The Importance of Complementary PCR Analysis in Addition to Serological Testing for the Detection of Transmission Sources of Brucella spp. in Greek Ruminants

Abstract

The early and accurate diagnosis of brucellosis, a ubiquitous zoonotic infection, is significant in preventing disease transmission. This study aimed to assess the infection rate of Brucella spp. in ruminants and to evaluate the agreement between a serological test and a molecular method for the detection of infected cases. Blood and milk samples of 136 ruminants were analyzed using two laboratory methods: the Rose Bengal plate (RBP) test to detect B. abortus and B. melitensis antibodies and the molecular polymerase chain reaction (PCR) method for the presence of bacterial DNA. The agreement between the methods was assessed using the kappa statistic. Based on the RBP test, there were 12 (8.8%) seropositive animals (10 sheep and 2 cows), while 2 (1.4%) samples were positive on PCR analysis. The positive PCR samples were from seronegative cow samples on RBP testing. There was slight agreement (k = −0.02) between the two methods, which was not statistically significant. Our results indicate that complementary molecular methods are useful to detect the bacteria in infected animals that are seronegative due to an early stage of infection. Therefore, a combination of molecular methods and serological tests can be applied to detect brucellosis in ruminants efficiently.

Seroprevalence and molecular detection of brucellosis among Pakistani women with spontaneous abortion

“…The literature presents conflicting findings on the sensitivity and specificity of PCR analysis in detecting infected cases when compared to serological testing. While some research suggests that PCR is more sensitive and specific than serological tests for diagnosing brucellosis, other studies have shown that serological testing has a higher sensitivity ( 39–42 ). In our investigation, the serological testing showed greater sensitivity as indicated by a higher positive rate for the RBPT compared to PCR analysis.…”

Comparison of the Polymerase Chain Reaction Method with Serological Tests in the Diagnosis of Human Brucellosis

“…In line with our study, Rahbarnia et al found that out of 120 patients, 55% had a positive serological test, and 50% had a positive PCR test. Of the 66 patients with positive serological tests for brucellosis, 49 tested positive for PCR (22)(23)(24)(25).…”

An Epidemiological Study of Brucellosis in Different Animal Species from the Al-Qassim Region, Saudi Arabia

“…The direct demonstrations of the causal organism of brucellosis have also been reported using techniques such as animal inoculation, culture, immunofluorescent antibody, polymerase chain reaction (PCR), and staining [ 54 ]. While serological tests are more commonly used to detect brucellosis than other methods, some researchers believe that these tests may not be sensitive enough to detect the disease in its latent or early stages, when animals continue to be asymptomatic in the absence of any visible signs [ 55 ]. A PCR analysis can increase the sensitivity and specificity of detecting the infection and differentiation between Brucella species [ 55 , 56 , 57 , 58 , 59 ].…”

“…While serological tests are more commonly used to detect brucellosis than other methods, some researchers believe that these tests may not be sensitive enough to detect the disease in its latent or early stages, when animals continue to be asymptomatic in the absence of any visible signs [ 55 ]. A PCR analysis can increase the sensitivity and specificity of detecting the infection and differentiation between Brucella species [ 55 , 56 , 57 , 58 , 59 ].…”