scholarly journals Sensitivity and Selectivity of Two Commercially Available Media for Legionella spp. Recovery from Environmental Water Samples

Pathogens ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 523
Author(s):  
Savina Ditommaso ◽  
Monica Giacomuzzi ◽  
Gabriele Memoli ◽  
Jacopo Garlasco ◽  
Carla M. Zotti
Keyword(s):  
Quality Control ◽  
Water Samples ◽  
Culture Media ◽  
Environmental Water ◽  
Water Remediation ◽  
Environmental Water Samples ◽  
Sensitivity And Selectivity ◽  
Legionella Species ◽  
Recovery Culture ◽  
Protocol Standardization

The quality control of culture media used for Legionella spp. isolation and enumeration is paramount to achieve a satisfactory degree of comparability among water testing results from different laboratories. Here, we report on a comparative assessment of the sensitivity and selectivity of MWY and BCYEα media supplied by two different manufacturers (i.e., Xebios Diagnostics GmbH and Oxoid Ltd) for the detection of Legionella spp. from environmental water samples. Even though our analysis showed an excellent agreement between the recovery rates of the four media tested (90.5%), the quantitative recovery of Legionella spp. colonies using Xebios media was significantly greater than that achieved by Oxoid media (P = 0.0054). Furthermore, the sensitivity of detection was significantly higher when samples were plated on MWY Xebios agar (P = 0.0442), while the selectivity of MWY appeared to be the same regardless of the manufacturer. Furthermore, MWYXebios agar favored the growth of much larger colonies compared to those observed on MWYOxoid agar. Finally, MWYXebios medium enhanced the recovery of non-pneumophila Legionella species. Collectively, our findings demonstrate that quality control is crucial to ensure high selectivity and sensitivity of the culture media used for the detection and enumeration of Legionella spp. from environmental water resources. As water remediation measures strictly depend on Legionella spp. recovery, culture protocol standardization, as well as quality control of the culture media, is essential to achieve intra- and interlaboratory reproducibility and accuracy.

scholarly journals Effect of the Pretreatment with Organic Acid Buffer Solutions on the Recovery of Legionella Species from Environmental Water Samples

2002 ◽  
Vol 76 (12) ◽  
pp. 1010-1015 ◽  
Author(s):  
Osamu KASUGA ◽  
Kimiko TAKAGI ◽  
Hitoshi MISAWA ◽  
Masato ONOZAWA ◽  
Eiji CHIBA ◽  
...  
Keyword(s):  
Organic Acid ◽  
Water Samples ◽  
Environmental Water ◽  
Environmental Water Samples ◽  
Acid Buffer ◽  
Buffer Solutions ◽  
Legionella Species

scholarly journals Evaluation of a new culture medium for isolation of nontuberculous mycobacteria from environmental water samples

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247166
Author(s):  
Kimberly J. Alexander ◽  
Jennifer L. Furlong ◽  
Julianne L. Baron ◽  
John D. Rihs ◽  
Dominic Stephenson ◽  
...  
Keyword(s):  
Water Samples ◽  
Nontuberculous Mycobacteria ◽  
Culture Media ◽  
Severe Disease ◽  
Environmental Water ◽  
Water Systems ◽  
Environmental Water Samples ◽  
Primary Concern ◽  
Species List ◽  
Pre Treatment

Nontuberculous mycobacteria (NTM) are waterborne pathogens commonly found in building water systems where they are a primary concern to vulnerable patient populations and can cause severe disease. The recovery of NTM from environmental samples can be a laborious undertaking and current pre-treatment methods and selective media lack sensitivity. We explored the use of the highly selective Rapidly Growing Mycobacteria (RGM) medium for culturing NTM from environmental water samples compared to existing methods. In total, 223 environmental water samples, including potable and non-potable water, were cultured for NTM using three culture media. In addition to direct culture on RGM medium, each sample was cultured on Middlebrook 7H10 medium and Mitchison 7H11 medium after pre-treatment with 0.2M KCl-HCl. Additionally, 33 distinct species of NTM were inoculated onto RGM medium and 7H10 medium in parallel to directly compare their growth. The use of RGM medium alone without pre-treatment provided a sensitivity (91%) comparable to that offered by culture on both 7H10 and 7H11 with acid pretreatment (combined sensitivity; 86%) with significantly less overgrowth and interference from other organisms on RGM medium. The average concentration of NTM observed on RGM medium alone was comparable to or greater than the NTM concentration on either medium alone or combined. Thirty-three species were examined in parallel and all tested strains of 27 of these species successfully grew on RGM medium, including 19 of 21 from the CDC’s healthcare-associated infections species list. RGM medium was successful at recovering environmental NTM without a pre-treatment, greatly reducing labor and materials required to process samples. Simplification of culture processing for environmental NTM will allow for a better assessment of their presence in building water systems and the potential for reduced exposure of susceptible populations.

Improving Mycobacterium spp. detection in water: a new methodological proposal

2004 ◽  
Vol 4 (2) ◽  
pp. 103-106
Author(s):  
R. Santos ◽  
S. Gonçalves ◽  
F. Macieira ◽  
F. Oliveira ◽  
R. Rodrigues ◽  
...  
Keyword(s):  
Water Samples ◽  
Recovery Rate ◽  
Opportunistic Infections ◽  
Environmental Water ◽  
Environmental Water Samples ◽  
Sample Treatment ◽  
Detection Time ◽  
Fast Detection ◽  
Enrichment Step ◽  
Mycobacterium Spp

In recent years, non-tuberculous mycobacteria (NTM), once considered merely environmental saprophytes, have emerged as a major cause of opportunistic infections. There is no evidence of human-to-human transmission but they have been found in several environmental water samples. It is, therefore, of the utmost importance to develop methods of rapidly and accurately detecting non-tuberculous mycobacteria in water samples. To obtain a maximum recovery rate and a reduction of Mycobacterium spp. detection time in water samples, different decontamination, enrichment procedures and antibiotics supplements were tested before the inoculation into the Bactec® system. The proposed method of sample treatment (decrease in the decontamination time, followed for a peptone pre-enrichment step and an aztreonam and cefepime supplement) before the inoculation into the Bactec® system proved to be a good option for reliable and fast detection of Mycobacterium spp. in water samples.

The Occurrence of Male-Specific and Somatic Bacteriophages in Polluted South African Waters

1991 ◽  
Vol 24 (2) ◽  
pp. 251-254 ◽  
Author(s):  
R. Kfir ◽  
P. Coubrough ◽  
W. O. K. Grabow
Keyword(s):  
South African ◽  
Water Samples ◽  
Biological Treatment ◽  
Environmental Water ◽  
Environmental Water Samples ◽  
Resistance Pattern ◽  
Male Specific

The occurrence of somatic (F') and male-specific (F') coliphages and Salmonella phages in a variety of environmental water samples was studied using different bacterial hosts. The number of plaque-forming units (pfu) of the different bacteriophages were compared and their resistance pattern to a biological treatment (humus tank) and chlorination was evaluated. The presence of the bacteriophages in shellfish was also studied. The morphology of isolate bacteriophages was examined as well as the visibility of the different plaques formed. Coliphages were found to produce larger and clearer plaques than all other bacteriophages studied. In most of the environmental water samples coliphages outnumbered all other bacteriophages, with the exception of dam water in which higher levels of F' Salmonella phages were detected. The majority of the F' Salmonella phages were shown to be RNA bacteriophages.

Sign in / Sign up

Export Citation Format

Share Document