Severe infections caused by multidrug-resistant non-fermentative bacilli in southern Poland
Agnieszka Chmielarczyk1, Monika Pobiega1, Grzegorz Ziółkowski2
1Chair of Microbiology, Jagiellonian University Medical College, Kraków, Poland.
Background:
The impact of multidrug-resistant organisms (MDROs), including non-fermentative bacilli (NFBs), is rising and underestimated, especially in intensive care units (ICUs). The growing prevalence of multidrug resistance (MDR) and extensive drug resistance (XDR) is challenging for clinicians, as the treatment options are limited.
Objectives:
The purpose of this study was to analyze the extent of the epidemiological problem of multidrugresistant, extensively drug-resistant and pandrug-resistant (PDR) non-fermentative bacilli isolated from pneumonia and bloodstream infections (BSIs) in patients hospitalized in southern Poland.
Material And Methods:
This study included 253 NFBs belonging to Acinetobacter sp. (ACI), Pseudomonas sp. (PAR), and Stenotrophomonas sp. (STM). The microorganisms were identified, and susceptibility testing was performed using a semi-automatic system. The different patterns of resistance were defined as MDR, XDR, or PDR strains. Epidemiological typing of A. baumannii from ICUs was performed by repetitive polymerase chain reaction (rep-PCR).
Results:
More than half of the strains (57.7%) were isolated within ICUs. ACI-strains came significantly more often from ICU wards. The highest prevalence of ACI and PAR was found in pneumonia, whereas STM dominated in BSIs. ACIs were more frequently resistant than other pathogens to all studied antibiotics except colistin (n = 76; 58.9%), and they belonged to the XDR category. DiversiLab demonstrated the presence of 2 dominant clones in the ACI group, both classified as European Clone 2 (EUII).
Conclusions:
Our results indicate serious potential therapeutic problems related to high antibiotic resistance of ACI isolates. The stratification of drug resistance (MDR/XDR/PDR) may become an important tool for the assessment of public health epidemiology and microbiological hazards at the local, national, and international level. It allows clear presentation of the issues concerning the epidemiology of highly resistant bacilli, and the exchange of information between medical staff and local representatives of public health for the implementation of effective measures to reduce drug resistance.
Insights
Multidrug-resistant non-fermenting bacilli (NFBs), particularly Acinetobacter sp. (ACI), pose a significant threat in intensive care units (ICUs). High rates of extensive drug resistance (XDR) in ACI highlight urgent therapeutic challenges and the need for enhanced surveillance.
Area of Science:
- Microbiology
- Infectious Diseases
- Public Health
Background:
- Rising prevalence of multidrug-resistant organisms (MDROs), including non-fermentative bacilli (NFBs), poses a significant challenge in healthcare settings, particularly intensive care units (ICUs).
- Increasing rates of multidrug resistance (MDR) and extensive drug resistance (XDR) among pathogens limit effective treatment options for clinicians.
- Non-fermenting bacilli are increasingly implicated in hospital-acquired infections, necessitating a deeper understanding of their resistance patterns.
Purpose of the Study:
- To analyze the epidemiological burden of multidrug-resistant, extensively drug-resistant, and pandrug-resistant (PDR) non-fermentative bacilli (NFBs).
- To investigate NFBs isolated from pneumonia and bloodstream infections (BSIs) in hospitalized patients in southern Poland.
- To characterize the resistance profiles and clonal dissemination of key NFB species.
Main Methods:
- Analysis of 253 NFB isolates, including Acinetobacter sp. (ACI), Pseudomonas sp. (PAR), and Stenotrophomonas sp. (STM).
- Microorganism identification and antimicrobial susceptibility testing using a semi-automatic system.
- Classification of strains into MDR, XDR, or PDR categories; epidemiological typing of Acinetobacter baumannii using repetitive PCR (rep-PCR).
Main Results:
- Over half (57.7%) of NFB strains were isolated from ICUs, with Acinetobacter sp. (ACI) predominantly found in these wards.
- ACI and Pseudomonas sp. (PAR) were most prevalent in pneumonia, while Stenotrophomonas sp. (STM) dominated bloodstream infections (BSIs).
- ACI strains exhibited high resistance to most tested antibiotics, frequently falling into the XDR category, with two dominant European Clone 2 (EUII) clones identified.
Conclusions:
- High antibiotic resistance in Acinetobacter sp. (ACI) isolates presents significant therapeutic challenges.
- Stratification of drug resistance (MDR/XDR/PDR) is crucial for assessing public health and microbiological risks.
- Effective communication and data exchange on highly resistant bacilli are essential for implementing targeted interventions to combat antimicrobial resistance.
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