in gestational ages, predicted peak levels will be therapeutic, whereas predicted trough levels will minimize toxicity.

The molecular epidemiology of Pseudomonas aeruginosa infection in cystic fibrosis (CF) siblings was analysed by DNA fingerprinting using arbitrary primed polymerase chain reaction. A total of 306 strains collected from six pairs of siblings over a period of 20-126 months (median 64) was studied. Fifty-four different P. aeruginosa genotypes were recognized. Two out of six pairs of siblings were ultimately colonized by identical strains, and it was shown that a single P. aeruginosa clone can persist in an individual patient for over ten years. No overlap in P. aeruginosa genotypes was encountered between families, whereas in all families at least transient cross-colonization with the same genotype was observed. This finding demonstrates that P. aeruginosa cross-infection or acquisition of the same strain from an identical environmental source exists within the family situation, but does not always result in a long-term colonization by identical genotypes in all family members suffering from CF.

Objective: To test the hypothesis that perioperative elimination of nasal carriage of Staphylococcus aureus using mupirocin nasal ointment reduces the surgical-site infection (SSI) rate in cardiothoracic surgery., Design: Unblinded intervention trial with historical controls., Setting: A university hospital, tertiary referral center for cardiothoracic surgery., Patients: Consecutive patients undergoing cardiothoracic surgery between August 1, 1989, and February 1, 1991 (historical control group), and between March 1, 1991, and August 1, 1992 (intervention group)., Results: The historical control group consisted of 928 patients and the intervention group of 868, of whom 752 actually were treated. The 116 patients who were unintentionally not treated were considered as a concurrent control group. In the intention-to-treat analysis, a significant reduction in SSI rate was observed after the intervention (historical-control group 7.3% and intervention group 2.8%; P < .0001). The SSI rate in the concurrent control group was significantly higher than in the treated group (7.8% and 2.0%, respectively; P = .0023). Resistance of S aureus to mupirocin was not observed., Conclusion: The results of this study indicate that perioperative elimination of nasal carriage using mupirocin nasal ointment significantly reduces the SSI rate in cardiothoracic surgery patients and warrants a prospective, randomized, placebo-controlled efficacy trial. This preventive measure may be beneficial in other categories of surgical patients as well.

1. The use of pulmonary surfactant has been proposed as a vehicle for antibiotic delivery to the alveolar compartment of the lung. This study investigated survival rates of mice with a respiratory Klebsiella pneumoniae infection treated intratracheally with tobramycin using a natural exogenous surfactant preparation as vehicle. 2. At day 1 after infection, animals were injected intratracheally with 20 microliters of the following solutions: (1) a mixture of surfactant (500 micrograms) and tobramycin (250 micrograms); (2) tobramycin (250 micrograms) alone; (3) surfactant (500 micrograms) alone; and (4) NaHCO3 buffer (control, sham-treatment). A fifth group received no treatment (control). Deaths were registered every 12 h for 8 consecutive days. 3. The results show an increased survival in the group receiving the surfactant-tobramycin mixture compared to the group receiving tobramycin alone (P < 0.05), the group receiving surfactant alone (P < 0.01) and the control groups (P < 0.01). It is concluded that intratracheal instillation of surfactant-tobramycin is superior to tobramycin alone in protecting animals from death due to a respiratory Klebsiella pneumoniae infection.

1. It has been proposed to use exogenous pulmonary surfactant as a drug delivery system for antibiotics to the alveolar compartment of the lung. Little, however, is known about interactions between pulmonary surfactant and antimicrobial agents. This study investigated the activity of a bovine pulmonary surfactant after mixture with amphotericin B, amoxicillin, ceftazidime, pentamidine or tobramycin. 2. Surfactant (1 mg ml-1 in vitro and 40 mg ml-1 in vivo) was mixed with 0.375 mg ml-1 amphotericin B, 50 mg ml-1 amoxicillin, 37.5 mg ml-1 ceftazidime, 1 mg ml-1 pentamidine and 2.5 mg ml-1 tobramycin. Minimal surface tension of 50 microliters of the mixtures was measured in vitro by use of the Wilhelmy balance. In vivo surfactant activity was evaluated by its capacity to restore gas exchange in an established rat model for surfactant deficiency. 3. Surfactant deficiency was induced in ventilated rats by repeated lavage of the lung with warm saline until PaO2 dropped below 80 cmH2O with 100% inspired oxygen at standard ventilation settings. Subsequently an antibiotic-surfactant mixture, saline, air, or surfactant alone was instilled intratracheally (4 ml kg-1 volume, n = 6 per treatment) and blood gas values were measured 5, 30, 60, 90 and 120 min after instillation. 4. The results showed that minimal surface tensions of the mixtures were comparable to that of surfactant alone. In vivo PaO2 levels in the animals receiving ceftazidime-surfactant or pentamidine-surfactant were unchanged when compared to the surfactant group. PaO2 levels in animals receiving amphotericin B-surfactant, amoxicillin-surfactant or tobramycin-surfactant were significantly decreased compared to the surfactant group. For tobramycin it was further found that PaO2 levels were not affected when 0.2 M NaHCO3 (pH = 8.3) buffer was used for suspending surfactant instead of saline. 5. It is concluded that some antibiotics affect the in vivo activity of a bovine pulmonary surfactant. Therefore, before using surfactant-antibiotic mixtures in clinical trials, interactions between the two agents should be carefully evaluated.

To predict at an early phase the clinical course and outcome of nosocomial Staphylococcus aureus bacteremia, the APACHE II score at onset of bacteremia was calculated in 99 patients. A delta APACHE II score (i.e., the difference between this score and one calculated for the day before the bacteremia) was also determined. This delta APACHE II score was highly significantly correlated with clinical course (P<.001) and outcome (P<.001). The risk of a complicated clinical course and of dying from S. aureus bacteremia is determined at the very onset of bacteremia, and this risk can best be assessed by calculating the delta APACHE II score. Furthermore, a positive correlation was found between delta APACHE II scores and the level of serum opsonic activity (P=.003) toward S. aureus. Therefore, the complicated clinical course of S. aureus bacteremia is not due to a relative lack of specific opsonins.

In studying the anti-mannan antibodies longitudinally in serial serum samples of three immunocompromised patients, it was observed that anti-mannan antibodies started to increase shortly after the moment that cultures of deep-tissue sites became positive with Candida albicans. The mean anti-mannan antibody titers determined in a group of 36 immunocompromised patients with invasive candidiasis increased within two weeks after the probable onset of invasive candidiasis. In contrast, anti-mannan antibody levels in serial serum samples of 14 immunocompromised patients who were only colonized with C. albicans remained stable or decreased over time. The HA test measuring the anti-mannan antibodies was 64% sensitive and 89% specific in determining invasive candidiasis. In contrast, antibodies specific for candidal cytoplasmic antigens or enolase alone were of little value in confirming invasive candidiasis in these immunocompromised patients.

Meropenem is a recently developed carbapenem antibiotic, similar to imipenem, with a wide spectrum of activity against Gram-positive and Gram-negative bacteria. In comparison with imipenem, meropenem is relatively stable to hydrolysis by the enzyme dehydropeptidase I (DHP-I), thus precluding the need for coadministration with an inhibitor of DHP-I, such as cilastatin. Furthermore, meropenem may be less nephrotoxic and neurotoxic than imipenem. Plasma meropenem concentrations reach a peak (Cmax) of approximately 30 mg/L after administration of a standard dose of 1 g intravenously. The elimination half-life (t1/2) is approximately 1 hour, and the area under the plasma concentration-time curve increases linearly in a dose-related manner. The volume of distribution is 21L, indicating predominantly extracellular distribution. Meropenem distributes partly into cerebrospinal fluid. The drug is eliminated both by metabolism and excretion. In normal volunteers, up to 70% is recovered in urine, and the remainder is accounted for by a beta-lactam ring-opened form of the compound, ICI 213689. The t1/2 of meropenem is prolonged in patients with renal insufficiency and correlates well with creatinine clearance. Dosage adjustments in people with decreased creatinine clearance can, thus, be made on the basis of creatinine clearance.

To evaluate the importance of nasal carriage of Staphylococcus aureus as a risk factor for the development of wound infection at the sternotomy site after cardiac surgery, a case-control study was done. The study population consisted of 1980 consecutive patients. Cases were all patients who developed a sternal wound infection from which S. aureus was cultured. Forty cases were identified, and 120 controls were selected. Preoperative nasal carriage of S. aureus, insulin-dependent diabetes mellitus, and younger age were identified as significant risk factors. The crude odds ratio of nasal carriage was 9.6 (95% confidence interval, 3.9-23.7). The median postoperative length of hospital stay for cases was 30 days longer than for controls. Mortality was also significantly higher for cases than for controls (10.0% and 0.8%, respectively).

Postoperative infections (PIs) are serious complications of thoracic surgery. To gain insight into the nature and the scope of the problem, an 18-month prospective surveillance was conducted at the department of thoracic surgery of the University Hospital Rotterdam, Dijkzigt. PI were classified according to CDC criteria. One hundred and ninety-four out of 983 patients (19.7%) developed one or more PIs and in these 194 patients, 268 PIs were diagnosed. The incidence of PI was 2.0 per 100 days of postoperative stay. The mean postoperative length of stay (LOS) of the 194 patients with PI was 14.1 days longer than those without PI. Deep surgical wound infections (DSWIs) were associated with the longest prolongation of the median postoperative LOS in the hospital (30 days longer). Although lower than DSWIs, incisional surgical wound infections also had a significant prolongation of stay (median 10 days longer). Staphylococcus aureus was the most important pathogen associated with surgical wound infections (SWIs). Phage typing of 29 strains causing SWI showed only two identical pairs, so only a minority of infections could be explained by cross-infection. Older age, and more complicated procedures (e.g. cardiac valve operations) were independent, statistically significant, risk factors for the development of PI. Since there is a progressive trend towards operating on older patients and performing more complicated procedures, the incidence of PI is expected to increase. Therefore it will become increasingly important to develop new strategies to prevent these serious complications.

The Clearview Chlamydia test (CV; Unipath Ltd., Bedford, United Kingdom), the Magic Lite Chlamydia test (ML; CIBA Corning, Medfield, Mass.), a polymerase chain reaction (PCR), and cell culture (CC) were evaluated for detection of Chlamydia trachomatis in urogenital specimens. Specimens were collected from 283 men and 724 women visiting the outpatient clinic for Sexually Transmitted Diseases at the University Hospital Rotterdam, Rotterdam, The Netherlands. ML, PCR, and CC were all performed on the same sample to prevent swab-to-swab variability. CV was performed on a separate sample. Analysis of discordant results was performed by application of the following confirmatory assays: first, PCR on the CC, second, ML was repeated, and third, PCR was repeated by using a different DNA extraction protocol. If more than one test was positive, the sample was considered true positive. If only one test was positive, which was confirmed by the confirmatory assay, the sample was also considered true positive. By using these interpretations, the following results were obtained. The sensitivity and specificity of CV for samples from men were 60.4 and 86.3%, respectively. For samples from women, these values were 62.3 and 99.7%, respectively. The low specificity for samples from men was caused by unidentified substances in the swab that was used. The use of CV on samples from men is not recommended by the manufacturer. For samples from women, the specificity of CV was high, but the low sensitivity of CV limits its use for diagnostic purposes. The sensitivities of ML were low for samples from both men and women (68.8% and 50.9% respectively), while specificities were excellent for samples from both groups (100 and 99.9%, respectively). The low sensitivity of ML limits its diagnostic value. The PCR technique was highly specific for samples from both men (99.6%) and women (99.9%). The sensitivity of PCR, however, was unexpectedly low for samples from both groups (men, 87.5%; women, 79.2%), most likely because of the sample treatment method used. The sensitivity and specificity values of CC for samples from men were 95.8 and 100%, respectively. For samples from women, these values were 100 and 99.9%, respectively. In the present study, CC was the most reliable technique for the detection of C. trachomatis.

Objective: To study the feasibility and applicability of Home intravenous antibiotic treatment (HIVAT) in cystic fibrosis (CF) patients in the Netherlands., Design: Prospective, multicentre study in CF patients with an exacerbation of a Pseudomonas aeruginosa pulmonary infection using a computerised, ambulatory pump for continuous infusion., Method: The effects of HIVAT were studied during one year in 24 CF patients (9 male, 15 female; mean age 23.3 years, range 7-52), who received a total of 39 courses of continuous ceftazidime 100 mg/kg/24 hrs i.v. for 3 weeks delivered by a pump. The treatment was preceded by a 2-3 days in-hospital instruction period. The treatment was supervised by the clinic without home visits. Clinical data and quality of life questionnaires were collected at the start and at the end of treatment and one month later. Statistical analysis was performed using Wilcoxon's rank-sum test for paired samples., Results: No major problems were encountered. The patients as well as their physicians preferred home treatment over in-hospital treatment. 35 out of 37 evaluable courses in 23 patients were efficacious. There were statistically significant improvements in clinical condition and quality of life during the treatment. This improvement lasted at least until one month after the end of treatment. The costs of HIVAT were 48-63% less than the same antibiotic treatment in the hospital., Conclusion: HIVAT was feasible and could be applied without major problems in the Netherlands. It proved safe, efficacious and cost-effective.

Objective: The optimal dose and frequency of GH administration in Turner's syndrome is unknown. There is some evidence that a schedule which mimics normal pulsatile GH secretion may be more effective than a single daily dose. We therefore wished to study the influence of the frequency of GH administration on 24-hour GH profiles and levels of other growth-related factors in Turner's syndrome., Design: Four weeks after initiation of 0.05 microgram/kg/day ethinyl oestradiol, we compared twice daily (b.i.d.-fractionated dose) with once daily (o.d.) s.c. injections of 6 IU GH/m2/day in a 2-week cross-over design with a 2-week washout interval. Each treatment period was concluded with 24-hour GH profile tests. Pretreatment plasma/serum levels of GH, IGF-I, binding proteins for GH (GHBP) and IGF-I (IGFBP-3) were used as a basis for comparison of the levels found after each regimen. A one-compartment open model was used for estimation of pharmacokinetic parameters., Subjects: Ten previously untreated girls with Turner's syndrome aged > or = 11 years., Measurements: Plasma levels of GHBP by standardized binding assay; GH, IGF-I, and IGFBP-3 serum/plasma levels by radioimmunoassay., Results: There were significantly higher maximum GH levels and a greater area under the curve with o.d. than with b.i.d. GH, while GH clearance was greater with b.i.d. The pharmacokinetic values with o.d. injections were in conformity with values for healthy and GH-deficient children. Pretreatment GHBP levels tended to be high compared with values in healthy prepubertal children. These levels decreased with GH therapy, significantly so with b.i.d. GH only. There was a significant increase in levels of IGF-I and IGFBP-3, irrespective of regimen. The IGF-I to IGFBP-3 ratio, a possible indicator of the growth response, rose significantly and comparably with both regimens. There was no consistent diurnal variation with either regimen in GHBP, IGF-I or IGFBP-3 levels. Four-hourly levels of GH, GHBP, IGF-I and IGFBP-3 were not correlated., Conclusions: Although the 24-hour profiles differed during once or twice daily administration of the same total growth hormone dose, the diurnal pattern and mean levels of factors involved in the biological effects of GH are comparable for both regimens.

Studies of two types of small liposomes, differing with respect to their lipid composition in terms of bilayer fluidity, charge, and hydrophilicity of the liposomal surface, were done to evaluate their usefulness for delivery of encapsulated therapeutic agents to sites of infection. The liposomes showed substantial localization in infected lung tissue after intravenous administration. This was demonstrated in a model of unilateral Klebsiella pneumoniae pneumonia in rats, in which the left lung was infected but the right lung of the same animal developed no infection. The degree of localization in the infected left lung was different for the two types of liposomes. For the liposome type with the longer blood residence time, containing a surface coating of polyethylene glycol, localization in the infected left lung was dependent on the liposomal dose, correlated with the intensity of infection, and reached 9% of the injected liposomal dose in severely infected rats.

Because the surfactant system probably is involved in the pathophysiology of respiratory failure caused by hydrochloric acid (HCl) aspiration, we investigated the effects of different ventilation strategies and intratracheal surfactant instillation at different time intervals on the course of pulmonary gas exchange after HCl aspiration in rats. In this study rats were anesthetized and mechanically ventilated via a tracheostomy. Respiratory failure was induced by intratracheal instillation of 3 mL/kg 0.1 N HCl. Animals (n = 49) were divided into nine groups: Groups 1 and 2 through 9 were ventilated with peak airway pressure/positive end-expiratory pressure of 14/2 and 26/6 cm H2O, respectively; Groups 3 and 4 received surfactant (200 mg/kg) intratracheally, 1 and 10 min after HCl aspiration; Groups 5 and 6 received saline, 1 and 10 min after HCl aspiration; Groups 7 and 8 received surfactant, 60 and 90 min after HCl aspiration; Group 9 received saline instead of HCl. Gas exchange deteriorated in Groups 1, 2, 5, 6, 7, and 8, whereas respiratory failure could be prevented in Groups 3 and 4. After deterioration of gas exchange, surfactant treatment prevented further decrease of PaO2 values in Group 7, whereas no effect on gas exchange was observed in Group 8; intratracheal instillation of saline had no effect on gas exchange (Group 9). These results suggest that surfactant should be given as early as possible after aspiration of gastric contents to prevent development of respiratory failure.

Optimal use of a drug depends on rational dosing and subsequent therapeutic drug monitoring for effectiveness and toxicity. Drug monitoring is not relevant for all drugs, but is indicated in the case of drugs which have a narrow therapeutic range or show a large inter-individual variation. If the response is not satisfactory or toxic side effects are observed, the regimen has to be adjusted or another drug used. Methods have been developed to establish rational dosing schedules for the individual patient. In previous methods, the patient's specific data such as age, length, weight and serum creatinine are integrated with population pharmacokinetic parameters for a drug. This approach is subject to an appreciable margin of error, particularly in patients whose physiology is far from normal. Therapeutic drug monitoring via blood level determination makes it possible to evaluate the patient's individual pharmacokinetic parameters on which a rational dosage regimen can be based.

We recently demonstrated that oral immunization with a polyvalent bacterial lysate (Paspat oral) significantly reduces mortality rates in mice, infected with Streptococcus pneumoniae or influenza A virus. In this study it is demonstrated that oral immunization with the same bacterial lysate reduces the intrapulmonary inflammatory reaction to infection with S. pneumoniae, assessed by measurement of PMN elastase in bronchoalveolar lavage fluid. Furthermore, it is demonstrated that oral immunization with Paspat oral increases intrapulmonary IFN-gamma concentrations.

The Gen-Probe PACE 2 assay (GP), a nonisotopic DNA probe, was evaluated by using cell culture as the method of reference. Specimens were collected from 260 men and 482 women visiting the outpatient department for sexually transmitted diseases at the University Hospital in Rotterdam, The Netherlands. The prevalences of Chlamydia culture-positive men and women were 13.2 and 8.6%, respectively. Sensitivity values for the male and female patients were 70.6 and 92.7%, respectively. Specificity values for these groups were 98.2 and 97.7%, respectively. Sensitivity was significantly lower when the number of inclusions in cell culture was low. Samples which showed a discordance between cell culture and GP results were retested by the polymerase chain reaction. If the results of the polymerase chain reaction were considered as the points of reference, the sensitivity and specificity of both GP and cell culture could be calculated. The performance of GP for females was comparable to that of cell culture. In males, the sensitivity of GP was considerably lower than that of cell culture (77.2 versus 91.4%), while specificity was somewhat higher (99.6 versus 99.1%). Compared with cell culture, the GP is a relatively simple and rapid test that is suitable for diagnosing Chlamydia infections in urogenital specimens.

A study is presented which investigated whether oral immunization with a polyvalent bacterial lysate (Paspat oral) can sufficiently enhance cell-mediated defense mechanisms to protect mice against influenza A virus infection. It was found that oral immunization reduced mortality due to influenza A infection with 15-70%, depending on the quantity of virus administered and and the moment of infection. Cyclosporin A severely reduced the protective effect of oral immunization, suggesting that a major effect of oral immunization in these studies is T-cell activation. The effect of oral immunization on macrophageal activity was evaluated by measuring cyclic-AMP in alveolar macrophages (AMs) obtained by bronchoalveolar lavage. Before infection, basal activity levels of AMs in immunized mice were significantly lower than in controls. Five days after infection, however, basal activity level of AMs in immunized mice was significantly higher than AM activity in controls. Stimulation of AMs with PGE2 significantly reduced cellular activity in both groups, before and after infection. However, cellular activity of AMs from immunized animals was less reduced than cellular activity of control macrophages. Activity of AMs of immunized animals was significantly more reduced by histamine than activity of control macrophages. It is concluded that oral immunization with Paspat oral stimulates T-cell-dependent immune mechanisms, resulting in protection against influenza A virus infection in mice.

We investigated the effect of oral immunization in of mice which were exposed to S. pneumoniae or influenza A. The results suggest that oral immunization reduces the mortality rate. We believe that this effect is partially due to nonspecific defense mechanisms.

Bacterial lung infections determine the prognosis for most cystic fibrosis patients. The antibacterial therapy is difficult because of the host-bacterium interaction and altered pharmacokinetics. The new insights in the working mechanisms of antibiotics that may lead to better treatment results have been discussed, and guidelines for treatment of lung infections in cystic fibrosis patients were given.

The protective effect of oral immunization against infection with Streptococcus pneumoniae was investigated in mice. Two bacterial lysates, one with an additional lysate of Candida albicans, were investigated. Intranasal inoculation of adult Balb-C mice with a S. pneumoniae type I strain resulted in a lethal infection, with deaths occurring from the 2nd until the 6th day after infection. Oral immunization resulted in a significant decrease in mortality rate (18-48% reduction). No significant difference in mortality rates was observed between the groups immunized with different lysates in the same concentrations.