Pseudomonas aeruginosa in French hospitals between 2001 and 2011: back to susceptibility.

The European Antimicrobial Resistance Surveillance Network (EARS-Net) reported an increase in the rates of resistance of Pseudomonas aeruginosa to antimicrobials between 2008 and 2011 in France. This alarming report was based on data collected during the harmonisation of breakpoints by the European Committee on Antimicrobial Susceptibility Testing (EUCAST) committee. However, these data were not supported by the findings of other national surveillance networks. In this study, we assessed the trends in P. aeruginosa antimicrobial drug resistance at six French hospitals over a longer period of time (2001-2011) and with a constant definition of resistance. After the exclusion of incomplete data and duplicates, we sorted 34,065 isolates into the antimicrobial resistance patterns defined by the European Centre for Disease Prevention and Control (ECDC). The proportion of isolates with a resistant pattern (non-susceptible to one or two antimicrobial categories), a multidrug-resistant pattern (non-susceptible to three or four antimicrobial categories) or an extensively drug-resistant pattern (non-susceptible to five or six antimicrobial categories) decreased significantly over time. Logically, the proportion of isolates with a wild-type resistance pattern has increased significantly over the same period. No significant changes in the rates of resistance to cephalosporins and penicillins were observed, whereas carbapenem resistance rates increased. By contrast, the proportion of isolates resistant to fluoroquinolones, aminoglycosides and monobactams decreased significantly over time. In conclusion, our data do not confirm the EARS-net data, suggesting instead that antimicrobial drug resistance in P. aeruginosa might not have increased in French hospitals over the last decade.

[Culture and susceptibility testing of mycobacteria with VersaTREK]. / La culture et l'antibiogramme de mycobactéries sur automate VersaTREK.

OBJECTIVES: Our laboratory of microbiology use the VersaTREK/ESP Culture System II for the isolation of mycobacteria. In this study, we evaluate this system for the analysis carried out between April 2009 and March 2010. METHOD: The Myco bottles are supplemented with growth supplements and an antimicrobial agent solution prior to inoculation with the specimen. The technology of the VersaTREK/ESP Culture System II is based on the detection of headspace pressure changes within a sealed bottle. It monitors changes in either gas production or gas consumption due to microbial growth. A special algorithm has been developed for detection of very slow growing mycobacteria. The bottles are incubated during 42 days. Meanwhile a solid medium is inoculated too. All specimen types can be analysed with this system. RESULTS: Compared to solid culture, the time needed for detection of positive cultures was significantly shorter for the VersaTREK with a good recovery rate. For isolates recovered in both systems, mean time of detection is respectively 19.1 and 35.6 days for liquid and solid cultures. Mycobacteria identification may be determined using nucleic acid probs directly in Myco VersaTREK or in the solid medium. The susceptibility test of Mycobacteria tuberculosis complex is obtained between six and 13 days for rifampin, isoniazid, ethambutol, streptomycin and pyrasinamide. CONCLUSION: This system offers a faster diagnosis and is an alternative to other instruments using liquid culture.

[The use in routine of mass spectrometry in a hospital microbiology laboratory]. / Bilan de l'utilisation en routine de la spectrométrie de masse dans un laboratoire hospitalier de microbiologie.

OBJECTIVES: Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has recently been introduced in diagnostic microbiology laboratories for the identification of microorganisms. The mass fingerprint obtained by analyzing the ribosomal proteins and proteins associated with membranes is compared to spectra and superspectra of database. Microbiological Laboratory of Mulhouse acquired this system 1 year ago. METHOD: The MALDI-TOF MS analyses of all strains were performed on Axima(®) (Shimadzu), data analysis with Saramis(®) software (Anagnostec) and integration with SirWeb(®) software (I2A society). RESULTS: Rapidly, laboratory technicians and biologists are able to turn the system after a few days of training. The data prospectively gathered in the present study demonstrated that MALDI-TOF mass spectrometry identification is an efficient method included fastidious bacteria. Exactly 98.8 % of 10,000 isolates were identified in genus and species levels. Use of identification techniques was seldom necessary for a few clinical relevant isolates. The database is in constant evolution. The superspectra contain characteristic signals of genus, species allowing reliable microorganism identifications with high confidence. CONCLUSION: In conclusion, our results show that MALDI-TOF MS is a fast and reliable technique for identification of most bacterial strains routinely isolated in a clinical microbiology. Identification and susceptibility testing with a single cell colony are more often possible. The simple tests, such as Gram staining and oxidase and catalase tests are usually performed in our laboratory.

Human babesiosis in Alsace.

OBJECTIVES: Human babesiosis is a rare parasitic anthropozoonosis transmitted to humans by tick bites. Fifty-six cases of human babesiosis have been recorded in Europe. Two cases of babesiosis were reported in Alsace, France, in 2009. We performed a retrospective observational descriptive study to assess the epidemiology of the disease in Alsace. METHODS: Patients were included if they had a positive serology result for Babesia and/or a positive blood smear and/or a positive PCR result. The tests were performed in the microbiology laboratories of the university hospitals of Strasbourg, the civil hospitals of Colmar, and the hospital of Mulhouse between January 1, 2005 and December 31, 2015. Included patients were divided into three groups: definite case group (positive PCR or positive blood smear or seroconversion), possible case group (positive serology results without seroconversion with a compatible clinical picture and without other confirmed diagnoses), and incompatible case group (positive serology results without seroconversion, without compatible clinical picture and/or with other confirmed diagnoses). The compatible clinical picture was defined by the presence of flu-like symptoms and fever (≥38°C). RESULTS: Fifty-one patients had at least one positive result. Three cases were excluded (missing files). There were six definite cases, 12 possible cases, and 30 incompatible cases. All patients in the definite case group were immunocompetent. No deaths occurred. CONCLUSIONS: Human babesiosis is probably underdiagnosed due to its non-specific symptoms, lack of awareness about the disease, and the difficulty in making a diagnosis.

Stenotrophomonas maltophilia healthcare-associated infections: identification of two main pathogenic genetic backgrounds.

BACKGROUND: Stenotrophomonas maltophilia is an opportunistic multi-drug-resistant bacterium responsible for healthcare-associated infections. Strategies for in-hospital infection control and management of carriers and environmental reservoirs remain controversial. AIM: To determine the population structure of S. maltophilia strains in hospitalized infected patients and to identify putative highly pathogenic subpopulations that require upgraded infection control measures. METHODS: Eighty-three diverse human strains of various clinical origins from 18 geographically distant hospitals were characterized phenotypically and genotypically using a multi-locus sequence typing (MLST) approach. FINDINGS: Neither a predominant nor emerging sequence type (ST) was identified. Among the 80 typeable strains, only 29% corresponded to described STs, especially ST5 (N=6) and ST4/26/31 (N=2). The ST distribution and the phylogenic tree based on the concatenated MLST genes did not account for geographical, clinical origin or antimicrobial susceptibility clustering. A phylogenic tree that included 173 ST profiles from the MLST database and the 80 typeable strains confirmed the high genetic diversity of S. maltophilia, the previously reported genogroup organization and the predominance of genogroup 6, as it represented 41% (33/80) of the strains. Unexpectedly, genogroup 2 was the second most prevalent genogroup and included 16% (13/80) of the strains. These genogroups represented 57% (20/35) of the strains in respiratory patients and 75% (9/12) of the strains in patients with cystic fibrosis. CONCLUSION: Beyond MLST, the over-representation of some genogroups among strains responsible for healthcare-associated infections was confirmed. Genogrouping affiliation is recommended to implement infection control measures selectively for the most pathogenic strains isolated from patient or environmental reservoirs.

Changes in microbial ecology and use of cloxacillin.

There is generally a positive correlation between antibiotic consumption and incidence of resistance to antibiotics used either for prophylaxis or therapy in human infections. This was not the case for two surgical wards in our hospital. A 15-year study showed that the incidence of methicillin-resistant Staphylococcus aureus (MRSA) was unrelated to cloxacillin consumption, and in fact fell after introduction into the two wards of an antibiotic policy based on cloxacillin. The two wards, a 90-bed orthopaedic unit and a 60-bed trauma unit, had an incidence of MRSA that has remained below the hospital average (23% in 1989, 32% in 1992). Before introduction of the policy the incidence of MRSA in 1977-1979 in the orthopaedic ward was 31%, and in the trauma ward 33%. In 1989 an investigation revealed no MRSA carriers in staff of either ward. In contrast, seven MRSA carriers were found among staff and patients of three other surgical units selected, because the percentage of MRSA isolated was above the average in our hospital. However, a different type of patient is found in these units, the treatment techniques differ and broader-spectrum antibiotics are used. In addition to the usual precautions regarding nursing care and isolation techniques, the best means of reducing MRSA epidemics is to reduce the reservoir of carriers. The fall in the MRSA infection rate in orthopaedic and traumatology wards can be explained by antibiotic policy but also by other infection control measures.

The origin of adaptation and dyssymmetry in the evolution of autocatalytic systems.

The evolution of open systems that include several autocatalytic processes in parallel or in series is mathematically analyzed. For the case of two reactions in parallel, such systems progressively and finally select the reaction pathway which involves the better autocatalyst. The effect of parameters influencing the rate of this evolution is discussed. Where catalysts are strictly equivalent, e.g. enantiomers in a symmetrical surrounding, the evolution is amplified by fluctuations and retains finally only one reaction pathway, if the autocatalytic rates of reactions are more than proportional to the catalyst concentrations. When including two reactions in series, these open systems are also able to give oscillations.

[Actinomyces meyeri cutaneous actinomycosis with pulmonary localization]. / Actinomycose cutanée à Actinomyces meyeri avec une localisation pulmonaire.

Infections due to Actinomycosis species are located in the cervico-facial region in 50 to 65 percent of the cases. Extra-cervical cutaneous lesions are exceptional. The most frequently encountered germ is Actinomyces israeli, observed in 85 percent of the cases. We report the case of an Actinomyces meyeri infection which presented as a leg abscess and a pulmonary lesion. There was no cervico-facial localization. There was however a chronic parodontitis. A second germ, Capnocytophaga sp. was isolated from the abscess. This case is of particular interest because of the extracervical localization and the rare species isolated (17 other cases of Actinomyces meyeri infection have been reported). The mechanism of the infection can be better understood in light of pulmonary lesions in the lower right lobe due to inhalation and the coexistence of a buccodental germ in the culture of the leg abscess: buccodental origin of the germ, pulmonary lesion secondary to inhalation, septicaemic dissemination with cutaneous metastases.

[Evolution of antibiotic resistance of Streptococcus pneumoniae: results of Alsace observatory in 2005]. / Evolution de la sensibilité de Streptococcus pneumoniae aux antibiotiques: résultats de l'observatoire du pneumocoque Alsace (année 2005).

OBJECTIVES: Between 1st January 2005 and 31st December 2005, 232 strains of Streptococcus pneumoniae were collected in the Alsace county from participating laboratories (one from university hospital, 7 from general hospitals and 12 private laboratories) to assess their susceptibility to penicillin and evaluated serogroups of strains. METHOD: The coordinating centre performed MICs by the reference agar dilution test, interpreted according to CA-SFM breakpoints. Others antibiotics (erythromycin, cotrimoxazole, tetracycline...) were tested by agar diffusion, ATB-PNEUMO gallery or VITEK gallery (BioMérieux, France) by each participating laboratory. Data were processed, using 4th dimension software. RESULTS: Strains were collected from 151 blood samples, 38 ear pus, 11 cerebrospinal fluids, 8 pleural liquids and 24 representative pulmonary samples. The prevalence of pneumococci with decreased susceptibility to penicillin G (PDSP) is 35.1% (pulmonary samples excluded). The rate of PNSP decreases for all types of samples compared with other years of surveillance 2003 (44.0%). The rate of blood samples decreases for first time between the creation of Pneumococcal Observatory. The high-level resistance tend to decrease and began low. The PDSP are rather resistant to erythromycin, cotrimoxazole and fosfomycin. Among the PDSP, the most prevalent serotypes were 14, 19, 6 and 9. CONCLUSION: Among pneumococcal strains, the rate of PDSP tend however to decrease in 2005 compared with 2003. The rate stays inferior to the observed rates in other French counties where the same decreasing is described.

In vitro activity of teicoplanin against gram-positive cocci.

The glycopeptide susceptibility of 443 clinical isolates of gram-positive cocci collected from nine general hospitals in 1996 was determined according to the recommendations of the CA-SFM (the Antibiogram Committee of the French Society for Microbiology). In total, 234 isolates of Staphylococcus aureus, 84 isolates of coagulase-negative staphylococci (CNS), 98 enterococci and 27 streptococci were collected. The mecA gene confirming resistance to methicillin was found in 42.7% of S. aureus isolates and 51.2% of CNS isolates. No resistance to teicoplanin and vancomycin was found in S. aureus but four isolates of CNS had an MIC of teicoplanin > or = 8 mg/L. All isolates of Enterococcus faecalis tested were susceptible to both glycopeptides. This study confirms that teicoplanin has a very good in vitro activity against gram-positive cocci, isolated in France from nosocomial infections.