Prevalence and evaluation of resistance to antibiotics of genera Proteus, Morganella and Providencia isolates in University Hospital of Constantine, Algeria

The three genera Proteus, Morganella and Providencia (PMP) are opportunistic microorganisms which cause serious hospital and community infections. However, in many laboratories in developing countries, differentiation of these genera into species is not generally done during bacteriological diagnosis due to high cost and special skills involved. This study aimed at determining the occurrence and antimicrobial susceptibility of genera PMP isolated from different clinical samples in Constantine, Algeria. 17 834 clinical samples were collected in the Clinical Microbiology Laboratory of Benbadis University Hospital in Constantine, during the year 2011. The isolates were identified to the species level using conventional biochemical tests and the identification was confirmed on the basis of the results of Analytical Profile Index API20E tests. Antimicrobial susceptibility of isolates was determined by the disk-diffusion method on Mueller-Hinton Agar. 4173 were positive (23.40% of total samples). Four PMP species were recovered from 304 of 4173 positive result giving 7.28 % prevalence of PMP infections mainly isolates from in-patients (78.95%); Proteus mirabilis was the commonest (70.06 %), followed by Proteus vulgaris (15.13 %). Morganella morganii accounted for (10.19 %) and Providencia stuartii (4.60 %). Strains of PMP most commonly isolated from pus (47.04 %) followed by urine samples. All of PMP strains isolated were susceptible to carbapenems. We reported that strains were generally susceptible to Cefoxitin, Cefotaxime, Imipenem, Amikacin, Ciprofloxacin. We observed a high percentage of PMP strains resistant to Amoxicillin, Nalidixic acid, Triméthoprim/ sulfamethoxazol. However, M. morganii and P. stuartii isolates exhibited a high resistance to Ticarcillin, Gentamicin, Chloramphénicol. More than 61% of all strains were found to be multiple drugs resistant. Extended Spectrum ?-Lactamases (ESBL) were produced by 10.33 - 16.13 % of PMP strains.