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We present the case of a 77-year-old woman who developed an Actinomyces naeslundii infection of a hip prosthesis. The isolate grew well aerobically with 5% CO(2). Possible diagnostic problems may arise in the microbiological laboratory because aerobic growth is not sufficiently accounted for in some of the traditional identification schemes and commercial test kits. Therefore, besides presenting an unusual pathogen in this setting, this report focuses on possible diagnostic problems in the microbiological laboratory.

OBJECTIVE: To assess the in vitro susceptibility of clinical isolates to cefepime and five other antimicrobial agents with broad-spectrum activity. METHODS: The minimal inhibitory concentrations of 1521 Gram-positive cocci and 3170 Gram-negative rods were determined by the Etest procedure. RESULTS: The susceptibilities were as follows. Gram-positive bacteria: cefepime, 92.7%; ceftazidime, 60.5%; ceftriaxone, 87.8%; imipenem, 92.6%; amikacin, 56.5%; ciprofloxacin, 72.5%. Gram-negative bacteria: cefepime, 97.8%; ceftazidime, 94.3%; ceftriaxone, 83.1%; imipenem, 95.7%; amikacin, 96.6%; ciprofloxacin, 95.8%. CONCLUSIONS: Cefepime had the best activity when compared with the other broad-spectrum beta-lactams ceftazidime, ceftriaxone, imipenem, and the non-beta-lactams amikacin and ciprofloxacin.

This paper describes the frequency of susceptibility of Gram-negative and Gram-positive bacteria against antibacterial agents. The data are based on all susceptibility tests performed in 1996 at the Department of Medical Microbiology of the University of Zurich and at the private medical laboratory "medica" in Zurich. The evaluation of the results from 1975 to 1996 shows that susceptibilities against the antimicrobial agents tested have not changed markedly in this period with few exceptions. The tables may be a help for the physician in his decision for a "calculated chemotherapy" of bacterial infections.

The in vitro activity of cefpirome, a new parenteral fourth-generation cephalosporin, was investigated in the 5 university hospitals of Switzerland, and compared to 9 other antibiotics mainly used in hospitals, such as ceftazidime, ceftriaxone, cefotaxime, piperacillin, imipenem, gentamicin, vancomycin, ciprofloxacin and ofloxacin. A total number of 992 strains collected only from intensive care units and haematology-oncology units were tested by microdilution according to NCCLS. Cefpirome showed an excellent activity against all Enterobacteriaceae (MIC90 = 4 mg/l), methicillin-susceptible staphylococci (MIC90 = 1 mg/l), Streptococcus pneumoniae (MIC90 = 0.25 mg/l) and Haemophilus influenzae (MIC90 = 0.12 mg/l) isolates. Its activity was superior to that of third-generation cephalosporins against cephalosporinase-depressed mutants of Enterobacter cloacae and Citrobacter freundii isolates (MIC90 > 32 mg/l for third-generation cephalosporins vs 4 mg/l for cefpirome). The MICs of cefpirome of 3 strains of Klebsiella spp. with an extended-spectrum-beta-lactamase were lower (MIC90 = 2 mg/l) than those of third-generation cephalosporins (MICs90 > 32 mg/l). Against Pseudomonas aeruginosa cefpirome was as active as ceftazidime. The activity of cefpirome was poor against methicillin-resistant staphylococci, enterococci and nosocomial Gram-negative bacteria such as Stenotrophomonas maltophilia.

Useful results of microbiological examinations can only be expected, when the specimens submitted to the laboratory are taken correctly. This overview shows appropriate and inappropriate specimens. Hints are given for a 'calculated antimicrobial chemotherapy'. A brief outline shows which bacteria should be tested for susceptibility to antimicrobial agents due to variable sensitivity.

Background: Quantitative bacteriologic workup of BAL fluid (BALF) has evolved as a sensitive and specific technique for the diagnosis of bacterial pneumonia. Conventional quantitative cultures are expensive, time-consuming, and often unavailable on a 24-h basis. Therefore, we evaluated a dip slide method for the semiquantitative measurement of bacterial cultures in BALF specimens and compared the results with those from conventional quantitative cultures., Methods: Fifty BALF specimens from 45 patients with suspected pulmonary infection were examined prospectively with both methods. We compared the microbiologic results of conventional quantitative cultures with those of the dip slide method that is commercially available for blood cultures. Cost-effectiveness analysis of both methods was performed., Results: In 37 BALF specimens, 64 bacterial strains were detected with both techniques. The dip slide method and conventional cultures showed a high correlation with respect to the colony counts of the individual organisms per milliliter BALF (r=0.935; p= 0.0001) and the sum of colony counts in individual patients (r=0.947; p=0.0001). Although five strains were not detected by the dip slide technique, the diagnostic accuracy was not influenced. In 13 BALF samples, there was no growth of bacteria with both techniques. While the diagnostic yield of both methods was similar, the dip slide technique was 44 to 66% less expensive than conventional cultures., Conclusions: The examination of BALF with a clip slide method is highly comparable to conventional quantitative culture techniques, less expensive, and can be used independently of a specialized microbiology laboratory on a 24-h basis.

Helicobacter pylori (H. pylori) eradication rates with omeperazole/amoxicillin range from 0-90%. The best regimen for retreatment after failure of omeprazole/amoxicillin has not been established so far. The aim of this prospective study was to evaluate the efficacy of triple therapy with bismuth, tetracycline and ornidazole in eradicating H. pylori after failure of omeprazole/amoxicillin. 79 duodenal ulcer patients with H. pylori infection were treated with oral omeprazole (40 mg bid) and amoxicillin solute (750 mg tid) for 10 days. Eradication rate was 28/79 (35%) and was distinctly lower in smokers (> 10 cigarettes/day) vs nonsmokers (10/49 [20%] vs 18/30 [60%], p < 0.001). 37 patients with persistent H. pylori infection in whom omeprazole/amoxicillin had failed agreed to retreatment with triple therapy. Persistence of H. pylori was confirmed by histology (3 antral and 2 gastric body biopsies; H&E, Giemsa), urease test (CLO) and/or H. pylori culture. Patients smoking > 10 cigarettes/day were classified as smokers. Retreatment consisted of oral bismuth-subcitrate 4 x 120 mg/d for 28 days (day 1-28), tetracycline 4 x 500 mg/d and ornidazole 3 x 500 mg/d for 10 days (day 1-10). Control endoscopy was done 30 days after the end of treatment. Criteria for H. pylori eradication was negative urease test, culture and histology. 34/37 patients (6 females/28 males; 39 [23-64] years) completed the study (24/34 smokers, 10/34 nonsmokers). 3/37 patients dropped out because of side effects (n = 1) or incompliance (n = 2). H. pylori subcultures for resistance testing were possible in 32/34 patients: H. pylori was metronidazole-sensitive in 11/32 (1 female, 10 males; 38 [24-55] years; 9 smokers, 2 nonsmokers) and metronidazole-resistant (minimal inhibitory concentration for metronidazole > 8 mg/ml) in 21/32 (5 females, 16 males; 40 [23-64] years; 13 smokers, 8 nonsmokers). The overall H. pylori eradication rate of the triple therapy was 27/34 (79%). H. pylori was eradicated in 19/24 (79%) smokers and in 8/10 (80%) nonsmokers. Eradication rate for metronidazole-sensitive H. pylori was 11/11 (100%) vs 14/21 (67%) for metronidazole-resistant H. pylori (p = 0.012). Triple therapy is effective and safe in eradicating H. pylori in patients after failure of omeprazole/amoxicillin. Smoking had no negative effect on the eradication rate of the triple therapy after failure of omeprazole/amoxicillin. Eradication failures were due to metronidazole-resistance.

This paper describes the incidence of Gram-negative and Gram-positive bacteria susceptible to antibacterial agents. The data are based on all susceptibility tests performed at the Department of Medical Microbiology of the University of Zurich. The evaluation of the results from 1987 to 1993 shows that susceptibilities against the antimicrobial agents tested have not changed markedly in this period with few exceptions. The tables may be of help to the physician in his decision for a 'calculated chemotherapy' of bacterial infections.

A cystic fibrosis patient was infected by Stenotrophomonas maltophilia over at least 15 months. The bacteria became increasingly resistant to antimicrobial agents. Determination of restriction fragment length polymorphism and ribotyping showed that resistance was due to changes in that S. maltophilia rather than to infection by another strain.

The sensitivity to the major antimicrobial agents of consecutively isolated gram-negative rods in intensive care units in Switzerland was investigated. A majority of strains originated from clinical specimens where infection or colonization could not be distinguished from each other. A total of 1024 isolates from 482 patients were tested by a standardized microtiter method. Of the beta-lactam antibiotics, imipenem (92% of bacteria sensitive), ceftazidime (90%), and aztreonam (85%) showed the greatest activity. 94% of the isolates were sensitive to ciprofloxacin, and 93% and 91% to amikacin and tobramycin respectively. There where considerable differences locally and in time, probably reflecting small outbreaks due to resistant bacteria and because selective pressure is locally dependent on the antimicrobial agents used. 122 patients were observed for an extended period. In 67 (55%) the same gram-negative rods persisted for up to 42 days without development of resistance. In 41 patients (34%) there was a change to other more resistant bacteria, especially to multi-resistant Pseudomonas aeruginosa, Flavobacterium meningo-septicum, Xanthomonas maltophilia or Enterobacter cloacae. In 12 patients (10%) bacteria of the same species with resistance to additional antimicrobial agents were observed.

The susceptibility of 2196 fresh clinical isolates to twelve different oral compounds was assessed in five Swiss microbiology institutions during summer 1992. A standardized microdilution system including all other material necessary was employed to assess the antibacterial activity of penicillin G, ampicillin, ampicillin + sulbactam, amoxycillin + clavulanic acid, cefadroxil, cephalexin, cefaclor, cefuroxime, cefetamet, doxycycline, erythromycin and clindamycin. The aminopenicillins (including the beta-lactamase inhibitor combinations) were highly active against the streptococci, in combination with a beta-lactamase inhibitor they covered the majority of the bla+ E. coli and Proteus mirabilis and between 60 to 80% of the Klebsiella spp. and Proteus vulgaris isolates. All the cephalosporins exhibited good activity against the streptococci, they were active against Gram-negative fermentative rods to a varying degree. Cefetamet was also active against many cefaclor and cefuroxime-resistant isolates. A considerable part of the species studied exhibited resistance to doxycycline; the observed resistance of S. agalactia, P. mirabilis, and Morganella morganii agreed with previous findings. Most of the Streptococcus spp. were inhibited by erythromycin and clindamycin. There were only single penicillin resistant S. pneumoniae isolates in the five Swiss centers. Taking account of the above particulars the epidemiology of antimicrobial resistance in Switzerland can be considered satisfactory.

Colonization of Helicobacter pylori (HP) beneath the protective film of gastric mucus enables the organism to survive in the hostile environment of the gastric mucosa. N-acetylcysteine (NAC), a sulfhydryl compound with potent mucolytic activity, induces a reduction of gastric barrier mucus thickness of about 75% and reduces mucus viscoelasticity. We therefore tested the hypothesis whether better eradication results could be achieved by addition of NAC to omeprazole/amoxicillin (OME/AMOX). 34 HP positive outpatients with endoscopically documented recurrent duodenal ulcer were included in an ongoing, prospective, randomized trial. Exclusion criteria were: alcoholism, previous gastric surgery, or intake of antibiotics, OME, bismuth salts, corticosteroids or NSAIDs within 4 weeks before study entry. Patients currently smoking > 10 cigarettes/day were classified as smokers. HP infection was confirmed by histology (3 biopsy specimens from gastric antrum and 2 from gastric body; H&E, Giemsa) and at least positive rapid urease test or culture. All 34 patients underwent ulcer therapy with OME (20 mg per day) for 20 days (d 1-20). Group A: in 17 patients (5 females, 12 males, mean age 46 [29-74] years; 8 smokers, 9 nonsmokers) the subsequent eradication therapy, consisting of oral OME (40 mg bid) and AMOX solute (750 mg tid) for 10 days, was combined with NAC solute (2 x 600 mg bid (d 21-30). Group B: 17 patients (2 females, 15 males, mean age 39 [19-70] years; 11 smokers, 6 nonsmokers) underwent eradication therapy without NAC (d 21-30). Control endoscopy was done after a minimal interval of 30 days from the end of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Recommended therapies with the highest eradication rates for Helicobacter pylori (HP) are triple therapies comprising bismuth salts, nitroimidazole and amoxicillin or tetracycline. Primary and secondary resistance of HP to nitroimidazole, however, represents a major problem of this treatment since it is the main cause of eradication failure. In these cases therapeutic regimes without nitroimidazole could prove more successful. High dose omeprazole/amoxicillin has been suggested as a simple and effective therapy with few side effects. The effectiveness of this combination in eradicating metronidazole resistant HP has not been established so far. The aim of this study was to evaluate high dose omeprazole/amoxicillin in eradicating metronidazole resistant HP in our population. 33 patients (6 women, 27 men, mean age 39 [range 21-68]) with recurrent duodenal ulcer and gastric colonization by metronidazole resistant HP were examined. Smokers were defined as patients currently smoking > 10 cigarettes/day. Exclusion criteria were: gastric surgery or intake of antibiotics, omeprazole bismuth salts and NSAIDs within four weeks before study entry endoscopy. Biopsy specimens were obtained in a standardized manner: 5 from the gastric antrum (1 CLO, 1 culture, 3 histology: H & E, Giemsa) and 2 from the gastric body (histology). Resistance testing for penicillin, amoxicillin and metronidazole was performed using a disk diffusion test (E-test, AB Biodisk, Sweden). Metronidazole resistance was defined as a minimal inhibitory concentration (MIC) of metronidazole of > 8 micrograms/ml. Eradication therapy consisted of oral omeprazole (40 mg bid) and amoxicillin solute (750 mg tid) for 10 days. Subsequently, for ulcer treatment, patients were given omeprazole (20 mg per day) for 20 days.(ABSTRACT TRUNCATED AT 250 WORDS)

The efficacy of high dose omeprazole/amoxicillin (OME/AMOX) for eradication of Helicobacter pylori (HP) is controversial. Reported eradication rates range from 0% to 90%. Different therapy schedules and unknown factors may be crucial; in particular, pretreatment with OME has been thought to endanger HP eradication by subsequent OME/AMOX. Preliminary findings suggested that smoking may impair eradication with OME/AMOX. The aims of this study were (1) to establish whether HP eradication rates differ depending on whether eradication with OME/AMOX was performed before or after ulcer therapy with OME, (2) to determine whether smoking impairs HP eradication by OME/AMOX and (3) to evaluate the efficacy of OME/AMOX in our population. 52 HP positive outpatients with endoscopically documented recurrent duodenal ulcer were included. Exclusion criteria were: alcoholism, previous gastric surgery, or intake of antibiotics, OME, bismuth salts, corticosteroids and NSAIDs within four weeks before study entry. Patients currently smoking > 10 cigarettes/day were classified as smokers. HP infection was confirmed by histology (3 biopsy specimens from the gastric antrum and 2 from the gastric body; H&E, Giemsa) and at least positive rapid urease test (CLO) or culture. Eradication therapy consisted of oral OME (40 mg bid) and AMOX solute (750 mg tid) for 10 days (OME/AMOX). This therapy preceded (group A) or followed (group B) ulcer therapy with OME (20 mg per day for 20 days). In group A 17 patients (2 females, 15 males, mean age 39 [19-70]; 11 smokers, 6 nonsmokers) underwent ulcer therapy with OME (d 1-20) before OME/AMOX d 21-30).(ABSTRACT TRUNCATED AT 250 WORDS)

Study Objective: To determine if performing bronchoalveolar lavage (BAL) from more than one lung segment augments the diagnostic yield in patients with pulmonary infection., Patients and Study Design: Seventy-six patients who underwent bisegmental BAL for the diagnosis or exclusion of pulmonary infection were studied prospectively., Main Results: In patients with AIDS, the concentration of Pneumocystis carinii was higher in the upper lobes than in the middle lobes, regardless of whether the patients had been receiving pentamidine prophylaxis. In patients without HIV infection, the number of P carinii clusters was much lower. In 2 of 5 HIV-negative patients, P carinii organisms were detectable but in one of two lavage specimens, whereas in only 1 of 19 AIDS patients, P carinii organisms were not found in both lavaged segments. In bacterial pneumonia, BAL fluid from a segment of the radiologically most involved area had a much higher cell concentration, percentage of neutrophils, and concentration of bacteria than from the segment that was not or less severely involved on chest radiograph. In two of nine patients with AIDS and cytomegalovirus (CMV) pneumonia, cytopathogenic CMV effects were not found in both lavaged segments. In one of eight patients, mycobacteria could be cultured only from one of two radiologically involved segments., Conclusion: An increase in the diagnostic sensitivity by performing BAL in two lung segments is limited to cases where P carinii pneumonia is a relevant consideration in immunocompromised patients without HIV infection. In bacterial pneumonia, BAL can be performed in a single radiographically involved lung segment without a loss in diagnostic sensitivity. Since our study population of patients with CMV pneumonitis, mycobacterial infections, and fungal infections was small, no reliable conclusions are possible and BAL of more than one lung segment seems justified until more information is available.

In a prospective trial we examined the efficacy and acceptability of a modified triple therapy in H. pylori (HP)-positive patients with recurrent duodenal ulcer disease. Oral administration of amoxicillin for two weeks was substituted for one single injection of intramuscular depot penicillin (benzathine penicillin G). Additionally, patients were given ornidazole 500 mg tid for 14 days and 120 mg colloidal bismuth sub-citrate qid for 28 days. The patients were investigated for H. pylori colonization using a rapid urease test (CLO), histology (H&E-, Giemsa stain), culture (including determination of the minimal inhibitory concentrations for metronidazole, penicillin G and amoxicillin) and H. pylori serology (Cobas Core Anti-H. pylori EIA, F. Hoffmann-La Roche). Control endoscopies using the same methods were performed 1 and 6 months after eradication therapy. The eradication rate was 50% and the ulcer healing rate 90% 1 month after therapy. Ulcers recurred in 2/3 of patients with persistent infection vs 0/5 of HP-eradicated patients after 6 months. Both successfully HP-eradicated patients and patients with treatment failure exhibited comparable decreases in mean serum IgG anti-HP concentration within 2 months. Discrimination between the two groups and hence identification of the eradication success by serology was not possible within a time period of 2 months. After 6 months, serum IgG anti-HP concentrations in non-HP-eradicated patients returned to pre-therapy values, in HP-eradicated patients the concentrations further decreased. The above-described modified triple therapy against HP cannot be recommended as a standard therapy, mainly because of the insufficient eradication effect.(ABSTRACT TRUNCATED AT 250 WORDS)

We report the history of a 38-year-old male native of Sri Lanka admitted to the emergency ward because of chest pain and shortness of breath. On physical and radiographic examination a bilateral predominantly right-sided pneumonia was found. The patient was admitted to the medical ICU and an antibiotic regimen with amoxicillin/clavulanic acid and erythromycin was initiated. Shortly afterwards septic shock developed. The patient was intubated and received high doses of catecholamines. He died 30 hours after admission to the hospital. Cultures from sputum, tracheal aspirate and blood grew Acinetobacter baumanni. Acinetobacter is an ubiquitous gram-negative rod with coccobacillary appearance in clinical specimens, that may appear gram-positive due to poor discoloration on Gram-stain. It is a well known causative agent of nosocomial infections, particularly in intensive care units. Community-acquired pneumonias, however, are quite rare. Sporadic cases have been reported from the US, Papua-New Guinea and Australia. Interestingly, these pneumonias are fulminant and have a high mortality. Chronic obstructive lung disease, diabetes, and tobacco and alcohol consumption appear to be predisposing factors. Due to the rapid course and poor prognosis, prompt diagnosis and adequate antibiotic treatment are indicated. Antibiotics use for community-acquired pneumonias, such as amoxicillin/clavulanic acid or macrolides, are not sufficient. Appropriate antibiotics for the initial treatment of suspected Acinetobacter infections include imipenem and carboxy- and ureidopenicillins combined with an aminoglycoside.

The performance of two enzyme immunoassays for rapid detection of group B streptococci (GBS) was evaluated in comparison to culture using cervical swabs from 191 pregnant women. Ten percent of the women harboured GBS. There were two positive results in the Icon assay (Hybritech), both in women with heavy growth in the culture, and four positive results in the Quidel assay (Quidel), two in the women with heavy colonization and one each in women with moderate and light growth of GBS respectively. The sensitivity of both assays was low, being 11% (2/18) for the Icon assay and 24% (4/17) for the Quidel assay. The specificity of both assays was 100%. Both assays could detect > or = 10(6) group B streptococci per swab. A positive result justifies ampicillin prophylaxis due to the high risk for the newborn. A negative result should be confirmed by rapid culture techniques.

The susceptibility of 146 recent clinical isolates of gram-negative and gram-positive anaerobes was determined by the E test (AB Biodisk) on both Wilkins-Chalgren and PDM ASM II (AB Biodisk) agar. Results of the E test were compared with results obtained by the NCCLS agar dilution method using Wilkins-Chalgren agar. Incubation was for 20 hours and 44 hours in the E test and for 44 hours in the NCCLS method. In general, 44 hour results were more reliable; however, NCCLS readings were made only once after 44 hours. After two days of incubation, 91% of E test results on Wilkins-Chalgren agar were within one dilution and 98% within two dilutions of the corresponding NCCLS values; on PDM agar these values were 89% and 98%, respectively. Major and very major discrepancies combined were less than 1%.

The in vitro activity of the ester Ro 41-3399 and its free active acid Ro 40-6890 was tested against 189 strains of anaerobic bacteria in comparison to other oral cephalosporins and to antimicrobial agents established in the treatment of anaerobic infections. Prevotella, Porphyromonas, Peptostreptococcus, Fusobacterium and Clostridium spp. were susceptible to Ro 40-6890, with few exceptions. Due to its lack of activity against the major pathogens of the Bacteriodes fragilis group, Ro 40-6890 does not promise to be of major use in the treatment of infections caused by anaerobes.

There have been numerous reports on resistance of anaerobic bacteria against antimicrobial agents. Therefore, to assess the situation in Zurich, 187 anaerobic strains of various bacterial genera, isolated from clinical specimens during winter 1990/91, were tested for their susceptibility to antimicrobial agents active against anaerobic bacteria. Besides the Bacteroides fragilis group, which is naturally resistant against penicillin, 30% of isolates of other Bacteroides species were also resistant against penicillin. In general, anaerobes have remained susceptible to cefoxitin, chloramphenicol, clindamycin, imipenem, the 5-nitroimidazoles (metronidazole, ornidazole) as well as combinations of beta-lactam antibiotics with beta-lactamase inhibitors (clavulanic acid, sulbactam and tazobactam). Because rare strains resistant against cefoxitin, clindamycin and beta-lactams plus beta-lactamase inhibitors can be found, at least isolates from specific clinical situations should be tested for antimicrobial susceptibility. These are strains isolated from patients with brain abscess, endocarditis, osteomyelitis, arthritis, infected implants and prosthesis as well as those from persisting or recurrent bacteremia. Because the agar diffusion test yields unreliable results, minimal inhibitory concentration should be determined. Maybe the new 'E test' or the spiral gradient procedure can be used after evaluation.

We report on two patients with actinomycosis. The first case was a 45-year-old cachectic man with extensive bilateral pulmonary infiltrates. The lesions remained unclear for 18 months and only open lung biopsy with microscopic and cultural evaluation led to the diagnosis of actinomycosis. In the second case, classic cervico-facial actinomycosis in a 69-year-old farmer is described. Diagnosis was established on the basis of microscopic findings of "sulphur granules" eroding the mandible. Furthermore, the clinical presentation, with an indurated swelling of the jaw and intraoral fistula formation, was typical. The patient had a severe combined aortic valve lesion and died after ventricular fibrillation during hospitalization. Diagnosis could not be confirmed by culture, probably due to antibiotic prophylaxis against endocarditis during tooth extraction on the first day of admission. Diagnostic difficulties and microbiologic aspects are discussed, with special focus on the rare species of Actinomyces meyeri which was cultured from biopsy specimens from the lung of the first patient. So far this species has been described in only 13 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

This paper describes the incidence of susceptibility of gram-negative and positive bacteria towards antibacterial agents. The data are based on all susceptibility tests performed at the Department of medical microbiology of the University of Zurich. The evaluation of the results from 1975 to 1990 shows that susceptibilities against the antimicrobial agents tested have not changed markedly in this period. These tables may be a help for the physician in his decision for a "calculated chemotherapy" of bacterial infections.

A rare case of prosthetic valve endocarditis caused by Micrococcus luteus is described and compared with the few cases reported in the literature, as well as the clinical features, microbiological profile, therapy, and prognosis of common prosthetic valve endocarditis. Micrococcus luteus is a constituent of the normal human buccal bacterial flora which forms yellowish colonies and appears as a gram-positive coccus typically arranged in tetrades. Although of low virulence, the germ may become pathogenic in patients with impaired resistance, colonizing the surface of heart valves. In contrast to staphylococci (for which it may easily be mistaken) it is usually penicillin-sensitive. However, the most promising antibiotic regimen proposed for treatment of Micrococcus luteus seems to be a combination of vancomycin, amikacin, and rifampicin. If the infection leads to severe hemodynamic alterations, however, valve replacement may become necessary similar to the situation in prosthetic valve endocarditis caused by more aggressive and highly resistant bacteria.

Sparfloxacin disk susceptibility test criteria for the NCCLS and ICS/DIN methods were determined by testing 400 bacterial wild-type isolates. Disks containing 5 micrograms of the drug could be used satisfactorily in both procedures. The following interpretive zone size breakpoints for the NCCLS and ICS/DIN methods were proposed: less than or equal to 18 and 20 mm respectively for resistance (MIC greater than 1 mg/l), and greater than or equal to 23 and 25 mm respectively for susceptibility (MIC less than or equal to 0.5 mg/l). These criteria were based on preliminary maximum serum concentrations of approximately 1.5 mg/l after a single oral dose of 400 mg of the drug. Regression equations for both methods correlating MICs and zone sizes based on test results for 361 organisms are presented. The equations allow calculation of breakpoints for higher or lower serum peak levels. Sparfloxacin was two to four times more active than ciprofloxacin against gram-positive cocci, and showed equal activity against gram-negative rods. Zone diameter quality control values for Escherichia coli ATCC 25922 were 26-30 mm (NCCLS) and 30-33 mm (ICS/DIN), and for Staphylococcus aureus ATCC 29213 27-28 mm (NCCLS) and 29-31 mm (ICS/DIN).

This paper compares three common methods for the detection of Clostridium difficile, i.e. latex agglutination, culture and cytotoxic activity. The sensitivity of the latex agglutination test alone is 70%, of the culture 100% and of the cytotoxin test 66%. Specificities are 93, 96 and 100%, respectively. The latex agglutination has positive and negative predictive values of 58 and 96%; the respective values for the culture are 77 and 100%, for the cytotoxin assay 100 and 96%. Whereas all tests are fairly reliable for the exclusion of diarrhea associated to Clostridium difficile (CAD), the positive predictive values of latex agglutination and culture are too low. If one requests two positive test results for proof of CAD, about two third of all cases are detected by any combination of laboratory tests, while the specificity approaches 100%. We recommend that two of the three tests are performed; the choice is influenced by the possibilities of the laboratory.

In a 63-year-old patient presenting with signs of classical diphtheria including membranous pharyngotracheobronchitis and myocarditis, Corynebacterium ulcerans was isolated in pure culture from the membranes. The strain produced a toxin specific for C. ulcerans but no diphtheria toxin. The patient was discharged after a complicated hospital course including respiratory and cardiac failure. Besides Corynebacterium diphtheriae, which has very rarely been isolated in Switzerland in recent years, Corynebacterium ulcerans should be considered as a cause of classical diphtheria.

In clinical microbiology, gas-liquid chromatography (GLC) is used mainly for the following applications: (1) demonstration of microbial metabolites in cultures: studies of short-chain fatty acids (chain length 2 to 6 carbon atoms) and of the non-volatile lactic and succinic acids are the basis of taxonomy of obligate anaerobes on the genus level. Demonstration of these compounds in spent culture media is also used for identification of anaerobic bacteria in the clinical laboratory. (2) Investigation of long-chain fatty acids of cell membranes and the cell wall: analysis of fatty acids with chain lengths of 9 to 20 carbon atoms are used primarily for taxonomic purposes. A practical application for use in clinical bacteriology is the Microbial Identification System (MIS) based on equipment built by Hewlett-Packard. Although this system is excellently suited for quantitative analysis of long chain fatty acids and gives valuable preliminary or confirmative information, it often requires additional testing for identification of bacteria to species level. (3) Direct rapid diagnosis of infection: demonstration of metabolic products in body fluids can be of value in infections with anaerobes (demonstration of fatty acids) and yeasts (sugars). GLC combined with mass spectrometry or frequency-pulsed electron capture GLC techniques have been applied to studies of sera, fecal specimens, and cerebrospinal fluids. These latter applications are still in an experimental stage. However, the rapid diagnosis of tuberculosis directly from cerebrospinal fluid and sputum is well advanced. The potential of direct diagnosis without the resort to cultures warrants continued research with these techniques.

The indications and methods for sensitivity testing of mycobacteria, fungi, anaerobes, and other fastidious bacteria are described in a study which is part of a series on sensitivity testing (this journal, 1984; 114: 1079-1086 and 1987; 117: 509-517). Since these tests are rarely indicated and involve methodological problems, they are best performed by larger laboratories or by reference units.

The activities of the 2,4-diamino-5-benzylpyrimidines brodimoprim and metioprim against anaerobic bacteria were tested alone and in combination with sulfonamides. Alone they were two to four times more active than trimethoprim, but in combination with sulfonamides, their activity was slightly lower than that of trimethoprim plus sulfamethoxazole.

Current methods for isolation and identification of obligately anaerobic bacteria are laborious and time-consuming. Direct gas-liquid chromatography of purulent and serous specimens for short-chain fatty acids allows a presumptive diagnosis of anaerobic infection. Good correlation was found for the cultural recovery of anaerobic bacteria and the presence of propionic acid in concentrations of greater than or equal to 1 muMol/ml, isobutyric, butyric, isovaleric, valeric, isocaproic and caproic acid at greater than or equal to 0.1 muMol/ml, and succinic acid at greater than or equal to 2 muMol/ml (either as single acids or in combination). Specimens yielding no anaerobic bacteria in culture contained only acetic, lactic and small amounts of succinic acid, but none of the volatile acids.

There are several reports in the literature on resistance of anaerobic bacteria against antimicrobial agents. Therefore, 231 anaerobic strains of various bacterial genera, isolated from clinical specimens during fall 1984, were tested for susceptibility to antimicrobial agents active against anaerobic bacteria. Whereas 23% of the Bacteroides species not belonging to the B. fragilis group were resistant to penicillin, the anaerobic bacteria were still susceptible to chloramphenicol, clindamycin and the nitroimidazoles. The resistance rate against the various new beta-lactam antibiotics was comparable to results of other studies. Due to the increasing resistance it is recommended that the susceptibility of clinically important anaerobes be tested by appropriate techniques. The agar diffusion test must not be used due to unreliable results. Instead, the minimal inhibitory concentration should be determined or the "broth-disk" test performed.

The minimum inhibitory concentrations of penicillin and cephalothin necessary to inhibit growth of most anaerobic bacteria were reduced to a susceptible level by 1 to 5 mug of clavulanic acid per ml. In most cases, minimum inhibitory concentrations of cefoxitin were not affected.

The minimal inhibitory concentrations (MICs) of sulfamethoxazole and trimethoprim against 144 strains of obligately anaerobic bacteria were determined on Diagnostic Sensitivity Test agar (Oxoid) or in prereduced Diagnostic Sensitivity Test broth, both supplemented with sodium pyruvate (1 mg/ml), hemin (5 mug/ml), and vitamin K(1) (1 mug/ml). Fifty-eight percent of the strains were susceptible to sulfamethoxazole alone (MIC

The frequency with which various bacteria are isolated from samples of hospitalized patients and the occurrence of sensitivity to antimicrobial agents in these bacteria are described. Data were collected and summarized by an electronic data processing system. Sensitivity data were obtained with the disc diffusion test carried out by the Bauer/Kirby method. E. coli and S. aureus were the most frequently isolated organisms. Pseudomonas sp. (in 90% Pseud. aeruginosa) took second place behind E. coli among gramnegative rod bacteria. As a rule more than 50% of grampositive and gramnegative bacteria were sensitive to betalactam antibiotics and broad spectrum agents. Aminocyclitols were the most potent drugs. Strains resistant to netilmicin or amikacin were only exceptionally observed. A comparison of the occurrence of sensitive bacteria from 1975 to 1980 revealed that with rare exceptions no decrease of sensitivity to standard drug occurred in E. coli, the Klebsiella-Enterobacter-Serratia group, Pseudo. aeruginosa and S. aureus.

Pseudomembranous colitis (PMC) caused by a toxin produced by Clostridium difficile is described in the literature as a severe diarrheal disease with a high mortality rate. A case which tends to absolve PMC from this reputation is reported involving an outpatient who developed well documented PMC subsequent to ampicillin therapy but required no treatment. The number of unreported cases of antibiotic-associated colitis with and without pseudomembrane formation is probably very high, since only severe cases of diarrhea are thoroughly investigated. In a chronological literature review an attempt is made to update the nomenclature of antibiotic-associated colitis. There are recent reports of a connection between the Clostridium difficile toxin and the chronic inflammatory "non-bacterial" intestinal diseases ulcerative colitis and Crohn's disease. The authors finally consider whether in cases of antibiotic-associated diarrhea efforts should be made to isolate Clostridium difficile and/or demonstrate the presence of its toxin, for the purposes of prognosis and therapy.

A Branhamella catarrhalis-like organism was isolated from blood cultures; it was atypical in showing negative nitrate and nitrite and positive gamma-glutamylaminopeptidase reactions, in agglutinating with Neisseria meningitidis antisera, and in forming butyrous colonies. Cell-wall fatty-acid and lipopolysaccharide analysis provided evidence that this isolate was an atypical B. catarrhalis.

Campylobacter pylori (C.p.) infection is often found in patients with antral gastritis and peptic ulcer disease. Pathophysiological links are still unclear, and we therefore tested the hypothesis whether C.p. affects the gastrointestinal peptides and thus influences gastric acid secretion and protective factors. 94 patients were examined by upper GI endoscopy and blood analyzed for gastrin, somatostatin, pancreatic polypeptide and neurotensin. Biopsies of antral mucosa were investigated for C.p. in urease testing, culture and microscopy. C.p. was found in 42 patients (45%). In microscopy all of these patients had chronic gastritis (100%). A significant increase in gastrin uninfluenced by C.p. was found in patients with antral gastritis (normal: 6.4 +/- 0.7, [n = 27]; gastritis without C.p.: 18.4 +/- 5.9 [p less than 0.02], [n = 7]; gastritis with C.p.: 10.7 +/- 2.2, [n = 22]). Somatostatin, pancreatic polypeptide and neurotensin showed no difference.

This paper describes the frequency of susceptibility of Gram-positive and Gram-negative bacteria against antibacterial agents. The data are based on all susceptibility tests performed at the Department of Medical Microbiology of the University of Zurich. The evaluation of the results from 1975 to 1987 shows that susceptibility against standard antimicrobial agents has not decreased in this period. These tables may be a valuable help for the physician in his decision for a "calculated chemotherapy".

The susceptibility of C. difficile isolated at the Department of Medical Microbiology of the University of Zurich to a wide selection of antibacterial, antimycobacterial and antifungal agents was tested in vitro. Great differences in susceptibility were found against chloramphenicol, clindamycin, erythromycin, rifamycin, and tetracycline. Resistance to clindamycin and erythromycin could always be transferred jointly to a susceptible C. difficile strain by mixed culture on filters at low frequencies (1 X 10(-8) to 4 X 10(-8) per donor cell). Transfer of tetracycline resistance occurred at frequencies of 3 X 10(-7) to 5 X 10(-7). Chloramphenicol and rifamycin resistance could not be transferred in the system used (frequencies less than 10(-8)). Although a total of 38,000 colonies was screened by various methods known to affect plasmid replication, resistance to chloramphenicol, clindamycin, erythromycin, rifamycin, and tetracycline could not be eliminated. No connection between plasmid DNA and antimicrobial resistance could be established. Especially, no plasmid DNA was involved in the transfer of resistance determinants from resistant to susceptible strains.

To avoid false positive results it is very important that specimens for culture of anaerobic bacteria are not contaminated with normal flora from the skin or mucous membranes (mouth, intestinal tract, genital tract). The specimen should be transported to the laboratory as fast as possible without exposure to oxygen. Liquid specimens, such as aspirates, are superior to swabs. For rapid presumptive diagnosis suitable methods are gram stain and direct gas-liquid chromatography for fatty acids. Culture is laborious and time-consuming.

A case of Rhodococcus equi pneumonia associated with septicemia and metastatic brain abscess in an HIV-infected male is presented. Clinical findings and the diagnostic and therapeutic approach are discussed. Cavitating pulmonary disease was rapidly improved by six-week combined oral and parenteral antibiotic treatment. However, pulmonary relapse and brain abscess were documented after one month. Therapy with ceftriaxone, ciprofloxacin and cotrimoxazole on an outpatient basis again led to clinical and radiological improvement after four weeks. Surgical resection of localized processes should be considered early, and prolonged antibiotic therapy over months is recommended.

We report food-borne botulism in a 28-month-old boy and his father in order to illustrate this rare disease. Diagnosis and treatment are reviewed.