Technonews: Research on the sensitivity of bacteria and mycoplasmas from animal origin to doxycycline (Part 2)



The sensitivity of different animal-based microbes to doxycycline has been evaluated in multiple studies, some of which are cited below.

III.1. Sensitive Microorganisms

a) Mycoplasma spp.

M. synoviae is responsible for infectious synovitis in chickens and turkeys and causes considerable economic losses to the poultry industry. It is also associated with respiratory tract infections and seizures by aerosaculitis, in addition to causing subclinical infections.

Doxycycline is effective in killing Mycoplasma spp. thanks to its high penetration capacity (liposolubility). This is corroborated by a study carried out in the Netherlands, where doxycycline was effective in eradicating M. synoviae in a broiler farm [1].

b) Brucella

Brucellosis is a contagious disease of livestock that has significant economic consequences. It is characterized by the existence of abortions or lack of reproduction.

In a study carried out in Iran with different species of the genus Brucella, it was observed that all the microbial samples collected from ruminants were sensitive to doxycycline. These results indicate that doxycycline was the most effective antibiotic against Brucella [2].

Despite the demonstrated efficacy of the antibiotic, treatment of brucellosis in animals is not recommended due to the need to eradicate the disease [3].

c) Pasteurella multocida

It is the bacterium responsible for avian cholera, atrophic rhinitis in pigs and hemorrhagic septicemia in cattle.

In a study carried out in Hungary with isolates of P. multocida obtained from birds (20) and pigs (36) it was observed that P. multocida is susceptible to doxycycline, since only 3% of the strains obtained from pigs showed resistance (See Table 1) [4].

Antimicrobial agent

% of strains of birds

% of strains of pigs












TABLE 1. S = sensitive; I = Intermediate sensitivity; R = Resistant. (Sellyei et al. 2009)

The results differ from those obtained in a trial conducted in India with P. multocida of birds with avian cholera, as 56.91% of the strains proved to be susceptible to the antibiotic (see Table 2) [5].

Antimicrobial agent

Concentration (mcg/disco)

Nº of resistant (%)

Nº of Intermediates (%)

Nº of sensitive (%)



21 (25.20)

22 (17.89)

70 (56.91)

TABLE 2. (Shivachandra et al. 2004)

Doxycycline can be combined with tiamulin to obtain a synergistic effect against P. multocida and Mycoplasma [6].

Abstract: Sensitive microorganisms

  • Doxycycline has proved to be effective against Mycoplasma spp. of avian origin.

  • Doxycycline has proved to be effective against Brucella isolated in ruminants.

  • There are variations in the prevalence of doxycycline resistance in P. multocida of avian origin.


[1] W. J. Landman, D. J. Mevius, K. T. Veldman, and a Feberwee, “In vitro antibiotic susceptibility of Dutch Mycoplasma synoviae field isolates originating from joint lesions and the respiratory tract of commercial poultry.,” Avian Pathol., vol. 37, no. 4, pp. 415–20, 2008.

[2] G. R. Irajian, F. M. Jazi, R. Mirnejad, and V. Piranfar, “species-specific PCR for the Diagnosis,” vol. 11, no. 3, pp. 238–247, 2016.

[3] M. K. Glynn and T. V Lynn, “Zoonosis Update – Brucellosis,” J. Am. Vet. Med. Assoc., vol. 233, no. 6, pp. 900–908, 2008.

[4] B. Sellyei, Z. Varga, K. Szentesi-Samu, E. Kaszanyitzky, and T. Magyar, “Antimicrobial susceptibility of Pasteurella multocida isolated from swine and poultry.,” Acta Vet. Hung., vol. 57, no. 3, pp. 357–67, 2009.

[5] S. B. Shivachandra, A. A. Kumar, A. Biswas, M. A. Ramakrishnan, V. P. Singh, and S. K. Srivastava, “Antibiotic Sensitivity Patterns among Indian Strains of Avian Pasteurella multocida,” Trop. Anim. Health Prod., vol. 36, no. 8, pp. 743–750, 2004.

[6] K. M. S. Islam, U. Klein, and D. G. S. Burch, “The activity and compatibility of the antibiotic tiamulin with other drugs in poultry medicine–A review.,” Poult. Sci., vol. 88, no. 11, pp. 2353–2359, 2009.

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