NTM Plus Case Studies

Transcription

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2 NTM Plus Case Studies Youngmi Kim, Sr. Microbiologist MS, M(ASCP)

3 Case 1 Referred Culture for ID & appropriate susceptibility

4 Case 1 7/7/15: MGIT broth received DOC: Source: FNA Mesenteric Mass, 44 yo male No previous history of mycobacterial infection MALDI (MGIT): no peaks 7/7/15: TB & MAC PCR Negative 7/15/15: Repeat MALDI(7H10): no peaks

5 Case 1 Kinyoun (MGIT): small/mediumlength acid fast organisms seen Solid media at two weeks: 31 C also showing tiny growth better 37 Next Step: 16s sequencing (7H9)

6 Case 1 7/24/15: 16s sequencing :

7 16s sequencing : M. genavense Repeat MALDI (7H9): M. genavense (1.858, 1.932) Took 3 weeks for ID Isolate sent to National Jewish Health Lab for susceptibility testing (NTM 10 panel) per request

8 M. genavense isolated at WSLH Year Number of Isolates Source Liver tissue, Micronesian Guam Kingfisher (thru June) 0

9 M. genavense continued Relatively new NTM species (1993) Found in tap water, animals, and GI tract of healthy humans/most frequently isolated mycobacterium in parrots & parakeets No human to human transmission Cause disseminated infections in immunocompromised patients, mainly AIDS patients Similar symptoms to MAC infection with more abdominal involvement

10 Comparison: M. genavense to M. avium complex Symptoms Growth on solid media Growth rate Drug resistance to anti TB drugs M. avium complex (MAC) Fever, diarrhea, abd pain, weight loss, lymphadenitis, hepatosplenomegaly Good Fast slow grower More resistant M. genavense Same as MAC but more frequent abdominal pain Poor Better in liquid Very slow grower R to INH

11 M. genavense 4 weeks at 42C Without Mycobactin J in media With Mycobactin J(2ul/ml of media)

12 Case 2 Primary tissue nodule ( right apical ) from 64 yo female Smear: 3+ Positive No previous history TB & MAC PCR: Negative for both Inoculated MGIT(31, 37) & 7H10

13 Case 2 6/19/15 : End of 6 Week Incubation MGIT (31, 37) Final Negative 7H10

14 6/19/15 : End of 6 Week Incubation MGIT (31, 37) Final Negative 7H10 : 4 tiny colonies

15 Kinyoun: Long AFB TB & MAC PCR : negative for both Prelim ID as Mycobacterium sp. not tbc Subcultured on fresh 7H10 MALDI 1 week later :

16 2 week old at 42C

17 Case 2 MALDI 1 week later : M. xenopi (2.246, 2.218) Moved to 42 C incubator

18 Case 2: M. xenopi Slow growing, scotochromogenic First isolated in lesions on a Xenopus laevis (African clawed frog ) in 1959 Low pathogenicity in humans, infections closely associated with immunocompromised individuals Source of human infection: Water Prefer to grow in hot water supplies High incidence in WI

19 Out of 44 M. xenopi isolates recovered by MGIT medium only 13 were detected by the instrument. Round yellow pigmented granules (~0.05 to 0.1 mm) from instrument negative tubes.

20 Lessons Learned 1. Need to check all media before sending out as final negative 2. Need to check instrument negative MGIT tubes for any possible growth

21 Case 3 Tissue(neck) from 46 year-old foreignborn patient Smear 2+ with no previous history TB & MAC PCR

22 TB pcr pos, MAC pcr neg Leftover sediment sent to CDC for MDDR testing Report from CDC: Insufficient DNA for analysis Waited for growth

23 Case 3 After 6 weeks 31 & 37 MGIT Final Negative 7H10 plate Negative Why no growth? Original smear was 2+ Cells all dead?

24 But, 31 MGIT had tiny buff granular growth in liquid media

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26 TB PCR on 31 MGIT : Positive (Ct=19.88) Why No fluorescence? Why growth only in 31 MGIT?

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29 Final Instrument Negative MGIT

30 ~ 1% Instrument negative tubes contained mycobacterial growth. 10% of all positive mycobacterial cultures were instrument negative.

31 Lessons Learned Documented cases where tubes are instrument negative but have viable growth (Pena, et al.) Important to visually check instrumentnegative tubes and solid media for growth before reporting as negative