The impact of performing bacterial identification and antimicrobial susceptibility testing on bronchoalveolar fluid cultures 24 h a day in a microbiology laboratory.

We previously demonstrated the positive impact of performing bacterial identification and antimicrobial susceptibility testing (AST) after day hours (night service [NS]) for certain clinical samples on the treatment of infected patients. Our objective was to evaluate the impact of including positive bronchoalveolar lavage (BAL) cultures in our NS. Two major positive consequences were recorded: initiation of earlier appropriate treatment and earlier change to a reduced-spectrum but still effective regimen. Reductions in delay were defined as the differences between the hours actually spent and hours estimated as though laboratory tests had been performed in the absence of NS. Fifty BALs were included. The NS led to the implementation of earlier appropriate therapy in 10 cases (20%), to earlier de-escalation in 15 cases (30%), and to earlier appropriate therapy and de-escalation in 4 cases (8%). In conclusion, performing bacterial identification and AST for positive BAL after laboratory opening hours could be relevant.

First report of endocarditis caused by a Pseudoclavibacter species.

We describe the first case of Pseudoclavibacter species endocarditis in a 44-year-old patient. This genus, rarely isolated from humans, confirms here its role as a human pathogen.

Discordance in the minimal inhibitory concentrations of ertapenem for Enterobacter cloacae: Vitek 2 system versus Etest and agar dilution methods.

Our objective was to compare the ertapenem minimal inhibitory concentrations (MICs) for Enterobacter cloacae isolates categorized intermediate or resistant to ertapenem when measured with the Vitek 2 system, with the MICs for these isolates when measured by two methods performed in agar medium: the Etest and agar plate dilution method (APDM). Overall, 50 E. cloacae isolates were included in the study. The mean MIC of ertapenem was 2.92±1.77µg/ml according to the Vitek 2 system, 0.94±0.84µg/ml according to the Etest strips, and 0.93±0.62µg/ml according to the APDM. Furthermore, the MICs determined by the Vitek 2 system were higher than the MICs determined by the two other methods for 96% of strains. Lastly, according to the Etest strips and APDM, 42% of E. cloacae were susceptible to ertapenem. No carbapenemase was identified by the screening method used. Using the Vitek 2 system to determine ertapenem MICs for E. cloacae can have potential consequences in terms of additional carbapenemase-detecting tests and antimicrobial therapy. It would be interesting to determine if the Vitek 2 system is more effective for the detection of carbapenemase producers with low-level carbapenem resistance than the two methods performed in agar medium.

Mycobacterium malmoense: an underestimated nontuberculous mycobacterium.

We present a case report of Mycobacterium malmoense in a 53-year-old white man. The incidence of M. malmoense infections is a rare event compared with other nontuberculous mycobacteria, but it has increased since 1980, especially in northern Europe. Many patients have disposing underlying diseases. In most cases, it is a pulmonary infection. The most frequent used antibiotics are rifampicin (or rifabutin), ethambutol, and clarithromycin.

Aquatic insects as a vector for Mycobacterium ulcerans.

Mycobacterium ulcerans is an emerging environmental pathogen which causes chronic skin ulcers (i.e., Buruli ulcer) in otherwise healthy humans living in tropical countries, particularly those in Africa. In spite of epidemiological and PCR data linking M. ulcerans to water, the mode of transmission of this organism remains elusive. To determine the role of aquatic insects in the transmission of M. ulcerans, we have set up an experimental model with aquariums that mimic aquatic microenvironments. We report that M. ulcerans may be transmitted to laboratory mice by the bite of aquatic bugs (Naucoridae) that are infected with this organism. In addition, M. ulcerans appears to be localized exclusively within salivary glands of these insects, where it can both survive and multiply without causing any observable damage in the insect tissues. Subsequently, we isolated M. ulcerans from wild aquatic insects collected from a zone in the Daloa region of Ivory Coast where Buruli ulcer is endemic. Taken together, these results point to aquatic insects as a possible vector of M. ulcerans.