How certain is the treatment for pseudomonas?

Question

a)When someone is treated with ciprofloxacin for quite sometime with negative pharyngeal cultures and continues to take the medicine for a little while longer, what are the chances of getting reinfected with pseudomonas during the course of treatment, or immediately after its termination? What are the reasons for the continuation of tandim?
b)After how long can the test trace the pseudomonas (today clean, comes in contact, what does the test show tomorrow?)
c)Is there any chance that the test may be negative, but the patient has pseudomonas? After how many tests with negative results can I be certain that I am clean?

Answer

Dear friend,

a. First of all it is important that we distinguish between 2 stages of Pseudomonas aeruginosa treatment: if P.a. is detected for the first time, a so-called early eradication therapy is initiated; several ways are possible, the one you describe with ciprofloxacin and inhalation of an antibiotic is one of them. This aggressive early therapy has shown to be effective in eradicating P.a. and can delay the onset of a chronic infection with P.a. . So here, we talk about an early therapy of P.a. without a chronic colonization so far. Data from the paper by Döring et al. in 2004 (“Early intervention and prevention of lung disease” in the Journal of cystic Fibrosis) report, that the median time to reinfection after eradication is 8 months (+/- 5.7 months) reported by some investigators, while others (unpublished data from an Italian work group) reported that their patients remained free of P.a. for a mean of 2.4 years after eradication. So many patients have to be treated repeatedly due to recurrent colonization in order to avoid chronic colonization. In Europe ciproxin is used for the treatment of pseudomonas and inhaled antibiotics (tandim). After the termination of the treatment with ciproxin, the administration of inhaled antibiotics is continued for some time as prevention. This usually lasts less than a year.

b. If someone comes in contact with pseudomonas, after some days the changes in the pulmonary epithelial can be detected.

c. Of course, it is always possible, that a test can be falsly negative, would say, P.a. is present but does for example not grow in the bacterial culture for some reason. And as they can persist in low concentrations in some of the airways, it is nearly impossible to prove eradication. Repeated negative respiratory cultures (at least three) within a 6-months period months after cessation of treatment in the presence of negative specific antibodies is practical evidence for eradication.

Dr. Stavros Doudounakis and Dr. Daniela d'Alquen

29.11.2011