Mycobacterium avium is an environmental organism encountered in natural and urban water sources as well as soil. M. avium biofilm has recently been identified on sauna walls and in city water pipes and might have a role in the survival of virulent strains in the environment and in the host. To characterize the M. avium biofilm, an in vitro model was adapted wherein biofilm develops on a PVC surface. Biofilm was detected by staining with crystal violet and visualization by optical microscopy and quantified by A570. M. avium strains MAC 101, MAC 100, MAC 104, MAC 109, MAC A5 and MAC 5501 (all isolated from the blood of AIDS patients) were used in the assays. Biofilm formation was dependent on the presence of Ca2+, Mg2+ or Zn2+ ions in the water, with the maximal effect seen at a concentration of 1 μM. The presence of 2 % glucose and peptone as sources of carbon increased the formation of biofilm, while this was partially inhibited by humic acid. Since sliding motility has been associated with the amount of glycopeptidolipid (GPL), TLC was used to determine the presence of GPL. The supernatant of a biofilm-forming culture induced formation of a stable biofilm and amikacin blocked the establishment of biofilm by M. avium strains at subinhibitory concentrations. Bacteria in the biofilm were more resistant to chlorine as well as to exposure to potassium monopersulfate and chloroheximide acetate than were planktonic bacteria. Identification of M. avium genes involved in biofilm formation and further studies of the effect of antimicrobials on the establishment of biofilm may identify approaches for inhibiting M. avium biofilm formation and colonization.
BardouniotisE,
HuddlestonW,
CeriH,
OlsonM. E.2001; Characterization of biofilm growth and biocide susceptibility testing of Mycobacterium phlei using the MBEC assay system. FEMS Microbiol Lett 203:263–267
BermudezL. E,
PetrofskyM,
KolonoskiP,
YoungL. S.1992; An animal model of Mycobacterium avium complex disseminated infection after colonization of the intestinal tract. J Infect Dis 165:75–79[CrossRef]
BermudezL. E,
PetrofskyM,
GoodmanJ.1997; Exposure to low oxygen tension and increased osmolarity enhance the ability of Mycobacterium avium to enter intestinal epithelial (HT-29) cells. Infect Immun 65:3768–3773
BodmerT,
MiltnerE,
BermudezL. E.2000; Mycobacterium avium resists exposure to the acidic conditions of the stomach. FEMS Microbiol Lett 182:45–49[CrossRef]
CarsonL. A,
PetersenN. J,
FaveroM. S,
AgueroS. M.1978; Growth characteristics of atypical mycobacteria in water and their comparative resistance to disinfectants. Appl Environ Microbiol 36:839–846
FalkinhamJ. OIII,
NortonC. D,
LeChevallierM. W.2001; Factors influencing numbers of Mycobacterium avium , Mycobacterium intracellulare , and other mycobacteria in drinking water distribution systems. Appl Environ Microbiol 67:1225–1231[CrossRef]
GloverN,
HultzmanA,
AronsonT.8 other authors1994; Isolation and identification of Mycobacterium avium complex recovered from Los Angeles potable water, a possible source of infection in AIDS patients. Int J Environ Health Res 4:63–72[CrossRef]
HaasC. N,
MeyerM. A,
PallerM. S.1983; The ecology of acid-fast organisms in water supply, treatment and distribution system. J Am Water Work Assoc 75:139–144
KirschnerR. AJr,
ParkerB. C,
FalkinhamJ. OIII.
1992; Epidemiology of infection by nontuberculous mycobacteria. Mycobacterium avium , Mycobacterium intracellulare , and Mycobacterium scrofulaceum in acid, brown-water swamps of the southeastern United States and their association with environmental variables. Am Rev Respir Dis 145:271–275[CrossRef]
LimiaA,
SangariF. J,
WagnerD,
BermudezL. E.2001; Characterization and expression of secA in Mycobacterium avium . FEMS Microbiol Lett 197:151–157[CrossRef]
O'TooleG. A,
GibbsK. A,
HagerP. W,
PhibbsP. VJr,
KolterR.2000; The global carbon metabolism regulator Crc is a component of a signal transduction pathway required for biofilm development by Pseudomonas aeruginosa . J Bacteriol 182:425–431[CrossRef]
PrinceD. S,
PetersonD. D,
SteinerR. M,
GottliebJ. E,
ScottR,
IsraelH. L,
FigueroaW. G,
FishJ. E.1989; Infection with Mycobacterium avium complex in patients without predisposing conditions. N Engl J Med 321:863–868[CrossRef]
von ReynC. F,
MaslowJ. N,
BarberT. W,
FalkinhamJ. OIII,
ArbeitR. D.1994; Persistent colonisation of potable water as a source of Mycobacterium avium infection in AIDS. Lancet 343:1137–1141[CrossRef]