Characteristics and outcome of 16 periprosthetic shoulder joint infections

PURPOSE

Shoulder arthroplasties are increasingly performed, but data on periprosthetic joint infections (PJI) in this anatomical position are limited. We retrospectively investigated the characteristics and outcome of shoulder PJI after primary arthroplasty from 1998 to 2010 in a single centre.

METHODS

Periprosthetic joint infection was defined as periprosthetic purulence, presence of sinus tract or microbial growth. A Kaplan-Meier survival method was used to estimate relapse-free survival of prosthesis.

RESULTS

From 1,571 primary shoulder prostheses, we evaluated 16 patients with a PJI at different stages, i.e, early (n = 4), delayed (n = 6) and late (n = 6) infections. The median patient age was 67 (range 53-86) years, and 69 % were females. The most commonly isolated microorganism was Propionibacterium acnes in 38 % of patients (monobacterial in four and polymicrobial in two patients). In 14 of the 16 patients, surgical interventions consisting of debridement and implant retention (6 patients), exchange (7) and explantation (1) were performed. Four patients had a relapse of infection with P. acnes (n = 3) or Bacteroides fragilis (n = 1). The relapse-free survival of the prosthesis was 75 % (95 % confidence interval 46-90 %) after 1 and 2 years, 100 % in six patients following the treatment algorithm for hip and knee PJI and 60 % in 10 patients not followed up. All but one of the relapses were previously treated without exchange of the prosthesis.

CONCLUSIONS

As recommended for hip and knee PJI, we suggest treating shoulder PJI with a low-grade infection by microorganisms such as P. acnes with an exchange of the prosthesis. Cohort studies are needed to verify our results.

[Antimicrobial resistance among E. coli in urinary specimens: prevalence data from three laboratories in Zurich between 1985 and 2010]

Urinary tract infections in women are common. Drug resistance among Escherichia coli, the most frequent uropathogen, has increased worldwide. In a prevalence study we investigated the local antibiotic susceptibility of this microorganism in urinary specimens of three laboratories in Zurich. Resistance rates against trimethoprim-sulfamethoxazole 2010 were 28%, 16% against quinolones and 16% against amoxicillin/clavulanic acid. Resistance prevalence for nitrofurantoin and fosfomycin were low with 3,6%, resp. 0,7%. The rate of extended-spectrum beta-lactamase-producing E. coli has rapidly increased to 4,3% in 2010. Based on this data and according to the international guidelines for the treatment of uncomplicated cystitis, therapy with trimethoprim-sulfamethoxazole and quinolones are no longer recommended. Nitrofurantoin and Fosfomycin are an appropriate choice. Microbiological testing is advised.

Characteristics and outcome of 27 elbow periprosthetic joint infections: results from a 14-year cohort study of 358 elbow prostheses

Elbow arthroplasty is increasingly performed in patients with rheumatic and post-traumatic arthritis. Data on elbow periprosthetic joint infection (PJI) are limited. We investigated the characteristics and outcome of elbow PJI in a 14-year cohort of total elbow arthroplasties in a single centre. Elbow prosthesis, which were implanted between 1994 and 2007 at Schulthess Clinic in Zurich, were retrospectively screened for infection. PJI was defined as periprosthetic purulence, the presence of sinus tract or microbial growth. A Kaplan-Meier survival method and Cox proportional hazard analysis were performed. Of 358 elbow prostheses, PJI was identified in 27 (7.5%). The median patient age (range) was 61 (39-82) years; 63% were females. Seventeen patients (63%) had a rheumatic disorder and ten (37%) had osteoarthritis. Debridement and implant retention was performed in 78%, followed by exchange or removal of the prosthesis (15%) or no surgery (7%).The relapse-free survival (95% CI) was 79% (63-95%) after 1 year and 65% (45-85%) after 2 years. The outcome after 2 years was significantly better when patients were treated according to the algorithm compared to patients who were not (100% vs. 33%, p <0.05). In 21 patients treated with debridement and retention, the cure rate was also higher when the algorithm was followed (100% vs. 11%, p <0.05). The findings of the present study suggest that the treatment algorithm developed for hip and knee PJI can be applied to elbow PJI. With proper patient selection and antimicrobial therapy, debridement and retention of the elbow prosthesis is associated with good treatment outcome.

Effect of clavulanic Acid on anaerobic bacteria resistant to Beta-lactam antibiotics

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.

[Sensitivity of bacteria to antibiotics (Zurich, 2000)]

This paper describes the frequency of susceptibility of Gram-negative and Gram-positive bacteria against antibacterial agents. Data are based on all susceptibility tests performed at the Department of Medical Microbiology of the University of Zurich in 2000. The evaluation of the results from 1987 to 2000 shows that susceptibilities against the antimicrobial agents tested have not markedly changed with the following exceptions: 7% of Staphylococcus aureus are resistant against methicillin, 8% of pneumococci have a reduced susceptibility to penicillin, 1% is resistant to penicillin, and 10% are resistant to macrolides. 9% of group A streptococci are resistant to macrolides. Quinolone resistance is markedly high in the medical practice with 10% of E. coli strains and 32% of Campylobacter sp. Strains of Klebsiella pneumoniae and E. coli producing extended spectrum betalactamases are isolated occasionally. Of all strains of Mycobacterium tuberculosis isolated from clinical specimens in 2000, 4% were multi-drug resistant. The tables may be a help for the physician in his decision for a "calculated chemotherapy" of bacterial infections.

Infection of a hip prosthesis by Actinomyces naeslundii

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.

[Sensitivity of bacteria to therapeutic drugs (Zurich 1996)]

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.

Low specificity of the bacterial index for the diagnosis of bacterial pneumonia by bronchoalveolar lavage

The bacterial index (BI) as defined by the sum of log10 colony-forming units (cfu) of microorganisms per milliliter of bronchoalveolar lavage (BAL) fluid, i.e., a multiplication of the single cfu/ml, has been used to distinguish between polymicrobial pneumonia (BI> or =5) and colonization (BI<5). Since many false-positive results are to be expected using this parameter, the diagnostic value of the BI was studied prospectively by obtaining bacteriologic cultures of BAL fluid in 165 consecutive unselected patients. In 27 cases the diagnosis of bacterial pneumonia was established on clinical criteria. In 133 patients pneumonia could be excluded, and in five patients the diagnosis remained unclear. Using a cut-off of > or = 10(5) cfu/ml BAL fluid, sensitivity and specificity for the diagnosis of pneumonia were 33% (9/27) and 99% (132/133), respectively. Sensitivity was mainly influenced by prior treatment with antibiotics, being 70% (7/10) in untreated and 12% (2/17) in treated patients. Applying the BI methodology at a cut-off of > or =5, however, resulted in an unacceptably high rate of 16 additional false-positive results, thus lowering the specificity to 87% (116/133; P<0.0001) while increasing the sensitivity to only 41% (11/27; P = 0.77). In conclusion, given the high rate of false-positive results, the methodology of the BI is of doubtful value for the diagnosis of bacterial pneumonia by BAL in an unselected patient group. By applying the absolute number of cfu/ml BAL fluid, however, positive bacteriologic cultures of BAL fluid are highly specific for the diagnosis of pneumonia. Their sensitivity is limited by previous antibiotic therapy.

Molecular epidemiology of Mycobacterium tuberculosis strains isolated from patients in a human immunodeficiency virus cohort in Switzerland

From 1989 to 1995, 46 patients infected with the human immunodeficiency virus were diagnosed with tuberculosis at the University Hospital in Zurich. Using the IS6110 insertion sequence as a genetic marker, restriction fragment length polymorphism analyses were done for 52 Mycobacterium tuberculosis isolates. We have found a large degree of IS6110 polymorphism, ranging from 1 to 16 copies. For isolates from patients from whom multiple isolates had been available, the IS6110 pattern remained virtually stable over a period of up to 4 years, as well as during emerging drug resistance. In none of the cases was a reinfection of a patient with another strain detected. For isolates from 10 patients we detected identical patterns which could be associated with four clusters. In one of these, the strains exhibited a low IS6110 copy number (four bands), and the strains were further analyzed by hybridizing with (i) the polymorphic GC-rich repetitive sequence (PGRS) and (ii) the 36-bp direct-repeat (DR) cluster sequence. One of these isolates had a different pattern with the PGRS as well as with the DR sequence and could therefore be safely excluded from that cluster. These findings point to the importance of applying more than one genetic criterion in the molecular biological study of strain relatedness.

In vitro activity of cefpirome against microorganisms isolated in haematology, oncology and intensive care units in Switzerland

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.

[Tips and requests by microbiologists]

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.

Prospective evaluation of a semiquantitative dip slide method compared with quantitative bacterial cultures of BAL fluid

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.

[Effectiveness of triple therapy to eradicate H. pylori in patients after failed therapy with omeprazole/amoxicillin]

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.

Antimicrobial susceptibilities and serotypes of invasive Streptococcus pneumoniae strains in Switzerland

In 1993 and 1994, 10 microbiological laboratories in Switzerland collected 351 strains of Streptococcus pneumoniae from invasive infections. Susceptibilities to the main representatives of the chemical classes were as follows: penicillin, 93%; chloramphenicol, 92%; erythromycin, 94%; sulfamethoxazole-trimethoprim, 86%; tetracycline, 92%; vancomycin, 100%. Forty-three strains showed resistance to one agent, and 35 strains showed resistance to two or more antimicrobial agents simultaneously; i.e., 22% of the strains were resistant to at least one antimicrobial agent. Four strains (1%) were fully resistant to penicillin, whereas 21 strains (6%) showed reduced susceptibility. Of these 25 strains not fully susceptible to penicillin, 10 were resistant to one, 3 were resistant to two, and 8 were resistant to three additional antimicrobial agents. Of the quinolones, sparfloxacin was the most active substance, with an MIC at which 90% of the strains are inhibited of 0.5 mg/liter. The most common serotypes were types 6 (13.6% of isolates), 7 (10.5%), 19 (10.5%), 14 (9.1%), and 1 (8.5%) as well as 3 and 23 (8.0% each). Reduced susceptibility to penicillin was found mainly among serotypes 6, 14, 19, and 23. The currently available 23-valent pneumococcal vaccine covers 320 (91%) of the pneumococci isolated. Regional differences within Switzerland with regard to serotypes and antimicrobial resistance were not observed.

Soft tissue infections of the upper extremities with special consideration of abscesses in parenteral drug abusers. A prospective study

Despite surgical advances and new antibiotics, upper extremity infections continue to present a serious problem. Soft tissue infections of the upper extremities were prospectively examined to elucidate incidence, cause, bacterial pathogens involved, and treatment. Special attention was paid to infections associated with parenteral drug abuse. During an 18-month period all patients over 16 years of age presenting for treatment of an established infection were included in the study. Conservative treatment consisted of immobilization and antibiotics. Radical débridement with removal of all necrotic tissue was the guideline for operative care. In addition, for both regimens a penicillinase-resistant antibiotic was administered. A total of 415 patients (271 men and 144 women; mean age 36.7 +/- 14.5 years) were enrolled into the study, 55 of whom were parenteral drug abusers; 45 of these were HIV-reactive. Infections of fingers (excluding paronychia), paronychia and abscesses at injection sites were the most common diagnoses. Operative and conservative treatment were performed in 285 and 130 patients respectively. Staphylococcus and streptococcus species were the predominant organisms recovered from 212 specimens of pus. Anaerobic bacteria and yeasts were of minor importance. Therefore, a penicillinase-resistant antibiotic is a good initial choice.

Comparison of BacT/Alert blood culture bottles with lytic media for culture of peritoneal dialysis fluid

A comparison was made between the Septi-Chek "Release" system containing saponins, standard BacT/Alert blood culture bottles and FAN BacT/Alert blood culture bottles for culturing CAPD fluids. Seventy-seven CAPD effluent specimens were tested. No differences could be found. Therefore, lytic agents are not necessary when dialysates are cultured in blood culture media.

Assignment of Actinomyces pyogenes-like (CDC coryneform group E) bacteria to the genus Actinomyces as Actinomyces radingae sp. nov. and Actinomyces turicensis sp. nov

In a previous study the authors reported the characterization of some facultatively anaerobic, Gram-positive, non-sporeforming rods which were found in mixed cultures from various infectious processes, including patients with otitis, empyema, perianal abscesses and decubitus ulcers. Phenotypically these organisms closely resembled Actinomyces pyogenes although their precise taxonomic position remained unknown. In the present investigation the authors have determined the 16S rRNA gene sequences of some representative strains of the Actinomyces pyogenes-like bacteria and report the results of a comparative sequence analysis. On the basis of the results of the present and earlier findings two new Actinomyces species, Actinomyces radingae sp. nov. and Actinomyces turicensis sp. nov. are proposed. The type strains are DSM 9169T and DSM 9168T, respectively.

[sensitivity of bacteria to chemotherapeutic agents (Zurich, 1993)]

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.

Analysis of restriction fragment length polymorphism and ribotyping of multiresistant Stenotrophomonas maltophilia isolated from persisting lung infection in a cystic fibrosis patient

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.

Propionibacterium acnes as a cause of aggressive aortic valve endocarditis and importance of tissue grinding: case report and review

A case of prosthetic valve endocarditis with Propionibacterium acnes is described. The diagnosis was documented by histology and isolation of P. acnes from both blood and anulus tissue. Grinding of the tissue, which was first omitted to avoid contamination, was indispensable for cultivating the agent. The literature for P. acnes endocarditis is reviewed.

[Antibiotic sensitivity of gram-negative bacteria in intensive care units in Switzerland]

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.

[Multicenter evaluation of oral antibiotics: resistance behavior in 5 Swiss centers]

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.

[Omeprazole/amoxicillin: improved eradication of Helicobacter pylori in smokers because of N-acetylcysteine]

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)

[Omeprazole/amoxicillin: impaired eradication of Helicobacter pylori in smoking but not in premedication with omeprazole]

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)

[Eradication of metronidazole-resistant Helicobacter pylori: is omeprazole/amoxicillin a therapeutic alternative?]

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 role of two-segment bronchoalveolar lavage in the diagnosis of pulmonary infections

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 vitro activity of ceftriaxone combined with tazobactam against anaerobic bacteria

The in vitro activity of ceftriaxone combined with tazobactam against 190 strains of anaerobic bacteria was compared with that of amoxicillin with clavulanic acid, ampicillin with sulbactam, piperacillin alone and with tazobactam, cefoxitin, and imipenem, i.e. beta-lactam antibiotics established in the treatment of anaerobic infections. All anaerobes tested were susceptible to < or = mg/l ceftriaxone when tazobactam was added at fixed ratios (ceftriaxone to tazobactam) of 2:1 and 8:1 and at constant concentrations of 2,4 and 8 mg/l, respectively. When 4 mg/l tazobactam was added, the MICs of ceftriaxone for 83 of 94 strains of the Bacteroides fragilis group were reduced by a factor of 8 to 512; for eight strains, this reduction was two to fourfold. Only the MICs of ceftriaxone for three Bacteroides fragilis strains were not influenced.

[A trial of modified triple therapy for the eradication of H. pylori in recurrent duodenal ulcer]

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)

Penetration of clarithromycin into human saliva

The concentrations of clarithromycin after a single oral dose of 500 mg were determined in serum and saliva of ten healthy adult volunteers. After 2 h, the levels were 4.04 +/- 1.14 (SD) mg/l in serum and 2.72 +/- 0.87 mg/l in saliva. After 7 h these values were 1.98 +/- 0.65 and 1.21 +/- 0.34 mg/l, respectively, and at the end of the dosing interval of 12 h, 0.95 +/- 0.38 and 0.73 +/- 0.35 mg/l, respectively. In comparison, amoxicillin (a 750-mg single dose) showed a much faster decline of serum levels and was virtually undetectable in saliva.

[Community-acquired Acinetobacter pneumonia]

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.

Isolation of gram-positive rods that resemble but are clearly distinct from Actinomyces pyogenes from mixed wound infections

Beginning in 1990, gram-positive rods resembling Actinomyces pyogenes were found with increasing frequency in mixed cultures from various infectious processes, most of them from patients with otitis, empyema, pilonidal cysts, perianal abscesses, and decubitus ulcers. Ribotyping and hybridization showed that these gram-positive rods could be divided into five groups not related to known Actinomyces species. Biochemical markers for reliable differentiation into these groups, however, could not be found. Therefore, naming new species is not warranted unless parameters are discovered that allow identification without DNA hybridization. These gram-positive rods have been isolated only in mixed cultures with anaerobes, Staphylococcus aureus, Streptococcus "milleri," enterococci, and gram-negative rods. Their exact role in these possibly synergistic infections needs further investigation.

Evaluation of two enzyme immunoassays for rapid detection of group B streptococci in pregnant women

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.

Comparison of the E test and a reference agar dilution method for susceptibility testing of anaerobic bacteria

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%.

Comparative in vitro activity of Ro 40-6890, Ro 41-3399, and other antimicrobial agents against anaerobic bacteria

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.

[The sensitivity of anaerobic bacteria to chemotherapeutic agents (Zurich, 1991)]

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.

[Actinomycosis--clinical and therapeutic considerations based on 2 personal case reports]

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)

[Bacterial sensitivity to chemotherapeutic agents (Zurich, 1990)]

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.

[Micrococcus luteus: a rare pathogen of valve prosthesis endocarditis]

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.

Interpretive criteria for disk diffusion susceptibility testing of sparfloxacin

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).

[The problems of rapid diagnosis of Clostridium difficile as causative agent of antibiotic-associated pseudomembranous colitis]

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.

Multilaboratory evaluation of an agar diffusion disk susceptibility test for rapidly growing anaerobic bacteria

A multilaboratory collaborative study was undertaken to determine whether the anaerobic disk diffusion test of Horn et al. could be performed reproducibly and accurately. Tests with nine different antimicrobial disks were evaluated. Reproducibility of the agar diffusion disk method was similar to that of the reference agar dilution test procedure. The anaerobic disk diffusion procedure was found to be a potentially useful method for testing some antimicrobial agents against rapidly growing anaerobes belonging to the Bacteroides fragilis group. These promising results warrant further investigations and validations.

Clinical efficacy of amoxycillin/clavulanate in laparoscopically confirmed salpingitis

To test the efficacy and safety of amoxycillin/clavulanate (Augmentin), 102 hospital patients with laparoscopically confirmed acute salpingitis were treated with parenteral amoxycillin/clavulanate (1.2 g qid for three days) followed by oral amoxycillin/clavulanate (two tablets of 625 mg tid for a further six days). Bacteriological samples were obtained from the cervix uteri and the pouch of Douglas. One hundred patients were assessable for clinical outcome using several variables including pain scores. Amoxycillin/clavulanate alone was effective in 95 patients (95%). Three patients (3%) responded to amoxycillin/clavulanate with marked improvement but another antibiotic was subsequently added to their treatment regimen. Treatment failed in two patients. At follow-up two weeks after hospital discharge, three patients (3.8%) had relapsed or were re-infected. Adverse drug events included one case of drug fever, one case of rash and one case of severe diarrhoea. Treatment was stopped in all three cases. Gastrointestinal reactions, mainly mild diarrhoea, were seen in 31 patients. No clinically relevant changes in haematological or clinical chemical indices were attributable to the amoxycillin/clavulanate treatment. We conclude that amoxycillin/clavulanate is a clinically effective and safe treatment for acute salpingitis.

[Bacterial susceptibility to chemotherapeutic agents (Zurich, 1987)]

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".

Food-borne botulism: an uncommon disorder

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.