Qualitative and quantitative microbiological analysis of sputa of 102 patients with cystic fibrosis.

A microbiological analysis of 102 patients suffering from cystic fibrosis was conducted over a 22 month period. 20 microbial species with the following incidence were identified: Pseudomonas aeruginosa: 83.4%; Candida albicans: 29.4%; Staphylococcus aureus: 24.5%; Staphylococcus epidermidis: 11.8%; Haemophilus influenzae: 11.8%; Streptococcus pneumoniae; 6.9%; Pseudomonas maltophilia: 6.8%; Aspergillus fumigatus: 5.9%. Other species were present in less than 5% of the patients. In the majority of specimens with P. aeruginosa, more than one type (up to six) was detectable. These strains were identical in colony appearance, O-serotype and pyocin-type. Quantitative analysis revealed concentrations of colony-forming units of 10(7) to 10(9) for P. aeruginosa, 10(6) to 10(8) for P. maltophilia, 10(4) to 10(7) for S. aureus, 10(4) to 10(6) for S. epidermidis and 10(4) to 10(7) for C. albicans in the majority of specimens. Significant differences were observed in the time periods during which the pathogens persisted in the patients. Maximum persistence was observed for P. aeruginosa. P. maltophilia and A. fumigatus had about similar persistence rates, which were lower than those for P. aeruginosa but above those for S. aureus and H. influenzae. S. epidermidis was eliminated within shorter periods than S. aureus. C. albicans, although the second most frequent microorganism identified, showed a very low persistence rate. The microbiological analysis confirms results from other research centers (high incidence of P. aeruginosa), but reveals significant regional differences as well (Pseudomonas cepacia not detectable, higher incidence of P. maltophilia and C. albicans). This underlines the necessity for detailed qualitative and quantitative microbiological analysis of sputa from cystic fibrosis patients as a prerequisite for rational analysis of etiological, epidemiological and therapeutical aspects of cystic fibrosis.

[Dependence of the bactericidal activity and mutant selection of 4-quinolones on their serum concentration levels]. / Abhängigkeit von Bakterizidie und Mutantenselektion bei 4-Chinolonen von deren Serumkonzentrationsverläufen.

In an in vitro system, bacterial cultures were exposed to concentrations following the kinetics of 4-quinolones in human serum. Both killing kinetics of staphylococci and enterococci and selection of resistant mutants were shown to be influenced by the pharmacokinetik parameters of the individual substances.

Typing of Enterobacter spp. by bacteriocin susceptibility and its use in epidemiological analysis.

Most clinical isolates of Enterobacter cloacae are bacteriocinogenic and susceptible to bacteriocins. Both rapidly diffusing, nonsedimentable, protease-susceptible and slowly diffusing, sedimentable, protease-resistant bacteriocins are produced. A practicable system was devised for epidemiological typing of E. cloacae isolates by their patterns of susceptibility to bacteriocins. A set of eight bacteriocin-producing strains was grown on tryptic soy agar plates for 16 h. After removal of the producer lawn, the isolates to be typed were inoculated on the agar media by a multipoint inoculator. After a second 16-h period of incubation, the strains were classified into bacteriocin types according to the patterns of growth inhibition. Typability of 134 clinical isolates was 96.3%. Only 11 (8.2%) of the isolates fell into the largest group. Repeat testing of isolates from the same patients within 2 months gave identical bacteriocin types. Other species of Enterobacter (E. agglomerans and E. aerogenes) are also typable by this method.

In vitro activity of ciprofloxacin, norfloxacin and nalidixic acid.

The in vitro antibacterial activity of the new quinoline derivative ciprofloxacin (BAY 0 9867) was evaluated in comparison to norfloxacin and nalidixic acid using 495 clinical strains of gram-negative and gram-positive bacteria. The compound was highly active against Enterobacteriaceae, with MICs ranging from 0.008 mg/l to 4 mg/l, whereas the MICs of norfloxacin ranged from 0.03 mg/l to 16 mg/l. All strains of Pseudomonas aeruginosa and Acinetobacter calcoaceticus were inhibited with a concentration of 2 mg/l ciprofloxacin and 32 mg/l norfloxacin. Ciprofloxacin was also active against gram-positive cocci. The MICs for Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus faecalis ranged from 0.008 to 2.0 mg/l. The activity of ciprofloxacin was only slightly influenced by inoculum size, whereas an acid environment caused a noticeable decrease in the activity. Ciprofloxacin would seem to be a promising antibacterial agent for the treatment of urinary tract infection.

Inactivation of cephalosporins by beta-lactamases of gram-negative rods.

Intracellular beta-lactamase activity of gram-negative rods (four Pseudomonas aeruginosa strains, one strain each of Enterobacter cloacae, Proteus rettgeri, Providencia stuartii and Serratia marcescens) was greatly increased by subinhibitory concentrations of cefoxitin, with the exception of one P. aeruginosa strain. Cefotaxime, cefoperazone and ceftazidime were much less effective as enzyme inducers in these strains. A reduction in beta-lactamase activity after pre-incubation with cephalosporins was observed for particular strains and substances. Susceptibility to beta-lactamases decreased in the following sequence: cephalothin, cefoperazone, cefotaxime, ceftazidime, cefoxitin. There was a good correlation between the degradation of cephalosporins in uninduced cells of Enterobacteriaceae and the minimal inhibitory concentrations except for cefoxitin.

In vitro activity of teichomycin A 2 in comparison with penicillin and vancomycin against gram-positive cocci.

Teichomycin A2, a glycopeptide antibiotic from Actinoplanes teichomyceticus, was tested for its in vitro activity against 190 gram-positive cocci under variable test conditions. Minimum inhibitory concentrations were fairly insensitive to both changes of inoculum size and pH, but were higher on agar than in broth. Teichomycin was about as active as vancomycin against Staphylococcus aureus (both methicillin resistant and sensitive strains), slightly inferior to vancomycin against Staphylococcus epidermidis, and distinctly more active against Streptococcus faecalis.

Simultaneous simulation of the serum profiles of two antibiotics and analysis of the combined effect against a culture of Pseudomonas aeruginosa.

The serum profiles of ceftriaxone (CEF) and netilmicin (NET) were produced in a liquid culture of Pseudomonas aeruginosa, and the change in viable count recorded. Synergism was detectable between CEF and NET despite of the widely disparate serum halflife times of NET and CEF.

Bacteriocins as tools in analysis of nosocomial Klebsiella pneumoniae infections.

Epidemiological analysis of isolates from nosocomial infections caused by Klebsiella pneumoniae was improved by the use of bacteriocins in addition to capsular serotyping. Screening for bacteriocins produced by 77 reference strains for capsular serotyping identified 39 strains, and 8 of these strains were selected as a typing set. Using this set, we found that 241 to 259 (91%) nonepidemic clinical isolates of K. pneumoniae were inhibited by one or more of the eight producers. Of the most frequent bacteriocin type there were 31 examples (12%). High reproducibility of typing patterns (83.3%) and easy practicability of typing were achieved with a streak-and-point method avoiding the use of suspensions of bacteriocins and the risk of instability. The Klebsiella bacteriocins were active also on Enterobacter and Shigella species and on Escherichia coli strains, but were ineffective on other Enterobacteriacae.

[Current chemotherapy of infections caused by Pseudomonas aeruginosa (author's transl)]. / Zur aktuellen Chemotherapie von Infektionen mit Pseudomonas aeruginosa.

In addition to carbenicillin, the newer beta-lactam antibiotics such as ticarcillin and azlocillin are now available for the chemotherapy of Pseudomonas aeruginosa infections. We investigated the in vitro effect of these antibiotics on 233 isolates from clinical material. We were particularly careful, when choosing the experimental material, to exclude copies of the same individual strain, and we achieved this by combining various epidemiological typing procedures. A comparison of carbenicillin, ticarcillin and azlocillin according to the concentrations at which half of the 233 strains were inhibited showed the ticarcillin values to be higher than those of azlocillin by a factor of 2.1, and carbenicillin values to be higher than those of azlocillin by a factor of 4.9. Individual strains also occurred in which the inhibitory concentration for azlocillin was higher than that of carbenicillin (5 strains) or ticarcillin (11 strains). In 17 out of the 233 isolates no therapeutic success would have been within reach even with the newer beta-lactam antibiotics. The use of ticarcillin and azlocillin permits an extension of the indications for therapy with beta-lactam antibiotics in P. aeruginosa infections, from hitherto 76%, to 90% of the cases. If one includes the aminoglycosides gentamycin, tobramycin, sisomycin and amikacin in the therapeutic armoury, then the proportion of in vitro sensitive strains of P. aeruginosa in the material submitted for examination rises to 98%.

[Modified procedure for pyocin typing of Pseudomonas aeruginosa (author's transl)]. / Modifiziertes Verfahren zur Pyocintypisierung von Pseudomonas aeurginosa.

The Procedure for pyocin typing of Pseudomonas aeruginosa isolations as proposed by GILLIES and GOVAN has been modified in the following aspects: strains are arranged in a symmetrical way, with a central producer zone and radial indicator streaks, optimal size of inocula for both producer (300 x 10(6)/ml) and indicators (50 X 10(6)/ml) was determined, unsupplemented Tryptic Soy Agar is used giving identical results to those when TSA is supplemented with 5% horse blood. The typing results obtained with this simplified and standardized procedure were identical with those from the cross streak method.

[The limits of tetracycline treatment in infections of the vagina (author's transl)]. / Grenzen der Tetrazyklintherapie bei Infektionen des Vaginalbereiches.

The minimal inhibition concentration of Tetracycline was tested in 177 strains of gram positive and gram negative species of bacteria from the vagina which were found to be resistant to Tetracycline in the Agardiffusion Test. 170 of the 177 strains (96%) were inhibited with a Tetracycline concentration of 512 microgram/ml. Six Klebsiella-enterobacter strains and one proteus morgaini strain needed a minimal inhibition concentration of 1024 microgram/ml. For a successful local treatment of vaginitis by Tetracycline against species highly resistant to Tetracycline local Tetracycline levels of 1000 microgram/ml or better have to be obtained. Concomitant preventive treatment of fungi for instance, with amphotericin containing drugs such as mysteclin is indicated.