Jutta Wagner

Comparison of Broth Microdilution, E Test, and Agar Dilution Methods for Antibiotic Susceptibility Testing of Campylobacter jejuni and Campylobacter coli

ABSTRACT A standardized broth microdilution method was compared to the E test and an agar dilution method for the antimicrobial susceptibility testing of Campylobacter jejuni and C. coli isolates. A group of 47 human clinical isolates, 37 isolates from retail poultry, and 29 isolates from living turkeys (total, 113 isolates) was included in the study. These encompassed 92 C. jejuni and 21 C. coli strains. The MICs of six antimicrobial agents were determined by the broth microdilution and E test methods, and the strains of human origin were additionally tested by the agar dilution method. In general, broth microdilution MICs agreed within 1 log2 MIC increment with 90.0% of E test results and 78.7% of agar dilution test results. The agar dilution method gave much lower gentamicin MICs than the broth microdilution method, but the data were significantly (P < 0.01) correlated and there was 100% agreement in the sensitivities and specificities in the comparison of the tests. The broth microdilution method had the highest sensitivity for analysis of the susceptibilities of Campylobacter to nalidixic acid and trimethoprim-sulfamethoxazole. The MICs of ciprofloxacin and erythromycin complied numerically by all three methods. The classification of the results and the correlation of the data demonstrated a high degree of agreement. All methods were equally suitable for the testing of the sensitivity of Campylobacter to tetracycline. Thus, the broth microdilution method appears to be an easy and reliable method for determination of the MICs of antibiotics for C. jejuni and C. coli, and it may offer an interesting alternative to MIC determination by the agar dilution technique or the E test.

Antimicrobial Resistance in Campylobacter jejuni and Campylobacter coli Strains Isolated in 1991 and 2001-2002 from Poultry and Humans in Berlin, Germany

ABSTRACT The susceptibilities of 430 Campylobacter jejuni strains and 79 C. coli strains to six antimicrobial agents were tested and analyzed. The two sets of strains originated from retail market chicken and turkey samples and from humans, respectively, in Berlin, Germany. Two groups of isolates, one dating from 1991 and the other dating from 2001-2002, were tested. Of the Campylobacter sp. isolates recovered from humans in 2001-2002, 45.1% were resistant to ciprofloxacin, 37.8% were resistant to tetracycline, 12.8% were resistant to ampicillin, and 50.0% were resistant to trimethoprim-sulfamethoxazole. All isolates were susceptible to gentamicin, while the overall rate of resistance to erythromycin was 6.1%. During the 10 years between the two sampling times, the rates of resistance to ciprofloxacin (P< 0.001), ampicillin (P = 0.035), and tetracycline (P = 0.01) increased significantly among strains isolated from humans. Furthermore, among human C. coli strains the rate of resistance to erythromycin rose from 7.1% in 1991 to 29.4% in 2001-2002. In comparison, Campylobacter sp. isolates from poultry already had high rates of resistance in 1991. Different rates of resistance to tetracycline among isolates from chickens and turkeys suggested the development of resistance during antimicrobial treatment in food animals. Thus, discrepancies in the antimicrobial resistance rates among Campylobacter isolates originating from poultry and humans support the hypothesis that at least some of the resistant Campylobacter strains causing infection in humans come from sources other than poultry products.

Prospective randomized controlled study of ciprofloxacin versus imipenem-cilastatin in severe clinical infections.

In a randomized prospective study, 66 patients with serious bacterial infections--mainly lower respiratory tract infections--were treated with either imipenem plus cilastatin (32 patients) or ciprofloxacin (34 patients); 30 patients in each group were evaluable for efficacy. Substantial underlying disease was present in most of the patients; pathogens isolated prior to treatment (77 isolates) consisted mainly of members of the family Enterobacteriaceae, Pseudomonas aeruginosa, Staphylococcus aureus, Haemophilus influenzae, and streptococci. Of the etiologic bacteria, 67% were eradicated by ciprofloxacin treatment and 79% by imipenem therapy; however, two patients (6.7%) failed in the ciprofloxacin group, and six patients (20%) did not respond to imipenem treatment (P = 0.25). All patients with therapeutic failures suffered from severe fatal underlying diseases, which had substantial impact on the outcome of treatment. Therapeutic drug monitoring in the ciprofloxacin patients revealed higher concentrations in serum at days 4 and 8 in comparison with day 1 of treatment, indicating that steady-state conditions were reached between days 1 and 4. The total number of side effects was relatively high--eight imipenem patients (25%) and six ciprofloxacin patients (18%) had reactions. Treatment had to be discontinued due to adverse reactions for three ciprofloxacin patients and two imipenem patients. Major side effects in both groups were gastrointestinal and central nervous system-related symptoms. In terms of clinical and bacteriological efficacy and safety, there was no statistical difference between the two groups, and both groups gave good to excellent results for bacterial infections that were difficult to treat.

Infection of the Skin Caused by Corynebacterium ulcerans and Mimicking Classical Cutaneous Diphtheria

Extrapharyngeal infections caused by Corynebacterium ulcerans have rarely been reported previously, and diphtheria toxin production has usually not been addressed. This case demonstrates that strains of C. ulcerans that produce diphtheria toxin can cause infections of the skin that completely mimic typical cutaneous diphtheria, thereby potentially providing a source of bacteria capable of causing life-threatening diseases in the patients environment. Therefore, it is recommended to screen wound swabs for coryneform bacteria, identify all isolates, carefully assess possible toxin production, and send questionable strains to a specialist or a reference laboratory.

Listeria meningitis: report of ten recent cases and review of current therapeutic recommendations.

Ten cases of meningitis due to Listeria monocytogenes were admitted to three hospitals in Berlin between 1978 and 1983. One patient was a premature infant in whom meningitis was diagnosed as part of typical granulomatosis infantiseptica. Another presented with signs of brainstem encephalitis which was confirmed post mortem. Positive blood cultures were obtained from five of the patients. Two strains of listeria were resistant and one was only moderately sensitive to penicillin. The three most recently isolated strains were tested for sensitivity to the third generation cephalosporins. All were resistant to latamoxef, and two were resistant to cefotaxime. The implications of these findings for the empirical treatment of purulent meningitis are discussed.

Staphylococcus aureus in Atopic Dermatitis and in Nonatopic Dermatitis

ABSTRACT: Skin colonization with Staphylococcus aureus (S. aureus) was examined in 30 patients with atopic dermatitis (AD), in 25 patients with nonatopic eczema (NAE) and in 30 individuals as healthy controls (HC). Bacteria growth was examined in aerobic cultures and the population densities per dish were estimated; S. aureus colonization was found in the eczematous skin of 24 of 30 (80%) AD patients and in 13 of 25 (52%) NAE patients (NS, p > 0.1). In nonaffected skin S. aureus colonization was found in 19 of 30 (63%) of all AD patients compared with 6 of 25 (24%) in NAE patients and 1 of 30 (3%) in HC, respectively (p < 0.05). In nonaffected skin, coagulase negative strains of Staphylococcus were found in 25 of 30 (84%) controls and in 18 of 25 (72%) NAE patients compared with 12 of 30 (40%) patients with AD. It seems that colonization with S. aureus is not a characteristic feature for atopic dermatitis but is a frequent event in damaged skin; significantly elevated values were also observed in nonatopic eczema. The degree of colonization may depend on the severity and duration of the eczematous lesions.

Susceptibilities of Campylobacter jejuni Isolates from Germany to Ciprofloxacin, Moxifloxacin, Erythromycin, Clindamycin, and Tetracycline

ABSTRACT To elucidate Campylobacter jejuni resistance to antibiotics in Germany, MICs of ciprofloxacin, moxifloxacin, erythromycin, clindamycin, and tetracycline were determined (using agar dilution) for 144 clinical isolates. The data indicate a considerable ciprofloxacin resistance (45.1%) without a clonal relationship of the strains and a greater in vitro activity of moxifloxacin, erythromycin, and clindamycin.

Rapid and Accurate Diagnosis of Human Intestinal Spirochetosis by Fluorescence In Situ Hybridization

ABSTRACT Human intestinal spirochetosis (HIS) is associated with overgrowth of the large intestine by spirochetes of the genus Brachyspira. The microbiological diagnosis of HIS is hampered by the fastidious nature and slow growth of Brachyspira spp. In clinical practice, HIS is diagnosed histopathologically, and a significant portion of cases may be missed. Fluorescence in situ hybridization (FISH) is a molecular method that allows the visualization and identification of single bacteria within tissue sections. In this study, we analyzed intestinal biopsy samples from five patients with possible HIS. All specimens yielded positive results by histopathological techniques. PCR amplification and sequencing of the 16S rRNA gene were performed. Sequences of two isolates clustered in the group of Brachyspira aalborgi, whereas in three cases, the sequences were highly similar to that of Brachyspira pilosicoli. Three phylotypes showed mismatches at distinct nucleotide positions with Brachyspira sp. sequences published previously. In addition, culture for Brachyspira was successful in three cases. On the basis of these data, we designed and evaluated a Brachyspira genus-specific 16S rRNA-directed FISH probe that detects all of the Brachyspira spp. published to date. FISH of biopsy samples resulted in strong, unequivocal signals of brush-like formations at the crypt surfaces. This technique allowed simultaneous visualization of single spirochetes and their identification as Brachyspira spp. In conclusion, FISH provides a fast and accurate technique for the visualization and identification of intestinal spirochetes in tissue sections. It therefore represents a valuable tool for routine diagnosis of HIS.

Pharmacokinetics and serum bactericidal activities of quinolones in combination with clindamycin, metronidazole, and ornidazole.

To enhance the antimicrobial spectrum of the quinolones against anaerobic organisms and gram-positive bacteria, we investigated in two studies the parenteral combinations of ciprofloxacin (200 mg) and ofloxacin (200 mg) with metronidazole (500 mg) or clindamycin (600 mg) and the oral combinations of enoxacin (400 mg) and fleroxacin (400 mg) with metronidazole (400 mg), clindamycin (300 mg), or ornidazole (500 mg) (only with fleroxacin). The pharmacokinetics and serum bactericidal activities (SBAs) against 5 aerobic and 2 anaerobic species (total, 58 strains) were determined in two groups of 10 healthy volunteers by using a randomized crossover study design. The additions of metronidazole, clindamycin, and ornidazole did not affect the pharmacokinetics of the quinolones. The combination of clindamycin with ciprofloxacin, ofloxacin, and, to a lesser extent, fleroxacin resulted in an increase of the SBA against gram-positive strains (mean peak titers): Staphylococcus aureus, ciprofloxacin alone, 1:5.5; ciprofloxacin-clindamycin, 1:19.9; ofloxacin alone, 1:3.6; ofloxacin-clindamycin, 1:17.5; fleroxacin alone, 1:4.3; fleroxacin-clindamycin, 1:8.1; Streptococcus pneumoniae (fleroxacin and enoxacin were not tested), ciprofloxacin alone, 1:2.0; ciprofloxacin-clindamycin, 1:53; ofloxacin alone, 1:2.6; and ofloxacin-clindamycin, 1:49.2. The high SBA of quinolones against gram-negative bacteria was not affected by the combinations; however, relatively low activities against Pseudomonas aeruginosa were detected. In general, against anaerobic bacteria, low bactericidal activities were determined in both studies (mean peak titers ranged from 1:2.1 to 1:3.1; mean trough titers range from 1:2.0 to 1:2.9). In clinical settings with severe mixed infections, a parenteral therapy consisting of modern quinolones together with clindamycin or imidazole derivatives seems to be active and offers no obvious interactions.

Antibiotikaempfindlichkeit von Neisseria-gonorrhoeae-Isolaten in Berlin

ZusammenfassungHintergrund und Fragestellung. Angesichts zunehmender Berichte über Resistenzzunahmen bei Neisseria gonorrhoeae sollten die aktuelle Resistenzsituation bei in Berlin isolierten Gonokokkenstämmen ermittelt werden. Patienten/Methodik. Zwischen 1995 und 1997 wurden 85 Gonokokkenisolate asserviert und gegenüber Penicillin G, Tetrazyklin, Spectinomycin, Ceftriaxon, Ciprofloxacin und Azithromycin im Agrardilutionsverfahren getestet. Ergebnisse. Gegenüber Penicillin G wurden 18,8% der Isolate als resistent bzw. intermediär eingestuft (6 PPNG). Gegenüber Tetrazyklin waren 12,9% der Isolate resistent und 43,5% intermediär. Ein Isolat war gegenüber Ciprofloxacin resistent, 4 weitere Isolate hatten MHK-Werte von 0,06–0,5 mg/l, 78 zeigten MHK-Werte von <0,007 mg/l. Gegenüber Ceftriaxon, Spectinomycin und Azithromycin waren alle Isolate empfindlich. Schlussfolgerungen. Penicillin G und Tetrazyklin sollten nur nach Kenntnis der Empfindlichkeit des Erregers eingesetzt werden. Bei Ciprofloxacin muss insbesondere bei Reiserückkehrern aus Südostasien mit Resistenzen gerechnet werden. Ceftriaxon, Azithromycin und Spectinomycin waren uneingeschränkt wirksam. Überprüfungen der aktuellen Resistenzsituation sind weiterhin notwendig.AbstractBackground and Objective. Because of the increasing resistance of Neisseria gonorrhoeae, we studied the actual resistance of isolats in Berlin. Patients/Methods. 85 Neisseria gonorrhoeae isolates were collected between 1995 and 1997. Susceptibility testing was performed for penicillin G, tetracycline, spectinomycin, ceftriaxon, ciprofloxycin and azithromycin by agar dilution. Results. 18.8% isolates were resistant or intermediately resistant to penicillin G (including 6 PPNG). 12.9% isolates were resistant, 43.5% intermediately resistant to tetracyclin. One strain was resistant against ciprofloxacin, 4 isolates showed increased MIC values (0.06–0.5 mg/l), whereas 78 isolates were fully susceptible (<0.007 mg/l). All isolates were susceptible to spectinomycin, ceftriaxone, and azithromycin. Conclusions. Penicillin G and tetracycline should be given only in cases of proven sensibility. Resistance against ciprofloxacin may occur, especially in isolates aquired in south-east Asia. Ceftriaxone, spectinomycin and azithromycin were active against all isolates. The actual resistance situation should be monitored.