Prevalência e perfil de suscetibilidade antimicrobiana de bastonetes Gram-positivos isolados de infecções urinárias em um hospital terciário

Abstract

The urinary tract infection (UTI) is a wide incidence disease and can occur at any age, being more frequent in woman. Pregnancy, urinary system malformations, immunossupression, diabetes and invasive procedures on urinary tract are some of risk factors to the development of UTI. Escherichia coli is the most common uropathogen frequently isolated in community and hospitals infections. However, Gram-positive bacilli (GPBs) are also microorganisms commonly isolated from urine culture of elderly, pregnant or individuals who have other risk factors for UTI. Until recently, these microorganisms were misclassified, underreported, and even discarded as likely contaminants. Corynebacterium urealyticum and others Corynebacterium species have been isolated as UTI responsible agents. In addition, there is great concern about strains of antimicrobial resistant GPBs and the emergence of microorganisms resistant to multiple drugs. Therefore, this study aimed to investigate the prevalance and pattern of antimicrobial susceptibilty of GPB isolated from UTI, as well as, evaluate metallo-beta-lactamase-producing and multidrug resistant GPB adhesion pattern to HEp-2 cells. Sixty-five strains of GPBs were isolated from urine samples of patients during the period from September 2015 to August 2016 in a basic unit of private health care in Nova Friburgo / RJ. UTI was more prevalent in women (94.42%), being more often among patients aged 65 to 93 years (37.5%). Mass spectrometry analysis (MALDI-TOF) identified 60 (92.3%) strains of the genus Corynebacterium sp., four (6.1%) Brevibacterium sp., and one (1.54%) Brevibacillus sp. Corynebacterium amycolatum represented 50.8% of all samples isolated in this work, followed by C. aurimucosum (20.83%), C. coyleae (4.17%), C. minutissimum (1.39%), C. propinquum (1.39%), C. striatum (1.39%), B. ravenspurgense (1.53%) and Brevibacillus agri (1.53%). The microrganisms showed more resistance to nitrofurantoin (81.5%), erythromycin (69.2%), penicillin (56.9%), clindamycin (49.2%), trimethoprim/sulfamethoxazole (52.3%), ciprofloxacin (43.1%) and ampicillin (40%). Regarding the production of metallo-beta-lactamase, four strains of C. amycolatum positive were detected through the disk diffusion technique using beta-lactam antibiotics (imipenem and ceftazidime) with metallo-beta-lactamase inhibitors (EDTA and MPA). Twelve bacilli (18.5%) showed multidrug resistance and were submited to the HEp-2 cell adhesion test. Three samples exhibited an aggregative adherence-like pattern to HEp-2 cells (AA) and nine showed localised adherence (LA). This work demonstrates the importance of recognizing Gram-positive bacilli of Corynebacterium genus as uropathogen and demonstrates the need for standardization of identification methods applicable to laboratory routine. Furthermore, reaffirms the concern with emerging antimicrobial resistance and the need for more demanding policies that limit and control the use of antibiotics.