Actinobaculum schaalii: clinical observation of 20 cases.

Actinobaculum schaalii is a new species that has so far been isolated from human blood, urine and pus. Its importance has probably been underestimated and other Actinobaculum spp. may also have been underdiagnosed. This retrospective study comprises all known cases of A. schaalii infections identified since 2004 in the canton of Neuchâtel (170,000 inhabitants), Switzerland. Strains were cultivated and isolated in the bacteriology laboratory using its routine procedure. Identification included a Rapid ID 32 A strip (bioMérieux) and 16S rRNA gene sequencing. Twenty-one positive samples were found in 19 patients (11 male, 8 female) of all ages (range 16-91 years): 10 from urine (50%), six from blood (30%), one from both blood and urine (5%), and three from pus (15%). Thirteen out of 17 (76%) cases with either blood or urine specimens had underlying genitourinary tract pathologies. When urine cultures were positive for A. schaalii, leucocytes were found in all samples (10/10, 100%) but all nitrite tests were negative (10/10, 100%). The onset of appropriate treatment was delayed due to the diminished sensitivity of A. schaalii to the antibiotics commonly used for UTIs (i.e. ciprofloxacin and trimethoprim/sulfamethoxazole) and to the delay in microbiological diagnosis. A. schaalii should specifically be searched in all cases of leukocyturia with a negative nitrite test but with Gram-positive rods in the Gram stain, in patients with underlying genitourinary tract pathology, instead of dismissing these findings as clinically irrelevant colonization by coryneform bacteria. This infection may be much more common than previously thought.

Changing molecular epidemiology of methicillin-resistant Staphylococcus aureus in a small geographic area over an eight-year period.

The epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) at an international level shows that most MRSA strains belong to a few pandemic clones. At the local level, a predominance of one or two clones was generally reported. However, the situation is evolving and new clones are emerging worldwide, some of them with specific biological characteristics, such as the presence of Panton-Valentine leucocidin (PVL). Understanding these changes at the local and international levels is of great importance. Our objective was to analyze the evolution of MRSA epidemiology at multiple sites on a local level (Western Switzerland) over a period of 8 years. Data were based on MRSA reports from seven sentinel laboratories and infection control programs covering different areas. Pulsed-field gel electrophoresis was used to type MRSA isolates. From 1997 to 2004, a total of 2,256 patients with MRSA were reported. Results showed the presence of four predominant clones (accounting for 86% of patients), which could be related to known international clones (Berlin, New York/Japan, Southern Germany, and Iberian clones). Within the small geographic region, the 8-year follow-up period in the different areas showed spacio-temporal differences in the relative proportions of the four clones. Other international MRSA clones, as well as clones showing genetic characteristics identical to those of community-acquired MRSA (SCCmec type IV and the presence of PVL genes), were also identified but presumably did not disseminate. Despite the worldwide predominance of a few MRSA clones, our data showed that at a local level, the epidemiology of MRSA might be different from one hospital to another. Moreover, MRSA clones were replaced by other emerging clones, suggesting a rapid change.

Outbreak of human listeriosis associated with tomme cheese in northwest Switzerland, 2005.

During an eight week period in spring 2005, 10 cases of listeriosis were reported in a small area of northwest Switzerland (150,000 inhabitants). Eight cases were in older immunocompromised patients who became ill with bacteraemia (three deaths), and two cases were in pregnant women who had septic abortion. All cases were due to a serotype 1/2a isolate with one of two pulsovars found by PFGE. Patient interviews quickly revealed that a locally made and distributed soft cheese (known as 'tomme') was the food source responsible for the outbreak. Samples of this cheese, and of butter made in the same factory, revealed Listeria monocytogenes sv 1/2a of the same pulsovar in amounts of 1000-10 000 and 10-100 cfu/g, respectively. The prompt suspension of production, the market recall of the product, and a public alert terminated the outbreak. However, two cases of febrile gastroenteritis due to the same strains were reported within 10 days of product recall. The restricted distribution area of the contaminated cheese and the collaboration of local physicians, medical microbiologists and food health services all contributed to a rapid and successful investigation. This small outbreak of listeriosis reinforces the need for a laboratory-based surveillance system with rapid typing, as well as collaboration between physicians and microbiologists.

Outbreak of human listeriosis associated with tomme cheese in northwest Switzerland, 2005.

During an eight week period in spring 2005, 10 cases of listeriosis were reported in a small area of northwest Switzerland (150 000 inhabitants). Eight cases were in older immunocompromised patients who became ill with bacteraemia (three deaths), and two cases were in pregnant women who had septic abortion.

Treatment of secondary peritonitis: is a less expensive broad-spectrum antibiotic as effective as a carbapenem?

BACKGROUND: In this retrospective study, the possibility of using amoxicillin/clavulanate for empirical therapy of secondary peritonitis as an alternative to imipenem was explored. METHODS: All secondary peritonitis cases at our institution between 1998 and 2000 were included. Susceptibility to imipenem and amoxicillin/clavulanate of microorganisms isolated in peritoneal fluid and success rates were compared. Therapeutic failure was defined as death, necessity of repeated surgical intervention, or clinical deterioration with persistent positive cultures. RESULTS: Seventy-six cases of secondary peritonitis with 156 microorganisms were found. One hundred and forty-nine (98%) were susceptible to imipenem versus 124 (82%) to amoxicillin/clavulanate (p = 0.0001). Thirteen therapeutic failures occurred in 52 patients treated with amoxicillin/clavulanate (25%) versus 3 out of 8 (38%) with imipenem (p = 0.43). The proportion of organisms resistant to amoxicillin/clavulanate in therapeutic failures was greater in nosocomial versus community-acquired secondary peritonitis (p = 0.041). CONCLUSION: Despite its better in vitro bacteriological activity, clinical efficacy of imipenem was identical to amoxicillin/clavulanate. The use of amoxicillin/clavulanate instead of imipenem would save 889 Euro per case.

Frequency of Cryptosporidium spp. as cause of human gastrointestinal disease in Switzerland and possible sources of infection.

Detection of Cryptosporidium parvum is not routinely done in laboratories of clinical microbiology and there is no obligation to communicate isolations of this pathogen to health authorities. For these reasons, frequency of cryptosporidiosis and sources of infection are only poorly known in Switzerland. To obtain more concise information in this field, feces from 5179 hospitalized and 1256 ambulatory patients with suspected gastrointestinal infections were screened for Cryptosporidium spp. over the period of one year in two laboratories. In toto, 13 patients with cryptosporidiosis were detected which results a frequency of 0.2%. Furthermore, it was shown by a projection that about 340 cases of cryptosporidiosis have to expected yearly in Switzerland, resulting an estimated morbidity of 4.85 cases per 100,000 persons. With regard to risk factors, the available patient data did not allow solid statistical conclusions. However, known risk factors such as immunosuppression, travelling abroad (33.3%) and contact to symptomatic persons were unquestionably demonstrated. Oysters, raw milk and cream from raw milk had to be strongly taken into consideration as food vehicles of transmission. Tap water from municipal nets has not to be considered as relevant source of sporadic infections. The obtained data indicate that cryptosporidiosis is a disease of low epidemiological significance in Switzerland. To a great extent, cryptosporidiosis could be prevented by best known measures of personal hygiene, avoiding certain raw food-stuffs and being aware of safe catering on travels.

The effect of intra-gastric acidity and flora on the concentration of N-nitroso compounds in the stomach.

BACKGROUND: Correa's hypothesis proposes that gastric carcinogenesis is due to atrophic gastritis and hypochlorhydria which permit gastric bacterial colonization, the reduction of dietary nitrates to nitrites and the formation of potentially carcinogenic N-nitroso compounds (NOCs). OBJECTIVE: To test the hypothesis that omeprazole-induced hypochlorhydria is associated with increased intra-gastric concentrations of nitrate-reducing bacteria (NRB), nitrites and NOCs. DESIGN: Single-blind study in healthy volunteers. PARTICIPANTS: Fourteen healthy subjects (seven female, mean age 24 years), free of Helicobacter pylori infection, received a one-week course of placebo followed by a two-week course of omeprazole, 20 mg daily. METHODS: Fasted gastric samples, aspirated using a sterile double-lumen nasogastric tube at the end of the 1 st week (placebo) and the 2nd and 3rd weeks (omeprazole), were cultured aerobically and anaerobically; gastric pH and intra-gastric concentrations of nitrates, nitrites and NOCs were also determined. RESULTS: After weeks 1, 2 and 3, the intra-gastric concentrations of nitrate-reducing bacteria exceeded 10(5) colony-forming units (c.f.u.)/ml in 3, 7 and 9 subjects, respectively (P > 0.05). A gastric pH greater than 4.0 was associated with increased NRB (P < 0.05); however, neither increased gastric pH nor increased NRB, alone or in combination, was associated with increased intra-gastric concentrations of nitrites or NOCs (P > 0.05). CONCLUSIONS: A two-week increase in gastric pH in healthy, H. pylori-negative subjects was associated with increased intra-gastric concentrations of nitrate-reducing bacteria but not of nitrites or N-nitroso compounds. These data suggest that reduced gastric acid secretion is not a necessary precursor to the formation of carcinogenic N-nitroso compounds and that other mechanisms should be invoked to explain gastric carcinogenesis.

Molecular identification and epidemiological tracing of Pasteurella multocida meningitis in a baby.

We report a case of Pasteurella multocida meningitis in a 1-month-old baby exposed to close contact with two dogs and a cat but without any known history of injury by these animals. 16S rRNA gene sequencing of the isolate from the baby allowed identification at the subspecies level and pointed to the cat as a possible source of infection. Molecular typing of Pasteurella isolates from the animals, from the baby, and from unrelated animals clearly confirmed that the cat harbored the same P. multocida subsp. septica strain on its tonsils as the one isolated from the cerebrospinal fluid of the baby. This case stresses the necessity of informing susceptible hosts at risk of contracting zoonotic agents about some basic hygiene rules when keeping pets. In addition, this study illustrates the usefulness of molecular methods for identification and epidemiological tracing of Pasteurella isolates.

Susceptibility to levofloxacin of clinical isolates of bacteria from intensive care and haematology/oncology patients in Switzerland: a multicentre study.

The objective of this study was to examine the susceptibility of clinical isolates to levofloxacin, a fluoroquinolone with extended activity against Gram-positive bacteria, and other antibiotics in 12 Swiss clinical microbiology laboratories using the NCCLS disc diffusion technique. Isolates were prospectively collected from intensive care units (ICUs (59%), oncology wards (7%) and other units with haematology/oncology patients (34%) from June 1995 to March 1996. The levofloxacin breakpoints used were as recommended by the manufacturer. A total of 310 Gram-positive and 580 Gram-negative isolates from the respiratory tract (36%), skin/wounds (12%), blood (16%), urine (17%) and other sources (19%) were tested. The percentage of isolates susceptible to levofloxacin was 100% for Enterococcus spp. (38 strains), Streptococcus agalactiae (13), Streptococcus pneumoniae (65), Acinetobacter spp. (11), Citrobacter diversus (6), Citrobacter freundii (17), Klebsiella oxytoca (39), Morganella morganii (16), Proteus mirabilis (20), Proteus vulgaris (23), Serratia spp. (19), Stenotrophomonas maltophilia (10) and Haemophilus influenzae (41). The percentage of isolates susceptible to levofloxacin for Staphylococcus aureus (95 strains, including 2% MRSA) was 94%, coagulase-negative staphylococci (85) 65%, Enterobacter spp. (75) 99%, Escherichia coli (111) 97%, Klebsiella pneumoniae (45) 98% and Pseudomonas aeruginosa (124) 87%. In conclusion, levofloxacin is a new fluoroquinolone to which the most common clinical isolates in Switzerland are susceptible. The susceptibility of Enterococcus spp. and S. pneumoniae to levofloxacin was particularly remarkable. This compound appears to be a promising therapeutic alternative for the treatment of Gram-positive infections.

Clarithromycin versus amoxicillin-clavulanic acid in the treatment of community-acquired pneumonia.

In an open, prospective, randomised study, the clinical and bacteriological efficacy of intravenously administered clarithromycin was compared with that of amoxicillin-clavulanic acid in 112 patients with community-acquired pneumonia requiring hospitalisation. Clinical cure or improvement occurred in 86% (48/56) of the clarithromycin-treated patients and 84% (47/56) of the amoxicillin-clavulanic acid-treated patients. The rate of bacteriologic eradication was similar for the two drugs as were the rapidity of a clinical response and the rate of improvement of radiological signs. Clarithromycin had a slightly higher rate of side-effects mainly due to phlebitis caused by the intravenous treatment, but treatment could be continued in all cases. Clarithromycin should be used with caution in patients being treated with digoxin because of a significant risk of bradycardia resulting from drug interaction.

[Level of stethoscope contamination in the hospital environment]. / Taux de contamination des stéthoscopes en milieu hospitalier.

The aim of this study was to determine the extent of the contamination of stethoscopes and their possible role in transmission of microorganisms. The stethoscopes of the medical doctors of the hospital of La Chaux-de-Fonds, Switzerland, were cultured and the date of the last cleaning recorded. 38 of the 62 stethoscopes surveyed were contaminated with microorganisms (61%). The majority of isolated organisms were gram-positive bacteria, primarily Staphylococcus species (89%). The cleaning of the stethoscopes was frequent for 32% of the doctors, rare for 46% and non-existent for 22%. After more than one day without cleaning of the stethoscope, the level of contamination rose from 0% to 69%. Stethoscope use may be an important factor in the spread of infectious agents, so that regular disinfection should be carried out (once a day at the very least).

Pasteurella multocida endocarditis: report of a case and review of the literature.

We report on a cirrhotic patient who presented with an aortic valve endocarditis due to Pasteurella multocida. This disease entity is rare and we take this opportunity to review the 6 cases published to date.

[Microbiological diagnosis in the clinical laboratory]. / Mikrobiologische Diagnostik im Praxislabor.

In general, microbiological diagnostic procedures in the practitioner's office are limited to direct detection of group A streptococci in throat swabs in patients with pharyngitis and to semiquantitative urine culture with Uricult or Urotube test kits in patients in whom urinary tract infection is suspected. Negative direct tests with throat swabs should be confirmed by culture in the clinical microbiology laboratory, as several test kits have only moderate sensitivity in detecting group-A beta-hemolytic streptococci and do not detect other groups of beta-hemolytic streptococci. The results of semiquantitative urine cultures should always be interpreted together with clinical data. Quality control procedures are necessary for the accurate performance of these tests, and an external quality assessment program will probably be introduced in the near future.

Quantitative antibiogram typing using inhibition zone diameters compared with ribotyping for epidemiological typing of methicillin-resistant Staphylococcus aureus.

Antibiogram typing of methicillin-resistant Staphylococcus aureus with selected antibiotics was evaluated as a primary epidemiological typing tool and compared with ribotyping. Antibiograms were derived with the Kirby-Bauer disk diffusion method by using erythromycin, clindamycin, cotrimoxazole, gentamicin, and ciprofloxacin. For typing, antibiogram data were analyzed by similarity analysis of disk zone diameters (quantitative antibiogram typing). One hundred seventy-two isolates were typed. Reproducibility reached 98% for the quantitative antibiogram and 100% for ribotyping. With three selected restriction enzymes (EcoRV, HindIII, and KpnI), 40 epidemiologically unrelated isolates could be classified into 21 ribotypes, whereas quantitative antibiogram typing classified these isolates into 19 groups. To evaluate the discriminatory power of the methods, we calculated an index of discrimination from data obtained with these 40 isolates. This index takes into consideration both the number of types defined by the typing method and their relative frequencies. With both ribotyping and quantitative antibiogram typing, high discrimination indices (0.972 and 0.954, respectively) were obtained. When epidemiological links between patients (ward, period of hospitalization, and contacts between staff and patients) were compared with the results of ribotyping or the quantitative antibiogram typing method, it appeared that both methods were able to discriminate epidemiological clusters, with only a few discrepancies. In conclusion, quantitative antibiogram typing, although not necessarily based on genomic markers, is a simple method which enables a reliable workup of methicillin-resistant S. aureus epidemic when sophisticated molecular typing methods are not available.

Effect of omeprazole on intragastric bacterial counts, nitrates, nitrites, and N-nitroso compounds.

Previous studies have suggested that profound inhibition of gastric acid secretion may increase exposure to potentially carcinogenic N-nitroso compounds. The aim of this study was to find out if the proton pump inhibitor omeprazole (20 mg daily) is associated with increased concentrations of potentially carcinogenic N-nitroso compounds in gastric juice. The volume of gastric contents, number of bacteria, and concentrations of nitrates, nitrites, and N-nitroso compounds was determined in gastric aspirates obtained after an overnight fast in 14 healthy volunteers (7M:7F) after one week of treatment with placebo, and one and two weeks' treatment with omeprazole. Median bacterial concentrations were 1.0 x 10(4) (range 5.0 x 10(3)-5.0 x 10(6)) colony forming units (CFU)/ml after one weeks' treatment with placebo and increased significantly to 4.0 x 10(5) (0-3.3 x 10(7)) CFU/ml after two weeks' treatment with omeprazole (p < 0.05). A similar increase was seen in the concentration of nitrate reducing bacteria. There was no difference in the volume of gastric aspirates after treatment with omeprazole when compared with placebo (65 (29-155) ml v 42 (19-194) ml). The concentration of N-nitroso compounds was 0.13 (0-1.0) mumol/l after two weeks of omeprazole, which was not significantly different from that seen with placebo (0.15 (0-0.61) mumol/l). There was also no increase in the concentrations of nitrates or nitrites. It is concluded that omeprazole (20 mg once daily) for two weeks in healthy volunteers is associated with gastric bacterial proliferation but does not increase concentrations of N-nitroso compounds.

Ribotyping of Pseudomonas aeruginosa: discriminatory power and usefulness as a tool for epidemiological studies.

Restriction fragment length polymorphism of ribosomal DNA regions (ribotyping) of Pseudomonas aeruginosa was evaluated as a tool for epidemiological purposes. Fifty-five epidemiologically unrelated isolates from three geographic areas of Switzerland and 11 isolates obtained during an outbreak of P. aeruginosa infections in a burn unit were typed by this method. Typeability and reproducibility of the method reached 100%. With four selected restriction enzymes (BamHI, ClaI, EcoRI, and PstI), the 55 unrelated isolates could be classified into 33 ribotypes. To assess the value of this method for the interpretation of epidemiological data, we calculated an index of discrimination (ID) which takes into consideration both the number of types defined by the typing method and their relative frequencies. Our ribotyping system obtained a high ID of 0.958 with only four restriction enzymes, comparing well with other different typing schemes for which ID values could be calculated from published data. All clinical isolates of the outbreak belonged to the same ribotype, whereas environmental isolates, initially thought to be the source of the epidemic, belonged to a different ribotype. Thus, the typeability, reproducibility, and discriminatory power of our method as well as its value established in an epidemiological investigation were found to be appropriate for further epidemiological studies of P. aeruginosa.

[Swiss quality control in bacteriology and mycology 1989-1991]. / Die Schweizerische Qualitätskontrolle für Bakteriologie und Mykologie 1989-1991.

Since 1983 there has been a voluntary quality assessment scheme (QAS) for bacteriology and mycology laboratories in Switzerland directed by the Committee for Quality Control of the Swiss Society for Microbiology. For the first time, the results of this QAS for the period between 1989 and 1991 are made available to a wider public. During the period in question, a steadily increasing number of participants received three samples containing microorganisms four times a year for identification and susceptibility testing. A mean percentage value of a point rating, with a maximum of 12 points, was calculated every year for each laboratory. Values of < or = 75% were defined as insufficient. For a first evaluation, laboratories were assigned to the categories of cantonal (and university) laboratories (C/U), private laboratories (P), and hospital laboratories (H, in hospitals which are neither university nor other tertiary care centres). Significant differences were detected between C/U and P on the one hand and H on the other. As a rule, H obtained poorer results than the two categories, examined fewer specimens, and their percentage with results < or = 75% was significantly higher. The second evaluation classified laboratories according to their recognition by the Swiss Federal Department of Public Health (FDPH). For statistical reasons, H had to be grouped with C/U. Nevertheless, their share of non-recognized laboratories was exceedingly high (15 out of 17 participants in 1991). Recognized laboratories constantly showed a better performance than non-recognized laboratories, examined more specimens, and their number of laboratories obtaining results < or = 75% was much lower.(ABSTRACT TRUNCATED AT 250 WORDS)

[Pneumonia: etiologic diagnosis and therapy in general practice]. / Pneumonie: Atiologische Diagnose und Therapie in der Praxis.

The majority of community-acquired pneumonias are not hospitalized, have a good prognosis and a low mortality rate. In the nonimmunocompromised adult patient, pneumonias are caused by a broad array of microorganisms of which the so-called 'atypical' agents (mycoplasma, chlamydiae, viruses) are as frequently found as classical bacteria such as pneumococci and haemophilus. Generally, the mode of acquisition and the clinical picture will not allow to deduct the etiology with certainty, and the laboratory results are often nonconclusive (sputum examination) or delayed (serology). Empirical therapy should be initiated based on epidemiological grounds and on the characteristics of the patient. For patients without underlying conditions, immunosuppression or advanced age, a macrolide (erythromycin or a new macrolide) appears to constitute a good choice because of its broad spectrum of activity, comprising the classical bacterial agents of pneumonia, mycoplasma, chlamydiae, and legionella.