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Updated: Feb 1, 2026
Invasion of Human Cells by a Bacterial Pathogen
Published on: March 21, 2011
Antimicrobial resistance in bacterial pathogens among hospitalised patients with severe invasive infections
Ovidiu Zlatian1, Andrei Theodor Balasoiu2, Maria Balasoiu1
1Department of Microbiology, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania.
Abstract:
The most severe infections are invasive infections, due to the fact that the germs can accumulate in multiple sites and produce a body-wide infection known as sepsis. Septic shock has the highest mortality rate among non-traumatic medical conditions. In this study, we aimed to evaluate the incidence and prevalence of invasive infections in a hospital environment. Another second objective was to establish the aetiology of invasive infections in our hospital and the antibiotic resistance profile of the germs involved, which are both important for determining the therapeutic approach for the treatment of these infections. The study included 505 hospitalized patients from which we collected a total of 974 blood cultures. For the analysis of the blood cultures, we used an automated incubator. The bottles flagged as positive were subcultured on blood agar, and the grown colonies were identified using an identification system. Invasive infections had a prevalence rate of 27.72% in our hospital. From the 974 blood cultures, we isolated 170 bacterial strains: Staphylococcus aureus (SA; 63 strains, 37.06%), Klebsiella spp. (27 strains, 15.88%), coagulase-negative staphylococci (CoNS; 18 strains, 10.59%), Enterococcus spp. (17 strains, 10.00%), Escherichia coli (12 strains, 7.06%), Streptococcus spp. (11 strains, 6.47%) and other bacterial species. The prevalence of methicillin-resistant SA (MRSA) in our study was 36.51% from the SA strains. The MRSA prevalence differed significantly according to age (37.50% in adults vs. 28.57% in children, P=0.047) and ICU admission (42.42% in ICU patients vs. 30.00% in non-ICU patients, P=0.018). We performed a multivariate analysis of the invasive infection risk which detected as significant predictors the admission into the cardiology ward and plastic surgery ward. On the whole, the findings of this study indicate that the high prevalence of Gram-positive cocci in blood cultures, mostly SA, with multidrug resistance has important consequences for the management of invasive infections.
Insights
Invasive infections, particularly sepsis, are a major concern. This study found a 27.72% prevalence of invasive infections, with Staphylococcus aureus being the most common pathogen, often resistant to antibiotics.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Hospital Epidemiology
Background:
- Invasive infections, including sepsis and septic shock, pose significant mortality risks.
- Understanding the incidence, prevalence, and etiology of these infections is crucial for effective treatment strategies.
Purpose of the Study:
- To determine the incidence and prevalence of invasive infections in a hospital setting.
- To identify the etiological agents responsible for invasive infections and their antibiotic resistance profiles.
- To inform therapeutic approaches for managing invasive infections.
Main Methods:
- Analysis of 974 blood cultures from 505 hospitalized patients.
- Utilized automated incubation and subculturing on blood agar for bacterial isolation.
- Employed an identification system for bacterial strain characterization.
- Performed multivariate analysis to identify risk factors for invasive infections.
Main Results:
- Invasive infections were prevalent in 27.72% of patients.
- Staphylococcus aureus (SA) was the most frequently isolated bacterium (37.06%), followed by Klebsiella spp. (15.88%).
- Methicillin-resistant Staphylococcus aureus (MRSA) accounted for 36.51% of SA strains, with higher prevalence in adults and ICU patients.
- Cardiology and plastic surgery ward admissions were significant predictors of invasive infection risk.
Conclusions:
- Gram-positive cocci, predominantly Staphylococcus aureus, are common in blood cultures.
- High rates of multidrug resistance, particularly MRSA, present challenges for invasive infection management.
- Findings underscore the need for targeted antibiotic strategies and infection control measures.
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