Susan E. Sharp

Lactococcus garvieae endocarditis: report of a case and review of the literature

Bacterial endocarditis due to Lactococcus garvieae is extremely unusual, and may actually be underreported due to its morphologic and biochemical similarities with enterococci. Only three cases have been reported in the medical literature, and all involved prosthetic valves. We report a case of native valve bacterial endocarditis caused by L. garvieae.

Clinical assessment of anaerobic isolates from blood cultures

Patients at two tertiary-care medical centers were evaluated to determine the clinical significance of anaerobic isolates from their blood specimens and to identify whether aerobic and/or anaerobic conditions were necessary for the detection of Streptococcus pneumoniae isolates. Significant anaerobes were isolated from only 0.1% and 0.4% of all blood cultures collected. The majority of patients with significant anaerobes had clinical conditions in which anaerobes are known to cause infections. Of the S. pneumoniae organisms, 83% were isolated only from the aerobic bottles of a blood culture set. These data lend support to the recommendations for the selective ordering of anaerobic blood cultures without compromising the isolation of S. pneumoniae.

Löwenstein-Jensen Media

Isolation of mycobacteria on Löwenstein-Jensen media (LJ) and in the BACTEC MB9000 (MB) system was compared. Of 2,271 specimens, 317 were positive for 331 mycobacteria isolated in 1 or both media. The MB was positive in 238 isolates, and LJ was positive for 239 isolates; 92 isolates were detected by MB only and 93 by LJ only. Of the 331 isolates, 146 were recovered by both media. MB recovered 38 of 38 Mycobacterium tuberculosis complex isolates, while LJ recovered 23. MB recovered 94.1% (96/102) of Mycobacterium avium complex isolates and LJ 69.6% (71/102). The MB recovered 81% (65/80) Mycobacterium fortuitum-chelonae isolates and LJ 68% (54/80). Of the remaining species, MB isolated 39, while LJ isolated 91. Only 1 organism that was isolated on LJ alone was medically significant based on medical record review. The addition of LJ media to the MB9000 system is not warranted, as it causes clinically irrelevant workload, increased expenditures for the laboratory, and could cause the inappropriate treatment of patients.

A comparison of the Bactec 9000MB system and the Septi-Chek AFB system for the detection of mycobacteria.

The Bactec MB9000 (MB) continuous monitoring system was compared to the Septic-Chek AFB (SC) for the detection of Mycobacterium species from all patient sources. A total of 1485 specimens were evaluated. Two hundred forty-eight specimens grew mycobacteria in one or both systems. The isolates recovered were 18 Mycobacterium tuberculosis (MTB), 109 M. avium complex (MAC), 59 M. fortuitum-chelonae complex (MFC), 51 pigmented mycobacteria (PGM), and 11 nonpigmented mycobacteria, not MTB/MAC (NP). Of the 248 positive specimens, 157 were positive in both systems; 73 in the SC only; and 18 in the MB only. The mean times to detection for specimens were 11.5 days for MB versus 16.4 days for SC. The false positivity rate in the MB was 5.8%. Contamination rates for the MB and the SC were 12.7% and 19.8%, respectively. These data suggest that the automated MB system has clear advantages over the manual SC system in terms of earlier time to detection of significant mycobacteria, less technical hands-on time, and a lower contamination rate.

Evaluation of the Mycobacteria Growth Indicator Tube compared to Septi-Chek AFB for the detection of Mycobacteria☆☆☆

The Mycobacteria Growth Indicator Tube (MGIT) and the AFB Septi-Check (SC) systems were compared for the ability to detect myobacterial isolates, time to detection, and rate of bacterial contamination. Fifty-eight mycobacterial culture positive specimens were studied. MGIT and SC were both positive in 30 of the 58 specimens (52%); SC alone was positive in 22 (38%), and MGIT alone was positive in 6 (10%) of the 58 specimens. Among the 30 isolates identified in both systems, there were 7 Mycobacterium tuberculosis, 14 M. avium, 6 M. fortuitum-chelonae complex, and 3 other mycobacterial species. MGIT detected Mycobacterium tuberculosis faster; SC detected M. avium complex faster and more often; and M. fortuitum-chelonae isolates were detected at the same rate. MGIT showed more contamination (12.6%) than did the SC (7.8%). MGIT is comparable to SC for the detection of MTB, but MAC isolates were detected more often and faster in the SC system.

Algorithms for wound specimens

Abstract Determining the quality of a wound specimen is the first important step in processing that specimen for bacterial culture. Additionally, the identification and antimicrobial susceptibility testing of isolates from wounds should be directed by the results of the direct Gram-stained smear examination. The Q score can guide the technologist in determining which isolates to identify in these specimens. This scheme can minimize the culturing and/or work up of unacceptable or superficially contaminated specimens, and this, together with decreased expense association with identification to the species level and antimicrobial susceptibility testing, will decrease the cost to the microbiology laboratory. More importantly, use of these guidelines will reduce the reporting of clinically misleading information that might lead to the misdiagnosis of infectious processes and the inappropriate use of antimicrobial agents.

Microbiology director salary survey

How the Survey was Conducted A salary survey of doctorate level microbiologists who direct the activities of clinical or public health microbiology laboratories in the United States and Canada was conducted between July and December of 1998 via an internet users group. Data collected included years of experience, years at current position, type of institution, institution bed size, whether or not an academic appointment was held, and current salary. There were 57 respondents whose responses were tallied as an entire group and in addition were subdivided into seven geographical groups (Northeast, Southeast, North central, South central, Northwest, Southwest, and Canada). Responses were received over the internet, via fax, or by telephone and could be anonymous if the respondent so desired. Statistical analysis was performed in order to answer the following questions: