Multiphasic approach reveals genetic diversity of environmental and patient isolates of Mycobacterium mucogenicum and Mycobacterium phocaicum associated with an outbreak of bacteremias at a Texas hospital.
Between March and May 2006, a Texas hospital identified five Mycobacterium mucogenicum bloodstream infections among hospitalized oncology patients using fluorescence high-performance liquid chromatography analysis of mycolic acids. Isolates from blood cultures were compared to 16 isolates from environmental sites or water associated with this ward. These isolates were further characterized by hsp65, 16S rRNA, and rpoB gene sequencing, hsp65 PCR restriction analysis, and molecular typing methods, including repetitive element PCR, random amplified polymorphic DNA PCR, and pulsed-field gel electrophoresis (PFGE) of large restriction fragments. Three of five patient isolates were confirmed as M. mucogenicum and were in a single cluster as determined by all identification and typing methods. The remaining two patient isolates were identified as different strains of Mycobacterium phocaicum by rpoB sequence analysis. One of these matched an environmental isolate from a swab of a hand shower in the patient's room, while none of the clinical isolates of M. mucogenicum matched environmental strains. Among the other 15 environmental isolates, 11 were identified as M. mucogenicum and 4 as M. phocaicum strains, all of which were unrelated by typing methods. Although the 16S rRNA gene sequences matched for all 14 M. mucogenicum isolates, there were two each of the hsp65 and rpoB sequevars, seven PCR typing patterns, and 12 PFGE patterns. Among the seven M. phocaicum isolates were three 16S rRNA sequevars, two hsp65 sequevars, two rpoB sequevars, six PCR typing patterns, and six PFGE patterns. This outbreak represents the first case of catheter-associated bacteremia caused by M. phocaicum and the first report of clinical isolates from a U.S. hospital. The investigation highlights important differences in the available typing methods for mycobacteria and demonstrates the genetic diversity of these organisms even within narrow confines of time and space.
Cooksey
Robert C
RC
Mycobacteriology Laboratory Branch, Centers for Disease Control and Prevention, Mail Stop F08, Atlanta, GA 30333, USA. rcooksey@cdc.gov
Jhung
Michael A
MA
Yakrus
Mitchell A
MA
Butler
W Ray
WR
Adékambi
Toidi
T
Morlock
Glenn P
GP
Williams
Margaret
M
Shams
Alicia M
AM
Jensen
Bette J
BJ
Morey
Roger E
RE
Charles
Nadege
N
Toney
Sean R
SR
Jost
Kenneth C
KC
Dunbar
Denise F
DF
Bennett
Vickie
V
Kuan
Marcella
M
Srinivasan
Arjun
A
D000368:Aged; D016470:Bacteremia / Q000453:epidemiology / Q000382:microbiology*; D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D018834:Chaperonin 60; D018833:Chaperonins / Q000235:genetics; D016000:Cluster Analysis; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology*; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000235:genetics; D004196:Disease Outbreaks; D016521:Electrophoresis, Gel, Pulsed-Field; D004783:Environmental Microbiology; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D006761:Hospitals; D006801:Humans; D008297:Male; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D009161:Mycobacterium / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D009164:Mycobacterium Infections / Q000453:epidemiology / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D019105:Random Amplified Polymorphic DNA Technique; D017422:Sequence Analysis, DNA; D013781:Texas / Q000453:epidemiology
D001426:Bacterial Proteins; D018834:Chaperonin 60; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; C074119:heat-shock protein 65, Mycobacterium; D012321:DNA-Directed RNA Polymerases; C105078:RNA polymerase beta subunit; D018833:Chaperonins