Changes in Antibiotic Resistance of Acinetobacter baumannii and Pseudomonas aeruginosa Clinical Isolates in a Multi-Profile Hospital in Years 2017-2022 in Wroclaw, Poland.

In recent years, we have witnessed increasing drug resistance among bacteria, which is associated with the use and availability of an increasing number of broad-spectrum antimicrobials, as well as with their irrational and excessive use. The present study aims to analyze changes in the drug resistance of Gram-negative Pseudomonas aeruginosa and Acinetobacter baumannii, isolated from infections in a multi-profile hospital over a five-year period (from 2017 to 2022). Among the practical results of the evaluation of these data will be the possibility to determine changes in susceptibility to the antibiotics used in the hospital. This, in turn, will help propose new therapeutic options, especially for empirical therapy, which is essential in severe infections. Analysis of the use of different antibiotic groups has made it possible to identify the causes of increasing resistance in the analyzed Gram-negative bacilli. The highest antibiotic use was observed in the hospital between 2020 and 2022, most probably due to the COVID-19 pandemic and the higher number of patients in severe condition requiring hospitalization. Unfortunately, during the period analyzed, the number of multi-resistant strains of A. baumannii was successively increasing; this seems to be related to the increased use, especially during the pandemic period, of broad-spectrum antibiotics, mainly penicillins with inhibitors, third-generation cephalosporins and carbapenems.

Reliability of E-Tests and the Phoenix Automated Method in Assessing Susceptibility to IV Fosfomycin-Comparative Studies Relative to the Reference Method.

The agar dilution method (ADM) recommended for IV fosfomycin (IV FOS) is complex and labor-intensive. Keeping in mind the reality of everyday laboratory work, we have evaluated the agreement of IV FOS susceptibility results obtained using the E-test and the Phoenix system with the results obtained using the ADM. MATERIALS AND METHODS: The tests were performed on 860 strains. To evaluate susceptibility to IV FOS, BioMerieux E-tests (bioMerieux, Warsaw, Poland), BD Phoenix panels (BD Phoenix, Sparks, MD, USA), and the ADM were used. Clinical interpretation was performed in accordance with EUCAST Guidance (v12.0, 2021). The significance of the E-test and the Phoenix was analyzed in relation to the ADM by defining categorical agreement (CA), major error (ME), and very major error (VME). Essential agreement (EA) has also been defined for the E-test. A method was considered reliable, in accordance with ISO 20776-2:2007, when CA and EA were above 89.9% and VME was <3%. RESULTS: A categorical agreement of >98.9% was demonstrated between the E-test and the ADM for overall strains and for Echerichia coli, ESBL-producing Enterobacterales, and Staphylococcus aureus, while between the Phoenix and the ADM, a CA of >98.9% was shown only for Escherichia coli, Staphylococcus aureus, and Proteus spp. A very major error rate of <3% was obtained only for Staphylococcus aureus and MBL-producing Pseudomonas evaluated by both the E-test and the Phoenix. An essential agreement of >98.9% between the E-test and the ADM has not been demonstrated for any of the tested groups of strains. The Phoenix yielded more VMEs than the E-test (50 and 46, respectively). The highest VME rate was demonstrated using the Phoenix method for Enterobacter spp. (53.83%). CONCLUSIONS: Both the E-test and the Phoenix have turned out to be reliable in assessing IV FOS susceptibility only for Staphylococcus aureus (CA > 89.9% and VME < 3%). For the remaining tested groups of strains and genera, the simultaneous high CA rate and low VME rate required by ISO were not achieved. Both methods fared particularly badly in detecting strains resistant to IV.

Evolution of Antibiotic Resistance in Escherichia coli and Klebsiella pneumoniae Clinical Isolates in a Multi-Profile Hospital over 5 Years (2017-2021).

In recent years, we have witnessed a growing drug resistance among bacteria, which is associated with the use and availability of an increasing number of broad-spectrum antimicrobial agents, as well as with their irrational and excessive use. The present study aims to analyze changes in the drug resistance of Gram-negative Enterobacterales: Escherichia coli and Klebsiella pneumoniae, isolated from infections in a multi-profile hospital over five years (from 2017 to 2021). Among the practical outcomes of the evaluation of these data will be the possibility of determining changes in susceptibility to the antibiotics used in the hospital. In turn, this will help propose new therapeutic options, especially for empirical therapy that is necessary in severe infections. The analysis of the use of individual groups of antibiotics allowed for identification of the causes of the increasing resistance of Gram-negative bacilli. The highest number of infections whose etiological agent was K. pneumoniae ESBL(+) and E. coli ESBL(+) was observed in 2018. In the analyzed five-year period, the number of multi-resistant (MDR) K. pneumoniae strains increased successively, which seems to be related to the growing use, especially in the pandemic period, of broad-spectrum antibiotics, mainly penicillins with inhibitors, third-generation cephalosporins, and carbapenems.

Assessment of the Susceptibility of Clinical Gram-Negative and Gram-Positive Bacterial Strains to Fosfomycin and Significance of This Antibiotic in Infection Treatment.

Multidrug resistance of bacteria has prompted intensive development work on new medicines, but also the search for effective options among the oldest antibiotics. Although intravenous fosfomycin (IVFOS) seems to be an interesting proposal, the recommended agar dilution method for susceptibility determination poses a major problem in routine diagnostic testing. As a consequence, there is a lack of comprehensive data on the frequency of isolation of susceptible or resistant strains. This fact triggered the disposition of EUCAST concerning the revision of IVFOS breakpoints (BPs), including withdrawal of BPs for Enterobacterales (excluding E. coli) and coagulase-negative staphylococci. Therefore, the aim of this study was to assess the activity of fosfomycin against numerous clinical strains using recommended methods. Materials and methods: A total of 997 bacterial strains were tested from the following genera: Enterobacterales, Pseudomonas spp., Staphylococcus spp., Acinetobacter spp., and Enterococcus spp., for which there are currently no BPs. The strains were isolated from various clinical materials from patients hospitalized in five hospitals. During the investigation, the recommended agar dilution method was used. Susceptibility to other antibiotics and resistance mechanisms were determined using an automatic method (Phoenix) the disk diffusion method, and E-tests. MIC values of fosfomycin were estimated for all strains and for susceptible and multidrug-resistant (MDR) strains individually. Results: Except for Acinetobacter and Enterococcus, 83% of the strains were susceptible to IVFOS, including the largest percentage of S. aureus and E. coli. Klebsiella spp. turned out to be the least susceptible strains (66%). The highest proportion of susceptibility to fosfomycin was found among strains that were sensitive to other antibiotics (80.9%), and the lowest was found among Gram-negative carbapenemase-producing bacteria (55.6%) and ESBL+ bacteria (61.6%). The MIC evaluation revealed the lowest MIC50 and MIC90 values for S. aureus (0.5 mg/L and 1 mg/L, respectively) and E. coli (4 mg/L and 32 mg/L, respectively). The highest values of MIC50 were found for Acinetobacter spp. (256 mg/L), while the highest values of MIC90 were found for Acinetobacter spp. and Klebsiella spp. (256 mg/L and 512 mg/L, respectively). Conclusions: IVFOS appears to be suitable for the treatment of many infections, including the empirical treatment of polymicrobial infections and those caused by MDR strains, since the sensitivity of the studied strains to this antibiotic in different groups ranged from 66% to as much as 99%. Sensitivity to fosfomycin was also demonstrated by 60% of carbapenem-resistant strains; therefore, IVFOS is one of the few therapeutic options that can be effective against the most resistant Gram-negative rods. In light of the general consultation posted by EUCAST, obtaining data such as IVFOS MIC value distributions may be vital for the decision of implementing fosfomycin into breakpoint tables.

Occurrence and Characteristics of Carbapenem-Resistant Klebsiella pneumoniae Strains Isolated from Hospitalized Patients in Poland-A Single Centre Study.

The global emergence and spread of genes responsible for the production of ESBL (extended-spectrum beta-lactamases) and carbapenemases in Klebsiella pneumoniae isolates poses a serious threat to public health. The aim of this study was to retrospectively analyze the frequency of occurrence and drug resistance of selected alarm agents isolated from patients of the specialist hospital in Wroclaw. A total of 13,528 clinical materials collected from patients of a specialist hospital in Wroclaw were analyzed in the period from 1 January 2020 to 31 December 2020. Overall, 3894 bacterial strains were isolated from clinical materials, including 416 K. pneumoniae isolates. K. pneumoniae that showed resistance to ETP (ertapenem) and/or MEM (meropenem) were tested using phenotypic tests for the detection of KPC (carbapenemase-producing Klebsiella), MBL (metallo-ß-lactamase) and OXA-48 (oxacilinase-48) carbapenemases. In the case of a positive or doubtful result of the phenotypic test, immunochromatographic tests and the CarbaNP test were performed. In total, 58 K. pneumoniae isolates resistant to 1 or more carbapenem antibiotics were isolated. Of the 58 strains, 16 (27.6%) were isolated from rectal swabs conducted on CPE (carbapenemase-producing Enterobacteriaceae) carriers. In the case of CRE (carbapenem-resistant Enterobacteriaceae) K. pneumoniae, carbapenemases were detected in 28/58 (48.3%) isolates. Notably, 23/28 K. pneumoniae isolates produced MBL/NDM (New Delhi metallo-ß-lactamase) (82.1%), 5/28 produced VIM (Verona-intergon-encoded metallo-ß-lactamase) (14.3%), and one produced MBL/NDM + OXA-48. Carbapenemases were detected in 13 of 16 (81.3%) carbapenem-resistant K. pneumoniae isolates derived from rectal swabs. The significant participation of CRE and CPE isolates in the infections proves the need to test patients admitted to hospital wards for their status as a CPE carrier in order to limit the emergence of new epidemic outbreaks.

In Vitro Susceptibility of Multi-Drug Resistant Klebsiellapneumoniae Strains Causing Nosocomial Infections to Fosfomycin. A Comparison of Determination Methods.

INTRODUCTION: Over the past few decades, Klebsiella pneumoniae strains increased their pathogenicity and antibiotic resistance, thereby becoming a major therapeutic challenge. One of the few available therapeutic options seems to be intravenous fosfomycin. Unfortunately, the determination of sensitivity to fosfomycin performed in hospital laboratories can pose a significant problem. Therefore, the aim of the present research was to evaluate the activity of fosfomycin against clinical, multidrug-resistant Klebsiella pneumoniae strains isolated from nosocomial infections between 2011 and 2020, as well as to evaluate the methods routinely used in hospital laboratories to assess bacterial susceptibility to this antibiotic. MATERIALS AND METHODS: 43 multidrug-resistant Klebsiella strains isolates from various infections were tested. All the strains had ESBL enzymes, and 20 also showed the presence of carbapenemases. Susceptibility was determined using the diffusion method (E-test) and the automated system (Phoenix), which were compared with the reference method (agar dilution). RESULTS: For the reference method and for the E-test, the percentage of strains sensitive to fosfomycin was 65%. For the Phoenix system, the percentage of susceptible strains was slightly higher and stood at 72%. The percentage of fosfomycin-resistant strains in the Klebsiella carbapenemase-producing group was higher (45% for the reference method and E-test and 40% for the Phoenix method) than in carbapenemase-negative strains (25%, 25%, and 20%, respectively). Full (100%) susceptibility categorical agreement was achieved for the E-test and the reference method. Agreement between the automated Phoenix system and the reference method reached 86%. CONCLUSIONS: Fosfomycin appears to be the antibiotic with a potential for use in the treatment of infections with multidrug-resistant Klebsiella strains. Susceptibility to this drug is exhibited by some strains, which are resistant to colistin and carbapenems. The E-test, unlike the Phoenix method, can be an alternative to the reference method in the routine determination of fosfomycin susceptibility, as it shows agreement in terms of sensitivity categories and only slight differences in MIC values. The Phoenix system, in comparison to the reference method, shows large discrepancies in the MIC values and in the susceptibility category.

The In Vitro Ability of Klebsiella pneumoniae to Form Biofilm and the Potential of Various Compounds to Eradicate It from Urinary Catheters.

Urinary infections related to the presence of bacterial biofilm on catheters are responsible for loss of patients' health and, due to their high frequency of occurrence, generate a significant economic burden for hospitals. Klebsiella pneumoniae is a pathogen frequently isolated from this type of infection. In this study, using a cohesive set of techniques performed under stationary and flow conditions, we assessed the ability of 120 K. pneumoniae strains to form biofilm on various surfaces, including catheters, and evaluated the usefulness of clinically applied and experimental compounds to remove biofilm. The results of our study indicate the high impact of intraspecies variability with respect to K. pneumoniae biofilm formation and its susceptibility to antimicrobials and revealed the crucial role of mechanical flushing out of the biofilm from the catheter's surface with use of locally active antimicrobials. Therefore, our work, although of in vitro character, may be considered an important step in the direction of efficient reduction of K. pneumoniae biofilm-related hospital infections associated with the presence of urine catheters.

In vitro efficacy of gentamicin released from collagen sponge in eradication of bacterial biofilm preformed on hydroxyapatite surface.

Biofilm-related infections of bones pose a significant therapeutic issue. In this article we present in vitro results of the efficacy of gentamicin released from a collagen sponge carrier against Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella pneumoniae biofilms preformed on hydroxyapatite surface. The results indicate that high local concentrations of gentamicin released from a sponge eradicate the biofilm formed not only by gentamicin-sensitive strains but, to some extent, also by those that display a resistance pattern in routine diagnostics. The data presented in this paper is of high clinical translational value and may find application in the treatment of bone infections.

The Application of Impedance Microsensors for Real-Time Analysis of Pseudomonas aeruginosa Biofilm Formation.

Biofilms formed by nosocomial pathogens represent a major threat to patients undergoing invasive procedures. As prophylaxis remains the most efficient anti-biofilm option, it is of paramount importance to develop diagnostic tools able to detect biofilm at the early stage of formation. The present study investigates the ability of impedance microsensors to detect Pseudomonas aeruginosa biofilm presence using the impedance spectroscopy method. The measured data were analyzed using Electrical Equivalent Circuit modelling (EEC). It allowed to recognize conduction and polarization phenomena on the sensors surface and in its environment. The impedance assay results, confirmed by means of electron microscopy and quantitative cultures, indicate that specific EEC parameters may be used for monitoring the development of pseudomonal biofilm.

Rapid and specific detection, molecular epidemiology, and experimental virulence of the O16 subgroup within Escherichia coli sequence type 131.

Escherichia coli sequence type 131 (ST131), a widely disseminated multidrug-resistant extraintestinal pathogen, typically exhibits serotype O25b:H4. However, certain ST131 isolates exhibit serotype O16:H5 and derive from a phylogenetic clade that is distinct from the classic O25b:H4 ST131 clade. Both clades are assigned to ST131 by the Achtman multilocus sequence typing (MLST) system and a screening PCR assay that targets ST131-specific sequence polymorphisms in the mdh and gyrB genes. However, they are classified as separate STs by the Pasteur Institute MLST system, and an ST131 PCR method that targets the O25b rfb region and an ST131-specific polymorphism in pabB detects only the O25b-associated clade. Here, we describe a novel PCR-based method that allows for rapid and specific detection of the O16-associated ST131 clade. The clade members uniformly contained allele 41 of fimH (type 1 fimbrial adhesin) and a narrow range of alleles of gyrA and parC (fluoroquinolone target genes). The virulence genotypes of the clade members resembled those of classic O25b:H4 ST131 isolates; representative isolates were variably lethal in a mouse subcutaneous sepsis model. Several pulsotypes spanned multiple sources (adults, children, pets, and human fecal samples) and locales. An analysis of recent clinical E. coli collections showed that the O16 ST131 clade is globally distributed, accounts for 1 to 5% of E. coli isolates overall, and, when compared with other ST131 isolates, it is associated with resistance to ampicillin, gentamicin, and trimethoprim-sulfamethoxazole and with susceptibility to fluoroquinolones and extended-spectrum cephalosporins. Attention to this O16-associated ST131 clade, which is facilitated by our novel PCR-based assay, is warranted in future epidemiological studies of ST131 and, conceivably, in clinical applications.

Colonization of the lower urogenital tract with Ureaplasma parvum can cause asymptomatic infection of the upper reproductive system in women: a preliminary study.

PURPOSE: Genital ureaplasmas are considered opportunistic pathogens of human genitourinary tract involved in adverse pregnancy sequelae and infertility. While association of Ureaplasma urealyticum with urogenital tract infections is well established, the role of Ureaplasma parvum in these infections is still insufficient. In the study, we compared how often cervicovaginal colonization with U. parvum is associated with the presence of these microorganisms in the upper genitourinary tract of fertile and infertile women. METHODS: We used PCR assay to determine the prevalence of U. parvum and U. urealyticum in pairs of specimens, i.e., vaginal swabs and Douglas' pouch fluid samples from consecutive 40 women with no symptoms of genital tract infection. RESULTS: In total, 19 (47.5 %) of the 40 samples were positive for ureaplasmas. U. parvum was simultaneously detected in pairs of samples in five (55.5 %) of the nine (47.4 %) women positive in PCR assay. As many as 5 (18.5 %) of the 27 infertile women and 1 (7.7 %) of the 13 fertile women showed infection of the upper genital tract with U. parvum. CONCLUSION: The results of the study demonstrated that colonization of the lower genital tract with U. parvum can produce asymptomatic infection of the upper reproductive system in women. These findings also imply that U. parvum may be present in the upper genital tract at the time of conception and might be involved in adverse pregnancy outcomes.

The capsular polysaccharide and lipopolysaccharide structures of two carbapenem resistant Klebsiella pneumoniae outbreak isolates.

Carbapenem resistant Klebsiella pneumoniae (CRKP) are isolated with increasing frequency, especially from immunocompromized patients. The capsular polysaccharide (CPS) types of CPKP were not determined. Investigation of two CRKP isolates from a 2011 outbreak at the Clinical Center, the National Institutes of Health, identified a new capsular type shared by the two isolates, similar to K. pneumonia K19 and K34 but structurally different than any published K. pneumoniae CPS repeating unit: The LPS of the two isolates was found to have no O-specific polysaccharide and the chemical structure of the core oligosaccharides agreed with the published data. If this structure type will be prevalent among CPKP isolates, our findings could facilitate rapid diagnosis and help to develop new therapeutic solutions to this antibiotic resistant pathogen.

Use of the Real Time xCelligence System for Purposes of Medical Microbiology.

Roche's xCelligence impedance-measuring instrument is one of a few commercially available systems of such type. According to the best knowledge of authors, instrument was tested so far only for eukaryotic cell research. The aim of this work was to estimate xCELLigence suitability for the microbiological tests, including (i) measurement of morphological changes in eukaryotic cells as a result of bacterial toxin activity, (ii) measurement of bacterial biofilm formation and (iii) impact of antiseptics on the biofilm structure. To test the infuence of bacterial LT enterotoxin on eukaryotic cell lines, Chinese Hamster Ovary (CHO) cell line and reference strain Escherichia coli ATTC 35401 were used. To investigate Roche's instrument ability to measure biofilm formation and impact of antiseptics on its development, Staphylococcus aureus ATTC6538 reference strain was used. The data generated during the experiments indicate excellent ability of xCelligence instrument to detect cytopathic effect caused by bacterial LT endotoxin and to detect staphylococcal biofilm formation. However, interpretation of the results obtained during real-time measurement of antiseptic's bactericidal activity against staphylococcal biofilm, caused many difficulties. xCelligence instrument can be used for real-time monitoring of morphological changes in CHO cells treated with bacterial LT enterotoxin and for real-time measurement of staphylococcal biofilm formation in vitro. Further investigation is necessary to confirm suitability of system to analyze antiseptic's antimicrobial activity against biofilm in vitro.

Occurrence of Mycoplasma genitalium in fertile and infertile women.

OBJECTIVE: To determine the frequency of occurrence of Mycoplasma genitalium in the reproductive organs of infertile women in comparison with a control group of healthy, fertile women. DESIGN: Prospective study. SETTING: Gynecology Clinic at the 2nd Department of Gynecology and Obstetrics of the Wroclaw Medical University, Poland. PATIENT(S): The study included 51 patients with primary infertility (24 women with idiopathic infertility) and 23 women with proven fertility. INTERVENTION(S): Cervical smear and smear from the peritoneal cavity, performed during laparoscopy. MAIN OUTCOME MEASURE(S): Presence of the genetic material of M. genitalium in the collected material analyzed using polymerase chain reaction (PCR). RESULT(S): M. genitalium was found in the cervical canal of 19.6% of all infertile patients and in 4.4% of fertile patients. In addition, the pathogen was discovered in the cervical canal of 29% patients with unexplained (idiopathic) infertility, which in comparison with the fertile group was a statistically significant difference. In the abdominal cavity, M. genitalium was found in 5.8% of patients from the infertile group (in 8.4% patients with idiopathic infertility), whereas it was not detected in the material obtained from the studied fertile patients. CONCLUSION(S): The results obtained may suggest that M. genitalium is a species having an impact on impaired fertility in women.

[Frequency of detection of Ureaplasma urealyticum and Mycoplasma hominis in cervical canal and the Douglas pouch of infertile and fertile women]. / Czestosc wykrywania Ureaplasma urealyticum i Mycoplasma hominis w kanale szyjki macicy i jamie otrzewnej u plodnych i nieplodnych kobiet.

The group of organisms commonly referred to as genital mycoplasmas comprise species most often found in genitourinary tract of sexually active adults as common commensal inhabitants, or pathogens which can possibly cause many different pathologies like: non-gonococcal urethritis, bacterial vaginosis, cervicitis, endometritis or pelvic inflammatory disease. The problem of their morbidity and the possible influence they have on human fertility is still not clear. The aim of this study was to find out whether two investigated species- Ureaplasma urealyticum and Mycoplasma hominis can be detect more often in a group of infertile women. 74 women participated in the study and were assigned to one of 2 groups of patients: infertile women and fertile women without any sign of genital tract infection. Swabs from the cervical canal of the uterus and the fluid from the Douglas pouch were taken during the gynecological examination and laparoscopic procedure. Two diagnostic methods were used: biochemical method- commercial diagnostic kit- Mycoplasma IST 2 and PCR method. The results showed that Ureaplasma urealyticum and Mycoplasma hominis were detected among both fertile and infertile women with nearly the same frequency, much more often in cervical canal than in the Douglas pouch. Ureaplasma urealyticum was more common pathogen than Mycoplasma hominis in both groups and locations. The achieved results point out that the role of genital mycoplasmas in human infertility is still unclear and require further investigations.

[The presence of Mycoplasma hominis and Ureaplasma urealyticum in the cervical canal of uterus]. / Obecnosc Mycoplasma hominis i Ureaplasma urealyticum w kanale szyjki macicy kobiet.

OBJECTIVES: Mycoplasma hominis and Ureaplasma species are common commensal inhabitants of the lower genitourinary tract in adolescents and adults who are sexually active. A lot of authors points out that these microorganisms can play an important role in pathology of genital tract like pelvic inflammatory disease, sterility or non-gonococcal urethritis. MATERIALS AND METHODS: In the study samples from cervical canal of the uterus were obtained from 222 women. The first group consist of 132 women who were examined in II Gynecological Clinic in Wroclaw for different, probably infectious, gynecological pathologies (adnexitis, sterility, bacterial vaginosis). 90 women without infectious diseases were in a control group. All swabs taken from cervix were tested for Mycoplasma hominis and Ureaplasma urealyticum. RESULTS: The prevalence of Ureaplasma urealyticum was 31.8% in the first tested group (42 of 132 women were positive) and 8.8% in control group (8 of 90 were positive). 3% (4 of 132) of patients were positive to Mycoplasma hominis in the first group and only 1.1% (1 of 90) in a control group. CONCLUSIONS: Ureaplasma urealyticum was found most often in such genital tract pathologies like acute or recurrent adnexitis, sterility or bacterial vaginosis. No statistically significant correlation was found between the age of the patients and the incidence of mycoplasmas.

[Adhesive properties and antibiotic resistance of Klebsiella strains isolated from gastrointestinal tracts of children hospitalised in Wroclaw nad Opole]. / Wlasciwosci adhezyjne i lekoopornosc szczepów Klebsiella izolowanych z przewodu pokarmowego dzieci hospitalizowanych we Wroclawiu i w Opolu.

Gram negative Klebsiella bacilli present many pathogenic properties, which determine their ability to survive and rapid spreading in hospital environment. There are many factors responsible for the pathogenicity of Klebsiella strains: capsule, fimbriae, nonfimbrial adhesins, lipopolysaccharide of the cell wall and extracellular secreted exotoxins. Klebsiella strains are etiological agents of different nosocomial infections but also colonized gastrointestinal and respiratory tracts. The aim of our work were adhesive properties and antibiotic resistance of Klebsiella strains isolated from stool of hospitalized children, according to source of potential nosocomial infections--100 Klebsiella strains from Wroclaw and 76 strains from Opole, isolated in cases of diarrhea. The resistance of this strains to different group of antibiotics, the expression of ESBL enzymes, the activity in hemagglutination and their ability to adherence to different cell lines were tested. The highest resistance of all strains to aminopenicillins was observed. The production of ESBL was highest in strains from Opole (51% strains) then in Wroclaw (9%). In both hospital units, ESBL+ strains were resistant to aminoglicosides and cotrimoxazol but sensitive to ciprofloxacine. Using hemagglutination method the types of fimbriae were defined. Above 90% investigated Klebsiella strains showed the presence of fimbriae (in Wroclaw more strains simultaneously expressed fimbriae type 1 and 3, in Opole mainly fimbriae type 3). Over 70% strains demonstrated the high level of adherence to cell lines. Only several strains showed the low level or the lack of adhesion. These results suggested that among Klebsiella strains in gastrointestinal tract were presented multiresistant strains with high ability to adherence, which may be potential source of nosocomial infections.