Antibiotic resistance may lead to difficulty of treatment of certain livestock diseases. It may cause some losses for its repeated use since bacteria develop resistance to it.

This was according to a research-based investigation that applies recent protocols in the screening and evaluation of antibiotic resistance. The study titled, “Tetracycline and Sulphonamide-Resistance Genes in Respiratory and Gastrointestinal Bacterial Isolates from Cattle (Bos taurus), Goat (Capra hircus), and Sheep (Ovis aries)” provided information about the presence of resistance of certain bacteria to tetracycline and sulphonamide.

In this study, plasmids carrying resistance genes to tetracycline and sulphonamide were detected. It was conducted to ensure systematic disease screening among animals and to maximize production achieved through a systematic animal health program.

“Since the resistance genes are carried by the plasmids, there may be transfer of these genes from one bacterium to other strains and species of bacteria and there is no concrete information on the extent of antibiotic resistance in animal practice in the Philippines,” said Michelle M. Balbin, PCC Science Research Specialist II who conducted the study.

It was funded by the Philippine Carabao Center (PCC) under its Research for Development program.

“We found out through this study that there are genes causing resistance to tetracycline and sulphonamide. These genes are inserting to bacteria, and if the animal got infected with that certain bacteria, and you treat it with tetracycline and sulphonamide, it would be less effective. The bacteria have genes for resistance thus the antibiotics will be less effective, ” Balbin said.

Tetracycline and sulphonide, Balbin stressed, are two popular antibiotics for treating respiratory diseases. But of the two, tetracycline is more utilized since it is a long acting drug and it has various forms like oxytetracycline, doxycycline or minocycline.  It is also  broad spectrum, i.e., that it can cure other diseases like enteritis as long as the causing bacteria are susceptible to these antibiotics.

“These antibiotics are actually effective because they can cure a number of diseases but the problem is that bacteria are already showing resistance so it’s time to limit the use of these antibiotics or other drugs and search for alternatives,” she explained.

According to the study, there are now some procedures and routines undertaken to counter problems in antibiotic resistance such as tracking the resistance frequency, cohorting, and introduction of new therapeutic approaches. But in addition to this, clinically important bacteria are characterized not only by single drug resistance but also by multiple antibiotic resistance, which is the result of the legacy of past decades of antimicrobial use and misuse.

The rate of antibiotic resistance is significant epidemiologically and ecologically. The consequences of resistance must be considered medically and economically in terms of the responses of animals infected with antibiotic-resistant microorganisms, the researcher said.

As indicated in the study, many of the bacterial pathogens associated with epidemics have evolved into multidrug-resistant (MDR) forms prior to antibiotic use. Bacterial pathogens known to have resistance to some antibiotics include Acinetobacter baumannii, Burkholderia cepacia, Campylobacter jejuni, Citrobacter freundii, Clostridium difficile, Enterobacter spp., Enterococcusfaecium, Enterococcus faecalis, Escherichia coli, Haemophilus influenzae, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Salmonella spp., Serratia spp., Staphylococcus aureus, Staphylococcus epidermidis, Stenotrophomonas maltophilia, and Streptococcus pneumonia.

Balbin advised that there should be an establishment of data on the extent of antimicrobial resistance and everyone should be responsible in using these antibiotics. Take note that there already exists Multiple Drug Resistant Bacteria.

Generally, the study was aimed at investigating the tetracycline and sulphonamide-resistance of bacteria related to respiratory and gastrointestinal infections of pigs, small and large ruminants. It specifically sought to evaluate the sensitivity of bacteria and determine the presence of genes that mediate tetracycline and sulphonamide resistance in bacterial isolates of the respiratory and gastrointestinal tract of pigs, small and large ruminants.

Methodologies employed in the study included bacterial strains of six respiratory isolates (Acinetobacter schindleri, Bacillus pumilus, Enterococcus faecalis, Pseudomonas aeruginosa Staphylococcus sciuri and Staphylococcus sporosarcina), in vitro screening for tetracycline and sulphonamide resistance (dilution method), DNA extraction, DNA amplification through Polymerase Chain Reaction, gel electrophoresis of PCR products, and DNA sequencing of tetracycline and sulphonamide resistance genes.

PCR was the technology used to detect plasmid or tetracycline and sulphonamide resistance genes.

Information purposes

“Monitoring of drug resistance is becoming an important component of animal health program. Because of this study, we already have information that certain bacteria have resistance against tetracycline and sulphonamide,” Balbin said.

“So the best thing is either to limit its use because there might come a time that it is no longer effective or look for other alternative methods,” she added. 

She further said that it’s already been suspected that bacteria have high resistance against these antibiotics but there is  limited documentation especially as they relate to Philippine livestock.

“It is a must to examine the bacteria whether it is resistant or susceptible to antibiotics. This kind of practice is usually done in a diagnostic laboratory. Samples are taken and antibiotic sensitivity test is conducted. This examination provides the appropriate antibiotics to be used, but of course in emergency cases we can’t do that. And, that is the importance of establishing data for this matter” she said.

The study recommended further researches that will test the sensitivity of potential pathogens to different kinds of antibiotics as a rational basis for the administration of treatment.

Further works directed toward the molecular detection of antibiotic resistance gene in potential pathogens coming from different body systems are also encouraged in order to come up with complete information on the extent of tetracycline and sulphonamide and other antimicrobial resistance in the veterinary practice or in a particular group of animals.