Evaluation of clinical application of different microbial automated inoculation systems / 中华检验医学杂志

ABSTRACT

Objectives To study the performance of different microbial automated inoculation systems and to evaluate the performance of the Probact microbial automated inoculation and incubation system ( Probact system) and its applications in clinical microbiology laboratory.Methods A total of 160 clinical specimens, including respiratory secretions ( n=61 ) , urine ( n=49 ) , and feces ( n=50 ) , that were submitted to the Clinical Microbiology Laboratory in Peking Union Medical College Hospital of Chinese Academy of Medical Sciences from February 2015 to April 2015 were evaluated.These specimens were processed with conventional manual method, the Probact automated inoculation system, and PREVI Isola Inoculator.The quantity of bacterial species recovery, number of effectively isolated colonies, total number of colonies recovery per plate, and time of processing the 160 specimens by the three methods were evaluated. Wilcoxon signed-rank test and Kruskal-Wallis rank sum test were used for statistical analysis.Results The Probact system had significantly higher quantity of bacterial species recovery (respiratory specimens 3.41 ±1.40, urine 1.92 ±0.86, and feces 1.16 ±0.79) than those by the Isola Inoculator (respiratory specimens 3.75 ±1.29, urine 2.24 ±0.97, and feces 1.92 ±0.72), (P=0.006, 0.011, <0.001).Compared to the manual method, Probact performed less quantity of bacterial species recovery for respiratory specimens(3.85 ±1.38), but higher in feces(0.80 ±0.81)( P<0.001).There is no significant differences for urine ( 1.84 ±1.23 ) ( P=0.266 ) .As for number of isolated colony, the Probact system ( respiratory specimens 12.16 ±7.72, urine 2.71 ±4.24, and feces 5.40 ±5.04 ) had significant smaller numbers than that of Isola Inoculator (respiratory specimens 16.56 ±5.76, urine 4.35 ± 4.89, and feces 8.40 ±3.70) (P<0.001,0.007,0.003).However, both system had larger numbers of isolated colonies than those by the manual method (respiratory specimens 11.30 ±8.42, urine 2.67 ±4.34, and feces 1.90 ±3.90) and the difference was significant for fecal specimens(P<0.001).Regarding the total number of colonies recovery, larger number was found by Isola Inoculator than that by the Probact system for fecal specimens, however, there were no significant differences for respiratory or urine specimens (P=0.524,0.738).Compared with manual method, the Probact system had significantly more numbers of colonies recovery for respiratory and fecal specimens ( P<0.001 ) . The total time for processing 160 specimens was shortest for manual method (281 min), followed by Probact system (419 min) and Isola Inoculator (495 min) .Conclusions The performance of the Probact system is better than the manual method but no superior to the Isola Inoculator.The Probact system can meet the clinical need in terms of full automation and standardization of specimen inoculation and prevention of bias of processing by laboratory staffs using manual method.