[Serodiagnosis of Legionella pneumonia--data of our laboratory in the recent 3 years].

We had examined antibody titers against Legionella spp. of patients' sera which were mainly sent from other hospitals, performed with the indirect fluorescent antibody (IFA) method. The clinical status of the cases diagnosed as Legionella pneumonia serologically, were also studied. Out of 105 cases with clinically suspected Legionella pneumonia, 15 cases (14.3%) were seropositive. In 9 out of the 15 cases (60.0%) were caused by Legionella pneumophila serogroup 1. Clinical outline of these 15 cases did not contradict those reported in the literature, and erythromycin was effective in many cases. Significant rises (more than four times) of the titer were observed 3 to 4 weeks after onset in most of cases. We would like to emphasize that this should be performed serodiagnosis of Legionella pneumonia.

[A case report of miliary tuberculosis with acute respiratory failure diagnosed by polymerase chain reaction method].

A 51-year-old male was admitted because of cough and high fever. His chest X-ray and CT revealed miliary shadows, he was administered some antibiotics. But on the 8th day, his chest X-ray revealed ground glass shadows and he was under severe hypoxemia. We suspected miliary tuberculosis with acute respiratory failure due to his clinical course. The intensive therapy with antituberculosis drugs, hydrocortisone (1 g/day) was started and intubation was performed. The smear of the clinical samples did not show acid-fast bacilli on admission. However, by the polymerase chain reaction amplification method specific DNA fragments of Mycobacterium tuberculosis complex were detected from BALF and bone marrow. He was extubated after the 13th day and he recovered. It is difficult to separate and identify tubercle bacilli rapidly, but PCR is available for early diagnosis.

[Usefulness of polymerase chain reaction method in the early diagnosis of Pneumocystis carinii pneumonia].

We evaluated the sensitivity and specificity of polymerase chain reaction (PCR) method in the detection of Pneumocystis carinii, and compared its clinical usefulness with that of a previous method, toluidine blue-O (TBO) staining in diagnosis of P. carinii pneumonia (PCP) using clinical samples such as sputum and bronchoalveolar lavage fluid (BALF). Using P. carinii obtained from BALF of the infected rats, we showed that PCR showed 100 fold more sensitivity than TBO staining as indicated by the comparison of their detection limits (78 cysts/ml vs 7800 cysts/ml). In addition, the detection using PCR in this study was specific for P. carinii because all other pathogens examined were not positive. In the clinical study we analyzed 44 patients including 10 with definite PCP, 8 with portable PCP and 26 with other diagnosis. In the sputum, the sensitivity and specificity were 100% and 95%, respectively, in PCR, while 13% and 100% in TBO staining. These results revealed that PCR was much superior to TBO staining in sensitivity especially when the sputum was used as samples, and suggested that examination of the sputum by PCR was clinically very useful in early diagnosis of P. carinii pneumonia.

[Study of Legionella pneumophila detection by two step polymerase chain reaction].

We studied the usefulness of two sets of primers in macrophage infectivity potentiator gene sequence of Legionella pneumophila. PCR by 1st step primers produced 649 bp DNA bands and 2nd step primers 489 bp DNA bands. Two step PCR by these primers produced 489 bp DNA bands specific for L. pneumophila. Two step PCR detected 10 fg of pure DNA extracted from L. pneumophila, Philadelphia-1 strain. PCR sensitivity by these primers was superior to former primers reported by us using intratracheal aspirates collected from the patient with L. pneumophila serogroup 2 pneumonia.

[An animal model of Pneumocystis carinii pneumonia and therapeutic efficacy of interferon-gamma in this model].

To evaluate the efficacy of drugs for treatment, we tried to make an animal model of Pneumocystis carinii (P. carinii) pneumonia. Specific pathogen free (SPF) rats immunosuppressed with corticosteroid were intratracheally inoculated with P. carinii. Six weeks after the inoculation, the lung sections of infected rat lung showed increased numbers of P. carinii in the alveoli and thickening of alveolar septa with mononuclear cell infiltration. From 7 to 9 weeks after inoculation, the intensity of infection became more severe, and some rats died at this period. Then, to evaluate drug efficacy in this model, we finished the drug therapy by the 6th week and used the number of P. carinii in the lung and the inflammation score as an indicator of drug efficacy. In this P. carinii pneumonia animal model, both sulfamethoxazole-trimethoprim clinically established anti P. carinii drug and interferon-gamma which is one of the lymphokines mainly produced by T lymphocytes indicated therapeutic and synergistic efficacy against P. carinii pneumonia.

Influence of methylprednisolone on the intracellular antimicrobial activity of erythromycin and clindamycin against Legionella pneumophila.

We have investigated the effect of methylprednisolone on the intracellular activity of erythromycin and clindamycin in vitro. An assay system was developed for the determination of intracellular activity of antibiotics against Legionella pneumophila using guinea pig resident alveolar macrophages. Erythromycin at a concentration of 0.625 mg/L (5 x MIC) and clindamycin at a concentration of 8 mg/L (MIC) inhibited the growth of a single strain of L. pneumophila in macrophages, whilst ceftizoxime at a concentration of 0.625 mg/L (5 x MIC) did not. Methylprednisolone at therapeutic concentrations did not affect the intracellular antibacterial activity of either erythromycin or clindamycin against L. pneumophila. We found no direct effect of methylprednisolone on the intracellular antibacterial activity of either erythromycin or clindamycin.

[Bacteriological and clinical studies in 23 cases of thoracic empyema--the role of oral streptococci and anaerobes].

The bacteriology of empyema fluid and the clinical background of 23 cases from July 1987 through July 1992 were studied. Nineteen cases were male and 4 female, with a mean age of 59.6 years (range; 33 to 84 y.o.). There were 15 cases of community-acquired infection and 8 of nosocomial infection. Acute pneumonia and/or lung abscess developed into empyema in 19 cases. Sixteen cases had associated predisposing conditions, such as diabetes, chronic bronchitis, disorders with dysphagia, and excess alcohol intake. Forty-one strains were isolated from empyema in 22 cases. The predominant organisms, in order of prevalence, were "Streptococcus milleri" group (11 strains), Peptostreptococcus spp. (6), Prevotella spp. (6), Fusobacterium spp. (5) and other viridans streptococci (3). The majority of streptococcal infections, which were primarily caused by "S. milleri" group, were mixed with anaerobes and/or aerobes/facultatives. These results demonstrate that oral streptococci, especially "S. milleri" group, and anaerobes play a significant role as pathogens in empyema.