Molecular Characterization Of Pseudomonas Aeruginosa Clinical Isolates Among Patients Of The Hospital Del Ni?o, Republic Of Panama

摘要

The molecular characterization of 37 clinical isolates of P. aeruginosa obtained during September 2013 and September 2014 was conducted based on the 16S rDNA and oprL genes. The genetic diversity among isolates was determined with ERIC-pcr. The segments of the opr L and 16s rDNA genes were used to detect all P. aeruginosa isolates. The ERIC-PCR bands generated patterns that allowed the separation of isolates into different groups or clades and classify them into different genotypes.The susceptibility pattern of the isolated strains against ceftazidime, imipenem, gentamicin and amikin was assessed by a disk diffusion method. The percentage of isolates resistant to ceftazidime, imipenem, gentamicin and amikin was 14%, 16%, 16% and 24% respectively. In general these percentages are relatively low compared to those reported in other countries and only one of the isolates (64113) showed multidrug resistance. Introduction Pseudomonas aeruginosa is a ubiquitous gram-negative rod shaped bacterium with a polar flagellum. Among fluorescent pseudomonads belonging to the rRNA group I of the gamma subclass of Proteobacteria, it is the only recognized human pathogen (De Vos et al., 2001, Palleroni, 2008).Pseudomonas aeruginosa is a nosocomial human pathogen in immuno-compromised patients, such as those with cystic fibrosis, cancer, burns, and those hospitalized in intensive care units. Infections caused by Pseudomonas species include endocarditis, pneumonia, and infections of the urinary tract, central nervous system, wounds, eyes, ears, skin, and musculoskeletal system. (Pirnay et al., 2000, 2002, Campana et al., 2004). The use of catheters, medical devices, and chemical disinfectants represent an optimal means for acquiring nosocomial infections and therefore efforts to control the spread of the infections are difficult. In addition the emergence of multidrug resistant isolates of P. aeruginosa may lead to severe infections and life-long treatments. These infections are untreatable because of the higher resistance to antimicrobial agents and lack of new drug development (Aendekerk et al., 2005, Stheling et al., 2010, Luna de Araujo, de et al., 2012, Nikbin et al., 2012, Kan et al., 2014).The virulence factors of P. aeruginosa such as exotin A, exoenzyme S, pyoverdine, elastase and sialicidase among others are strongly regulated by cell to cell signaling systems that contribute to its pathogenecity (Cornelis et al., 1989, Van Delden & Iglewski, 1998, Khalifa et al., 2011). The outer membrane proteins of P. aeruginosa play an important role in the bacteria-environment interactions and therefore to the pathogenic infections. The inherent resistance of P. aeruginosa to antibiotics is a consequence of the presence of specific proteins in the outer membrane, efflux pumps that affect cellular permeability. The outer membrane lipoproteins OprL and OprI have been implicated in these efflux transport systems (De Vos et al., 1997, Matthijs, Khattab, et al., 2015).P. aeruginosa identification has been based on phenotypic observations like the growth on selective media such as cetrimide agar, bacto casamino acids, and serotyping and anti-microbial-testing. However other gram-negative bacilli including other Pseudomonas species may interfere with the phenotypic typing of P. aeruginosa and this represents a drawback for the treatment of patients, particularly with regard to antimicrobial therapy and control of infection in hospitals. The genotyping methods solve the variable phenotype problem and are specific for the identification of P. aeruginosa. Since OprL and OprI proteins are found only in this organism they could be a reliable factor for rapid identification of P. aeruginosa in clinical samples. The 16S rDNA gene and the enterobacterial repetitive intergenic consensus sequences (ERIC) have been successfully used in epidemiological studies of several microorganisms, including P. aeruginosa (Stehling et al., 2010).In this study 37 P. aeruginosa cli