Prevalence ofPseudomonas aeruginosapyocin and antibiotic biotypes in four Tehran hospitals

Abstract

Over a 15-month period, 340 strains of Pseudomonas aeruginosa were isolated from clinical specimens, i.e. sputum, wound swabs, pus, burns, urine, stool, etc., and the environment, i.e. sink, floor, bed sheets, etc., in four Tehran hospitals. Identification of Pseudomonas aeruginosa was carried out by standard methods. Pyocin typing and subtyping were done using the spotting method of Govan, and using a set of 13 indicator strains. Results of the study showed that the dominant pyocin types were PT10, PT4 and PT3, with frequencies of 30.6%, 21.7% and 8.8%, respectively. The pyocins had a wide spectrum of activity, in contrast to most other bacteriocins known. The dominant pyocin subtypes observed in this study were b, d, a, and c, with frequencies of 18.4%, 14.9%, 12.7%, 9.2%, respectively. Approximately 95.9% of the isolates were typable. 98.8% of the Pseudomonas aeruginosa isolates were resistant to 1 or more antibiotics tested. Antibiotic sensitivity tests were performed using the disc diffusion method, employing Mueller-Hinton Agar. The following antibiotics were tested: Aztreonam (ATM), Ceftazidime (CAZ), Ceftriaxone (CRO), Imipenem (IMP), Cefoperazone (CFP), Amikacin (AN), Sisomicin (SIS), Polymyxin B (PB), Gentamicin (GM), Tobramycin (NN), Netilmicin (NET), Tetracycline (TE) and Carbenicillin (CB). The highest resistance was observed against tetracycline (98.2%), while no resistance was detected against polymyxin B. Among betalactams, ceftazidime and among aminoglycosides, amikacin showed the greatest activities. Distribution of these isolates from the hospital environments was alarming. The results of these findings were reported to the hospital authorities and a number of preventive and control measurements, including more effective methods of disinfection for all instruments that come into contact with patients, were suggested to reduce the spread of the bacterium.

Prevalence of Multiple Antibiotics Resistant (MAR) Pseudomonas Species in the Final Effluents of Three Municipal Wastewater Treatment Facilities in South Africa

“…[67] reported Pseudomonas isolates that were resistant to only single antibiotics, all the tested isolates in this study showed multiple antibiotic resistances (MARs) ranging from five to 11 antibiotics distributed among three to seven classes. Consistent with the observation of this study, Paul et al .…”