Extensive Drug Resistance of Strong Biofilm-Producing Acinetobacter baumannii Strains Isolated from Infections and Colonization Hospitalized Patients in Southern Poland.

Acinetobacter baumannii (AB) is a bacterium that causes infections, particularly in immunocompromised patients. Treatment is challenging due to biofilm formation by AB strains, which hinders antibiotic effectiveness and promotes drug resistance. The aim of our study was to analyze the biofilm-producing capacity of AB isolates from various forms of infections in relation to biofilm-related genes and their drug resistance. We tested one hundred isolates for biofilm formation using the crystal violet microplate method. Drug resistance analyses were performed based on EUCAST and CLSI guidelines, and biofilm genes were detected using PCR. All tested strains were found to form biofilms, with 50% being ICU strains and 72% classified as strong biofilm producers. Among these, 87% were extensively drug-resistant (XDR) and 2% were extra-extensively drug-resistant (E-XDR). The most common gene set was bap, bfmS, csuE, and ompA, found in 57% of all isolates. Our research shows that, regardless of the form of infection, biofilm-forming strains can be expected among AB isolates. The emergence of E-XDR and XDR strains among non-ICU infections highlights the necessity for the rational use of antibiotics to stop or limit the further acquisition of drug resistance by A. baumannii.

Antimicrobial Resistance of Enterobacteriaceae in Bloodstream Infections in Hospitalized Patients in Southern Poland.

Aim: The aim of this study was to highlight antimicrobial resistance among Enterobacteriaceae isolated from bloodstream infections in hospitals in southern Poland. Materials and Methods: The present study includes laboratory-confirmed secondary bloodstream infections (LC-BSIs), in the years 2015-2018, in hospitalized adult patients (≥18). Episodes of BSIs were defined according to the strictly described guidelines. Antimicrobial susceptibility testing was performed with the automated system and the disc diffusion method. Extended-spectrum ß-lactamases (ESBLs)-producing Enterobacteriaceae were detected using the double-disc synergy test. Results: Between 2015 and 2018, 356 episodes of secondary BSIs in 997 patients aged 21-96 years were documented in a prospective study, including 134 (37.6%) ESBL-producing Enterobacteriaceae. Escherichia coli was the predominant pathogen in internal medicine (37.6%) and surgery units (46.8%); in intensive care units (ICUs), Klebsiella pneumoniae was isolated more frequently (33.3%). Enterobacteriaceae were highly resistant to most antimicrobial agents. K. pneumoniae isolates had a higher level of resistance than E. coli, regardless of the unit. Conclusions: The increase in AMR and the widespread distribution of ESBL-producing Enterobacteriaceae in Polish hospitals can be related to the lack of or inappropriate antibiotic treatment.

Virulence and Drug-Resistance of Staphylococcus aureus Strains Isolated from Venous Ulcers in Polish Patients.

Infected chronic venous ulcers (VUs) represent a major health problem. We analysed the aerobic microbiome in the VUs, the virulence, and drug-resistance of Staphylococcus aureus (SA) strains. Swabs from 143 outpatients and inpatients Polish subjects were collected. SA strains were tested for drug sensitivity using a phenotyping method and for methicillin-resistant SA (MRSA) and macrolide-lincosamide-streptogramin B (MLSB) resistance using PCR. We analysed virulence genes, the genetic similarity of strains, and performed Staphylococcal cassette chromosome mec typing and Staphylococcal protein A typing. SA was isolated as a single one in 34.9% of cases, 31.5% paired with another pathogen, and 33.6% S. aureus combined with at least two other strains. The majority of SA isolates (68.5%) possessed the virulence lukE gene. Drug resistance was significantly common in hospitalised than in ambulatory patients (OR 3.8; 95%CI 1.8-7.91). MLSB (altogether in 19.6% isolates) were observed mostly in non-hospitalised patients (OR 9.1; 95%CI 1.17-71.02), while MRSA was detected in 11.9% of strains equally. Hospitalisation and patient's age group (aged > 78.0 or < 54.5 years) were significant predictors of the multi-drug resistant SA (MDR-SA). Over 30% of the infected VUs were associated with multi-species biofilms and presence of potentially highly pathogenic microorganisms. Elderly hospitalised patients with chronic venous ulcers are prone to be infected with a MDR-SA.

Healthcare-Associated Laboratory-Confirmed Bloodstream Infections-Species Diversity and Resistance Mechanisms, a Four-Year Retrospective Laboratory-Based Study in the South of Poland.

INTRODUCTION: Regardless of the country, advancements in medical care and infection prevention and control of bloodstream infections (BSIs) are an enormous burden of modern medicine. OBJECTIVES: The aim of our study was to describe the epidemiology and drug-resistance of laboratory-confirmed BSI (LC-BSIs) among adult patients of 16 hospitals in the south of Poland. PATIENTS AND METHODS: Data on 4218 LC-BSIs were collected between 2016-2019. The identification of the strains was performed using MALDI-TOF. Resistance mechanisms were investigated according to European Committee on Antimicrobial Susceptibility Testing, EUCAST recommendations. RESULTS: Blood cultures were collected from 8899 patients, and LC-BSIs were confirmed in 47.4%. The prevalence of Gram-positive bacteria was 70.9%, Gram-negative 27.8% and yeast 1.4%. The most frequently isolated genus was Staphylococcus (50% of all LC-BSIs), with a domination of coagulase-negative staphylococci, while Escherichia coli (13.7%) was the most frequent Gram-negative bacterium. Over 4 years, 108 (2.6%) bacteria were isolated only once, including species from the human microbiota as well as environmental and zoonotic microorganisms. The highest methicillin resistant Staphylococcus aureus (MRSA) prevalence was in intensive care units (ICUs) (55.6%) but S. aureus with resistance to macrolides, lincosamides and streptogramins B (MLSB) in surgery was 66.7%. The highest prevalence of E. faecalis with a high-level aminoglycoside resistance (HLAR) mechanism was in ICUs, (84.6%), while E. faecium-HLAR in surgery was 83.3%. All cocci were fully glycopeptide-sensitive. Carbapenem-resistant Gram-negative bacilli were detected only in non-fermentative bacilli group, with prevalence 70% and more. CONCLUSIONS: The BSI microbiology in Polish hospitals was similar to those reported in other studies, but the prevalence of MRSA and enterococci-HLAR was higher than expected, as was the prevalence of carbapenem-resistant non-fermentative bacilli. Modern diagnostic techniques, such as MALDI-TOF, guarantee reliable diagnosis.

Prevalence and Antimicrobial Susceptibility Profiles of Microorganisms Associated with Lower Reproductive Tract Infections in Women from Southern Poland-Retrospective Laboratory-Based Study.

OBJECTIVE: Female infections affecting the genital tract include sexually transmitted diseases, endogenous infections such as vulvovaginal candidiasis, bacterial vaginosis (BV) or aerobic vaginitis (AV) and healthcare-associated infections. The aim of the study was to analyze the etiological factors of the vaginal dysbacteriosis, and the antimicrobial susceptibility of the dominant bacterial and fungal infections in different age groups of outpatient women from the Silesian Region. MATERIALS AND METHODS: A retrospective laboratory-based multi-center study encompassed 4994 women of different ages in Silesian Voivodeship, in the south of Poland; patients who had vaginal swabs collected as per physicians' orders during the period from 1 January 2017 until 30 June 2018 were included in the study. The inclusion criteria were: non-hospitalized female, aged ≤80, with suspected vulvovaginal candidiasis or bacterial vaginosis and clinical sings of infections. RESULTS: Gram-positive cocci were the ones most often isolated: Enterococcus faecalis (29.2%) and Streptoccoccus agalactiae (13.1%), followed by bacilli from the Enterobacteriaceae group, including Escherichia coli (26.3%). The presence of Streptococcus agalactiae was confirmed in 13.1%, slightly more often in the 45-80 age group, and Gardnerella vaginalis in 6.4%, most often in women aged 15-24. The prevalence of yeast-like infections was 24.3%, Candida albicans accounted for 78.3%, whereas among C. non-albicans spp.-C. glabrata dominated (14.9%) followed by C. parapsilosis (3.8%). The highest resistance was observed only in Streptococcus agalactiae as the MLSB mechanism (Macrolide-lincosamide-streptogramin B) was identified in 38.6% of strains. The prevalence of vulvovaginal candidiasis was 24.3%, the highest in women aged 15-44. CONCLUSIONS: Drug resistance in studied vulvovaginitis was associated only with Streptococcus agalactiae. A high proportion of yeast-like aetiology was found, probably associated with recurrent infections. In the analyzed cases only the Amsel criteria and culture methods were used for diagnosis without preparations and microbiological Nugent criteria.

Epidemiology, Drug Resistance, and Virulence of Staphylococcus aureus Isolated from Ocular Infections in Polish Patients.

Analysis of the epidemiology of Staphylococcus aureus (SA) ocular infections and virulence factors of the isolates with a special emphasis on their drug resistance, and the ability of biofilm formation. In a period from 2009 to 2013, 83 isolates of SA were prospectively collected and preserved in a multicenter laboratory-based study carried out in southern Poland. Epidemiological, phenotypic, and genotypic analyses were performed. The resistance and virulence genes were analyzed. Screening for the biofilm formation was provided. Among the materials derived from ocular infections from 456 patients, SA was found in 18.2% (n = 83) of cases (one SA isolate per one patient). Most infections were identified in the age group of over 65 years (OR 8.4 95%CI; 1.03-68.49). The majority of patients (73.4%) were hospitalized. Among the virulence and resistance genes, the most frequently detected were the lukE (72.2%, n = 60) and ermA (15.6%, n = 13) genes. A positive result of the CRA test (the ability of biofilm formation) was found in 66.2% (n = 55) of isolates. Among the strains under study, 6.0% (n = 5) had the methicillin-resistant Staphylococcus aureus phenotype, and 26.5% (n = 22) had the macrolide-lincosamide-streptogramin B phenotype. In 48 (57.8%) isolates the neomycin resistance was revealed. All isolates under study were sensitive to vancomycin. The population most susceptible to ocular SA infections consists of hospitalized patients aged 65 and more. The SA strains under study showed the increased ability to biofilm formation. In the strains tested, high susceptibility to chloramphenicol and fluoroquinolones was demonstrated. However, the high level of drug resistance to neomycin detected in this study among SA isolates and the blood-ocular barrier makes it difficult to treat ocular infections.Analysis of the epidemiology of Staphylococcus aureus (SA) ocular infections and virulence factors of the isolates with a special emphasis on their drug resistance, and the ability of biofilm formation. In a period from 2009 to 2013, 83 isolates of SA were prospectively collected and preserved in a multicenter laboratory-based study carried out in southern Poland. Epidemiological, phenotypic, and genotypic analyses were performed. The resistance and virulence genes were analyzed. Screening for the biofilm formation was provided. Among the materials derived from ocular infections from 456 patients, SA was found in 18.2% (n = 83) of cases (one SA isolate per one patient). Most infections were identified in the age group of over 65 years (OR 8.4 95%CI; 1.03-68.49). The majority of patients (73.4%) were hospitalized. Among the virulence and resistance genes, the most frequently detected were the lukE (72.2%, n = 60) and ermA (15.6%, n = 13) genes. A positive result of the CRA test (the ability of biofilm formation) was found in 66.2% (n = 55) of isolates. Among the strains under study, 6.0% (n = 5) had the methicillin-resistant Staphylococcus aureus phenotype, and 26.5% (n = 22) had the macrolide-lincosamide-streptogramin B phenotype. In 48 (57.8%) isolates the neomycin resistance was revealed. All isolates under study were sensitive to vancomycin. The population most susceptible to ocular SA infections consists of hospitalized patients aged 65 and more. The SA strains under study showed the increased ability to biofilm formation. In the strains tested, high susceptibility to chloramphenicol and fluoroquinolones was demonstrated. However, the high level of drug resistance to neomycin detected in this study among SA isolates and the blood-ocular barrier makes it difficult to treat ocular infections.

Antimicrobial resistance of Escherichia coli isolates from outpatient urinary tract infections in women in six European countries including Russia.

OBJECTIVES: In the Northern Dimension Antibiotic Resistance Study (NoDARS), Finland, Germany, Latvia, Poland, Russia and Sweden collected urine samples from outpatient women (aged 18-65years) with symptoms of uncomplicated urinary tract infection (UTI) to investigate the levels of antimicrobial resistance (AMR) among Escherichia coli isolates. METHODS: A total of 775 E. coli isolates from 1280 clinical urine samples were collected from October 2015 to January 2017. Antimicrobial susceptibility testing was performed and the results were interpreted according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) criteria. RESULTS: Overall AMR rates to the commonly used antibiotics nitrofurantoin, fosfomycin and mecillinam (except for Germany that was missing a result for mecillinam) were 1.2%, 1.3% and 4.1%, respectively. The highest overall resistance rates were determined for ampicillin (39.6%), trimethoprim (23.8%), trimethoprim/sulfamethoxazole (22.4%), amoxicillin/clavulanic acid (16.7%) and ciprofloxacin (15.1%), varying significantly between countries. The rate of extended-spectrum ß-lactamase (ESBL) production was 8.7%. None of the isolates showed resistance to meropenem. CONCLUSIONS: In most cases, low AMR rates were detected against the first-line antibiotics recommended in national UTI treatment guidelines, giving support to their future use. These results also support the European Association of Urology guidelines stating that nitrofurantoin, fosfomycin and mecillinam are viable treatment options for uncomplicated UTI.

Large variation in ESBL-producing Escherichia coli carriers in six European countries including Russia.

We investigated the faecal carriage prevalence of extended-spectrum ß-lactamase production in Escherichia coli (EP-EC) and/or Klebsiella pneumoniae (EP-KP) and risk factors associated with carriage among adult study subjects in Finland, Germany, Latvia, Poland, Russia and Sweden (partner countries). The aim was to get indicative data on the prevalence of ESBL-carriage in specific populations in the region. Faecal samples were collected from four study populations and screened on ChromID-ESBL and ChromID-OXA-48 plates. Positive isolates were further characterised phenotypically. Our results show a large variation in carrier prevalence ranging from 1.6% in Latvia to 23.2% in Russia for EP-EC. For the other partner countries, the prevalence of EP-EC were in increasing numbers, 2.3% for Germany, 4.7% for Finland, 6.6% for Sweden, 8.0% for Poland and 8.1% for all partner countries in total. Carriers of EP-KP were identified only in Finland, Russia and Sweden, and the prevalence was < 2% in each of these countries. No carriers of carbapenemase-producing isolates were identified. This is the first study reporting prevalence of carriers (excluding traveller studies) for Finland, Latvia, Poland and Russia. It contributes with important information regarding the prevalence of EP-EC and EP-KP carriage in regions where studies on carriers are limited.

Severe infections caused by multidrug-resistant non-fermentative bacilli in southern 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.

Virulence and antimicrobial resistance of Staphylococcus aureus isolated from bloodstream infections and pneumonia in Southern Poland.

OBJECTIVES: Staphylococcus aureus remains the most important cause of infections in hospitals and long-term care facilities. The aim of this study was to analyse the resistance, virulence, and epidemiological and genetic relationships of S. aureus from bloodstream infections (BSIs) and pneumonia from patients in Southern Poland. METHODS: All strains were tested for antimicrobial susceptibility using the disk diffusion method. Etest was also performed for vancomycin, teicoplanin, tigecycline, oxacillin, cefoxitin and penicillin. PCR amplification was used to detect selected virulence genes. The genetic similarity of methicillin-resistant S. aureus (MRSA) isolates was determined by spa typing and pulsed-field gel electrophoresis (PFGE). Using the BURP algorithm and the Ridom SpaServer database, spa types were clustered into different clonal complexes (spa-CCs). RESULTS AND CONCLUSIONS: MRSA strains were observed at a prevalence of 26.7%, but 88.6% of hospital-acquired infections were MRSA, with no difference between BSIs and pneumonia. The highest resistance was observed to erythromycin and tobramycin. None of the strains were resistant to linezolid, glycopeptides or tigecycline. The strains had no significant virulence factors and the number of virulence genes present did not correlate with the degree of drug resistance. PFGE typing showed relatively high diversity of strains. The majority of isolates belonged to spa type t003 (CC5).

Longevity and gender as the risk factors of methicillin-resistant Staphylococcus aureus infections in southern Poland.

BACKGROUND: The proportion of older people among the general population has risen. Staphylococcus aureus (SA) constitutes a significant problem. Underlying disease and functional debility, predispose the older adult to staphylococcal carriage and infection, specially bloodstream infection and pneumonia. METHODS: This is a retrospective cohort study of older patients with SA infections. We analyzed a database containing the results of laboratory cultures from patients treated in 2013 for SA infections and selected 613 hospitalized and non-hospitalized people aged ≥60 years. RESULTS: The prevalence of Methicillin-resistant SA (MRSA) were significantly different in categories of patients: from 14.1% in young old, 19.5% in old old and 26.7 in longevity. MRSA was significantly more frequently reported in cases of pneumonia, 40.4% of SA strains (p < 0.0001, OR 0.3, 95%CI 0.14-0.49). The nosocomial MRSA infections were more common in ICU departments: prevalence 36.8%, than in non-ICU departments: prevalence 17.3% (OR 2.8, 95%CI 1.06-7.34, p = 0.014). Bloodstream infections, which accounted for 6% of all infections, were more frequent in males (p = 0.0231, OR 2.25, 95%CI 1.098-4.604). The greatest increase in antibiotic resistance was related to trimethoprim/sulfamethoxazole (TMP/SXT), which increased to over 80% in the older study groups. All age groups demonstrated increased MIC90 values for glycopeptide and tigecycline. Although strains isolated from patients in all age groups remained sensitive to vancomycin, strains isolated from patients in the old-old and longevity groups demonstrated resistance to teicoplanin. The MIC90 for tigecycline was the highest in the group aged >90 years. CONCLUSIONS: MRSA constitutes a significant epidemiological problem in cases of hospital-treated pneumonia. The findings were similar for long-term-care facilities, where MRSA appears to affect male residents in particular, although there were fewer male residents than female residents. The low sensitivity to TMP/SXT of SA strains isolated from the oldest patients indicates potentially serious challenges pertaining to efficacious treatment of SA infections.

[Molecular characterization of Staphylococcus aureus strains isolated from surgical site infections of patients in southern Poland].

INTRODUCTION: The aim of the study was a molecular characterization of Staphylococcus aureus strains isolated from surgical site infections (SSIs) from patients in southern Poland, undergoing different surgical procedures, together with evaluation of the prevalence of antimicrobial resistance and the presence of virulence factors. MATERIALS AND METHODS: In this laboratory-based, multicenter study, non-repetitive 162 samples from SSI were collected from hospitalized patients (12 hospitals, n=139) or outpatients (n=23) in southern Poland between January 1 and December 31, 2013. In all S. aureus isolates, we investigated antimicrobial susceptibility, the presence of selected virulence genes (lukE, pvl, tsst-l and eta), and also conducted spa typing. RESULTS: Patients with SSI had a median age of 61 years; 54.9% were male. Prevalence of MRSA (29 strains, 17.9%) SSI per surgery type was 8.7% in orthopaedic, 17.7% in general and 42.9% in vascular surgery. Over 20% of strains were resistant for erythromycin (27.2%), clindamycin (23.5%). No resistance was found for linezolid, glycopeptides or tigecycline. Gene of Leukocidin (lukE) was the most frequently found gene. Spa typing identified 10 spa types; the two dominant types were t003 (41.4%) and t138(17.2%). CONCLUSIONS: The results show that after vascular surgery, there was an unexpectedly high prevalence of MRSA in SSIs in southern Poland. Conversely, the prevalence of MRSA was unexpectedly low following orthopaedics procedures. The surprisingly observation was the low virulence of the S. aureus strains among older patients.

Virulence Potential of Staphylococcus aureus Strains Isolated from Diabetic Foot Ulcers Among Patients from Southern Poland.

The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) was investigated among infected diabetic foot ulcers in hospitalized and nonhospitalized patients in southern Poland to assess the virulence patterns and antimicrobial resistance among these strains. MRSA was detected in 10.3% of all studied isolates, from the hospitalized patients only. The rest of the isolates was methicillin susceptible. The minimal inhibitory concentration that inhibits 50% of bacterial isolates (MIC50) for vancomycin was 1.0 mg/mL. The mupA gene was detected in six (8.8%) isolates, in one MRSA strain and five methicillin-sensitive S. aureus (MSSA) strains. Among the mupA-positive strains, two were resistant to mupirocin (1 MRSA and 1 MSSA). Such results raise serious concern about the usage of mupirocin in MRSA decolonization. The pvl gene was not detected among the study isolates. The majority of isolates (70.6%) possessed the lukE gene, with no significant difference in prevalence between MRSA and MSSA isolates. An interesting finding was the presence of enterotoxin genes among the study isolates. Diabetic foot may therefore be a reservoir of bacteria, containing genes localized on mobile genetic elements that could be easily transferred to other non-pathogenic strains. The prevalence of MRSA was alarmingly high (as also suggested by others), as evaluated by the presence of the mup gene among strains, highlighting the importance of appropriate clinical management of MRSA infections in patients with diabetic foot ulcers. In this group of patients, screening of ulcer samples before antimicrobial therapy would enable informed choices regarding the selection of antimicrobial agents (e.g. octenidine, authorized for the treatment of chronic wounds) maximizing the chances of positive therapy.

Molecular characterization of carbapenem-resistant Pseudomonas aeruginosa strains isolated from patients with urinary tract infections in Southern Poland.

Due to the clinical threat posed by multidrug-resistant (MDR) Pseudomonas aeruginosa and importance of virulence factors produced in infection, 21 carbapenem-resistant P. aeruginosa were analyzed. 42.8% metallo-beta-lactamases-positive strains were identified. 85.7% of strains were meropenem resistant. 14.2% of strains were MDR; 38%, extensively drug-resistant (XDR). ExoY was present in all strains; exoT, in 95.2%; exoS, in 90.5%; exoU, in 47.6%. Eight XDR strains were typed using multilocus sequence typing: 4 as ST235, 2 as ST260, 2 as ST654 and ST234. MDR P. aeruginosa were isolated from hospitalized patients and among those from the community. Our study demonstrates the serious clinical issues posed by MDR P. aeruginosa and underscores the need for new treatment.

Virulence and Antibiotic Resistance of Pseudomonas aeruginosa Isolated from Patients with Urinary Tract Infections in Southern Poland.

BACKGROUND: The aim of this study was to analyze the resistance and virulence of Pseudomonas aeruginosa strains causing urinary tract infections in in- and outpatients in Southern Poland. METHODS: The study included 83 inpatients and 66 outpatients; 36.9% were female. RESULTS: Monomicrobial infections accounted for 74.5%; polymicrobial infections occurred more frequently among inpatients (odds ratio, OR = 4.32, p = 0.0008). exoS and lasB were detected in 90 and 74% of isolates, respectively. aprA was present in 66%, pilB in 5% and pilA in 23% of isolates. Isolates from adults were more frequently resistant to fluoroquinolones (OR = 0.37, p = 0.029). Twenty-nine isolates were classified as multidrug resistant and 12 as extremely drug resistant, which occurred less frequently in patients <17 years (OR = 0.18, p = 0.024). Nine metallo-ß-lactamase-positive isolates were identified. blaSHV was present in 10, blaTEM in 6, blaOXA-10 in 3 and blaVIM-2 in 3 isolates. CONCLUSION: Antibiotic selection should be based on the knowledge of local antimicrobial susceptibilities to maximize the benefit for patients and minimize the risk of drug resistance.