Posted by: antibioticresidues | November 2, 2009

First newsletter on antibiotic residues

The topics I’ll be sharing with you won’t be some hard core technical mumble jumbo materials you get from a PhD thesis, but materials full of interesting facts and ideas.

I’ll also be addressing some of the pressing issues facing the dairy industry, but more importantly getting you aware of fundamentals surrounding basic antibiotic testing and helping improve everyone’s awareness on a simple, yet complex topic.

You’ll learn how certain antibiotic concoctions can pass through a microbial inhibition test, why some cleaning agents can give you a false positive result, why high colostrum can also affect the readings and so much more.

On the other side, you’ll also see how certain farmers are becoming more proactive in their approach to on-farm antibiotic testing. 

Just imagine finally having a newsletter, written by someone from the dairy industry that knows the topic, but can explain it to you in a simple, easy to read format.

Understanding Beta Lactam and Cephalosporins 

Now a newsletter on antibiotic wouldn’t be interesting if it didn’t include something about the different types of antibiotics available. But rather than give you a long list of every single antibiotics available, which will add to the confusion and complexity. I’ll start by introducing to you the common families of drugs. They include the Beta-Lactam, Cephalosporins (Beta-lactam), Tetracyclines, Macroglides, Sulfonamides, Aminoglycosides and others which I’ll elaborate on in the future.


But first, let’s talk about the Beta-lactam antibiotics. It’s the most common family of antibiotics available for use around the world because of its low toxicity. Its chemical structure has a distinct ring called the “Beta-lactam ring” as shown by the square ring within each of the chemical structure shown in the picture below.

family tree of antibiotics

Family tree of beta-lactam antibiotics

This ring and its derivatives are agents that are active against many micro-organisms such as those causing mastitis.


Structurally, cephalosporins are part of the bata-lactam group as they have a beta-lactam ring (which they share with all penicillins), but what sets them apart is the addition of a thiazolidine ring.

Did you know that cephalosporins are often thought of as new and improved derivatives of the penicillins and was actually discovered as naturally occurring substances by the fungi (Cephalosporium acremonium). Incidentally, this mould was first isolated from sewage!

I hope that wasn’t too technical, but since beta-lactam and cephalosporins accounts for the majority of antibiotics used. I had to go a bit technical. Stay tuned for my next issue on the microbial inhibition test.  

David Wong

This newsletter is a service of Arrow Scientific

Posted by: antibioticresidues | October 30, 2009


Welcome to the world of Antibiotic residues!