Efficiency of a Transport Medium for the Recovery of Aerobic and Anaerobic Bacteria from Applicator Swabs

Quantitative cultures were performed on 11 purulent specimens of at least 2 ml from mixed aerobic-anaerobic infections to determine the effect of prolonged exposure to air on the recovery of anaerobes. The specimens were processed immediately and after air exposure for periods of 10 min and 1, 4, and 24 h. There were at total of 37 anaerobic and 36 aerobic strains recovered from these specimens. Of the anaerobes, 26 were isolated with the initial processing and 22 were still present after air exposure for 24 h. The numerical concentrations of anaerobes showed little change with the sequential samplings. Eleven anaerobic strains were not detected in the initial culture but appeared sporadically in subsequent cultures. Using the types of specimens and method of processing employed in this study, most pathogenic anaerobes survived in purulent exudate despite extended periods of air exposure. The major cause of discrepent results with periodic cultures was attributed to vagaries in sampling.

Section: Resultsmentioning

confidence: 99%

Anaerobes survive in clinical specimens despite delayed processing

Bartlett¹,

Sullivan-Sigler²,

Louie³

et al. 1976

“…In our study only 1 (1%) of 75 anaerobic strains was lost over this time period in SGT, and none was lost (0%o) in the FGT and SCB systems. Laboratory evaluations of anaerobic transport systems that used stock cultures generally found heavy die-off of anaerobes in controls exposed to ambient air for 4 to 24 h, and much less in transport systems that were designed to maintain anaerobiosis (1, 3,5,6,15,20,21). And Hallander et al (11), studying specimens from peritonsillar abscesses, encountered marked loss of anaerobic strains in two aerobic transport media, but excellent recovery in evacuated syringes and in gassed-out tubes containing prereduced salt solution.…”

Section: Twentymentioning

confidence: 99%

“…The use of gassed-out tubes (1, 5, 7-9, 11, 12, 17, 18), swabs in Cary and Blair transport medium (8,9,18), and swabs in gassed-out tubes (12) have been recommended and are widely used in many clinical laboratories. Several of these and other transport systems have been studied using stock cultures under conditions simulating clinical use (1, 2, 3,5,6,20,21); however, little information is available regarding their performance with clinical specimens. This study was undertaken to evaluate the ability of three common transport systems to maintain the viability of anaerobic bacteria in specimens from a wide variety of clinical infections, over a 48-h period.…”

mentioning

confidence: 99%

Recovery of anaerobic, facultative, and aerobic bacteria from clinical specimens in three anaerobic transport systems

Helstad¹,

Kimball²,

Maki³

1977

With aspirated specimens from clinical infections, we evaluated the recovery of anaerobic, aerobic, and facultative bacteria in three widely used transport systems: (i) aspirated fluid in a gassed-out tube (FGT), (ii) swab in modified Cary and Blair transport medium (SCB), and (iii) swab in a gassed-out tube (SGT). Transport tubes were held at 25 degrees C and semiquantitatively sampled at 0, 2, 24, and 48 h. Twenty-five clinical specimens yielded 75 anaerobic strains and 43 isolates of facultative and 3 of aerobic bacteria. Only one anaerobic isolate was not recovered in the first 24 h, and then, only in the SGT. At 48 h, 73 anaerobic strains (97%) were recovered in the FGT, 69 (92%) in the SCB, and 64 (85%) in the SGT. Two problems hindered the recovery of anaerobes in the SCB and SGT systems: first die-off of organisms, as evidenced by a decrease in colony-forming units of 20 strains (27%) in the SCB and 25 strains (33%) in the SGT, as compared with 7 strains (9%) in the FGT, over 48 h; and second, overgrowth of facultative bacteria, more frequent with SCB and SGT. The FGT method was clearly superior at 48 h to the SCB and SGT systems in this study and is recommended as the preferred method for transporting specimens for anaerobic culture.

“…Gastrin et al (11) observed growth of C. perfringens suspended in phosphate buffer solution with swabs held in VMG II transport at room temperature. Other workers, however, did not note proliferation in simulated samples held in transport media or in dry gassed-out tubes filled with carbon dioxide (2,25).…”

mentioning

confidence: 96%

“…An identical protocol was followed for the tubes and vials held in the refrigerator. Abbreviations: H, high concentration of bacteria; L, low concentration of bacteria; (2), procedure was run in duplicate; A, PAC used as recommended by the manufacturer; B, vented in an anaerobic glove box; C, vented in air; D, plain vial vented in the glove box; E, plain vial vented in room air. inoculated with 1.0 ml each of high and low concentrations of the bacterial ceil suspensions, as was done with the PAC vials, and vented with 18-gauge cottonplugged hypodermic needles.…”

mentioning

confidence: 99%

Evaluation of Port-A-Cul transport system for protection of anaerobic bacteria

Mena¹,

Thompson²,

Armfield³

et al. 1978

The protection of anaerobes in Port-A-Cul (PAC) transport system (Bioquest, Div. of Becton, Dickinson &Co., Cockeysville, Md.) tubes and vials was studied. Ten species of obligately anaerobic bacteria commonly isolated from clinical specimens were used to prepare simulated swab and fluid specimens in high and low concentrations. Samples in PAC tubes and vials were held for 2, 24, and 48 h at ambient temperature and in a refrigerator. In addition, samples of the simulated specimens were exposed to controlled anaerobic and aerobic conditions in vented tubes and vials, with and without PAC medium, at ambient and refrigerator temperatures. Viable bacterial colony counts from specimens in PAC tubes and vials used as recommended by the manufacturer were consistently greater than those from specimens exposed to the different controlled conditions. The protection in PAC was about equal for specimens with either high or low concentrations of bacteria. Protection of the anaerobes in PAC was more obvious with swab than with fluid specimens. Quantitative recovery of anaerobes from refrigerated PAC samples, with few exceptions, was comparable to that from PAC samples held at ambient temperature.