Antibacterial Potential of Non-Tailed Icosahedral Phages Alone and in Combination with Antibiotics.

Non-tailed icosahedral phages belonging to families Fiersviridae (phages MS2 and Qbeta), Tectiviridae (PRD1) and Microviridae (phiX174) have not been considered in detail so far as potential antibacterial agents. The aim of the study was to examine various aspects of the applicability of these phages as antibacterial agents. Antibacterial potential of four phages was investigated via bacterial growth and biofilm formation inhibition, lytic spectra determination, and phage safety examination. The phage phiX174 was combined with different classes of antibiotics to evaluate potential synergistic interactions. In addition, the incidence of phiX174-insensitive mutants was analyzed. The results showed that only phiX174 out of four phages tested against their corresponding hosts inhibited bacterial growth for > 90% at different multiplicity of infection and that only this phage considerably prevented biofilm formation. Although all phages show the absence of potentially undesirable genes, they also have extremely narrow lytic spectra. The synergism was determined between phage phiX174 and ceftazidime, ceftriaxone, ciprofloxacin, macrolides, and chloramphenicol. It was shown that the simultaneous application of agents is more effective than successive treatment, where one agent is applied first. The analysis of the appearance of phiX174 bacteriophage-insensitive mutants showed that mutations occur with a frequency of 10-3. The examined non-tailed phages have a limited potential for use as antibacterial agents, primarily due to a very narrow lytic spectrum and the high frequency of resistant mutants appearance, but Microviridae can be considered in the future as biocontrol agents against susceptible strains of E. coli in combinations with conventional antimicrobial agents.

Serotype distribution, antimicrobial susceptibility and molecular epidemiology of invasive Streptococcus pneumoniae in the nine-year period in Serbia.

Streptococcus pneumoniae is one of the leading bacterial pathogens that can cause severe invasive diseases. The aim of the study was to characterize invasive isolates of S. pneumoniae obtained during the nine-year period in Serbia before the introduction of the pneumococcal conjugate vaccines (PCVs) into routine vaccination programs by determining: serotype distribution, the prevalence and genetic basis of antimicrobial resistance, and genetic relatedness of the circulating pneumococcal clones. A total of 490 invasive S. pneumoniae isolates were included in this study. The serotype, antimicrobial susceptibility, and ST of the strains were determined by the Quellung reaction, disk- and gradient-diffusion methods, and multilocus sequence typing (MLST), respectively. The most common serotypes in this study were 3, 19F, 14, 6B, 6A, 19A, and 23F. The serotype coverages of PCV10 and PCV13 in children less than 2 years were 71.3 and 86.1%, respectively, while PPV23 coverage in adults was in the range of 85-96%, depending on the age group. Penicillin and ceftriaxone-non-susceptible isolates account for 47.6 and 16.5% of all isolates, respectively. Macrolide non-susceptibility was detected in 40.4% of isolates, while the rate of multidrug- and extensive-drug resistance was 20.0 and 16.9%, respectively. The MLST analysis of 158 pneumococci identified 60 different STs belonging to the 16 Clonal Complexes (CCs) (consisting of 42 STs) and 18 singletons. The most common CC/ST were ST1377, CC320, CC15, CC273, CC156, CC473, CC81, and CC180. Results obtained in this study indicate that the pre-vaccine pneumococcal population in Serbia is characterized by high penicillin and macrolides non-susceptibility, worrisome rates of MDR and XDR, as well as a high degree of genetic diversity. These findings provide a basis for further investigation of the changes in serotypes and genotypes that can be expected after the routine introduction of PCVs.

Antibiotic Resistance and Probiotics: Knowledge Gaps, Market Overview and Preliminary Screening.

Probiotics are among those products, the use of which is increasing, and they are available primarily as food/dietary supplements, as well as in the form of medicines. This study aims to assess the attitudes and practices of health professionals and students of health sciences, give a short overview of the probiotics currently on the market, and conduct a screening of five food supplements and one drug with respect to antibiotic resistance. Nearly half of the respondents in our survey state that probiotics have no side effects, while only 6.3% believe that the use of probiotics can lead to antibiotic resistance. In addition, more than 40% of the participants throw unused probiotics into municipal waste. The market analysis results indicate that probiotic products on the Serbian market have highly variable CFU counts, while the declared health claims cover numerous beneficial health effects, and they are sometimes even registered as medicines. Lactobacilli are frequently present in probiotic supplements, and are sold in pharmacies and online. The experimental results showed that antibiotic resistance is present in different types of lactobacilli in probiotic products. The risk of using probiotics, regardless of their beneficial health effects, should be taken into account in the future. An update to the regulations governing probiotics, including a stipulation for antimicrobial resistance (AMR) testing, should be established, and guidelines for their proper use and disposal put into place.

Purple Urine Bag Syndrome in a Home-Dwelling Elderly Female with Lumbar Compression Fracture: A Case Report.

Purple urine bag syndrome (PUBS) is an uncommon, but usually benign, underrecognized clinical condition with the distressing presentation of purple, blue or reddish discoloration of a patient's catheter bag and tubing in the setting of catheter-associated urinary tract infections (UTIs). PUBS is the result of the complex metabolic pathway of the dietary essential amino acid tryptophan. Its urinary metabolite, indoxyl sulfate, is converted into red and blue byproducts (indirubin and indigo) in the presence of the bacterial enzymes indoxyl sulfatase and phosphatase. The typical predisposing factors are numerous and include the following: female gender, advanced age, long-term catheterization and immobilization, constipation, institutionalization, dementia, increased dietary intake of tryptophan, chronic kidney disease, alkaline urine, and spinal cord injury (SCI). Here, we present a case of PUBS in a home-dwelling elderly female patient with a history of long-term immobility after a pathological spinal fracture, long-term catheterization, constipation, and malignant disease in remission. Urine culture was positive for Proteus mirabilis. This state can be alarming to both patients and physicians, even if the patient is asymptomatic. Healthcare professionals and caregivers need to be aware of this unusual syndrome as an indicator of bacteriuria in order to initiate proper diagnostics and treatment.

E6/E7 mRNA Expression of the Most Prevalent High-Risk HPV Genotypes in Cervical Samples from Serbian Women.

Cervical cancer caused by persistent infection with HR HPV genotypes is the second leading cause of death in women aged 15 to 44 in Serbia. The expression of the E6 and E7 HPV oncogenes is considered as a promising biomarker in diagnosing high-grade squamous intraepithelial lesions (HSIL). This study aimed to evaluate HPV mRNA and DNA tests, compare the results according to the severity of the lesions, and assess the predictive potential for the diagnosis of HSIL. Cervical specimens were obtained at the Department of Gynecology, Community Health Centre Novi Sad, Serbia, and the Oncology Institute of Vojvodina, Serbia, during 2017-2021. The 365 samples were collected using the ThinPrep Pap test. The cytology slides were evaluated according to the Bethesda 2014 System. Using a real-time PCR test, HPV DNA was detected and genotyped, while the RT-PCR proved the presence of E6 and E7 mRNA. The most common genotypes in Serbian women are HPV 16, 31, 33, and 51. Oncogenic activity was demonstrated in 67% of HPV-positive women. A comparison of the HPV DNA and mRNA tests to assess the progression of cervical intraepithelial lesions indicated that higher specificity (89.1%) and positive predictive value (69.8-78.7%) were expressed by the E6/E7 mRNA test, while higher sensitivity was recorded when using the HPV DNA test (67.6-88%). The results determine the higher probability of detecting HPV infection by 7% provided by the mRNA test. The detected E6/E7 mRNA HR HPVs have a predictive potential in assessing the diagnosis of HSIL. The oncogenic activity of HPV 16 and age were the risk factors with the strongest predictive values for the development of HSIL.

Impact of Antibiotic Consumption on Antimicrobial Resistance to Invasive Hospital Pathogens.

The aim of our investigation is to correlate the wholesale data on antibiotic consumption expressed in daily doses per 1000 inhabitants per day (DID) with the resistance rate of invasive pathogen bacteria from 2017 to 2021. The data on antimicrobial resistance were collected from an analysis of the primary isolates of hospitalized patients. According to the CAESAR manual, the selected pathogens isolated from blood culture and cerebrospinal fluids were tested. The consumption of antibiotics for systematic use showed a statistically significant increasing trend (ß = 0.982, p = 0.003) from 21.3 DID in 2017 to 34.5 DID in 2021. The ratio of the utilization of broad-spectrum to narrow-spectrum antibiotics increased by 16% (ß = 0.530, p = 0.358). The most consumed antibiotic in 2021 was azithromycin (15% of total consumption), followed by levofloxacin (13%) and cefixime (12%). A statistically positive significant correlation was discovered between the percentage of resistant isolates of K. pneumoniae and consumption of meropenem (r = 0.950; p = 0.013), ertapenem (r = 0.929; p = 0.022), ceftriaxone (r = 0.924; p = 0.025) and levofloxacin (r = 0.983; p = 0.003). Additionally, the percentage of resistant isolates of E. coli and consumption of ertapenem showed significant correlation (r = 0.955; p = 0.011). Significant correlation with consumption of the antibiotics widely used at the community level, such as levofloxacin, and resistance isolated in hospitals indicates that hospital stewardship is unlikely to be effective without a reduction in antibiotic misuse at the community level.

Self-reported antibiotic stewardship and infection control measures from 57 intensive care units: An international ID-IRI survey.

We explored the self-reported antibiotic stewardship (AS), and infection prevention and control (IPC) activities in intensive care units (ICUs) of different income settings. A cross-sectional study was conducted using an online questionnaire to collect data about IPC and AS measures in participating ICUs. The study participants were Infectious Diseases-International Research Initiative (IDI-IR) members, committed as per their institutional agreement form. We analyzed responses from 57 ICUs in 24 countries (Lower-middle income (LMI), n = 13; Upper-middle income (UMI), n = 33; High-income (HI), n = 11). This represented (~5%) of centers represented in the ID-IRI. Surveillance programs were implemented in (76.9%-90.9%) of ICUs with fewer contact precaution measures in LMI ones (p = 0.02); (LMI:69.2%, UMI:97%, HI:100%). Participation in regional antimicrobial resistance programs was more significantly applied in HI (p = 0.02) (LMI:38.4%,UMI:81.8%,HI:72.2%). AS programs are implemented in 77.2% of institutions with AS champions in 66.7%. Infectious diseases physicians and microbiologists are members of many AS teams (59%&50%) respectively. Unqualified healthcare professionals(42.1%), and deficient incentives(28.1%) are the main barriers to implementing AS. We underscore the existing differences in IPC and AS programs' implementation, team composition, and faced barriers. Continuous collaboration and sharing best practices on APM is needed. The role of regional and international organizations should be encouraged. Global support for capacity building of healthcare practitioners is warranted.

First Isolation of Exiguobacterium aurantiacum in Serbia.

Exiguobacterium aurantiacum is isolated from a variety of environmental samples but rarely from patients. The aim of the study was to represent isolation of unusual bacterial strains that could cause infection in patients. Final identification was performed using matrix-assisted description/ionization time-of-flight mass spectrometry (MALDI-TOF). Two isolates strains of E. aurantiacum were isolated, one isolate from distilled water used during surgical treatment and the second one from a patient with bacteremia after radical prostatectomy, both sensitive to all tested antimicrobials. Environmental strains could cause infection, especially in immunocompromised patients; therefore, rare bacteria testing is required, in which identification special assistance is provided by an automated system MALDI-TOF.

Profiles of multidrug-resistant organisms among patients with bacteremia in intensive care units: an international ID-IRI survey.

Evaluating trends in antibiotic resistance is a requisite. The study aimed to analyze the profile of multidrug-resistant organisms (MDROs) among hospitalized patients with bacteremia in intensive care units (ICUs) in a large geographical area. This is a 1-month cross-sectional survey for blood-borne pathogens in 57 ICUs from 24 countries with different income levels: lower-middle-income (LMI), upper-middle-income (UMI), and high-income (HI) countries. Multidrug-resistant (MDR), extensively drug-resistant (XDR), or pan-drug-resistant isolates were searched. Logistic regression analysis determined resistance predictors among MDROs. Community-acquired infections were comparable to hospital-acquired infections particularly in LMI (94/202; 46.5% vs 108/202; 53.5%). Although MDR (65.1%; 502/771) and XDR (4.9%; 38/771) were common, no pan-drug-resistant isolate was recovered. In total, 32.1% of MDR were Klebsiella pneumoniae, and 55.3% of XDR were Acinetobacter baumannii. The highest MDR and XDR rates were in UMI and LMI, respectively, with no XDR revealed from HI. Predictors of MDR acquisition were male gender (OR, 12.11; 95% CI, 3.025-15.585) and the hospital-acquired origin of bacteremia (OR, 2.643; 95%CI, 1.462-3.894), and XDR acquisition was due to bacteremia in UMI (OR, 3.344; 95%CI, 1.189-5.626) and admission to medical-surgical ICUs (OR, 1.481; 95% CI, 1.076-2.037). We confirm the urgent need to expand stewardship activities to community settings especially in LMI, with more paid attention to the drugs with a higher potential for resistance. Empowering microbiology laboratories and reports to direct prescribing decisions should be prioritized. Supporting stewardship in ICUs, the mixed medical-surgical ones in particular, is warranted.

Endemicity of OXA-23 and OXA-72 in clinical isolates of Acinetobacter baumannii from three neighbouring countries in Southeast Europe.

According to the World Health Organization, bacterium Acinetobacter baumannii is the first on the critical priority list of pathogens in urgent need for new antibiotics. The increasing resistance of A. baumannii to the last-line treatment options, including carbapenems, is a global problem. We report the molecular epidemiology of 12 carbapenem-resistant clinical isolates of A. baumannii collected from hospitalised patients in three neighbouring countries in Southeast Europe: Croatia, Serbia, and Bosnia and Herzegovina, giving an insight into the molecular characterisation and evolutionary history of the acquisition of resistance genes. Besides the blaOXA-23 gene, the endemic presence of OXA-72 oxacillinase of the same origin for more than a decade as the leading mechanism of carbapenem resistance in Southeast Europe was confirmed. To the best of our knowledge, this is the first paper that investigates and analyses the phylogenetic association of the most common mechanisms of resistance to carbapenems in clinical isolates of A. baumannii originating from three neighbouring countries in Southeast Europe.

Candida bloodstream infections in Serbia: First multicentre report of a national prospective observational survey in intensive care units.

Candida bloodstream infections (BSI) are a significant cause of mortality in intensive care units (ICU), hereof the prospective 12-months (2014-2015) hospital- and laboratory-based survey was performed at the Serbian National Reference Medical Mycology Laboratory (NRMML). Candida identification was done by a matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry and a susceptibility test, according to the Clinical and Laboratory Standards Institute methodology. Among nine centres (265 beds; 10 820 patient admissions), four neonatal/paediatric (NICU/PICUs) and five adult centres (ICUs) participated, representing 89 beds and 3446 patient admissions, 166 beds and 7347 patient admissions respectively. The NRMML received 43 isolates, 17 from NICU/PICUs and 26 from adult ICUs. C. albicans dominated highly in NICU/PICUs (~71%), whereas C. albicans and C. parapsilosis were equally distributed within adults (46%, each), both accounting for ~90% of received isolates. The resistance to itraconazole and flucytosine were 25% and 2.4% respectively. In addition, the 2 C. albicans were azole cross-resistant (4.6%). The overall incidence of CandidaBSI was ~3.97 cases/1000 patient admissions (4.93 in NICU/PICU and 3.53 in adult ICU). The 30-day mortality was ~37%, most associated with C. tropicalis and C. glabrataBSI. Data from this national survey may contribute to improving the Balkan and Mediterranean region epidemiology of CandidaBSI within ICUs.

Molecular Epidemiology of Colistin-Resistant, Carbapenemase-Producing Klebsiella pneumoniae in Serbia from 2013 to 2016.

Twenty-seven colistin-resistant, carbapenemase-producing Klebsiella pneumoniae isolates were identified from hospitals in Serbia. All isolates were blaCTX-M-15 positive; ST101, ST888, ST437, ST336, and ST307 were blaOXA-48 positive; and ST340 was blaNDM-1 positive. ST307 had an insertion, and ST336 had a premature stop codon in the mgrB gene. Amino acid substitutions were detected in PmrAB of isolates ST101, ST888, ST336, and ST307. The mcr-1 and mcr-2 were not detected. An increase in phoP, phoQ, and pmrK gene transcription was detected for all sequence types.

Detection of carbapenemase genes in Klebsiella pneumoniae isolates.

Introduction: Klebsiella pneumoniae is one of the leading causes of serious hospital-acquired infections worldwide among Enterobacteriaceae species. It is the most common producer of carbapenemases in many parts of the world. Objective: The aim of the study was to determine which enzymes were responsible for resistance to carbapenems in Klebsiella pneumoniae strains isolated at the Centre of Microbiology of Public Health Institute of Vojvodina. Methods: A total of 29 Klebsiella pneumoniae non-duplicated strains resistant to at least one carbapenem isolated from clinical samples of hospitalized patients between November 1st 2013 and April 30th 2014 were studied. The species identification and susceptibility were done using VITEK 2 (bioMérieux, Marcy-l'Étoile, France) system. Phenotypic conformation of carbapenemase production was done by double-disc synergy test. PCR technique was performed for detection of genes encoding production of carbapenemases (bls(KPC), bla(VIM), bla (NDM), bla(OXA-48)). Results: Isolates of Klebsiella pneumoniae resistant to at least one carbapenem showed positive on double- disc synergy test between meropenem and dipicolinic acid. All strains positive in phenotypic test contained bla(NDM) gene. In isolates resistant only to ertapenem, neither production of carbapenemases nor presence of genes encoding these enzymes were detected. Among these isolates, nine produced extended-spectrum ß-lactamase. Conclusion: The presence of NDM metallo-ß-lactamase was determined in all Klebsiella pneumoniae isolates resistant to at least one carbapenem.

Streptococcus pneumoniae serotype distribution in Vojvodina before the introduction of pneumococcal conjugate vaccines into the National Immunization Program.

Introduction: Streptococcus pneumoniae is the most common causative agent of bacterial pneumonia and meningitis. Mandatory childhood immunization against pneumococcal diseases is introduced in the new Law on Protection of Population against Communicable Diseases in Serbia. Objective: The objective of this study was to determine the prevalence of pneumococcal serotype distribution in Vojvodina region before routine use of pneumococcal conjugate vaccine in Serbia. Methods: A total of 105 isolates of Streptococcus pneumoniae were collected in the period from January 2009 to April 2016. Based on the results of serotyping in the National Reference Laboratory, we analyzed distribution of circulating serotypes and coverage of conjugate and 23-valent polysaccharide pneumococcal vaccines in different age groups. Results: Among 105 isolates, a total of 21 different serotypes of Streptococcus pneumoniae were determined. The most frequent serotypes were 3 (21.9%), 19F (20.0%), and 14 (10.5%). The serotype coverage of pneumococcal conjugate vaccines (PCV7, PCV10, and PCV13) was 48.6%, 54.3%, and 84.8%, respectively, while pneumococcal polysaccharide vaccine (PPV23) covered 89.5% of the total number of isolates in all age groups. Serotypes included in PCV7, PCV10, and PCV13 represented 72.0%, 76.0%, and 88.0% of the total number of isolates in children ≤5 years, respectively. Vaccine serotype coverage of PCV13 and PPV23 ranged from 87.1% to 90.3% in adults 50­64 years of age, and 77.8% to 85.2% in adults ≥65 years old. Conclusion: Serotype distribution of Streptococcus pneumoniae in the population fairly overlaps with the serotypes contained in pneumococcal vaccines, so that implementation of childhood immunization is justified. The study was done in the Province of Vojvodina but the findings may be applied to Serbia as a whole.

Resistance of Escherichia coli from healthy donors and from food--an indicator of antimicrobial resistance level in the population.

Escherichia coli, being an important part of normal intestinal flora, is a frequent carrier of antimicrobial drug resistance markers and food is the most important vector of antimicrobial resistance genes between humans and animals. The aim of this study was to confirm the presence and frequency of resistance markers in Escherichia coli from intestinal flora and from food as an indicator of antimicrobial resistance level in the population. The experiment included 100 fecal Escherichia coli isolates from healthy donors, 50 isolated in 2007 and 50 in 2010, and 50 from food samples. The resistance markers were found in all groups of isolates. The resistance to ampicillin and cotrimoxazole was most commonly found. The finding of multi-drug-resistant strains and resistance to ciprofloxacin is important. The frequency of resistance markers was similar in food and feces. The results of this study show the need to introduce systematic monitoring of antimicrobial resistance of these bacteria.

[Carbapenems resistance of Acinetobacter spp strains isolated from wound swabs during 2009-2010].

INTRODUCTION: Acinetobacter spp has become an important cause of nosocomial infections due to its great ability to survive and spread in a hospital setting and to develop resistance to many antibiotics. The aim of this study was to examine the resistance to carbapenems and other commonly used antibiotics in strains of Acinetobacter isolated from wound swabs. MATERIAL AND METHODS: In the Laboratories of Microbiology Center at the Institute for Public Health in Novi Sad wound swabs were taken from the patients hospitalized at the Institutes and Departments of the Clinical Center of Vojvodina in Novi Sad. A total of 271 Acinetobacter spp strains were tested to susceptibility on carbapenems and other most commonly used antibiotics by disk diffusion method according to the recommendation of the Clinical and Laboratory Standards Institute. RESULTS AND DISCUSSION: Acinetobacter spp (271 isolates) developed resistance to imipenem and meropenem (67.4% and 64.4%). The resistance to both cephalosporins III and IV generation and ciprofloxacin was 100%. The resistance to ampicillin-sulbactam was 71.4%. CONCLUSION: Our results show high resistance to carbapenems in Acinetobacter spp strains isolated from wound swabs. These facts suggest the need for continuous monitoring of susceptibility in order to take adequate measures to prevent and control spreading of resistant strains.

[Sensitivity of bacteria to antimicrobial drugs and interpretation of results].

INTRODUCTION: The discovery of antimicrobial drugs was a turning point in the permanent conflict between the mankind and microorganisms. However, due to the wide use and misuse of antibiotics in therapy and prophylaxis of infections the mankind is threatened by an alarming rise in the resistance of bacteria to drugs. Will this phenomenon turn us back to the pre-antibiotic era? DISCUSSION: The increasing resistance of bacteria has become a global public health problem: bacteria are showing a remarkable capacity to develop different mechanisms and avoid drug effect. Mechanisms of resistance are numerous and various: production of beta-lactamases (Ambler class A): TEM-I, TEM-2 and SHV-1 and mutants of classical enzymes with extended spectrum (ESBL) (e.g. in Klebsiella spp.) which results in the resistance to the 3rd generation cephalosporines and new metallo-beta-lactamases among Pseudomonas and Acinetobacter (resistance to carbapenems). The alteration of the target enzymes (PBP) leads to the Staphylococci resistance to methicillin and the responsible gene is mecA gene). The alteration of DNA gyrase due to the mutations of gyrA, gyrB, parC genes (accumulation of multiple mutations) results in the development of resistance to fluoroquinolones); and the active efflux system - "pumping out" of the drug from the bacterial cell leads to the resistance of a wide spectrum of different antibiotics. In order to choose the most efficient drug for therapy, it is necessary to investigate susceptibility of bacteria to antimicrobial agents. For that purpose, a disc-diffusion method according to CLSl standard procedure is performed. For invasive strains it is often necessary to determine minimal inhibitory concentrations (MIC) of antimicrobials. The methods that are in use are agar-dilution methods, E-test and automated MIC determination by VITEK 2 system. CONCLUSION: By molecular-biological methods it is possible to identify the mechanisms of resistance and detect the specific genes behind it (mecA gene). The targeted therapy prevents compromising of antibiotics valuable in treatment of severe infections (carbapenems).

[Antimicrobial resistance of the bacteria isolated from blood cultures in 2007].

INTRODUCTION: Antimicrobial resistance become emerging global problem. Particularly dramatic increase in the number and type of bacteria resistant to numerous and structurally different antibiotics has taken place in the last two decades. MATERIALS AND METHODS: A total of 558 strains of different bacteria isolated from blood cultures during 2007 were tested to susceptibility to different antibiotics by disc diffusion method according to CLSI. All strains were isolated and identified in the laboratories of Microbiology Center at the Institute for Public Health in Novi Sad. A total of 7748 blood cultures were processed and microorganisms were isolated from 558 of them. Blood samples were taken from the patients hospitalized in the Institutes and Clinics of Novi Sad Clinical Center and Institute for Health Care of Children and Adolescents in Novi Sad RESULTS: The structure ofpathogens shows that the most frequent isolates are Gram-positive bacteria, above all coagulase- negative staphylococci with 285 isolates (51,1%) followed with Enterococcus spp (41 isolates - 6,8%). Percentage of resistance to Methicillin in staphylococci strains was 66,7%; all isolates was susceptible to Vancomycine. Enterococcus spp showed 13,2% resistance to Vancomycine. Among Gram-negative pathogens, we find that the most frequent is Klebsiella spp with 40 isolates (7,2%) and have high resistance to wide spectrum Cephalosporins - 82,5%. Acinetobacter spp participate with 41 isolates (7,3%) and 43,9% isolates are resistant to Imipenem Also, Pseudomonas aeruginosa (20 isolates) shows high resistance to Imipenem (40%) but lower resistance to wide spectrum Cephalosporines (27,8%). CONCLUSION: Having compared the resistance to antibiotics in 2002 and 2007 speak for the trend of growing antimicrobial resistance to the very antibiotics which are recommended as the empiric or initial therapy-wide spectrum Cephalosporins, Fluoroquinolons and Imipenem.

[Frequency of methicilin-resistant Staphylococcus aureus strains in clinical spacimens obtained from hospitalized patients in 2007].

INTRODUCTION: Staphylococcus aureus is a major cause of both hospital- and community-acquired infections worldwide. Since the introduction of methicillin into clinical use, methicillin-resistant S. aureus strains have emerged with increasing frequency throughout the world. The aim of the study was to determine frequency of resistance to methicillin and other most commonly used antibiotics of S aureus strains isolated from hospitalized patients. MATERIAL AND METHODS: During the period 1.1.-31. 12. 2007, 226 strains of S. aureus isolated from hospitalized patients were tested for their susceptibility to penicillin, methicillin, erythromycin, clindamycin, gentamycin, sulfamethoxazolle-trimethoprim, fusidic acid and vancomycin using disc diffusion technique. RESULTS: Resistance to methicillin was detected in 20 (7.5%) S. aureus strains. All of them were susceptible to vancomycin. The resistance to other antimicrobial agents varied from 5% for sulfamethoxazolle-trimethoprim to 75% to gentamycin. Among methicillin susceptible strains, high resistance (84.1%) was found to penicillin only The resistance to other antimicrobial agents was low, ranging from 0 for fusidic acid and vancomycin to 12.2% for gentamycin. CONCLUSION: Our results show low rate of methicillin-resistant S. aureus strains compared to other authors "findings, but also the presence of multidrug-resistant isolates and isolates susceptible to vancomycin only These facts suggest the need for further monitoring of susceptibility in order to take adequate measures to prevent and control spreading of resistant strains.