Why do antibiotics not work well against pseudomonas aeruginosa?

Various reasons. Pseudomonas is a very common bacteria which has developed many clever ways of resisting different antibiotics. It can destroy the antibiotics with chemicals, pump the antibiotics out of its cell or become 'invisible' to antibiotics by changing the appearance of the bacteria. Pseudomonas can adapt to antibiotics & change during the course of treatment. Serious infections often require an expert.
Antibiotics. Pseudomonas is a gram negative rod bacteria that lives in soil and water. Although it is true that pseudomonas is resistant to many antibiotics, there are quite a few that, when given iv, are effective against this bacteria. The resistance is due to the mechanism of metabolism that has evolved to "inactivate" less powerful antibiotics and oral antibiotics.

Related Questions

Can monobactams work to treat pseudomonas aeruginosa?

Maybe. Monobactams are drugs chemically similar to the penicillins. The only commercially available monobactam in the United States is a drug called aztreonam, it is effective against some strains of pseudomonas but not all. Because of this it is more of a second choice agent in those who can not take drugs that have greater efficacy because of allergies etc.
Yes. But this depends upon what infection and the sensitivities of the strain of pseudomonas with which the patient is infected.
Aztreonam. Is the only monobactam available in the usa. It does have activity against pseudomonas but hospital strains may be resistant.

Can cephalosporins work to treat pseudomonas aeruginosa?

Sometimes. There are several kinds or "generations" of cephalosporins antibiotics, which are antibiotics that are chemically related to penicillin. Some of the drugs in this class are highly effective against pseudomonas and some are not. In fact this can vary to some degree depending on the antibiotic sensitivities specific to the pseudomonas strains prevalent in a particular hospital or community.
Yes some. There are many different cephalosporin antibiotics. Many are not effective against ps. Aer. Those that are active against this organism are Fortaz (ceftazidime) and maxipime (cefepime).

My coworker has pseudomonas aeruginosa that has caused a corneal ulcer. Should I be worried of contracting it as well?

Probably not. Corneal ulcers are generally not contagious, unless you are directly handling and administering eye drops to someone who is infected. Hand washing and using the alcohol based disinfectants should reduce all risk. Or, don't touch your own eyes - then you should have no risk. (note: viral eye infections like common "pink eye" are much more contagious, and can be picked up off of inanimate objects.).
No. Assuming your coworker is not rubbing her infected eye and then touching surfaces that you touch prior to touching your eyes, the risk is negligable. The bacteria does not have an airborne transmission mode of spread.

Can good hygiene prevent pseudomonas aeruginosa infection?

Yes and no. Pseudomonas can be transmitted differently - contact exposure, airborne. Also, it may live on some of us without causing any disease, but when local immunity diminishes, it may start causing a problem. Skin infections caused by pseudomonas mandate usual hygiene measures such as hand washing, using protective wear, disposal of infected materials etc. But not 100% guarantee of protection.
Yes and No. Depends where. If you step on a nail and it goes through your shoe the wound is prone to psuedomonas aeruginosa because it is in the glue of your shoe. You can't help that. If you are a girl, wiping from from to back can prevent the bacteria in a uti.

I am immuno-compromised, am I more likely to get pseudomonas aeruginosa?

Yes. Yes you are. It is an opportunistic infection that is more prevalent in people with immunodeficiencies/suppression.
Possibly. Ps. Aeruginosa infections are most commonly acquired in the hospital setting. They are very common in cystic fibrosis patients. Some compromise in the host health status underlies most of the serious problems with ps. Aer. Infections. Main host factors that affect risk are low white blood cell count, burn wounds or other disruption of skin or mucosal surfaces.