Analysis of multidrug-resistant bacteria in 3223 patients with hospital-acquired infections (HAI) from a tertiary general hospital in China

Abstract

The frequency of antimicrobial resistance has increased globally due to misuse and overuse of antibiotics, and multi-drug resistant (MDR) bacteria are now recognized as a major cause of hospital-acquired infections (HAI). Our aim was to investigate the prevalence, distribution, and antimicrobial susceptibility rates of MDR bacteria in patients with HAI from a tertiary hospital in China. We retrospectively evaluated all patients with a confirmed diagnosis of bacterial infection at a tertiary general hospital in Jining, for the period between January 2012 and December 2014. The following clinical and demographic data were collected: age, sex, specimens, treatment, microbiology results, and antibiotic resistance patterns of isolates. Bacterial identification and susceptibility testing were performed using VITEK 2 COMPACT system. We screened a total of 15,588 patients, out of which 7579 (48.6%) had an HAI. MDR showed 3223 out of 7579 isolates (42.5%). The most frequently isolated MDR bacteria in patients with HAI were extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli (n = 1216/3223, 37.7%), MDR Pseudomonas aeruginosa (n = 627/3223, 19.5%) and MDR Acinetobacter baumannii (n = 588/3223, 18.2%). MDR-HAI were more common in males (2074/3223, 64.4%) and in elderly patients (≥60 years; 1196/3223, 37.1%). Sputum was the main source of MDR isolates (2056/3223, 63.8%). Patients with MDR-HAI were predominantly distributed in different types of intensive care units. MDR strains in our study showed resistance to most current antibiotics. Overall, patients with HAI infections attributed to MDR bacteria were widely distributed in our hospital. Enhanced surveillance of MDR bacteria is critical for guiding the rational use of antibiotics and reducing the incidence of HAI.

FIGURE 1

Susceptibility rates of MDR strains isolated from patients with HAI. A) The susceptibility of MRSA isolates to vancomycin, tigecycline, and linezolid was 100%. B) The susceptibility rate of ESBLECO isolates to imipenem, ertapenem, piperacillin/tazobactam, and cefotetan was above 90%. C) ESBLKPN isolates were highly susceptible to amikacin (100%), ceftriaxone (98.5%), ertapenem (94.1%), and imipenem (91.2%). D) MDRPA isolates showed high susceptibility to amikacin (84.7%), tobramycin (78.5%), and gentamicin (70.8%). E) MDRAB isolates were susceptible to minocycline (94.2%) and amikacin (56.7%). F) CRKPN isolates were susceptible to amikacin (60%) and levofloxacin (53.3%). G) CRECO isolates were susceptible to nitrofurantoin (66.7%) and trimethoprim/sulfamethoxazole (66.7%). *The susceptibility testing was not performed for VREFM and VREFA due to a very small number of resistant strains. MDR: Multidrug resistant; HAI: Hospital-acquired infection; MRSA: Methicillin-resistant Staphylococcus aureus; MDRPA: Multidrug-resistant Pseudomonas aeruginosa; MDRAB: Multidrug-resistant Acinetobacter baumanii; ESBLECO: Extended-spectrum beta-lactamase-producing Escherichia coli; CRECO: Carbapenem-resistant Escherichia coli; ESBLKPN: Extended-spectrum beta-lactamase-producing Klebsiella pneumoniae; CRKPN: Carbapenem-resistant Klebsiella pneumoniae; VREFM: Vancomycin-resistant Enterococcus faecium; VREFA: Vancomycin-resistant Enterococcus faecalis.