Inhibitory effect of clindamycin on production of beta-lactamase in beta-lactam-resistant bacteria.

The inhibitory effect of clindamycin on beta-lactamase biosynthesis was investigated in beta-lactam resistant bacteria with inducible and/or constitutive production of the enzyme(s). Clinical isolates of Enterobacter cloacae (E. cloacae) and Pseudomonas aeruginosa (P. aeruginosa) were examined. Three strains of each, against which sulbactam at 8 micrograms/ml reduced the minimum inhibitory concentration (MIC) of cefoperazone (CPZ) at least 4 fold, were studied in greater detail. Although clindamycin had no appreciable effect on bacteria growth at concentrations up to 50 micrograms/ml, it suppressed inducible beta-lactamase biosynthesis almost completely at a concentration of 20 micrograms/ml. There was also a significant reduction of constitutive enzyme biosynthesis by clindamycin at 50 micrograms/ml. Thus, it was estimated that a high concentration of clindamycin was required to suppress beta-lactamase biosynthesis in beta-lactamase producing bacteria of the constitutive type.

[Culture-positive Legionella pneumonia in Japan, 1980-1990. Working Party for Legionellosis, Japanese Ministry of Health and Welfare].

The Working Party for Legionellosis headed by the Japanese Ministry of Health and Welfare processed to standardize the diagnostic procedures for Legionella pneumonia, as the first step to clarify the actual occurrence of patients with this respiratory disease. All the clinical data were collected and analysed on the 28 culture-confirmed patients in Japan during the past 11 years, from 1980 through 1990. The 28 patients were distributed throughout Japan, from Hokkaido to Kyushu. Out of 28 patients, 18 were community-acquired and 10 were nosocomially infected. In 8 of 18 community-acquired patients, any significant underlying disease was not observed. Though it was dominant in the age group in their 60s & 70s, victims were distributed in adults over 20 years of age and even in a new born baby. Only 5 out of 28 patients recovered successfully. From the autopsy findings, in 5 out of the remaining 23 expired patients, Legionella pneumonia seemed to be successfully treated, but other disease or other bacterial pneumonia put an end to the patients. The results of clinical laboratory tests and the efficacy of antibiotics to Legionella pneumonia were essentially the same as those reported in the literature.

[Analysis of chest radiographs of culture positive Legionella pneumonia in Japan, 1980-1990. Working Party for Legionellosis, Japanese Ministry of Health and Welfare].

We analyzed the initial and follow-up chest radiographs of 28 patients with culture-positive Legionella pneumonia, and developed a scoring system to quantitate the severity of radiological findings for pneumonia. Intrapulmonary shadows were observed on the initial chest radiograph in 26 patients, but pleural effusion was noted in only one. In one patient the initial chest radiograph had probably been obtained too early to reveal any pulmonary change. Alveolar shadows were noted on the initial radiograph in 21 (81%) patients, and interstitial shadows in 5 (19%). In ten (38%) patients shadows were present in both lung fields. Shadows were prominent in the middle and lower lung fields. A cavity was noted in only one patient, and pleural effusion was also noted at some time during the clinical course in 19 (70%). A large amount of pleural effusion was observed in four patients. The average pneumonia severity score was 3.3 in the 9 patients who survived, and 5.1 in the 17 who died (p > 0.05). The mortality rate was 53% in the 17 patients with pneumonia severity score of 5 or less and 89% in the 9 patients with a score of 6 or more (p > 0.05). Twelve patients died within one week after the initial chest radiograph was obtained. There were no differences among patients with community-acquired infection with or without underlying disease and those with nosocomial infection in characteristic and extension of shadow, presence of pleural effusion, or pneumonia score. The chest radiograph of Legionella pneumonia include bilateral shadow findings characteristic, pleural effusion and rapid progression of shadow, and are clinically useful for diagnosis.

Synergistic effects of romurtide and cefmenoxime against experimental Klebsiella pneumonia in mice.

We investigated the synergistic effects of romurtide (MDP-Lys [L18]) and cefmenoxime (CMX) in the treatment of experimental Klebsiella pneumonia in mice. Mice were infected with 1 x 10(4) CFU of Klebsiella pneumoniae by inhalation of aerosol bacterial suspension. About 90% of untreated animals died within a week; however, the mortality rate of animals treated with CMX alone at a dose of 40 mg/kg/day was 60% at 7 days after the infection. When one or two doses of L18 were administered before or after the infection concomitantly with CMX, a remarkable improvement in the survival rate was observed. There was no significant improvement in the survival rate of animals treated with L18 alone before or after infection. Histopathological sections of the lungs of mice treated with CMX and L18 showed slower progression of infection than those of mice treated with CMX alone. Significant differences were also found in quantitative cultures of viable bacteria in the lungs 1 to 4 days after the infection. Although viable bacterial counts in the lungs of the control and CMX-treated groups showed a rapid increase 24 to 48 h after the infection, they remained lower than the initial counts (x 10(4)) in the lungs of mice treated with combination regimens. From these results, it can be concluded that L18 is a useful biological response modifier in the treatment of acute pulmonary bacterial infections.

[Molecular diagnosis in respiratory infections].

Recent advance in molecular biology has enabled the specific and rapid diagnosis of the various infectious diseases. Though we commonly use the three major diagnostic procedure as isolation of the pathogen, direct detection of the pathogen and measurement of the immunological host reaction, DNA probe method would be the fourth major procedure in the clinical microbiology. The indication of the DNA probe method would be considered in the four cases as follows, 1. necessity of the special equipment to isolate the pathogen, 2. necessity of the long period to isolate the pathogen, 3. existence of the cross reaction among the pathogen and relative organisms in the immunological procedure, 4. existence of the difficulty to identify the species of the pathogen by the ordinary procedure. When we consider those indications, Legionnaires' disease might be one of the typical infectious disease to show the benefits of the DNA probe method in diagnosis. So far two types of DNA probe kits for Legionnaires' disease are available. One is the genus specific direct detection kit from the clinical specimens (Gen-probe), and the other is the microplate hybridization kit to identify each species of Legionella. The results of the evaluations of both kits showed the high specificity, rapidity and the clinical usefulness. In the next few years, various types of DNA probe kits might be newly developed and the contribution of those in the clinical microbiology would be much more than we expected.

[A case of pneumonia caused by Chlamydia pneumoniae, strain TWAR].

A case of pneumonia caused by C. pneumoniae, strain TWAR is described in this paper. A 65 year-old male with a persistent dry cough was admitted to our division for left lower lobe infiltrates of the chest X-ray. The serum antibody titers against mycoplasma and some viruses were not elevated, but the serum antibody titers against TWAR reached the maximum level (IgG X 1024, IgA X 256) using microplate immunofluorescence antibody technique (MFA). Isolation of TWAR was tried by BAL and nasophalingial swabs, but were not successful. TBLB from Lt. S10 revealed TWAR inclusion bodies within alveolar epithelial cells using TWAR specific monoclonal antibody (Washington Research Foundation).

[A case of pneumonitis due to sho-saiko-to].

We reported a case of pneumonitis due to Sho-saiko-to. A 71-year-old woman was admitted to our hospital because of pneumonia. She complained of dry cough, pyrexia and severe dyspnea. Fine crepitation was heard on physical examination of the chest and a chest X-ray film revealed diffuse reticulo-nodular shadow in both lung fields. We suspected summer-type hypersensitivity pneumonitis and followed her up, however her condition deteriorated. Under a suspicion of drug-induced pneumonitis, all drugs were stopped and she was given prednisolone. Consequently her complaints, laboratory data and chest X-ray findings markedly improved. Microscopic examination of a transbronchial lung biopsy specimens showed interstitial pneumonitis. The results of a lymphocyte stimulation test were positive for sho-saiko-to. She gave informed consent after receiving an explanation of the challenge test. She was tested with 2.5 g sho-saiko-to twice and developed high fever and dyspnea with hypoxia, while the chest X-ray film also revealed diffuse infiltrative shadows similar that on admission. Based on these findings, we diagnosed this case as pneumonitis due to sho-saiko-to. To our knowledge, there has been no previous case of pulmonary hypersensitivity due to sho-saiko-to reported in the world.

[A case of chronic bronchitis with Pasteurella multocida possibly resulting from infection from a bird].

A 60-year-old woman was admitted to our division for further evaluation of fever and purulent sputa. In sputum cultures performed when the patient had complained of an increase in symptoms on three occasions during the previous 6 months, Pasteurella multicoida was usually detected. Based on the fact that the bacteria had been detected from the patient's sputa after feeding a macaw, but was not detected after treatment of the bird with OFLX, a diagnosis of respiratory tract infection by P. multocida was made. Clinical symptoms and laboratory data of the patient were markedly improved after treatment with cefaclor (750 mg/d). The bacteria in this case were sensitive toward many antibiotics. This case was considered to be the first case of bird-mediated Pasteurella infection.

[Detection of inducible beta-lactamase in sputum--clinical studies on Pseudomonas respiratory infection].

To investigate the clinical incidence of inducible beta-lactamase, we measured the beta-lactamase activity in the sputum of 5 patients with chronic respiratory tract infection due to P. aeruginosa, by using the spectrophotometric method. During the piperacillin (PIPC) therapy given twice a day with a single dose of 2-3 g, sputum samples were collected every 2 hours for 3 days, and on the second day, two grams of Cefmetazole (CMZ) was added to PIPC therapy. The antibiotics concentration of each collected sputum samples were also measured by HPLC. In one out of 5 patients, no beta-lactamase activity in sputum was detected throughout the 3 days. However in three out of 5 patients, after the addition of CMZ to PIPC, the beta-lactamase activity significantly increased 2-3 times (max: 0.03 units/ml) that on PIPC alone, and gradually decreased on the 3rd day when PIPC was given alone. Then the peak concentration of PIPC with the addition of CMZ decreased to 38-73%, compared with that of PIPC alone. These findings were supported by the fact that CMZ showed a high in vitro inducer activity against the isolates from the sputum. In the remaining one patient, high beta-lactamase activity (mean: 0.16 units/ml) and no antibiotics concentration was detected to be constant throughout the 3 days, and it was confirmed for the reason that one of the isolates constitutively produced large amounts of beta-lactamase. These results suggest that inducible and constitutive beta-lactamase would clinically cause undesirable effects in the treatment by some beta-lactams and have a possibility of indirect pathogenesis.

Comparison of blood culture methods for recovery of Legionella pneumophila from the blood of guinea pigs with experimental infection.

Blood was cultured from guinea pigs with experimental Legionella pneumophila serogroup 1 pneumonia, using four different methods. A 0.03-ml amount was spread onto each of several plates of buffered charcoal-yeast extract supplemented with alpha-ketoglutarate (BCYE) (direct plate); 1.5 ml each was inoculated into a BCYE agar-yeast extract broth bottle (biphasic), a pediatric Isolator tube (E. I. du Pont de Nemours & Co., Inc., Wilmington, Del.), and a glass tube containing 0.025% sodium polyanethanolsulfonate. Blood processed in the Isolator tube was plated on BCYE, as was the buffy coat blood fraction, which was obtained by centrifugation of the tube containing sodium polyanethanolsulfonate and blood. Observations were made of the number of positive cultures, the time to detection of positive cultures, and the absolute bacterial concentrations. Each system was equally sensitive in detecting bacteremia. The biphasic method required 5 days for cultures to become positive, whereas the other systems required 2 to 3 days to detect all positive cultures (P = 1.3 X 10(-5) by Friedman group statistic, and P less than 10(-5) for comparison of the biphasic and other methods). The direct plating method demonstrated the best quantitative recovery of L. pneumophila in comparison to the other methods tested (P = 2.0 X 10(-5) by analysis of variance group statistic and P less than 0.05 for comparison between each of the methods). Quantitative recovery by the Isolator method was intermediate between the direct plating and buffy coat methods. The biphasic and Isolator blood culture methods performed poorly in comparison to the other methods, indicating the need for caution in choosing blood culture methods for Legionella isolation.

Paleoepidemiologic investigation of Legionnaires disease at Wadsworth Veterans Administration Hospital by using three typing methods for comparison of legionellae from clinical and environmental sources.

Multilocus enzyme electrophoresis, monoclonal antibody typing for Legionella pneumophila serogroup 1, and plasmid analysis were used to type 89 L. pneumophila strains isolated from nosocomial cases of Legionnaires disease at the Veterans Administration Wadsworth Medical Center (VAWMC) and from the hospital environment. Twelve L. pneumophila clinical isolates, obtained from patients at non-VAWMC hospitals, were also typed by the same methods to determine typing specificity. Seventy-nine percent of 33 VAWMC L. pneumophila serogroup 1 clinical isolates and 70% of 23 environmental isolates were found in only one of the five monoclonal subgroups. Similar clustering was found for the other two typing methods, with excellent correlation between all methods. Enzyme electrophoretic typing divided the isolates into the greatest number of distinct groups, resulting in the identification of 10 different L. pneumophila types and 5 types not belonging to L. pneumophila, which probably constitute an undescribed Legionella species; 7 clinical and 34 environmental VAWMC isolates and 2 non-VAWMC clinical isolates were found to be members of the new species. Twelve different plasmid patterns were found; 95% of VAWMC clinical isolates contained plasmids. Major VAWMC epidemic-bacterial types were common in the hospital potable-water distribution system and cooling towers. Strains of L. pneumophila which persisted after disinfection of contaminated environmental sites were of a different type from the prechlorination strains. All three typing methods were useful in the epidemiologic analysis of the VAWMC outbreak.