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NAME: Lactobacillus spp.

SYNONYM OR CROSS REFERENCE: Lactobacillus, lactobacillemia Footnote 1, Footnote 2.

CHARACTERISTICS: Lactobacillus species are members of the Lactobacillaceae family Footnote 1. They are gram positive rods or coccobacilli and occasionally form short chains Footnote 1, Footnote 3. These fermentive bacteria are chemo-organotrophic and microaerophilic. Although they require rich media to grow, they are ubiquitous and may survive anywhere there are carbohydrates (e.g. food; respiratory, gastrointestinal, and urogenital tract of human and animals; sewage; and plant material). They are non spore-forming and lack motility. They are commonly used to ferment food and as probiotics Footnote 3. They may be also used as a treatment for infantile and adult diarrhoea, candidal vaginitis, and antibiotic-associated diarrhoea Footnote 3.


PATHOGENICITY/TOXICITY: Lactobacilli are part of the normal flora of the human mouth, gastrointestinal tract and female genital tract Footnote 2, Footnote 3, and are generally regarded as safe for use in food (probiotics and to ferment food) Footnote 3. Lactobacillus infections are rare; but can occur opportunistically, especially in immunocompromised individuals Footnote 2. Most deaths associated with Lactobacillus infections are in individuals with underlying immunosuppressive conditions. L. acidophilus is implicated in dental caries (tooth decay) Footnote 4.

Some probiotics and indigenous flora have been reported to be able to translocate from the gastro-intestinal tract to other organs Footnote 5. In immunocompromised individuals, this translocation may be responsible for bacteremia, septicaemia, and multiple organ failure. No cases of sickness from ingesting probiotics have been reported to date in healthy subjects, even if translocation was observed. For patients with cancer, diabetes, AIDS, valvulopathy, or who have had broad spectrum antibiotic treatment, organ transplantation, or abscess, the risk of infection with probiotics is higher, but still very low. L. rhamnosus has a greater potential to translocate than other lactobacilli.

EPIDEMIOLOGY: Infections occur worldwide. Immunocompromised patients are at greatest risk of infection and adverse outcomes Footnote 3.

HOST RANGE: Humans and animals. Lactobacilli are part of the normal flora of humans and animals Footnote 1.


MODE OF TRANSMISSION: The primary mode of transmission is ingestion. Vertical transmission can occur during delivery Footnote 3, Footnote 6.

INCUBATION PERIOD: Unknown. Part of the normal human mouth, gut, and vaginal flora.

COMMUNICABILITY: Transmission within families has been documented Footnote 7.


RESERVOIR: They are part of the normal flora of humans and animal Footnote 1.

ZOONOSIS: Unknown.



DRUG SUSCEPTIBILITY: Lactobacillus spp. are susceptible to intravenous penicillin, ampicillin, and aminoglycosides (typically gentamicin) Footnote 3.

SUSCEPTIBILITY TO DISINFECTANTS: Quaternary ammonium compounds, phenolic disinfectants, 1% sodium hypochlorite, 70% ethanol, formaldehyde, glutaraldehyde, iodophore, and peracetic acid are effective against Lactobacilli. Footnote 8.

PHYSICAL INACTIVATION: Lactobacilli are inactivated by UV, microwave, gamma radiation, moist heat (121°C for at least 20 min) and dry heat (165-170°C for 2 h) Footnote 9-Footnote 12.

SURVIVAL OUTSIDE HOST: Lactobacilli were found in 105 years old cheese.

L. acidophilus may survive more than 20 days in soy-based cream cheese, and L. casei may survive 2 days in feces, Lactobacillus may survive at least 7 weeks in yoghurt with a 3 log cycle loss, and survival is improved with microencapsulation (only 2 log loss) Footnote 13-Footnote 15.


SURVEILLANCE: Monitor for symptoms Footnote 3 Lactobacilli may be difficult to identify, because medical laboratory commercial tests are not sufficient for a correct identification. Species-specific PCR, Random Amplification of Polymorphic DNA (RAPD)-based PCR, and 16S-23S amplified rDNA restriction analysis can be used with varying ability to discriminate between strains Footnote 16, as well as sequencing of the 16S rRNA gene.

Note: All diagnostic methods are not necessarily available in all countries.

FIRST AID/TREATMENT: Give appropriate antibiotic therapy Footnote 3.

IMMUNIZATION: None available.

PROPHYLAXIS: None available.


LABORATORY-ACQUIRED INFECTIONS: No laboratory-acquired infections have been reported to date Footnote 3.

SOURCES/SPECIMENS: Lactobacilli may be found in feces, blood, vaginal swab, specimen from mouth, and various body tissues Footnote 1, Footnote 3.

PRIMARY HAZARDS: Accidental parenteral inoculation and ingestion.




CONTAINMENT REQUIREMENTS: Containment Level 1 facilities, equipment, and operational practices for work involving infected or potentially infected material.

PROTECTIVE CLOTHING: Properly fastened protective laboratory clothing. Gloves when direct skin contact with infected materials or animals is unavoidable Footnote 17.



SPILLS: Allow aerosols to settle and, wearing protective clothing, gently cover spill with paper towels and apply an appropriate disinfectant, starting at the perimeter and working towards the centre. Allow sufficient contact time before clean up.

DISPOSAL: Decontaminate all wastes that contain or have come in contact with the infectious organism by autoclave, chemical disinfection, gamma irradiation, or incineration before disposing

STORAGE: The infectious agent should be stored in leak-proof containers that are appropriately labeled.


REGULATORY INFORMATION: The import, transport, and use of pathogens in Canada is regulated under many regulatory bodies, including the Public Health Agency of Canada, Health Canada, Canadian Food Inspection Agency, Environment Canada, and Transport Canada. Users are responsible for ensuring they are compliant with all relevant acts, regulations, guidelines, and standards.

UPDATED: December 2011

PREPARED BY: Pathogen Regulation Directorate, Public Health Agency of Canada.

Although the information, opinions and recommendations contained in this Pathogen Safety Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.

Copyright ©
Public Health Agency of Canada, 2011


Footnote 1
Felis, G. E., & Dellaglio, F. (2007). Taxonomy of Lactobacilli and Bifidobacteria. Current Issues in Intestinal Microbiology, 8(2), 44-61.

Footnote 2
Schlegel, L., Lemerle, S., & Geslin, P. (1998). Lactobacillus species as opportunistic pathogens in immunocompromised patients. European Journal of Clinical Microbiology & Infectious Diseases : Official Publication of the European Society of Clinical Microbiology, 17(12), 887-888.

Footnote 3
Cannon, J. P., Lee, T. A., Bolanos, J. T., & Danziger, L. H. (2005). Pathogenic relevance of Lactobacillus: a retrospective review of over 200 cases. European Journal of Clinical Microbiology & Infectious Diseases : Official Publication of the European Society of Clinical Microbiology, 24(1), 31-40. doi:10.1007/s10096-004-1253-y

Footnote 4
Shivakumar, K. M., Vidya, S. K., & Chandu, G. N. (2009). Dental caries vaccine. Indian Journal of Dental Research : Official Publication of Indian Society for Dental Research, 20(1), 99-106.

Footnote 5
Liong, M. T. (2008). Safety of probiotics: translocation and infection. Nutrition Reviews, 66(4), 192-202. doi:10.1111/j.1753-4887.2008.00024.x

Footnote 6
Hammes, W. P., Weiss, N., & Holzapfel, W. (1992). The genera Lactobacillus and Carnobacterium. The Prokaryotes, 2, 1535-1573.

Footnote 7
Oberhelman, R. A., Gilman, R. H., Sheen, P., Taylor, D. N., Black, R. E., Cabrera, L., Lescano, A. G., Meza, R., & Madico, G. (1999). A placebo-controlled trial of Lactobacillus GG to prevent diarrhea in undernourished Peruvian children. The Journal of Pediatrics, 134(1), 15-20.

Footnote 8
Collins, C. H., & Kennedy, D. A. (1999). Decontamination. Laboratory-Acquired Infections: History, Incidence, Causes and Prevention. (4th ed., pp. 160-186). London, UK: Buttersworth.

Footnote 9
Katara, G., Hemvani, N., Chitnis, S., Chitnis, V., & Chitnis, D. S. (2008). Surface disinfection by exposure to germicidal UV light. Indian Journal of Medical Microbiology, 26(3), 241-242.

Footnote 10
Wu, Y., & Yao, M.Inactivation of bacteria and fungus aerosols using microwave irradiation. Journal of Aerosol Science, In Press, Corrected Proof doi:DOI: 10.1016/j.jaerosci.2010.04.004

Footnote 11
Farkas, J. (1998). Irradiation as a method for decontaminating food. A review. International Journal of Food Microbiology, 44(3), 189-204.

Footnote 12
Csucos, M., & Csucos, C. (1999). Microbiological obseration of water and wastewater. United States: CRC Press.

Footnote 13
Liong, M. T., Easa, A. M., Lim, P. T., & Kang, J. Y. (2009). Survival, growth characteristics and bioactive potential of Lactobacillus acidophilus in a soy-based cream cheese. Journal of the Science of Food and Agriculture, 89(8), 1382-1391.

Footnote 14
Oozeer, R., Leplingard, A., Mater, D. D., Mogenet, A., Michelin, R., Seksek, I., Marteau, P., Dore, J., Bresson, J. L., & Corthier, G. (2006). Survival of Lactobacillus casei in the human digestive tract after consumption of fermented milk. Applied and Environmental Microbiology, 72(8), 5615-5617. doi:10.1128/AEM.00722-06

Footnote 15
Kailasapathy, K. (2006). Survival of free and encapsulated probiotic bacteria and their effect on the sensory properties of yoghurt. LWT-Food Science and Technology, 39(10), 1221-1227.

Footnote 16
Markiewicz, L. H., Biedrzycka, E., Wasilewska, E., & Bielecka, M. (2010). Rapid molecular identification and characteristics of Lactobacillus strains. Folia Microbiologica, 55(5), 481-488. doi:10.1007/s12223-010-0080-z

Footnote 17
Public Health Agency of Canada. (2004). In Best M., Graham M. L., Leitner R., Ouellette M. and Ugwu K. (Eds.), Laboratory Biosafety Guidelines (3rd ed.). Canada: Public Health Agency of Canada.